| 摘要 |
PURPOSE:To effect positive starting by a method wherein an inverter is controlled to change an armature current from the upper limit of an objective value to the lower limit of the same when a brushless DC synchronous motor, in which the position of a rotor is detected by the terminal voltage of the coil of an armature, is started. CONSTITUTION:VVVF, obtained by rectifying an AC power source 1 by a rectifier 2 and inverted by an inverter 4, is supplied to the coil 5-1 of an armature to drive a rotor 5-2 consisting of permanent magnets. An armature current is detected by the voltage drop due to a current IL, flowing through a low resistor R1 inserted into the return passage of the inverter 4, while the detected value is inputted into a current control circuit 8. The position of the rotor 5-2 is detected by a detector 6 based on voltages VA-VC generated in the coil 5-1. A low frequency synchronous starting signal 95 is produced by the program of a ROM accommodated in the microcomputer 7. The microcomputer 7 inputs the desired value 11 of current into the current control circuit 8 and outputs a chopper signal 10. A base drive circuit 9 changes the armature current of the motor from the upper limit to the lower limit of a target value by the signal 9S and the chopper signal 10. According to this method, the motor may be started and stopped smoothly. |
