Parallel operation of distributed power converters is used to realize high rated power and low current ripples with low rated power devices. It is also being preferred since central compensators fail to identify power quality problems reflected on low voltage levels, especially with the new structure of microgrids. This paper proposes a novel parallel operation between modularized distributed transformerless unified power quality conditioner (TL-UPQC) for low voltage distribution networks. The operation is intended to improve the grid voltage profile while considering the connected modules rated capacity. The proposed methodology is suitable for smart grid applications where multiple renewable energy sources are integrated with the network. An advanced control technique that allows monitoring, wireless communication and coordination between the connected modules is presented. The proposed control methodology allows modularity and operation flexibility. System characterization has been studied to evaluate the influences of communication delays on overall system stability. The system has been evaluated by controller hardware-in-the-loop testing methodology. The power stage is simulated in a real time digital simulator, while the control algorithm is developed in a digital signal processor. Experimental results including random behavior of a photovoltaic system are presented.
R. M. Abdalaal and C. N. M. Ho, "Analysis and Validations of Modularized Distributed TL-UPQC Systems with Supervisory Remote Management System," in IEEE Transactions on Smart Grid, doi: 10.1109/TSG.2020.3044992.
KEYWORDS: D-STATCOM, hardware-in-the-loop, hierarchical control, parallel operation, power quality, UPQC, smart grid, voltage regulation, wireless communication