Design of high power LLC transformer based on magnetic integration technology

To address the challenges associated with the large quantity, considerable volume, and heavy weight of LLC transformers in rail vehicle power supplies, this paper presents a dual LLC transformer core integration solution tailored to the circuit characteristics. By incorporating a common decoupling post, the excitation inductance and leakage inductance parameters can be decoupled and adjusted, leading to the establishment of a novel integrated core structure. In line with the principle of minimal loss minimization, the thickness of the transformer's copper foil winding was optimized, and critical parameters such as core material and winding structure were determined. A 160 kW experimental prototype was successfully developed. The test results indicate that the integrated transformer is 18.8% smaller and 33.4% lighter than a traditional discrete solution. Both simulation and experimental results confirm the accuracy and engineering feasibility of this design approach.