| 摘要 |
PROBLEM TO BE SOLVED: To stably control a current even though a current control operation has been saturated by the voltage saturation of a three-phase voltage command by changing a previous value to be added for integrating operation in the PI control arithmetic section to a primary delay having the time constant as same as an integrating time constant with a value after the voltage saturation as a target value. SOLUTION: Since voltage limiter sections 4u, 4v, 4w are sufficient for three phases, window comparators 7u, 7v, 7w for detecting the saturation of respective phases in response to the above are provided. And the logical sum of the results of saturation detection of individual limiter sections 4u, 4v, 4w by the window comparators 7u, 7v, 7w is taken by an OR-gate 8; and if one of the three phases is saturated, PI control lamps 2d, 2q are switched to the primary delay side. By doing this, the current control can be stably performed even though the current control operation is saturated after the occurrence of a fluctuation such as a power voltage fluctuation at the side of the voltage limiters 4u, 4v, 4w. |
