Extended Sliding Mode Disturbance Observer-Based Sensorless Control of IPMSM for Medium and High-Speed Range Considering Railway Application

The sliding mode observer (SMO)-based approach known for its robustness towards parameter variation (external disturbance) has been used for the sensorless motor drive system. Delay compensation is commonly added to overcome the phased delay resulted from the introduction of the low-pass filter for chattering suppression. In this paper, a new extended sliding mode disturbance observer (ESMDO)-based sensorless control of interior permanent magnet synchronous motor for the medium and high-speed range is presented. The effect of parameter variation and coordinate transformation is considered as a lumped disturbance, and ESMDO is designed to compensate for the imminent impact of such scenarios. A Lyapunov stability theory is adopted to guarantee the stability of the proposed ESMDO-based sensorless control method. The ESMDO has an inbuilt low-pass filter and does not introduce a phased delay. A very large load change/reference speed variation may result in system instability or require higher controller gains that lead to system chattering. Hence, a PI-based compensation is incorporated to achieve a smooth and robust sensorless control algorithm considering the d-axis disturbance. Finally, extensive simulation and hardware-in-the-loop (HIL) test using the TMS320F28335 control unit in a real-time environment are conducted to verify the effectiveness of the proposed sensorless control method.