Patent ID: 6304052
Filing Date: 2001-10-16
Classification: H02P

Abstract:
A control system for an interior permanent magnet motor having a rotor defining a plurality of rotor poles, a stator defining a plurality of stator poles and at least one phase winding associated with at least one stator pole, said control system comprising:a first regulator for receiving a torque command signal and a motor torque signal and for providing a stator current command signal responsive to the difference between the motor torque and the torque command signal, said stator current command signal divided into a direct-axis current command signal aligned with a direct-axis of the rotor and a quadrature-axis current command signal aligned with a quadrature-axis of the rotor;a second regulator for receiving a modified quadrature-axis current command signal in response to summing the quadrature-axis current command signal with a motor quadrature-axis current command signal indicative of the actual quadrature-axis current of the motor and for providing a regulated quadrature-axis current signal responsive to the difference between the modified quadrature-axis current command signal and the motor quadrature-axis current signal;a third regulator for receiving a modified direct-axis current command signal in response to summing the direct-axis current command signal with a motor direct-axis current signal indicative of an actual direct-axis current of the motor and for providing a regulated direct-axis current signal responsive to the difference between the modified direct-axis current command signal and the motor direct-axis current signal;a limiter for preventing the modified direct-axis current command signal from exceeding a maximum stator current and allowing any current in excess of the maximum stator current to be added to the modified quadrature-axis current command signal;a fourth regulator for receiving the regulated quadrature-axis current signal and providing a first field weakening signal that increases the direct-axis current command signal when a quadrature-axis voltage approaches a desired maximum voltage;a fifth regulator for receiving the regulated direct-axis current signal and for providing a second field weakening signal that decreases the quadrature-axis current command signal when a direct-axis voltage approaches a desired maximum voltage; andan inverter circuit coupled to the motor for applying a modulated current signal that is a function of the regulated direct-axis current signal and the regulated quadrature-axis current signal to the stator windings of the motor in a preselected sequence to rotate the rotor.