Control of buck and boost converters for stand-alone DC microgrids

Abstract

This paper presents the modelling and control of Buck and Boost converters to be operated in a stand-alone DC Microgrid. The Buck and Boost converters can be considered as the basis of a number of other converters, therefore the control system presented can be extended to other similar applications. The two converters can be used to interface photovoltaic (PV) panels or wind turbine systems to a DC microgrid. In this paper both converters will be modelled in continuous conduction mode (CCM), and the control system needed to operate these converters in a stand-alone DC microgrid will be presented. The inductor current and the output voltage of the converter will be controlled using nested control loops. The droop control method will be utilized to obtain load sharing between the converters when these are paralleled in the microgrid. An outer addition voltage restoration loop will be applied to restore the desired voltage in the dc microgrid, correcting any voltage deviations caused by the droop control method. The operation of the control loops will be tested by simulations. The simulation model will consist of two paralleled Buck converters operated in CCM, while sharing a common resistive load.