The Component-Multi-Used Theory And Methodology For The Power Electronic Conversion System

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.