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消失场的能量关系及WKBJ分析法 被引量:5
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作者 黄志洵 《中国传媒大学学报(自然科学版)》 2011年第3期1-17,共17页
对于电磁波在均匀媒质中的传播,至少有3种不同机制会使场阻抗产生电抗性分量——有耗媒质中的平面波、电离气体中的平面波、导波模式;因而使人们关注微波在有耗媒质(例如半导体)和等离子体中的传播,关注电磁波在截止频率以下的波导中的... 对于电磁波在均匀媒质中的传播,至少有3种不同机制会使场阻抗产生电抗性分量——有耗媒质中的平面波、电离气体中的平面波、导波模式;因而使人们关注微波在有耗媒质(例如半导体)和等离子体中的传播,关注电磁波在截止频率以下的波导中的情况。在上述情形中,方向相反的两个贮能场会因相互作用从而产生一个净功率流,亦即纯消失态的入射场和反射场会产生能量流,即使分开来看各个场均未携带有功功率。本文从不同角度论述了这一概念。以光纤为对象讨论了光的射线理论及二者的结合运用,这时其效果将是最好。指出了区分光纤中的漏模和折射波辐射的方法。E.Schrdinger对波动力学作出了最大贡献;Schrdinger方程(SE)不仅用在微观粒子分析中,也能处理宏观科学问题,例如光纤。数学物理问题中的许多微分方程归结为ξ2ψ″+p2ψ=0,本文论述了由Wentzel、Kramers、Bril-louim、Jeffreys提出的近似方法在缓变折射率光纤分析中的应用,方法适用于SE的求解。 展开更多
关键词 消失场 电抗性系统 光纤中的漏模 Schrdinger方程 WKBJ法
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Predictive current control system of PMSM based on LADRC 被引量:2
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作者 Wang Xiaopeng Zhao Jun +1 位作者 Wang Bohui Li Baomin 《Journal of Southeast University(English Edition)》 EI CAS 2022年第3期227-234,共8页
For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting ... For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting in the inability to balance the system robustness and dynamic performance.A PMSM optimal control strategy combining linear active disturbance rejection control(LADRC)and two-vector MPCC(TV-MPCC)is proposed.Firstly,a mathematical model of a PMSM is presented,and the PMSM TV-MPCC model is developed in the synchronous rotation coordinate system.Secondly,a first-order LADRC controller composed of a linear extended state observer and linear state error feedback is designed to reduce the complexity of parameter tuning while linearly simplifying the traditional active disturbance rejection control(ADRC)structure.Finally,the conventional PI speed regulator in the motor speed control system is replaced by the designed LADRC controller.The simulation results show that the speed control system using LADRC can effectively deal with the changes in motor parameters and has better robustness and dynamic performance than PI control and similar methods.The system has a fast motor speed response,small overshoot,strong anti-interference,and no steady-state error,and the total harmonic distortion is reduced. 展开更多
关键词 permanent magnet synchronous motor(PMSM) two-vector model predictive current control linear active disturbance rejection control speed control system
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Analysis on the Fast Excitation System of Composite Magnetic Controllable Reactor
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作者 Cuizhi WANG 《International English Education Research》 2014年第10期40-42,共3页
The fast excitation system of a composite magnetic controllable reactor is introduced. In this excitation system, a bidirectional function (i.e. fast forward excitation and backward forcible demagnetization) is avai... The fast excitation system of a composite magnetic controllable reactor is introduced. In this excitation system, a bidirectional function (i.e. fast forward excitation and backward forcible demagnetization) is available, which can significantly improve the response speed, performances, and application scope of magnetic controllable reactor. 展开更多
关键词 COMPOSITE FAST EXCITATION Magnetic Control REACTOR
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Application of linear active disturbance rejection control for photoelectric tracking system
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作者 王婉婷 Guo Jin +1 位作者 Jiang Zhenhua Wang Tingfeng 《High Technology Letters》 EI CAS 2017年第3期315-321,共7页
Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed contr... Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed controller is designed by a transfer function model,which is obtained by adaptive differential evolution. Model error,friction and nonlinear factor existing in position loop are treated as ‘disturbance',which is estimated and compensated by generalized proportional integral( GPI)observer. Comparative results are provided to demonstrate the remarkable performance of the proposed method. It turns out that the proposed scheme is successful and has superior features,such as quick dynamic response,low overshoot and high tracking precision. Furthermore,with the proposed method,friction is suppressed effectively. 展开更多
关键词 photoelectric tracking system linear active disturbance rejection control(LADRC) generalized proportional integral observer adaptive differential evolution
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