A Comparative Study of Different Capacitor Voltage Control Design Strategies for Z-Source Inverter

Abstract

The Z-source inverter (ZSI) is a prominent single-stage power conversion topology compared to traditional voltage source inverter (VSI)/ current source inverter (CSI). It adds the additional buck boost capability to input voltage with improved reliability. However, the non-minimum phase (NMP) behavior is the major disadvantage of ZSI due to the existence of the right half plane (RHP) zero in the converter transfer functions. The existences of RHP zero destabilize the wideband feedback loops, which imply high gain instability and introduce the constraints on controller design. This paper presents different types of controllers and its design to maintain the required capacitor voltage with better transient response for non-minimum phase ZSI. Different tuning algorithms have been considered for both proportional integral (PI), and integral proportional (IP) control schemes. Also, the unified control algorithm has been implemented with both simple boost pulse width modulation (SBPWM) and a modified space vector pulse width modulation (MSVPWM) schemes to obtain the required capacitor voltage. The converter performance is comprehensively analyzed for different controllers and observations are tabulated. The complete analysis has been carried out using the MATLAB/Simulink environment for the proposed models. 2019, 2019 IETE.