| 摘要 |
PROBLEM TO BE SOLVED: To obtain a small size unit which provides less magnetic noise and torque variation with a simplified structure. SOLUTION: A control flag group generating means 7 for controlling transition of a voltage vector is provided in the front stage of a voltage vector generating means 623 for outputting a voltage vector to a PWM inverter 3 on the basis of deviation between the primary magnetic flux command value and primary magnetic flux vector, deviation between a torque command value and a momentary torque value and a phase angle of the primary magnetic flux vector. The switching frequency of the PWM inverter 3 is controlled to the predetermined frequency without relation of each arithmetic operation period of the primary magnetic flux vector and momentary torque value. Since the switching frequency of the PWM inverter 3 can be controlled, heat generation of the PWM inverter 3 can be controlled by limiting the upper limit of the switching frequency and a small size cooling apparatus can be realized. Magnetic noise and torque variation can be controlled by limiting the lower limit of the switching frequency. |
