基于负载电流的自适应脉冲序列控制移相全桥变换器

Adaptive pulse train control for phase shift full bridge converters based on load current

针对脉冲序列控制移相全桥DC-DC变换器输出电压纹波大、负载范围小的问题,提出了一种基于负载电流的自适应脉冲序列控制技术。在每一个开关周期,通过采样负载电流产生两组预设电流值,并由电压外环选择预设电流值,再由电感电流内环控制有效占空比,实现对移相全桥DC-DC变换器的控制。分析了自适应脉冲序列控制移相全桥变换器的工作过程和控制原理,研究了不同负载时自适应脉冲序列控制移相全桥变换器的参数设计和输出电压特性。与传统脉冲序列控制和峰值电流控制相比,自适应脉冲序列控制优化了变换器的输出电压纹波,增大了负载范围,极大地提高了瞬态响应速度。最后,通过搭建额定输出电压电流为28 V/4 A的实验样机,验证所提出控制策略的可行性。

To address the large output voltage ripple and the narrow load operation range problem of pulse train(PT)controlled phase shift full bridge DC-DC converter,an adaptive pulse train(APT)based on the load current was proposed.During each switch cycle,in the proposed control method the load current was sampled and two sets of current thresholds were generated.The outer voltage loop decides which cur-rent thresholds is used and the current inner loop generates the effective duty cycle to implement the phase-shift control.The principle and process of APT control technique were introduced.The output volt-age characteristics and the parameter design of APT control converter at different loads were studied.On the premise of enjoying much lower output voltage ripple,APT controlled phase shift full bridge DC-DC converter has wide load operation range,and improve transient performance than the traditional PT and peak current controlled converter.Finally,a prototype with rated output voltage and output current of 28 V/4 A was built to verify the feasibility of the proposed control strategy.