A reliable photovoltaic integrated UPS system with modified maximum power point tracking (MPPT) algorithm

This paper presents a new approach to integrate a fluctuating renewable power source like PV array into a conventional UPS by only modifying existing UPS firmware without needing any additional power converter. The paper also presents PV-UPS integrated system simulation developed using MATLAB/SIMULINK and hardware testing results for a 550kVA UPS interfaced with 30kW of solar panels. Proposed solution is modular, scalable, can work together with existing conventional UPSs on site or even upgrade them to interface PV power and still be as reliable as a conventional UPS. The proposed solution will allow utilities to do peak shaving and will help customers to reduce energy bills and extend battery time while providing same excellent power quality as conventional UPS. Unlike PV inverters which are forced to go offline during utility outage, proposed system shall continue to support critical loads during outages which is especially important for areas where utility interruptions are common.