Analysis and design of planar inductor and transformer for resonant converter

With the increasing demand of low-profile, high-power density for power electronics system, the planar magnetics (inductors and transformers) begin to be adopted in many fields. The copper tracks on printed circuit board (PCB) are mostly adopted as the windings of the planar magnetics which cannot be changed flexibly once the PCB is produced. So the design method of planar magnetics is an important issue. In this paper, the Response Surface Method (RSM) is adopted to design the planar inductor. The method can exactly obtain the inductance and resistance by the formulas obtained from experimental or simulation test results which can simplifying the design process. For the planar transformer, the Modular Layer Model (MLM) is adopted to build the final equivalent model of the transformer, by which the magnetizing inductance, leakage inductance and resistance can be calculated. The proposed design methods of planar inductor and planar transformer are verified by a resonant converter prototype.