Saliency-based position estimation in permanent magnet synchronous motors

摘要

A method and system for the sensorless estimation of the states of the mechanical subsystem of a motor are disclosed. In particular, the method and system split the estimation problem into two sub-problems: the estimation of motor parameters as a function of position, and the determination of the states of the mechanical subsystem of the motor using the estimated parameters via a state observer. Motor current and PWM voltage in a polyphase system is measured or otherwise determined and converted into current and voltage in α-β coordinates. A least square estimator is constructed that uses the voltage and current in α-β coordinates and provides an estimate of the motor parameters, and in particular, the inductances of the motor, which are a function of the rotor position. These estimated inductances are used to drive a state observer whose dynamics have been selected to provide as an output the state of the mechanical subsystem of the motor, and in particular, the position, velocity, and acceleration of this subsystem.