Performance evaluation of Z-source inverter and voltage source inverter for renewable energy applications

Abstract

There have been a technological advancement in the traditional current source inverter (CSI) and voltage source inverter (VSI), by reducing the number of power processing stages as well as reducing the number of components used in the system; impedance network does it all, whereas in case of traditional inverter complex circuitries are required to buck and boost the input DC voltage. Some modifications have been done in traditional pulse width modulation (PWM) pulses to achieve shoot-through pulses, which is only suitable for the Z-source inverter, (in VSI and CSI, it may destroy the inverter bridge due to short-circuiting) for boosting or bucking of input DC voltage. Impedance network consists of passive elements which help in converting direct current (DC) to alternating current in a single stage. This paper compares conventional as well as the up-coming Z-source inverter and discusses operating modes of the Z-source inverter, mathematical equations, and different pulse width modulation techniques. ZSI is the most suitable configuration for solar photovoltaic applications where sunlight is abundantly available. Simulink modelling is done using software MATLAB. A laboratory prototype is prepared and the results are verified. Spartan-3E is used for giving PWM pulses for voltage source and Z-source inverter.