Optimal selection of current control technique in multiphase DC-DC converters for dynamic load variations

Abstract

Multiphase DC-DC converters are widely adopted in high-power applications such as electric vehicles (EVs) and renewable energy systems due to their ability to reduce current ripple, improve efficiency, and distribute thermal stress across multiple phases. However, under dynamic load variations, mismatches in passive components, device parameters, parasitic elements, and thermal effects can result in phase current imbalance. This imbalance degrades transient performance, increases circulating currents, and reduces overall system reliability. Therefore, selecting an appropriate current control strategy is essential to ensure accurate current sharing and stable output voltage regulation under varying operating conditions. This paper presents a comparative study and selection methodology for current control techniques for MCU-based interleaved DC-DC converters. Various current control strategies are evaluated in terms of dynamic response, steady-state current sharing accuracy, implementation complexity, and embedded feasibility. A 1 kW, 36 V-12 V three-phase interleaved buck converter using Gallium Nitride devices is modeled in MATLAB/Simulink and validated through hardware experimentation. The comparative results highlight the trade-offs among transient performance, current balancing accuracy, scalability, and embedded implementation complexity, providing a structured basis for selecting an appropriate current control technique as per application requirements.