State of the art review of uninterruptible power supply technologies including design control methods and critical applications

Uninterruptible Power Supply systems are vital for ensuring continuous, high-quality power delivery in critical applications ranging from data centers to industrial automation and healthcare facilities. This paper presents a comprehensive assessment of the state-of-the-art in UPS technologies, focusing on their design architectures, advanced control schemes that enhance voltage regulation, frequency stability, power quality, and battery lifecycle management and their diverse applications. The study also examines power sharing, redundancy management, and emerging trends such as grid integration and renewable energy support. Through an in-depth review of recent literature and technological advancements, this paper provides insights into the evolution and future direction of UPS, aiming to guide both researchers and practitioners in developing more efficient, intelligent, and reliable power backup solutions.