Novel adaptive extended state observer method of active disturbance rejection control for sensorless IPMSMs based on high-frequency square wave injection

Abstract The sensorless control method for built-in interior permanent magnet synchronous motors (IPMSMs) based on high-frequency square-wave (HF) injection is being increasingly applied in electric vehicles due to its compact size and low cost. However, sensorless IPMSMs have weak anti-interference capability and poor dynamic performance, especially at low speeds. A novel adaptive extended state observer (AESO) for the active disturbance rejection control (ADRC) of a sensorless IPMSM with HF square-wave injection is proposed. First, HF square-wave signals are injected into the estimated rotational coordinate system of the IPMSM, and the rotor position estimation error is obtained through signal response extraction and processing. Then, a novel AESO-based ADRC (AESO_ADRC) is designed to replace the traditional PI controller in the speed loop. The characteristics of the AESO are obtained by allocating time-varying eigenvalues based on the differential algebraic spectrum theory (DAST) of the estimation errors of the rotor position, speed, and total disturbances to reduce the disturbance of the state estimation error and the total disturbance. Simulation and experimental results demonstrate that the stabilization time of the AESO_ADRC method is the shortest under sudden changes in load and speed, with nearly zero overshoot. These results indicate that the AESO_ADRC method has good dynamic performance and strong anti-interference capability. Moreover, the method performs well at low speeds of 10 r/min, and the rotor position estimation error is minimum.