Hybrid Modulation and Control for Multi-Objective Optimized Active Power Decoupling Circuit in AC-to-DC Converter

Single-phase AC-DC power converters face the challenge of twice-grid frequency power ripple (TGFPR) caused by power imbalance, requiring the use of large DC-side capacitors. Active power decoupling circuits (APDC), typically buck, boost, or buck-boost converters, are commonly used in single-stage and two-stage AC-DC converters to address TGFPR. This paper presents a novel hybrid continuous and critical conduction mode (HyCCM) modulation technique for APDC used in single-stage and two-stage AC-DC converters to address the challenge of mitigating TGFPR. Unlike conventional soft-switching techniques, such as critical conduction mode (CrCM), which are limited in high-power applications due to increased conduction, winding, and core losses, proposed HyCCM technique optimizes efficiency without the need for additional circuitry. By dynamically transitioning between soft-switched CrCM and hard-switched continuous conduction mode (CCM) within a twice-fundamental cycle, the modulation strategy ensures optimal performance. Simulation and experimental results demonstrate significant improvements in efficiency over a wide operating range, making HyCCM a robust solution for APDC applications. Effectiveness of the proposed method is validated through analytical calculations and a laboratory prototype.