School of Electronic, Communication and Electrical Engineering
MSc Radio and Mobile Communications Systems
Final Year Project Report
School
of
Electronic,
Communication
University of Hertfordshire
Speed Control of Induction Motor
Report by
Muhammad Nasir
Supervisor
Georgois Pissandis
Date
01 September 2008
i
and
M.S.c. Final Year Project Report
Electrical
Engineering
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
DECLARATION STATEMENT
I certify that the work submitted is my own and that any material derived or quoted from the
published or unpublished work of other persons has been duly acknowledged (ref. UPR
AS/C/6.1, Appendix I, Section 2 – Section on cheating and plagiarism)
Student Full Name: Muhammad Nasir
Student Registration Number: 05132611
Signed: …………………………………………………
Date: 16 March 2016
ii
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
ABSTRACT
This report describes the Speed Control of V/F induction using ADMC-330 and DSP processor
BF-533. A system needs to be build that can control the voltage and frequency when input to the
induction motor. The project has two parts. Hardware part included building the Voltage Source
Inverter use to drive the induction motor. The software part includes development of software for
DSP so that speed of induction motor can control. The hardware part was completed but software
part was not completed.
iii
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
ACKNOWLEDGEMENTS
I am thankful to my supervisor Georgois Pissandis, my family and friends that help me and
encourage me every time throughout the project.
iv
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Contents
DECLARATION STATEMENT ................................................................................................... ii
ABSTRACT ................................................................................................................................... iii
ACKNOWLEDGEMENTS ........................................................................................................... iv
List of Figures ............................................................................................................................... vii
1: Introduction ................................................................................................................................. 1
1.1 Overview ............................................................................................................................... 1
1.2 Aims and Objectives ............................................................................................................. 1
1.2.1 Aim ................................................................................................................................ 1
1.2.2 Objectives ...................................................................................................................... 2
1.3 Purposed Architecture ........................................................................................................... 2
1.4 Report Chapter Overview ......................................................................................................... 2
1.4.1 Chapter 1: Introduction ...................................................................................................... 2
1.4.2 Chapter 2: Theoretical Background .................................................................................. 3
1.4.3 Chapter 3: Hardware .......................................................................................................... 3
1.4.4 Chapter 4: Software ........................................................................................................... 3
1.4.5 Chapter 5: Results .............................................................................................................. 3
1.4.6 Chapter 6: Discussion on Results ...................................................................................... 3
1.4.7 Chapter 7: Conclusion........................................................................................................ 3
2: Theoretical Background .............................................................................................................. 4
2.1 Induction Motor .................................................................................................................... 4
2.1.1 Stator .............................................................................................................................. 4
2.1.2 Rotor .............................................................................................................................. 5
2.2 Voltage Source Inverter ........................................................................................................ 6
2.3 Digital Signal Processor ........................................................................................................ 7
2.4 Control Theory ...................................................................................................................... 8
2.4.1: Open Loop Control Drivers .......................................................................................... 8
2.4.2: Close Loop Control Device .......................................................................................... 9
3: Hardware ................................................................................................................................... 11
3.1 International Rectifier Actives-and-Passives (IRAM) ........................................................ 11
3.2 6N137 Optocoupler ............................................................................................................. 12
v
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
3.3 Current Transducer LTS 15-NP .......................................................................................... 13
3.4 Boot-Strap Capacitors ......................................................................................................... 14
3.5 DC Bus Capacitors .............................................................................................................. 15
3.6 Maxin Low Power 8 Channel Serial 12 Bit ADC............................................................... 15
3.7 ADMC-330 ......................................................................................................................... 16
3.7.1ADMC-330 Motion Control Processor ......................................................................... 17
3.7.2 ADMC-330 Architecture ............................................................................................. 18
3.7.3: Functionality ............................................................................................................... 19
3.8: ADMC-330 Evaluation Board ........................................................................................... 20
3.8: Voltage Source Inverter ..................................................................................................... 22
4: Software .................................................................................................................................... 24
4.1: Pulse Width Modulation (PWM) Concepts ....................................................................... 24
4.2: Serial Parallel Interface ...................................................................................................... 25
4.3: Flow Charts ........................................................................................................................ 26
4.3.1: BF ADC Initialization................................................................................................ 27
4.3.2: ADMC ADC Initialization.......................................................................................... 28
4.3.3: PWM Initialization ..................................................................................................... 28
4.3.4: PWM Initialization ..................................................................................................... 30
4.3.5: ADC Read ................................................................................................................... 31
4.3.6 ADC Read .................................................................................................................... 31
4.3.7: ADC Write .................................................................................................................. 33
4.3.7: ADC Write .................................................................................................................. 34
4.4: Discussion .......................................................................................................................... 34
5: Conclusion and Future Work .................................................................................................... 35
5.1: Overall Progress ................................................................................................................. 36
5.2: Future Development ...................................................................................................... 36
5.3: Suggestions .................................................................................................................... 36
References ..................................................................................................................................... 36
Appendix 1 .................................................................................................................................... 38
vi
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
List of Figures
Figure1. 1: Purposed Architecture .................................................................................................. 2
Figure2. 1: Three Phase Induction Motor Diagram. [3]. ................................................................ 4
Figure2. 2: A TYPICAL STATOR [1]. .......................................................................................... 5
Figure2. 3: A TYPICAL SQUIRREL CAGE ROTOR [1]............................................................. 6
Figure2. 4: Block Diagram of ADSP-BF533 [9]. ........................................................................... 8
Figure2. 5: An open loop drive without feedback [18]. .................................................................. 9
Figure2. 6: Close Loop Drive Feedback [18]. .............................................................................. 10
Figure3. 1: 6N137 Optocouplor [13]. ........................................................................................... 12
Figure3. 2: Components connected with 6N137........................................................................... 13
Figure3. 3: internal structure of LTS 15-NP. [14]. ....................................................................... 14
Figure3. 4: Graph form output voltage of sensor [14]. ................................................................. 14
Figure3. 5: Recommended minimum Boot-Strap Capacitors Vs Switching Frequency. [10]...... 15
Figure3. 6: ADMC-330 ................................................................................................................. 16
Figure3. 7: ADMC-330 Architecture View. [16]. ........................................................................ 18
Figure3. 8: ADMC-330 Functional Block Diagram. [16]. ........................................................... 19
Figure3. 9: ADMC-300 Evolution Board. [16]. ........................................................................... 21
Figure3. 10: Ideal Voltage Source Inverter. [19]. ......................................................................... 22
Figure3. 11: Output if Voltage Source Inverter (VSI) .................................................................. 23
Figure4. 1: PWM waveform example [24]. .................................................................................. 25
Figure4. 3: Main Flow Chart ........................................................................................................ 26
Figure4.3. 1: ADC Initialization Flow Chart ................................................................................ 27
Figure4.3. 2: ADC initialization Flow Chart ................................................................................ 28
Figure4.3. 3: PWM initialization Flow Chart ............................................................................... 29
Figure4.3. 4: ADC Initialize (ADMC) Flow Chart....................................................................... 30
Figure4.3. 5: ADC Read Flow Chart ............................................................................................ 31
Figure4.3. 6: ADC Read Flow Chart ............................................................................................ 32
Figure4.3. 7: ADC Write Flow Chart ........................................................................................... 33
Figure4.3. 8: ADC Write Flow Chart ........................................................................................... 34
vii
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
1: Introduction
1.1 Overview
The title of the project is Speed control of Induction Motor. The project should be capable V/F
control system. ADMC-330 is to be used that is a Digital Signal Processor. A motor is used that
is induction motor. The project is concerned with the development of both current and speed
close loop control system. The requirement is for the designing of commonly software and
hardware components. It is a closed loop control system based on V/F strategy. Software
components involved with the development of both current and speed controller algorithms.
Hardware components consists of the development 3-leg DC-AC (inverter), Equipment DSP,
Op-amps ICs, Current sensors, software tools and inverter Technical Challenge Statement.
The need for complicated solution for motor control persists to rise in the consumer, appliance,
industrial and automotive markets. A broad selection of motor types are in use, relying on the
application; the most common are the AC induction motor, permanent magnet synchronous
motor, brushless DC motor and newer design as the switched reluctance motor. Surely, the
majority of the applications which were earlier subject by steady speed, mains fed induction
motors, now obligatory the sophistication of variable speed control. In some applications, for
instance compressors, fans and pumps, this require for enlarged superiority is driven by
legislation and users demand for higher working efficiencies. High performance application in
process control, robotics and machine tools require variable speed and improved accuracy,
possible only if the use of classy control algorithms. [17].
The answer to real time achievement of urbane control algorithm for these motion control
systems has been the arrival of powerful digital signal processor (DSP). Even in less challenging
but cost sensitive applications such as domestic refrigerator compressor drivers, the power of the
DSP can be utilized to put into perform sensor-less control algorithms that decreases the system
cost and raise the overall strength of the drive. In high performance serve drivers, the great
calculative ability of the DSP allows additional accurate control throughout vector control, ripple
torque reduction, predictive control structure, and compensation for non ideal system actions.
[17].
In addition the controlling DSP core, all motor control system have need of an important array of
supplementary circuit for right operation, these functions are as fallowing.
Analog to Digital conversion for current of voltage feedback
Pulse Width modulation blocks for generation of the inverter switching commands
Position sensor interfaces for higher performance applications
Serial ports for host communications
General purpose digital input/output (I/O) ports [17].
1.2 Aims and Objectives
The Aim and Objectives of the project are as fallow.
1.2.1 Aim
Build a system that is capable of controlling the speed of V/F induction motor.
Muhammad Nasir
Speed Control of Induction Motor
1
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
1.2.2 Objectives
To familiar with the speed control of V/F induction motor.
To familiar with Digital Signal Processor (DSP) ADMC 330.
To familiar with the Voltage Source Inverter and workout how induction motor can be
used with source inverter.
To familiar with the use of speed sensor and how the speed sensor give feedback to
ADMC 330.
To produce the V/F graph controlled by change in wavelength and amplitude.
Design a software program that could be used for controlling the hardware.
1.3 Purposed Architecture
The purposed architecture is as fallowing.
Figure1. 1: Purposed Architecture
The User speed set is the point from where the input to the system should be controlled by user
and it should be input to user. This input should go to DSP i.e. ADMC 330 and it is controlled by
the program / software. Next component should be Voltage Source Inverter. It will take input
from DSP and it will perform as the power stage. The output of the Voltage Source Inverter
should produce the 3-phase out and that 3-phase output should drive the induction motor. The
feedback shown in figure is current sensor that is used as the feedback. It should give feedback to
DSP.
1.4 Report Chapter Overview
1.4.1 Chapter 1: Introduction
This chapter gives reader an overview about the project.
Muhammad Nasir
Speed Control of Induction Motor
2
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
1.4.2 Chapter 2: Theoretical Background
This chapter will give reader the knowledge of background theory of the project. It also contain
the useful information about the project that a reader may need while studying.
1.4.3 Chapter 3: Hardware
This chapter includes the knowledge about the hardware of the project and the knowledge about
the methodology that is necessary to complete the project.
1.4.4 Chapter 4: Software
This chapter includes the software part of the project.
1.4.5 Chapter 5: Results
This chapter displays any results that obtained during the project time.
1.4.6 Chapter 6: Discussion on Results
This chapter discusses the results in detail that obtain during the project and discussed in last
chapter.
1.4.7 Chapter 7: Conclusion
This chapter will conclude the project report and conclude how far project goes.
Muhammad Nasir
Speed Control of Induction Motor
3
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
2: Theoretical Background
In this chapter background theory is discussed.
2.1 Induction Motor
AC induction motors are the most frequent motors used in main powered home appliances and
industrial motion control systems. Low cast, low maintenance, easy to design direct connection
to an AC power source are the main benefits of using an AC induction motors. Different types of
AC induction motors are used and available in the market. Different motors are appropriate for
different applications. Although AC induction motors are easier to design than DC motors, the
speed and the torque control in different types of AC induction motors need a better
understanding of the characteristic and design of these motors. [1].
The three phase method is usually take upper hand over the single phase. These kinds of
machines are at benefit because the speed of the motor can be easily controlled and they also
have a good torque.
Figure2. 1: Three Phase Induction Motor Diagram. [3].
From figure is can be seen that induction motor has two main parts, one is stator and other is
rotor. The stator is part of remains still and rotor is the revolving part. They are separated by an
air gap between them. These parts are described as fallow
2.1.1 Stator
The stator is made up of different thin laminations of aluminum or cast iron. They are thumped
and pressed together to form a hollow cylinder (stator core) with slots as shown in Figure 2.2.
Muhammad Nasir
Speed Control of Induction Motor
4
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Coils of insulated wires are placed in into these slots. Each grouping of coils, along with the core
of its surrounds, shapes an electromagnet (pair of poles) on the application of AC supply. The
amount of poles of an AC induction motor depends on the internal connection of the stator
windings. The stator windings are connected straight to the power source. On the inside they are
connected so that on applying AC supply, a rotating magnetic field is created. [1].
Figure2. 2: A TYPICAL STATOR [1].
2.1.2 Rotor
The rotor is made from different thin steel laminations with evenly spaced bars, which are made
of aluminum or copper. In the most liked type of rotor (squirrel cage rotor), these bars are linked
at ends mechanically and electrically by the use of rings. Approximately 90% of induction
motors have squirrel cage rotors. This is since the squirrel cage rotor has a simple and rugged
construction. The rotor consists of a cylindrical coated core with axially positioned parallel slots
for carrying the conductors. Each slot carries a copper, aluminum, or alloy bar. These rotor bars
are permanently short-circuited at both ends by means of the end rings, as shown in Figure 2.3.
These assembly look likes a squirrel cage, this is because rotor has its name. The rotor slots are
not precisely parallel to the shaft. As an alternative, they are specified a tilt for two main causes.
The first motive is to run the motor run quietly by dropping magnetic vibrate and to reduce slot
harmonics.
The second cause is to help decrease the locking tendency of the rotor. The rotor teeth tend to
stay locked underneath the stator teeth because of direct magnetic pull between the two. This
occurs when the number of rotor teeth is equal to the number of stator teeth. The rotor is placed
on the shaft using bearing on each end; one end of the shaft is normally set aside longer than the
other for driving the load. Some motors can have an accessory shaft on the non-driving end for
mounting speed or position sensing devices. Among the stator and the rotor, there present an air
gap, through which because of induction, the energy is moved from the stator to the rotor. The
Muhammad Nasir
Speed Control of Induction Motor
5
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
produced torque forces the rotor and then the load to rotate. In spite of the type of rotor used, the
principle engaged for rotation leftovers the same.
Figure2. 3: A TYPICAL SQUIRREL CAGE ROTOR [1].
An induction motor (IM) is an AC motor where power is supplied to the rotating device by
induction. An electric motor converts electrical power to mechanical power in its rotor (rotating
part). There are different methods to provide power to the rotor. In a DC motor this power is
supplied to the armature directly from a DC source. But in an AC motor this power is induced in
the rotating device. An induction motor can be called a rotating transformer because the stator
(stationary part) is basically the main side of the transformer and the rotor (rotating part) is the
minor side. Induction motors are commonly used, especially polyphase induction motors, which
are often used in industrial drives.
Induction motors are now the favored picking for industrial motors because of their rugged
structure, lack of brushes and the capacity to control the speed of the motor. [4].
An option to using an induction motor is using a DC motor. The benefits of using an induction
motor rather than a DC motor are as shown below. [5].
1. No communication problems.
2. Longer lifespan.
3. Simple and reliable.
4. Less maintenance required.
2.2 Voltage Source Inverter
An inverter is an electrical device that transfers direct current DC to alternating current AC. As a
result, AC can be at any necessary voltage with the use of a transformer. Inverters are used in
extensive range of applications, from small switching power supplies in computers to large
electric utility applications that move build power. The electrical inverter is in result a high
power electric oscillator. It is called inverter because early on mechanical Ac to DC converters
Muhammad Nasir
Speed Control of Induction Motor
6
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
was prepared to work in reverse, and therefore was inverted to change Dc to AC. The inverter
makes the opposed function of rectifier. [20].
Three phase inverter are utilized for changeable frequency drive applications and for high power
applications such as HVDC power transmission. A typical three phase inverter made of three
single phase inverter switched all connected to one of the three load terminals. For the majority
base control technique, the process of the three switches is synchronized so that one switch
functions at each 60 degree point of the basic output waveform. This shaped a line to line output
waveform that has six ladder steps. The six ladder step waveform has a zero voltage step
connecting the positive and negative section of the square wave such that the harmonic that are
multiples of three are removed as explained above. When carried based PWM methods are
functional to six step waveform, the basic in general shape, or enclose, the waveform is keeped
so that the 3rd harmonic and its multiples are stopped. [20].
To build inverters with high power ratio, two six steps three phase inverters can be linked in
parallel for high current evaluation or in series for high voltage rating. In each situation, the
output waveforms are phase shifted to get 12 waveforms. If supplementary inverters are joined,
an 18 step inverter is acquired with three inverters. Even though inverters typically combined for
the reason of achieving enlarged voltage or current rating, the quality for the waveform is
improves as well. [20].
2.3 Digital Signal Processor
There are three main functions of digital signal processor.
1. Converting the received analogue signal into digital from.
2. Process the digital signal.
3. Convert the processed digital signal back into analogue form. [8].
In order for the first step to be accomplished a sample and hold circuit needs to build. This is so
that the analogue input can be sampled at periodic intervals and grasps the sampled value
constant at the input conversion can be precise. [8].
The analog signal is a step waveform once it has been through the sample and hold system. The
ADC then changes this signal into binary form in order for the signal to be processed in the DSP.
Therefore once processed by the DSP the DAC will change the new binary value into a new step
analogue waveform.
After finishing of the third step the analogue signal must flow through a low pass filter. This is
done in order to eliminate any unnecessary high frequency components, so the output will have
the desired processed analogue signal. [8].
Some advantages of using DSP are shown.
1. No need exact values of digital signals, thus tolerances assorted components
cannot change the final outcome.
2. Digital circuits can be imitated again.
3. DSP systems can be containing on to a single chip.
4. Correctness of DSP signals can be enhanced simply by adding more words to the
binary data. [8].
The ADSP-BF533 processor is compatible for digital motor control, joining the DSP’s
calculation capacity on a single chip. This hybrid controller propose several devoted peripherals,
including a Pulse Width Modulation (PWM) unit, an Analog-to-Digital Converter (ADC),
Muhammad Nasir
Speed Control of Induction Motor
7
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
timers, communication peripherals (SCI, SPI, and CAN), on-board Flash and RAM. Generally,
ADSP-BF533 is appropriate for use in AC induction motor control. [9].
Figure2. 4: Block Diagram of ADSP-BF533 [9].
There are different important concepts of BF-533 like dead time and pulse deletion logic that are
useful for this project are discussed in software chapter.
2.4 Control Theory
As the speed of the magnetic field is directly proportional to the frequency, they will be no
control over the speed of the motor. This problem was resolved with the creation of the inverter
drive, which can supply the motor with an AC signal of varying frequency. The drive will be
capable to accept fixed voltage and frequency input from the power supply, and invert it to
provide and AC output. This will then be varied independently. The overall effect is to give the
user the control of the speed and torque of the AC induction motor.
There are two types of inverter drivers for induction motors. [18].
2.4.1: Open Loop Control Drivers
The open loop control inverter drivers are moreover referred to as an open variables frequency
driver and an open loop AC variable speed driver. The main dissimilarity among the open loop
inverter and rest is that it does not have any type of velocity feedback. Lacking feedback,
accurate speed control on an induction motor is hard because of the usual slip of the motor. As
the synchronous motor dose not slips, its speed can be controlled with very exact signal with a
changeable frequency, comparative to the reference speed signal. Consecutively to generate an
AC signal with a changeable frequency, the DC supply is send to inverter. The inverter, beside
by the control circuits, makes a switching voltage output in a way alike to that of the DC chopper
drive. The switching technique utilizes transistors to switch on and off the voltage signal at a
high frequency. By changeable the span of time that the voltage signal is on, the inverter creates
an average voltage that is similar to a sinusoidal curve. The speed reference signal characterizes
Muhammad Nasir
Speed Control of Induction Motor
8
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
the speed of the rotating magnetic field which strongly associates with the no load speed of an
induction motor. [18].
With enlarged load, the slip of the motor will increase, reasoning the speed to reduce. For
application with low loads or states that do not need exact speed control, the open loop inverter
drive will be adopted. By rising application requirements, you may want to look to close loop
inverter drive which incorporates velocity feedback. [18].
Motion controller
Motion Driver
Motion Device
Figure2. 5: An open loop drive without feedback [18].
2.4.2: Close Loop Control Device
The Close Loop Control Inverter Drives also indicated as a closed loop variable frequency drive
or a closed loop variable speed drive. It is very alike to the open loop version with the adding of
the speed reaction. This closed loop inverter drive is mostly used to control the induction motor,
which needed an AC signal to create motion. The speed of the motion is associated to the
frequency of the signal. In order to generate an AC signal with a changeable frequency, the DC
supply is send to an inverter. An inverter beside with the control circuit makes a switching
voltage output in a way alike to that of the DC chopper drive. The switching method uses
transistors to turn on and off the voltage signal to that of the DC chopper drive. The switching
method uses transistors to turn on and off the voltage signal at a high frequency. By the changing
of the span of time that the voltage signals is on, the inverter makes a typical voltage signal that
looks like a sinusoidal curve. The current waveform shaped by this switched voltage, symbolizes
a sinusoidal curve a lot more exactly than the voltage waveform. The dissimilarity among the
open loop and close loop inverters is that the speed orientation signal represents the speed of the
rotor instead of speed of the revolving magnetic field or the no load speed. The speed reference
signal is evaluated to the feedback signal and alterations are made for any error. In loaded
applications, the speed of the revolving magnetic field is amplified beyond the preferred speed in
turn to recompense for induction motor slip. [18].
The closed loop inverter driver is able of accurate speed control. In contrast with a DC speed
control system, the inverter drive and induction motor system are sensibly alike in price, can
handle higher speed, and are more vigorous. Application that does not need high torque at low
speed, for instance variable seed fans and pumps are good for the closed loop drive. [18].
The voltage and frequency output of a driver will be separately variable. With such convenient
voltage and frequency, it is likely to achieve a high competent speed controlled for the induction
motor. The only deliberation will be the torque on the shaft, due to if the voltage supplementary
to the motor changes, the frequency also has to vary to make sure torque on the shaft which
means, if the ratio between voltage and the frequency is kept stable, the torque also stay steady.
The restriction will be that the output voltage will not surpass the supply voltage, and the
frequency is controlled within the abilities of the transistors that will be used. The base speed of
Muhammad Nasir
Speed Control of Induction Motor
9
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
a straight connected motor will for eternity is at supply voltage and frequency, except the value
for the drivers are configures to attain a batter result. The function and operation of the inverter
drives that can attain such control of the induction motor, is explained in hardware chapter. [18].
Close loop driver feedback is shown in figure below.
Motion controller
Motion Driver
Motion Device
Figure2. 6: Close Loop Drive Feedback [18].
Muhammad Nasir
Speed Control of Induction Motor
10
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
3: Hardware
In chapter 2, some of the background theory is discussed; in this chapter hardware part of the
project is discussed in detail.
The hardware used in project is listed below.
1. IRAMS10UP60A Power Module
2. 6 X ^N137 Optocouplers
3. LTS 15-NP Current Sensor
4. Boot Strap Capacitors
5. DC Bus Capacitors
3.1 International Rectifier Actives-and-Passives (IRAM)
International Rectifier Actives and Passives or IRAM is integrated power module and is use for
the motor control of variance types. The module used for this project is IRAMS10UP60A. It has
very simple design to control the AC motor. This component is design to derive the AC motor so
this is why this component is chosen for this project. [10].
The IRAM also have built in system that is for temperature control. It means it has built in
system that is capable of defense against the overload temperature and current. Another
advantage of IRAM is its design is simple and it gives IRAM low cost. This is the one of the
biggest advantage. [10].
IRAM is also effective for tronic control in purposes such as washing machines and refrigerators.
Other features are as fallowing.
1. Integrated Gate Drives and Bootstrap Diodes
2. Temperature Monitor
3. Temperature and Over-current shutdown
4. Fully Isolated Package
5. Low VCE (on) Non Punch through IGBT Technology
6. Under-Voltage lockout for all channels
7. Matched propagation delay for all channels
8. Low side IGBT emitter pins for current control
9. Schmitt-triggered input logic
10. Cross-conduction prevention logic
11. Lower di/dt gate driver for better noise immunity [10].
There can be observed from figure 3.1 above that VSI and driver are made into the
IRAMS10UP60A. The main power supply to the VSI is linked among pin 10, and pin 12, 13, 14.
Pins 12, 13, and 14 are connected with each other as each pair of transistor goes to the same
ground from the main power supply. The three phases of output to the motor goes out from pins
2, 5 and 8, pins 1, 4, and 7 are the high side floating supply voltage. Pins 15, 16 and 17 are the
logic input side gate drivers for each of the three phases and pins 18, 19 and 20 are the logic low
Muhammad Nasir
Speed Control of Induction Motor
11
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
side gate drivers for each of the three phase. These are the input signals which come from the
DSP Pin 21 is the temperature check and shutdown pin. This pin will connect to ground. Pin 22
is the main supply to the IRAMS10UP60A which has a 15V power supply connected. Pin 23 is
the negative main supply which connects to the ground. [10].
3.2 6N137 Optocoupler
An Optocoupler is a device that operates a short optical transmission path to pass a signal
between components of circuit, in general a transmitter and receiver, while holding them
electrically isolated, since the signal pass from an electrical signal to an optical signal back to an
electrical signal, electrical contact along the path is broken. [11].
The 6N137 optocoupler needs to be used in this circuit because the IRAM needs to be
electronically isolated from the rest of the circuit. Therefore this can prevent any back emf going
into IRAM. [12].
The 6N137 is single channel optocoupler. A figure for this can be seen below.
Figure3. 1: 6N137 Optocouplor [13].
As shown in figure 3.2, there is 850nm AlGaAs LED connected between pins 3 and 2, this is
optically coupled to very high speed integrated photo detector logic gate which has storable
output. And open collector is active at this output and this will allow wired OR outputs [12].
The applications for 6N137 are listed below.
1. Ground loop elimination
2. LSTTS and TTL, LSTTL or 5-vold CMOS
3. Line receiver, data transmission
4. Data multiplexing
5. Switching power supplies
6. Pulse transformer replacement
7. Computer peripheral interface [12].
Other components connected around the 6N137 are shown in figure below.
Muhammad Nasir
Speed Control of Induction Motor
12
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Figure3. 2: Components connected with 6N137
As shown in figure, there is a 100nF capacitor among pin5 and pin 8, there is a 1kΩ resistor
connected among pin6 and pin 7 too. Pin 7 and pin 8 are also connected with each other. Pin 8 is
the 5V input and pin 5 is grounded. So the connections are prepared in order to divide this part of
the circuit. Pin 2 is input from the ADMC 330 output. There is 180kΩ resistor connected among
ADMC 330 and 180kΩ. This resistor is applied in order to control the current going into the
6N137. Pin 3 set to ground; this ground however is to be different from the ground from the pin
5. This is because the purpose of the 6n137 is to separate the IRAM from the rest of the circuit.
So this consequently means that the ground on both sides of the 6N137 have to be different. Pin
1 and pin 4 have no internal connection.
3.3 Current Transducer LTS 15-NP
The LTS 15-NP current sensors used to calculate the current across the one of the three phases
that is input into the induction motor. Two of the three phases need to be calculated for this
project, therefore two of the LTS 15-NP required to be used. [14].
The features of the LTS 15-NP are as fallowing.
1. Closed loop multi-range current transducer using the Hall effect.
2. Uni-polar voltage supply
3. Compact design for PCB mounting
4. Insulated plastic case recognized according to UL 94-V0
5. Incorporated measuring resistance
6. Extended measuring range. [14].
The advantages using current sensor is that it has excellent accuracy, very good linearity, very
low temperature drift, optimized response time, wide frequency bandwidth, no insertion losses,
high immunity to external interference and current overload capability. [14].
Applications where current sensor used are AC variable speed drivers and servo motor drivers,
static converters for DC motor drivers, battery supplied applications, uninterruptible power
supplies (UPS), and switched mode power supplies (SMPS) and power supply for welding
applications. [14].
The structure of the LTS 15-NP is shown below.
Muhammad Nasir
Speed Control of Induction Motor
13
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Figure3. 3: internal structure of LTS 15-NP. [14].
By using the LTS 15-NP, the current of the two of the three phases can be calculated. In order to
achieve this voltage from the output pin was calculated. Then using the graph for the output
voltage versus the main current as seen the figure 3.5 below can be calculated. As an instance of
the output voltage is 4.5 volts, the main current will be at its utmost value.
Figure3. 4: Graph form output voltage of sensor [14].
The current sensors are not useful for this project. They are placed for future enhancement.
3.4 Boot-Strap Capacitors
Across each of the three phases boot-strap capacitors must be connected. The values of these
depend on the switching frequency to be used. It is shown in graph below
Muhammad Nasir
Speed Control of Induction Motor
14
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Figure3. 5: Recommended minimum Boot-Strap Capacitors Vs Switching Frequency. [10].
The switching frequency to be used for this project is 20 KHz. So as can be seen in figure above
the utmost capacitance that can be used in 2.2μF. Though, because of the frequency being high
the capacitance can be abridged slightly, thus 1μF capacitor can be use.
3.5 DC Bus Capacitors
DC bus capacitors require to be connected among the positive bus input voltage and the low side
emitter connections which is ground. An electrolytic capacitor should be connected as close to
the pins as possible. The value of this is 1 mF. The capacitor should also survive voltage up to 40
V as this is highest voltages to be used at this terminal. A ceramic capacitor has to be also
connected in the similar approach parallel to the electrolytic. It will cancel the power supply
noise due to switching of digital operation. The value of the ceramic capacitor is 100 nF. [10].
3.6 Maxin Low Power 8 Channel Serial 12 Bit ADC
The MAX186/MAX188 is 12 bit digital to analog converter an 8 channel multiplexer, high
bandwidth track, and serial interface as one with high conversion speed and especially low
power consumption. The device works with a single +5V supply or dual ±5V supplies. The
analog inputs are software configurable for uni-polar/bipolar and single ended/differential
operation. Its operating frequency for software frequency is 100 KHz to 2 MHz. the required
frequency for intended application is 20 KHz. [15].
The MAX186.MAX188 uses one and the other internal clock or an external serial interface clock
to do successive approximation A/D conversions. The serial interface can function further than
4MHz when the internal clock is used. [15].
The MAX186/MAZ188 provides a hard wired SHDN (Three-Level Shutdown Input) pin and
two software selectable powers down modes. Admittance the serial interface automatically
powers up the device, and the quick turn on time permits the MAX186/MAX188 to be shut
down among each conversation. Using this method of powering down between conversions,
supply current can be cut to under 19μA at reduced sampling rates. [15].
Muhammad Nasir
Speed Control of Induction Motor
15
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
The features are as listed below.
1. 8 channel single-ended or 4 channel differential inputs
2. Single +5V or ±5V operation
3. Low power
4. 1.5mA (operating mode)
5. 2μA (power down mode)
6. Internal Trach/Hold 133KHz sampling rate
7. Internal 4.096V reference (MAX186)
8. SPI, QSPI, Microwire, TMS320-compatible 4 wire serial interface
9. Software configurable unipolar or bipolar inputs
10. 20 pin DIP, SO, SSOP packages
11. Evaluation kit available [15].
Its applications are Portable Data logging, data acquisition, high accuracy process control,
automatic testing, robotics, battery powered instruments and medical instruments [15].
3.7 ADMC-330
Figure3. 6: ADMC-330
One of the main hardware unit used for this project is the ADMC 330 DSP micro controller
product of Analog Devices. It is a single chip DSP based motion control unit that is specially
made for high performance control of AC induction motor and other a variety of motors. The
unit can be divided into three parts. [16]
1. The ADMC-330 Motion Control Processor
2. The ADMC-330 Evaluation Board and connection board
3. The Motion control debugger software application wizard [16].
These features are briefly described below in this chapter. It gives the overview of the
architecture of the ADMC-330 processor, and its fundamentals functionality. With relation on
how the processor interacts with the connection board and the ADMC application software
Muhammad Nasir
Speed Control of Induction Motor
16
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
3.7.1ADMC-330 Motion Control Processor
The ADMC-330 consists of high speed numeric processing application which makes it optimum
its software, hardware and instructions, Makes it necessary for the processing of digital data
representation with regards to analog signal in real.
The ADMC-330 microcontroller DSP was selected for this project as of the combination of
reasons. Such as its grouping of design elements: the arithmetic operation, the memory
management, instruction set and the addressing gives major advantages. For example, the real
time signal comes to the DSP as a train of individual samples from an analog to digital converter
(ADC). Though in order to perform filtering in real time, the DSP has to total all the necessary
calculations and operations necessary for processing each sample ahead of the next sample
arrives. Thus it fulfill such high frequency calculations operating fast adequate by the processor,
in order to synchronies the chain of operations it is responsibility in real time. This is only
achievable due to the highly adapted DSP processor because an average processor cannot do
such calculations in short time. [16].
ADMC-330 put together a 20 MHz fixed-point ADSP2171 core and a complete set of motor
control peripherals. The DSP core, which is totally code friendly with the ADSP 2100 DSP
family, includes of three computational, units, data address generator (DAG) and a program
sequencer. The three computational units are an arithmetic logic unit (ALU), amd
multiplier/accumulator (MAC) and barrel shifter. [16].
The ADMC-330 contains 2K x 24 bit program memory random access memory (RAM), 2K x
24-bit program memory read only memory (ROM) and 1K x 16bit data memory RAM. The
program and data memory RAM can be boot loaded from the serial port from either a serial
ROM/EEPROM. Additionally to its capability to boot load off a serial ROM, the ADMC-330
motor controller can be boot loaded from an external device configuration as s standard
Universal Asynchronous Receiver Transmitter (UART). [16]. the external device must permit
the ADMC-330 time to go through its power-up/reset sequence and must stick to a given
command protocol uttered by the ADMC-330 monitor program which execute out of chip ROM.
The program memory ROM comprises a monitor that attaches software debugging features
inward the serial port and a number of per-programmed motor control and mathematical
functions are included in the program memory ROM. The motor control peripheral contain a
high performance five channel Analog to Digital Converters system that uses sigma-delta
conversion technology, which is necessary for exactitude application. Each ADC channel to be
configured as a differential or single-ended input is required for precision application. Each ADC
channel can be configured as a discrepancy or single ended input for utmost elasticity in
interfacing to external sensor and inputs. For each channel, a classic signal to noise ratio of 76
Db may be attained, which is equal to 12 bits of resolution form each converter. [16].
In addition, a 12 nit center based PWM is equivalent to 12 bits of resolution from each converter
[16].
For a 3-phase power inverter, the ADMC-330 has a lithe 12 programmable inputs and outputs
interface that can be used for position sensor feedback. They can also be independently
configured for an interrupt source or as PWM trip source [16].
Muhammad Nasir
Speed Control of Induction Motor
17
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
3.7.2 ADMC-330 Architecture
Figure3. 7: ADMC-330 Architecture View. [16].
If the above figure the architecture view of the ADMC-330 is shown. This picture shows its
architectural setup, in relative to other peripherals with the ADMC-330 evaluation board. It is
based on the ADSP 2171 architecture and an inclusive instruction set, which permits the
processor to execute multiple operations in parallel. The processes enclose three independent
computational units, the MAC, ALU and shifter. The computational unit process 16-bit data, and
also maintains multiprocessing of operation. The ALU do a standard set of arithmetic and logic
operations even primitives divisions are supported. The MAC performs a typical set of arithmetic
and logic operations even primitives divisions are sustained. The MAC performs operations for
instance single cycle multiplication, multiply/add and multiply/subtract with an accretion of 40
bits. Even as the barrel shifter do logical and arithmetic shifts, normalization, and demoralization
and derive supporter operation. The shifter can be used to competently execute numeric format
control together with floating point representation as well. [16].
The program sequencer and two DAGs (Data Address Generators 1 and 2) make sure wellorganized delivery of operands to the computational units. The two DAGs also present address
for concurrent operand fetching from data memory and program memory. Every DAG maintains
and updates four address pointers inside the instructions registers and when pointer is used to
access data, it is post customized by the value in one of four modify registers. [16].
To execute an automatic modulo addressing for circular buffers, a length value can be linked
with each pointer. DAG1 generates only data memory address and has elective bit reversal
ability.
Data can be transferred efficiently with the use of following internal buses as listed below.
Program Memory Address (PMA) Bus
Muhammad Nasir
Speed Control of Induction Motor
18
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
1. Program Memory Data (PWD) Bus
2. Data Memory Address (DMA) Bus
3. Data Memory Data (DMD) bus
4. Result (R) Bus [16].
Within a single cycle, the ADMC-330 can obtain two operands, one from the program memory
and other from the data memory. It can also gather the on chip program memory and to fetch the
next instruction to be executed. The ADMC-330 writes data from its 16-registers to the 24-bit
program memory using the bus exchange. The ADMC-330 can respond to a number of explicit
DSP core and peripheral interrupts. The DSP core interrupts have serial port receive and transmit
interrupts, timer interrupts, software interrupts and external interrupts. The motor control
peripherals moreover produce interrupts to DSP core. A programmable interface counter is
furthermore included in the DSP core and can be used to generate periodic interrupts. The
ADMC-330 instruction set makes available a flexible data movement and multifunction
instructions. [16]
3.7.3: Functionality
The functional block diagram is shown below.
Figure3. 8: ADMC-330 Functional Block Diagram. [16].
The architectural setup of the DSP core of the ADMC-330 is highly well-organized, in the
implementation of its functions and operations, attached with the speed the process takes out its
command and instruction, the processor is capable to carry out the subsequent functions within
one cycle of operations that is 50 naon seconds.
1. Generate the next program address
2. Obtain the next instruction
3. Perform one or two data moves
4. Update one or two data address pointers
Muhammad Nasir
Speed Control of Induction Motor
19
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
5. Perform a computational operation
6. Receive and transmit data through the two serial ports
7. Decrement the timer [16].
The peripheral blocks can separately carry out the subsequent conditional upon the configuration
and program instructions set.
1. Generate three phase PWN waveforms for a power inverter
2. Generate two signals using the 8 bit auxiliary PWM timers
3. Acquire four analog signals
4. Control eight digital !/O lines
5. Decrement the watchdog timer. [16].
3.8: ADMC-330 Evaluation Board
The ADMC-330 Evaluation Board is a plug in extension for any proper motion control process,
is usually used for a simple initial development platform. It allows easy access to all applicable
input and output signals of the processor chip, via suitable connectors and terminal block. [16].
The Board is a dense, extremely integrated evaluation and software development platform for the
ADMC-330 microprocessor. This board permits user to test program coded application in real
time. It permits access through a UART connection to the motion control debugger software that
operates beneath window. This motion control debugger software is used for numerous
functions, to download executable code, observe the contents of registers, program memory and
data memory, run exactable modules, set breakpoints and enable single step operations. [16].
This board is capable of operating in a standalone mode with an appropriate power supply
voltage and either UART connection to the MCD or a suitable serial memory device. The board
also provides easy interface t the power inverter allowing a complete development of motor
control solutions. [16].
The following are the main features of ADMC-330 Evaluation Board.
1. 10 MHz crystal to give the CLINK frequency
2. Power on reset circuit gives a reset signal to the ADC-300 and UART
communication port.
3. A socket for a serial memory device ROM or EEPROM that can utilized for serial
boot loading for individual operation.
4. An optically isolated UART interface to the MCD.
5. An on board 5V-5V DC-DC converter that supplies an isolated 5V supply for the
UART interface circuit.
6. Analog interface circuit that equalize the analog input signals to the ADC inputs
of the ADMC-330
7. Digital expansion connector that allows up to 24 digitally input/output (I/O) lines
from the ADMC-330 motor control.
8. Analog input connector allows connection of up to 12 analog inputs that are
straight fed to the analog interface circuitry of the suitable processor board.
9. PWM output connectors allocate the six PWM output signals from the DSP to the
terminal block. PWM trip signal moreover accessible from this connector.
10. Analog output connector that gives eight analog outputs from a serial digital to
analog converter (DAC)
Muhammad Nasir
Speed Control of Induction Motor
20
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
A 25 way D-type connector that connects the serial port pins from the processor to the
connector. [16].
The block diagram of ADMC-300 Evaluation board is shown below.
Figure3. 9: ADMC-300 Evolution Board. [16].
In sequence to generate balance three phase sign triangle PWM outputs that will be used to drive
the induction motor with simple V/F control, Some simple hardware alterations are required on
the ADMC-330 evaluation board. These modifications are as following.
1. Capability to provide an analog voltage to analog voltage V1 (input to ADC1 of
the ADMC-330, should attain by using a potentiometer
2. Two pole RC filters should apply at the outputs of the auxiliary PWM outputs.
3. 300-pF ADC timing capacitor should be positioned at jumper JP6 of the ADMC330evaluation board. For a PWM switching frequency of 10 kHz, this will
provide the necessary saw tooth ADC reference voltage from 0 to 3.5V. [16].
Muhammad Nasir
Speed Control of Induction Motor
21
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
3.8: Voltage Source Inverter
The main functionality of the VSI (Voltage Source Inverter) convert DC signal into AC that can
then drive the motor. This is the technique must be achieved when working with speed control.
The circuit consists of six transistors. These transistors operate as switches. The output is threephase so for each one of them, there is a high switch and a low switch. Only one of these
switches can be switched on at any time, so if T1 (transistor 1) is on then T4 (transistor 4) must
be off and vice versa. An anti-parallel diode is also linked across each switch. This diode is
linked in this approach that when the switch is open the current can flow in the opposite
direction. So it can be seen that these perform as non-interventionist diodes, so this avoid
transient overvoltage. A DC voltage source (Vs) is supplied to the circuit. So from each pair of
switches there is an output phase, means these three phases can be also star connected or delta
connected, thus the switches can be used to generate a graph that can be controlled. As it is
discussed above, T1 and T4 are been used, subsequently as T1 is high switch and T4 is low
switch this can generate a step waveform, thus the timing of, when each switch is switched on
and off, can be controlled. So by doing this the mean waveform can be controlled, thus the
voltage amplitude and time period can be controlled.
By using the equation:
𝑓=
1
𝑇
Equation 3.1: Calculation of Frequency
The frequency can be calculated. Therefore the voltage and frequency can be controlled.
Typical ideal VSI is shown in figure below.
Figure3. 10: Ideal Voltage Source Inverter. [19].
Muhammad Nasir
Speed Control of Induction Motor
22
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
The output of the VSI is shown in figure 3.11 below.
Figure3. 11: Output if Voltage Source Inverter (VSI)
The result shows the digital output from the inverter. This result is not good because there are 3
1KΩ resistances are missing that should be connected in star configuration.
Muhammad Nasir
Speed Control of Induction Motor
23
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
4: Software
This chapter will describe the software phase of the project. The software part of the project is
not completed as it takes lot time to generate new code. The explanation on this section is based
on what the program should do.
Some of the important information needs to be discussed before describing the software.
4.1: Pulse Width Modulation (PWM) Concepts
Pulse width modulation (PWM) of a signal engages the modulation of its duty cycle to transmit
information over a communication channel or control of power transmits to a load. [22].
The power device switching signals are typically has fixed frequency PWM timing signal with
frequencies varying from a few thousands hertz to tens of thousands hertz. There are large
ranges of possible PWM methods varying from signal edged PWM, center base PWM, to
schemes with asymmetric PWM wave forms optimize to reduce harmonics or switching losses.
[23].
Still the most universally accepted PWM schemes are single edged or center based PWM. The
signal ended PWM scheme has the benefit of ease in implementation for the motor current
waveform acquisition system. [24].
The PWM generator on the DSP microcontroller gives three phases canter based, dead time
adjustment, PWM signal coordinated to the DSP clock signal. The PWM hardware contains both
waveform calculation and timing function so in that order three pairs of waveform can be
generated based or three register updates per PWM cycle, with no more additional processor.
The configuration option has individual output enable selection, a polarity control pin, and a gate
drive features. The six outputs can be directly connected to the gate drive amplifiers of the power
inverter. The duty cycle is controlled by three PWM channel register. [24].
A model set of PWM waveform, as shown in figure below, explains some of the features of the
PWM generator on the microcontroller. The PWM switching frequency, dead time and gate
drive modulation selections are selected by writing to the configuration register. In this case, the
high side gate drive circuit is transformer isolated so that signals are chosen in hardware by
setting the polarity pin to high. The PWM duty cycle for each inverter leg is selected by the
value in the PWM channel register. The software furthermore required to produce these
waveforms contains write operations to four PWM configuration register and three writes the
PWM duty cycle register every PWM period. [24].
The ADMC-330 is an independent programmable waveform generator that generates PWM
switching signals for a three phase inverter. It have a waveform timing edge calculation unit,
which the produce of six center based PWM signals, only three duty cycle register updated every
switching cycle. Hence, redesigning the DSP software which will be obligatory to control this
Muhammad Nasir
Speed Control of Induction Motor
24
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
PWM controller and freeing space for the processor time to perform other checks and command
steps.
Figure4. 1: PWM waveform example [24].
4.2: Serial Parallel Interface
The processor has an SPI well-matched port that allows the processor to communicate with many
SPI compatible devices. [21]
The SPI interface uses three pins for shifting data, two data pins and a clock pin. An SPI chip
select input pin allows other SPI devices pick the processer, and seven SPI chip select output
pins allow the processor select further SPI devices. The SPI select pins are reconfigured
programmable flag pins. By these pins, the SPI port gives a full duplex, synchronous serial
interface, which maintains both master and slave methods and multi-master settings. [21]
The SPI port’s transmission rate and clock phase/polarities are programmable, and it has an
integrated DMA controller, can be configured to carry both transmits or receives data stream.
The SPI’s DMA controller can only service only in one direction accesses to any given time.
[21]
Throughout transfer, the SPI port concurrently transmits and receives by serially changing data
in and out of its two serial data lines. The serial clock line matched the changing and sampling of
data on the two serial data lines. [21]
Muhammad Nasir
Speed Control of Induction Motor
25
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
4.3: Flow Charts
The flow chart of mail program is shown below.
Figure4. 3: Main Flow Chart
Main loop should initialize the ADMC and PWM communication. Then it should call the read
ADC function that should read the values. Then it should call the V/F subroutine. There should
be type casting between the Read ADC and V/F subroutine. Then it will initialize the values to
PWM unit. This is general overview of the software. The software is divided into several
Muhammad Nasir
Speed Control of Induction Motor
26
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
subroutines describes below. The reason behind dividing the software into parts so
implementation should be easy and testing should also be easy.
The flow charts for the subroutines are described below.
4.3.1: BF ADC Initialization
Flow chart is shown below.
Start
Send
Sample
Frequency
Set up
Interrupt
End
Figure4.3. 1: ADC Initialization Flow Chart
The BF should send sample frequency to the ADC and set up interrupt. By using that interrupt
ADC will come to know that sample frequency is send.
Muhammad Nasir
Speed Control of Induction Motor
27
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
4.3.2: ADMC ADC Initialization
Flow chart is shown below.
Start
Receive
Sample
Frequency
Set up
Interrupt
End
Figure4.3. 2: ADC initialization Flow Chart
When ADC should receive the interrupt, if will call the ADC initialization subroutine for ADC.
ADC should receive data and will generate interrupt.
4.3.3: PWM Initialization
Flow chart is shown below.
Muhammad Nasir
Speed Control of Induction Motor
28
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Start
Send
PWM
Send
PWM DT
Send
PWM PD
End
Figure4.3. 3: PWM initialization Flow Chart
When ADC receives the interrupt, it should initialize the PWM unit. It should initialize the PWM
Dead time control register (PWMDT); also it should initialize the PWM Pulse Width (PWMPD)
register.
Muhammad Nasir
Speed Control of Induction Motor
29
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
4.3.4: PWM Initialization
Flow chart is shown below.
Start
Receive
PWM
Receive
PWM DT
Receive
PWM PD
End
Figure4.3. 4: ADC Initialize (ADMC) Flow Chart
The initialization should configure various register to have correct PWM signal through the six
outputs from the ADMC-330 board. The six outputs are produced by the PWM generation block
of the ADMC-330. It should also work out with the PWM Dead time and PWM pulse width
control register.
Muhammad Nasir
Speed Control of Induction Motor
30
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
4.3.5: ADC Read
Flow chart is shown below.
Start
Check for
Comm.
Process
Comm. Process
Active
No
Call Init.
ADC
Yes
Read ADMC
Date
A=ADC data х Angle Coefficient
∆θ= ADC data × ∆θ Coefficient
End
Figure4.3. 5: ADC Read Flow Chart
At the start, this function will check the communication process. After setting the connection, it
should read the ADC data. This subroutine should produce the ∆θ coefficient by multiplying the
ADC data and angle coefficient.
4.3.6 ADC Read
Flow chart is shown below.
Muhammad Nasir
Speed Control of Induction Motor
31
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Start
Check for
Comm.
Process
Comm. Process
Active
No
Call Init.
ADC
Yes
Receive ∆θ
Coefficient
Receive PWM Data
Set PWM Unit
End
Figure4.3. 6: ADC Read Flow Chart
This subroutine will receive the ADC data after checking the connection process. The value it
should receive is ∆θ coefficient. It should then initialize that value for PWM.
Muhammad Nasir
Speed Control of Induction Motor
32
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
4.3.7: ADC Write
The Flow chart is shown below.
Start
Initialize Comm.
Protocol
ADMC
Ready
No
Error
Connection
Yes
Read
Amplitude
and angle
No
Connection Error
Phase A = A × Sin (θ)
Phase A = A × Sin (θ × 120 )
A = A × Sin (θ × 240 )
Yes
Set Flag
Send Amplitude and Angle
to ADMC PWM
Update θ
Figure4.3. 7: ADC Write Flow Chart
This is important subroutine. This subroutine will check the connection. After setting the
connection it should read the amplitude and angle from. Then it should produce the three phase
waves. It should use the amplitude and angle that it obtains and using the math functions, and
giving the phase difference of 120 degree in angle, it should produce the three phase sign wave.
Muhammad Nasir
Speed Control of Induction Motor
33
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
4.3.7: ADC Write
The flow chart is shown below.
Start
Initialize Comm.
Protocol
Connection
Ready
No
Error
Connection
Yes
Receive
Amplitude
and angle
Update PWM
No
Connection Error
Yes
Set Flag
End
Figure4.3. 8: ADC Write Flow Chart
After setting the connection, ADMC will receive the information of angle and amplitude and
update that information to PWM unit.
4.4: Discussion
Muhammad Nasir
Speed Control of Induction Motor
34
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
The ADC data is interpreted at the PWM rate therefore the PWMSYNC interrupt is used. The
value is used to calculate the angle of signal. The PWM is matched to the DSP core by clock,
which passes half the DSP clock frequency giving waveform resolution. There are four registers,
which describe basic waveform parameters are the master switching (PWMTM), dead time
(PWMDT), minimum pulse width (PWMPD) and gate drive chopping (PWNGATE); by the
output signals controlled by the input register PWMCHA, PWMCHB, PWMCHC and
PWMSEG.
One of the timing register, which is the dead time adjustment, is also essential in the switching
pattern of transistor set for each phase, as it is the delay time between from ON in the one wave
form and OFF for the another waveform. For example AH to being ON in the completely
waveform though for any pulse that is very close as compared to the value in the timing register
the pulse should be removed and not generated as the function of the deletion register. This
function is necessary to avoid of uneven pulse width by setting the least satisfactory pulse width.
The BF 533 should connect with ADMC 330 with serial parallel interface that BF 533 have. The
connection should take place that when BF533 should initialize its port, there should be a check
at that place that should try to connect with ADMC-330.when the BF-533 connect with the
ADMC-533, it will wait for the data that is the ADC data from the ADMC-300. After receiving
ADC data from ADMC-330, the BF-533 will generate the three phase sinusoidal signal and
should send the amplitude and angle of the signal to ADMC-300 PWM unit. The ADMC-330
should read the PWM data from BF-533 and set the PWM unit.
As it can be known that the generation of the three phases supply voltage is dependent upon the
generation and control of the PWM waveform. In this project, the three phase signal is being
produced in the DSP microprocessor, and from the PWM block channel, which is the fed into
power inverter. The three phases can be shown in the form of equation below.
𝐴 = sin⁡(𝜔𝑡)
2𝜋
𝐵 = sin⁡(𝜔𝑡 + )
3
2𝜋
𝐶 = sin⁡(𝜔𝑡 − )
3
Equation 4.1: formulas for Three Phase Generation from DSP
Where the change in voltage is shown 120˚ change. These three phases can be used straight in
this simple three phase generation as control voltage for the frequency converter with sinusoidal
reference.
5: Conclusion and Future Work
This chapter will discuss the overall progress made in this project and future work for this
project.
Muhammad Nasir
Speed Control of Induction Motor
35
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
5.1: Overall Progress
The project was divided into two parts, Hardware part and software part. Hardware part was
consists of building the power module circuit. The software part was writing the program for the
DSP to control the power stage of the whole system. Hardware part was completed and the
power module works 90%. When the power module was tested it works fine and as seen the
result in chapter 3, the graph obtained is not good, because there should be 3 1KΩ resistances
connected in star formation. If we neglect the three resistances in star topology, the rest of the
result is satisfactory.
The software part consists of writing the code for DSP to control the power module. This part is
not done because of lack of time. Although the paper work of software is done but software
building is not take place. The difficulty when working with this project was time management.
Time was short and soldering the hardware takes time. The other aspect was ordering and
delivering the hardware takes time. Most of the time spend was gathering the components,
building the components and testing them. It was also difficult to learn new tool and generate
new code for DSP within the given time. The lack of significant development with the
parameters of the program code also means that the objective of producing a sinusoidal
waveform for the control of the induction motor was not achieved.
Even though project is not completed successfully, but the experience gained through the
participation of this project is one of the achievement. The knowledge of motor control is gained
and also experience of time management is gained.
If the time management would be batter, there should be change to completion the tests on hard
and also there should chances to complete the software as well.
5.2: Future Development
There are several aspects of the project that can be further developed. The main subject is time
management and use of time cleverly. The hardware part required to be well planned.
It is suggested for the understanding of the programming structure, variables, constant and
permutation character. With this, good development could perform on an example code or the
generation of new code.
5.3: Suggestions
If someone else wants to do this project, there are some advices for him/her. Start the project
early. Order the components and learn about the tool you are going to use for software. Gather
all the information about your hardware components in single meeting and order them same
time. Management of time is very important. Plan your things carefully so you can do your
project in time and complete.
References
[1] R. Parekh, “AC Induction Motor Fundamentals”, http://www.industrialcontrols.eetchina.com
[2] http://www.britannica.com/eb/art/print?id=1398&articleTypeID=0
Muhammad Nasir
Speed Control of Induction Motor
36
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
[3] http://www.automatedbuildings.com/news/jul01/art/abbd/abbd.htm
[4] http://en.wikipedia.org/wiki/Induction_motor
[5] http://ieeeexplorer.ieee.org/iel5/2943/31382/01458276.pdf
[6] http://en.wikipedia.org/wiki/Inverter_%28electrical%29
[7] A. Felton, April 2007, “V/F Induction Motor Control System Based on ADMC-331”, project
report B.Eng.
[8] Mitra, sanjit K, 2006, Digital Signal Processing: A Computer-Based Approach, McGraw
Hill, New York.
[9] http://www.analog.com/en/prod/0,,ADSP-BF533,00.htm
[10] http://www.datasheetcatalog.org/datasheet/irf/irams10up60a.pdf
[11] http://en.wikipedia.org/wiki/Optocoupler
[12] http://www.fairchildsemi.com/ds/6N/6N137.pdf
[13] http://www.rapidonline.com/netalogue/zoomed/Large/58059801.jpg
[14] http://www.vernk.com/Documents/LaunchController/LTS_15-NP_CurrentTransducer.pdf
[15] http://pdfserv.maxim-ic.com/en/ds/1070.pdf
[16] ADMC 330 DSP Microcontroller Reference Manual (www.analog.com/motorcontrol)
[17] http://www.analog.com/library/analogDialogue/archives/31-3/Powerful.html
[18] Kely. C, April 2003, “Motion Control System Using ADMC 300”, (www.plato.herts.ac.uk)
[19] http://en.wikipedia.org/wiki/Image:3-phase_inverter_cjc.png
[20] http://en.wikipedia.org/wiki/Inverter_(electrical)
[21] http://www.analog.com/static/imported-files/processor_manuals/892485982bf533_hwr.pdf
[22] http://en.wikipedia.org/wiki/Pulse-width_modulation
[23] Lucey, D.J, Roche, P.J., Harrington, M.B. and Scannell, J.R. "Comparison of various space
vector modulation strategies" Proceedings Irish DSP and Control Colloquium, July 1994, Dublin
Ireland, pp. 169-175
[24] Aengus Murray and Alessandra Margio, Analog Devices, Motion Control Group,
Wilmington, MA 01887
Muhammad Nasir
Speed Control of Induction Motor
37
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Appendix 1
The internal structure of the IRAM can be seen in the figure below.
Muhammad Nasir
Speed Control of Induction Motor
38
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Figure 3.1: International Rectifier Actives and Passives (IRAM) [10]
Muhammad Nasir
Speed Control of Induction Motor
39
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
The pin configuration is shown below in figure.
Figure 3.2: IRAM Pin configuration.
Muhammad Nasir
Speed Control of Induction Motor
40
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
Typical circuit Diagram for Voltage Source Inverter
Figure: typical Circuit Diagram for VSI.
Muhammad Nasir
Speed Control of Induction Motor
41
School of Electronic, Communication and Electrical Engineering
M.S.c. Final Year Project Report
ADMC 330 Pin Configuration
Figure 3.7: Pin Configuration 80 Leads Plastic Thin Quad Flat pack [16]
Muhammad Nasir
Speed Control of Induction Motor
42