Analysis and Design of a Novel LLC CCPS for Repetitive Pulsed Power Applications

Abstract

This paper presents a novel type of capacitor charging power supply (CCPS) based on LLC resonant DC/DC converter for repetitive pulsed power applications, such as pulsed lasers. Because the load of CCPS is almost capacitive, leading to a quickly varying of output voltage during the charging period, conventional methods are not appropriate and not accurate enough for analyzing the transient characteristics of this proposed LLC CCPS. Thus, an equivalent resistance method based on first harmonics analysis (FHA) method is proposed and parasitic capacitor effect is analyzed too. In order to improve the stability and robustness of the current control system of the proposed LLC CCPS, a PI+LPF type controller combining LUT-based feed-forward is applied. Based on the theories above, a prototype with 200V input and maximum 1kV/2kW output is demonstrated. A peak efficiency of 97.85% and 2A peak average output charging current is achieved and experiments of repetitive pulsed power with 1Hz are carried out. The results prove the superiority of the proposed LLC CCPS. This text explores new topology options for CCPS and aims to improve their performance, the proposed LLC CCPS shows great engineering application value and potential on repetitive pulsed power applications.