Modified Voltage Control Method for DC Distribution Networks by Coordinating PV Generation, Convertor Station and Energy Storage

DC distribution networks (DCDNs) have become a research hotspot due to low operation loss, high conversion efficiency, and flexible connection with DC renewable power generators (RPGs) and loads. However, considering the unpredictable fluctuations of the DC RPGs and loads, the bus voltage stability of the DCDNs should be given adequate attention. This paper proposes a modified voltage control method for DC distribution networks to address this critical issue by coordinating PV generation, convertor station, and energy storage unit. Firstly, the theoretical model of the medium-low voltage DCDNs is established, and the operating characteristics are analyzed. Then, various control modes based on the voltage deviation level are introduced, and the coordination control philosophy in different operation modes of the DCDNs is stated. Using MATLAB/SIMULINK, a detailed model of ±10 kV/750 V DCDNs simulation model is created, and simulations of different operation modes are performed to check the modified voltage control method’s efficacy. The results illustrate that the proposed control strategy can efficaciously guarantee the power balance, enhance the voltage stability of the DCDNs, and achieve smooth control switching to face various operating conditions. Therefore, the availability and feasibility of the modified voltage control method are demonstrated favorably.