| 摘要 |
PURPOSE:To reduce the variation in the voltage of a chopper control inverter by abruptly lowering the output of a controller to the prescribed level when the output of a chopper exceeds the limit voltage, thereby enabling to lower the rated voltage of an element which forms a chopper control inverter. CONSTITUTION:When the output of a chopper 2 exceeds the prescribed limiting voltage, the output of an operational amplifier 17 is inverted, and saturated. The absolute value of the saturated negative polarity voltage becomes larger than the negative polarity voltage as the output of a controller 13, and the output voltage of the controller 13 is lowered to the level of the saturated output voltage of the amplifier 17. The signal to a phase shifter 14 is limited rapidly without almost time delay of the operation of a voltage limiter 16 which includes the amplifier 17 to suppress the rise of the output voltage of the chopper 2. |
