Patent ID: 6377017
Filing Date: 2002-04-23
Classification: B60L,H02P,Y02T

Abstract:
A control device for an alternating current motor, comprising:a target current generating unit which generates a current order value, based on a torque order, as a d-axis target current and a q-axis target current on dq coordinates which are of a rotating rectangular coordinate system; a current detection device which detects an alternating current supplied to each phase of a polyphase alternating current motor; a coordinate transforming unit which transforms said alternating current detected by said current detection device into a d-axis current and a q-axis current on said dq coordinates; and a vector control unit which carries out a current feedback control so that said d-axis current follows up said d-axis target current and said q-axis current follows up said q-axis target current, wherein said vector control unit further comprises: an operation switching unit which, depending on whether a back electromotive voltage of said alternating current motor is greater than or equal to a predetermined value, calculates one of a d-axis deviation and a q-axis deviation from the deviation between said d-axis target current and said d-axis current and the other one of the d-axis deviation and the q-axis deviation from the deviation between said q-axis target current and said q-axis current; and an integration controlling unit which outputs a d-axis integration voltage order value proportional to an integral value of said d-axis deviation and a q-axis integration voltage order value proportional to an integral value of said q-axis deviation, wherein an alternating current supplied to each phase of said alternating current motor is controlled based on an output of said integration controlling unit.