High Efficiency Liquid Cooling System of Power Electronic Converter

The failure rate of power devices increases exponentially with the rise of temperature, and the heat generated by large power and small volume will be more concentrated, so it is urgent to study the high efficiency cooling system. The topological structure of power electronic converter is analyzed, the losses calculation method of power devices is summarized. This paper concludes the main heat transfer modes of liquid cooling system, establishes the thermal resistance model of liquid cooling system, and analyzes the distribution characteristics of temperature field and velocity field. The method of increasing the area of heat convection by establishing several small channels is put forward. The influence of different rib thickness and different channel gap on the thermal resistance of liquid cooling radiator, as well as the influence of different flow velocity on the cooling effect are further studied. Finally, a liquid cooling system with the functions of real-time temperature monitoring and flow velocity feedback regulation is designed. This design approach is applied to high power DC charging equipment and motor driver. The volume of the liquid cooling radiator is one-sixth of that of the air cooling radiator, at the same volume and flow velocity, the temperature rise of multiple small channels structure is fourteen Celsius degree lower than that of single channel structure.