Automatic phase selection devices: analysis and development prospects

This paper analyzes automatic phase selection devices (APSD) used to ensure reliable power supply for single-phase consumers in three-phase electrical networks. Existing devices are classified into digital and analog types, and their schematic structures, operating principles, and application areas are examined. The results show that while digital APSDs provide higher accuracy and adaptability, they have a more complex structure and higher cost. Analog devices are simpler and cheaper but cannot effectively mitigate voltage unbalance in modern grids. Currently, due to the large-scale integration of single-phase photovoltaic (PV) inverters into the grid, the issue of voltage unbalance has become more pressing. Therefore, this paper proposes the development of a new generation of APSDs capable of calculating the unbalance factor, automatically selecting the optimal phase, and performing real-time monitoring.