Design, operation and control of a vast DC microgrid for integration of renewable energy sources

Abstract

DC Microgrid has been a key research area for the last few decades. The development of the DC microgrid system from renewable energy sources is necessary for future energy security for the country. Most of the renewable energy sources are intermittent. Power management and energy management are essential for the stable operation of the system and the high utilization of renewable sources respectively. Power management and energy management rely on the control of the different units of the DC microgrid. This paper presents an Islanded DCMG in which the PV system and the wind system connect with the DC bus through the interfacing devices (DC/DC boost and buck converters respectively) and their duty cycle is controlled by the P&O MPPT algorithm. Its power is fed to AC as well as DC load. DC load varies in steps and AC loads include single-phase linear, non-linear and three-phase inductive load. The sliding mode control technique is used to control the inverter connected to the DC bus to fed AC loads. DC bus voltage is supported by the hybrid energy storage system (HESS) (devices include Battery and Supercapacitor (SC)) with the use of active topology. Storage devices connect with the DC bus through the bidirectional buck-boost converters. A DC dump load is connected with the DC bus to stabilize the DC bus voltage and safety from the overcharging of the battery. The developed DC microgrid model is demonstrated in the MATLAB/Simulink. The results are presented, discussed and validated with the hardware experiment.