集成谐振单元及嵌入谐振模态的AC/DC变换器关键技术研究

The hard-switching of power devices results in the lower efficiency and power density of the conventional single-stage AC/DC converters, which directly affects the energy-saving effect. In order to maximize the conversion efficiency and power density, and reduce the cost, the key technical issues for single-stage AC/DC converters are addressed in this proposal. Aiming at the high bus voltage, the difficulty of design of resonant parameters, and the limited ac input voltage of the single-stage AC/DC converter formed by integrating the resonant cell, the hybrid control strategy is firstly presented in this proposal. Furthermore, the related DC gain analysis and small-signal modeling issues are studied under the proposed hybrid control. Compared with the conventional topology-based solution, the proposed method has the lowest implementation cost. In order to improve the magnetic and power device utilization, and reduce the turning-off current, the traditional PFC concept based on triangle or saw-tooth type current waveform is break and the novel AC/DC converter is firstly proposed by incorporating resonant mode. the proposed AC/DC converters combline the advantages of PWM and resonant converters. Thus, the studied converter has many features, such as simple duty control as PWM converters, and soft-switching as resonant converters. Moreover, a family of the valuable topology is invented. In the next section of the proposal, the optimal design of power stage parameters and the control method are studied and concerned to make these converters achieve the high PF value, high efficiency and power density. Finally, the hardware prototype has been built and tested in the laboratory, and the experimental results are presented to verify the effectiveness and advantages of the proposal.

传统的单级AC/DC变换器因开关管处于硬开关状态，致使效率和功率密度很难做高，影响了节能效果。项目以提高AC/DC变换器效率和功率密度，降低实现成本为目标，就其中的关键技术问题进行研究。针对集成谐振单元的单级AC/DC变换器中间Bus电压过高、谐振参数设计困难及输入电压受限等问题，从控制的角度，首次提出了混合控制的思想及实现技术，并就混合控制下的建模分析问题进行研究。相较于现有基于拓扑的解决方法，该方法具有最低的实现成本；针对传统硬开关AC/DC变换器中开关管关断电流大、磁性元件及功率器件利用率低的问题，打破传统以三角波或锯齿波电流实现功率因数校正的思维定势，首次提出了嵌入谐振模态的AC/DC变换器概念，发明了一系列具有实用价值的电路拓扑；研究了嵌入谐振模态AC/DC变换器的参数优化设计和控制方法，在保证PF值的同时，提高了该类型变换器效率及功率密度。实验结果证明了研究的先进性和可行性。

传统的单级AC/DC变换器因开关管处于硬开关状态，致使效率和功率密度很难做高，影响了节能效果。项目以提高AC/DC变换器效率和功率密度，降低实现成本为目标，就其中的关键技术问题进行研究。主要研究成果包括： (1) 针对提出的PFM调制Boost PFC集成半桥LLC的单级式软开关AC-DC变换器，因占空比固定为0.5，致使Bus电压过高无法工作于Universal-Input电压的。提出了将Bus电压进行前馈的准恒定Bus电压双闭环混合控制策略；(2) 针对Boost PFC集成Half-bridge LLC的单级式软开关AC-DC变换器输出功率受限的问题，提出了单级交错并联Boost-LLC的AC/DC变换器拓扑; (3) 针对PFM控制存在的问题，提出了基于输出电压反馈、Bus电压比例前馈及双补偿环路的PFM/PWM混合控制策略。数字控制300W原理样机的实验结果证明了控制策略与优化设计的可行性和合理性；(4) 针对定频移相控制LCC 谐振变换器软开关范围窄、辅助网络的增加又不利于变换器小型化的问题，提出了PWM-PFM 混合控制LCC 谐振变换器；(5) 提出了一种类图腾柱的嵌入谐振模态的无桥AC-DC 拓扑，该拓扑相对于图腾柱PFC拓扑，不需要考虑正负半周改变主控管的问题。目前正在采用GaN HEMT进行实验验证。进一步，提出了COT控制的CRM、DCM嵌入谐振模态的AC/DC变换器拓扑以及COT控制的无桥石嵌入谐振模态的AC/DC变换器拓扑。该部分成果正在进行成果整理，预计发表SCI论文2篇。此外，课题组还开展了无线传能、双向CLLLC DC-DC变换器、MHz LLC-DCX以及J 用电源模块的研究工作。. 研究成果解决了传统单级AC/DC变换器的转换效率低、工作范围受限、可靠性差等问题，提升了AC/DC电源的性能和拓展了其应用范围，对优化相关电源产品性能、降低成本、节能减排具有重要意义。

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