Maximizing Grid Forming Capabilities of Solar Inverters with Energy Storage Under Partial Shading Conditions

Grid-forming (GFM) solar inverters are often integrated with battery energy storage systems (BESSs) to regulate dc-link voltage and enable grid synchronization via dc-link voltage control. However, existing GFM solar inverters generally assume uniform irradiance conditions, overlooking the effects of partial shading conditions (PSCs). Under PSCs, photovoltaic (PV) operation may become trapped at a local maximum power point, which reduces PV power generation and imposes greater demands on the BESS, bringing it closer to its rated power. When operating at the limits of BESS hardware and PV generation, GFM capabilities are constrained, as transient power exchange exceeds the dc-side capacity. This paper presents a simple global maximum power point tracking method with an eventtriggered PV power-voltage curve scanning mechanism for GFM-controlled two-stage solar inverters integrated with a BESS. The proposed control strategy ensures maximum PV energy yield under all PSCs, allowing the battery to have sufficient margin for transient power exchange and maximizing the GFM capabilities of inverters. The control effectiveness is validated through simulation in MATLAB/Simulink. Index terms-Battery energy storage system, global maximum power point tracking (GMPPT), grid-forming converter, partial shading condition, photovoltaic (PV) system.
© 2025 IEEE