A Current Ripple Driven Design Methodology for Filter Inductors in Dynamic Power Converters Using Adaptive Delta-Sigma Modulation

This paper introduces a design methodology for filter inductors in dynamic power converters using adaptive asynchronous delta-sigma modulation (ADSM). Filter inductors account for a significant proportion of the volume in such converters. Given a specified current ripple amplitude, this paper presents a design methodology for power filter inductors, based on the finding that the current ripple under ADSM is constant. Further using adaptive ADSM, the method can be used to optimize the inductor size, peak current ripple and switching frequency range while maintaining constant switching losses. It is demonstrated that with equivalent setups, the inductor value using adaptive ADSM is reduced by 36% for the same maximum current ripple and switching losses compared to PWM, while the peak current ripple is reduced by 53% compared to ADSM.