| 摘要 |
PROBLEM TO BE SOLVED: To enlarge the operation range of a one-cylinder rotating system of compressor without raising the motor cost. SOLUTION: As a drive method for this motor, the other end each of resistors 14u, 14v, and 14w whose one end each is connected to the output terminal of each phase of an inverter 12 is connected with one another to get the first neutral point voltage, and also one end each of the stator windings 13u, 13v, and 13w of each phase of a brushless DC motor 13 is connected with one another to get the second neutral point voltage. Here, based on the difference between the first neutral point voltage and the second neutral point voltage, the position of the magnetic pole of the rotor 13e of the brushless DC motor 13 is detected, and the voltage amplitude is changed by the inverter 12. Hereby, in the case that the velocity of the brushless DC motor 12 is controlled, the ripple voltage put forward of the phase of the load torque, synchronizing with the pulsation of the load torque, is superposed on the average value voltage command. |
