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Recently, the permanent magnet vernier machine (PMVM) is studied extensively because of its merits such as the high torque density. Similar to the magnetic gears, the PMVM operates on the principle of flux modulation. However, there is a distinct difference in between the two as unlike the magnetic gear, in case of PMVM, the winding MMF harmonics rotates with different speed as that of the fundamental. As a result, these harmonics are capable of making a working magnetic field by interacting with different permeance harmonics. Therefore, this paper aims to provide an analytical explanation of this whole process, which is helpful to understand the effect of the flux modulation on the output torque. Furthermore, using the analytical formulation, this work finds the optimal geometric parameters which maximize the working magnetic field and hence the torque. A detailed analysis of the PMVM with the doubly salient structure is studied and the performance is analyzed using the finite element method (FEM) and the experimental setup. The FEM and experimental results verify the maximum torque production by using the optimal geometric parameters in the PMVM modeling, obtained using the analytical formulation. [ABSTRACT FROM AUTHOR]

Axial‐flux permanent magnet synchronous machines (AF‐PMSM) using printed circuit board (PCB) windings are attracting interest because of an increased demand for machines with thinner geometries. A critical element in designing these machines is the choice of its PCB winding which should ensure high‐performance characteristics with an efficient use of the PCB surface. However, there is a gap in the knowledge regarding the performance of different PCB topologies. The research reported here is motivated by the need to compare common wave‐type PCB windings stator topologies. Accordingly, overlapping parallel wave, non‐overlapping radial wave and overlapping radial wave PCB winding topologies are assessed, using finite‐element analysis, and compared based on their key performance characteristics such as the generated back‐electromotive forces, inductances and electromagnetic torque. The PCB winding that provides the best torque production is then chosen and manufactured. Experimental tests on the prototyped PCB AF‐PMSM provide validation. [ABSTRACT FROM AUTHOR]

This paper presents an accurate initial pole position (IPP) estimation method for a surface mounted permanent magnet synchronous motor (PMSM) without the use of pole sensors. To estimate the IPP, the proposed method uses the concept of reference frame. In this method, three torque commands, separated by 45° electrically from each other, are applied to the PMSM. Using the reference torque commands, moving distances are measured and transformation matrix is applied to eliminate the load torque term. Finally, the IPP is determined using the secant method. The IPPs under no load and at specific loaded condition are measured. The result of the load condition is compared with the previously proposed two reference frame method. The proposed method gives better result under load condition, compared with the two reference frame method, which fails to give satisfactory result under load condition. [ABSTRACT FROM AUTHOR]

This paper proposes a design method for the flux modulation poles (FMPs) formed on the stator of surface-mounted permanent magnet vernier machines (SPMVM) considering the winding configurations. In three types of the SPMVM with the different winding configurations, the FMP shapes to maximize the output torque are optimized by employing the analytical equations for the magneto-motive force (MMF) due to the windings, permeance, and flux density in the air-gap. Then, the validity of the optimal shapes for the FMPs is verified by the finite element analysis. It is found that the optimal FMP shapes are designed differently in the three types of the SPMVM and increase the output torque by different ratios according to the winding configurations. In addition, the experimental results for the prototype show that the proposed method can optimally design the FMP shape by analyzing mathematically the effects of the winding configuration and the FMP shape on the output torque of the SPMVM. [ABSTRACT FROM AUTHOR]