Stabilisation and transient performance improvement of DC MGs with CPLs: non-linear reset control approach

The stabilisation and transient performance improvement of a non-linear direct current (DC) microgrid (MG) dynamic which is controlled by a power buffer is studied. The injecting current of the power buffer is designed based on a novel reset gain-scheduling controller. This controller is constructed via a polytopic linear parameter varying-based dynamic controller that is equipped with the resetting action. The dynamic controller theoretically assures the closed-loop stability of the DC MG through the continuous-time Lyapunov theory. Also, the resetting action enhances the transient performance. The sufficient conditions of the controller design are derived in terms of linear matrix inequality and are solved by convex numerical methods. Comparing with the existing results, the proposed hybrid approach provides a non-continuous current reference of the power buffer, which efficiently improves the transient performance. To show the merits of the proposed approach, it is applied to a non-linear DC MG feeding one constant power load (CPL). Results show the simplicity of designing the proposed controller and the settling time and overshoot of the DC bus voltage compared to the state-of-the-art methods. Also, software-in-the-loop simulations are presented to prove the practical applicability of the proposed controller.