Secondary Voltage Control of DC MG with Electric Vehicles and Hybrid Energy Storage Units: Disturbance Observer Approach

Abstract

In this article, the application of distributed second order consensus control framework is introduced for the hybrid storage devices. This controller helps to achieve coordinated power sharing among the 4-bus DC microgrid (MG) system through effective utilization of loads and plug in electric vehicles. The dynamics of the MG node affected by constant disturbances due to time-varying uncertain DC power loads which make the network highly heterogeneous. In this article, power reference in the V-P droop control scheme is modified using disturbance observer based leader follower control technique. The difference of total generation and total load of the system is considered as a disturbance using the proposed controller. In this, the control objectives can be achieved through primary and secondary control layers. Secondary level uses leader follower based consensus controller to mitigate the destructive effect and to restore the DC bus voltage in the presence of disturbance. This control strategy is compared with the existing controller to check the feasibility of the designed controller. An off grid DC microgrid with real time data of PV, wind and different kind of loads are chosen to examine the results in MATLAB and it shows that the proposed control scheme improves the system performance in a smarter way through information exchange.