Adaptive Coordination Control among PV, Battery, and Methane Generation Unit

Abstract

Methane generation unit (MGU) can make use of power electricity and carbon dioxide to produce methane with the biocatalyst of methanogenic bacteria. In this paper, a simple external electrical characteristic model of MGU is constructed based on the accumulated experimental data and control variable method. Furthermore, the abovementioned model is applied in the islanded dc microgrid, and the adaptive coordination control strategy among photovoltaic (PV) generator, storage battery, MGU and local load is introduced based on dc bus voltage value. When in charging situation, the dc bus voltage will grow with the increase of the state-of-charge (SoC) of the battery, and the power consumption of MGU can adaptively increase with the increase of dc bus voltage. Because the much input power of MGU will produce hydrogen gas and suppress the activity of methanogens. Hence, the PV generator needs to limit its output power if the battery and MGU all work at their critical point. When in discharging situation, MGU needs to be cut out if the dc bus voltage drops to the setting value, then the battery will discharge to supply the local load till the next day.