无极灯电子镇流器频率跟踪控制技术研究

Research on frequency tracking technology of electronic ballasts for electrodeless lamp

基于无极灯电气模型的分析,提出一种适合于无极灯负载特性的控制策略。通过扫频控制寻找谐振频率以产生点灯所需的高压脉冲,正常运行时以半桥逆变器中点电压与谐振电容电压的相位差作为闭环控制变量实现对谐振频率的自动跟踪控制,以获得最大的功率输出和最佳的负载匹配。电路仿真和实验结果验证了所提出的方案是可行的。

Due to the excellent features of high efficiency, high color rendering, no flash and long life, electrodeless lamp becomes a new gas-discharge light source with a good development prospect. Electrodeless lamp has a negative resistance property, so that a reliable electronic ballast assorted is needed for the lamp. Based on the anal- ysis of the electrical model of electrodeless lamp, a novel control strategy suitable for load characteristics of elec- trodeless lamp is presented in the paper. The resonant frequency is searched to get the trigger high voltage by fre- quency sweeping. In order to achieve the maximum output power and best load matching, the phase difference be- tween inverter output voltage and resonant capacitor voltage is adopted as the phase loop control variable to track resonant frequency automatically in normal operation. Finally, the simulation and experiment results have proved the feasibility of the proposed strategy.