Boost型三电平AC/AC变换器

摘要

针对高输出交流电压的升压场合,研究Boost型三电平AC/AC变换器.相比于Boost型两电平AC/AC变换器,该变换器通过增加开关管数量和引进飞跨电容,构造了中间电平,可使开关管的电压应力降低一半,滤波器重量体积大大减小.其拓扑可以看成是两个输出电压极性相反的Boost型三电平DC/DC变换器组合而成,该变换器输入输出电压同相位,其飞跨电容电压等于输出电压的一半.详细分析其电路工作原理,给出一种新颖的控制策略,可对输出电压和飞跨电容电压同时进行控制;研制一台原理样机,给出了实验波形与测量结果.实验结果证实了理论分析的正确性和控制策略的可行性.%Boost type three-level AC/AC converter was studied,which can be used in step-up occasion with high ac output voltage.Compared with the Boost type two-level AC/AC converter,by increasing the number of switch,introducing a flying capacitor and forming the middle voltage level,the voltage stress of switches in this converter is reduced half,and the volume and weight of its filter is also greatly reduced.Its topology was seen as a union of two Boost type three-level DC/DC converters with opposite output voltages.Its output voltage is in the same phase with the input,and the flying capacitor voltage of the converter is equal to half of the output voltage.The circuit operational principle was analyzed in detail,and a novel control strategy was given which can both control the output voltage and the flying capacitor voltage at the same time.A prototype was designed,and its experimental waveforms and measurement results were given.The experimental results verify correctness of the theoretical analysis and feasibility of the control strategy.