A high-voltage power supply of the diagnostic neutral beam injector of the Alcator-Cmod tokamak

A diagnostic neutral beam injector for ensuring the active spectroscopic diagnostics of plasma parameters in the Alcator-Cmod tokamak (Massachusetts Institute of Technology (MIT), Boston, United States) is designed and manufactured at the Institute of Nuclear Physics (Novosibirsk). The energy of fast atoms of the diagnostic injector is determined by the output voltage level of the high-voltage power supply and can vary from 20 to 55 keV. The ion source of the diagnostic neutral beam injector generates proton beams with an equivalent current of up to 7 A. The accelerated protons after the neutralization on a gas target produce streams of neutral particles—fast atoms with an equivalent current of up to 4 A. The diagnostic neutral beam injector is capable of producing 100% energy-modulated fast hydrogen atomic beams, and this is ensured by operation of the high-voltage power supply under the corresponding law. The high-voltage power supply is based on modules consisting of high-frequency transformers and diode rectifiers placed in a sealed tank filled with insulating gas SF₆. The output voltage is smoothly regulated from 20 to 55 kV by IGBT inverters with a pulse-width control energizing the primary windings of the step-up high-frequency transformers. The high-voltage power supply allows the multiple-breakdown operation mode of the load with voltage recovering as the specified time passes after the breakdown. The rated power of the high-voltage power supply is 450 kW. A functional diagram and design of the high-voltage power supply are given.     

高频响双向开关式恒流源设计

针对"现有模拟式恒流源只能单向输出且效率低,而已有的数控式恒流源系统复杂、成本高、响应速度又比较慢"的普遍不足,提出了一种新颖的基于模拟PWM控制器的双向高频响开关式恒流源电路。该方案采用了脉宽调制控制器芯片MCP1630和集成功率H-桥L6201P作为核心,由设定输入电压和高边电流采样反馈所形成误差通过MCP1630内PI闭环实现了电流可控调节。实验测试结果表明,该电流源满载输出范围达±2 A,电流调节精度±5%F.S,响应频宽超过700 Hz;该电流源响应快,功耗和成本低,适应于高速双向比例电磁铁驱动要求。     

A high-voltage power supply of the neutral beam injector

For corpuscular heating of plasma in the FRC plasma plant (USA), six injectors of hydrogen atoms with a 40-keV particle energy, a 25-A equivalent current, and an operation duration of >1 s are designed, manufactured, and put into operation at the Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences (Novosibirsk). For the high-voltage powering of the neutral beam injectors, unique 40-kV high-voltage sources with a 1.7-MW power are designed and manufactured. They have a wide output voltage regulation range and are capable of being promptly switched-off in response to the high-voltage breakdown of the load. The high-voltage power pupplies of the neutral beam injectors are the subdivided rectifiers with a discretely regulated output voltage, and a specific feature of the circuit is the use of additional fast semiconductor switches, short-circuiting the outputs of the rectifying sections. The design circuit and elements are described, and test results of the high-voltage power supplies of the neutral beam injectors are given.     

适用于镁海水电池的能量变换系统设计

本文设计了一种适用于镁海水电池供电的能量变换系统,针对镁海水电池输出特性软、电压低的问题,对传统非隔离型三端口变换器进行优化,使电压增益得到进一步提高。基于此变换器拓扑,考虑镁海水电池输出特性和变换器载荷特性,提出一种适用于载荷突变的DC/DC变换系统能量管理策略,通过控制能量在系统内任意两个端口间的流动,实现源、荷间功率动态平衡;同时,根据镁海水电池的输出特性,在系统能量管理中引入一种基于改进灰狼算法的最大功率点追踪方法,进一步提高了镁海水电池的能量转换效率。最后通过仿真和实验证明,载荷功率在0.36和1.2 W跳变时,变换器能相应完成模式间的切换,在保证输出电压稳定在12 V的前提下,实现了对输出电流30和100 mA的灵活控制,验证了该能量变换系统软硬件设计合理性。     

A high-voltage power supply based on a distributed capacitive energy storage

For the corpuscular plasma heating in the MST plasma device (Madison, United States), an injector of hydrogen atoms with 25-keV energy, equivalent at omic current of >45 A, and 20-ms pulse duration was designed and put into operation at the Budker Institute of Nuclear Physics (Novosibirsk, Russia) in 2009. The pulse repetition rate is 5 min. The output current of the ion source in the atomic injector exceeds 50 A. A high-voltage source with a 1.5-MW power was design ed for the high-voltage powering of the atomic injector. The run duration of the power supply with rated characteristics is >20 ms. The power supply is based on a distributed capacitive energy storage, which allows the power consumption from the industrial network to be reduced down to 10 kW at a pulsed load power of 1.5 MW. The high-voltage power supply smoothly regulates the output voltage from 0 to 30 kV and is capable of being quickly deenergized if high-voltage breakdown of the load takes place. The diagram and structural components of the high-voltage power system of the atomic injector are described, and its test results are given.     

基于周期平均值外特性的脉冲MIG焊弧长稳定性研究

通过对脉冲熔化极惰性气体保护(Metal inert gas,MIG)焊脉冲平均电流电压变化率的计算,提出脉冲周期平均值外特性曲线,并对弧焊电源脉冲周期平均值外特性曲线和电弧静态性曲线的动态稳定工作点进行详细分析,得出利用脉冲平均值外特性控制脉冲MIG焊的控制策略。同时运用双闭环控制实现了基于弧压反馈的I/I模式控制数字化弧焊电源,此电源能在送丝速度稳定情况下自适应弧长扰动变化,实现脉冲弧焊过程一脉一滴熔滴过渡。通过弧长阶跃试验表明,脉冲弧焊过程中焊丝熔化速度快速跟踪弧长变化,具有良好的弧长动态调节性能,保持弧长动态稳定,即焊接过程稳定,焊缝成形良好,同时验证了分析过程正确性和设计过程的可行性。     

电场能量采集器的最大输出功率追踪电路设计*

本文采用频率变换原理采集输电线周围电场能量,设计了一种能量采集电路,对超级电容充电。负载阻抗呈电容性,为非线性负载,充电过程中阻抗不断变化。为实现最大输出功率传输,设计了低功耗的最大输出功率追踪(MPPT)电路,采用频率值为32.768 k Hz石英晶体构成方波振荡电路,因电容电压不能突变,通过充电电流控制开关导通时间,构成电流反馈最大输出功率点追踪系统。最大输出功率追踪电路的工作电流为1.2 u A,工作电压为5 V,功耗为6 u W。实验结果表明,在充电36min时达到最大功率输出,储能电容电压的大小为0.32 V,输出功率最大为18 u W。相比于直接充电电路,最大输出功率电路的能量采集效率提高了50%。     

一种基于金阴极MCP的冷阴极电子源的研制

采用深紫外光子激发金阴极产生的冷阴极电子源具有诸多优点，将其应用于电子轰击离子源(EI)有助于获得高质量的离子源。本实验分别采用在JGS2石英玻璃上蒸镀金薄膜构成透射式金阴极、在微通道板(MCP)输入面蒸镀金薄膜构成反射式金阴极，将二者以不同的组合方式装配在一起，通过施加不同的间隙电压，从而获得较大范围的电子流输出，研制出电子束流可调(10^-11～10^-5 A)、均匀分布(非均匀度6.5%)的稳定输出(稳定工作时间大于5 h)电子源，有望在高质量EI源中得到推广和应用。     

基于开关稳压电源与开关稳流电源并联系统的设计

为了改善电源的性能,提高电源对变化负载的适应能力,设计将开关电压源和开关电流源并联构建供电系统。系统采用电压源与电流源在输出端并联后按比例分配输出电流的方法,解决开关电源并联后供电系统输出不稳定的问题,构建了实际的并联电源系统。实验表明,采用该文的按比例自动分配电流的方法,可以实现电源系统的大功率稳定输出。     

Narrowing of the electron energy spectrum in the ILU-10 accelerator

Results of numerical and experimental investigations of electron energy spectrum narrowing by applying an external boosting HF voltage to the grid-cathode gap of a triode HF gun in the ILU-10 single-cavity pulsed accelerator (electron energy, 5 MeV; mean beam power, 50 kW; operating frequency, 116.3 MHz) are described. These results showed that, without a booster HF voltage, 62% of the beam power is within 5% of the energy spread and, after a booster voltage of the operating frequency is applied, as much as 74% of the beam power falls within these limits. Finally, at a booster voltage of the third harmonic, 93% of the beam power lies within 5% of the energy spread.     

A High-Power Semiconductor Generator for an Atomic Injector

An atomic injector with a beam power of 1 MW for heating plasma in the TCV tokamak (Lausanne, Switzerland) by a beam of neutral atoms was developed and put into operation in 2015–2016 at the Budker Institute of Nuclear Physics SB RAS (Novosibirsk). Plasma in the injector is formed in a plasma emitter by a high-frequency magnetic field, which is created by a high-power semiconductor generator with an output power of 40 kW at a frequency of 4 MHz. The facility operates in the pulse mode with a pulse duration of 2 s and a pause of 5 min. The generator is manufactured in the form of a modular system consisting of 16 identical generator modules, whose high-frequency power is summed, control modules, and a power-supply source. The generator allows modulation of the output power in the range of 30–100% by changing the power-supply voltage. The general structure of the generator and its elements and the results of its commissioning are presented.     

基于小波的全数字逆变焊机信号处理

从强干扰、高压、大电流的恶劣工作环境中,获得逆变焊机有用信号,是全数字焊接电源研发和工艺评判的关键。在分析研究脉冲宽度调制(Pulse width modulation,PWM)驱动原理的基础上,提出先对逆变焊机PWM驱动信号级的电流信号进行去噪,进而实现整个焊接电流信号的噪声滤除方法。构建硬门限阈值函数对信号进行小波分解,对小波分解的详细系数集去噪。同时构建模极大值判别函数,来搜寻详细系数的噪声奇异点,利用搜索结果对近似系数集的噪声进行线性滤除。选择相关参数的合适数值进行仿真试验,结果表明,该去噪方法能够很好地滤除焊接电流的噪声,保证信号不失真,获得有用的信号特征,为全数字逆变电源的研究和性能评价奠定基础。     

ILU-14 industrial electron linear accelerator with a modular structure

A new high-power (up to 100 kW) industrial electron linear accelerator ILU-14 for energies of 7.5–10.0 MeV has been developed by the Budker Institute of Nuclear Physics. The operating frequency of the accelerator is 176 MHz, and the total efficiency is 26%. Owing to the modular structure of the accelerator, the electron energy and the beam power can be varied within certain limits by changing the modular arrangement. A 5-MeV prototype of this accelerator has been produced and successfully tested. Its design parameters verified in the experiments are as follows: the beam current averaged over the RF period is 600 mA, the beam pulse power is 2.5 MW, and the electron efficiency of the accelerating structure is 68%. By applying an additional RF voltage to the electron gun cathode-grid gap, a 96% transmittance of the beam current has been attained at a minor beam energy spread. The prototype of the ILU-14 accelerator can be used as an accelerator with a beam power of 50 kW.     

城市轨道交通直流PWM电源的研制

旨在通过PWM（脉冲宽度调制）,解决城市轨道交通接触网电压的波幅较大和波形畸变严重的问题,并将交流整流成直流;通过PWM,调节电源电路输出脉冲的占空比,控制IGBT主回路的电压,以实现PWM稳定电压的目的。本文研制出1种通用的轨道交通直流PWM电源,其电路包括主电路及控制电路,设计出PCB（印制电路板）并进行试验。试验结果表明,该电源具有稳定和调节电压的功能,达到了电源优质化的目的。     

A forevacuum plasma source of pulsed electron beams

A plasma electron source designed for generation of a pulsed wide-aperture electron beam in the forevacuum pressure range (5–20 Pa) is described. The source is based on the use of a hollow-cathode glow discharge. At an accelerating voltage of 20 kV, a current pulse length of 100 μs, and a pulse repetition rate of 10 Hz, the electron beam current is 100 A, and the maximum density of the beam pulse power is 10 J/cm². The obtained parameters of the electron beam and the features of the source functioning in the forevacuum pressure range show that this source can be used to good effect to modify the surface properties of nonconducting materials.     

The K(a)-band 10-kW continuous wave gyrotron with wide-band fast frequency sweep

The dual-frequency gyrotron with fast 2% frequency sweep at about 28 GHz is designed to power an electron cyclotron resonance ion source (ECRIS). Operation with an output power of up to 10 kW in CW mode and efficiency of 20% was demonstrated at both frequencies. Frequency manipulation has a characteristic time of about 1 ms and is based on magnetic field variation with an additional low-power coil. Fast frequency sweep will supposedly increase the ion current and the average ion charge of ECRIS. The possibility of 100% power modulation is demonstrated using the same control method.     

电子束焊熔深神经网络模糊控制系统建模与仿真

研究钛合金电子束焊熔深控制系统建模问题。在分析电子束焊接特点的基础上,设计三因素五水平正交试验,通过试验得到不同焊接参数下熔宽和熔深的值,将熔宽和熔深的值作为训练样本对神经网络进行训练,建立以熔宽为输入,以熔深为输出的误差反向传播(Error back propagation,BP)神经网络模型,该模型由一个S型函数隐含层加上一个线性输出层组成。针对熔深数学模型难以获得的情况,设计以熔深的偏差和偏差变化率为输入变量,焊接电流的变化量为输出变量的模糊控制器,该控制器有9条模糊控制规则。将BP神经网络模型和模糊控制器结合起来建立钛合金电子束焊熔深控制系统模型,并且采用单位阶跃信号对该模型进行仿真试验,试验结果表明所设计的控制系统动态性能和稳态性能良好。     

波控短路过渡CO_2焊接恒频自适应控制系统

针对短路过渡ＣＯ２焊接工艺的特殊性,基于熔滴与熔池短路阶　段电源输出回路电阻的变化特征,确定了有利于消除瞬时短路及提高熔滴过渡规则性的焊接　电源输出电流波形。在对短路过渡频率及焊丝伸出长度进行实时检测的基础上,采用ＭＣ６８ＨＣ　１１Ａ１单片机为主控ＣＰＵ,　建立了焊丝伸出长度变化前馈补偿—短路过渡频率负反馈控制的波控短路过渡ＣＯ２焊接恒频自适应控制系统,以提高焊接工艺过程的稳定性、抑制焊丝伸出长度变化对焊接工艺过程的扰动。     

A power supply for a technological installation

A voltage changer for the power supply of an ultrasonic piezoelectric transducer is designed on the basis of a resonance inverter. The output filter designed on the basis of a series-resonant circuit with parallel and series compensation ensures matching of the changer to the load. The changer ensures a load current of 0.5A±10% within a wide range of the load resistance (from 50 to 400 Ω) at an input voltage of 220 V±15% with automatic tuning to the frequency of the load mechanical resonance. The changer output power is 100 W, and the output current is a sinusoid with a frequency of 22±2 kHz.