Comparison of Z-Source Inverter Fed Induction Motor with Traditional Source Inverter Systems

Abstract: This study presents an impedance-source inverter fed (or Z-source converter) induction motor and its control characteristics compared with other traditional inverters. The impedance source inverter employs a unique impedance network coupled with inverter and rectifier; it overcomes the conceptual barriers and limitations of the traditional voltage-source converter (abbreviated as V-source converter) and current-source converter (abbreviated as I-source converter). By controlling the shoot-through duty cycle, the z-source inverter system provide ride-through capability during voltage sags, reduces line harmonics, improves power factor and extends output voltage range. Analysis and simulation results are presented to demonstrate these features

VOLTAGE PROFILE IMPROVEMENT USING SERIES HYBRID ACTIVE FILTERS INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING AND TECHNOLOGY (IJARET) IJARET © I A E M E

ABSTRACT The increase of nonlinear loads due to the proliferation of electronic equipment causes power quality in the power system to deteriorate. Harmonic current drawn from a supply by the nonlinear load results in the distortion of the supply voltage waveform at the point of common coupling (PCC) due to the source impedance. Both distorted current and voltage may cause end-user equipment to malfunction, conductors to overheat and may reduce the efficiency and life expectancy of the equipment connected at the PCC. An series active filter(SAF), typically consists of a three phase pulse width modulation (PWM) voltage source inverter, when this equipment is connected in series with the ac source impedance it is possible to improve the compensation characteristics of the passive filters in parallel connection. A three-phase series hybrid active filter(SHAF) topology is proposed in this project for improving the voltage profile in a distribution system. It is constituted by a series active filter and a passive filter connected in parallel with the load. The control strategy is based on the instantaneous reactive power theory, so that the voltage waveform injected by the active filter is able to compensate the reactive power and the load voltage harmonics and to balance asymmetrical loads. The proposed algorithm also improves the behavior of the series active filter with the introduction of passive filter. Hysteresis current control PWM method is used for producing switching signals for the switches of voltage source inverter. Simulations have been carried out on the MATLAB-Simulink platform with Non linear load and the results are presented and analysed. The proposed d-q theory effectively produced compensating reference voltage and hysteresis current control PWM method produced the required switching signals to control the switches effectively. The results show that the proposed topology of SHAF improved the voltage quality at the point of common coupling