Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
Browse
3 results
Search Results
Item Modeling and control of hybrid wind/photovoltaic/fuel cell distributed generation systems(Montana State University - Bozeman, College of Engineering, 2006) Wang, Caisheng; Chairperson, Graduate Committee: M. Hashem NehrirDue to ever increasing energy consumption, rising public awareness of environmental protection, and steady progress in power deregulation, alternative (i.e., renewable and fuel cell based) distributed generation (DG) systems have attracted increased interest. Wind and photovoltaic (PV) power generation are two of the most promising renewable energy technologies. Fuel cell (FC) systems also show great potential in DG applications of the future due to their fast technology development and many merits they have, such as high efficiency, zero or low emission (of pollutant gases) and flexible modular structure. The modeling and control of a hybrid wind/PV/FC DG system is addressed in this dissertation. Different energy sources in the system are integrated through an AC bus. Dynamic models for the main system components, namely, wind energy conversion system (WECS), PV energy conversion system (PVECS), fuel cell, electrolyzer, power electronic interfacing circuits, battery, hydrogen storage tank, gas compressor and gas pressure regulator, are developed. Two types of fuel cells have been modeled in this dissertation: proton exchange membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC).Item A new DC-DC converter for fuel cell powered residential power generation systems(Montana State University - Bozeman, College of Engineering, 2006) Sharma, Rahul Rajiv; Chairperson, Graduate Committee: Hongwei GaoThis thesis presents a new topology for an isolated DC-DC converter for low voltage to high voltage conversions at high power. The proposed converter is targeted for use in fuel cell powered residential power generation systems, where low voltage to high voltage conversion at high power (>5KW) and isolation between input and output are required. Conventional DC-DC converters like forward, half bridge and full bridge for such applications need to have high turn ratio in their power transformers, to enable the high voltage boosting. This high turns ratio of the transformers results in high leakage inductance which reduces the converter's efficiency and increases the difficulty in control. The proposed converter overcomes this problem by utilizing the leakage inductance for energy conversion instead of considering it as a parasite. This reduces the problems of low efficiency and difficulty of control, caused by the leakage inductance.Item A new islanding detection technique for distributed generation(Montana State University - Bozeman, College of Engineering, 2006) Menon, Vivek Viswanathan; Chairperson, Graduate Committee: M. Hashem NehrirThe phenomenon of unintentional islanding, which occurs when a distributed generator (DG) continues to feed power into the grid when power flow from the central utility source has been interrupted, can result in serious injury to the linemen who are trying to fix the line. Several strategies have been proposed in the past to avoid such an occurrence. Of the existing islanding detection propositions two schemes one of which is an active technique (the positive feedback technique) and the other one a passive technique (the VU and THD technique) are found by the author to be very effective but not without drawbacks. The principles of these strategies are combined to obtain a new hybrid islanding detection technique for synchronously rotating DGs. Simulation results show that the proposed hybrid technique is more effective than each of the above schemes. Simulation results are given for two testbeds to verify the advantages of the proposed hybrid islanding detection technique.