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IEEE Energy Conversion Congress and Exposition

作者： Dongdong Yang Changsong Chen Shanxu Duan Jiuqing Cai State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China

ISBN: (纸本)9781479957774

In order to limit the resonant current, the LLC resonant converter usually starts up with a frequency which is much higher than the resonant frequency. However, if the start-up frequency is too high, the build-up time of the output voltage will be very long. Moreover, the start-up frequency is also limited by the hardware condition such as drive circuit. In this paper, the start-up process for the LLC resonant converter is investigated based on state-plane method. The expression of start-up current in the resonant tank is derived. The relationship between start-up current and start-up frequency is discussed. According to the analysis, some rules are given about how to select the start-up frequency. An improved start-up method is proposed to limit the start-up current at a low start-up frequency. Experimental results are presented to verify the conclusions.

关键词： Resonant frequency Trajectory Stress Time-frequency analysis Switches Capacitors Inductors

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Neural Network Prediction of Disruptions Caused by Locked Modes on J-TEXT Tokamak

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Plasma Science and technology 2013年第11期15卷 1154-1159页

作者：丁永华金雪松陈真真庄革 State Key Laboratory of Advanced Electromagnetic Engineering and Technology College of Electrical and Electronic Engineering Huazhong University of Science and Technology

Prediction of disruptions caused by locked modes using the Back-Propagation （BP） neural network is completed on J-TEXT tokamak. The network, which is based on the BP neural network, uses Mirnov coils and locked mode coils signals as input data, and outputs a signal including information of prediction of locked mode. The rate of successful prediction of locked modes is more than 90%. For intrinsic locked mode disruptions, the network can give a prewarning signal about 1 ms ahead of the locking-time. For the disruption caused by resonant magnetic perturbation （RMPs） locked modes, the network can give a prewarning signal about 10 ms ahead of the locking-time.

关键词： disruption locked mode BP neural network prediction

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Optimal idling speed control of direct-drive electric vehicle launch in consideration of drive comfort

Optimal idling speed control of direct-drive electric vehicl...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Ping Xiong Chenglin Gu State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan P.R. China

ISBN: (纸本)9781479951635

By using clutch for replacing rigid connection with a flexible one between hub and wheel-motor, a novel solution for in-wheel drive is proposed with the possibilities of `no-load starting and variable-idle clutching' together in this paper. It is then important to choose suitable idling speed of wheel motor for assuring drive comfort from a standing start in direct-drive electric vehicle. Based on the actual load torque, the control strategy of optimal idling speed is discussed in the aim of enhancing drive comfort and reducing electromagnetic impulsion.

关键词： Vehicles Torque DC motors Mathematical model Acceleration Couplings Equations

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Optimal design of axial flux switched reluctance motor for electric vehicle application

Optimal design of axial flux switched reluctance motor for e...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Jimin Ma Ronghai Qu Jian Li State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China School of Electrical & Electronic Engineering Hubei University of Technology

ISBN: (纸本)9781479951635

Design of wheel motors must conform to the diameter restriction due to cage of a wheel rim and allow the achievement of high torque density. In addition, these motors should be rugged and insensitive to vibration. Therefore, an axial flux switched motor (AFSRM) machine with double stator and one rotor structure is investigated. In general, AFSRM have simple construction; however, one of the major problems is torque ripple which will cause speed fluctuation and acoustic noise. View of this, the skewed stator segments by a specific degree respectively to the rotor with asymmetric inductance property is applied to reduce the torque drop in the phase commutation area. The proposed method is analyzed by magnetic equivalent circuit approach (MECA) and finite element analysis (FEA) method. Through the parameter study, torque ripple reduction in proposed machine is significant in comparison with the one of conventional non-skewed stator machine.

关键词： Stator windings Rotors Torque Inductance Magnetic flux Lead

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Analytical calculation of d- and q-axis synchronous reactances of homopolar inductor alternator

Analytical calculation of d- and q-axis synchronous reactanc...

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electromagnetic Launch technology

作者： Zhenxiu Lou Yigang He Yuan Cheng Caiyong Ye Kexun Yu Hefei University of Technology Hefei China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

In this paper, the d- and q-axis synchronous reactances of homopolar inductor alternator (HIA) are calculated. First, an approximate 2D model of HIA is developed and its relative air-gap permeance function is described. The harmonic amplitudes of the per-unit quantity of relative air-gap permeance function are determined by 2D finite element analysis (FEA). Then, the analytical expressions for the synchronous reactances in the direct-axis (d-axis) and quadrature-axis (q-axis) are derived from magnetomotive force (MMF)-relative air-gap permeance function theory, including armature reaction reactance and armature leakage reactance. Finally, theoretical results are compared with the simulation and experimental results.

关键词： Air gaps Rotors Windings Armature Stator cores Harmonic analysis

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Stable sensorless V/f and cosφ =1 control for permanent magnet synchronous motor drives

Stable sensorless V/f and cosφ =1 control for permanent mag...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Kai Yang Xingxing Yang Hongqin Xie Yang Liu Yingli Zhang Xubiao Wei State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan R. P. China

ISBN: (纸本)9781479951635

This paper proposes a novel control structure for scalar sensorless V/f controlled permanent magnetic synchronous motor (PMSM) drives with two feedback corrections in the new created d v q v reference frame: i) a speed stabilizing correction using input active power variation to moderate the stator applied frequency to ensure the stable operation, ii) a voltage amplitude correction employing the PI regulation of q v -axis current, that is the reactive current component, eventually realizes cosφ =1. The addition of PI regulator which also influences the stability of system is explored. Moreover, based on a basic V/f control, the scheme can greatly simplify the calculation and enhance insensitivity to the motor parameters. The proposed solution is simple, non-oscillatory and of good robustness. The simulation and experiments are carried out to prove the performance and validity.

关键词： Rotors Stators Voltage control Vectors Torque Stability analysis Steady-state

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Study on the dynamic simulation of prime mover of a turbine-generator

Study on the dynamic simulation of prime mover of a turbine-...

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IEEE PES Asia-Pacific Power and Energy engineering Conference (APPEEC)

作者： Dexian Yang Fengwei Tian State Key Laboratory of Advanced Electromagnetic Engineering Huazhong University of Science and Technology (HUST) Wuhan Hubei Province China

Aiming at the simulation for the prime mover supplied by thyristor, the principle and the fundamental methods to dynamically simulate the self-balancing characteristics of a turbine are studied in this paper. A new scheme is presented to simulate the characteristics of the prime mover when the generator simulator operates in various conditions. Nonlinear control components are adopted to solve long-existing problem on the simulation of the prime mover. Test results verify that the performance of the proposed scheme has its superiority.

关键词： Power system dynamics Mathematical model Torque Turbines Generators Load modeling Equations

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Reconsideration of Loop Gain Measurement of DC/DC Converters

Reconsideration of Loop Gain Measurement of DC/DC Converters

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IEEE Energy Conversion Congress and Exposition

作者： Chun Xiong Xinbo Ruan Peilin Chen Xuehua Wang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan P. R. China

ISBN: (纸本)9781479957774

There are mainly two existing loop gain measurement methods, which are the modulating signal perturbation method (MSPM) and the pulse-width signal perturbation method (PSPM). This paper points out that there are differences between these methods, and the loop gain measured by the PSPM can be more easily used in the guidance of the controller design. Since the circuit implementation of the PSPM is not easy, the additional PWM modulation method (APMM) and the sample-and-hold method (SHM) with uncomplicated circuits are proposed. The experiment results verify the correctness of the theoretical analysis and the proposed loop gain measurement methods.

关键词： Pulse width modulation Gain measurement Transfer functions Switches Frequency modulation Cutoff frequency

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Short-term Wind Power Completing and Forecasting Based on Rough Set and BP Neural Network

Short-term Wind Power Completing and Forecasting Based on Ro...

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2014 International Conference on Power and Energy(ICPE 2014)

作者： Y.F.Zeng B.H.Zhang J.L.Wu B.J.Jin M.Li S.Zhao K.Wang D.Zeng State Key Laboratory of Advanced Electromagnetic Engineering and Technology of Huazhong University of Science and Technology China Electric Power Research Institute(Nanjing)

When we use BP neural network to forecast the wind power, the selection of input variables is the key issue that affects the forecasting results. This paper proposes a method using rough set theory to solve this problem. On the basis of considering the correlation of the wind turbines, we use the Rough-Set analysis methods extract turbines which are strong associated, then use the wind power data of them as the partial inputs of BP neural network and build the RS-BP model(Neural network based on Rough-Set). For the case of wind power data missing, we use the RS-BP to complete the missing data. Then, we use the completed wind power data to forecast the wind power data. This method can select the inputs of neural network reasonably and has the better prediction accuracy. The numerical example shows that this method is effective and feasible.

关键词： Rough-Set BP Neural Network Wind Power Forecasting Correlation

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Stability analysis of cascade AC system based on three-phase voltage source PWM rectifier

Stability analysis of cascade AC system based on three-phase...

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International Electronics and Application Conference and Exposition (PEAC)

作者： Hui Yu Xinbo Ruan Xuehua Wang Hanzhi Zhang Yu Teng State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan P. R. China

ISBN: (纸本)9781479967698

In cascade AC systems, the impedance interaction between the source module and the load module may cause overall system instability. The generalized Nyquist stability criterion can be applied to characterize the stability of cascade three-phase AC systems. But it is usually very complicated and cannot directly reveal effective control strategy to alleviate the interaction problem. Based on three-phase voltage source PWM rectifier, this paper proposes a simplified stability criterion for three-phase AC systems. An input impedance regulator design method is introduced to alleviate the interaction problem. Finally, a 20kW prototype is built and tested. The experimental results confirm the proposed stability criterion and the input impedance regulator design method.

关键词： Impedance Stability criteria Regulators Power system stability Pulse width modulation Rectifiers

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