This paper proposes a new type of vernier machine with permanent magnets (PMs) on both sides of rotor and stator. The rotor is of the flux concentrating structure and the stator has also PMs between the flux modulation poles. Compared with the other types of vernier machine, the proposed model has a huge increase in the induced voltage and developed torque at the same size. This shows the possibility of the new suggested machine to the direct-drive applications such as wind-power generators and in-wheel motors.

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.

This paper investigates the characteristics of the radial force density according to the shapes of the flux modulation poles (FMP) in a surface-mounted vernier machine (SPMVM). The air-gap flux density harmonics obtained from the finite-element analysis method are analyzed using the analytical equations derived from the magnetomotive force and the air-gap permeance distributions. Then, in order to find the radial force density harmonics that generate the exciting force on the stator, the spatial orders and the angular frequencies of the radial force density harmonics are calculated by using the Maxwell stress tensor method. The analysis results show that the permeance harmonics generate the radial force density harmonics, but the resulting harmonics of the radial force density are time-invariant in the spatial domain. Consequently, the variation of the FMP shape can improve the torque characteristics of the SPMVM without the increase of the exciting force on the stator core.

This article proposes the design and driving mechanism of a single drive motor integrated electromechanical actuator system for the application in computer numerical control (CNC) lathe machines. The electromechanical actuator is designed in such a way that it can replace the conventionally used hydraulically powered headstocks of the lathe machine. To achieve a drawbar thrust of 50 kN and a spindle speed of 4000 r/m, a detailed design with an explanation of different internal parts of the electromechanical actuator is presented. The production ready model was simulated to select the safety factor of the whole system and to enquire the amount of deformation when 50 kN thurst is generated. A prototype is manufactured based on the analysis model and is tested for different modes of operation. The experimental results validate the capability of the electromechanical actuator to produce the require drawbar thrust of 50 kN and spindle speed of 4000 r/m.

Performance Comparison of PM Synchronous and PM Vernier Machines Based on Equal Output Power per Unit Volume Direct-drive;Efficiency;PM synchronous machine;PM vernier machine;Output power; This paper compares the performances of permanent-magnet synchronous (PMS) and permanent-magnet vernier (PMV) machines for low-speed and high-torque applications. For comparison with the PMS machines, we consider two types of the PMV machine. The first one has surface-mounted permanent magnets (PMs) on the rotor and the other has PMs inserted on both sides of the stator and rotor. The PMS and PMV machines are designed to meet the condition of equal output power per unit volume. We analyze the magnetic fields of the machines using a two-dimensional finite element analysis (FEA). We then compare their performances in terms of the generated torque characteristics, power factor, loss, and efficiency.