Optimized Vector Control strategy for Contrarotating Permanent Magnet Synchronous Motor under serious unbalanced load adopting torque compensation

For a disk-type contra-rotating permanent magnet synchronous motor (CR-PMSM), when the dynamic master-slave control method with sliding mode speed control is employed, the robustness of the rotor in the case of large sudden load variation is poor, speed and torque pulsation of slave rotor under the conditions of heave unbalanced load torque are great. Aiming at these problems, an optimized vector control strategy adopting load torque compensation is proposed in the paper. The strategy realizes the torque current control of dual rotor. Meanwhile, two sliding mode observers are applied to observe load torque of dual rotor, and the observed values are made feedforward compensation to the system. The experimental results show that, by adopting the proposed strategy, the robustness of the rotor is improved when sudden load changes are large, and the dual rotor of CR- PMSM could synchronously track for a given speed with no pulsation in the situation of heavy unbalanced load torque.