Comparison of two-individual current control and vector space decomposition control for dual three-phase PMSM

The two-individual current control loops and vector space decomposition (VSD) control for a dual 3-phase PMSM are compared and investigated in this paper. It is found that the VSD control has more flexibility on controlling the fundamental current in αβ sub-plane and the fifth, seventh current harmonics in z1Z2 sub-plane with different PI gains, while the two-individual current control is equivalent to the VSD control with same PI gains in αβ and z1Z2 sub-planes. It is also found that there is potential instability for the two-individual current control, which is due to the mutual coupling between the two sets of 3-phase windings. That being the case, this paper investigates the mutual coupling conditions under which the two-individual current control stable operation can be guaranteed. Under the stable operation, the two-individual current control loops could have the same dynamic performance as the VSD control. Experimental results on a prototype dual 3-phase PMSM are presented to validate the theoretical analysis.