The computational modeling of grid-connected double-chamber microbial fuel cell (DCMFC) bioenergy utilizing MATLAB Simulink software

Abstract

Owing to the depletion of fossil fuels, rising energy costs, and environmental pollution, there has been a growing focus on exploring and exploiting renewable energy sources. This study aims to demonstrate the modeling of a grid-connected double-chamber microbial fuel cell (DCMFC) biomass energy system via MATLAB Simulink software. The experimental measurements obtained from DCMFC outputs served as the basis for developing the inverter-grid connection model and simulation output in MATLAB Simulink software. Briefly, the DCMFC DC boost voltage was connected to the positive and negative buses of the three-phase DC‒AC inverter circuit, with switching patterns controlled by gate pulses in each transistor. Full square wave single-stage PWM pulses are generated by the gate for control. The power generated by the inverter was measured via a three-phase VI block for analysis, with voltages and currents displayed via a scope. To address potential noise during switching, an LC filter is employed to suppress noise output and stabilize power generation. Another power meter measures power from the grid, with waveforms displayed via scope blocks. Before synchronization between power from the DCMFC and the grid occurs, four requirements must be met: the grid voltage must match the inverter output voltage, the inverter frequency must match the grid frequency, the phase sequence must be the same, and the phase angle of the inverter must match that of the grid. Additionally, Institute of Electrical and Electronics Engineers (IEEE)-specific requirements were evaluated during the simulation for this study. In addition, this study critically examined whether the DCMFC inverter model conforms to conventional requirements, International Electrotechnical Commission (IEC) standards, and IEEE standards for the integration of inverters into the grid. Compared with previous studies on inverter modeling for grid connections, past studies have emphasized the efficacy of biomass power plants and different inverter topologies for photovoltaic (PV) systems. The current study focuses on optimizing a multilevel inverter-based model, achieving low total harmonic distortion (THD) below IEEE standards. In this study, the use of a multilevel inverter configuration proved highly effective in reducing the harmonic content, leading to synchronized phase sequences and enhanced coherence between the grid and inverter voltages. With a THD of 4.75% at 50 Hz, supported by a harmonic distortion value of 422.5, the chosen configuration significantly minimized the harmonic distortion. This success underpins the system’s reliability and efficiency, offering promising implications for practical applications.