Background Sawtooth wave buncher is widely used in low-energy ion injection at cyclotron accelerators.Its performance significantly impacts on the intensity of ion beam delivered to experimental terminals.In order to ...Background Sawtooth wave buncher is widely used in low-energy ion injection at cyclotron accelerators.Its performance significantly impacts on the intensity of ion beam delivered to experimental terminals.In order to meet the high-intensity requirement of physical experiments,we upgrade the existing B02 buncher in the axial injection line of the SFC with the dual-model sawtooth wave buncher for low-energy ion injection.Methods We use a three harmonics synthesis method in the dual-sawtooth wave buncher.First,we use three harmonics to generate a low-level sawtooth wave.Second,the low-level wave is amplified by a broadband amplifier to generate high voltage at a single-gap electrode.Third,the electrode is matched to the amplifier by a 1:9 transmission line transformer.Results The new buncher has been installed online since September 2022.Our tested results show that the buncher is capable of being operated at the full-frequency mode and half-frequency mode with the corresponding frequency ranging from 2.75 to 8.0 MHz and 5.5 to 16.0 MHz,respectively.The effective voltage can be up to 2.54 kV and 1.6 kV,respectively.Also,the sawtooth wave buncher works reliably,and a 4.5-8.6 times gain in the beam intensity is achieved.Conclusion By using the three-harmonic synthesis method,a new dual-mode high-voltage sawtooth wave buncher has been built.This sawtooth wave buncher has succeeded in being applied with the high buncher voltage over a wide frequency range with good reliability and stability.This newly-built sawtooth wave buncher significantly increases the ion beam current for low-energy ion injection at the HIRFL-SFC cyclotron.展开更多
This paper proposes a novel approach for generating a multi-scroll chaotic system. Together with the theoretical design and numerical simulations, three different types of attractor are available, governed by construc...This paper proposes a novel approach for generating a multi-scroll chaotic system. Together with the theoretical design and numerical simulations, three different types of attractor are available, governed by constructing triangular wave, sawtooth wave and hysteresis sequence. The presented new multi-scroll chaotic system is different from the classical multi-scroll chaotic Chua system in dimensionless state equations, nonlinear functions and maximum Lyapunov exponents. In addition, the basic dynamical behaviours, including equilibrium points, eigenvalues, eigenvectors, eigenplanes, bifurcation diagrams and Lyapunov exponents, are further investigated. The success of the design is illustrated by both numerical simulations and circuit experiments.展开更多
目前Buck电路输出侧LC滤波器的设计方法为基于电压电流纹波、功率密度与成本的设计,但在可靠性要求较高的应用中,直流变换器寿命为评价直流变换系统性能的关键指标。在当前LC滤波器设计因素的基础上,从可靠性角度提出了一种LC滤波器的...目前Buck电路输出侧LC滤波器的设计方法为基于电压电流纹波、功率密度与成本的设计,但在可靠性要求较高的应用中,直流变换器寿命为评价直流变换系统性能的关键指标。在当前LC滤波器设计因素的基础上,从可靠性角度提出了一种LC滤波器的优化设计方法。首先研究了电感值与电容值对系统中电解电容发热的影响,再结合电解电容寿命模型,进一步分析了不同滤波器参数下的电解电容寿命,并根据电解电容寿命要求,设计了1 k W Buck直流变换器可靠性较高的LC滤波器参数。最后以Matlab仿真平台与1 k W Buck实验平台作为检验手段,对计算结果进行了验证。展开更多
基金provided by Chinese Academy of Sciences,(Y9HIRLL100)National Natural Science Foundation of China,(11975289),Yan Cong.
文摘Background Sawtooth wave buncher is widely used in low-energy ion injection at cyclotron accelerators.Its performance significantly impacts on the intensity of ion beam delivered to experimental terminals.In order to meet the high-intensity requirement of physical experiments,we upgrade the existing B02 buncher in the axial injection line of the SFC with the dual-model sawtooth wave buncher for low-energy ion injection.Methods We use a three harmonics synthesis method in the dual-sawtooth wave buncher.First,we use three harmonics to generate a low-level sawtooth wave.Second,the low-level wave is amplified by a broadband amplifier to generate high voltage at a single-gap electrode.Third,the electrode is matched to the amplifier by a 1:9 transmission line transformer.Results The new buncher has been installed online since September 2022.Our tested results show that the buncher is capable of being operated at the full-frequency mode and half-frequency mode with the corresponding frequency ranging from 2.75 to 8.0 MHz and 5.5 to 16.0 MHz,respectively.The effective voltage can be up to 2.54 kV and 1.6 kV,respectively.Also,the sawtooth wave buncher works reliably,and a 4.5-8.6 times gain in the beam intensity is achieved.Conclusion By using the three-harmonic synthesis method,a new dual-mode high-voltage sawtooth wave buncher has been built.This sawtooth wave buncher has succeeded in being applied with the high buncher voltage over a wide frequency range with good reliability and stability.This newly-built sawtooth wave buncher significantly increases the ion beam current for low-energy ion injection at the HIRFL-SFC cyclotron.
文摘传统方法为了产生多电平电压,往往需要每个H桥单元都有一个独立对应的半周期对称三角载波,且不同载波之间有一个固定的移相角度。而对基于锯齿波的载波移相技术研究的较少。为此,提出了一种基于锯齿波的载波移相脉冲宽度调制(pulse width modulation,PWM)技术。与传统方法相比,在该方法中,所有功率单元都使用同一个载波作为时间参考,并使用非对称PWM发生器来产生传统的对称的载波移相PWM波形。采用数字信号处理器(digital signal processor,DSP)芯片TMS320F2812对一个5单元11电平进行载波移相试验,采用所提的锯齿载波移相PWM技术实现方法,仅通过事件管理器就可以对5单元变换器提供开关脉冲。试验结果验证了所提方法的正确性和有效性。
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60572073 and 60871025)the Natural Science Foundation of Guangdong Province,China (Grant Nos 8151009001000060,5001818 and 8351009001000002)
文摘This paper proposes a novel approach for generating a multi-scroll chaotic system. Together with the theoretical design and numerical simulations, three different types of attractor are available, governed by constructing triangular wave, sawtooth wave and hysteresis sequence. The presented new multi-scroll chaotic system is different from the classical multi-scroll chaotic Chua system in dimensionless state equations, nonlinear functions and maximum Lyapunov exponents. In addition, the basic dynamical behaviours, including equilibrium points, eigenvalues, eigenvectors, eigenplanes, bifurcation diagrams and Lyapunov exponents, are further investigated. The success of the design is illustrated by both numerical simulations and circuit experiments.
文摘目前Buck电路输出侧LC滤波器的设计方法为基于电压电流纹波、功率密度与成本的设计,但在可靠性要求较高的应用中,直流变换器寿命为评价直流变换系统性能的关键指标。在当前LC滤波器设计因素的基础上,从可靠性角度提出了一种LC滤波器的优化设计方法。首先研究了电感值与电容值对系统中电解电容发热的影响,再结合电解电容寿命模型,进一步分析了不同滤波器参数下的电解电容寿命,并根据电解电容寿命要求,设计了1 k W Buck直流变换器可靠性较高的LC滤波器参数。最后以Matlab仿真平台与1 k W Buck实验平台作为检验手段,对计算结果进行了验证。
