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This paper presents the effect of magnetization of the permanent magnet on torque pulsation and performances of the permanent magnet brushless DC (PM BLDC) motor. Three common types of PM magnetization field patterns, radial, parallel and sinusoidal magnetization, are applied to the electromagnetic field system and investigated the motor performances and output torque profiles. The testing and simulation...
This paper presents the analysis method for a linear ultrasonic motor using radial and nonaxisymmetric vibration modes of an annular plate. The displacement of the stator is analyzed by 3D finite element method, and the contact between the stator and the mover is analyzed by analytic method. The analysis results of the model with stator radius of 10.00 mm and thickness of 1.00 mm is compared with...
In general, an analysis of the claw-pole type alternator was performed through 3 dimensional finite element analysis (3D FEA) or magnetic equivalent circuit (MEC). However, 3D FEA needs much computation time and many computer memories. Also MEC has the difficulty to define the main flux path on electric machine including the complex shape. In this paper, to overcome this shortcoming, we propose an...
One position controlling source using sinusoidal wave by CPLD through linear amplifier technique for driving ring-type traveling-wave ultrasonic motor with 30 mm diameter of the stator (RTWUSM30) has been proposed and designed in this paper. The driving and controlling signals can be adjusted the frequency, the phase, the amplitude, and the phase difference of the two sin wave exciting signals through...
The researches on vibration behavior of axial flux permanent magnet synchronous motor (AFPMSM) are presented in the paper. The main work includes calculation of axial fluctuating electromagnetic forces caused by various harmonics in air gap with Maxwell stress tensor method in 3-D magnetic field. The principle resulting in axial electromagnetic force is deduced by numerical algorithm. The axial electromagnetic...
This paper reviews the concepts, developments and applications of the novel permanent magnet brushless machines having magnets and windings in the stator with particular emphasis on operation principles, electromagnetic performance, design and control aspects. The key features of the machines are summarized. Moreover, the recent development and emerging research directions of the machines are also...
A novel hybrid excitation synchronous generator (HESG) with tangential/radial magnetic path in parallel connection is proposed in this paper. The HESG combines the merits of permanent magnet synchronous generators and electric excitation synchronous generators. The structure characteristics of the HESG are described and the operation principle is introduced. The basic characteristics of the HESG are...
The transverse flux permanent magnet synchronous machine (TFPM) is a novel machine arousing widespread concern in recent years. Achieving high torque density to save energy and rough material and reduce the volume and weight of the machine is the best features of TFPM. However, because of low power factor and complex manufacture technics, the application of TFPM is restricted. The dissertation is...
The calculation method of the no-load and on-load windings voltage of PMSG is proposed based on tooth flux method. This method takes the actual shape of poles and slots and the non-linearity of iron and permanent magnetic material into account. The results of computation and experiments on a PMSG show that tooth flux method is accurate. By use of this method, the values and waveforms of winding voltage...
Nowadays, the most widely used variable speed wind turbine type for units above 1 MW is doubly fed induction generator (DFIG). As the wind power penetration continues to increase, wind turbines are required to remain connected during grid faults to ride-through the faults. This paper gives a control oriented modeling of DFIG wind turbines by using causal ordering graph (COG). The control system consists...
This paper presents the result of the two-dimensional finite element analysis on the effects of rotor pole arc variation and number of teeth per rotor pole with different teeth depths and stator excitation pattern on various performance parameters like cogging torque, developed torque, harmonic torques, torque ripple and phase inductance for an 6/8, three phase flux reversal motor. A novel excitation...
This paper deals with performance analysis of a permanent magnet generator (PMG) considering magnetic losses using d-q axis and equivalent circuit (EC) model based on analytical parameter estimation. Electrical parameters and magnetic power losses are estimated and calculated by analytical methods, respectively. Derived electrical parameters and magnetic losses are employed for the d-q axis and EC...
Dual mechanical port electrical machine (DMPM) is a new breed of energy conversion device and can realize electrical variable transmission in HEV. In this paper, both the equivalent-magnetic-circuit method and FEM are adopted to analyze the electromagnetic coupling of one type permanent magnet DMPM, the uniform field DMPM (UMF-DMPM). The analysis indicates that the electromagnetic coupling between...
This paper presents a novel startup method of a brushless DC motor (BLDCM) without any reverse rotation and vibration. Using short pulse sensing method, the rotor position can be detected dynamically based on the saturation effect of the stator iron. After accelerating the motor to a certain speed at which the back-electromotive force (EMF) method is applied, all the power devices are turned off and...
As the effects of power systempsilas frequency fluctuation and harmonics, errors are unavoidable when using the FFT to analyze the induction motor current signal. In order to saving the problem of frequency leakage and error of the FFT, the polynomial approximation method is employed to obtain simple formulas for frequency correction. This paper is aimed at using the frequency correction to estimate...
According to the character of liquid and gas two-phase flow in the evaporative cooling generator stator bar, the void fraction was calculated and analyzed using universal model. Experiment table of v ray measurement system was erected. Because all the calculation models donpsilat consulted the influence of flux to the drift velocity, the calculated result and the experiment result are not consistent...
Calculation of electromagnetic vibration and noise for disk permanent magnet synchronous machines (DPMSM) by using the finite element method (FEM) is presented in this paper. The pulse measuring system produced by the Danish B&K company for noise and vibration is used to measure a DPMSM in a anechoic chamber. Finally, both calculating and measuring results are analyzed, and the acoustic source...
In this paper, conventional PI controller, sliding mode controller (SMC) and fuzzy logic controller (FLC) for rotor field oriented controlled (RFOC) induction motor drives are studied comparatively. PI is simple but sensitive to parameter variations. SMC provides strong robustness to parameters variations, disturbance rejection and system order reduction. FLC does not need exact system mathematical...
A modified direct torque control (DTC) scheme for surface permanent magnet synchronous machine (SPM) is investigated in this paper, which features in very low flux and torque ripple and almost fixed switching frequency. It is based on the deadbeat control of the flux and torque. Simulation results show that the flux and torque ripples are greatly reduced when compared with those of the basic DTC....
For a V/F controlled induction motor drive system, the instability problem of sustained oscillations has often been experienced in light load state. This paper analyzes the relationship between the oscillations and the fluctuation of reactive currents and then proposes a method to improve the stability of conventional V/F control algorithm. This paper contributes to the solution of this problem based...
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