Design and HIL Testing of a Hybrid UPS with Seamless Transition

Rotating emergency generators (EG) have been increasingly installed to provide backup power in cases of blackouts. However, conventional rotating generators cannot provide fast pickup of load as soon as a blackout is detected. The paper presents a hybrid UPS system based on a battery energy storage system (BESS) and a rotating EG that can provide Class 2 response to the load during the power transfers between the load and the utility as per the Japanese standard on UPS JEC2433-2016. The same idea is also shown to work for cost savings by switching to backup power for areas with multi-part or time-of-use tariffs. The design process including controller hardware in the loop (CHIL) testing with real time simulators is also presented as it makes the design process more efficient. The process was used to test compliance with JEC2433-2016 in addition to speeding up the controller validation and testing step in the product design and development cycle. The proposed hybrid UPS is validated using CHIL and hardware testing.