Small-Signal Model for Dual Active Bridge Series Resonant DC-DC Converters with Variable-Frequency and Phase-Shift Modulation

变频+移相控制的双有源串联谐振DC-DC变换器的小信号建模

¹ School of Automation, Northwestern Polytechnical University, Xi’an 710072, China
² Department of Information Engineering, University of Padova, Padova 35131, Italy

Received: 27 September 2018

Abstract

Variable frequency and phase shift modulation can achieve zero-voltage switching (ZVS) of dual active bridge series resonant DC-DC converters(DABSRCs) over a wide operating range so as to effectively improving system efficiency and reliability. In order to study the dynamics of DABSRCs and provide the basis for the closed-loop compensator design, a continuous-time small-signal model is proposed. The generalized average modelling approach is adopted, in which the DC component of the output voltage and the fundamental component of the inductor current and resonant capacitor voltage are selected as the state variables, precisely describing impacts of the resonance on the system dynamics. On the above-mentioned basis, a closed-loop compensator is designed, which achieves the stable operation with the ZVS variable frequency and phase shift modulation. The analysis results are verified by the simulation and experimental results.

摘要

变频+移相双自由度控制技术能够实现双有源串联谐振DC-DC变换器在宽范围工况下的零电压开通，从而有效提升变换器的工作效率和可靠性。提出了变频+移相控制下双有源串联谐振DC-DC变换器的小信号连续域模型，为研究在该控制机制下变换器的动态特性和闭环控制器的设计提供依据。所建立的模型基于广义平均建模法，选取输出电压的直流分量和电感电流、谐振电容电压的基波分量作为状态变量，准确描述了谐振腔对变换器动态特性的影响。在此基础上设计了输出电压闭环调节器，实现了变换器在ZVS变频+移相控制下的稳定运行。理论分析通过Matlab/PLECS仿真和1台800 W原理样机进行了验证。