Research On Loss Analysis And Thermal Design Of Power Converter

With the development of power electronics, the power level of power electronics converter is getting higher while the volume and weight of power electronics converter is getting smaller, and result in higher power density and higher junction temperature of converter device. High junction temperature will affect the performance and service life of power devices. In recent years, practice has shown that temperature has become the main reason for power device damage. Since power devices are key components in the converter, the status of their work directly affects the system reliability. To improve the reliability of the system, thermal design is an essential part of converter design.This paper takes converter system as research subject and discusses its temperature rise and heat dissipation, intensive study the power loss of converter power device. Power loss calculation formulas of different converter structure are derived, and be verified with thermal simulation and experimental. Furthermore, this paper establishes the temperature rise calculation model of steady-state and transient with the thermoelectric equivalent circuit, and solves the calculation problem of temperature rise. This paper has written an application software called "Converter temperature calculation simulation software". The software provides basis for converter thermal design, while the calculation and development cost will be reduced with it.Finally, the cooling system of100kW there-level bidirectional DC-DC converter is designed. Through the calculation of power loss and temperature rise, determine the cooling need of the converter. According to the temperature rise calculation, the circuit structure of the converter is improved for to reduce the temperature rise. At last, the cooling system is designed and optimized with thermal simulation software, and be verified with compare to the actual temperature experiment result.