Distributed Event-Triggered Fixed-Time Secondary Voltage Control and Automatic Power Sharing for MTDC Grids

In this article, a novel distributed secondary voltage and active power-sharing control strategy with a Zeno-free event triggering mechanism is proposed, to overcome voltage deviation and inaccurate power-sharing caused by the conventional V-P droop control strategy in multiterminal high voltage direct current grids. The secondary controllers can achieve the voltage restoration and proportional active power sharing within a fixed time. Utilizing the Lyapunov method, the trigger function and trigger condition for the controllers of each voltage source converter (VSC) station are designed, resulting in a significant reduction in the number of controller triggers during system transients and steady state. The fixed-time stabilization theory is employed, which allows a faster convergence performance. Moreover, by using the tanh function, we can get rigorous proof of avoiding Zeno behavior. Finally, a simulation model of five connecting VSC stations is built to demonstrate the satisfactory performance of the proposed control strategy.