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A Dual three-phase winding configuration in a 12-slot 10-pole Brushless Alternative Current Synchronous Motor (BLAC) has been adopting in electrical power steering systems. The main aim of this winding configuration is to get a fault tolerance capability when the motor is a failure. Different arrangements of the coils of the windings are possible to separate the three-phase winding. In this paper, we investigate the effect of the various winding configurations for the fault tolerance on the iron losses of the BLAC motor. To calculate accurate iron losses, we use the instantaneous distribution of magnetic flux from a two-dimensional finite-element method. As a result, we suggest the most effective winding configuration to make the BLAC motor efficiency in the event of the fault.

정현파 전류 구동의 분수 슬롯을 갖는 영구자석 동기 전동기는 코깅 토크 저감 측면에서 장점을 갖기 때문에 하이브리드 및 전기자동차의 전기조향장치시스템에 적용이 가능하다. 이러한 전동기는 그 목적에 따라 이층권 및 단층권 등의 다양한 형태의 고정자 권선 방법을 적용하고 있는데, 본 논문에서는 여러 가지 고정자 권선 방법에 따른 영구자석 동기 전동기의 철손 특성을 정밀 분석하였다. 이를 위해 시간 고조파를 고려한 철손 해석 기법을 사용하였으며, 유한요소 해석에 의해 얻어진 순시 자속밀도로부터 히스테리시스손 및 와전류손을 계산하였다. 해석 결과, 각 권선 방법에서 대부분의 철손은 고정자에서 발생하였으며, 철손밀도는 자계의 변화가 교번자계 특성을 갖는 치와 요크에서보다 회전자계의 특성을 갖는 고정자 치 끝단부에서 가장 높게 분포하였다. 또한 부하에 따른 철손은 정격부하 이하에서 단층권이 이층권에 비해 철손이 작았으며, 부하가 증가할수록 자기회로의 포화로 인해 단층권에서 급격히 철손이 증가함을 알 수 있었다.

This paper proposes an analytic model for four-switch inverter (FSI)-driven wye (Y) or delta (Δ)-connected motors with a current ripple reduction algorithm. FSIs employ four switches in controlling three-phase load instead of using six switches. They have split dc-link stage, and due to this inherent structure there exists the voltage difference between upper and lower capacitors, which results in distortion of the inverter output voltage. To study characteristics of FSIs, this paper presents an advanced simulation models of FSI-driven control system for 3-phase motor that can has a wire connection either Y or Δ. In addition, this paper introduces a current ripple reduction scheme that mitigates degradation of control performance due to the voltage difference between the dc-link capacitors. The validity of the proposed method and the analytic model is verified by simulations and experiments carried out with 1-HP induction machine with Y or Δ-connection

This paper presents a nonlinear sliding mode control (SMC) scheme with a variable damping ratio for interior permanent magnet synchronous motors (IPMSMs). First, a nonlinear sliding surface whose parameters change continuously with time is designed. Actually, the proposed SMC has the ability to reduce the settling time without an overshoot by giving a low damping ratio at the initial time and a high damping ratio as the output reaches the desired setpoint. At the same time, it enables a fast convergence in finite time and eliminates the singularity problem with the upper bound of an uncertain term, which cannot be measured in practice, by using a simple adaptation law. To improve the efficiency of a system in the constant torque region, the control system incorporates the maximum torque per ampere (MTPA) algorithm. The stability of the nonlinear sliding surface is guaranteed by Lyapunov stability theory. Moreover, a simple sliding mode observer is used to estimate the load torque and system uncertainties. The effectiveness of the proposed nonlinear SMC scheme is verified using comparative experimental results of the linear SMC scheme when the speed reference and load torque change under system uncertainties. From these experimental results, the proposed nonlinear SMC method reveals a faster transient response, smaller steady-state speed error, and less sensitivity to system uncertainties than the linear SMC method.

This paper proposes an online gain tuning algorithm for a robust sliding mode speed controller of surface-mounted permanent magnet synchronous motor (SPMSM) drives. The proposed controller is constructed by a fuzzy neural network control (FNNC) term and a sliding mode control (SMC) term. Based on a fuzzy neural network, the first term is designed to approximate the nonlinear factors while the second term is used to stabilize the system dynamics by employing an online tuning rule. Therefore, unlike conventional speed controllers, the proposed control scheme does not require any knowledge of the system parameters. As a result, it is very robust to system parameter variations. The stability evaluation of the proposed control system is fully described based on the Lyapunov theory and related lemmas. For comparison purposes, a conventional sliding mode control (SMC) scheme is also tested under the same conditions as the proposed control method. It can be seen from the experimental results that the proposed SMC scheme exhibits better control performance (i.e., faster and more robust dynamic behavior, and a smaller steady-state error) than the conventional SMC method.

Flux-reversal machine (FRM) is cost effective and suitable for mass production due to its simple structure. However, there is a notable permanent magnet flux leakage which deteriorates the performance. To compensate this drawback with a design method, an Inset-Permanent-Magnet-Type FRM (ITFRM) has been proposed. The ITFRM has permanent magnets perpendicular to the stator teeth surface, and thus, is much more difficult to demagnetize. In this paper, we deal with the iron losses and irreversible permanent magnet demagnetization characteristics of the ITFRM according to various design variables and driving conditions. To analyze the characteristics, a two-dimensional finite-element method (2D-FEM) considering nonlinear analysis of permanent magnets is used. As a result, we propose the design variables that have the largest effects on the iron losses and irreversible magnet demagnetization.

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.

In this paper, a digital speed regulator system design method is developed for a permanent magnet synchronous motor (PMSM). Firstly, an accurate approximate discrete-time model is proposed for a PMSM considering its inherent nonlinearities. Based on the discrete-time model, a digital acceleration observer as well as a digital speed regulator is designed. The exponential stability of the augmented control system is analyzed. The proposed digital speed regulator system is implemented by using a TMS320F28335 floating point DSP. Simulation and experimental results are given to verify the effectiveness of the proposed method.

Many different converter topologies have been developed with a view to use the minimum number of switches in order to reduce construction costs. Among this research, the four-switch converter topology with a novel PWM control technique based on the current controlled PWM method is thought to be a good solution. In this paper, a two dimensional time-stepped voltage source finite-element method (FEM) is used to analyze the characteristics of a Flux-Reversal Machine (FRM) with a 4-switch converter. To validate the proposed computational method, a digital signal processor (DSP) installed controller and prototype FRM are built and experiments performed.

This paper proposes a fuzzy speed tracking controller and a fuzzy rotor angular acceleration observer for a surface-mounted permanent magnet synchronous motor (SPMSM) based on the Takagi-Sugeno (T-S) fuzzy model. The proposed observer-based controller is robust to load torque variations since it utilizes rotor angular acceleration information instead of the load torque value. Linear matrix inequality (LMI) sufficient conditions are given to compute the gain matrices of the speed tracking controller and the observer. In addition, it is mathematically verified that the proposed observer-based control system is asymptotically stable. Simulation and experimental results are presented to confirm that the proposed control algorithm assures a better transient behavior and less sensitivity under model parameter variations than the conventional PI control method.

This paper presents a fuzzy PD speed control scheme for the robust speed tracking of a permanent magnet synchronous motor (PMSM). Motivated by the common control engineering knowledge that transient performance can be improved if the P gain is big and the D gain is small in the beginning, a linearizing control scheme with a fuzzy PD controller is proposed. The global system stability is analyzed and the proposed control algorithm is implemented using a TMS320F28335 DSP. Simulation and experimental results are given to verify the effectiveness of the proposed method.

This paper proposes a new adaptive speed controller to achieve a robust speed control of a permanent magnet synchronous motor(PMSM). The proposed adaptive regulator does not require any information on the motor parameter and load torque values, so it is very insensitive to model parameter and load torque variations. Also, the stability of the proposed adaptive control system is proven. To validate the robustness of the proposed adaptive speed controller, both simulation and experimental results are provided under motor parameter and load torque variations. It is clearly demonstrated that the proposed adaptive regulator can accurately control the speed of permanent magnet synchronous motors.

The authors consider the speed controller design problem for a permanent magnet synchronous motor (PMSM). Based on the Takagi–Sugeno fuzzy approach the authors design a fuzzy speed controller as well as a fuzzy load torque observer. The authors derive sufficient conditions for the existence of the controller and the observer in terms of linear matrix inequalities (LMIs). The authors give LMI parameterisations of the gain matrices. The authors also derive LMI conditions for the existence of the fuzzy speed controller and the fuzzy load torque observer guaranteeing α-stability, quadratic performance and H2/H∞ performance. The authors implement the proposed load torque observer-based fuzzy speed control system by using a TMS320F28335 floating point DSP, and give simulation and experimental results to show the effectiveness of the proposed method.

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.

This paper introduces two types of magnetization, and reports the effect of the magnetization direction on the iron loss in a brushless DC (BLDC) motor using a 2-D time-stepped voltage source finite-element method (FEM). The iron losses were found to consist of hysteresis and eddy current loss, which were calculated from the time variation of the magnetic field distribution. To confirm the analysis, a prototype BLDC motor was constructed with a sintered ferrite magnet. The analysis and experimental results suggest that the magnetization direction has a significant effect in terms of the iron loss characteristics of the BLDC motor.

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.

Flux-reversal machine (FRM) is a new doubly-salient stator-permanent magnet (PM) machine with flux linkage reversal in the stator concentrated windings. The simple structure makes it cost effective and suitable for mass production. Also, the FRM has permanent magnets parallel to the stator magnet flux lines and thus is much more difficult to demagnetize. However, in actual application fields such as factory automation and a home appliance, the FRMs adopt permanent magnets with a low intrinsic coercivity and a narrow thickness. In this paper, we especially concentrate on the irreversible demagnetization characteristic of the permanent magnet. To analyze the characteristics of the FRM, a two-dimensional finite-element method (2D FEM) considering the nonlinear analysis of the permanent magnet is used.

In this paper, we introduce two kinds of magnetization type, and investigate the effect of its direction on the iron loss in brushless DC (BLDC) motor using a 2-D time-stepped voltage source finite-element method (FEM). The iron losses consist of hysteresis and eddy current loss is calculated from the time variation of the magnetic field distribution. As a result, the magnetization direction that is more advantageous in terms of the iron loss characteristic of the BLDCM is suggested.

Flux-reversal machine (FRM) is a new brushless doubly salient permanent magnet machine proposed with the same aim of combining the advantages of the switched reluctance motor (SRM) and the permanent magnet brushless DC motor (BLDCM). This paper analyzes the influence of PWM modes on the iron loss of the FRM using a two dimensional time-stepped voltage source finite-element method (FEM). The iron loss is calculated from the time variation of the magnetic field distribution. To produce the PWM pulse patterns and perform the experiment, the digital signal processor (DSP) installed controller and the prototype FRM with an Nd-Fe-B magnet are built.

The large demagnetizing currents in flux-reversal machine (FRM) are generated by the short-circuited of stator windings and the fault of a drive circuit. So, irreversible magnet demagnetization occurs due to the external demagnetizing field by these currents. In this paper, we deal with the effect of design variables on irreversible magnet demagnetization in the FRM using two-dimensional finite-element method (2D FEM). The nonlinear analysis of a permanent magnet is added to 2D FEM to consider irreversible demagnetization. As a result, it is shown that magnet thickness and rotor teeth width are the most important geometrical dimensions of the FRM in terms of irreversible magnet demagnetization.

Research interest in the switched reluctance motor (SRM) has grown significantly in recent years because of their apparent advantages such as simple construction, fault tolerance and mechanical robustness. In this paper, we deal with the effect of design variables on irreversible magnet demagnetization in the FRM using two-dimensional finite-element method (2-D FEM). The nonlinear characteristic of the permanent magnet is considered as well as that of a magnetic core on each B-H curve. From the analysis results, the most important geometrical dimensions are suggested in terms of irreversible magnet demagnetization.

A novel permanent magnet (PM) flux concentration type linear oscillatory actuator (LOA) for a compressor is analyzed in this paper. The characteristics of the flux concentration typed LOA, which is driven by sinusoidal and rectangular input 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 in respect of iron losses. The eddy current loss and hysteresis loss of both the sinusoidal input and rectangular input was calculated using 2D-FEM.

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.

The large demagnetizing currents in a single-phase line-start permanent magnet motor are generated by a starting and locked rotor condition. Thus, irreversible magnet demagnetization occurs due to the external demagnetizing field by these currents. In this paper, we present the phenomenon of the irreversible magnet demagnetization using two-dimensional finite-element method (2-D FEM). The nonlinear analysis of a permanent magnet is added to 2-D FEM to consider irreversible demagnetization. As a result, design techniques which are effective in avoiding irreversible demagnetization are proposed.

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.