Simulation of Z-Source Inverter Fed Three Phase Induction Motor Drive

IJSRD - International Journal for Scientific Research & Development| Vol. 3, Issue 10, 2015 | ISSN (online): 2321-0613

Simulation of Z-Source Inverter Fed Three Phase Induction Motor Drive Suneel kirar1 C.S. Sharma2 PG Scholar 2Associate Professor 1,2 Department of Electrical Engineering 1,2 Samrat Ashok Technological Institute Vidisha, (M.P.) India 1

Abstract— This paper presents performance characteristics of Z-source inverter (ZSI) fed Induction Motor (IM) drives.

Z-Source inverter is a single stage converter which performs both buck-boost energy conversions using the LC impedance network. This reduces the voltage range of the capacitors used and also the cost of the proposed topology which is in turn used to control the speed of an induction motor which is used in many valuable industrial applications. The Z Source inverter is a combined inverter with an additional buck-boost feature and the proposed topology increases the efficiency of the circuit by reducing the voltage stress across the capacitors. The z-source inverter is very advantageous over traditional inverters and we can be employed all ac and dc power conversion applications. Z-source inverter can boost dc input voltage with no requirement of dc to dc boost converter or step up transformer hence overcoming output voltage limitation of voltage source inverter as well as lower cost. A comparison among conventional PWM inverter dc to dc boost PWM inverter and control circuit cost which are the main a power electronics system.

Key words: Converter, current-source inverter, inverter, voltage-source inverter, Z-Source inverter, Three phase induction motor.

I. INTRODUCTION Z-source inverter can boost dc input voltage with no requirement of dc-dc boost converter or step up transformer, hence overcoming output voltage limitation of traditional voltage source inverter as well as lower its cost. The Zsource inverter advantageously utilizes the shoot-through states to boost the dc bus voltage by gating on both the upper and lower switches of a phase leg. Therefore, the Zsource inverter can buck and boost voltage to a desired output voltage that is greater than the available dc bus voltage. In addition, the reliability of the inverter is greatly improved because the shoot-through can no longer destroy the circuit.

There are two traditional converters: voltage-source (or voltage-fed) and current-source (or current-fed) converters (or inverters depending on power flow directions). The gain of the inverter can be controlled by using pulse width modulation. Z-Source Inverter for induction motor drives. Z-Source Inverter can be applied to the entire spectrum of power conversion. It is used as BoostBuck conversion where a capacitor and inductor are used. In this thesis, the Z-Source Inverter is considered in place of Voltage Source Inverter and Current Source Inverter.

II. Z SOURCE INVERTER A unique impedance network is used in the zsource inverter that consists of two identical inductors L1 and L2 alongwith two identical capacitors C1 and C2 that couples the power supply circuit to the inverter circuit. The

shoot through period i.e., the time period when two switches of the same leg are gated allows the voltage to be boosted to the required value when the input dc voltage is not upto the required level. Else otherwise, the shoot through state is not used thus enabling the ZSI to operate as both a buck-boost inverter unlike the traditional voltage source and the current source inverters.

Fig. 1: Equivalent circuit of z-source inverter The above figure shows the presence of the z source impedance network preceding the inverter main circuit. The diode is used to prevent the reverse flow of current in the circuit. Fig 2a&2b represent the equivalent circuit of the Z source network in shoot through and non shoot through states respectively. The energy is stored in the inductors in the shoot through state when both the switches on the same leg of the inverter are gated. This energy is then transferred in addition to the supply voltage to the load side when normal gating of the inverter switches occur.

Fig. 2: Equivalent circuit of Z source inverter in (a).shoot through state and (b) non shoot through state.

III. INDUCTION MOTOR Induction motor has been used in the mainly in application requiring a constant speed because conventional method of their speed control has either been expensive or highly inefficient. Variable speed applications have been dominated by dc drive. Availability of thyristors, power transistors, IGBT and GTO has allowed the development of variable speed 1induction motor drive. The main drawback of dc motor is the presence of commutated and brushes

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Simulation of Z-Source Inverter Fed Three Phase Induction Motor Drive (IJSRD/Vol. 3/Issue 10/2015/064)

Three phase induction motors are the most widely used in various industrial applications because of the following properties – 1) Self starting property

2) Elimination of a starting device 3) Robust construction 4) Higher power factor and good speed regulation.

IV. CIRCUIT AND SIMULATION

Fig: 3- Simulation result of rectification.

Simulation is performed using MATLAB/SIMULINK injection method is used PWM generation and simulation. software. Simulink liabrary files include inbuilt models of The complete simulation diagram is shown in the figure 5.2. many electrical and electronic components and devices such The component values of z-source inverter depend on as diodes, MOSFETS, capacitors, inductors, motors, power switching frequency only. For this circuit L1 = L2 = 8.5mH supplies. The circuit components are connected as per and C1 = C2 = 250uF. The purpose of the system is to design without error, parameters of all components are produce 230V line to line voltage. For PWM generation the configuration as per requirement and simulation is perform. carrier frequency is set to 10 kHz and modulation reference Maximum constant boost control with third harmonic signal frequency is set to 50Hz.

Fig. 4: Simulation of z-source inverter fed three phase induction motor

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Simulation of Z-Source Inverter Fed Three Phase Induction Motor Drive (IJSRD/Vol. 3/Issue 10/2015/064)

Fig. 5: Input Waveform of Applied Ac Voltage.

Fig. 6: Output wave form of DC voltage.

Fig. 7: Waveform of stator current.

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Simulation of Z-Source Inverter Fed Three Phase Induction Motor Drive (IJSRD/Vol. 3/Issue 10/2015/064)

Fig. 8: Load voltage waveform

Fig. 9: Rotor speed in rpm of induction motor.

Drives”, Journal of Power Electronics, Vol. 12, No. 2, V. CONCLUSION May/June 2010.

[4] K.Niraimathy, S.Krithiga, “A New Adjustable-Speed This paper has proposed a Z – source inverter based Drives (ASD) System Based On High-Performance Zinduction motor drive. This drive system has the advantages Source Inverter”, 978-1-61284-379- 7/11/2011 IEEE, of both PMBDCM and Z-source inverter. The system 2011 1st International Conference on Electrical Energy configuration, operation principle and control method have Systems. been analyzed in detail. And based on the equivalent [5] Muhammad H. Rashid, “Power Electronics”, Second circuits, the mathematical model has been established by Edition, Pearson Education. state-space averaging method. Simulation results have [6] Miaosen Shen, Jin Wang, Alan Joseph, Fang Zheng validated the preferred features as well as the possibility of Peng, Leon M. Tolbert, and Donald J. adams, “Constant the proposed drive system. Additionally, the shortcoming of Boost Control of the Z-Source Inverter to Minimize switching loss has been discussed, and a possible Current Ripple and Voltage Stress”, IEEE Transactions improvement method has been presented. A PWM control on industry application vol. 42, no. 3, May/June 2006. method was carried out in this paper for z-source Inverter [7] Omar Ellabban, Joeri Van Mierlo and Philippe Lataire, fed induction motor drive. The output voltage obtained from “Comparison between Different PWM Control Methods ZSI is not limited and can be boosted beyond the limit for Different Z-Source Inverter Topologies” IEEE imposed by conventional VSI Transactions on industry application, May/June 2010.

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Analysis of a Reduced Switch Z-Source Inverter fed IM

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