用串联连接的电压源PWM变频器抑制变压器冲击电流的方法

A Novel Method of Suppressing the Inrush Current of Transformers Using a Series-connected Voltage-source PWM Converter

提出了抑制变压器冲击电流的新方法。小功率电压源PWM变频器通过匹配的变压器与其他变压器串联。当接通的PWM变频器为阻性时,没有冲击现象发生。单相电路中,电流冲击时充当阻尼电阻的PWM变频器的额定功率为主变压器的14%,而在三相电路中为19%。利用PSCAD/EMTDC技术数字计算机仿真无法确定该方法的有效性和良好的实用性。研制了一台试验样机进行试验,结果证实所提出的方法可以完全避免冲击现象的发生。

This paper proposes a novel method of suppressing the inrush current of transformers, A small-rated voltage-source PWM converter is connected in series to the transformers through a matching transformer. As the connecled PWM converter performs a resistor for the source current, no inrush phenomena occurs. The required-ratings of the PWM converter, which performs the damping resistor for the inrush phenomena, is 14% as compared to that of the main transformers in single-phase circuits. In three-phase circuits, it is 19%. The basic principle of the proposed method is discussed. Digital computer simulation is implemented to confirm the validity and excellent practicability of the proposed method using the PSCAD/EMTDC. A prototype experimental-model is constructed and tested. The experimental results demonstate that the proposed method can perfectly suppress the inrush phenomena.