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

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.