输入串联输出并联变换器的控制器设计及稳定性分析方法

Controller Design and Stability Analysis Method for Input-Series-Output-Parallel Converters

输入串联输出并联(ISOP)变换器具有低电压、电流应力、模块化等优点,在高压至低压的功率变换领域得到广泛的应用。以输入电压平衡作为基本控制思想,结合ISOP变换器的等效双闭环控制框图,提出了相应的控制器设计方法及稳定性分析方法,在简化了控制器设计流程的同时提高了稳定性分析的可靠性。为了验证该方法的有效性,选取了双向高效能软开关DC-DC变换器——全桥LLC谐振变换器作为研究对象,对其小信号控制模型进行了进一步的推导和完善,并结合实例,完成了控制器的设计和稳定性的分析。最后,搭建了基于全桥LLC谐振变换器的2单元ISOP变换器实验平台,从起机过程、负载切换过程和功率平衡效果3个方面对上述结论进行了实验验证。

Input-series-output-parallel (ISOP) converter has the advantages of low voltage stress,low current stress and modularity,thus it's widely used in high voltage to low voltage applications.A double closed-loop control diagram based on input voltage sharing is studied and the corresponding controller design and stability analysis method are proposed which can not only simplify the controller design procedures but also make benefit for stability analysis.To verify the validity of above method,a very popular bi-directional soft-switching DC-DC converter: LLC full-bridge resonant converter is selected to study.On the basis of existing research,the small signal control model is further derived and improved.Then the controller design and stability analysis are conducted with example.Finally,a two-cell ISOP converter using LLC resonant converter is set up and the above conclusions are verified by the following aspects: start-up process,load change process and power sharing effects.