零电压开关PWM组合式三电平变换器的优化策略

Optimization Strategies for Zero-voltage-switching PWM Combined Three-level Converter

零电压开关(zero-voltage-switching,ZVS)PWM组合式三电平变换器利用变压器的漏感(或外加谐振电感)和开关管的结电容可以实现开关管的ZVS,同时副边整流电压高频分量小,可以大幅度减小输出滤波器。由于该变换器包含2个变压器,并存在2种工作模式,因此设计相对灵活。为了使变换器获得最佳的工作性能,该文从控制策略和变压器变比两方面对该变换器提出若干优化策略,同时给出具体设计实例,并进行了实验验证。

Zero-Voltage-Switching （ZVS） PWM combined three-level （C-TL） converter realizes ZVS for the switches with the use of the leakage inductances or resonant inductance and the intrinsic capacitors of the switches, and the secondary rectified voltage is close to the output voltage, which can reduce the output filter inductance significantly. The converter includes two transformers and has two operation modes, which brings on the flexibility of the parameters design. This paper proposes some optimization strategies for C-TL converter based on the control strategies and turns-ratios to achieve a better performance. A prototype converter has been tested for the verification of the theoretical analysis.