低频方波金卤灯电子镇流器及其控制策略研究

RESEARCH ON A LOW-FREQUENCY SQUARE-WAVE ELECTRONIC BALLAST FOR THE METAL HALIDE LAMPS AND ITS CONTROL STRATEGY

该文提出了一种两级低频方波输出的高性能电子镇流器,作为MH灯工作电源。PFC级用于功率因数校正,DC/AC级结合了BUCK DC/DC变换器和全桥DC/AC逆变器的特点, 负载侧输出为低频方波,可有效克服MH灯声共振现象。采用分段控制方法实现镇流器与灯特性的配合,给出了其相应的控制策略。详细分析了它的工作原理和控制方法,给出了主要参数的计算方法。与传统三级低频方波电子镇流器相比,结构简单、所用器件少、可靠性高。电路仿真和实验结果验证了该方案是可行的。

A two-stage low-frequency square-wave electronic ballast with good performance is proposed to operate MH lamps in the paper. The PFC stage is used to obtain high power factor, The DC/DC stage is derived from combining a buck dc/dc converter and a full-bridge dc/ac inverter, it supplies the lamp with low-frequency square-wave current. Due to its low-frequency operation, no acoustic resonance occurs. The discrete control is used to realize the matching of ballasts and lamps. The circuit operation and control method are detailed. The main parameters are calculated. The proposed ballast can save a controller, two active switch, reduce size and possibly increase system reliability over a conventional three-stage low-frequency square-wave electronic ballast. Computer simulation results and experimental measurements are used to verify the theoretical prediction and analytical discussion.