Electrothermal and Electromagnetic Analysis and Thermal Management Design of Core-replaceable Film Capacitors

The development of lightweight and high power density motor controllers for new energy vehicles has brought new challenges to the high temperature resistance of film capacitors inside motor controllers. This paper takes a core-replaceable film capacitor as the research object, conducts electrothermal and electromagnetic simulation analysis on it through ANSYS simulation software, explores the influence of input ripple current effective value, busbar thickness and coolant flow rate on electrical, magnetic and thermal parameters, and designs a water drop-shaped cross-section cooling channel plate for thermal management of the capacitor. The results show that the effective value of ripple current, busbar thickness and coolant flow rate have a direct impact on the maximum temperature of the capacitor core. By analyzing the distribution of capacitor current density and Joule heat, the thermal stress of the capacitor is mainly concentrated at the terminal connection and the busbar bend. The busbar thickness has a certain influence on stray inductance and surface loss. By reasonably selecting the busbar thickness, the stray inductance and surface loss can be reduced. With the increase of coolant flow rate, the maximum temperature of the capacitor core decreases significantly. When the flow rate is 0.05 m·s<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup>, the heat dissipation efficiency is the highest, and the maximum temperature of the capacitor core decreases by 53.9°C. Through the electrothermal and electromagnetic simulation and influencing factor analysis of the core-replaceable film capacitor, a certain reference can be provided for the design of new capacitors and the improvement of capacitor performance.