SENSORLESS SYSTEM AND METHOD FOR DETERMINING MOTOR ANGLE AT ZERO OR LOW SPEEDS

摘要

A system and method for determining electrical angles of electric motors at zero and low speeds without using angle sensors, and a system and method for estimating resistances and temperatures in electric motors, wherein the two systems and methods may be used separately or together. When used together, they substantially simultaneously estimate motor flux linkage, magnet flux, and motor resistance. In particular, the estimated magnet flux is used to derive the electrical angle and to estimate an average rotor temperature, and the estimated motor resistance is used to estimate the average stator temperature. A Kalman filter, which may be a linear Kalman filter or a Luenberger observer, is used to update state equations from which various motor parameters can be derived or estimated. The system and method which works for motors operating at zero and low speeds can be combined with systems and methods that work at high speeds.