Real-Time Inverter Supervisory Hardware for Distributed Renewable Energy

The inverter supervisory board was designed to operate as the central control element in photovoltaic systems connected to weak electrical grids, where high solar penetration may trigger instability on the AC bus. Its primary function is to continuously monitor the real-time power flow between the load, the grid, auxiliary generators, and the photovoltaic inverter, ensuring that the system remains within safe operating limits. To achieve this, the board directly measures the three-phase grid voltages and load currents, from which it calculates the instantaneous load power. The power delivered by the inverter is obtained through MODBUS communication over one of the RS-485 interfaces, allowing the controller to accurately reconstruct the system’s full power balance. With these measurements, the board derives the effective contribution from the grid or generator, enabling rapid detection of over-injection, reverse power flow, or insufficient load conditions.

Fig.1 — Hardware developed

Engineered for robustness and flexibility, the board includes auxiliary digital inputs, dual RS-485 interfaces, an integrated 127/220 V AC supply input, full three-phase voltage and current measurement channels, an auxiliary 12 V DC output, and two NO/NC relay outputs for external control. Its signal-conditioning chain is designed to ensure stable and high-fidelity measurements even under rapid fluctuations typical of weak-grid environments. Using this data, the embedded firmware performs continuous checks and, when required, sends commands to the inverter to limit photovoltaic power injection, preventing oscillations and enhancing grid stability. In doing so, the supervisory board becomes a key element in coordinated renewable-energy integration, ensuring that solar generation operates reliably, predictably, and in accordance with the real conditions of the electrical installation.

Fig.2 — Product installed in the field