Application of wavelet-based active power filter in accelerator magnet power supply

Since modern accelerators demand excellent stability to magnet power supply(PS), it is necessary to decrease harmonic currents passing magnets. Aiming at depressing the rappel current from the PS in the Beijing electron-positron collider, a wavelet-based active power filter(APF) is proposed in this paper. An APF is an effective device to improve the quality of currents. As a countermeasure to these harmonic currents, the APF circuit generates a harmonic current, countervailing harmonic current from PS. An active power filter based on wavelet transformation is proposed. Discrete wavelet transformation is used to analyze the harmonic components in the supply current, and an active power filter circuit works according to the analysis results. Our simulation and experiment results are given to prove the effect of the APF.     

Application of wavelet-based active magnet power supply filter in accelerator

Since modern accelerators demand excellent stability to magnet power supply （PS）, it is necessary to decrease harmonic currents passing magnets. Aiming at depressing the rappel current from the PS in the Beijing electron-positron collider Ⅱ, a wavelet-based active power filter （APF） is proposed in this paper. An APF is an effective device to improve the quality of currents. As a countermeasure to these harmonic currents, the APF circuit generates a harmonic current, countervailing harmonic current from PS. An active power filter based on wavelet transformation is proposed. Discrete wavelet transformation is used to analyze the harmonic components in the supply current, and an active power filter circuit works according to the analysis results. Our simulation and experiment results are given to prove the effect of the APF.     

14T核磁共振成像超导磁体电源拓扑设计及纹波抑制

根据14T 核磁共振成像(MRI)大电感超导体磁体(电感307H、连接阻抗2mΩ)负载纹波的需求(低压为3V、电流为1500A、电流纹波小于1ppm)，基于常见拓扑结构出现的问题，提出了一种适用于这种大电感超导磁体运行电源的拓扑结构。此拓扑结构采用多级处理、无源滤波和有源滤波相结合的思想来设计。介绍了电源的输入级、中间变换级及输出级三个部分的拓扑，并阐述了各部分拓扑设计对负载电流纹波抑制的作用。通过 Matlab 仿真分析，验证了拓扑设计的合理性。     

指数型径向阻抗变换器功率传输效率的优化设计

利用解析方法和电路模拟方法研究了阻抗变换器功率传输效率的优化设计。电路计算中,采用了脉冲上升沿等效的正半周正弦波作为输入波形的假设,并忽略了水介质能量损失的影响。首先对比了线性、饱和型变化和陡变型变化3种典型阻抗的功率和能量传输效率,分析讨论了影响指数型阻抗变换器功率传输效率的关键影响因素,并得到了功率传输效率最大化的中间参数和符合系数的参数范围。讨论了实际设计中应注意的绝缘安全系数的结构设计、杂散参数对阻抗计算的影响、水介质能量损失等问题。     

指数型径向阻抗变换器功率传输效率的优化设计

 利用解析方法和电路模拟方法研究了阻抗变换器功率传输效率的优化设计。电路计算中,采用了脉冲上升沿等效的正半周正弦波作为输入波形的假设,并忽略了水介质能量损失的影响。首先对比了线性、饱和型变化和陡变型变化3种典型阻抗的功率和能量传输效率,分析讨论了影响指数型阻抗变换器功率传输效率的关键影响因素,并得到了功率传输效率最大化的中间参数和符合系数的参数范围。讨论了实际设计中应注意的绝缘安全系数的结构设计、杂散参数对阻抗计算的影响、水介质能量损失等问题。     

Control application of a superconducting magnet power supply based on EPICS

The superconducting quadrupole magnets （SCQs） are powered by 16 power supplies in the inter- action region of the BEPC Ⅱ. The control application of these power supplies must be interlocked with the quench protection system to protect the superconducting magnet and relevant devices. This paper describes the development procedures of this control application using EPICS and the operating result with the quench protection system on-site.     

合肥光源小功率直流磁铁电源的研究

电子加速器通过对电磁场精细调整使得电子束按理想轨道运行,要求励磁电源电流精度高、稳定度高、纹波小、抗干扰能力强。介绍了合肥光源小功率直流磁铁电源系统结构和控制器系统及控制算法,并进行了仿真和实验研究。实验测得,在负载电感1 mH、等效串联电阻0.049 ,输出电流25 A下电流纹波率2.12,40 min电流稳定度6.6,电流分辨率0.01。这表明：所设计的主电路和控制器系统适用于小功率直流磁铁电源的实验研究。     

Control application of a superconducting magnet power supply based on EPICS

The superconducting quadrupole magnets(SCQs)are powered by 16 power supplies in the inter-action region of the BEPC Ⅱ.The control application of these power supplies must be interlocked with the quench protection system to protect the superconducting magnet and relevant devices.This paper describes the development procedures of this control application using EPICS and the operating result with the quench protection system on-site.     

高磁场磁共振超导磁体电源的拓扑设计与分析

针对高磁场磁共振大孔径人体成像系统中超导磁体电源在励磁时向磁体充能、退磁时把能量“逆变” 回电网的设计要求,比较了两种能量回馈型的拓扑结构。通过 Matlab 仿真分析,验证了拟采用的拓扑结构的合 理性。      

串联谐振充电电源分析及设计

 推导了串联谐振充电电源不同工作模式下的电流、电压计算公式，给出了计算不同周期电流、电压值的递推公式；应用递推公式说明了这种电源的脉动恒流充电特性；给出了负载电容不完全放电情况下电源参数的计算方法。在负载电容完全放电的情况下，电源的平均输出功率为最大输出功率的一半，在负载电容电压基本维持恒定的情况下，电源平均输出功率与最大输出功率相等；最后给出了一台为Tesla型加速器初级储能电容充电的谐振电源的设计实例，电源的实测结果和计算结果一致，在100Hz重复频率下运行稳定可靠。