面向中压交直流配电网的高频链直流固态变换器损耗模型和分析

Loss model and analysis of high-frequency-link DC solid state converter for medium voltage AC/DC distribution grid

高频链直流固态变换器(DCSSC)是中压交直流配电系统的关键设备之一。针对传统方法未考虑硬开关运行问题,本文提出了一种基于输入串联输出并联双有源桥的高频链固态变换器损耗计算方法。分析了高频链直流固态变换器软开关和硬开关工况下的工作原理,给出了不同阶段下开关器件有效导通时间,推导了软开关和硬开关下的电流平均值和有效值解析模型。建立了高频链直流固态变换器的通态损耗和开关损耗模型,给出了改进型高频变压器损耗计算方法。最后通过Matlab和PSIM仿真软件在开关频率和传输功率变化情况下对高频链固态变换器的各部分损耗分布和系统效率进行了验证和分析。

The high-frequency-link DC solid state converter(DCSSC)is one of the key equipment in the medium voltage AC/DC distribution system.In view of the fact that traditional methods do not consider hard switching operation mode,a loss calculation method is proposed for DCSSC based on input series output parallel(ISOP)dual active bridge(DAB).The operation principle of high-frequency-link DCSSC is analyzed under soft switching and hard switching conditions,the effective conduction time of switch devices under different stages is given,and the analytic model of the current average and RMS values of soft switch and hard switch are derived.The model of conduction loss and switching loss is established,and the improved loss calculation method of high frequency transformer is given.Finally,the loss distribution and system efficiency of high-frequency link DCSSC are verified and analyzed by Matlab and PSIM simulation software under switching frequency and power transmission change condition.