Self tuning method and apparatus for permanent magnet sensorless control

accelerate target freewheel E A plurality of parameters of a Permanent Magnet Synchronous Motor (PMSM) is determined by a motor controller for differentiating between a plurality of PMSMs. This is achieved by first applying regulated DC motor currents at a commanded fixed rotor angle and measuring a quadrature voltage; parking the PMSM at standstill, Then, after selecting an initial set of controller parameters; applying the quadrature voltage equal to zero and measuring a time constant. Then, accelerating the PMSM with a constant torque up to a preset target speed and measuring a total acceleration time tuntil the preset target speed ωis reached. After regulating a stator current at 0 value, measuring the quadrature voltage and a freewheeling motor speed ωimmediately after applying the 0 stator current; and calculating an electrical constant Kof the PMSM; a load inertia J; and a set of parameters for the controller.