A Novel Peer-to-Peer Control Strategy for Multiterminal DC Distribution Systems

This paper proposes a novel peer-to-peer control strategy (PPCS) and then develops a generalized hierarchical control scheme (GHCS) based on the PPCS for DC voltage control and power sharing in multi-terminal DC distribution systems (MTDCDSs). At the primary level of the GHCS, the combination of the designed integration and deviation adjustment equation (IDAE) controllers, the ReLU-based standby controllers, and the peer-to-peer structure is developed to implement the PPCS. With the PPCS, not only is the mode switching of the voltage source converter (VSC) eliminated when the system’s operating conditions are changed, but also three objectives, including minimizing DC bus voltage deviation, achieving precise power sharing, and ensuring a fast dynamic response, are achieved at the same time. At the secondary control level, a simple optimization algorithm for voltage distribution and line losses is developed. The constrained optimization of the proposed GHCS does not require the consideration of the local controller’s structure because all voltage source converters with the PPCS perform constant power tracking control. As a result, the GHCS is simple and easy to implement. The optimal operation and satisfactory performance of the GHCS-controlled MTDCDS are demonstrated theoretically and validated through hardware-in-the-loop (HIL) tests in a ±10 kV MTDCDS.