DOI 10.4010/2015.333
ISSN-2321 -3361 © 2015 IJESC
Research Article
April 2015 Issue
Enhancement Performance Z Source Inverter for Speed Control of an
Three Phase Induction Motor Drive
B.Naganvesh Reddy1, S.Radhika2
PG Research scholar1, Assistant Professor2
Department of Electrical & Electronics Engineering
Sathyabama University ,Chennai, India
naganveshreddy.banda@gmail.com
Abstract:
In this paper presents a Renewable energy resource controlled Z-Source inverter connected to three phase induction motor drive
used to control the speed and torque of motor. Z-Source inverter used for buck-boost energy conversion is implemented using
only passive elements, it effectively reduce the voltage stress across the capacitors in the impedance network only and increases
the stability of the system. By controlling the shoot-through duty cycle the inverter system, reduces the harmonics, increases
stability and output voltage range increases. It reduces loss, speed also easy to control. Simulations using MATLAB /
SIMULINK are carried out to verify the performance of the proposed controllers. The simulation and experimental results are
presented.
Keywords: Z-Source inverter, shoot-through methods, Induction Motor Drive
1 INTRODUCTION
For environmental protection and energy saving, fuel cell,
photovoltaic cell and super-capacitor can be engaged to
supply electric energy in the Electric vehicle, due to their
environmental friendly features. Recently from few years
using Renewable energy system the effective methods that
supplied into the utility grid have been paid much
awareness due to increase in fossil fuel prices and energy
demand boom. Among various renewable energy resources
such as solar, wind, tidal, geothermal, biomass etc., the
solar photovoltaic system being more attractive and
promising green resource because of its abundant
availability, safe resource, cost free and eco-friendly. The
solar photovoltaic (PV) modules directly converts the
light energy into the electrical energy. In order to
improve the efficiency and convert low voltage DC source
into usable AC source, the power electronics converters are
used to transform DC into AC.
The proposed circuit of a Z-Source inverter as shown in
Fig:1. Z-Source inverter a single-stage converter
performs both buck-boost energy conversions utilizing
LC-impedance network. This method is used to overcome
the shortcomings of the traditional voltage source and
current source inverters. This combined operation of the z
source inverter eliminates the need of a separate dc-dc
converter, thus reducing the cost and increasing the
efficiency of the circuit. This feature of the inverter
provides the elimination of dead time in the circuit, Thus
increasing the reliability and reducing the output distortion
of the inverter. Saying that the voltage across the capacitors
in the traditional Z source network with inverter is equal to
the input voltage which increases the volume and cost of
the capacitors used.
Fig.1 Block diagram of an Z-sources inverter
Fig.2 Circuit diagram of an Z-sources inverter with I.M
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The Z-source inverter can be used to feed the adjustable
induction motor drive system and it has better performance
and results as compared to the conventional VSI. The Zsource inverter is also implementable to grid connected PV
system, which is transformer less and has low cost. ZSource Inverter (ZSI) with Solar Power Generation System
for feeding static as well as dynamic load (induction motor
drive) is proposed and implemented for remote area and
rural areas. In this topology, the explaining the
conventional VSI is replaced by a ZSI. The Z-Source
inverter employs a distinctive impedance network attached
with inverter circuit. The ZSI have recently been proposed
as an alternative power conversion concept as it has both
voltage buck and boost capabilities. The developed system
can provide ride through capabilities during voltage sags,
reduces the line harmonics, improves power factor,
increases reliability and extends output voltage range. In
this paper, the proposed Z-source inverter is implemented
to boost the DC voltage generated by PV Panel for feeding
the Induction Motor Drive.
2. Photo Voltaic Panel Modeling
The PV cells are regularly represented by a simplified
equivalent circuit form as shown in the fig.3. The series
resistance RS represents internal resistance to current flow.
The shunt resistance is inversely related to the leakage
current to ground. In ideal RS = 0 and RSh = infinite.
Hence the current derivative can be expressed as:
--(3)
3. SYSTEM DESCRIPTION
The schematic diagram of a ZSI based Solar Power
Generation System fed induction motor drive, where a
unique impedance network is introduced to couple the
inverter main circuit to the power source. The four major
parts: a PV array- Source of DC voltage, Z-Source network
containing two series inductors and two equal diagonally
connected capacitors. For feeding the required DC voltage
to the Z-Source Network, a PV array is used to generate the
DC voltage with proper series and parallel combination of
PV cells. The L1, L2, C1 and C2 are forming the Z- Source
network. The boost function of the generated DC voltage is
achieved by this Z-source network. The ZSI Bridge can
boost the DC capacitors (C1 and C2) voltage to any value
that is the above the average DC value of the PV array. The
desired output voltage is always obtainable regardless of
the line voltage with the help of Z-source bridge.
Comparing the Z-source inverters with the traditional
inverters, a shoot- through state that the upper and lower
switches of any one phase leg are shorten and this is the
added state besides the zero state and active state. This is
the best advantage and feature of the Z-source inverter.
Fig.4 System configuration of ZSI based
Generation System
Fig.3 Equivalent Circuit of PV Cell
The basic equation from the theory of semiconductors that
randomly describes the I-V characteristic of the ideal
photovoltaic cell is:
-- (1)
3. Modeling of Induction Motor drive
The dynamic model of three-phase squirrel cage induction
generator is developed using stationary d-q reference frame.
The involved equations are as:
--(2)
Solar Power
The proposed system is able to feed the three-phase
induction motor drive. The conventional VSI based
Solar System is also capable of supplying power to the IM
drive, but its performance is affected by EMI noise, has
considerable amount of harmonic distortion, high power
loss and low efficiency. Over these problems the
proposed system has the advantages such as both buck and
boost operation is possible less affected by the EMI noise,
low harmonic distortion, low power loss and higher
efficiency.
4. SIMULATION MODEL
The simulation model of the proposed system consists of
PV Panel model, subsystem of Z- source inverter and the
induction motor drive. In this paper, a most recent Z-Source
Inverter (ZSI) feeder with static as well as dynamic load
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(induction motor drive) is proposed and implemented for
remote and rural areas. The ZSI have recently been
proposed as an alternative power conversion concept as it
has both voltage buck and boost capabilities. The
developed system can provide ride through capabilities
during voltage sags, reduces the line harmonics, improves
power factor, increases reliability and extends output
voltage range. Simulation results are given to compare the
behavior of conventional and proposed topology. The
system is modeled using matlab/simulnk and hardware
results also presented. This paper has proposed a Z-source
inverter based induction motor drive with renewable energy
system.
Solar input voltage:
Fig.7 this graph showing the solar input voltage
5. Simulation circuit diagram of a Z-sources inverter
with induction motor:
Hardware kit board:
Fig.5 Simulation circuit diagram of Z-Source
Inverter with induction motor
Fig.8 figure showing the hardware kit circuit
Trigging pulse graph of a inverter:
Diode voltage wave form
Fig.9 diode Voltage graph
Fig.6 Triggering pulses for three-phase inverter
Fig.10 Pulse graph in CRO
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Hardware output:
REFERENCES
(1) L. Sack, B. Piepenbreier and M. von Zimmermann,
"Dimensioning of the Z-source inverter for general purpose
drives with three phase standard motors," in Proc. IEEE
PESC 2008, pp.1808-1813
(2) F. Z. Peng, "Z-source inverter," IEEE Trans. Ind. Appl.,
vol. 39, no. 2, pp. 504-510,Mar./Apr. 2003.
Fig.11 Hardware output voltage
Input 5V voltage
(3) P. C. Loh, D. M. Vilathgamuwa, C. J. Gajanayake, L. T.
Wong, and C. P. Ang, "Z source current-type inverters:
Digital modulation and logic implementation," IEEE Trans.
Power Electron., vol. 22, no. 1, pp. 169-177, Jan. 2007.
(4) R. Antal, N. Muntean, and I. Boldea, "Modified Zsource single-phase inverter for
single-phase PM synchronous motor drives," in Proc.
OPTIM, 2008, pp. 245-250.
Fig.11 Hardware input voltage of 5V
Rotor speed of motor:
(5)Babak Farhangi and Shahrrokh Farhanghi, “Application
of Z-Source Converter in Photovoltaic Grid-Connected
Transformer-less Inverter,” in Proc. of PELINCEC-2005,
Warsaw, Poland, pp. 198-203.
(6)N. Mohan, W.P. Robbins, T.M. Underland
Electronics, John Wiley, 1995
Power
(7) Omar Ellabban, Joeri Van Mierlo and Philippe Lataire,
“Voltage Mode and Current Mode Control for a 30 kW
High-Performance Z-Source Inverter”, IEEE Electrical
Power & Energy Conference (EPEC), 22-23 Oct. 2009,
Montreal, Canada.
Fig.12 this graph showing speed of the motor
6.Conclusion
The renewable energy resource controlled Z-Source
inverter system is simulated using matlab simulink. The
performance with motor load is observed. It is found that
the harmonic distortion by using Z-Source inverter system.
The Z source inverter (ZSI) is one of the effectively reduce
the voltage stress across the capacitors in the impedance
network only and increases the system stability. By making
voltage inverter connected to induction motor the scope of
this paper is simulation of renewable energy resource
controlled Z-Source inverter system. The hardware
implementation is lef as future enhancement.
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