高功率因数LLC谐振变换器的研究

发布时间：2018-09-12 12:57

【摘要】：随着科学技术的快速进步,模块化、高频化以及高可靠性的电力电子装置在工业及日常生活中得到广泛的应用。但是,大量电力电子装置广泛的接入电网,会引起电网谐波污染,影响电网的正常工作。因此,发展绿色的、高效的电力电子装置是社会发展的要求。本文以分布式电源系统的前端AC/DC变换器为研究对象,提出了一种两级电路结构的高功率因数LLC谐振变换器装置。前级电路结构为无桥Boost功率因数校正器,后级电路结构为半桥LLC谐振变换器,装置在提高功率因数与电路效率方面效果显著,因此备受关注。本文首先介绍了无桥Boost功率因数校正器的工作原理,并采用平均电流模式作为无桥Boost功率因数校正器的控制方案,实现电压与电流的双闭环控制。本文通过小信号分析法建立了无桥Boost功率因数校正器的小信号模型,推导出系统总的开环传递函数,并利用无损吸收技术改善开关管的开关轨迹,降低开关管两端电压的变化速率。其次,本文对半桥LLC谐振变换器的拓扑结构进行了分析,并通过基波分析法建立了LLC谐振变换器的等效电路模型。在一个谐振周期内,将半桥LLC谐振变换器划分为六个不同的工作模态,详细的阐述了每个模态的工作过程,并从实现宽范围电压增益与高效率的角度出发,优化了谐振槽的电路参数。然后,为了优化电路结构,减小变换器体积,文章讨论了LLC谐振变换器的磁集成技术,将谐振电感与励磁电感集成到同一磁性元件中。最终,设计并制作了一台输出功率为480W的试验装置,并对试验装置进行了系统的调试,测量了装置关键点的实验波形。对测量得到的实验波形进行分析表明：实验样机具有高功率因数、高电路效率等特点。
[Abstract]:With the rapid development of science and technology, modular, high-frequency and high-reliability power electronic devices have been widely used in industry and daily life. However, a large number of power electronic devices are widely connected to the power grid, which will cause harmonic pollution and affect the normal operation of the power grid. Therefore, the development of green, efficient power electronic devices is the requirement of social development. Taking the front-end AC/DC converter of the distributed power system as the research object, a two-stage circuit structure with high power factor LLC resonant converter is proposed in this paper. The former circuit structure is a bridge free Boost power factor corrector, while the latter one is a half-bridge LLC resonant converter. The device has a remarkable effect in improving power factor and circuit efficiency, so it has attracted much attention. In this paper, the working principle of the bridge free Boost power factor corrector is introduced, and the average current mode is used as the control scheme of the bridge free Boost power factor corrector to realize the double closed loop control of voltage and current. In this paper, the small signal model of the bridge free Boost power factor corrector is established by the small signal analysis method, the total open loop transfer function of the system is derived, and the switch path of the switch tube is improved by using the lossless absorption technique. Reduce the rate of voltage change at both ends of the switch tube. Secondly, the topology of half-bridge LLC resonant converter is analyzed, and the equivalent circuit model of LLC resonant converter is established by fundamental analysis. In a resonant period, the half-bridge LLC resonant converter is divided into six different working modes, and the working process of each mode is described in detail, and from the point of view of realizing wide range voltage gain and high efficiency, The circuit parameters of the resonant slot are optimized. Then, in order to optimize the circuit structure and reduce the volume of the converter, the magnetic integration technology of the LLC resonant converter is discussed. The resonant inductance and the excitation inductor are integrated into the same magnetic element. Finally, a 480W test device with output power is designed and manufactured, and the test device is debugged systematically, and the experimental waveform of the key points of the device is measured. The analysis of the experimental waveform shows that the experimental prototype has the characteristics of high power factor and high circuit efficiency.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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