Single-Phase Single-Stage Multi-channel PV DC-AC Inverter and Independent MPPT Control Based on AC Power Ripple

As photovoltaic power generation increasingly shifts towards distributed and residential applications, it is exemplified by rooftop and balcony photovoltaic (PV) systems. This paper proposed a four-channel PV inverter between residential string inverters and microinverters using a DAB-based single-stage power conversion, with a novel ripple-based maximum power point tracking (MPPT) method. It leverages the inherent double line-frequency ripple of single-stage DC-AC converters to achieve or each channel using the ripple correlation control (RCC) method without additional ripple injection. The prototype adopts a simple topology and control method to achieve wide-range zero-voltage switching (ZVS) and low total harmonic distortion (THD) for grid current. Gallium nitride (GaN) and silicon carbide (SiC) devices are employed, along with an integrated magnetic design, aiming for higher efficiency and power density. The paper first reviews the current research, derives the topology, then modeling the converter and analyzed the converter characteristics. Subsequently, the principles of ripple based MPPT are analyzed, and the overall control block diagram of the circuit is presented. An 800W prototype is tested to verify the correctness of the aforementioned analysis. The prototype achieves a peak efficiency of 97.269% with a lowest grid current THD of 1.336% while enabling independent MPPT control across all four channels.