动态特性是变换器以及能源系统的一个重要的指标。为提高双向全桥(dual active bridge,DAB)DC-DC变换器对负载突变的动态响应速度,该文以单相移控制为例,基于直接功率控制思想,提出一种负载电流前馈控制方法,并对该方法进行了详细的分...动态特性是变换器以及能源系统的一个重要的指标。为提高双向全桥(dual active bridge,DAB)DC-DC变换器对负载突变的动态响应速度,该文以单相移控制为例,基于直接功率控制思想,提出一种负载电流前馈控制方法,并对该方法进行了详细的分析。该方法不需要电感等电路参数参与控制,这增加了控制方法的兼容性和可移植性。最后,硬件在环实验平台和基于TMS320F28335的实物实验平台上,对所提出的电流前馈控制方法和传统单相移控制算法进行对比验证。实验结果表明:该电流前馈控制方法在负载突变时,能获得快速的动态响应,输出电压基本保持不变,且对电感参数无依赖性。展开更多
考虑到牵引动车段(所)与地方220/110 kV电源距离较远时,电源接入投资较大,提出一种由市电10 kV电源供电的单相变流器控制的YNvd平衡变压器牵引供电方案。首先考虑到平衡变压器的供电特点,采用交-直-交单相变流器与平衡变压器两相侧并联...考虑到牵引动车段(所)与地方220/110 kV电源距离较远时,电源接入投资较大,提出一种由市电10 kV电源供电的单相变流器控制的YNvd平衡变压器牵引供电方案。首先考虑到平衡变压器的供电特点,采用交-直-交单相变流器与平衡变压器两相侧并联;然后通过两相电压互差90°的瞬时功率检测方法得出补偿指令电流,控制变流器的输出,从而使平衡变压器的两相侧平衡,有效抑制了三相侧的谐波和负序分量,可满足电网公共连接点(point of common coupling,PCC)对电能质量的要求。最后,应用Matlab/Simulink软件搭建系统仿真模型,对系统在空载、重载爬坡、单臂有车、双臂有车等不同负荷工况下PCC点的三相电压、三相电流不平衡度进行仿真计算,仿真结果验证了所提方案经济合理、技术可行,并给出对10 kV市电最小短路容量的要求。展开更多
Numerical simulation of transient mass transfer to a single dropcontrolled by the internal resistance or by the resistance in bothphases was mathematically formulated and simulated in aboundary-fitted orthogonal coord...Numerical simulation of transient mass transfer to a single dropcontrolled by the internal resistance or by the resistance in bothphases was mathematically formulated and simulated in aboundary-fitted orthogonal coordinate system. The simulated resultson the transient mass transfer dominated by the internal resistanceare in good agreement with the Newman and Kronig-Brink models fordrops with low Reynolds number. When the drop Reynolds number is upto 200, the mass transfer coefficient from numerical simulation isvery low as compared with The Handlos-Baron model.展开更多
A method of feedforward compensation for electromotive force(EMF) in the single-phase permanent magnet linear generation system and a research in the performance of the single-phase PMLG system are presented.A general...A method of feedforward compensation for electromotive force(EMF) in the single-phase permanent magnet linear generation system and a research in the performance of the single-phase PMLG system are presented.A general mathematical model for the single-phase permanet magnet linear generator(PMLG) system is established and the current loop,voltage loop and the feedforward control are studied based on it for the control system.Then this paper analyses the transfer function of the power system,optimizes current loop and voltage loop parameters by engineering algorithm,and calculates the optimal control parameters.An EMF feedforward compensation method is developed to optimize the control system which improves dynamic performance of the power system but does not affect the steady-state performance.The result of this research verifies the correctness and rationality of the design for the control system.展开更多
A very simpJe theoretical scheme is proposed to implement two-and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. I...A very simpJe theoretical scheme is proposed to implement two-and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. In the presented protocol, the quantum information is encoded on the stable ground states of the atoms （as the controlling qubits） and the zero- and one-photon Fock states of cavity-field （as the target qubit）. Under the influence of the atomic spontaneous emission, the decay of the cavity-mode, and deviation of the coupling strength, the three-qubit controlled- phase gate may have a comparatively high fidelity. The experimental feasibility of controlled-phase gate and the ease that is extended to realize N-qubit controlled-phase gate are also discussed.展开更多
文摘动态特性是变换器以及能源系统的一个重要的指标。为提高双向全桥(dual active bridge,DAB)DC-DC变换器对负载突变的动态响应速度,该文以单相移控制为例,基于直接功率控制思想,提出一种负载电流前馈控制方法,并对该方法进行了详细的分析。该方法不需要电感等电路参数参与控制,这增加了控制方法的兼容性和可移植性。最后,硬件在环实验平台和基于TMS320F28335的实物实验平台上,对所提出的电流前馈控制方法和传统单相移控制算法进行对比验证。实验结果表明:该电流前馈控制方法在负载突变时,能获得快速的动态响应,输出电压基本保持不变,且对电感参数无依赖性。
文摘考虑到牵引动车段(所)与地方220/110 kV电源距离较远时,电源接入投资较大,提出一种由市电10 kV电源供电的单相变流器控制的YNvd平衡变压器牵引供电方案。首先考虑到平衡变压器的供电特点,采用交-直-交单相变流器与平衡变压器两相侧并联;然后通过两相电压互差90°的瞬时功率检测方法得出补偿指令电流,控制变流器的输出,从而使平衡变压器的两相侧平衡,有效抑制了三相侧的谐波和负序分量,可满足电网公共连接点(point of common coupling,PCC)对电能质量的要求。最后,应用Matlab/Simulink软件搭建系统仿真模型,对系统在空载、重载爬坡、单臂有车、双臂有车等不同负荷工况下PCC点的三相电压、三相电流不平衡度进行仿真计算,仿真结果验证了所提方案经济合理、技术可行,并给出对10 kV市电最小短路容量的要求。
基金Supported by the National Natural Science Foundation of China (No. 29792074, No. 29836130} and SINOPEC.
文摘Numerical simulation of transient mass transfer to a single dropcontrolled by the internal resistance or by the resistance in bothphases was mathematically formulated and simulated in aboundary-fitted orthogonal coordinate system. The simulated resultson the transient mass transfer dominated by the internal resistanceare in good agreement with the Newman and Kronig-Brink models fordrops with low Reynolds number. When the drop Reynolds number is upto 200, the mass transfer coefficient from numerical simulation isvery low as compared with The Handlos-Baron model.
基金Supported by the National High Technology Research and Development Program of China(No.2006AA05Z231)the National Natural Science Foundation of China(No.51177025)
文摘A method of feedforward compensation for electromotive force(EMF) in the single-phase permanent magnet linear generation system and a research in the performance of the single-phase PMLG system are presented.A general mathematical model for the single-phase permanet magnet linear generator(PMLG) system is established and the current loop,voltage loop and the feedforward control are studied based on it for the control system.Then this paper analyses the transfer function of the power system,optimizes current loop and voltage loop parameters by engineering algorithm,and calculates the optimal control parameters.An EMF feedforward compensation method is developed to optimize the control system which improves dynamic performance of the power system but does not affect the steady-state performance.The result of this research verifies the correctness and rationality of the design for the control system.
基金Supported by Key Scientific Research Fund of Hunan Provincial Education Department of China under Grant No. 09A013Natural Science Foundation of Hunan Province of China under Grant No. 08J J3001Normal and Science Foundation of Hengyang Normal University of China under Grant No. 09A28
文摘A very simpJe theoretical scheme is proposed to implement two-and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. In the presented protocol, the quantum information is encoded on the stable ground states of the atoms （as the controlling qubits） and the zero- and one-photon Fock states of cavity-field （as the target qubit）. Under the influence of the atomic spontaneous emission, the decay of the cavity-mode, and deviation of the coupling strength, the three-qubit controlled- phase gate may have a comparatively high fidelity. The experimental feasibility of controlled-phase gate and the ease that is extended to realize N-qubit controlled-phase gate are also discussed.
