Adaptive primary droop control for islanded operation of hybrid AC–DC MGs

Abstract

This study is dedicated to establish an adaptive primary droop control of interlinking converter (IC) for the islanded operation of hybrid AC–DC microgrids (MGs). In this practise, the amount of transferred power through the IC is controlled such that all of the resources in both AC and DC MGs are in equal loading per cents. To do so, two different notions are contemplated. In the first one, the IC is controlled such that the aforementioned control objective is satisfied for all possible values of transmission lines impedance angles. To this end, a new algorithm is developed within which the IC estimates the impedance angle based on the local measurements in AC MG and then adapts itself. In the second outlook, the uncertainties in association with the renewable energy resources are considered and their effects are explored on IC performance. To lessen the negative impacts of uncertainties and fluctuating power generation of renewable resources, the control of IC is updated based on the instantaneous power generation in AC and DC MGs. Accordingly, the main control objective is effectively pursued. Performance of the proposed adaptive droop control is evaluated on a test MG. Results are discussed in depth.