具有短路限流能力的大变比DC/DC变换器

提出了一种具有短路自动限流和功率双向流动特性的大变比DC/DC变换器,该变换器适合作为接口电路用在高、低压直流线路之间。该DC/DC变换器以三电平方式工作,通过调节占空比和相移,可以改变其传输功率,并且可以实现功率的双向流动;电路以梯形波电流工作,实现了部分软开关,效率较高;在发生直流短路的情况下,流过开关管的电流峰值与正常工作时相等,实现了自动的短路保护。基于以上特点,设计了一个输入电压为12 kV、输出电压为1 kV、传输功率为100 kW的变换器,通过仿真研究验证了理论分析的正确性。

Large-step-ratio DC/DC Converter with Capability of Short-circuit Current Limiting

A large-step-ratio DC/DC converter with the abilities of automatic current-limiting and bidirectional power flow is proposed. It is suitable to be used as an interface circuit between high voltage direct current (HVDC) and low voltage direct current (LVDC) transmission lines. The DC/DC converter works with three-level voltage. By adjusting its duty ratio and phase shift, the transmission power of the converter can be changed, while the bidirectional power flow can be realized. The circuit operates with a trapezoidal current wave, and realizes partial soft switching with a high efficiency. When a short-circuit fault occurs the DC/DC converter can automatically limit the current, whose peak current value through the switch is same as that in normal operation. Based on these features, a converter is designed and validated by simulation, whose input voltage is 12 kV, output voltage is 1 kV, and transmission power is 100 kW.