A Predictive Encoderless Control Technique for PMSMs: Enabling Loaded Standstill Operation

High-frequency signal injection is an effective approach to enhance encoderless operation at low speeds. However, since it relies on a modulation module, it cannot be integrated with direct model predictive control (MPC), which offers better dynamic performance. Therefore, existing predictive encoderless control methods lack stable operating capability in the low-speed range. In this work, we propose a multivector predictive encoderless control technique with high-frequency injection, achieving low-speed range operation requiring no encoder. Moreover, to eliminate the signal distortion caused by coherent demodulation, a time-domain demodulator based on the stationary reference frame is introduced. The effectiveness of this approach has been validated by experimental results.