VECTOR CONTROLLER FOR INDUCTION MOTOR

PURPOSE:To make it possible to quickly respond at the time of start of operation and also reduce power consumption at the time of stop and arithmetic burden to a microcomputer to relatively small levels. CONSTITUTION:In the operation from stop to speed control start state, an operation command equipment 13 outputs an exciting current control signal 13b to an exciting current command generating equipment 10 so as to output an exciting component current command signal during stop by considering the power consumption during stop and start frequency. If the exciting component current command signal during stop is small, then power consumption during stop decreases, but an exciting component current ild requires a time for reaching the exciting current command value ild* during operation, and control start of a speed control equipment 8 is delayed. On the contrary, if the exciting component current command signal during stop is large, then the control start of the speed control equipment 8 is quickened but power consumption increases.