| 摘要 |
PURPOSE:To connect a three-phase capacitor to a three-phase AC circuit without using a three-phase transformer and without causing a rush current, by selecting a closed phase of a semiconductor switch so that the switch is closed by a phase of zero of a terminal voltage of each phase semiconductor switch. CONSTITUTION:At the time when a U phase line voltage of a three-phase AC power source 10 is zero, a U shape positive direction thyristor FU and an FV phase negative direction thyristor NV are ignited, capacitors CU, CV of two phases of U phase and V phase are connected to the AC power source 10 without causing a rush current, and at the time when a voltage to a neutral point G of a common connecting point N is equal to a W phase voltage EW of the three-phase AC power source 10, a W phase negative direction thyristor NW is ignited, and a W phase capacitor CW is also connected to the AC power source 10. Thereafter, when a gate signal is applied continuously to all the thyristors, the positive and the negative thyristors of each phase conduct naturally in accordance with the polarity of power supply voltages EU, EV and EW, and the capacitors CU, CV and CW remain connected to the power source. |
