【作者】 陈宇；

【导师】 康勇；

【作者基本信息】 华中科技大学 ， 电气工程， 2011， 博士

【摘要】 电力电子技术在传统领域和高新技术领域中均扮演着重要的角色。在实际应用中,通常需要多个电力电子变换器共同协作。这些共同协作的电力电子变换器组成了电力电子变换系统。尽管不同应用场合对电力电子变换系统的性能要求有所不同,但低成本、高功率密度和高效率始终是系统设计的共同目标。本文首先对电力电子变换系统中的元件复用研究现状进行回顾,指出元件复用是降低系统成本、提高系统功率密度和效率的有效途径。基于研究现状,本文分析了元件复用的优势,指出研究现状的不足,并提出了对元件复用拓扑进行系统化设计这一思路。为了展开对元件复用的研究,本文首先以单输入多输出直流变换系统为切入点。为了在已复用隔离变换器和原边元件,且原边功率开关已用于控制一路输出的情况下,仍能实现其它支路输出电压的完全调节,本文提出了互补脉宽的概念,并依此推导出一种利用相移和开关频率进行控制的全桥双路输出互补脉宽变换器。该变换器无需增加额外的可控元件即可实现两路输出电压的精确调节,同时可实现原边功率开关的零电压开通(ZVS)。针对该变换器电压应力较高、导通损耗较大和频率变化范围较宽的缺点,本文对互补脉宽的概念进行了拓展,依此推导出一种仅由半导体、电容和隔离变压器组成的改进型全桥双路输出互补脉宽变换器,不但实现了两个支路输出电压的精确调节,实现了所有功率半导体的软开关运行,同时还减小了开关频率的变化范围。隔离变压器和原边元件均复用的设计方案使各支路之间严重耦合。为此,本文对另一种元件复用的设计方案,即保留各支路的隔离变压器,仅复用桥臂的设计方案展开研究。对已有的ZVS桥臂复用变换器进行了分析,提出零电流开关(ZCS)桥臂复用的概念,使功率开关的类型、软开关模式和器件功率容量得以充分匹配,并依此推导出一种复用滞后ZCS桥臂的多路输出变换器。该变换器的每一支路均具有独立的隔离变压器和独立的ZVS超前桥臂,但复用同一个ZCS滞后桥臂,各支路输出可通过独立超前桥臂与复用滞后桥臂之间的相移来调节。此外,各桥臂均可实现软开关,同时还能方便地实现输出支路的扩展。目前对单输入多输出直流变换系统的元件复用设计尚无系统性的指导方法。为此,本文将用统一的观点对各种多路输出变换器进行归纳,建立单输入多输出直流变换系统的元件复用理论与方法。以最基本的Buck、Boost和Buck-Boost变换器为演化基础,以单输入多输出直流变换系统的需求为演化约束,以一个工作周期内的能量转移为分析思路,本文推导出三个系列的并入型基本元件复用拓扑,并进一步给出了元件复用拓扑的支路扩展准则。以此为依据,本文建立了基本元件复用拓扑与已有多路输出变换器之间的一一对应关系。为增强元件复用设计方法的普适性,本文将单输入多输出直流变换系统的元件复用设计方法拓展至级联型以及多输入单输出直流变换系统。本文给出了另外两个系列的串入型基本元件复用拓扑,并针对不同变换系统的需求,给出了元件复用拓扑的演化规则。以此为依据,本文建立了基本元件复用拓扑与级联型和多输入单输出直流变换系统中各具体电路之间的一一对应关系,并对基本元件复用拓扑的适用场合进行了归纳和总结。最后,本文对元件复用设计方法的可行性进行了初步的探讨,以分布式发电中的一种典型变换系统为例展开设计,给出了多种元件复用的设计方案。为增强元件复用拓扑的应用潜力,本文还提出了三个相关的研究方向,即如何对元件复用的具体电路进行优化,如何把元件复用设计方法推广至交流变换系统以及如何对元件复用拓扑进行控制。更多还原

【Abstract】 Power electronic conversion technology plays the important role in either the traditional or the high-tech field. The actual applications usually require several power electronic converters to cooperate. These cooperated power electronic converters make up of the power electronic conversion system (PECS). The requirements of the PECS for different applications are variable; however, low cost, high power density and high efficiency are always the common objects for the system design.The component-multi-used (CMU) topologies applied in the PECS are first reviewed in this paper, and it is pointed out that the CMU method is an effective path to reduce the cost, increase the power density and efficiency. Based on the survey, the advantages of the CMU method are analyzed, the deficiencies of the presented research are discussed, and the systematic design method for the CMU topologies is suggested.The study will start with the single-input-multi-output (SIMO) DC conversion system. To keep the rest outputs still being regulated even when the switches in the primary-side have been used to control one of the outputs, and the transformer, as well as the primary-side components have been shared, the complementary pulsewidth modulation (CPWM) concept is proposed, and a full bridge dual-output CPWM converter with phase-shifted and pulse frequency modulation is deduced. This CPWM converter can provide two fully regulated outputs without additional switches. Besides, this converter can also realize the full range zero-voltage-switching (ZVS) for all the primary-side switches. To overcome the disadvantages of the original CPWM converter such as the high voltage stress, high conduction loss and wide frequency variation range, the CPWM concept is further extended, and an improved CPWM converter, which only includes the semiconductors, the capacitors and the transformers, is presented. This improved converter not only provides the fully regulated outputs, realizes the soft-switching for all the semiconductors, but also decreases the switching frequency variation range.Sharing the transformers and the primary-side components makes the serious interactions among the branches. To solve these problems, another type of CMU method, i.e., the CMU method that remains the independent transformers but shares the bridge-leg is studied. The existent shared ZVS leg topologies are analyzed and the shared zero-current-switching (ZCS) lagging leg concept, with which the type of the switches, the type of the soft-switching and the capability of the device are perfectly matched, is proposed, and a multi-output converter with shared ZCS lagging leg is deduced. Each branch in the proposed converter includes the independent transformer and leading ZVS leg, but the shared ZCS lagging leg. Each output can be fully regulated by using the phase-shifted between the independent leading leg and the shared lagging leg. Besides, all legs can achieve soft-switching and the amount of the new output can be easily extended.Since there has been no systematic guideline for the CMU design in the SIMO DC system yet, the generalization for the CMU topologies will be performed and the universal CMU theory and methodology will be proposed in this paper. Based on the classical Buck, Boost and Buck-Boost converters, restricted by the requirements of the SIMO system and analyzed on the energy transfer point of view, three series of basic parallel-type CMU topologies are deduced, and the extension rules for the CMU topologies are further provided. Based on these, the relationships between the CMU topologies and the existent multi-output converters are built.To enhance the generalization of the CMU design method, the CMU design method will be further extended to the cascaded and the multi-input-single-output (MISO) system. A new type of CMU topologies, i.e., the series-type CMU topologies, is presented. The deductive restrictions adapted to different system are proposed. Based on these restrictions, the relationships between the basic CMU topologies and the existent circuits are built. Besides, the suitable applications of the CMU topologies are summarized. Finally, the application of the CMU design method is explored, a typical PECS applied to the distributed generation system is chosen as the design example and several CMU designs are given.To enhance the potential of the CMU topologies, three related research fields, i.e., how to optimize the CMU topologies, how to extend the CMU design method to the AC conversion system and how to control the CMU topologies are mentioned briefly.更多还原