Hybrid distribution transformer (HDT) is a promising device for constructing the future active distribution network. To overcome the limitations of the existing HDT control schemes, a compound control scheme is proposed for a HDT with improved circuit design. In this design, the voltage source converter (VSC) for low-voltage (LV) side voltage regulation is moved to the medium-voltage (MV) side. The compound control scheme is developed based on the dynamic model of this new HDT, which explicitly considers the external disturbances. In this control scheme, two compound controllers are established to regulate the grid current and load voltage, respectively. For each compound controller, feed-forward loops are integrated with the PI regulator, thus suppressing the disturbances. The key feature of this control scheme is that, by using the feed-forward loops, the effect of external step disturbance can be equivalently weaken to an impulse disturbance and, hence, the system robustness can be improved. Simulation and experimental results validate the effectiveness of the proposed control scheme.

The effects of multi-phase and multi-layer windings of the 12-slots 10-poles surface-mounted permanent magnet synchronous machines (SPMSMs) on eddy current losses in permanent magnets (PMs) are mainly investigated using the 3-D finite element analysis in this paper. Eddy current losses in PMs considering its axial segmentation are also analyzed. It is demonstrated that dual three-phase four-layer (DTP-FL) winding layout has the minimum value of eddy current losses in PMs, when segmentation number $N = 4$. It is because DTP-FL winding has smaller magnitude of high-order magnetomotive force harmonics relative to other four winding layouts. The average torque and torque ripple changing with multi-phase, multi-layer, and axial segmentation are also studied. Finally, the no-load and load experiment platform for an axial flux integrated-starter generator with DTP-FL winding and radial segmented PM are established in order to validate the proposed method under power generation mode.

This article takes 12-slot/10-pole axial flux permanent magnet (PM) synchronous machine (AFPMSM) with fractional-slot concentrated windings and yokeless and armature (YASA) topology as the research object. Winding magnetomotive force (MMF) of three-phase double-layer layout is analyzed by three kinds of methods, which are star diagram method, winding function method, and holographic spectrum method. The analysis results of finite-element method (FEM) show that the three methods are effective and consistent in analyzing winding MMF. Comparative analysis of iron loss density and B-H magnetizing curves of four typical iron materials are studied. B-H hysteresis loops of silicon steel sheet and soft magnetic composite are measured by magnetizing and measuring equipment to validate iron core per unit mass. The three-dimensional FEM is used for analyzing eddy-current loss in PMs considering radial segmentation. Finally, an AFPMSM prototype is manufactured adopting YASA topology and segmented PM. Load experiments show that solid-liquid coupling computational fluid dynamics model can precisely predict temperature distribution of AFPMSM. Improved cooling jacket is beneficial to afford large current load.

Eccentricity in a permanent magnet synchronous motor (PMSM) can cause additional electromagnetic forces and resolver error, which in turn can lead to an aggravation of vibration and noise in the electric drive system. In this paper, the additional electromagnetic forces and the resulting vibration and noise under the conditions of the three-dimensional (3-D) static and dynamic motor eccentricities, the resolve error, and the coupling between these faults, are analytically derived and analyzed, with special emphasis on the coupling effect of the motor eccentricity and resolver error. The results of the present theoretical analyses agree well with those from the finite element simulations and the experimental measurements. It can be concluded from the results that the coupling between the 3-D motor eccentricity and the resolver error will induce additional electromagnetic forces with much more diverse spatial orders and frequencies.

A novel 24 kW 12‐slots/10‐poles axial‐flux permanent‐magnet synchronous machine (AFPMSM) with external rotor motor applied to the large electric motorcycle is introduced in this study, which has the characteristics of the yokeless and segmented armature for power density improvement. The hierarchical method is used for calculation of stator iron core loss based on the analytical solution of air‐gap flux density, which cuts the prototype into many equivalent linear motor slices in the circumferential direction. A major advantage of hierarchical methods over traditional iron core loss calculation is its higher accuracy and rapidity. Then a lumped parameter T‐type thermal network model is presented for AFPMSM temperature rise calculation. A 3D liquid–solid coupling model is compared with the 2D T‐type lumped parameter thermal network. Finally, a temperature rise measurement platform is established to verify the above‐mentioned methods. Testing result shows that the hierarchical method and T‐type thermal network have a higher accuracy to predict each part temperature.