An integrated grid-connected system for multi-port energy processing by microcontroller

The requirement for converters to process different kinds of energy has been urgent. Developing new type of power converter to deal with multi-port energy therefore becomes much more important than before. In this paper a multi-port single-stage converter (MPSSC) is proposed, which is an integrated system (IS) and can handle power direction among battery bank, AC mains and LED load. Even though the MPSSC processes three ports, its main power stage is a single-stage configuration instead of the combination of multiple converters. That is, it can process power effectively and more easily comply with industry standards. The MPSSC is mainly derived from a single-ended primary-inductance converter (SEPIC) incorporating interleaved structure. While the MPSSC draws energy from utility to charge battery bank and/or powers DC load, it is able to perform power factor correction (PFC) over universal line input. In the case of power failure, the MPSSC can instantaneously change energy direction and then discharges the battery so as to power load consecutively. The integrated system of MPSSC is analyzed theoretically. In addition, a 200-W microcontroller-based prototype is built to validate the converter with practical measurements.