针对现有第4类LLC谐振型DC-DC变流器拓扑种类繁多,研究芜杂的现状,该文在总结第4类LLC谐振型变流器基本特性及分析方法的基础上,从模块电路功能辨识的角度出发,将该类变流器拓扑重新统一构建在一个由若干基本功能电路模块组成的宏模型内,并探求归纳其所有基于此宏模型的功能电路模块准同构拓扑形式。这些拓扑形式保留了第4类LLC谐振型DC-DC变流器的特征和优点,可根据输入输出及磁隔离要求而分类,并具有各自适用的应用场合,是电力电子系统集成优选拓扑类。进而,这些拓扑可柔性改造成诸多变形形式,从而适用于一些特殊应用,例如高压输入及高效率多路输出场合。最后,用一个适用于不间断电源(uninterruptible power supply,UPS)系统后备模式直直转换的样机验证第4类LLC谐振型DC-DC变流器准同构拓扑及变形形式的多样性和在工业应用中的有效性。
针对现有DC-DC变流器对起整流作用的二极管零电流关断软技术研究不足,从而不能进一步减小变流器开关损耗的现状,从二极管零电流关断的定义出发,通过理论分析和实例说明相结合的方式,提出实际电路中二极管零电流软关断的判断方法,并总结和归纳两种实用性整流二极管零电流关断技术和其主要特征。在此基础上,根据实际应用场合的需要,经过的一系列的拓扑推演,提出一族具有斩波管可实现零电压开启、整流管可实现零电流关断特性的新颖拓扑族,实现了开关损耗的最小化,无需外加任何开关管缓冲网络,可适用于双向DC-DC变流场合。一个适用于不间断电源(uninterruptible power supply,UPS)系统的样机验证了该拓扑族的有效性和在实际应用中的优越性。
The magamp (magnetic amplifier) is widely used in power supplies due to its low cost, simplicity and other advan-tages. This paper discusses a novel application of the magamp in switching power supplies, where the magamp is used to regulate pulse width modulation (PWM) instead of power signal in the main circuit. This method extends the application of the magamp in power supplies, and makes it possible to further regulate control signal when PWMs have been generated. Based on this applica-tion, a new current-sharing (CS) scheme using the magamp is proposed, which uses a modified inner loop CS structure. In this scheme PWMs are generated by one main controller, and CS is achieved by regulating PWMs using a magamp in each module. Compared with traditional application of the magamp, the new CS scheme can be used in most topologies and only requires magamps of low power capacity. Then a test circuit of parallel power supply is developed, in which CS is achieved by a PWM regulator with the magamp. The proposed scheme is also used to upgrade an electroplate power to make it capable of paralleling supplies. Experimental results show that the proposed scheme has good CS performance.
