Research on Rotor Position Estimation Method for Fault‐Tolerant Permanent Magnet Rim‐Driven Motor Based on Adaptive Dual‐Frequency High‐Frequency Square‐Wave Voltage Injection

To mitigate the issues of excessive harmonic noise and low rotor position estimation accuracy in the sensorless control of fault‐tolerant permanent magnet rim‐driven motor (FTPM‐RDM) using the conventional high‐frequency (HF) voltage injection method, a rotor position estimation algorithm based on adaptive dual‐frequency HF square‐wave voltage injection is proposed. The proposed method adaptively alternates between square‐wave voltages of different frequencies and dynamically adjusts the switching probability. It effectively prevents the spectral concentration of the response current that would otherwise result from injecting the same‐frequency square‐wave voltage over multiple consecutive cycles, thereby reducing harmonic noise and improving position estimation accuracy. Furthermore, in the event of a single‐phase open‐circuit fault, the proposed method, combined with a fault‐tolerant control strategy, can still accurately estimate the rotor position. Simulation and experimental results demonstrate that the proposed method achieves a lower power spectra density (PSD) peak and smaller rotor position estimation error, verifying its effectiveness and superiority.