Improved Interleaved Layer Distribution for High-Frequency High-Power Planar Transformer

A key goal in the design of modern electromagnetic devices, such as transformers and filters, is the increase of the ratio between output power and volume or weight. This implies operating the device in the kHz range, as a mean for reducing the magnetic material of the core. Planar transformers are able to fulfil this goal, adding the benefits of modular assembly, which makes them specially well suited for building electric vehicle chargers, solar inverters, etc. Nevertheless, the operation at high frequencies and the small form factor of planar transformer is challenging, due to the increase of the leakage inductance and the parasitic capacitance. This paper presents the design of a 15 kW planar transformer, operating at 50 kHz. A novel, optimized layer interleaving schema is proposed for reducing its leakage inductance and its parasitic capacitance. The design is validated through numerical simulations with FEM commercial software.