An On-Line Uninterruptible Power Supply with High Input Power Factor

On-line uninterruptible power supplies are widely used account of the high quality of the output voltage and high performance. This type of uninterruptible power supplies is used for power supply of systems requiring high voltage quality and uninterrupted power supply. The article presents the topology of an on-line uninterruptible power supply system providing an input power factor of 0.99. The developed system provides operate on linear and nonlinear loads (crest factor 3). The paper describes the system of an online uninterruptible power supply and the analytical expressions for determining the main parameters of the system. The proposed system consists of three converters: an input converter (AC-DC), an output converter (DC-AC) and a charge-discharge converter (DC-DC). The charge-discharge converter ensures the operation of the system from the battery, which is a buffer power source, when the input three-phase electrical grid is disconnected. The developed topology provides galvanic isolation of power sources from the load. For confirming the operability of the developed on-line uninterruptible power supply, the results of simulation modeling of the system in various operating conditions under nonlinear load, which is the worst condition for the system operation, are presented. The simulation was performed in the software package PSIM 2022.1 with closed-loop automatic control systems. The article is an overview of the developed online uninterruptible power supply topology, the synthesis of the automatic control system will be given in the following operates.