Decoupled Vector Control Scheme for Dual Three-Phase Permanent Magnet Synchronous Machines

Dual three-phase electric machines have many advantages compared with conventional three-phase machines. However, the properties of such machines present challenges for current control that make it difficult to produce sufficient performance for the electric drive. This paper introduces an improved vector control scheme for dual three-phase permanent magnet synchronous machines. The study includes detailed solutions for key parts of the control such as reference frame transformations, decoupling of the current control loops, and modulation. The performance of the suggested control scheme is evaluated using finite-element analyses and experimental results. The results show that the scheme can produce desired dynamics for the current control and guarantees balanced current sharing between the winding sets. In addition, the proposed solution is capable of reducing current harmonics produced by the internal structure of the machine. This problem is, however, only partly solved since complete elimination of harmonic components is not achieved. Nevertheless, the suggested control scheme overcomes many of the disadvantages found with other control solutions. Improved control performance allows the full benefits of dual three-phase drives to be utilized even in demanding applications.