考虑寿命和畸变率的极低频功率放大器开关频率优化控制策略

开关功率放大器在民用和军事中都有着广泛的应用,如电动振动试验台、通信系统和声纳探测等重要领域。文中针对应用于极低频电磁波通信的开关功率放大器,提出基于改进粒子群算法的最优开关频率控制策略,通过该方法可以在满足一定输出电压畸变率的同时,降低极低频工况的功率器件热摆幅,延长开关功率放大器的寿命。首先分析开关功率放大器的热应力控制自由度。然后对影响设备寿命长短的重要因素——热摆幅和表征输出效果的指标——谐波畸变率(total harmonic distortion,THD),这2个变量的影响因素进行研究。在此基础上,综合考虑热摆幅和THD,提出基于改进型粒子群优化算法的最优开关频率控制策略。最后,通过仿真和实验对所提控制方法进行验证。

Optimal Control Strategy for Switching Frequency of Very Low Frequency Power Amplifiers Considering Device Lifetime and Distortion Rate

Switching power amplifiers are widely used in civilian and military applications, such as electric vibration test stands, communication systems, and sonar detection. An optimal switching frequency control strategy based on particle swarm optimization(PSO) algorithm was proposed for switching power amplifiers used in extremely low frequency electromagnetic wave communication. While satisfying a certain output voltage distortion rate, it can reduce the thermal swing of power devices under extremely low frequency conditions and extend the life of the switching power amplifier. Firstly, the degree of freedom of thermal stress control of the switching power amplifier was analyzed. Then the important factors that affect the device lifetime —— the thermal swing and the index that characterizes the output accuracy——total harmonic distortion(THD), the influencing factors of these two variables were studied. On this basis, the optimal switching frequency control strategy considering the thermal swing and THD were proposed, which is based on improved particle swarm optimization(PSO) control. Finally, the proposed control method was verified by simulation and experiment.