Coordinated Control of an Islanded Microintegrated Energy System with an Electrolyzer and Micro-Gas Turbine

Abstract

Microintegrated energy systems (MIESs) can be disconnected from power distribution systems during power system faults. This paper develops a control scheme for an islanded MIES. The VSC inverter controls the AC bus voltage and frequency using a modified AC voltage regulator and a modified frequency regulator. The control structures of the power-to-gas and PMSG-based microturbine generator (MTG) systems are improved. Renewable generation always runs at the maximum power point. The surplus renewable energy in the MIES can be converted into natural gas using power-to-gas, and the MIES can make full use of renewable energy. The proposed coordinated control scheme of the electrolyzer and the supercapacitor can achieve a power balance of the islanded MIES and reduce the DC-link voltage fluctuation. A micro-gas turbine can provide electric energy to the load and enhance distribution system resilience. A coordinated control scheme of the MTG and the supercapacitor is developed to improve MIES operation. A feature of this paper is the research on fault ride-through of the islanded MIES. A fault ride-through strategy is proposed, where the AC voltage of the VSC inverter is reduced to limit the short-circuit current during AC system faults. Islanded MIES simulations are conducted in a MATLAB/Simulink environment to test the control scheme. The simulation results verify the effectiveness of the control scheme during normal operation and failure.