LCC谐振DC-DC变换器研究

发布时间：2018-03-03 20:30

本文选题：LCC谐振变换器　切入点：基波分析法　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着信息产业的发展,对电源的效率和功率密度的要求越来越高。比如,美国"80 PLUS"认证的钛金电源,要求全负载范围效率高于90%,半载效率高于96%。高频谐振DC-DC变换器具有电磁干扰(Electromagnetic Interference,EMI)小、效率高等优点,得到了广泛应用。LCC谐振变换器结合了串联谐振变换器(Series Resonant Converter,SRC)和并联谐振变换器(Parallel Resonant Converter,PRC)的特点,同时具有轻载效率高、输出电压纹波小等优点,在服务器电源等场合具有很大应用潜力。SRC和PRC变换器电路结构简单,理论研究已相当成熟,但LCC谐振变换器谐振元件较多,模态分析复杂,理论研究较少,时域分析无法得到解析表达式;基波分析法(Fundamental Harmonic Analysis,FHA)只考虑基波,并且简化了整流桥的等效模型,分析过程简单,但误差较大;扩展基波分析法(Extended Fundamental Harmonic Analysis,EFHA)同样只考虑基波,但建立了整流桥的精确等效模型,误差较小;高次谐波分析法(High Order Harmonic Analysis,HOHA)分别对各次谐波等效模型进行计算,理论上为精确分析方法,但需要数值解法才能得到最终结果。本文对比研究了四种主要的分析方法,详细研究推导过程并对比优缺点,为业界应用提供参考。LCC谐振变换器的工作特性,由各谐振元件参数以及变压器匝比共同决定,表达式繁琐,工作区域难以界定,参数设计复杂,因此,研究LCC谐振变换器的工作特性和关键指标优化策略具有重要意义。采用EFHA进行分析,明确变频控制和移相控制的LCC谐振变换器的工作区域,并结合MATLAB绘图,展示变换器的特性与参数之间的定性关系,指导变换器元件参数设计工作。移相控制LCC谐振变换器开关频率固定,噪声频谱窄,磁性元件容易设计,具有一定的应用价值。然而,轻载时移相控制LCC谐振变换器滞后桥臂开关管容易失去零电压导通(Zero Voltage Switch,ZVS)特性,针对这一问题,引入辅助谐振换流极(Auxiliary Resonant Commutated Pole,ARCP),提出了 ARCPLCC 谐振变换器。重载时,变换器自身能够实现ZVS,ARCP不工作;轻载时,ARCP投入工作,提供辅助电流,帮助滞后桥臂开关管实现ZVS。理论分析表明,ARCPLCC谐振变换器轻载效率比硬开关移相控制LCC谐振变换器效率高。最后,实验结果验证了理论分析的正确性。
[Abstract]:With the development of the information industry, the efficiency and power density of the power supply are becoming more and more demanding. For example, the "80 PLUS" certified titanium gold power supply in the United States, The full load range efficiency is higher than 90 and the half load efficiency is higher than 96. The high frequency resonant DC-DC converter has the advantages of small electromagnetic interference and high efficiency. The widely used. LCC resonant converters are combined with series Resonant converters and parallel resonant converters parallel Resonant converters. At the same time, they have the advantages of high efficiency of light load and low ripple of output voltage. The circuit structure of SRC and PRC converters is simple and the theoretical research is quite mature, but the resonant components of LCC resonant converters are many, the modal analysis is complex, and the theoretical research is less. No analytical expression can be obtained by time domain analysis. Fundamental Harmonic Analysis (FHAA) only considers fundamental waves, and simplifies the equivalent model of rectifier bridge. The analysis process is simple, but the error is large. Extended Fundamental Harmonic Analysis (EFHAA) also considers only fundamental waves. But the accurate equivalent model of rectifier bridge is established, and the error is small. The high Order Harmonic analysis method of high order harmonic analysis is used to calculate each harmonic equivalent model, which is an accurate analysis method in theory. But the numerical method is needed to get the final result. In this paper, four main analytical methods are compared, the derivation process is studied in detail, and the advantages and disadvantages are compared, which provides a reference for the application of .LCC resonant converter. It is determined by the resonant component parameters and transformer turn ratio. The expression is cumbersome, the working area is difficult to define, and the design of the parameters is complicated. It is of great significance to study the working characteristics and key index optimization strategies of LCC resonant converters. The working area of LCC resonant converters with frequency conversion control and phase shift control is determined by EFHA analysis, and combined with MATLAB drawing, It shows the qualitative relationship between the characteristics and parameters of the converter, and guides the design of the converter component parameters. The phase-shift control LCC resonant converter has fixed switching frequency, narrow noise spectrum and easy design of magnetic components. However, the light load time shift control LCC resonant converter is easy to lose the ZVSs characteristic of zero voltage conduction zero Voltage switch. In this paper, the Auxiliary Resonant Commutated Poledoff (ARCP) converter is introduced, and the ARCPLCC resonant converter is proposed. Under heavy load, the converter can realize the ZVS ARCP not to work, and the light load converter can be put into operation to provide the auxiliary current. The theoretical analysis shows that the light-load efficiency of the ARCPLCC resonant converter is higher than that of the hard-switching phase-shifted LCC resonant converter. Finally, the experimental results verify the correctness of the theoretical analysis.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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