Unified Model of Peak Current Mode Controlled Coupled SIDO Converters

Abstract

Coupled inductor single-input–dual-output (CI-SIDO) converters are promising converters used in the applications that demand multiple voltage supplies due to their high efficiency and small volume. However, this class of converters suffers from poor cross-coupling and cross-regulation issues, which affects the dynamic performance and stability. These issues can be suppressed with peak current mode control because of its faster dynamic response. To design the controller and study dynamic performance, a small-signal model of the system is essential, which consists of a converter model and current modulator model. However, developing the current modulator model for PCM controlled CI-SIDO converters is challenging because it consists of two reference current for two inductor currents each consisting of three slopes. No literature is available that derives a unified model of PCM controlled CI-SIDO converters. Therefore, this article proposes a unified small-signal model for PCM controlled CI-SIDO converters. The proposed model is applicable to three topologies of CI-SIDO converters, i.e., CI-SIDO buck, CI-SIDO boost, CI-SIDO boost and buck converter. The proposed unified model is a useful tool to study the dynamic performances, stability, and design outer controllers. Finally, the accuracy of the proposed unified model is verified by performing simulation and experiment of PCM controlled CI-SIDO converters considering inner-loops closed.