This paper presents a new approach for modeling of the conducted electromagnetic interference(EMI) prediction for widely used converter systems.Coupling paths and mechanism of differential mode(DM) interference and co...This paper presents a new approach for modeling of the conducted electromagnetic interference(EMI) prediction for widely used converter systems.Coupling paths and mechanism of differential mode(DM) interference and common mode(CM) interference have been analyzed.Models to predict the high-frequency noise of PWM converter system are created.A direct calculation method in frequency domain is proposed for the deduction of frequency spectrum.A method is given for obtaining the parasitic parameters and topological structure of the model.An experimental investigation of the conducted emission from an actual high-power rectifier system is described.The validity of the models is confirmed by comparison to laboratory measurements.展开更多
The ADS （Accelerator Driven subcritical System） driver linac in China is designed to run in CW （Continuous Wave） mode with 10 mA designed beam current. In this scenario, the beam-induced parasitic modes in the ADS...The ADS （Accelerator Driven subcritical System） driver linac in China is designed to run in CW （Continuous Wave） mode with 10 mA designed beam current. In this scenario, the beam-induced parasitic modes in the ADS driver linac may make the beam unstable or deteriorate the beam performance. To evaluate the parasitic mode effect on the beam dynamics systematically, simulation studies using the ROOT-based numerical code SMD have been conducted. The longitudinal beam instability induced by the HOMs （High Order Modes） and SOMs （Same Order Modes） has little effect on the longitudinal beam performance for the current ADS driver linac design based on the 10 MeV/325 MHz injector I from previous studies. Here the transverse parasitic mode （i.e., dipole HOM） effect on the transverse beam performance at the ADS driver linac exit is investigated. To more reasonably quantify the dipole mode effect, the multi-bunch effective emittance is introduced in this paper.展开更多
For the accelerator driven subcritical system （ADS） main linac in China, two families of superconducting elliptical radio frequency （RF） cavities will be used to accelerate the proton beam from 180 MeV to 1.5 GeV....For the accelerator driven subcritical system （ADS） main linac in China, two families of superconducting elliptical radio frequency （RF） cavities will be used to accelerate the proton beam from 180 MeV to 1.5 GeV. When the proton beam traverses in the RF cavity, the excited parasitic modes, like high order modes （HOMs） and same order modes （SOMs）, may drive the beam to become unstable and increase the cryogenic load, thus putting a limitation on the normal operation of the accelerator. In this paper, by using a numerical code SMD based on the ROOT environment, the effects of longitudinal parasitic modes on the beam dynamics for the ADS driving linac in China have been investigated systematically, while parasitic modes which increase cryogenic loss have not been included in this paper. Some conclusions concerning the beam energy ranging from 180 MeV to 1.5 GeV have been obtained.展开更多
高压串联谐振变换器广泛应用于电容器充电、静电除尘等系统中。然而,高压变压器寄生电容的存在,使得客观上并不存在理想的高压串联谐振变换器。定量分析了高压高频变压器的寄生电容对工作于断续谐振电流模式(discontinuous current mode...高压串联谐振变换器广泛应用于电容器充电、静电除尘等系统中。然而,高压变压器寄生电容的存在,使得客观上并不存在理想的高压串联谐振变换器。定量分析了高压高频变压器的寄生电容对工作于断续谐振电流模式(discontinuous current mode,DCM)的串联谐振变换器特性的影响,这些特性包括临界断续谐振频率、归一化输出电流和软开关。当考虑高压变压器寄生电容后,串联谐振变换器实际上已经演变为LCC串并联谐振变换器。通过对DCMLCC谐振变换器在不同工作阶段的数学分析、推导和归一化处理,得到了具有封闭形式的电路特性的表达式。通过分析发现,随着等效电压增益的增加,DCM LCC谐振变换器的正向和反向谐振过程均由两元件谐振向三元件谐振过程转变,临界断续频率升高。以图形曲线的方式给出了量化的分析结果。通过比较两类典型的控制方法可知,第二类典型控制方法具有更高的电流输出能力和能量传输效率,是一种优化的控制方法。所得分析结果可为工作于断续谐振电流模式的高压串联谐振变换器的设计提供参考,特别对电容充电和静电除尘电源具有工程应用价值。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50977063)Key Science and Technology Supporting Project of Tianjin (Grant No. 09ZCKFGX01800)
文摘This paper presents a new approach for modeling of the conducted electromagnetic interference(EMI) prediction for widely used converter systems.Coupling paths and mechanism of differential mode(DM) interference and common mode(CM) interference have been analyzed.Models to predict the high-frequency noise of PWM converter system are created.A direct calculation method in frequency domain is proposed for the deduction of frequency spectrum.A method is given for obtaining the parasitic parameters and topological structure of the model.An experimental investigation of the conducted emission from an actual high-power rectifier system is described.The validity of the models is confirmed by comparison to laboratory measurements.
文摘The ADS （Accelerator Driven subcritical System） driver linac in China is designed to run in CW （Continuous Wave） mode with 10 mA designed beam current. In this scenario, the beam-induced parasitic modes in the ADS driver linac may make the beam unstable or deteriorate the beam performance. To evaluate the parasitic mode effect on the beam dynamics systematically, simulation studies using the ROOT-based numerical code SMD have been conducted. The longitudinal beam instability induced by the HOMs （High Order Modes） and SOMs （Same Order Modes） has little effect on the longitudinal beam performance for the current ADS driver linac design based on the 10 MeV/325 MHz injector I from previous studies. Here the transverse parasitic mode （i.e., dipole HOM） effect on the transverse beam performance at the ADS driver linac exit is investigated. To more reasonably quantify the dipole mode effect, the multi-bunch effective emittance is introduced in this paper.
文摘For the accelerator driven subcritical system （ADS） main linac in China, two families of superconducting elliptical radio frequency （RF） cavities will be used to accelerate the proton beam from 180 MeV to 1.5 GeV. When the proton beam traverses in the RF cavity, the excited parasitic modes, like high order modes （HOMs） and same order modes （SOMs）, may drive the beam to become unstable and increase the cryogenic load, thus putting a limitation on the normal operation of the accelerator. In this paper, by using a numerical code SMD based on the ROOT environment, the effects of longitudinal parasitic modes on the beam dynamics for the ADS driving linac in China have been investigated systematically, while parasitic modes which increase cryogenic loss have not been included in this paper. Some conclusions concerning the beam energy ranging from 180 MeV to 1.5 GeV have been obtained.
文摘高压串联谐振变换器广泛应用于电容器充电、静电除尘等系统中。然而,高压变压器寄生电容的存在,使得客观上并不存在理想的高压串联谐振变换器。定量分析了高压高频变压器的寄生电容对工作于断续谐振电流模式(discontinuous current mode,DCM)的串联谐振变换器特性的影响,这些特性包括临界断续谐振频率、归一化输出电流和软开关。当考虑高压变压器寄生电容后,串联谐振变换器实际上已经演变为LCC串并联谐振变换器。通过对DCMLCC谐振变换器在不同工作阶段的数学分析、推导和归一化处理,得到了具有封闭形式的电路特性的表达式。通过分析发现,随着等效电压增益的增加,DCM LCC谐振变换器的正向和反向谐振过程均由两元件谐振向三元件谐振过程转变,临界断续频率升高。以图形曲线的方式给出了量化的分析结果。通过比较两类典型的控制方法可知,第二类典型控制方法具有更高的电流输出能力和能量传输效率,是一种优化的控制方法。所得分析结果可为工作于断续谐振电流模式的高压串联谐振变换器的设计提供参考,特别对电容充电和静电除尘电源具有工程应用价值。
