共查询到20条相似文献,搜索用时 171 毫秒
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本文采用“三点频率”的设计方法,从限制第一级、第二级滤波器的谐振频率f1、f2和DC/DC变换器的开关频率f这三个频率点的峰值出发,进行开关电源EMI滤波器的设计,并对主要技术参数——插入损耗进行了理论分析。 相似文献
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本文以开关电源为例,分析了电源EMI滤波器的等效电路,并介绍了用于抑制电源线电磁干扰的滤波器的插入损耗的计算方法,为电源EMI滤波器的设计提供了参考. 相似文献
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基于传导电磁干扰产生机理,对传导 EMI 噪声源阻抗分析仪内阻抗测量的基本原理进行分析,并对比三种噪声源测量方法。利用插入损耗法对某一开关电源进行实际测试,给出了测试结果。 相似文献
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开关电源在雷达电源系统中的广泛应用,使得电网中的电流谐波污染越来越严重.文中通过对雷达电源系统产生的电流谐波的危害分析,提出了采用谐波补偿技术抑制谐波电流的方法.介绍了无源和并联有源谐波滤波器的工作原理及特点,并给出了不同的谐波滤波器在雷达电源系统中的应用测试结果.实测结果表明,谐波滤波器对雷达电源系统产生的谐波电流都有明显的抑制作用. 相似文献
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反激式开关稳压电源传导干扰研究 总被引:1,自引:0,他引:1
开关式直流稳压电源的电磁干扰不仅对电网产生干扰,导致在同一电网上供电的其它设备不能正常工作,而且严重的谐波电压电流会在开关电源内部产生电磁干扰,从而造成开关电源内部工作不稳定,使开关电源性能降低。文中以反激式开关稳压电源为研究对象,主要分析了传导测试中,差模、共模传导两种方式噪声源的产生机理,建立了开关电源传导干扰模型,采用EMI滤波器即共模滤波和差模滤波,并详细研究了加入π型滤波器、输入x电容、共模扼流圈等对开关稳压电源传导干扰的抑制效果,得出传导干扰抑制在标准限制范围的改进措施,整改后可让传导干扰强度从100μV降低到200 nV并通过认证。研究结果表明该措施对抑制开关稳压电源传导干扰是有效的。 相似文献
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Electromagnetic interference (EMI) emission is always of grave concern for power electronic circuit designers. Due to rapid switching of high current and high voltage, interference is a serious problem in switching power circuits. Here, the effect of frequency modulation on power supply EMI noise is investigated. Significant reduction of emission is possible with the proposed scheme 相似文献
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Conducted EMI Reduction in Power Converters by Means of Periodic Switching Frequency Modulation 总被引:1,自引:0,他引:1
Gonzalez D. Balcells J. Santolaria A. Le Bunetel J.-C. Gago J. Magnon D. Brehaut S. 《Power Electronics, IEEE Transactions on》2007,22(6):2271-2281
Spread spectrum clock generation techniques were originally developed to reduce electromagnetic interference (EMI) in communications and microprocessor systems working in the range of hundreds of megahertz. Nowadays, the switching frequency of power converters has been increasing up to values that make worthy the application of such switching frequency modulation techniques to reduce EMI emissions in power converters. Although random modulations have been applied before to power converters, periodic patterns can provide some advantages. First, theoretical principles of frequency modulation using three periodic patterns for the modulating function are presented. The influence of some important modulation parameters on the EMI reduction is analyzed and some considerations about the EMI filters design are also presented. The effectiveness of such methods in terms of EMI reduction is demonstrated theoretically and confirmed with experimental results obtained from tests carried out on two converters. The first one is a 2.5 W buck converter that can be switched up to 1 MHz and the second one is a 600 W boost converter switching at 40 kHz. In both cases, attenuations obtained in conducted EMI are evaluated. Finally, special attention has been paid to input current and output voltage ripple in order to evaluate possible undesired side-effects produced by this technique. 相似文献
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开关电源是采用高速半导体器件来进行电能转换的,开关切换过程中产生的电压电流尖峰造成了严重的EMI问题。常规的DC/DC变换器工作在频率固定的PWM模式下,频谱是离散的,开关频率和低次谐波的能量尖峰很高。文章研究了频率调制技术抑制DC/DC变换器EMI噪声的效果,通过对一台Boost变换器样机进行周期频率调制,证明了频率调制技术对抑制DC/DC变换器EMI的有效性。 相似文献
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在要求低漏电流的电子设备中使用的开关电源不能采用Y电容,但无Y电容的开关电源往往难以通过EMC测试。文中通过分析开关电源中造成电磁干扰问题的原因和解决方法,提出利用吸收电路来抑制无Y电容情况下开关电源的电磁干扰。测试表明,这种方法可以有效解决无Y电容的开关电源中EMI问题。 相似文献
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