| 摘要 |
In the present invention, in a current control unit AVR, PI control is carried out and voltage command values Vd_cmd, Vq_cmd are calculated, on the basis of the deviation between a d-axis current command value Id_cmd and a d-axis current detection value Id_det and the deviation between a q-axis current command value Iq_cmd and a q-axis current detection value Iq_det. In addition, a neutral point potential control unit NPC calculates a neutral point potential compensation amount V_cmp for compensating the voltage deviation of smoothing capacitors which are connected in series. In a limiting means 4, the neutral point potential compensation amount V_cmp is limited from when operation begins until a preset amount of time has elapsed. In an adder 3, the limited neutral point potential compensation amount V_cmp and the voltage command value Vd_cmd are added, and a compensation voltage command value V_cmd' is calculated. On the basis of the compensation voltage command value V_cmd', PWM control is carried out by a PWM control unit PWM. Due to this configuration, in a three-phase neutral point clamped power conversion device in which PWM control is carried out, interference between current control and neutral point potential control is suppressed. |
