| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a circuit device for preventing a large current where a frequency converter cannot allow due to the overvoltage of a power supply circuit network when a power supply voltage extremely fluctuates exceeding an allowable bandwidth. SOLUTION: In a method for matching the DC voltage of the intermediate circuit of a frequency converter to a power supply voltage, DC voltages UZK.ist of the intermediate circuit are varied so that they are larger or at least equal to a rectified peak value UN of the power supply voltage. A power supply voltage obtained from the power supply network 1 is introduced into a rectifier 10, the output signal UN of the rectifier is coupled with the output signal of a reference voltage generator 14, a signal thus generated is introduced to an operational amplifier 12, the output signal of the operational amplifier 12 is introduced into a diode 13, the output signal of the diode is coupled with the output signal of at least a reference voltage generator 14 by an adder 15, a generated signal is introduced to an operational amplifier 16, and a signal thus generated is introduced to the control unit of a semiconductor switch. |
