A Sensorless Control Strategy for Long-Cable-Fed PMSM System with LC Sinusoidal Output Filter

This paper investigates a practical sensorless control strategy for permanent magnet synchronous motor (PMSM) drive systems with LC sinusoidal filters in long-cable-fed applications. In such drive systems, the installation of sensors at the motor side becomes challenging due to digital signal delays caused by long signal cables, while the distributed inductance of extended cables introduces phase errors between motor-side currents and LC filter output currents. Furthermore, the introduced LC filter may form an LCL resonant circuit with the motor, significantly compromising system performance. To address these challenges, a full-order sliding mode observer(FSMO) for PMSM control systems with LC filters in long-cable-fed configurations is developed. This method enables online observation of motor-side currents, inverter-side currents, capacitor voltages, and back electromotive force (back-EMF) waveforms for both resonance suppression and position-sensorless control. Simulation and experimentation validate the effectiveness of this method.