As photovoltaic penetration increases across power grids, distributed energy systems must do more than simply convert sunlight to electricity—they must actively support grid stability through voltage regulation and reactive power injection. A comprehensive study presents a production-scale 91 kWp PV system coupled with lithium iron phosphate battery storage, engineered to deliver both energy and ancillary grid services simultaneously.
The system architecture employs three parallel boost stages for maximum power point tracking, feeding a 600 V DC bus that supplies independent bidirectional converters for battery management and a three-phase grid-tied inverter. Control is executed across multiple layers: cascade voltage-current loops regulate the DC stages, vector control with synchronous reference frame techniques manage the inverter output, and a supervisory algorithm coordinates MPPT, battery state-of-charge tracking, and reactive power generation according to grid voltage conditions.
Validation spanned five operational scenarios tested in both simulation and hardware-in-the-loop environments. Under rapid irradiance changes, the DC bus remained within 2.5% of its 600 V setpoint with transients settling in 80–100 milliseconds. During sustained voltage disturbances—both low (0.80–0.85 pu) and high (1.15–1.20 pu)—the system continuously redirected excess PV generation to battery charging while providing 78–80 kVAr of reactive support without violating current limits. Even with the battery fully charged, the system maintained stable operation through intelligent curtailment while expanding available reactive margin to 90 kVAr.
These results demonstrate that distributed PV-battery systems can serve as dynamic grid-support assets rather than passive generators. The architecture's ability to provide voltage support and reactive power simultaneously, while managing internal energy flows, positions it as a valuable model for future distribution networks managing high renewable penetration and demanding real-time voltage stability.
