Patent ID: 6448738
Filing Date: 2002-09-10
Classification: B62D,H02P

Abstract:
A method of controlling an electric motor having at least three phase windings, said motor being adapted to produce an output torque in response to currents applied to said windings, the method comprising the steps of:during normal operation, generating a motor torque demand signal indicative of the output torque required from said motor, and applying a first set of currents to said windings of said motor dependent upon the value of said motor torque demand signal, said currents producing an output torque from said motor; and during a test operation in which diagnostics are performed on said motor, generating a motor current demand signal indicative of the total current required in said motor windings and adjusting said currents applied to one or more of said windings such that the algebraic vector sum of said adjusted currents applied to said windings is dependent upon the value of said motor current demand signal and independent of the value of said motor torque demand signal while said adjusted currents produce an output torque from said motor which is substantially equal to said output torque produced by the motor during said normal operation.