Analysis of Advanced Pulse-Width Modulation Schemes for Z-Source Inverters

Abstract

Modified switching patterns for Z-source inverters (ZSIs) from the traditional inverter schemes have reached the point where further improvements in firing the switches and inserting the shoot-through (simultaneous conduction of same phase leg switches) periods bring crucial benefits. A large variety of control methods, different in concept and performance, have been developed and described. This paper analyses the implementation logics, and comparative merits and demerits of recently-developed carrier-based and space-vector-based modulation techniques of ZSIs. Carrier-based pulse-width modulation (PWM) schemes, such as maximum boost control with third harmonic injection and constant boost control with third harmonic injection, and space vector modulation-based PWM schemes for three-phase ZSIs are investigated. The suitability of these techniques for various applications is also outlined. The objective of this paper is to provide a comprehensive assessment of the above PWM schemes, thereby giving a framework and guidance for the selection of the best technique for each area of application. The analysis is performed with respect to switching stress, boosting capability, voltage gain, total harmonic distortion, ripples in impedance network elements and the range of controllability. All the above control methods are simulated by Matlab/Simulink software and verified by experiments.