一种新型的宽输入高功率密度电源变换拓扑

A Novel Power Topology with Large Scale Input Voltage and High Power Density

针对航空电子设备供电系统输入母线范围宽,需求功率大,尺寸受限的需求,文中提出一种两级式直流-直流(DC-DC)变换拓扑,该拓扑采用谐振变换器(LLC)+交错降压式变换器(Buck)两级变换拓扑,为保证电路处于最优转换效率状态,LLC为定频开环控制,工作频率略低于电路的谐振频率。两路Buck工作于闭环调压模式,采用相同占空比,相位差180°交错控制方式。主功率变压器采用原边串联副边并联的工作方式。针对用电单元存在脉冲取电的工况,设计电压环和电流环串联的控制方式,实现同时对输出电压和电流的有效控制。针对该拓扑的工作方式、控制模式、参数设计进行了分析。最后,采用Saber仿真验证拓扑、搭建实物验证方案的可行性。

Aiming at the problem that the situation of scale power bus,large transmitting power and limited size for avionics power supply system,a two-stage series DC-DC transformation topology is proposed in this paper,this topology is resonant converter(LLC)and interleaved step-down power converter(Buck).In order to ensure the optimal conversion efficiency of circuit work,the LLC works at open-loop state with constant frequency,the frequency is lower than resonance frequency.The output voltage regulation is achieved by the two-way Buck which is regulated by the same duty and phase difference 180°.The transformer is series original edge and parallel secondary edge.Aiming at pulsed electricity characteristics of radar,a control method is proposed which is the series of voltage control loop and current control loop;this method can realize the control of the output voltage as well as the current.The working mode and control mode of this topology is analyzed.Finally,the theoretical analysis is validated by Saber simulation and practicality experiments.