철도차량용 반도체 변압기의 절연구간 통과 방법

초록

This paper proposes an operation method for an SST (Solid-State Transformer) for passing an AC to AC neu tral section. An SST for a railway vehicle is composed of an AC/DC converter and DC/DC converter. AC/DC converter regulates the 25 kV high AC voltage to over 40 kV high DC voltage and DC/DC converter converts the high DC voltage to 1500 V DC voltage. MCB (Main Circuit Breaker) reaches OFF before passing the neutral section and the high DC volt age decreases gradually because SST does not engage in any control. If MCB reaches ON in the condition in which the high DC voltage is smaller than the high AC voltage after passing the neutral section, the power semiconductors are dam aged due to the large inrush current. Therefore, the proposed method uses DC/DC converter to charge the high voltage capacitor using the stored energy at the low voltage capacitor until the voltage of the high voltage capacitor is larger than the high AC voltage. The proposed charging method with DC/DC converter can charge fast and suppress inrush current. This paper presents the operation method of the SST for passing the neutral section; the performance is proved using sim ulation

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