Fixed Frequency LCC Resonant Converter Modeling and Optimal Design for High-Voltage Capacitor Charging Power Supply in Constant Power Control

Abstract

LCC resonant converter is widely used in high-voltage capacitor charging power supply(CCPS) due to its high efficiency and utilization of parasitic parameters. Since CCPS generally demand a wide voltage variation range, the conventional frequency modulation is difficult to scale up in constant power control. In this paper, a phase-shift(PS) LCC resonant converter in constant power control is proposed. To solve the deviation of the shifted phase of the traditional method in constant power control, an accurate model based on state plane analysis(SPA) is built. On this basis, an optimal design method of PS-LCC for CCPS is proposed, which is helpful to realize the soft switching and reduce the current peak. Finally, a 10kV CCPS prototype is built. And experiment designed by proposed method realizes the constant power charging in PS-LCC for the first time. Experimental results show that the charging speed is increased by 44.3% compared with the traditional constant current charging. Besides, the current stress is reduced by 24.1% and the soft-switching range is extended by 6.9%. There is valuable engineering guidance for realizing high-efficiency and high-speed CCPS by the design method proposed.