A Partial-Winding-Excited Shunt Based Integrated Transformer With Single-Side Independent and Primary-Secondary Interleaved Hybrid Winding Structure

Integrating inductors and transformers is an important method to achieve high efficiency and high power density. Conventional magnetic integration schemes often face challenges such as limited leakage inductance adjustability, high winding loss, the need for specialized magnetic materials, and coupling of leakage and magnetizing inductances. This paper proposes a partial-winding-excited shunt based integrated transformer that enables decoupled inductances and interleaved winding structure, and the shunt is composed of ferrite and air gaps. The thickness and air gaps of the shunt can adjust leakage inductance, and the magnetic core air gap can adjust magnetizing inductance. By adopting interleaved windings, the winding AC resistance and winding losses can be effectively reduced. By exciting the shunt with a part of the primary independent windings, the required shunt reluctance for leakage inductance can be flexibly adjusted, allowing the optimal design of the shunt. A 500 W LLC resonant converter prototype is built to validate the integrated transformer. Experimental results show that the prototype has a peak efficiency of 97%. Through partial winding excitation and interleaved windings, the proposed magnetic integration scheme achieves the integration of inductors and transformers with high efficiency, good scalability, and manufacturability.