为了实现电容器恒流充电,研究了基于LCL—T谐振变换器的恒流充电技术。首先。运用交流分析法详细阐述了LCL-T谐振变换器在一定条件下实现恒流特性的原理。分析了不同品质因数下开关频率的变化对谐振变换器电流增益和逆变器输出端电压电流相位差的影响;其次,对二极管钳位型LCL—T半桥谐振式电容器充电电源的充电过程和性能进行了分析,并在此基础上设计了一台样机。最后,通过在12s内将2370μF电容器充电至600V的仿真与实验证明了LCL-T半桥谐振式电容器充电电源具有恒流特性,且控制简单。适用于电容器的快速、精确充电。
In order to charge a capacitor in a constant current model, constant-current charging techniques based on the LCL-T resonant converter is investigated in the paper. Firstly, the principle of LCL-T resonant converter having constant characteristics is presented by using AC analytical method. Under different quality factors, switching frequency having influence on the converter current gains and the phase difference between inverter's output voltage and current is analyzed. Then, charging process and performance of the CCPS based on LCL-T resonant converter with clamping diodes are analyzed. Based on the theoretical analysis, a prototype is designed. Finally, the simulation and experiment of charging a 2 370 μF capacitor to the rated voltage 600 V in 12 s are carded out. Simulation and experimental results have proved that the LCL-T resonant converter is shown to be feasible for using as CCPS.