Application of MATLAB/SIMULINK and PSPICE Simulation in Teaching
Power Electronics and Electric Drive System
1
2
Tao Zhao1, Qunjing Wang2
Department of Automation, Anhui University, Hefei 230039, China
School of Electrical Engineering & automation, Hefei University of Technology, Hefei, 230009 China
Abstract—Nowadays computer simulation has been an
important tool in teaching. In this paper, MATLAB
/SIMULINK and PSPICE are used to deepen the
undergraduate students understanding of power electronics
and electric drive system. The RCD snubber circuit, DC/AC
three-phase inverter circuit and the vector control system of
induction motor are been designed and analyzed using
PSPICE and MATLAB/SIMULINK respectively. The
performance of various designs are tested by plotting the
current, voltage, speed response and other waveforms using
the graphics postprocessor Probe and MATLAB workspace.
The examples can be implemented in class and in class
projects or undergraduate design projects. The response was
positive.
Key words—Education technology, power electronics,
electric drive system, MATLAB/SIMULINK, PSPICE
I. INTRODUCTION
The power electronics and electric drive system is one
of the most important fundamental courses for
undergraduate student of electrical engineering and
automation major. Teaching a course in power electronics
and electric drive system is, however, challenging, since
the field is quite broad and includes fundamentals from a
wide variety of areas of engineering. These areas include,
but are not limited to, control systems, electromagnetics,
semiconductor devices, electric machinery and digital
signal processing. On the other hand, compared with past,
owing to the increasing courses for the students, teaching
time of every course is reduced. In order to overcome this
challenge, the computer simulation has been an important
tool to simplify teaching and to introduce student to solve
real-world engineering problems. Students are allowed to
vary the circuit parameters and to examine the effect of
these changes on the electrical variables. This process is
equivalent to the creation of a virtual laboratory where the
computer screen replaces the oscilloscope in a real
laboratory environment.
Nowadays, a variety of software tools, such as
SABER, SIMPLORER, PSPICE, MATLAB, etc., is
available to simulate power electronics circuit and electric
drive system. Considering the follow some causes, the
MATLAB/SIMULINK and PSPICE are been used as
tools for the application of teaching power electronics and
electric drive system is this paper.
MATLAB/SIMULINK is widely used for the
simulation of almost all types of dynamic systems. This
software package is also valuable for teaching and
learning since it provides a series of standard routines and
software toolboxes, such as control toolboxes, system
identification blocks, and neural networks block set, etc,
which enable students to perform system simulation,
identification, and control. The Power System Blockset
(PSB) toolbox features electrical models of power
semiconductors and the most commonly used power
devices (machine, transforms, power lines, voltage
sources), and allows simulation of power electronics and
electric drive system [2]. The PSB is well suited to the
simulation of medium size power systems and power
electronics using variable or fixed step algorithms from
SIMULIK. The PSB libraries contain basic elements as
well as many ready-built sub-systems. Control system
using SIMULINK blocks can be naturally integrated into
the power electronics and driver system model.
Computation capabilities of MATLAB/SIMULINK can
be advantageously exploited in post-processing of
simulation results. Simulation results are displayed on
SIMULINK Scopes while the simulation is running.
Students can access a variety of MATLAB functions and
toolboxes for processing and plotting of waveforms stored
in the MATLAB workspace.
This paper is divided into two major sections as
follow: The first section is using PSPICE designing and
analyzing a RCD snubber circuit and three-phase DC/AC
inverter. All simulation described in this section are
completed by using the Microsoft™ Windows student
version 9.1 of PSPICE. The schematic capture facility is
used and a circuit schematic is developed for each design
using the graphical schematic editor as an input file to the
simulator. In second section, simulation and analyzing of
a vector control of induction motors drive system using
MATLAB/SIMULINK is given.
II. EXAMPLE BASED ON SPICE
PSPICE is a very popular circuit simulation program
of available device models and affordability. An
evaluation version of PSPICE is available to students
through Microsim Corporation. PSPICE outputs a text
and data file. The text file reports all the request results
and shows any errors that occur during simulation. The
data file is used as an input to the graphic postprocessor
program, a waveform analyzer knows as Probe [1].
PSPICE is well suited for device-level modeling of small
size systems: study of voltages and currents in power
converters, snubber circuit design, study of transformer
transients, etc. Also, PSPICE performs well for systemlevel modeling of small size power systems.
A. Snubber for Boost-buck Circuit
If a power electronic converter stresses a power
switch device beyond its ratings, there are two basic ways
2037
of relieving the problem. Either the device can be replace
with on whose ratings exceed the stresses or snubber
circuits can be added to the basic can be added to the
basic converter to reduce the stresses to safe levels. In
hard switching inducting inductive load circuits the di/dt
stress is severity especially. The snubber circuits are be
used to protect the switch device by improving their
switching trajectory.
A boost-buck converter with RCD snubber is used to
illustrate the approach, the boost-buck shown in Fig. 1, is
a DC to DC converter. The circuit consists of an insulated
gate bipolar transistor (IGBT) or other active switches, a
fast recovery diode, an inductor L1, a capacitor C1and a
load resistance Rload. A control signal is applied to the
active switch to turn it ON or OFF. After mastering the
basic idea behind the buck convert, students will be asked
to examine the effect of using RCD snubber circuit with
different parameters.
Fig. 1. Input schematic of Buck-boost converter with
RCD snubber circuit
Fig. 1 shows the input schematic file of the boostbuck converter. The design parameters are chosen to be
V=540V, L1=1H, C1=100uF, Rload=2.7 Ω , snubber
resistance Rs=10 Ω , Cs=2.0u, stray inductance
Lm=10uH.The active switch is modeled as a voltagecontrolled switch, the control signal is pulse signal, which
parameters are given in Table1. (Some parameters
selected above come from a real project that author have
been done.)
Fig. 2. Waveform of voltage and current
The presence of stay inductances results is an over
voltage since di/dt is negative.
Another important command found in PSPICE is
the .STEP command, which allows one to perform a
parametric variation analysis on all input parameters. For
example, students can investigate effect for different
snubber capacitor. Fig. 3 shows switch peak voltage for
different capacitor value.
Fig. 4 shows the waveforms of snubber resistance
current at different resistance value. The resistance value
should be chosen so that the peak current isn’t increase
stress of switch when switch turns ON. On the other hand,
the capacitor should have sufficient time to discharge
down to a low voltage. Rs is chosen using Eq.3. From the
Fig. 4, it is evident that it is usually better to reduce
transient voltage with improved power circuit layout and
/or snubber designs.
C S ∆ V CE2 max
L I2
= m
2
2
RS <
TABLE I
PARAMETERS OF PULSE SIGNAL
V1
-5V
V2
10v
Per
200us
Pw
100us
Tf
1us
Tr
2us
Now, students can observer the voltage and current
waveforms when switch turns ON or OFF. Fig. 2 shows
the waveforms of switch voltage, snubber capacitor Cs
charge, discharge current, and Rs current. The switch
voltage can be expressed as
vCE = V1 + VC − Lm
di
dt
(1)
2038
t on
2.3C S
Fig. 3. Vce Voltage for different snubber capacitor
(2)
(3)
Fig. 4. Current for different snubber resistance
Fig. 5. DC/AC inverter circuit
The modulation waveforms of SPWM and THIPWM
and triangular carrier are shown in Fig. 6
B. DC/AC Inverter Circuit
The three-phase DC/AC inverter circuit is shown in
Fig. 5, which includes control circuit, inverter and load. In
this example, students are interested in the pulse with
modulation (PWM) control technology. The PWM
method is based on the comparison of the modulating
wave with a triangular carrier waveform. The point of
intersection determines the switching points of the power
devices. In three-phase system, a common carrier can be
used for three phases. In this paper, the triangular carrier
waveform is generated from analog behavior modeling
(ABM) [2], the only one sinusoidal waveform is based on
signal source. The three-phase signal formula used as
follows:
⎧ u Ar = A sin( wt ) + B sin(3wt )
⎪
⎨u Br = A sin( wt − 120°) + B sin(3wt )
⎪u = A sin( wt + 120°) + B sin(3wt )
⎩ Cr
(4)
Where A, B is a constant, also is the amplitude of the
modulating signal. When A≠, B=0, it is Sinusoidal PWM
(SPWM), and when A≠0, B≠0 it is Third Harmonics
Injection PWM (THIPWM)
Now one is ready to implement the DC/AC inverter
using PSPICE. The schematic input file as shown in Fig.
5, six power MOSFET are used as switch, which
connected in anti-parallel with diode inside. The design
parameters used for the DC/AC inverter circuit are as
follows: V1=540VDC, Lx=25mH, Rx=2Ω and Ex=200V,
which x=1, 2, and 3.
The amplitude modulation ratio m is defined as
m=
Ar
Ac
Fig. 6. The waveforms of modulation and carrier
The output voltage and current can be investigated for
different parameters. Fig. 7 shows output phase voltage
and line to line voltage, at A=1.15 and B=0.19,m=0.8,
N=40.
Fig. 7. Output phase voltage and line to line voltage
Fig. 8 shows three-phase current at A=1.15 and
B=0.19, m=0.8 and f=100.
(5)
where Ar is amplitude of reference and Ac is amplitude of
carrier waveform.
The frequency modulation ratio f is defined as
f =
fc
fr
(6)
Fig. 8. Three phase output current
where fc is carrier frequency and fr is modulation
frequency.
From these waveforms, students can be encouraged to
investigate other PWM control methods.
2039
III. PSB SIMULATION OF A VECTOR CONTROL SYSTEM
ωs =
A. Modeling the Vector Control System
In this section, the PSB is introduced to analyze of the
vector control of an induction motors drive system. The
block diagram of the vector control of an induction
motors drive system is shown in Fig.8. The three-phase
IGBT inverter is modeled by a Universal Bridge block in
which the Power Electronic devices and Port
configuration options are selected as IGBT/Diode and
ABC as output terminals respectively.
The induction motor with a squirrel-cage rotor is as SI
unit model. The electrical and mechanical parameters of
the motor and load are chosen to be L-L voltage=380V,
rated frequency =50Hz, and other parameters: RS=0.087
Ω, LlS=0.8mH, rotor resistance Rr =0.228Ω, Llr=0.8mH,
LM=34.7mH, inertia J=1.66kgm2 and np=2.
The remains of the system, which includes the
hysteresis current regulator, the dq-abc converter, and PI
speed controller, is made up of standard SIMULINK
model. A flux control loop has been added for precision
control of flux. The torque component of current Iq * is
generated from the speed control loop. Fig. 9 can be
extended to flux weakening mode by programming the
flux command as a function of speed so that the inverter
remains in PWM mode.
The motor currents and speed signals utilized by
control system are provided by the measurement output of
the Asynchronous machine block.
Fig.9. Induction motor vector control block diagram with
speed and flux closed-loop control
B. Rotor Flux Vector Estimation
In the direct vector control method, it is necessary to
estimation the rotor flux component Ψ . The different
combination of signals, which can be measured, such as
current, voltage, and speed, is provided to acquire
different flux estimation models. In the low-speed region,
the rotor flux component can be synthesized more easily
with help and three-phase stator current. Three-phase
stator currents are converted via abc-dq converter, and the
torque component of current iq1 and the flux component
of current id1 are acquired. Using vector formula 7-8, as
follow:
ψ2 =
Lm
id 1
τ 2P +1
(7)
LM
τ 2ψ 2
iq1
(8)
where τ2=LR/ Rr.
The rotor flux component Ψ and slip speed ωs signals
are attained. Using formula 9, we can get flux phase
signal θ. Fig. 10 shows a flux estimation model.
θ = ∫ (ω m + ω s )dt
(9)
Fig. 10. Current model flux estimation
C. Simulation Results
When vector control of induction motor SIMULINK
model described above has been implemented, the
simulation can start. State-space formulation allows the
use of a wide variety of fixed step and variable step
algorithms available time step algorithms are usually
faster because the number of steps is less than with a
fixed time step method. However, for large systems
containing a large number of states and /or power
switches, it is advantageous to discretize the electrical
system and to use a fixed time step algorithm. The
simulation results are displayed on SIMULINK scopes
while the simulation is running. The students can access a
variety of MATLAB functions and toolboxes for
processing and plotting of waveforms stored in the
MATLAB workspace.
In this simulation test, A fixed time step TS=1us was
used, the load torque was a constant 40Nm, speed
reference of 150rad/s was set. The current regulator
hysterisis band is defined to be 10A. The drive operation
and waveforms agree well with theoretical predictions.
The SIMULINK model is useful for different studies on
the drive operation.
The response of the motor torque amplitude, stator
three-phase current, motor speed, and rotor flux linkage
are shown in Fig. 11.
In particular, the transient waveform of output line
voltage and current can be seen in Fig. 12.
IV. CONCLUSION
The implementation for designing and analyzing
power circuit and drive system used PSPICE of student
version and MATLAB/SIMULINK of version 6.5 was
described. The method was presented in power electronics
and electric drive system class, it helps students
understand theoretical concepts, and on the other hand,
students were asked to implement a different circuit and
system as their class project. The experiment received a
positive response.
2040
200
0
current(A)
500
400
0
0.5
1
1.5
? ? (s)
2
2.5
3
200
0
-200
-400
0
-600
-500
0
0.5
1
1.5
? ? (s)
2
2.5
0
0.5
1
1.5
? ? (s)
2
2.5
3
0
0.5
1
1.5
time(s)
2
2.5
3
1
2.01
2.02
2.03
2.04
2
2.01
2.02
2.03
2.04
2.05
2.06
2.07
2.08
2.09
2.1
2.05 2.06
time(s)
2.07
2.08
2.09
2.1
50
current(A)
0
2
3
1000
flux(wb)
speed(r/min)
600
Tl=40Nm
voltage(V)
torque(Nm)
400
0
0.5
0
-50
Fig. 11. Simulation of the starting of the induction motor drive
Fig. 12. Induction motor voltage and current waveform
The technique presented in this paper can be
extended to undergraduate design projects in power
electronics and electric drives system and other courses.
In order to minimize convergence problems and reduce
the run times, MATLAB/SIMULINK and PSPICE should
to be used to implement different types of experiments.
[3]
[4]
[5]
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2041
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