A Modified PV to Virtual Bus Parallel Differential Power Processing Architecture for Photovoltaic Systems

Abstract

This paper proposes a simplified parallel differential power processing (PDPP) architecture for photovoltaic (PV) systems that reduces hardware complexity by eliminating one dual active bridge (DAB) converter and one intermediate bus capacitor from the previously introduced PV2VB PDPP two-string architecture. In the reference PV2VB PDPP architecture, each PV string is interfaced with its own string-level converter (SLC), comprising a DAB and a bridgeless (BL) converter, for maximum power point tracking (MPPT) and differential power exchange via a shared virtual bus. The proposed topology maintains the use of bridgeless converters for each PV string but replaces the two DAB stages with a single dual-bridge DAB converter, which connects one intermediate bus on one side and the virtual bus on the other. This approach maintains isolation and bidirectional power flow, while significantly reducing the number of magnetic components, switches, and control loops. Simulation results demonstrate that the system can reach and sustain steady-state operation of the virtual bus under various mismatch conditions, validating the effectiveness of the proposed architecture in ensuring power balance and enabling string-level MPPT. The results suggest that the proposed scheme preserves the key benefits of the PV2VB PDPP framework, while simultaneously reducing overall system cost.