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ABSTRACT: Single-stage power factor correction converter is preferable in some industrial application due to its characteristic of cost-effective and high power density. Generating principle of flux density bias for transformer involved in single-stage(SS) type full-bridge(FB) PFC converter is detailed analyzed, maximum flux density bias during every line period of input voltage is obtained by recursion. Mathematic model of ferrite loss increment for core resulted by flux density bias is quantitively built and analyzed, moreover the demonstration model is obtained by MATLAB. Suppressing effect of flux density bias(magnetizing density bias) by adopting fully digital control strategy is analyzed, further two digital suppression strategies are presented, and the feasibility and validity of preferable strategy is verified by experimental results. Finally, a prototype, whose maximum output power is about 300 W and PFC frequency is 55 kHz, is built to verify the validation of presented preferable suppression strategy, experimental result of conventional analog control implementation is also given for comparison. Further, conversion efficiency is greatly increased and operating performance is excellent, PF value and efficiency of full load are respectively 0.99 and more than 92%. In addition, conversion efficiency curves of different operating frequency are given for comparison by experiment.
Industrial Electronics Society, 2007. IECON 2007. 33rd Annual Conference of the IEEE; 12/2007
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ABSTRACT: Dedicated to such industry requirements as high power, rigorous harmonic standard and isolation, a novel solution that combines the topology of full-bridge and fully digital controller is presented. This paper deals with a 5 KW power factor correction (PFC) converter that is based on the topology of single-stage (SS) full-bridge (FB) structure with input current shaper and RCD clamping circuit. Especially, the clamping capacitor can partly return its stored energy. A transformer used to provide galvanic isolation allows a wide range of output, offering multi-output solutions. The adopted improved digital strategy features fast dynamic response and excellent steady regulation, in addition, problem of flux density bias for the transformer that occurs in analog control strategy is successfully solved without any auxiliary circuit. Both power stage and density are drastically improved. High power factor and high efficiency are achieved. The excellent performances of the converter are verified by a prototype, whose rating output power is 5 kW and PFC operating frequency is 55 kHz. Furthermore, PF value and efficiency of full load are respective 0.994 and more than 92%.
Power Electronics Specialists Conference, 2007. PESC 2007. IEEE; 07/2007
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ABSTRACT: With limitation of lowest load, multi-output LLC resonant topologies with asymmetrical structures on the main output and auxiliary outputs, wherein, whose auxiliary outputs adopt symmetrical structure, dedicating to multi-output power supply systems which is applied as auxiliary supply of the driving chip for the up and down bridges, are presented in this paper. According to output power level, different configuration of secondary output end can be flexibly adapted. Consequently, the presented topology is a favorable candidate for such application as whose outputs are not symmetrical, i.e. compared with auxiliary outputs, power level of main output is comparatively higher. In addition, all switches of the very topology operate under the condition of ZVS and therefore it is applicable to such occasion as high frequency, high power density. Asymmetrical operating principle between the main output and auxiliary outputs are specified, besides, ZVS operation is analyzed in details, moreover key parameter design considerations are presented. Finally, the analysis above is verified by experimental results
Telecommunications Energy Conference, 2006. INTELEC '06. 28th Annual International; 10/2006
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ABSTRACT: Paper presents a new topology named ZVS active-clamped compensative reset dual-switch forward DC/DC converter, which overcomes the disadvantage of high voltage stress for main switches, and maintains the advantage that duty cycle can be more than 50%. Therefore, this topology is particular suitable for high-line input and wide range applications. In addition, soft switching is achieved for all switches of the presented topology, which improves the efficiency of the converter. In this paper, the operation principles and characteristics of this topology are analyzed in detail Finally, the advantages mentioned above are verified by experimental results.
Industry Applications Conference, 2005. Fourtieth IAS Annual Meeting. Conference Record of the 2005; 11/2005
