基于多模式控制策略的半桥转换器开关控制方法

Switching Control Method for Half-bridge Converter Based on Multi-mode Control Strategy

提出了一种新型的开关控制方法,通过使用多模式控制策略,而不是修改转换器结构的方式,使用数字控制器在每个负载的子范围内选择控制模式,从而实现在整个负载电流范围内提高半桥转换器的效率。除此之外,当负载电流在满载到空载的整个范围内变化时,可以利用非对称控制、占空比相移控制、脉冲宽度调制(PWM)和突发控制,依次进行模式选择。控制模式之间的三个过渡点是负载电流的特定值,通过比较不同控制模式下的半桥转换器功率损耗,从而确定过渡点的输出功率。数字控制器将负载电流与过渡点进行比较,从而使转换器以最高效率进入控制模式。实验结果验证了所确定的过渡点的准确性以及所提出的控制方法相对于先前方法的效率提升。

A new switch control method was proposed.By using the multi-mode control strategy instead of modifying the converter structure,the digital controller was used to select the control mode in the sub range of each load,so as to improve the efficiency of the half-bridge converter in the whole load current range.In addition,when the load current was changed in the whole range from full load to no load,the mode could be selected by using asymmetric control,duty cycle phase-shift control,pulse width modulation(PWM)and burst control in turn.The three transition points between the control modes were the specific values of the load current,the output power of the transition point was determined by comparing the power loss of the half bridge converter under different control modes.Then,by the digital controller,the load current was compared with the transition point,so that the converter could enter the control mode with the highest efficiency.The experimental results verify the accuracy of the transition point and the efficiency of the proposed control method compared with the previous method.