Harmonics Suppression for Dual Three-Phase Permanent Magnet motor With Multi-Subspace Model Predictive Control

The conventional virtual voltage vector (VV) based model predictive control for dual three-phase permanent magnet motor is a harmonic subspace open-loop scheme. This paper proposes a remedy method to realize a closed-loop predictive control both in fundamental and harmonic subspace. The harmonic-free VVs are synthesized in the fundamental subspace while the torque-free VVs are synthesized in the harmonic subspace. The optimal VVs are selected in respective subspaces using the predefined cost functions. Then, the duty cycle of the optimal harmonic-free VV is calculated according to the deadbeat principle of dq-axes current. The remaining duty cycle is proportionally allocated to the optimal torque-free VV. In this case, both fundamental and harmonic subspace can be controlled in a closed-loop scheme. Therefore, the harmonic currents and torque ripple can be further suppressed. The simulation and experiments results show that the proposed method can significantly improve the operational performance of the motor.