Control of a Segmented Three-Phase Synchronous Motor With Highly Coupled Subwindings

Abstract

This article addresses the control issue of a structure enabling the segmentation of three-phase electric drives. The proposed segmentation process offers an additional degree of freedom in terms of voltage rating for power electronics but results in a three-phase system with highly coupled sub-windings. Thus, for such a segmented motor, the true challenge lies in controlling the machine global electromagnetic torque while balancing the power among the different inverters. To tackle this issue, the dq standard synchronous frame is extended to common and differential modes. This approach enables to design a suitable control structure based on an analytical model and physical considerations. The developed model is calibrated with realistic numerical values obtained from a finite element analysis. Finally, an experimental setup allows developing a proof of concept which shows the interest of the proposed control method compared to a standard multiple dq-frame method. The key finding is that the above-mentioned control objective of the segmented synchronous motor can be achieved without additional inductors and despite the severe constraint imposed by such highly coupled segmentation.

Analysis of DC-Link Low-Frequency Current Harmonics in Multi-Source Multi-Three-Phase Electric Drives

“…However, in the specific case of a multi-three-phase PMSM, an additional transformation is required to diagonalize the L 3×3ph if the coupling factor k n is significant [37,38]. In [7], a common and differential mode transformation P Σδ is proposed.…”

“…Reference values for winding resistance and inductance are considered in this article, obtained from averaged measurement value of a HC PMSM platform [7,8]. Since the three multi-port winding structures have exactly the same number of turns per phase per sub-winding, the same phase resistance value is assumed for all three winding structures.…”

“…Various multi-three-phase structures can be achieved. In the case of permanent magnet synchronous motor (PMSM) drives, as illustrated in Figure 1, three main winding structures can be identified: multi-sector winding [1,2], multi-three-phase winding [3][4][5], and highly coupled winding [6][7][8][9]. One problem of using multi-three-phase drives is the DC-link design.…”