Performance Analysis of Z-Source Inverter Fed Induction Motor Drive With Variable Load Torque

Abstract

Z-Source inverter is a one stage power converter and used for buck or boost the voltage without using additional dc-dc converter bridge. It uses a special network which connects main circuit and power supply, and hence providing special features which will not be achieved by using traditional current and voltage-source inverters, where capacitor and inductor arranged together in X-fashion. It provides voltage buck or boost properties and reduces voltage stress across capacitors and thereby increases efficiency of circuit. This topology finds many applications in renewable energy source where voltage varying from time to time. Actual speed of an induction motor can be sensed by connecting speed sensor which is compared with reference speed. During voltage changes and normal operating conditions it will provide effective speed control of drive. This paper presents performance characteristics of induction motor drives fed with ZSI. To make easy understanding of speed control of ZSI fed induction motor drive, V/F control with simple boost control PWM technique is used. A PI controller is used in this circuit which helps in running motor at reference speed. Simulation is done in MATLAB/ Simulink and Simulation results of induction motor drive with z-source inverter compared with traditional VSI fed induction motor drive which gives good performance at variable speed and torque characteristics.