| 摘要 |
PROBLEM TO BE SOLVED: To stably retain the voltage between the terminals of a capacitor 30 even with respect to rapid variations in the load. SOLUTION: An electronic control unit 40 calculates a neutral point current command, flowing through the neutral point of a motor 22, by dividing power corresponding to output that is requested for the motor 22 by the voltage Vb impressed between the terminals of a DC power supply 32 connected to the neutral point of the motor 22 and a negative pole bus 28 of the inverter circuit 24, and calculates the amount of offset of three-phase AC for driving the motor 22, based on the neutral point current command, namely the amount of offset of the average potential (neutral point potential) of the three-phase AC to the middle potential of the potential in a capacitor 30, with the negative pole bus 28 being set as reference potential. Then, the amount obtained by adding the amount of offset to the three-phase AC is generated by switching of transistors T1-T6 in the inverter circuit 24 and this is applied to the motor 22. |
