| 摘要 |
PURPOSE:To control a harmonic current by causing a specific width pulse current to flow through both ends of the current applied for a given period of the secondary current of a motor according to the speed of said motor. CONSTITUTION:The secondary circuit of a motor 1 has a subchopper circuit 20 in parallel with a three-phase full-wave rectifier 3. The secondary phase voltage of said motor 1 is detected by a voltage detector 21 and a triangular wave synchronized with said secondary phase voltage is generated from a triangular wave generator 22. A pulse generator circuit 24 generates a pulse signal on the basis of respective output signals from the voltage detector 21, a triangular wave generator 22 and a speed detector 23 and controls a subchopper circuit 25 and a chopper circuit 4 via gate circuits 25, 27. Said subchopper circuit 25 causes a specific width pulse current to flow through both ends of the current applied for a given period of the secondary current of said motor 1 according to the speed of the motor. The secondary current of the motor 1 is a synthetic current of a pulse current from the chopper circuit 4 with that from the subchopper circuit 20. |
