Integrated control strategy for smooth switching of the PV and battery-storage micro-grid based on operation state tracking

• Main Authors: Li Yang, Gao Song, Shi Wenhui, He Guoqing, Wang ZhengPing
• Format: Article
• Language: English
• Published: Wiley 2018-10-01
• Series: The Journal of Engineering
• Subjects: phase locked loops; invertors; power grids; energy storage; power generation control; distributed power generation; switching process; optical storage microgrid; improved control strategy; integrated control strategy; smooth switching; battery-storage microgrid; operation state tracking; main grid; grid-connected mode; islands mode; operation modes; AC bus voltage oscillation; improved energy storage inverter control method; operation states tracking; control variables mutation; improved software phase-locked method; grid phase state tracking; microgrid operation state control signal; operation mode changes
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.8877

Micro-grid which connects with the main grid can operate under the grid-connected mode or the islands mode. During the switching process between the two operation modes, if the control strategy is not complete, there will be problems such as the AC bus voltage oscillation and current surge, which will result in the switchover failure. An improved energy storage inverter control method based on operation states tracking is adopted for the optical storage micro-grid using master–slave control, which solves the problem of control variables mutation. Secondly, an improved software phase-locked method based on grid phase state tracking is proposed in an energy storage inverter. The problem of instantaneous mutation of the phase angle is solved by cooperating with the micro-grid operation state control signal during operation mode changes. Through the improvement of the two control strategies above, the transient shock phenomena of the micro-grid voltage and current during the switching process is obviously improved, and the harmonic content of the AC voltage and current is obviously reduced. Finally, a detailed model of optical storage micro-grid is established in MATLAB/Simulink, and the correctness and practicability of the improved control strategy are verified by simulation.