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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.

A 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 be driven by 120deg square-wave voltage and use pulse-width modulation (PWM) patterns in two-phase feeding schemes to control the speed of the machine. This paper introduces four PWM modes that used the FRM control system and analyzes the effects of four different PWM modes on the iron loss using a 2-D time-stepped voltage source finite-element method. The iron loss is calculated from the time variation of the magnetic field distribution

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 describes the effect of pulsating current generated by back-electromotive force (BEMF) current of switch-off phase in flux-reversal machine (FRM) which is driven by 120deg square wave voltage sources. A two-dimension time-stepped voltage source finite element analysis using a direct convergence method is proposed to analyze an electromagnetic field and the BEMF current. To prove the propriety of the proposed analysis method, we build the prototype FRM and a digital signal processor (DSP) installed controller as a set for the experiment

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 flux reversal machine (FRM) is a new brushless doubly salient permanent-magnet machine. Its operation is similar to that of the brushless dc motor, so it can be driven by 120/spl deg/ square wave voltage and use pulsewidth modulation (PWM) pulse patterns in two-phase feeding scheme to control the speed. This paper introduces PWM modes used in FRM control system, and analyzes their different influences on the performances of the FRM using a time-stepped voltage source finite-element method. To prove the propriety of the proposed analysis method, digital signal processor (DSP) installed experimental devices are equipped and the experiment is performed.

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.

A novel permanent-magnet flux-concentration-type linear oscillatory actuator (LOA) for a compressor is analyzed in this paper. The losses of a flux-concentration-type LOA which is driven by sinusoidal and rectangular-shaped current are compared using finite-element method (FEM). In this computation, the equation of magnetic field is coupled with the equation of the driving electric circuit and the equation of motion. The results are compared with respect to iron losses. The eddy-current loss and hysteresis loss of both the sinusoidal current and rectangular current was calculated using two-dimensional FEM.

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 paper introduces a set of static and dynamic experiments to more fully characterize a linear permanent magnet (PM) oscillatory machine. The proposed set of tests was performed on a PM brushless linear oscillatory machine with surface PM and PM flux concentration movers, respectively. Though the testing arrangement allows for it, temperature, noise and vibration have not been investigated in this paper.

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 presents an approximate optimization that is able to determine optimal geometric and electrical design variables of switched reluctance motor. In order to reduce torque ripple that causes noise and vibration, the approximate optimum design has been investigated by means of combining a progressive quadratic response surface method (PQRSM) and a time-stepping finite element method considering drive circuit. The PQRSM is more effective than conjugate gradient method in torque ripple minimization.

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.