Passivity-Based Control of DC-DC Boost Power Converter for MPPT used in DC Microgrid Systems

DC microgrid systems can operate in both; islanded mode or grid-connected mode through a common DC bus, where the photovoltaic (PV) array supplying power to the DC bus by means of the dc-dc boost power converter. In grid-connected mode, the DC-bus voltage is kept constant by grid-connected control-loop using dc-ac power converter. To this end, the input voltage of the dc-dc boost power converter must be controlled so as to impose the operating point of the PV array provided by the maximum power point tracking (MPPT) algorithm. Thus, this paper presents a robust nonlinear control strategy using passivity-based control (PBC) to track a reference voltage provided by the MPPT algorithm of the dc-dc boost power converter used in DC microgrid systems. Based on the energy shaping and the damping injection technique, the PBC strategy provides a property of energy dissipation as well as robust voltage control. This control strategy ensures large signal stability as well as fast recovery performance of the system during irradiance changes. MATLAB simulation and OPAL-RT real time simulator results are presented to verify the control performance of the proposed control strategy.