A-φ method was used for eddy current field analysis, and based on magnetic circuit analysis and Faraday law of electromagnetic induction, coupled field-circuit equation was derived, which was expressed by magnetic vector potential A and the parameters of the equivalent circuit. 采用复矢量磁位-复标量位(A-φ)法计算涡流场,同时基于磁场分析和法拉第电磁感应定律得出了矢量磁位(A)与等效电路参数的耦合方程。