Study of Battery Energy Storage Operation in Droop-Controlled Residential DC Nanogrid

Conventional AC systems offer a straightforward, adaptable, and reliable electrification solution for residential buildings. However, this simplicity has several drawbacks when utilizing renewables, such as decreased efficiency due to additional conversion stages, load imbalance in multiphase systems, harmonics, and improper energy balance. A DC-based approach could be used instead of the AC in residential nanogrids (NGs). For a residential NG, DC systems can eliminate those DC-AC conversion stages by only relying on one grid-side active front-end converter. Additionally, using DC droop control, the stable operation of a DC NG can be achieved without extra communication between converters sharing the DC bus. The paper focuses on simulating the operation of a droop-controlled residential DC NG for the case of maximum self-consumption and the resulting battery degradation. The simulation used a J-minute temporal average, actual generation, and consumption data from an Estonian dwelling. In addition, the simulation considers the economic aspects of the system and battery reliability assessment using simulated data.