| 摘要 |
PURPOSE:To enable performing a motor stable smooth operation by suppressing and controlling an inverter output voltage lower than a proportional value for a frequency at a regenerative braking time. CONSTITUTION:A voltage compensating circuit 14 receives a DC voltage VDC output from a rectifier 2 through a varibale resistor and an output of a slant signal generating circuit 7, discriminates a polarity of the DC voltage VDC and in case of negative i.e. when a motor 5 is under a regenerative braking start, the above mentioned megative voltage is applied to a voltage controlling circuit 8 according to an output value of the slant signal generating circuit 7 and performs a compensating action so as an inverter output voltage V and a frequency f to be a curve C shown in the drawing. |
