Design of Dry-type High-power High-frequency Transformer Based on Triangular Closed Core

High-power high-frequency transformer (HFT) is a key component in electrical energy routers. So far, the existing design of high-power HFT is mostly based on the single-phase double-winding transformer with the EE-type core or the C-type core. However, there is a lack of designs based on high-power HFT with other core types and multi-winding structures. An optimal design method for a 10kHz/250kVA dry-type natural-cooling HFT with six windings integrated based on the equilateral triangular closed nanocrystalline core is proposed. The core column specification is optimized based on the constraint between temperature rise and loss by traversing the width and thickness of the core column. In order to obtain the target inductance value, constraint between leakage inductance and the distance of main insulation is considered. The measured efficiency and the power density of the prototype are 99.76% and 4. 9kW/L, respectively. The maximum steady-state temperature rise of the prototype is 62. 65K, and the prototype has passed the insulation test. This work provides useful reference for the design and development of similar high-power HFT.