Design of Composite Repetitive Controller for Single-Phase Uninterruptible Power Supply Inverter Circuit

Abstract: Single-phase uninterruptible power supply (UPS) is widely used in all kinds of important electrical equipment to ensure the smooth implementation of power supply. The core part of the UPS is the inverter circuit, and the control of the output voltage of the inverter circuit is of great significance. This paper takes the single-phase fullbridge inverter circuit as the research object. First, the mathematical model of the system is obtained based on the frequency domain modeling method of the minimum phase system. Then, a composite controller composed of an inverse system and repetitive control is proposed. By expanding the repetitive controller transfer function, the inherent positive feedback term of the repetitive controller is found, and the inherent positive feedback term is overcome by a parallel proportional term. Using frequency domain analysis, the design process and parameter selection method of the complex repetitive controller are given. Finally, the effectiveness of the proposed control method is verified by experiments. When the inverter system is connected to the resistive load, the instantaneous output voltage error fluctuates within ±0.30 V and the total harmonic distortion rate is 1.28%. Compared with the traditional cascade control, the output voltage error fluctuates within ±1.10 V and the total harmonic distortion rate is 2.98%. The performance of the proposed control method is greatly improved, which indicates the engineering application value of the proposed inverter control scheme.Cite this article as: Y. Gangfeng and K. Xi, "Design of composite repetitive controller for single-phase uninterruptible power supply inverter circuit," Electrica, 25,0099, 2025. doi: 10.5152/electrica.2025.24099.