Fast Simulation of Litz Wire Using Multilevel PEEC Method

Litz wire has been an essential component for the power electronic design to reduce the eddy loss. However, there is a lack of efficient numerical algorithms to simulate Litz wires due to their complex structures. This letter proposes a multilevel partial element equivalent circuit method that significantly improves the efficiency of the simulation of the Litz wire. This method boosts the simulation efficiency at both packing level and twisting level. In the packing level, a novel meshing method is proposed to capture the skin and the proximity effect accurately and efficiently. In the twisting level, the calculation is further divided into wire level and multipole level, where filament approximation and fast multipole method are unitized, respectively. Taking advantage of symmetry and memory replication, the proposed method is significantly faster and more economical than reported electromagnetic algorithms. The efficiency and accuracy of the proposed method are validated through comparison with popular toolkits and the measurement of two Litz wires with dozens and hundreds of wire strands, respectively.