Autonomous position estimation for pm synchronous motors

A method for position estimation in PM synchronous motors is proposed. It is based on the magnetic saliencies and uses the inherent excitation of the standard PWM. Its main attribute is that it can work unlinked from the controller and PWM. This allows implementing it as an autonomous device connected between the inverter and the motor. The estimation method does not require parameters of the motor and is not perturbed by nonlinearities of the inverter. However, it requires the neutral point of the motor to be accessible. Experimental results validating the proposal are presented.