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Power supply for generating frequency-variable resonant magnetic perturbations on the J-TEXT tokamak
To further research the response of the tearing mode(TM) to dynamic resonant magnetic perturbation(DRMP) on the J-TEXT tokamak, a modified series resonant inverter power supply(MSRIPS) with a function of discrete variable frequency is designed for DRMP coils in this study. The MSRIPS is an AC–DC–AC converter, including a phase-controlled rectifier, an LC filter, an insulated gate bipolar transistor(IGBT) full bridge, a matching transformer, three resonant capacitors with different capacitance values, and three corresponding silicon controlled rectifier(SCR) switches. The function of discrete variable frequency is realized by switching over different resonant capacitors with corresponding SCR switches while matching the corresponding driving frequency of the IGBT full bridge. A detailed switching strategy of the SCR switch is put forward to obtain sinusoidal current waveform and realize current waveform smooth transition during frequency conversion. In addition, a resistor and thyristor bleeder is designed to protect the SCR switch from overvoltage. Manufacturing of the MSRIPS is completed, and the MSRIPS equipment can output current with an amplitude of 1.5 kA when its working frequency jumps among different frequencies. Moreover, the current waveform is sinusoidal and can smoothly transition during frequency conversion. Furthermore, the transition time when the current amplitude rises from zero to a steady state is less than 2 ms during frequency conversion. By using the MSRIPS, the expected discrete variable frequency DRMP is generated, and the phenomenon of the TM being locked to the discrete variable frequency DRMP is observed on the J-TEXT tokamak. 相似文献
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根据无线信号传播方式的特殊性,重新定义了无线组播路由中的代价和时延函数,基于图论中最小连通支配集(MCDS)理论,提出的基于图论中点着色思想的时延定界组播转发结构的构建方法,通过求解MCDS来实现构建最小代价组播路由结构的目的,提出了组播路由时延定界的概念,并在该约束下构建MCDS。理论推导证明了该算法的正确性,与同类算法相比,较低的近似比证明了该算法的有效性,同时具有O(n)的时间复杂度和O(n)的消息复杂度,进一步证明了其高效性,具有适应于灵活多变的Ad hoc网络的优势。 相似文献
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电力已经成为我们生活的基本保障,随着电力需求侧的迅猛扩张,供给侧的规模和容量也在不断加大,高压输电系统的室内热环境保障成为一项至关重要的任务。高压换流场是功能目标明确的能源站建筑,与普通办公、商场等商业建筑相比,换流场不仅对温度要求高,而且对于工作区域的温度分布均匀性要求也高,因此需对其进行精准的空间环境控制,保障直流场设备高效运行。从高压换流场环境研究着手,针对其设备环境的要求,提出分区靶向送风系统设计,并对高压换流场进行分区方案设计。靶向送风针对换流场内散热设备降温,分区主要考虑降低空调系统能耗,相比于传统方案更精准、更高效、更节能。以某一高压换流场为例,将研究空间分为电抗器区域内和电抗器以外空间,针对两个区域环境的不同特点,对其进行不同的方案设计,与传统方案进行比较,分析其在高压换流场内的环境调节效果;利用FLUENT,模拟出研究空间运用分区靶向送风方案的温度分布效果,分区靶向送风方案能够将特高压直流场内环境温度降至平均温度33.4℃,远低于要求温度40℃,由此可见分区靶向送风方案能够有效降低温度,均匀空间分布温度场,对高压换流场内环境起到很好的调节作用,从而保障电力设备不间断安... 相似文献
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吸收剂含量对电磁吸收喷墨油墨印刷适性的影响 总被引:1,自引:1,他引:0
目的制备性能优异的电磁吸收喷墨油墨,研究电磁吸收剂含量对油墨印刷适性的影响。方法测试吸收剂含量不同时的电磁吸收油墨的粒径、表面张力、粘度、光固化速度,研究电磁吸收剂含量的变化对电磁吸收喷墨油墨印刷适性的影响规律,获得最合适的电磁吸收剂用量。结果当吸收剂质量分数为0.025%,0.05%或0.1%时,油墨粒径在200~300 nm范围内呈现正态分布;当吸收剂质量分数为0.2%时,大部分油墨的粒径超过500 nm,分散性相对较差。随着电磁吸收剂质量分数的增加,油墨表面张力和粘度均呈下降趋势。当吸收剂质量分数为0.025%和0.05%时,油墨表面张力分别为25.76,25.94 m N/m,油墨粘度分别为0.1354,0.1083 Pa·s,均与喷墨3D打印机专用树脂表面张力和粘度接近。此外,该2种油墨光固化过程中的相对反应速率与3D打印机专用树脂也较接近。结论经综合考虑,当吸收剂质量分数为0.05%时的油墨印刷适性和固化速度最佳。 相似文献