Design and Implementation of Transformer less UPS in Addition with Reactive Power Compensation for Industrial Application

An Uninterruptible Power Supply (UPS) is essential in providing reliable and efficient power to sensitive loads such as hospital life-saving infrastructure, telecommunication systems, and airplane computers. Regardless of the grid conditions, the UPS output remains closer to sinusoidal, making it more stable and reliable. Some other benefits of a UPS include minimum transient reaction time from grid mode to battery mode, almost unity power factor, high reliability, low cost, less weight, high efficiency, and good steady-state response time. The proposed UPS topology includes a bidirectional converter, a DC battery, a single-phase H-Bridge inverter, and an RL load with a diode bridge rectifier that acts as a non-linear load. The bidirectional converter helps to provide adjustable DC link voltage to supply the inverter and correction of power factor. During the power ON condition, the inverter functions as a reactive power compensator device, thereby enhancing the overall power factor of the system. In case of power CUT condition, the inverter provides sufficient power to the essential load, and the bi-directional converter functions as a buck converter during the ON condition of the supply and as a boost converter during the power cut condition of the supply. This configuration reduces the voltage drop across the transmission lines and improves the overall power factor of the system.