Based on the topology of the modular multilevel solid-state transformer with a common high-frequency bus

this paper constructs the distributed parameter equivalent model and analytical model for its interconnection channels. The impacts of distributed parameters

including leakage inductance

winding resistance

and equivalent resistance of switching devices

on the DC voltage and power transfer of the system are analyzed. On the premise of ensuring stable and reliable system performance

this paper further explores the reasonable range of distributed parameters that should be satisfied. With the transformer's power density and efficiency as the optimization goals

and the active power transfer ratio and temperature rise as constraints

an optimal design of the high-frequency transformer for the interconnection channel is conducted to meet the performance requirements. Additionally

equivalent thermal circuit models for the transformer and fins are established

and the heat dissipation design of the transformer is optimized with the objectives of light weight and strong heat dissipation capacity. Finally

a 50 kW/5 kHz transformer prototype is developed based on the optimization results

and experimental results verify the effectiveness of the transformer design proposed in this paper.