Patent ID: 8928260
Filing Date: 2015-01-06
Classification: B60L,H02P,Y02T

Abstract:
1. A method of adjusting electrical power application in a motor control system using an AC motor driven by an inverter bank that is coupled to a resistive grid during retard operation, the method comprising: calculating a braking factor as a ratio of a nominal power DC voltage vs. a nominal brake DC voltage; calculating a resistance scale factor as a ratio of measured grid resistance vs. a base grid resistance; determining that motor operation is in one of a constant power region or a constant torque region; multiplying a DC link voltage, the braking factor, the resistance scale factor and one of a power scale factor when in a constant power region or a torque scale factor when in a constant torque region to generate an adjusted flux estimate; and setting inverter operation to adjust motor torque based on the adjusted flux estimate, wherein the power scale factor is a function of a measured torque times mechanical frequency vs. a characteristic torque times a corner point mechanical frequency and the torque scale factor is a function of the measured torque vs. the characteristic torque.