SummaryThis paper proposes a novel speed‐current single‐loop speed regulation controller for permanent magnet synchronous motor (PMSM) based on model‐assisted cascaded extended state observer (ESO) and sliding mode control (SMC), aimed at simplifying the control structure, increasing dynamic performance, and improving antidisturbance performance. Firstly, a cascaded ESO based on model information is designed for the second‐order model of single‐loop control of PMSM. This approach allows for quick and accurate estimation of disturbance without increasing bandwidth, while also reducing the burden of ESO with model‐assisted information. Next, with the estimation disturbance feedforward compensation, the composite controller is constructed based on SMC, which effectively eliminates residual disturbance and reduces chatterings. The stability of the closed‐loop system under the proposed controller is proved strictly. Finally, simulations and experiments are conducted to validate the effectiveness and robustness of the proposed method.