直流微电网DC/DC变流器IGBT均温控制

IGBT Temperature Equalization Control of DC/DC Converter in DC Microgrid

直流微电网并联DC/DC变流器中功率器件IGBT电热参数以及线路参数存在差异性,使得各并联DC/DC变流器中的IGBT承受不同的热应力,热应力差异加剧了DC/DC变流器IGBT疲劳老化失效程度,降低了直流微电网整体供电可靠性。为此,提出一种直流微电网DC/DC变流器IGBT均温控制策略。首先,建立基于Foster热网络模型的IGBT热电耦合模型,并计算分析DC/DC变流器IGBT结温;然后,分析直流微电网并联DC/DC变流器IGBT结温差异的影响因素,通过在传统下垂控制中引入均温虚拟阻抗,自适应调整流经各DC/DC变流器的电流,使得各并联DC/DC变流器IGBT结温趋于一致,并进行所提策略的稳定性分析,实现DC/DC变流器运行可靠性和直流微电网整体稳定性的有效提升;最后,搭建Matlab/Simulink与PLECS/Blockset联合仿真模型,验证了所提均温控制策略的有效性。

The disparity in electrothermal parameters of power devices IGBTs and circuit parameters in parallel DC/DC converters within a DC microgrid causes the IGBTs in each converter to experience different levels of thermal stress.This thermal stress disparity exacerbates the fatigue aging and failure of the IGBTs in the DC/DC converters,thereby reducing the overall power supply reliability of the DC microgrid.Therefore,a temperature equalization control strategy is proposed for IGBTs in DC/DC converters within a DC microgrid.First,an electrothermal coupling model of the IGBT is established based on the Foster thermal network model,and the junction temperature of the IGBTs in the DC/DC converters is calculated and analyzed.Then,the influencing factors of the junction temperature differences of IGBTs in parallel DC/DC converters within the DC microgrid are analyzed.By introducing a temperature equalization virtual impedance into the traditional droop control,the current flowing through each DC/DC converter is adaptively adjusted,making the IGBT junction temperatures in each parallel DC/DC converter converge towards uniformity.The stability of the proposed strategy is analyzed,effectively enhancing the operational reliability of the DC/DC converters and the overall stability of the DC microgrid.Finally,a co-simulation model based on Matlab/Simulink and PLECS/Blockset is constructed to verify the effectiveness of the proposed temperature equalization control strategy.