Impact of Variation in Switching Frequency and Modulation Index on Z-Source Inverter Input Current

Abstract

Many inverter topologies are used for industrial automation, electric vehicle charging stations, and grid integration for renewable energy. Of the different inverter configurations, the Z-Source Inverter (ZSI) receives attention in grid integration of battery and photovoltaic panels. This is due to the unique feature of ZSI, which allows for voltage boost operation in addition to the traditional dc-ac conversion. The power structure of ZSI includes an impedance network interfaced between the input dc source and the 3-leg inverter. Switching frequency and input dc-link voltage have an impact on the performance of the impedance network to start off with, which directly impacts the output characteristics of the inverter as well as the sizing of the components. The impact of the chosen switching frequency on the amount of dc-link current and voltage stress on power electronic switches and load is carefully analyzed in this work. The ideal best-fit values for various parameters, such as switching frequency, modulation index, shoot-through time, and amplitude of dc-link current on the power delivery of ZSI are also supplied with the pertinent mathematical formulas and MATLAB/SIMULINK-based validation. The paper aims to discuss the issues pertaining to the impact of the impedance network values on the energy supplied to and delivered by ZSI in terms of the current drawn at the input as well as the voltage obtained at the output. Through the presented work, an exact idea about the input current required by the ZSI can be determined, which can assist in the selection of the input source and its subsequent grid integration.