燃料电池车用大功率DC／DC变换器电磁兼容性研究

本文对燃料电池电动汽车用大功率DC/DC变换器的电磁干扰源及传输途径进行深入分析,从抑制大功率DC/DC变换器的电磁干扰、控制电路PCB板信号隔离以及软件程序抗干扰三个方面进行大功率DC/DC变换器的电磁兼容性研究,给出抑制燃料电池电动汽车用大功率DC/DC变换器电磁干扰以及提高控制电路板及软件程序抗干扰能力的具体措施,为整车的可靠运行提供了保障.     

基于推挽电路的光伏并网发电微型逆变器研究

随着新能源的逐步推广,光伏并网发电系统得到了发展。其系统通常由多块光伏电池板串联依此提高整个光伏支路电压,通过DC／DC变换器或DC／AC逆变器连接负载或电网。针对以往方式,本文研究了一种由前级推挽正激电路的变换器及后级Dc／Ac逆变器两级联接式的光伏并网发电微型逆变系统。其前级通过光伏电池板最大功率点跟踪进行高频准单极性控制,后级采用流内环,电压外环双闭环控制。仿真研究表明,该系统具有并网电流质量高,动态特性好,最大功率点跟踪精确、效率高、稳定性高等优点。     

输入滤波对直流分布式电源系统稳定性影响的研究

分布式供电直流变换器与逆变器级联系统具有很强的时变和非线性特性,级联式DC/DC变换器的稳定性是分布式供电系统中的重要问题。文中重点以DC/DC变换器与DC/AC逆变器连接为例分析逆变器输入滤波对系统稳定性的影响。通过实验验证,在逆变器侧串联LC滤波器,利于系统稳定。     

电动汽车隔离型DC/DC辅助电源模块的可靠性设计

提出一种新型的电压前馈补偿的准谐振、零电流开关DC/DC变换器电路设计方案,并对DC/DC辅助电源模块电路拓扑结构的进行论证和选择,运用电磁兼容性(EMC)设计方法,研制并开发电动汽车用隔离型DC/DC辅助电源模块。     

浅析几种常见的PFC拓扑

AC/DC变换是电力电子技术在工业生产应用中较重要的一个方面。如何解决AC/DC变换中产生的谐波,以及较低的功率因数已经成为电力电子技术领域中的一个主要研究方向。本文首先从传统的AC/DC变换器拓扑分析入手,引出了功率因数基本定义、低功率因数的危害。在这之后,本文给出并简单的分析了现在常用的一些功率因数校正电路。     

一种应用于电动汽车的双向DC／DC变换器研究

分析和比较了四种非隔离型双向DC／DC变换器的拓扑结构。针对目前广泛使用的混合动力电动汽车存在的环保问题和电池性能问题设计了一种双向DC／DC变换器一两相交错双向DC／DC变换器,论述了其工作原理,并通过一台3000W的样机验证了理论的正确性。     

电力电子装置的EMC设计

为了保证电力电子装置具有良好的电磁兼容性,在产品的设计初期就应当进行EMC设计,这时所花费的代价最低.本文分析了电力电子装置产生电磁干扰的三个要素,提出了针对性的EMC抑制措施,从系统接地、隔离、合理的结构布局和布线、屏蔽、滤波方面进行了EMC设计的分析,对电子设备的电磁兼容性设计提供了一定的参考方法.     

基于TMS320F28XX+UCD8K+HCPL-315J的两级逆变器

介绍以TMS320F28XX、UCD8K和HCPL-315J为核心的单个DSP控制"DC/DC直流变换器 DC/AC逆变器"两级变换逆变器.在介绍整体电路的基础上,详细分析了每个器件的特点及应用.并在500 VA 28 VDC/115 V 400 Hz逆变器样机上进行了实验,验证了设计电路的有效性.     

基于补偿原理的逆变器EMI抑制方法研究

由于逆变器电源对输出接地电容的限制,对严重的共模电磁干扰难以用大容量的共模滤波器抑制共模噪声。文章介绍了一种新型的基于噪声电流补偿原理的电力电子装置无源干扰抑制技术,探讨了不同方案实现对共模噪声电流的补偿,并在一台DC/AC逆变器中进行了补偿测试。实验结果证实了该EMI抑制方法的有效性。     

电动汽车中人体SAR值的FEKO仿真

利用FEKO建立适合电磁仿真的坐姿人体模型和汽车车身模型,对电动汽车的主要电磁辐射源进行简化和仿真,得到在电机、DC/DC变换器、天线这些激励下的车内电磁环境,并对人体及主要器官进行比吸收率（SAR）的仿真计算。结果表明,在100－900 MHz时,车内人体比吸收率都满足限值,其中SAR较大的组织是皮肤与大脑,这为电动汽车中的人体电磁安全研究提供了参考依据。     

新型Buck-Boost逆变器及其控制策略研究

出两个完全相同的独立的buck—boost斩波器,输入并联,输出串联构戚一个DC／AC逆变器,该逆变器实现了单级功率变换,双向功率流,与传统的两级式逆变器相比,具有拓扑结构简单,同时工作的开关元件少,功率密度大,变换效率高等优点。但由于两个斩波器的输出电压要求在较宽范围内变动,故其控制方法和单独的buck-boost斩渡器有所不同,本文对该电路的工作原理和控制方法进行了详细的分析,针对输出电压范围宽的特点,提出了改进的电流控制法,该控制方法采用附加扰动补偿的前馈控制和反馈控制相结合,使两个斩波器的输出电压和逆变器的输出电压都能得到准确的控制,对外界变化能作出快速准确地反应,提高了逆变器对输入电压和负载变化的响应能力。     

基于风力发电系统的电能变换装置研究

针对目前独立运行风力发电系统通过＂交流-直流-交流＂的转换方式供电时,存在能量利用率偏低,且往往达不到负载需求电能的缺点,采用了DC/DC升压及DC/AC逆变技术在风力发电能量转换体系中,设计了一种新型的能量供应体系及其控制策略,并在此基础上应用Matlab/Simulink搭建了仿真程序。通过仿真,得到了用户需要的稳定交流电能,验证了控制策略的正确性及控制方案的可行性,具有很好的推广应用价值和进一步的研究价值。     

GaN HEMT器件封装技术研究进展

GaN高电子迁移率晶体管(HEMT)器件由于其宽禁带材料的独特性能,相比硅功率器件具有击穿场强高、导通电阻低、转换速度快等优势,在智能家电、交直流转换器、光伏逆变器以及电动汽车等领域有着广泛的应用前景。但GaN HEMT器件的高功率密度和高频工作特性,给器件封装带来了极大挑战,要使其出色性能得以充分发挥,其封装结构、材料、工艺等起着至关重要的作用。介绍了GaN HEMT及其组成的功率模块的典型封装结构,并对国内外在寄生电感、热管理等封装关键技术问题的研究现状,以及高导热二维材料石墨烯在GaN HEMT器件热管理中的应用进行了综述。     

Modified Pulse-Adjustment Technique to Control DC/DC Converters Driving Variable Constant-Power Loads

Multiconverter-distributed DC architectures have been utilized for power distribution in many applications such as telecommunication systems, sea and undersea vehicles, an international space station, aircraft, electric vehicles, hybrid-electric vehicles, and fuel-cell vehicles, where reliability is of prime concern. The number of power-electronic converters (AC/DC, DC/DC, DC/AC, and AC/AC) in these multiconverter electrical power systems varies from a few converters in a conventional land vehicle, to tens of converters in an advanced aircraft, and to hundreds of converters in the international space station. In these advanced applications, power-electronic converters might need to have a tight output-voltage regulation. From the output perspective, this property is highly desirable. However, since power-electronic converters are efficient, tight regulation of the output makes the converter appear as a constant-power load (CPL) at its input side. Dynamic behavior of CPLs is equivalent to negative impedance and, therefore, can result in instability of the interconnected power system. In order to mitigate the instability of the power converters loaded by CPLs, this paper presents the pulse-adjustment digital control technique. It is simple and easy to implement in application-specific integrated circuits, digital-signal processors, or field-programmable gate arrays. Moreover, its dynamic response is fast and robust. Line and load regulations are simply achievable using this technique. Analytical, as well as simulation and experimental results of applying the proposed method to a DC/DC buck-boost converter confirm the validity of the presented technique.     

Intelligent magnetic-amplifier-controlled soft-switching method foramplifiers and inverters

This paper proposes a simple efficient soft-switching method for switching power converters, inverters and amplifiers. Soft switching of a DC/AC H-bridge power converter is realized by paralleling two auxiliary switches and a magnetic amplifier with the load. The auxiliary switches are turned on at a predetermined time before the commutation of the main switches. The magnetic amplifier then automatically determines the necessary amount of redirection current to ensure soft switching of all switches under any load conditions. This method requires no expensive sensors or complex control circuitry. It is ideal for class-D audio power amplifiers, where the load current is widely changing. Further applications include DC/DC power converters, motor drivers, uninterruptible power supplies (UPS), communication and space power applications, where high efficiency, low electromagnetic interference (EMI) and small size are crucial     

Power electronic converters for motion control

The historical development of power electronic converters to control electrical machines is traced up to the present state of the technology. The fundamental possibilities to control average power in a switching mode are considered and the concepts switching function, converter topology and converter structure defined. A systematic approach to developing more complicated topologies and structures for singular and composite converters is discussed and application to motion control systems given. A functional classification of motion control converters is also related to the switching nature of the power processing, illustrating the fundamental dilemma of this kind of highly efficient power control. The different control possibilities of using power electronic converters with electrical machines in motion control applications (DC drives, AC drives) are reviewed systematically. The paper does not attempt to compile a comprehensive list of all possible converter circuits and variations but focusses on generic issues and technologies. The switching technology in converters and its limitations is related to snubberless, snubbed, and resonant transition-type operation, with reference also to switch drive and converter protection technology. Some future generic possibilities related to electromagnetic integration of switching converters are discussed, also in relation to a motion control application     

多输入矿用本质安全型电源的设计

该本质安全型电源为交流127/36/24V输入,直流输出为12V/1A,利用AC/DC电源模块LH25-10B12和DC/DC电源模块PF4812MD-25W作为稳压模块,采用双重过压过流保护电路,并具有自动恢复功能。设计电路利用Multisim电子电路仿真软件进行仿真分析并通过试验验证。     

交流调速电梯中的电能质量

因为人们越来越多地使用非线性负载，电网中就存在电源质量问题。在交流传动系统中广泛使用功率变换器，由于其非线性的工作运行状态，导致电压发生畸变，从而影响敏感设备的性能。本文试图分析由功率变换器供电的电梯交流传动系统对电源质量的影响。敏感电气设备和电梯交流传动系统都连接到0．4kV输电线路上。因功率逆变器导致的电压畸变能够导致系统故障甚至电气设备中部分元件的损坏。     

A detailed R-L fed bridge converter model for power flow studies inindustrial AC/DC power systems

Because of lower voltage levels and smaller power ratings, the R/X ratio of commutation impedance in industrial AC/DC distribution systems is usually higher than that in HVDC transmission systems. Considerable discrepancies may therefore occur in industrial AC/DC power flow results, especially the reactive power consumption of converters, if the commutation resistances of the converters are neglected. To describe the effects of commutation impedance on converter operations and to precisely relate the fundamental line current and DC output current of the converter, a detailed model of the bridge converter with commutation impedance for use of Newton-Raphson power flow studies in industrial AC/DC power systems is derived in this paper. A coal mine power system and a DC electrified transit railway system with regenerative braking function, a part of Taipei Rapid Transit Systems under planning, have been analyzed to show the improved accuracy and good convergence characteristics of the developed Newton-Raphson power flow formulation with the proposed converter model