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.

主权项

1. A system for determining an electrical angle of an electric motor operating at a zero or low speed, wherein the electric motor is characterized by one or more state equations, the system comprising:
the electric motor; an inverter configured to drive the electric motor with a control signal; and a control element configured to—
inject a high frequency voltage demand into the control signal,read a motor current and a motor voltage in a stationary reference frame,transform the motor current and the motor voltage into a diagnostic reference frame,determine a bulk current model for a motor inductance and a motor resistance,update the one or more state equations using a Kalman filter, anddetermine the electrical angle using the updated one or more state equations.