环境温度对骚扰电压和谐波测试结果的影响

选取变频空调、定频空调等不同样品,在不同的环境温度下对其谐波和电源端骚扰电压进行测量,发现谐波值和骚扰电压值随环境温度的变化有很大的不同.电磁兼容工程师对此类设备进行检测时应给予高度的关注.     

变频器电网干扰和抗干扰对策

电网中的谐波干扰主要通过变频器的供电电源干扰变频器。电网中存在大量谐波源如各种整流设备、交直流互换设备、电子电压调整设备，非线性负载及照明设备等。这些负荷都使电网中的电压、电流产生波形畸变，从而对电网中其它设备产生危害的干扰。变频器的供电电源受到来自被污染的交流电网的干扰后若不加处理，电网噪声就会通过电网电源电路干扰变频器。供电电源的干扰对变频器主要有：     

基于Vicor HAM模块的PFC电源设计

为了提高用电设备对电能的利用效率,减少其对电网的谐波污染和电磁干扰,同时满足GJB151A-97标准中CE101项目对用电设备的电源谐波要求,研制了一台600 W的功率因数调整电源,即PFC电源。该电源采用美国Vicor公司的高增压谐波衰减（HAM）模块和V375系列DCDC模块,其中HAM模块用于控制电源输入电流,使其相位与输入电压相位保持一致,以减少谐波的产生,DCDC模块将HAM模块输出的直流高压转换为所需的直流电压输。经测试,该PFC电源达到了GJB151A-97中CE101项目对电源谐波抑制的标     

电源接地方式对传导骚扰的影响

根据电源传导发射的测试原理,分析了电源回路DC-I接地方式和DC-C接地方式对传导骚扰的影响,指出了可能出现的四种测试结果.在DC-I配置中,电源返回端与设备的保护地不连接在一起.在DC-C配置中,电源返回端与设备的保护地连接在一起.最后结合高级电信计算架构ATCA的电信服务器电源口传导骚扰的测试,进一步验证了电源接地方式对传导骚扰的影响.     

智能电网建设中分布式电源的规划研究

随着电力行业的快速发展和新的发展问题逐渐出现,最大限度的提升电网体系能源效率成为电力行业发展的重要方向,在不断探索的过程中随着现代科技的快速发展,智能电网出现并得到迅速推广,分布式电源作为智能电网的重要组成部分,其位置、容量等对电网的可靠性、节点电压等方面会产生重要影响,所以智能电网建设中分布式电源的规划受到高度关注,本文为对智能电网建设中分布式电源的规划产生更加全面的认识,提升其规划水平,对智能电网建设中分布式电源的优化规划模型、含分布式电源的配电网潮流计算和改进自适应遗传算法在分布式电源选址和定容中的应用进行研究.     

用于三相工业应用系统宽电压电源

由三相交流电源供电的工业设备往往需要一个辅助电源为控制电路提供稳定的低压直流电压。但是,对这种稳压电源的技术要求比单相电源高得多,其额定输入电压比较高。而且在工业环境中,由于大负载接入电网或者脱离电网,或者由于在某个地方电网出现故障,电网电压常常会出现很大浪涌、长时间跌落或者瞬间下降。这就要求电源能够处理所有这些情况而不会出现故障。     

基于智能整流技术的电网电流谐波补偿方法研究

目前用于电网电流谐波补偿的电器设备,主要以PWM整流器为主。基于PWM整流器的电源产品只能被动地减小自身向电网输出的谐波电流,而对电网中业已存在的电流谐波污染束手无策。为了解决电网中电流谐波污染以及相关联的电压波形失真问题,采用基于SRM(智能整流模块)技术对电网电流谐波进行补偿。仿真结果表明,基于SRM的电力电子装置在从电网吸取电流并在向负载供电的同时,还能对电网电压的波形进行补偿,使电网电压波形接近正弦波形。     

CR200J型动力车控制电源传导干扰现场测试与分析

为研究CR200J型动力车110 V控制电源现场测试的传导干扰问题,介绍了控制电源的电气结构,现场测量了控制电源不同工况下输出电压、电流信号和主断路器闭合工况下输出端口的差模、共模电流信号,并分析了输出电压、电流的特性和输出端传导干扰的频谱.测试结果表明:不控整流产生的二次纹波传递到了输出侧;输出电压、电流纹波较大且输出电压幅值偏低;开关频率附近多个频率点的共模干扰幅值较高.最后,根据测试分析结合现有成熟的技术,给出了控制电源电磁兼容优化的建议.     

稳压并抑制谐波的新型电源

由于电网谐波污染严重，对谐波的抑制已成为供电部门的重要任务。文章介绍一种既能稳压又能抑制谐波的新型电源，它采用串联型有源电力滤波的方法，通过瞬态电压补偿后可得到纯净的三相正弦平衡电压。     

一种基于MSP430F2002的数字式单相正弦波变频电源

设计了实现了一种基于MSP430F2002的数字式单相正弦波变频电源,文中对其软硬件设计、器件参数计算以及设计、测试过程进行了详细的描述.该变频电源的供电电源为36V蓄电池,由MSP430F2002完成了SPWM信号产生、电压幅度和频率调制的功能,经单相逆变电路和LC滤波电路得到电压幅度在0V到30V、频率在1Hz到70Hz之间可调、最大负载电流为1A的正弦交流输出信号,可满足过套管电阻率测井仪器的现场需求,测试结果表明使用MSP430F单片机是实现低功耗、低成本、高可靠性仪器设计的最佳选择.     

高效单级变换式LED驱动电源设计

无论民用或商用领域,功率100 W以下的交流电源都有着巨大的应用需求。由于要兼顾输入谐波电流、功率因数、系统能效等问题,采用临界模式（boundary mode）的AC/DC单级反激式的电源拓扑成为非常完美的小功率直流电源解决方案。它具有高的转换效率,在高端小电源供应器中的应用越来越广泛,特别是在LED照明驱动方面极具优势。文章主要阐释小功率（≤100 W）单级AC/DC转换器的原理,分析其正弦调制原理及获得高功率因数、高能效的原因,并探讨了转换器的功能和优点,最后设计了一个采用仙童FAN6961芯片控制的48 V输出75 W的LED驱动电源,实验验证和批量生产证明本方案设计合理、产品性能稳定、可靠性好,能够有效提高能效、功率因数,避免建筑物内高次谐波电流造成的电源环境污染。     

Four-quadratic DC magnet power supply with fast dynamic responseand low ripple content

The authors discuss a power supply configuration based on a switching converter, with reasonably fast dynamic response and low ripple content, so that the linear power supplies can be replaced in four-quadrant DC magnet power supply applications. A new power supply configuration, based on the combination of a frequency converter and a dual converter with circulating current, is proposed for application in four-quadrant DC magnet power supplies. The dual converter is used with circulating current mode for smooth transition of output current polarity. The frequency converter is used at the front of the dual converter to boost the AC line frequency so that the dynamic response can be improved without increasing the ripple content     

Design of a power-factor-correction converter based on half-bridgetopology

A single-stage AC/DC converter based on a half-bridge topology suitable for low-power-level applications is proposed. The proposed converter has high power factor, low harmonic distortion, and tight output regulations. An asymmetrical control and synchronous rectification are employed to reduce the switching and rectification losses, respectively. The modeling and detailed analysis are performed to derive the design equations. Based on these design equations, a prototype converter has been designed and tested by experiment. This prototype meets the IEC 61000-3-2 regulations with near-unity power factor and high efficiency     

DC harmonic distortion minimization of thyristor converters underunbalanced voltage supply using asymmetrical firing angle

Noncharacteristic harmonics of significant magnitude are produced at the output and input terminals of phase-controlled power converters under unbalanced voltage supply conditions. The concept of switching functions has been proposed before to evaluate the harmonics produced by a phase-controlled six-pulse power converter under both balanced and unbalanced power supply conditions. This paper extends the switching-functions approach to establish analytical equations for the DC output voltage harmonics produced by 12-, 18-, and 24-pulse power converters. The problem is approached from the standpoint of symmetrical voltage components. The increase in distortion under unbalance is caused by the appearance of a second harmonic component. A method, based on an asymmetrical firing angle, to cancel the second harmonic at the power converter output under unbalanced voltage supply is also presented. Cancellation of the second harmonic improves power converter DC output voltage quality     

A digitally controlled switch mode power supply based on matrix converter

High power telecommunication power supply systems consist of a three-phase switch mode rectifier followed by a dc/dc converter to supply loads at -48 V dc. These rectifiers draw significant harmonic currents from the utility, resulting in poor input power factor with high total harmonic distortion (THD). In this paper, a digitally controlled three-phase switch mode power supply based on a matrix converter is proposed for telecommunication applications. In the proposed approach, the matrix converter directly converts the low frequency (50/60Hz, three-phase) input to a high frequency (10/20kHz, one-phase) ac output without a dc-link. The output of the matrix converter is then processed via a high frequency isolation transformer to produce -48V dc. Digital control of the system ensures that the output voltage is regulated and the input currents are of high quality under varying load conditions. Due to the absence of dc-link electrolytic capacitors, power density of the proposed rectifier is expected to be higher. Analysis, design example and experimental results are presented from a three-phase 208-V, 1.5-kW laboratory prototype converter.     

A unity power factor resonant AC/DC converter for high-frequencyspace power distribution system

This paper presents analysis and design of a resonant AC/DC converter topology, suitable for use in an advanced single-phase, sine-wave voltage, high-frequency power distribution system of the type that was proposed for a 20 kHz space station primary electrical power distribution system. The converter comprises a transformer, a double-tuned resonant network comprising of series- and parallel-tuned branches, a controlled rectifier, and an output filter. Symmetrical phase control technique that generates fundamental AC current in phase with the input voltage is employed. Steady-state analysis of the converter in continuous current mode of operation is provided, and the performance characteristics presented. The proposed converter has close-to-unity rated power factor (greater than 0.98), a wide range of output voltage control (0%-100%), low total harmonic distortion in input current (less than 8%), and high conversion efficiency. Finally, selected experimental results of a bread-board converter are presented     

A high frequency AC/DC converter with unity power factor andminimum harmonic distortion

A novel forced commutated AC/DC converter and control strategy is proposed that is able to draw nearly sinusoidal currents at unity power factor from three-phase power lines. The power factor is controlled by adjusting the relative position of the fundamental component of an optimized pulse-width-modulation (PWM) type voltage with respect to the supply voltage. Current harmonic distortion is minimized by the use of optimized firing angles for the converter at a frequency where gate turn-off thyristors (GTOs) can be used. This feature makes this approach attractive at power levels of 100 kW to 600 kW. An 8096 microcontroller is used to minimize the interface hardware requirements. The theoretical analysis of the converter, the control energy, and experimental results for a low-power prototype are presented     

通信电源接地系统设计新观念

根据相关国际标准和我国标准,阐述通信电源接地系统设计新观念和实施原则,介绍通信局（站）交流和直流配电系统的接地技术,包括低压交流配电系统、UPS、高频开关电源和高压直流配电系统的接地方法。此外,还分析了当前实际工程中存在的问题,并提出改进建议。     

一种低功耗原边反馈AC/DC转换器

低待机功耗、高效率的绿色电源已成为未来电源技术发展的方向,国际上已经正式提出六级能效标准。提出了一种采用常规工艺实现的原边反馈AC/DC转换器电路,解决了传统原边反馈AC/DC转换器元器件多、待机功耗大以及用高压特殊工艺实现低待机功耗的成本昂贵等问题。该原边反馈AC/DC转换器能够满足六级能效标准。