Non‐cascade backstepping sliding mode control with three‐order extended state observer for PMSM drive

To simplify the control structure and increase the anti-disturbance performance, a non-cascade control method for a permanent magnet synchronous motor drive system is studied, which regulates the speed and current in one loop. The proposed control scheme is a composite control strategy including speed-current single-loop feedback control and feedforward compensation based on disturbance estimation. A feedback controller based on backstepping sliding mode control is proposed to realise speed-current single-loop. Disturbance estimated by a third-order extended state observer is used in feedforward compensation. Rigorous analysis of stability is conducted to validate the convergence of the control scheme. Simulation and experimental results demonstrate that the proposed control scheme achieves a better speed tracking performance and disturbance rejection property over proportional-integral-derivative and sliding mode control.