| 摘要 |
PURPOSE:To stably perform the regenerative braking even at a high speed time by controlling the current flowing angle of a chopper and a branch thyristor in accordance with the output signal of a current controller and limiting a load side current to a low value when the voltage of a power source is decreased. CONSTITUTION:A controlling circuit 26 receives a differential current signal Vi between the motor current and the set current from a setting circuit 24 and controls the current flow rate of a branch thyristor 10 from alphamin to alphamax with the current flow rate of a chopper 14 as alphamin with the signal Vi being in the range of zero to 50% and controls the current flow rate of the chopper 14 from alphamin to alphamax with the current flowrate of the thyristor 10 as alphamax with the Vi being 50 to 100%. The set current value of the circuit 24 is reduced when the voltage of a power source is dropped lower than the set value. Thus, the regenerative braking can be performed in the wide range and can be controlled stably at a high speed. |
