Modeling and Calculation of Core Loss and Heat Distribution in Ultra-Thin Wound Core Reactor Based on Electromagnetic and Fluid-Thermal Coupling

The anode saturable reactor (ASR) is a critical component in converter valves for protecting thyristors. In recent years, fault issues caused by abnormal heating have received widespread attention. However, the complex structure of the ASR presents a significant challenge for accurate temperature rise calculations. This study focuses on a electric trigger thyristor (ETT)-type ASR and establishes a comprehensive electromagnetic-thermal-flow simulation model. The improved Bertotti loss separation model is applied to calculate core losses, and time-averaged losses are used as the heat source coupled to the temperature field to address the mismatch between the time scales of losses and temperature rise. The temperature distribution of multiple core pairs in the ASR is solved based on a fluid-thermal coupling method and compared with three other methods. Experimental results show that under normal operating conditions, the core temperature of the ASR is approximately $75~^{\circ }$ C, with slight temperature differences observed across the cores. The proposed heat calculation model provides more accurate results than other models.