| 摘要 |
PURPOSE:To relieve flicker effectively, by reducing the current limiting value only when the instantaneous value of the voltage of a smoothing capacitor is lowered. CONSTITUTION:The output of an AC power source 1 is supplied to a motor 5 through a rectifying diode 2, a smoothing capacitor 3 and a motor drive circuit 4. The input current of the motor drive circuit 4 is limited in a current limitation circuit 6 in accordance with the voltage drop signal from a voltage drop detection circuit 11, by which the output of an average voltage detection circuit 10 is compared with the partial pressure of the smoothing capacitor 3 and which outputs the voltage drop signal in case the difference is larger than the set point made by a setting circuit. In this way, the flicker can effectively be relieved without worsening accelerating time in starting a motor and without reducing transient torque.
|
