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The spoke‐type arrangement of permanent magnets (PMs) in rotor of Vernier PM (VPM) machines was first introduced in a dual‐stator topology to overcome low‐power drawback of VPM machines. However, this structure is mostly applicable for high‐power motor drives. A non‐ferromagnetic spoke array VPM generator with a special rotor structure for small‐scale wind turbine generator is presented. The leakage flux lines tend to be aligned with the main flux routes due to a special design of flux barriers in end portion of PM housings. High torque‐density, low weight, torque‐speed curve with a wide constant torque region, promising efficiency, and power factor are the advantages of the proposed machine. An Equivalent‐Magnetic‐Network (EMN) model is established for predicting the complex behaviour of flux lines and operating quantities of the proposed structure with reasonable accuracy. The contribution of the modelling method includes a special mesh cell for the air‐gap permeance network to more accurately capture the flux routes, continuous positioning method for omitting spikes on post‐processing waveforms due to numerical errors, and a stable solving flowchart with a high convergence rate. The validity of the EMN model is validated by comparing the operating waveforms of the machine with the corresponding waveforms obtained by the finite element and experiments. The cover image is based on the Research Article Design of a non‐ferromagnetic spoke array Vernier permanent magnet generator with iron‐bar based on enhanced equivalent magnetic network model by Mehrage Ghods et al., https://doi.org/10.1049/elp2.12272. [ABSTRACT FROM AUTHOR]

Thedual-winding outer-rotor Vernier-permanent-magnet (VPM) generator, which possesses two-phase-windings inserted in the stator core with two slot levels of shallow and deep and saturable tooth-tips with narrow regions, has already been presented and studied for the traffic-enforcement-camera applications. The flux lines routes in this VPM generator have a complex pattern because of existing flux modulation poles, deep slots and fringing and leakage fluxes in different parts. Hence, the accurate analytical modeling of this special machine requires an advanced method. To fulfill this aim, equivalent-magnetic-network (EMN) model of the VPM generator is extracted in this article by combining reluctance-network-model and magnetic-equivalent-circuit. simpler mathematical equations and lower computational burden are advantages of the proposed EMN model in comparison with finite-element (FE) model. The method of finding the rotor position based on the region selection and considering the effect of the slot permeances and magnetic saturation under both no-load and on-load operating conditions are the other novelties highlighted. Also, especial pentagonal-shape meshes with unequal sides’ lengths and angles are proposed for the air-gap meshing, which can effectively model the complex flux routs. Test results and FE simulations are used to validate the accuracy of the developed EMN for the investigated VPM generator. [ABSTRACT FROM AUTHOR]

Linear permanent magnet Vernier machines (LPMVMs) is an attractive solution for stroke and direct-drive applications. Several LPMVM topologies have been presented for different applications that operate based on magnetic flux modulation. LPMVMs have some advantages including high force, and torque density at low speeds. This paper introduces a double-excited linear Vernier machine for wave energy conversion. To model the machine, finite element analysis and nonlinear equivalent network model are used. To improve the accuracy of the model and compact the network, a new meshing method is proposed. For better continuity in the output waveforms of the machine, special positioning is utilized. The end-effect is modeled using two separate networks. Finally, the modeling and simulation results are compared with each other and validated experimentally. [ABSTRACT FROM AUTHOR]

Stator and rotor structures, arrangement of permanent magnets (PMs), and type of coils of PM Vernier machines are reviewed and classified. Then, electromagnetic performance and the energy conversion process in the machine are described. Determination of magnetic field distribution and air‐gap permeance of the machine is very complicated than that of other PM machines. Impacts of variations of dimensions in the machine such as the number of modulators on the modulus width and the rotor PMs thickness on the load characteristics (cogging torque, back‐EMF, and power factor) are investigated. In addition, principles of flux modulation machines operation are presented and the shape and dimensions of the modulators are optimized. The two‐phase and four‐phase winding types are used to improve the output power of the machine. Finally, a 150 W PM Vernier generator is designed and prototyped to feed the road speed camera. [ABSTRACT FROM AUTHOR]

Summary: Although Vernier machines have been introduced a long ago, their description, applications, and design improvement have been recently proposed. This paper reviews different types of linear Vernier machine. Their description and theoretical base of the performance are presented. The performance of the motor is improved by reducing the cogging force, increasing the power factor, and enhancing force density. Stator and translator structures, the arrangement of magnets, and the type of coils of permanent magnet (PM) Vernier machines are reviewed and classified. Then, the electromagnetic performance prediction and energy conversion process in the machine is described. The magnetic field distribution and air gap permeance analysis indicate that such analysis is very complicated than that of other PM machines. Impacts of variations of dimensions in the machine such as the number of modulators on the modulus width and thickness of the mover PMs on the load characteristics (cogging torque and Back‐EMF) are addressed. Besides, principles of operation of flux modulation machines are presented and the shape and dimensions of the modulators are optimized. Finally, a 150 W linear PM Vernier generator is designed and prototyped to the energy harvested by the ocean wave. [ABSTRACT FROM AUTHOR]

The cover image is based on the Review Article I Single stator-single rotor permanent magnet Vernier machine topologies for direct-drive applications: Review and case study i by Jawad Faiz et al., https://doi.org/10.1002/2050-7038.13240. [Extracted from the article]