基于计数延时法的移相全桥变换器PWM控制设计

PWM Control Design for Phase-Shifted Full-Bridge Converter Based on Counting Delay Method

移相全桥ZVS变换器在中大功率场合有广泛应用,在数字移相控制系统中,对移相互补驱动输出信号的稳定性,特别是对移相角产生的灵活性具有一定的要求。选用32位ARM内核的单片机,利用其定时器互连关系提出了一种计数延时法,并基于该方法设计了两种ZVS变换器驱动波形产生方案。文中详细介绍了计数延时法产生移相角原理,重点阐述了两种四路移相驱动信号设计步骤,最后通过软件设计实现了移相互补信号的产生,并进行了移相全桥变换器开环和电压闭环实验,实验验证了该计数延时法的可行性,大大简化了全桥变换器移相PWM控制,且为多模块移相全桥变换器的控制奠定基础。

The phase-shifted full-bridge ZVS converter is widely applied in high-power occasions. The stability of phase-shift complementary drive signals and the flexibility of phase-shift angle should meet certain demands in digital control system. A counting delay method has been proposed using the relationship of timers in MCU with 32-bit ARM kernel, based on which two ZVS converter drive waveform generating strategies have been designed. The generating principle of phase-shift angle is described in detail based on counting delay method in this paper. And the emphasis is put upon two design steps of 4-channel complementary drive signals of phase-shift. The generation of phase-shift complementary drive signals is realized using software technology, and the experiments on open loop and voltage closed loop system are performed. The results verify the feasibility of the proposed scheme, which will greatly simplify the ful-bridge converter phase-shifted angle PWM control and lay the foundation of the multi-module phase-shifted fullbridge converters