Initial position detection of electric motor

Abstract

A method for initial position detection of an electric motor includes the following steps: determining a delta wiring voltage for each of three pairs of stator windings by sequentially energizing and de-energizing each of the three pairs of stator windings; measuring the delta wiring voltage by an unenergized stator winding connected to a center tap of a respective each pair; determining the minimum triangular wiring voltage according to the absolute value of the minimum value of the three triangular wiring voltages, wherein the minimum delta wiring voltage is associated with remaining stator windings not included in the respective pair; and comparing two delta wiring voltages that are not associated with the minimum delta wiring voltage to determine a proximity of the remaining stator windings to one of a D-axis of a rotor of the electric motor and a Q-axis of the rotor.

Description

technical field [0001] The present disclosure relates generally to electric motors, and more specifically, to determining rotor position and polarity prior to starting the electric motor. Background technique [0002] Permanent magnet synchronous motors (PMSM) typically undergo a rotor alignment process prior to starting. Without rotor alignment, the PMSM could temporarily reverse direction or experience mechanical vibration during the start of operation, which is not acceptable in many actuator or electric vehicle applications. Traditionally, sensors including Hall devices, optical encoders, and inductive encoders have been used to detect rotor position. Using sensors to detect rotor position increases system complexity and reduces safety due to the possibility of additional component failures. [0003] Recent sensorless systems for detecting rotor position rely on time-consuming current measurements, accurate sampling of the stator inductor voltage, and / or sampling of th...

AI Technical Summary

Problems solved by technology

Each of these methods reduces the reliability of rotor position detection, increases cost, complexity, and in some cases increases the start-up time of the motor

Additionally, conventional techniques for determining rotor position result in less accurate estimates of rotor position

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