Patent ID: 6885970

Claim:
An apparatus for providing a position estimate of a polyphase motor receiving polyphase current from a voltage inverter, the voltage inverter receiving PWM commands from a controller, the apparatus comprising: a current measuring apparatus for measuring at least two polyphase currents; an α-β converter coupled to the current measuring apparatus, the α-β converter operative to convert the polyphase currents into the α-β frame of reference, the α-β converter providing an output of the current in α-β coordinates; the α-β converter further coupled to the controller and receiving the PWM commands therefrom, the α-β converter operative to convert the PWM commands into α-β coordinates and to provide as an output the PWM commands in α-β coordinates; a least square estimator, receiving the current in α-β coordinates and the PWM commands in α-β coordinates, the least square estimator operative to provide an output vector {circumflex over (q)} of estimated parameters, the estimated parameters including estimated inductances of the motor; and a state observer coupled to the least square estimator and receiving the estimated parameters including the estimated inductances of the motor therefrom, the state observer operative to provide an output of an estimate of a mechanical subsystem of the motor that includes a position estimate of the mechanical subsystem of the motor.