Composite Sliding Mode Control for TPMM Velocity Drive via a Disturbance Observer

Tubular permanent magnet motor (TPMM) can offer great thrust force density and high efficiency. To enhance its robustness against disturbances and solve the contradiction between response time and overshoot, a novel sliding mode control strategy based on disturbance observer (DOB-SMC) was proposed for a TPMM velocity drive system. The novelty of the proposed velocity control strategy lies in the incorporation of the mismatch disturbance observer in the sliding surface and the sliding mode control (SMC) law, and the introduction of internal model control (IMC) into the SMC law. The velocity control system is transformed to a first-order inertia model by IMC, thus the dynamic response performance is improved. The mismatched disturbances are estimated and the equivalent control voltage is employed, and then the effect of mismatched and matched disturbances can be restrained with little chattering. The simulated and experimental results are presented as validation for the proposed strategy.