Skip to main content
Navigate Up
Sign In
 

Publication Abstracts

Jae-Do Park, Ph.D


Jae-Do Park, Zhiyong Ren 
Energy Harvesting System for Microbial Fuel Cells with Maximum Power Point and Parallel Operation Capability 
IEEE Transactions on Energy Conversion, In press, doi:10.1109/TEC.2012.2196044 
[ Full Text ]

Microbial fuel cell (MFC) is an emerging technology for sustainable energy production. An MFC employs indigenous microorganisms as biocatalysts and can theoretically convert any biodegradable substrate into electricity, making the technology a viable solution for sustainable waste treatment or autonomous power supply. However, the electric energy currently generated from MFCs is not directly usable due to the low voltage and current output. Moreover, the output power can fluctuate significantly according to the operating conditions, which makes stable harvest of energy difficult. This paper presents an MFC energy harvesting scheme using a hysteresis controller and two layers of DC/DC converters. The proposed energy harvesting system can capture the energy from multiple MFCs at individually controlled operating point and at the same time form the energy into a usable shape. 


Heming Wang*, Jae-Do Park, Zhiyong Ren 
Active Energy Harvesting from Microbial Fuel Cells at the Maximum Power Point without Using Resistors 
Environmental Science and Technology, In press, doi:10.1021/es300313d 
[ Full Text ]

Microbial fuel cell (MFC) is a new approach to accomplish simultaneous waste treatment and alternative energy production. An MFC employs exoelectrogenic bacteria to directly convert biodegradable substrates to electricity. The electricity production from MFCs can be maximized at a certain operating condition, which is defined as the maximum power point (MPP). However, it is difficult to maintain an MFC at its MPP during operation, because the power output from MFCs fluctuates constantly due to the changes of microbial activities or environmental conditions. This study developed a maximum power point tracking (MPPT) technique using digitally controlled potentiometers for hysteresis controller based energy harvesting system. Results with lab scale MFC reactors have shown that the system can track the MPP and maintain the maximum energy harvesting in real-time, suggesting that the proposed system can capture the most available energy from MFCs at the most efficient operating point. 


Jae-Do Park, Zhiyong Ren 
High Efficiency Energy Harvesting from Microbial Fuel Cells using a Synchronous Boost Converter 
Journal of Power Sources, In press, doi: 10.1016/j.jpowsour. 2012.02.035 
[ Full Text ]

Microbial fuel cells (MFCs) convert chemical energy stored in biodegradable substrates into direct electricity, which can be used to power remote sensors or offset the energy used during wastewater treatment. Power electronics converters have been developed to replace external resistors and harvest and store energy from MFCs, which is a significant improvement in MFC studies because external resistors only demonstrate power generation potential without actually capturing usable energy. However, the efficiency of conventional diode based energy harvester is low due to the high power loss of the diode. This study presents a synchronous boost converter based MFC energy harvester using a P-channel MOSFET, which improved the system efficiency by 73%, from 43.8% to 75.9%. A modified hysteresis controller was developed to provide precise control during energy harvesting and operating and also prevented reverse current flows. 


Jae-Do Park, Zhiyong Ren 
Hysteresis Controller Based Maximum Power Point Tracking Energy Harvesting System for Microbial Fuel Cells
Journal of Power Sources, In press, In press, doi: 10.1016/j.jpowersour.2012.01.053 
[ Full Text ]

Microbial fuel cell (MFC) is a new approach to accomplish simultaneous waste treatment and alternative energy production. An MFC employs exoelectrogenic bacteria to directly convert biodegradable substrates to electricity. The electricity production from MFCs can be maximized at a certain operating condition, which is defined as the maximum power point (MPP). However, it is difficult to maintain an MFC at its MPP during operation, because the power output from MFCs fluctuates constantly due to the changes of microbial activities or environmental conditions. This study developed a maximum power point tracking (MPPT) technique using digitally controlled potentiometers for hysteresis controller based energy harvesting system. Results with lab scale MFC reactors have shown that the system can track the MPP and maintain the maximum energy harvesting in real-time, suggesting that the proposed system can capture the most available energy from MFCs at the most efficient operating point. 


Jae-Do Park
Design and Implementation of a Fundamental Electric Machine Laboratory using Industrial Devices 
Forthcoming on Conference Proceedings of American Society of Engineering Education (ASEE) Annual Conference 2012 
[ Full Text ]

The design and implementation of the instructional electric machine laboratory is described in this paper. The objectives of this project are to upgrade 50-year old laboratory equipment and to provide students with hands-on experience on up-to-date electric machines, drives and instruments, as well as to improve their understanding of the theory learned from lectures. Instead of the systems especially designed for educational purpose, off-the-shelf industrial devices have been selected for the experiments to make them more realistic and thus closer to work situations, as well as more cost effective. Experiments, hardware components, instruments and student feedback about the laboratory course offered are presented.


Bu-Il Kang*, Jae-Do Park
Wind Power Technologies from the Perspective of System Operator 
Forthcoming on IEEE Symposium on Power Electronics and Machines in Wind Applications (PEMWA) 2012 
[ Full Text ]

Various wind turbines have been developed and operated in distribution systems and transmission systems. The usage of wind power is now rapidly growing worldwide and some leading countries in wind power technologies have been developing new strategies and enhanced requirements for power system security and electrical power quality. But most of power systems have not prepared for them yet. Given the fact that the renewable energy sources, such as wind power, photovoltaic, fuel cells will be getting more importance for the future energy systems with the benefit of emission trading, most of developing countries and power systems that are not preparing for such movement should make their future plan not only for the power system security, but also for their economic development. In this paper, wind power technologies, which is one of the most promising alternative energy sources, is summarized from the viewpoint of power system operation and control.


Jae-Do Park, Zhiyong Ren
Efficient Energy Harvester for Microbial Fuel Cell using DC/DC Converters 
Conference proceedings of IEEE ECCE 2011, September 2011 
Full Text ]

Microbial fuel cell (MFC) is an emerging technology for sustainable energy production. An MFC employs indigenous microorganisms such as biocatalysts and can theoretically convert any biodegradable substrate into electricity, making the technology a viable solution for sustainable waste treatment or autonomous power supply. However, the electric energy currently generated from MFCs is not directly usable due to the low voltage and current output. Moreover, the output power can fluctuate significantly according to the operating points, which makes stable harvest of energy difficult. This paper presents a steady and efficient energy harvester from MFCs using two layers of DC/DC converters. The proposed energy harvester can capture the energy from MFCs at the most efficient operating point and at the same time form the energy into a usable shape.


Jared Candelaria, Jae-Do Park
VSC-HVDC System Protection: A Review of Current Methods 
Conference proceedings of IEEE PSCE 2011, March 2011 
Full Text ]

Currently classical thyristor-based high voltage direct current (HVDC) systems hold the market in bulk power transmission. However, recent advances in semiconductor technology have led to voltage source converter based HVDC (VSC-HVDC) systems becoming a viable competitor. Not only is VSC-HVDC a competitor for transmission but it can also be used in multi-terminal systems, which have become an attractive option for renewable energy applications or for distribution in large cities. As more and more VSC-HVDC systems are installed, the protection of these systems must be taken into account. This paper explores different options and ideas for VSC system protection. 


Jared Candelaria, Jae-Do Park
VSC-HVDC System Protection: A Review of Current Methods 
Conference proceedings of IEEE PSCE 2011, March 2011 
Full Text ]

Currently classical thyristor-based high voltage direct current (HVDC) systems hold the market in bulk power transmission. However, recent advances in semiconductor technology have led to voltage source converter based HVDC (VSC-HVDC) systems becoming a viable competitor. Not only is VSC-HVDC a competitor for transmission but it can also be used in multi-terminal systems, which have become an attractive option for renewable energy applications or for distribution in large cities. As more and more VSC-HVDC systems are installed, the protection of these systems must be taken into account. This paper explores different options and ideas for VSC system protection. 


Jae-Do Park
Simple Flywheel Energy Storage using Squirrel-Cage Induction Machine for DC Bus Microgrid Systems 
Conference proceedings of IEEE IECON 2010, Nov. 2010 
Full Text ]

A simple flywheel energy storage using a squirrel-cage induction machine is proposed in this paper. The suggested motor/generator system operates with an open-loop Volt/Hertz control scheme and utilizes only the nameplate data as machine parameters. Therefore complex controller tuning or machine parameter measurement is not required. Also, any communication between storage units or with other controllers is not necessary because the system uses bus voltage information for charge/discharge operations. The proposed system has an advantage on parallel operation because adding/replacing of units are straightforward. Hence it can easily operate with different types of storage or distributed energy sources in DC bus microgrid systems. Moreover, the proposed control scheme improves the overall stability of the DC bus system. The proposed system has been validated with Matlab simulation and an experimental setup is under construction for verification. 


Jae-Do Park, Claude Kalev, Heath Hofmann 
Modeling and Control of Solid-Rotor Synchronous Reluctance Machine Considering Rotor Flux Dynamics 
IEEE Transactions on Magnetics, Vol.44, No.12, pp.4639-4647, Dec. 2008 
Full Text ]

A model suitable for use in a vector control algorithm for synchronous reluctance machines with solid conducting rotors is presented in this paper. The developed model takes the rotor flux dynamics into consideration and is similar to an induction machine model, yet includes a magnetic saliency of the rotor. Techniques for parameter extraction are discussed. A modification of the model to incorporate the nonlinear magnetic phenomena is also suggested. The influence of nonlinear magnetics on the model-based controller is investigated. The proposed model yields an improved performance for a fast-changing torque command compared to the conventional model when utilized in a current regulator. Experimental results on a 120 kW, 55,000 rpm machine of a flywheel energy storage system validate the performance of the proposed model.


Jae-Do Park, Claude Kalev, Heath Hofmann 
Control of High-Speed Solid-Rotor Synchronous Reluctance Motor/Generator for Flywheel-Based Uninterruptible Power Supplies 
IEEE Transactions on Industrial Electronics, Vol.55, No.8, pp.3038-3046, August 2008 
Full Text ]

A hybrid controller, consisting of a model-based feedforward controller and a PI feedback compensator, for a solid-rotor synchronous reluctance motor/generator in a high-speed, flywheel-based uninterruptible power supply (UPS) application is proposed in this paper. The feedforward controller takes most of the control output of the current regulator based on the machine model, and the PI controllers compensate the possible inaccuracies of the model to improve the performance and robustness of the complete control system. The machine current tracking error caused by parameter inaccuracy in the model-based controller is mathematically analyzed, and utilized to dynamically compensate the estimated flux linkage to eliminate the steady-state error in current regulation. Stability analysis is also presented, and it can be seen that the regulation performance and robustness of the system are improved by the proposed hybrid controller. Simulation and experimental results consisting of a flywheel energy storage system validates the performance of the controller.


Jae-Do Park, Claude Kalev, Heath Hofmann 
Analysis and Reduction of Time Harmonic Rotor Loss in Solid-Rotor Synchronous Reluctance Drive 
IEEE Transactions on Power Electronics, Vol.23, No.2, pp. 985-992, March 2008 
Full Text ]

Synchronous reluctance machines with solid rotor construction have advantages in certain high-speed applications such as flywheel energy storage systems. However, the solid rotor allows the flow of eddy currents, resulting in rotor loss and heat generation. The switching harmonics in the stator voltage supplied by a PWM inverter are one of the sources of the rotor loss. This paper performs an analysis for the time harmonic loss in a solid-rotor synchronous reluctance machine, and investigates design and control issues associated with the inclusion of a three-phase LC filter for reduction of the rotor loss in solid rotor. A two-phase dynamic model of the machine which incorporates the LC filter dynamics is presented. This model is used to predict rotor losses due to switching harmonics generated by the three-phase PWM inverter. A model-based current regulator is utilized, which is modified to include the effects of the LC filter. Experimental results validate the proposed approach.


Jae-Do Park, Gyu-Shik Che, Hai-Won Yang 
A Study on the Water Level Control of Nuclear Power Plant Steam Generator using Adjustable Level Setting at Low Power 
Transactions of KIEE, Vol.41, No.11, 1992, pp. 1305~1315 
[ Full Text ]

The steam generator water level control at low power is very important in the nuclear power plant because the water level is unstable due to shrink and swelling phenomena and sometimes it would cause plant shutdown. For availability and reliability improvement for the water level control of nuclear power plant steam generator which critically impacts the plant availability, steam generator water level control system at low power for the already brought into domestic pressurized water reactors (PWRs) manufactured by Westinghouse is studied, and then, the water level variation depending on the power change at low power is studied variable water level control system in this paper.


Jae-Do Park, Claude Khalizadeh, Heath Hofmann 
Design and control of high-speed solid-rotor synchronous reluctance drive with three-phase LC filter 
Conference Record of the IEEE Industry Applications Conference 2005, 40th IAS Annual Meeting. Vol.1, pp. 715-722, 2-6 Oct. 2005 
Full Text ]

Synchronous reluctance machines with solid rotor construction have advantages in certain high-speed applications such as flywheel energy storage systems. However, the solid rotor allows the flow of eddy currents, resulting in heat generation. A three-phase LC filter can reduce rotor losses due to the switching harmonics generated by a 3-phase inverter. This paper investigates the design and control of a high-speed synchronous reluctance drive with a three-phase LC filter. A two-phase dynamic model of the drive which incorporates the LC filter dynamics is presented. This model is used to predict rotor losses due to switching harmonics using phasor analysis. A feedforward-based current regulator is utilized, which is modified to include the effects of the LC filter. Simulation and experimental results validate the proposed approach.


Jae-Do Park, Heath Hofmann, Claude Khalizadeh 
Feedforward Control of High-Speed Solid-Rotor Synchronous Reluctance Machines With Rotor Dynamics Model 
Conference Record of the IEEE Industry Applications Conference 2004, 39th IAS Annual Meeting. Vol.1, pp. 298~306, 3-7 Oct. 2004 
Full Text ]

An open-loop current regulator for a high-speed synchronous reluctance machine with a solid conducting rotor is presented. A rotor dynamic model is developed which is similar to an induction machine model yet includes a magnetic saliency of the rotor. The model is then used to calculate command voltages for a desired current in an open-loop current regulator. Techniques for parameter extraction and discrete-time models for digital implementation are discussed. Experimental results, including a 120kW discharge of a flywheel energy storage system, validate the performance of the controller.


Jae-Do Park, Gyu-Shik Che, Hai-Won Yang 
Design of a Feed Water Control System (FWCS) using Neural Networks for a Nuclear Power Plant Steam Generator 
Conference Record of the KIEE Fall Annual Conference 1992, KIEE Fall Annual Conference, pp. 400~402, 1992 
[ Full Text ]

© The Regents of the University of Colorado, a body corporate. All rights reserved.

Accredited by the Higher Learning Commission. All trademarks are registered property of the University. Used by permission only.