基于OTC改进的半桥LLC变换器软启动控制

Improved Half Bridge LLC Converter Soft Start Control Based on OTC

目前传统指数降频的轨迹优化控制方法有效减少了谐振电流峰值,但存在空载或轻载时输出电压超调,软启动时间长等问题。此处基于轨迹优化控制(OTC)提出了一种改进的软启动方法,解释了空载和满载下输出电压稳态调节的频率不同,引入线性补偿解决输出电压超调的问题,分析了LLC谐振变换器在启动过程中的阻抗特性和电流冲击特性,提出平方降频函数实现快速软启动。最后搭建了一台功率为185W用于半导体激光器供电电源的实验样机,验证了所提方法的可行性和有效性。实验结果表明,相比于传统指数降频的轨迹优化控制,所提出的方法在启动过程中实现了输出电压的快速响应和稳态调节。

At present,the traditional exponential frequency reduction trajectory optimization control method effectively reduces the peak resonance current,but there are problems such as output voltage overshoot and long soft start time when unloaded or lightly loaded.An improved soft start method based on optimization trajectory control(OTC)is proposed,explaining the different frequencies of steady-state adjustment of output voltage under no-load and full load,and introducing linear compensation to solve the problem of output voltage overshoot.Analyzed the impedance characteristics and current impulse characteristics of LLC resonant converter during startup,and proposed a square frequency reduction function to achieve fast soft startup.Finally,a prototype with a power of 185 W is built for laser power supply to verify the feasibility and effectiveness of the proposed method.The experimental results show that compared to traditional exponential frequency reduction trajectory optimization control,the proposed method achieves fast response and steady-state regulation of output voltage during the startup process.