Analysis, design, and implementation of closed loop control of electrolytic capacitor-less six-pulse DC link inverter

Abstract

Three-phase inverters in UPS, electric vehicles or hybrid electric vehicles use dc link electrolytic capacitor to establish an intermediate dc link, which has reliability issues and is one prominent cause of inverter failure. Large volume of electrolytic capacitor increases size and cost of the system. Recent research on electrolytic capacitorless inverter using six pulse modulation (SPM) technique along with high frequency power conversion has tried to address this issue. In this paper, closed loop operation of an electrolytic capacitorless inverter is presented. A 1kW laboratory prototype has been built and tested under different loading conditions to verify the proposed analysis and implemented control system.