Delay-Dependent Stability Evaluation for Temperature Control Load Participating in Load Frequency Control of Microgrid

Temperature control load (TCL) usually participates in load frequency control of microgrid (MGLFC) through open communication network, which inevitably introduces time delays. Time delays will degrade the performance of MG and even lead to instability. In this article, the delay-dependent stability for MGLFC with TCL participation is evaluated. First, a model of TCL participating in MGLFC is constructed with time delay induced by open communication network and transformed into a time-delay system. Then, the delay-dependent stability for MGLFC with TCL participation is evaluated by the Lyapunov stability theory. The stability evaluation criterion obtained is less conservative and can provide a larger stability margin of time-varying delay for MGLFC with TCL participation. Finally, the effectiveness of the model and the advantages of the proposed method are verified by numerical calculation, simulation tests, and experiments. The results indicate that, compared with the existing methods, the proposed criterion can obtain a larger delay margin without increasing the computational complexity under the same controller gains. In addition, with the participation of TCL, MGLFC performs a larger time-delay tolerance and can well resist the negative effects of time delays.