Electrical Modeling and Control of Microbial Electrochemical Systems for Naval Applications
Abstract
Electrical Modeling and Control for Microbial Electrochemical Systems The goal of this proposal is to investigate the interactions between microbial electrochemical activities and the electrical harvesting systems in microbial fuel cell (MFC) related reactor platforms to develop engineering solutions for practical electrical energy production and utilization. Significant progress has been made through microbiological and electrochemical advancements in terms of possible power generation in W/m2. However, extracting the most practically possible power or energy out of the theoretical potential in MFC requires a totally different perspective. For example, connecting a resistor as a load can surely show the generated power, but there is zero usable power because all is burned up in the resistor. It is well known that the maximum power can be obtained at the point where the external resistance is same with internal, but an actual load cannot be a simple fixed-value resistor because the load current may vary. Charge pumps have been widely used at the output port of the benthic and sediment MFCs, but charge pumps control the output, not the input (i.e., MFC output voltage); this entails in non-maximumpower operation which has quite inferior efficiency and controllability. Furthermore, MFCs are difficult to scale-up by just physically connecting multiple reactors. Therefore, advanced power electronics converters are inevitable to use for practical applications, but it has never been investigated how their pulse-type power extraction affects the microbial community, especially in longer-term operations. We believe that a different approach from the electrical side of MFC systems is necessary to develop an appropriate framework to define them as complete microbial-electrical energy system. A better understanding of the MFC system from the electrical aspect is crucial, especially on how the two different systems interface each other and how electrical control works on the other side. As well as the bioelectrochemical technologies, electrical engineering insight and techniques can now be useful. This will push the MFC technology to the next level in terms of controllability, efficiency, and sustainability, and in turn improve the MFC’s contribution to naval missions with improved functions such as higher power generation, faster recharge, and longer operation time. In this project, we propose to develop a new MFC energy system model that for the first time focuses on the electrical interface and control of microbiological and electrochemical mechanisms. For the foundation of the project, electrical demand of naval applications and electrical capacity of MFC system will be analyzed. An expanded system model including electrical controller will be developed by defining controllable and observable variables. We will apply electrical engineering techniques such as transfer function synthesis and time- and frequency-domain analysis. Based on the developed model, real-time control algorithms that can optimize instantaneous power extraction and longer-term energy harvesting will be developed. It is well known that the MFC system is an electrically capacitive system, hence we will investigate if the resonant impedance matching technique can substantially decrease the resistance and enable higher power extraction and more efficient energy harvesting. Furthermore, urgent challenges such as scaling up MFC systems and autonomous start-up will be addressed. The research team is a leading group in MFC energy harvesting and the first demonstrated the new “active harvesting” concept, which shows significantly increase in MFC’s power output and improve dynamic controllability of MFC output. The team consists of expertise in electrical and environmental engineering, and capable of conducting the proposed interdisciplinary research.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512570
Entities
People
- Jae-Do Park
Organizations
- Office of Naval Research
- Regents of the University of Colorado
- United States Navy