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In this paper, the 6-switch inverter for the Flux-Reversal Motor (FRM) has been presented and compared to the 4-switch inverter for the FRM, which is more popular in cost effective applications. To analyze the FRM, we adopted the two-dimensional time-stepped voltage source finite element method (FEM) that uses the actual pulse width modulation (PWM) voltage waveforms as the input data. As the FRM characteristic analysis of actual pwm voltage input, the torque ripples and iron losses (eddy current and hysteresis loss) of the FRM can be precisely calculated. With the simulated and experimental results, the performance and limitations of the 4-switch FRM which is the cost effective drive compared to the 6-switch FRM drive are provided in more detail.

This paper presents a unique method for simulating permanent magnet motors without time-consuming numerical methods used in the conventional magnetic circuit method. The conventional method gives us average values like torque and power over specified periods of time, but it is usually very difficult and time-consuming to obtain instantaneous characteristics like cogging torques and torque ripples. The convolution operations method we present, however, considers relative angle variations of stator magnetic circuits and rotor magnetic circuits. As a result, it makes uses of instantaneous values possible. The authors compare the new method with the coventional method and verify that calculating cogging torque values and back-emf values is possible with the proposed new convolution method.

Flux-reversal machine (FRM) is a new doubly salient stator-permanent magnet (PM) machine with flux linkage reversal in the stator concentrated windings. It can operate in both motoring and generating modes. Its simple structure makes it cost effective and suitable for mass production. However, there is notable permanent magnet flux leakage which deteriorates the torque ability of the FRM. In this paper, a novel design to improve the performance of an FRM is proposed. The proposed FRM has permanent magnets parallel to the stator magnet flux lines and thus is much more difficult to demagnetize. To analyze the characteristics of the proposed FRM, a two-dimensional finite-element method (2-D FEM) is used. The prototype FRM is also built to prove the advantage of the new design method. From the analysis and experimental results, it is shown that the proposed FRM has an improved performance.

The flat-type vibration motor has an axial-gap structure. Analyzing axial-gap motors with the two-dimensional (2-D) finite-element method is very difficult because we have to define the analysis surface as a cylindrical surface. In order to simulate the flat-type vibration motor, we have developed new equations of calculation for the torque of the motor, which is uses a 2-D grid model. We have measured the load torque of the vibration motor which is used for the motion transient analysis. The simulated vibration characteristic is compared with experimental value

This paper presents a characteristic analysis of switched reluctance motor (SRM) considering hard chopping and dc link voltage ripple by using time-stepped voltage source finite element method in which the magnetic field is combined with drive circuit. We also examine the influence of freewheeling diodes and dc link voltage ripple on the performance of a SRM such as torque ripples and radial force on the surface of the teeth. The freewheeling diodes and dc link voltage ripples must be taken into account in predicting the performance of the SRM.

The dynamic characteristics of a flux reversal machine are analyzed using finite-element method coupling with the equation of the driving electric circuit and the motion equation. In this computation, sine-wave and rectangular-wave current drives are used as the driving conditions like a brushless motor, and the results are compared in respect of torque ripple and iron losses. Considering the torque ripples, driving a skewed motor with rectangular wave input is cost effective. However, among the parts of the motor, the rotor experienced high variations of the flux, which results in high losses.

The cogging torque of the flux-reversal machine (FRM) may cause some problems like noise and vibration of the motor. By FEM analysis of the cogging torque of FRM, a noticeable feature was found that the rotor teeth width increases, phase and magnitude of the cogging torque varies. So, the rotor teeth pairing method is proposed for reducing the cogging torque of FRM. In this method, we made a rotor which has two different tooth widths and measured the cogging torque of the motor. From the result, we can see that the simulation result is well matched with the measured result and the proposed method is feasible.

This paper proposes the single-phase flux-reversal motor for a vacuum cleaner. The circuit parameters are determined by using both finite-element method and experimental measurements while a simulation was done by using an equivalent circuit model to derive the dynamic characteristics. Due to the inductance of the coil of high-speed drives, a phase difference occurs between the current and the electromotive force which produces a negative torque that degrades the output. Through simulation, the turn-on angle and turn-off angle that minimize the negative torque are found and simulation results will be compared with the results of the experiment.

The three-phase flux reversal machine (FRM) is a doubly-salient stator-permanent magnet machine with flux linkage reversal in the stator three-phase concentrated windings. It can operate in both motoring and generating modes. In this paper, we identify stator/rotor geometrical design variables that influence the cogging, interaction torques, and winding flux linkage using a two-dimensional finite-element method and the flux-magnetomotive force diagram technique. Also, the novel design to improve the performance of the FRM is studied both theoretically and experimentally.

This paper deals with the characteristic analysis of a brushless dc motor (BLDC) taking into consideration the freewheeling diodes and dc link voltage ripple using a time-stepped voltage source finite-element method. By comparing the experimental results, the authors show that the proposed computational method is useful for the analysis and design of a BLDC motor. They also examine the influence of freewheeling diodes and dc link voltage ripples on the performance of a BLDC motor such as torque ripples and radial force on the surface of the teeth.

This paper introduces flux-reversal machine (FRM) and presents the design of a FRM to reduce the cogging torque. The effect of the design parameters on the characteristic and cogging torque is analyzed by finite element method (FEM). The considered design parameters are bifurcated teeth, chamfered magnet poles, chamfered rotor tooth tips and rotor skewing. As a result, we can find the optimum model reduced cogging torque and torque ripple in 6/8 FRM.

This article introduces a single phase flux-reversal machine (FRM) and presents the design method to improve its starting torque. The effects of the design parameters on the characteristic and starting torque are analyzed by the finite element method. The design variables considered are tapered airgap, stepped airgap, slotted teeth, and asymmetric PM width. As a result, we can find the best model in producing starting torque of a single phase 2∕3 FRM.