Intelligent control technology is gradually becoming a key force to promote the performance improvement of electrical engineering systems. In this paper, for the nonlinear system with serious state time lag, vector Lyapunov function is constructed to relax the traditional single-function constraints and realize the flexible analysis of the stability of multiple subsystems. According to the current tracking requirement of MMMC converter, the Lyapunov controller is designed to realize the current stability control. Combined with the segmented linear approximation method, the complex nonlinear functions are decomposed into multi-domain linear combinations to reduce the complexity of controller design. The results show that the Lyapunov function can balance the convergence speed and convergence stability when the controller parameters α are taken as 0.95 and β is taken as 2. Under the influence of external event triggering mechanism, the nonlinear system equilibrium point of Lyapunov function controller remains asymptotically stable after 5s. Under the influence of faults, the trajectory of the system controlled based on the Lyapunov function controller can still return to the stability domain.
