Coordinated Power Control Strategy of PV Inverters and VSCs in DC-Interconnected Low-Voltage Distribution Networks

The integration of high-proportion photovoltaics (PVs) introduces numerous challenges for low-voltage distribution networks (LVDNs), including overvoltage, undervoltage, high power losses, and reverse power flow. Addressing these issues through flexible devices and DC-interconnection technology has become a trend due to their large transfer capacity and flexible power regulation capabilities. This paper proposes a coordinated control strategy and parameter design for PV inverters (PVIs) and voltage source converters (VSCs) in DC-interconnected LVDNs. An improved VSC power control strategy is introduced, which incorporates switching of control modes among interconnected VSCs facilitated by weak communication signals, with regulation power determined through local droop control. Additionally, a systematic parameter optimization method for PVIs and VSCs is developed, aiming to minimize network losses by ensuring effective voltage control and reducing redundant regulation. The proposed methods are validated through simulations on a practical distribution network, demonstrating significant improvements in voltage regulation and a reduction in power losses. The results highlight the effectiveness of the proposed strategies in enhancing the reliability and efficiency of LVDNs under varying network conditions.