A method and apparatus for determining the rotor position in a pump driven by a permanent-magnet synchronous motor washing machine

Apparatus and method for determining the rotor stop position of a washing machine motor having an inverter, a permanent-magnet synchronous motor and a motor control electronics. The controller determines the rest position of the motor rotor by measuring induced in the stator field coils of the motor currents. When de-energized and the motor is turning slowly, all stator field coils of the motor are connected to each other from the control by the inverter. The stator field coils can be placed to a common DC rail at the output of the AC / DC converter in the washing machine. In one embodiment, the controller determines the rotor position based on the voltages induced in the stator field coils streams. In another embodiment, the controller determines the rotor position on the basis of the phase angle and angular frequency of the three phase currents after transformation to a stationary frame of reference.