| 摘要 |
PURPOSE:To assure a vector control state even if a DC voltage of a PWM inverter is lowered in order to vector-control an induction motor by the inverter having a current control system. CONSTITUTION:Proportional integration control means 6c, 6a proportionally integrate current detected values IOFB, ITFB of exciting axis current command IOS and a torque axis current command ITS, interference term compensators 6d, 6b compensate them to obtain two-phase voltage commands VO, VT of a synchronous rotary coordinate system and a coordinate converter 10 obtains a primary voltage V1 of a motor and its phase phi from the voltages VO, VT. Limiters 6e, 6f limit the voltages VO, VT to limited values of a ratio of a voltage in the case of rating at the normal time, and when the voltages VO, VT tend to exceed the limited values, the previous voltages VO, VT are used as the limited values, and a coordinate conversion output by a primary voltage V1 and previous phase phi is obtained. |
