Mechatronics Systems Engineering - Theses, Dissertations, and other Required Graduate Degree Essays

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Modeling and characterization of micro-porous layers in fuel cells

Date created: 
2015-12-02
Abstract: 

Modern hydrogen powered polymer electrolyte fuel cells (PEFCs) utilize a micro-porous layer (MPL) consisting of carbon nanoparticles and polytetrafluoroethylene (PTFE) to enhance the transport phenomena of reactants and products adjacent to the active catalyst layers. The use of MPLs in advanced PEFCs has aided manufacturing of higher performing fuel cells with substantially reduced cost. However, the underlying mechanisms are not yet completely understood due to a lack of information about the detailed MPL structure and properties. In the present work, the 3D phase segregated nanostructure of an MPL is revealed for the first time through the development of a customized, non-destructive procedure for monochromatic nano-scale X-ray computed tomography (NXCT) visualization. Utilizing this technique, it is discovered that PTFE is situated in conglomerated regions distributed randomly within connected domains of carbon particles; hence, it is concluded that PTFE acts as a binder for the carbon particles and provides structural support for the MPL. Exposed PTFE surfaces are also observed that will aid the desired hydrophobicity of the material. Additionally, the present approach uniquely enables phase segregated calculation of effective transport properties, as reported herein, which is particularly important for accurate estimation of electrical and thermal conductivity. Additionally, two analytical models are developed for estimation of thermal conductivity and diffusivity of MPL, as a function of structural properties, i.e., porosity and pore size. Based on these models, the pore size distribution and porosity of an MPL with a high diffusivity and thermal conductivity is proposed. Finally, a performance model is developed that is used to study the effects of MPL properties on fuel cell performance. Overall, the new imaging technique and associated findings may contribute to further performance improvements and cost reduction in support of fuel cell commercialization for clean energy applications.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Erik Kjeang
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

Energy-smart calculation of thermal loads in mobile and stationary heating, ventilation, air conditioning, and refrigeration systems

Date created: 
2015-11-10
Abstract: 

The energy consumption by heating, ventilation, air conditioning, and refrigeration systems forms a large portion of the total energy usage in buildings. Vehicle fuel consumption and emissions are also significantly affected by air conditioning. Air conditioning is also a critical system for hybrid electric vehicles and electric vehicles as the second most energy consuming system after the electric motor. Proper design and efficient operation of air conditioning systems require accurate calculation of thermal loads as well as appropriate design and selection of the refrigeration cycle. The control logic applied to the system further defines the operational costs associated with the performance of the air conditioning or refrigeration system.The common practice in air conditioning engineering includes a primary calculation of thermal loads. Consecutively, the refrigeration system is selected to provide the required cooling or heating load. An alternate design approach in which the thermal loads are not only calculated as the initial design step but are also calculated in real-time is proposed in this thesis. Modern air conditioning systems are equipped with feedback controllers to allow the system to sustain thermal comfort. The real-time calculation and prediction of the room thermal loads improved by measurements is beneficial for energy-efficient control of air conditioning systems especially in vehicle applications that experience highly dynamic load variations. The calculation procedure can be implemented in a load-based controller to provide advanced intelligence for the system operation. This approach can optimize the system performance for the current as well as future conditions and can also be used as a tool for retrofitting existing systems.The objective of the present research is to establish intelligent real-time thermal load calculation methods that can be used to develop energy-efficient control systems in both stationary and mobile air conditioning and refrigeration applications. The proposed methodology consists of developing a variety of models for law-driven and data-driven calculation of thermal loads in mobile and stationary applications. The proposed models are applicable to heating, air conditioning, and refrigeration applications. The contributions of this study include design recommendations that can result in up to 50% increase in energy efficiency for mobile and stationary air conditioning systems.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Majid Bahrami
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

Knowledge discovery for design optimization using correspondence analysis

Author: 
Date created: 
2015-09-28
Abstract: 

In recent years, researchers have made great efforts in tackling the High-dimensional, Expensive (computationally), Black box (HEB) design problems. The high dimensionality and lack of knowledge of the problem usually demand a large number of samples for optimization, which is often impractical due to the total time required to compute the required number of expensive simulations. In this thesis, Correspondence Analysis (CA) is introduced to discover as much information as possible about the black box to minimize the number of samples. The discovered information such as the promising subdomains, important variables, and symmetric variables is used to assist the resampling in an existing optimization algorithm. While being independent from the optimization algorithm, the approached method is applied to the Trust Region based Mode Pursuing Sampling (TRMPS2), a global optimization method developed for HEB problems. The CA based TRMPS2 method (CA_TRMPS) is shown to yield better optima with higher efficiency than TRMPS2. Tests on mathematical benchmark functions and application to a real-world engineering problem show the promise of the proposed approach.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Gary Wang
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Smart Grid Adaptive Volt-VAR Optimization in Distribution Networks

Author: 
Date created: 
2015-12-01
Abstract: 

The electrical distribution networks across the world are witnessing a steady infusion of smart grid technologies into every aspect of their infrastructure and operations. Technologies such as Energy Management Systems (EMS), Distribution Management Systems (DMS) and Advanced Metering Infrastructure (AMI) have partially addressed the needs of the distribution networks for automation, control, monitoring and optimization. Many utilities intend to explore the capabilities of advanced AMI systems for other functionalities within their grids. AMI systems produce an extensive amount of data that can be collected from termination points, for various optimization, control and energy conservation functions. Moreover, deployment of smart grid assets and smart system utilizations provide unprecedented opportunities for network operators and planners to adopt more efficient and reliable strategies for the technical/economic issues of their grids. Accordingly, new smart grid adaptive optimization and control techniques can be constituent components of future distribution grids. The present thesis aims to propose a novel smart grid adaptive solution for one of the well-known techniques typically employed for distribution network voltage and reactive power optimization called Volt-VAR Optimization (VVO). Proposed VVO engine enables capturing AMI data to solve the VVO problem through its comprehensive objective function in quasi real-time intervals. Furthermore, this thesis investigates the impacts of disparate smart grid components such as Distributed Generation (DGs), Electric Vehicles (EVs) and Distributed Energy Resources (DERs) on proposed smart grid adaptive VVO. Solving maintenance scheduling problem of Volt-VAR Control Components (VVCCs), proposing a new solution for VVCC number of switching per day issue, offering a quasi-real-time load modeling approach to enhance the accuracy of energy conservation calculations, presenting a predictive VVO solution and considering Conservation Voltage Reduction (CVR) as a part of VVO objective to save the energy consumption of loads are some of the novel VVO studies presented in this thesis. This thesis examines proposed VVO performance and applicability through a real-time co-simulation platform using advanced communication protocols/standards such as DNP3 and IEC 61850. The results of thesis studies prove that applying proposed VVO engine could considerably enhance smart distribution system levels of accuracy, efficiency and reliability.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Siamak Arzanpour
Gary Wang, Jiacheng Wang
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

Transient internal forced convection under dynamic thermal loads: in clean-tech and automotive applications

Date created: 
2015-07-29
Abstract: 

This research aims to address the thermal behavior of emerging engineering applications with dynamic thermal characteristics. Such applications include: i) clean-tech systems, e.g., powertrain and propulsion systems of Hybrid/Electric/Fuel Cell Vehicles (HE/E/FCV); ii) sustainable/renewable power generation systems (wind, solar, tidal); and iii) information technology (IT) systems (e.g., data centers, e-houses, and telecommunication facilities). In this research, transient internal forced-convection was used to model the thermal characteristics of the cooling systems in the above-mentioned applications. In addition, sinusoidal heat flux was considered, since arbitrary loads can be modeled by a superposition of sinusoidal waves using a Fourier transformation series. Additionally, benchmark driving cycles were used to investigate the thermal characteristics of a cooling system in the context of the real-world application of HE/E/FCV. Firstly, the energy equation was solved analytically for a steady tube flow under an arbitrary time-dependent thermal load. Then sinusoidal heat flux was taken into account, and closed-form relationships were obtained to predict the temperature distribution inside the fluid and the Nusselt number. Finally, the presented results were validated using a commercially available software program: ANSYS Fluent. In the next step, the energy equation was solved analytically for tube flow with an arbitrary flow rate and a given time-dependent heat flux. Sinusoidal heat flux and flow rate were then taken into account; closed-form series solutions for the temperature distribution and Nusselt number of the tube flow were presented. An independent numerical simulation was also performed to validate the models.Additionally, new testbeds were designed and built and a comprehensive experimental study was performed to analyze the thermal behavior of a tube flow under arbitrary time-dependent heat flux. It was shown that there was an excellent agreement between the experimental data and the predictions of the developed models.As a result of the above work, a new model was developed that predicts the minimum instantaneous flow rate to maintain the temperature at a given level under an arbitrary time-dependent heat flux. Compared to conventional steady-state designs, the developed model can result in up to a 50% energy savings while maintaining the temperature of the system below the targeted value.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Majid Bahrami
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

Electro-thermal Modeling of Lithium-ion Batteries

Date created: 
2015-07-16
Abstract: 

The development and implementation of Lithium-ion (Li-ion) batteries, particularly in applications, requires substantial diagnostic and practical modeling efforts to fully understand the thermal characteristics in the batteries across various operating conditions. Thermal modeling prompts the understanding of the battery thermal behavior beyond what is possible from experiments and it provides a basis for exploring thermal management strategies for batteries in hybrid electric vehicles (HEVs) and electric vehicles (EVs). These models should be sufficiently robust and computationally effective to be favorable for real time applications. The objective of this research is to develop a complete range of modeling approaches, from full numerical to analytical models, as a fast simulation tool for predicting the temperature distribution inside the pouch-type batteries. In the first part of the study, a series of analytical models is proposed to describe distributions of potential and current density in the electrodes along with the temperature field in Li-ion batteries during standard galvanostatic processes. First, a three-dimensional analytical solution is developed for temperature profile inside the Li-ion batteries. The solution is used to describe the special and temporal temperature evolution inside a pouch-type Li-ion cell subjected to the convective cooling at its surfaces. The results are successfully verified with the result of an independent numerical simulation. The solution is also adapted to study the thermal behavior of the prismatic and cylindrical-type nickel metal hydride battery (NiMH) batteries during fast charging processes, which demonstrated the versatility of the model. Afterward, to resolve the interplay of electrical and thermal processes on the heat generation and thermal processes, a closed-form model is developed for the electrical field inside the battery electrodes. The solution is coupled to the transient thermal model through the heat source term (Joulean heat). The results of the proposed multi-physic are validated through comparison with the experimental and numerical studies for standard constant current discharge tests. The model results show that the maximum temperature in the battery arises at the vicinity of the tabs, where the ohmic heat is established as a result of the convergence/divergence of the current streamlines. In the second part of the study, an equivalent circuit model (ECM) is developed to simulate the current-voltage characteristics of the battery during transiently changing load profiles. The ECM that is calibrated by a set of characterization tests collected over a wide range of temperature, then coupled with a numerical electro-thermal model. The validated ECM-based model is capable of predicting the time variation of the surface temperature, voltage, and state of charge (SOC) of the battery during different driving cycles and environmentaltemperatures.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Majid Bahrami
Department: 
Applied Sciences:
Thesis type: 
(Thesis) Ph.D.

Nonlinear Control and Application of Power Electronics Boost Converters

Date created: 
2014-07-21
Abstract: 

In this thesis, we investigate the development of novel control schemes for single and three phase boost converters operated in different modes of conduction. Study is conducted on development of controllers based on the nonlinear dynamic characteristics of the converters and characteristics such as nonminimum phase behavior in boost converters that give rise to control challenges. The control strategies are further applied to certain areas in sustainable energy systems including maximum power point tracking of photovoltaic panels, load current control of power converters, and energy regenerative suspension in vehicular systems. To this end, the analytical behavior of a boost converter is studied and utilized to design nonlinear controllers to control the input resistive behavior of the converter. The performance of proposed controllers are verified through simulations and experiments on single stage converters. Finally, the design of a feedback control system for input resistance control of a three-phase bidirectional converter is studied. A sliding mode controller is utilized in an application involving energy regeneration for a mechanical suspension system. A permanent magnet machine and a linear vibration generator are utilized along with the proposed control strategy to achieve regenerative damping in a proof-of-concept suspension system. The simulation and experimental results verify that the proposed controller can successfully provide desired damping for mechanical vibrations while storing the vibration energy in battery.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences:
Thesis type: 
(Thesis) Ph.D.

Optimization of a Low-melting Alloy for Fused Filament Fabrication

Date created: 
2015-08-13
Abstract: 

With low-cost Fused Filament Fabrication (FFF) systems proliferating among researchers, developing new filament materials to expand the design capabilities of 3D printed objects has become a focus for research. One material property that has been difficult to achieve though is high conductivity, which would enable the integration of embedded circuitry into functional 3D printed devices. This thesis presents the optimization and integration of low-melting alloys into a FFF system for the production of FFF metal components. The material, extrusion system, and the print parameters were optimized to enable reliable extrusion of the selected non-eutectic alloy. By combining this new material with existing FFF plastics, a 3D printed device with functional electronic circuits will become possible.

Document type: 
Thesis
File(s): 
Video of Sample 1 being printed
Supervisor(s): 
Woo Soo Kim
Department: 
Applied Sciences:
Thesis type: 
(Thesis) M.A.Sc.

Design and development of A novel slurry pump using Transmission Roller

Author: 
Date created: 
2015-08-12
Abstract: 

The oil and gas industry needs a simple and compact pump that could deal with slurry and other highly viscous or erosive fluid. The pump should also be able to fit in limited space of a borehole while maintaining comparable or higher efficiency than the current applications. Inspired by the algebraic screw, a new design of power transmission device, named as Transmission Roller, is introduced in this work and incorporated into a diaphragm pump. This mechanism converts rotary motion into linear motion and shows promises of high efficiency with its compact structure. Similar mechanisms have never been used in a hydraulic application before. A pump prototype utilizing the Transmission Roller is built and tested with water to prove its functionality. The transmission efficiency of the transmission roller prototype is 73.6%. The Transmission Roller efficiency for the final production pump design is expected to be 96.3%, higher than other designs of the same kind.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Siamak Arzanpour
Gary Wang
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Feature extraction and classification of skiing/snowboarding jumps with an integrated head-mounted sensor

Date created: 
2015-08-24
Abstract: 

With advancing technology in miniature MEMS sensors, wearable devices are becoming increasingly popular, facilitating convenient activity detection. One particular application is in sports performance monitoring. This thesis presents novel real-time jump detection and classification algorithms in skiing and snowboarding using a head-mounted MEMS-based inertial measurement unit (MEMS-IMU), which is integrated with a barometric pressure sensor. The key performance variables of the jump are extracted and evaluated for training and/or entertainment purposes. In contrast to the existing jump detection algorithms based on acceleration signals, the proposed algorithm uses vertical velocity and air time in addition to acceleration in the vertical direction. A support vector machine (SVM) is applied to generate a classification model. The jumps are classified into four different groups – Ollie, Standard, Drops, and Step up jumps. The experimental results show that by incorporating the velocity and air time into the detection algorithm, the sensitivity and specificity increase dramatically to 92% and 93%, respectively. In addition, the proposed classification model achieved 80.5% accuracy.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Edward J. Park
Greg Mori
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.