Controlling DC microgrids in communities, buildings and data centers

Abstract

Microgrid technology is poised to transform the electricity industry. In the context of commercial/domestic buildings and data centers, where most loads are native direct current, DC microgrids are in fact a natural choice. Voltage stability and current/power-sharing between sources within a DC microgrid have been studied extensively in recent years. DC voltage droop control is known to have its drawbacks in that current or power-sharing is relatively poor. To eliminate this drawback, some have proposed to add a communication-based consensus control in addition to the primary voltage droop control loop. The current sharing performance is improved, however, the voltage deviation inherent in droop control requires a further, slower control to achieve voltage quality control. To overcome this complication, and reduction in response time, a low latency communication-based control technique that achieves proportional current sharing without significant voltage deviations is proposed in this work. The stability of the proposed control technique is compared to state-of-the-art using eigenvalue and transient analyses. The negative impact of communication delays on proposed control is discussed in detail.

Keywords

• eigenvalues and eigenfunctions
• quality control
• voltage control
• power generation control
• distributed power generation
• computer centres
• voltage stability
• current power-sharing
• dc voltage droop control
• communication-based consensus control
• primary voltage droop control loop
• current sharing performance
• voltage deviation
• voltage quality control
• low latency communication-based control technique
• proportional current sharing
• dc microgrids
• data centers
• developing countries
• renewable energy
• master-less control strategy
• energy source