Large-disturbance Stability Analysis of DC Microgrid with Constant Power Load and its Transient Voltage Stability Control Strategy

Abstract

As the important part of future AC/DC hybrid distribution networks, maintaining the voltage stability of DC microgrid is very important for the safe operation of the distribution network. Based on Brayton-Moser's mixed potential theory, this paper first studies the large disturbance stability of a DC microgrid with constant power load. Then, the stability criterion of the analytic form of the system under large disturbance is obtained, which the effects of parameters such as AC side inductance, resistance, controller control parameters, and constant power load power values on the system stability are taken into account. According to the criterion, a stability control strategy for energy storage system is proposed. This strategy can avoid the unnecessary switching between the master and slave source, ensure the system stable under large disturbances and help the system quickly return to the stable state. The criterion and stability control strategy are simple and can be easily implemented. Simulation results demonstrate that the stability criterion and the control strategy are effective.