Sensor-Reduced Control Based on Unknown Input Observer for Single-Phase Inverter

To improve the adaptability of single-phase inverters under different load conditions, this paper proposes a sensor-reduced control strategy based on unknown input observer (UIO). Under the assumption that the load current is bounded with known upper and lower bounds, the algebraic relationship between the capacitor voltage and load current is constructed by designing an interval observer. Furthermore, based on this relationship, a UIO is designed to realize the online estimation of inductor current and load current. Compared to existing control methods, the proposed scheme requires only the output voltage signal for sensing, effectively ensuring stable operation of the inverter under different load conditions while reducing system costs and improving reliability. Finally, simulation results verify the feasibility of the proposed approach.