小功率金卤灯电子镇流器的分析及其控制策略

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

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。

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 mieroeontroller for lighting applications is used to promote control performanee.A prototype of 70 W digital HID ballast is built with the whole efficiency of 92%. The proposed circuit is verified with experimental results.