Design-Oriented Modeling and Multi-Objective Optimization of Two-Phase Coupled Inductors in Multiphase PWM Converters

Two-phase coupled inductors can achieve the same steady-state inductance as two discrete inductors with reduced core volume and improved dynamic response, which makes them advantageous in interleaved multiphase PWM converters. However, there is currently no comprehensive and systematic optimization method for two-phase coupled inductors to determine the optimal core dimensions for given design targets. To fill this gap, this paper proposes a design-oriented magnetic circuit model for two-phase coupled inductors based on common-mode and differential-mode decomposition, which offers more physical insights for core geometry design compared to conventional flux analysis. The design of a two-phase coupled inductor is then formulated as a multi-objective optimization problem, aiming to minimize overall volume, power loss, and transient inductance while meeting requirements on steady-state inductance, form factor, and saturation current. The proposed design-oriented model and multi-objective optimization method are validated through comparisons with Monte Carlo simulations using ANSYS and experimental hardware results.