小功率金卤灯电子镇流器的分析及其控制策略

提出了一种基于半桥双Buck结构的两级低频方波金卤灯电子镇流器.前级为功率因数校正电路,后级的半桥双Buck逆变电路为金卤灯提供150Hz的低频方波电流,有效避免了声共振的发生.在稳态过程中通过控制Buck电路开关管的导通时间来控制灯端功率,并提出过渡过程的控制策略;AVR照明专用单片机的运用,保证了控制策略的实现.通过70W金卤灯电子镇流器的样机实验,验证了电路及控制策略的可行性.

Analysis on a novel Electronic Ballast for Low-wattage MH Lamp and its Control Strategy

This paper presents a low-cost low-frequency square-wave digital electronic ballast for metal halide(MH) lamp.A highly efficient and reliable topology-dual Buck half-bridge inverter (DBI) are adopted to supply the lamp with low-frequency square-wave positive and negative current to avoid acoustic resonance.The constant bus voltage is provided by the front end PFC stage.Power control is realized by controlling the turn-on time of Buck switching device during transient and steady states,a control strategy for transient process is discussed.The AVR special microcontroller for lighting applications is used to promote control performance.A prototype of 70 W digital HID ballast is built with the whole efficiency of 92%.The proposed circuit is verified with experimental results.