A Control Strategy for Multiterminal DC Grids With Renewable Production and Storage Devices

This paper provides a solution for the control of multiterminal dc networks from the point of view of the network's transmission system operator, which includes local, primary, and secondary controllers. A new power flow technique is validated for this approach, which guarantees the stability and requires fewer calculations than the conventional techniques. This study also describes an optimal control strategy for intermittent (renewable) energy producers, where the controller periodically transmits information about its state to the system operator. Its main goal is to optimize economic profit for the producer. This last controller is implemented via model predictive control. The whole control strategy is validated in a scaled dc grid test-bench with four nodes. Real solar production (5 kW rated power), a storage system, as well as short-term weather and consumption forecasts are also included.