Unbalanced Voltage Suppression of Bipolar DC Microgrids with Integration of DC Zero-Carbon Buildings

Considering the majority of electrical equipment utilized in society is driven by DC, integrating a DC system can significantly enhance the efficiency and reliability of power systems by implementing the integration of diverse loads, renewable energy sources (RESs), and energy storage systems (ESSs). In this paper, the integration of multiple DC zero-carbon buildings (DC-ZCBs) is proposed to achieve the unbalanced voltage suppression of the bipolar DC microgrid (DCMG). The photo-voltaic (PV) technology, loads, and DC electric springs (DC-ESs) are adopted as a unified entity to achieve the zero-carbon emission of the building. Firstly, a new configuration of PV and DC-ESs is introduced. The energy management of PV, ESS, and load are fully considered in this new configuration, which can reduce the capacity of the ESS. Subsequently, a distributed co-operative control strategy for DC-ESs based on the modulus voltage is presented, which is implemented with integration of the new configuration into the bipolar DCMG. The proposed approach addresses the issues of unbalanced voltage to improve the operating efficiency and power quality of the bipolar DC-MG. The simulation is conducted in MATLAB/Simulink platform to confirm the effectiveness of the proposed approach.