On the Future of Micro Energy Control Unit (MECU) Integrated Grid

With promoting the application of renewable energy, distributed photovoltaic (PV) generation has become an important form of electrical source. More and more distributed PVs are connected into the power distribution system via traditional converters. With the continuous increase of PV penetration, the power grid is facing many challenges due to the inherent randomness and fluctuations of PV sources. Micro Energy Control Unit (MECU) is proposed as an alternative approach for the safe, economical, and efficient utilization of PV sources. Based on a multi-port structure, MECU connects photovoltaics, energy storage, the grid, and demand side loads. MECU can offer advantages of energy self-balancing, transient stability support, flexible demand-side integration, and power quality improvement. Two prototypes of MECU are developed for different application scenarios. Light-MECU is designed for small-capacity PV systems with strict space limits; The Modular Stackable Common-bus MECU (MSC-MECU) is used in high-power distributed PV grid-connected scenarios, such as rooftop PV systems. Experimental results show that MECU achieves energy self-balancing and transient stability support. MECU can be an effective solution for ensuring the reliable operation of power systems in the case of high PV penetration.