The output power of each photovoltaic module varies under different illumination and temperature conditions. Therefore

when some PV panels are shaded

the H-bridge modules with higher power generation will face the risk of over-modulation due to their narrow operational range

which significantly reduces the solar energy utilization efficiency of the inverter. To address the limitation that traditional strategies can only expand the operational range of H-bridges to a limited extent

a strategy of cascading batteries on the PV side was proposed. By cascading batteries on the PV side

a cascaded H-bridge PV grid-connected inverter integrated with battery units was constructed. On the basis of the maximum modulation index of H-bridges and the state of charge of batteries

the inverter was divided into five operational modes. When the modulation index exceeds 4/π

the battery is adjusted to the discharge state to serve as an additional energy source

which reduces the modulation index of units with higher power generation and thus expands the operational range of H-bridges. Experimental results verify that this strategy enables the inverter to break through the traditional constraint of a modulation index below 4/π

maintain maximum power point tracking operation even under extreme conditions

and exhibits superior grid-connected stability.