Method and Circuit Arrangement for Determining the Rotor Position of an Ec Motor in the Standstill State

Abstract

The invention relates to a method and a circuit arrangement for determining the position of the rotor of an electronically commutated motor having a plurality of stator phases, whose rotor has magnetic axes having different permeances. Voltage is applied to the stator phases, and the resultant phase currents are monitored for the purpose of determining the rotor position in the standstill state of the motor. For this purpose, first and second rise times of the phase currents are determined until predetermined limit values are reached on the one hand in the unsaturated state, and on the other hand using saturation effects of the rotor core and/or stator core. The assignment of a magnetic axis to a stator phase is determined from the first rise times of the currents in the unsaturated state of the rotor core, and also the polarization of the rotor is determined from the second rise times of the currents in the event of energization with saturation effects. In addition, in a further measurement step after run-up of the motor, an initial energization of the stator, which results from a limit position of the rotor at the sector limit of two stator phases and is unfavorable for a high run-up torque of the motor, can be determined by comparison of the levels of the magnet wheel voltages and corrected by changing the commutation of the stator energization.

Dependencies are inferred from the claim text.