Comparison of Traditional and Quasi-Z-Source Inverters for Electric Vehicle Applications

Abstract

This paper gives a comparative study of Quasi-Z-Source (QSZ) converter family with the traditional inverters in context to electric vehicle applications. While the traditional inverters have discontinuous input current profile, the QSZ inverters have continuous input current profile resulting in reduced electromagnetic interference (EMI) effect. A special shoot-through concept is elucidated that ensures continuous input current as well as high voltage boost gain. By employing our proposed multi-stage Quasi-Z-Source Inverter (QZSI) network, the shoot-through duty cycle is reduced by 40% to achieve the voltage boost factor same as in single-stage QZSI. Alternatively, it is shown in this paper that the proposed multi-stage converter can achieve higher gain than a single-stage QZSI at a particular duty cycle. The Quasi-Z-Source network is capable of performing the Boost and Buck function in a single stage without going for the external buck-boost converter. The proposed multi-stage QZSI topology along with the single-stage QZSI are analyzed in the steady state and their performances are validated using simulated results obtained in MATLAB/Simulink environment.