Delay-dependent Stability Analysis of DC Microgrid with Distributed Control Considering Communication Delay

When designing a controller in DC Microgrid, normally the communication delay, which may cause system instability, has not been taken into account. In this paper, the effect of communication delay on system stability is studied based on a distributed control strategy. To obtain a less conservative condition for system stability, the delay-dependent stability is analyzed. In the case of time-invariant delays, the transcendental characteristic equation of the proposed Microgrid model is transformed into a Nyquist stability problem. Then the analytic solution for the system stability is derived while communication delay is, then the delay upper bound is given. Specially, the stability of time-varying is studied by using linear matrix inequality (LMI). Research shows that the proposed method provides a wider delay boundary, which makes the system safer, more reliable and stable. Finally, simulation and experimental results verify the effectiveness of the proposed stabilization methods.