Class of 2013 Abstract / Specific Aims: To compare the Comprehensive Medication Review (CMR) rate for Workflow Model #1 (used in 2010) to the CMR rate for Workflow Model #2 (used in 2011) at the Medication Management Center (MMC). Methods: A retrospective database analysis was completed in which Comprehensive Medication Review (CMR) completion rates for 2010 and 2011 were assessed. Comparison included only Center for Medicare and Medicaid Services (CMS) contracts that the Medication Management Center (MMC) provided Medication Therapy Management (MTM) services for both in 2010 and 2011. Data was used to determine the effect a process change had on CMR participation rate at the MMC and best practices for improving the rate of Medication Therapy Management Program (MTMP) beneficiaries participating in a CMR. Main Results: In 2010, patient participation and response to a CMR offer letter was low (0.2%). The changes in process yielded an increase in the CMR completion rate (6.93%); this in turn yielded higher performance measurements for prescription drug plans. Conclusion: Workflow modifications, including a pro-active secondary CMR offer, led to a marked increase in member participation and CMR rates. Patients are more apt to consent to a CMR if they are called for a specific medication related problem. It is recommended to continue to convert TMR calls to CMRs whenever possible, monitor CMR rates at least quarterly, and make cold calls where needed to increase CMR percentages.

This thesis investigates issues affecting grid synchronisation of VSC-HVDC systems with particular regard to, but not limited to, offshore wind power generation during the complex but potentially serious behaviours following solar storms. An averaged value model (AVM) for the contemporary modular multilevel converter (MMC) based VSC-HVDC system is developed and is used in combination with different phase-locked loop (PLL) models and the unified magnetic equivalent circuit (UMEC) transformer model to assess the impacts of geomagnetically induced current (GIC) on grid synchronisation of an offshore VSC-HVDC system. GIC is DC current flowing in the earth caused by strong geomagnetic disturbance events. GIC enters the electric utility grid via the grounded transformer neutral and can cause severe saturation to transformers. This in turn causes disruptions to grid synchronisation. The main contribution of this thesis is that effects of GIC are studied using the UMEC transformer model, which can model saturation. The assessment leads to the development of enhanced fundamental positive sequence control (EFPSC) which is capable of reducing the stress on the system during GIC events. The methods developed can also be applied to other non-symmetrical AC events occurring in VSC-HVDC such as single-phase faults. Additional contributions of the thesis are:A mathematical model of the MMC is derived and forms the foundation of the AVM. The AVM is verified against a detailed equivalent-circuit-based model and shows good accuracy. The PLL is the essential component for grid synchronisation of VSC-HVDC system. Different PLLs are studied in detail. Their performance is compared both qualitatively and quantitatively. This appears to have been done for the first time systematically in the public literature. The UMEC model is verified using hand calculation. Its saturation characteristic is matched to a predefined B-H curve and is also verified. The verifications show that this model is capable of modelling transformer saturation and thus is suitable for this study. The consolidation of the AVM, PLL, UMEC, GIC and EFPSC provides an insight into the how the MMC based VSC-HVDC system behaves under severe geomagnetic disturbances and the possible methods to mitigate the risks and impacts to the power grid.

The UK Government has identified that nearly 15% of the UK’s electricity generation must come from offshore wind by 2020. The reliability of the offshore windfarms and their electrical transmission systems is critical for their feasibility. Offshore windfarms located more than 50-100km from shore, including most Round 3 offshore windfarms, are likely to employ Voltage Source Converter (VSC) High Voltage Direct Current (HVDC) transmission schemes. This thesis studies factors which affect the reliability of VSC-HVDC transmission schemes, in respect to availability, protection, and system modelling. The expected availability of VSC-HVDC systems is a key factor in determining if Round 3 offshore windfarms are technically and economically viable. Due to the lack of publications in this area, this thesis analyses the energy availability of a radial and a Multi-Terminal (MT) VSC-HVDC system, using component reliability indices derived from academic and industrial documentation, and examining the influence of each component on the system’s energy availability. An economic assessment of different VSC-HVDC schemes is undertaken, highlighting the overall potential cost savings of HVDC grids. The connection of offshore windfarms to a MT HVDC system offers other potential benefits, in comparison to an equivalent radial system, including a reduction in the volume of assets and enhanced operational flexibility. However, without suitable HVDC circuit breakers, a large MT HVDC system would be unviable. In this thesis, a review of potential HVDC circuit breaker topologies and HVDC protection strategies is conducted. A HVDC circuit breaker topology, which addresses some of the limitations of the existing designs, was developed in this thesis, for which a UK patent application was filed. Accurate simulation models are required to give a high degree of confidence in the expected system behaviour. Modular Multi-level Converters (MMCs) are the preferred HVDC converter topology, however modelling MMCs in Electromagnetic Transient (EMT) simulation programs has presented a number of challenges. This has resulted in the development of new modelling techniques, for which the published validating literature is limited. In this thesis these techniques are compared in terms of accuracy and simulation speed and a set of modelling recommendations are presented. Cable models are the other main DC component which, upon analysis, is found to have a significant impact on the overall model’s simulation results and simulation time. A set of modelling recommendations are also presented for the leading cable models. Using the modelling recommendations to select suitable MMC models, radial and MT EMT MMC-HVDC models for the connection of typical Round 3 windfarms are developed in this thesis. These models are used to analyse the steady-state and transient performance of the connections, including their compliance to the GB grid code for AC disturbances and reactive power requirements. Furthermore, the MT model is used to investigate the effect of MT control strategies on the internal MMC quantities.

Nanotechnology as a field has the potential to answer some of the major challenges that mankind faces in regards to environmental sustainability, energy generation and health care. Though, solutions to these concerns can not necessarily rely on our current knowhow. Instead, it is reasonable to expect that humanity must adapt and learn to develop new materials and methods to overcome the adversities that we are facing. This master thesis has involved developing novel materials, serving as a small step in the continuous march towards a bright future where this is possible. More specifically, this work sought to combine mesoporous magnesium carbonate with various metal-organic frameworks to utilize the beneficial aspects from each of these constituents. The ambition was that these could be joined to render combined micro-/mesoporous core-shell structures, with high surface areas and many active sites whilst maintaining a good permeability. Numerous different synthesis routes were developed and explored in the pursuit of viable routes to design novel materials with potential future applications within for instance drug delivery, water harvesting from air and gas adsorption. Coreshell structures of the hydrophilic mesoporous magnesium carbonate covered with the hydrophobic zeolitic imidazole framework ZIF-8 was successfully synthesized for the first time, and practical studies demonstrated a dramatically enhanced water stability, which is perceived to have an impact on further research on these materials. ZIF-67 was also combined with mesoporous magnesium carbonate in a similar manner. Further, Mg-MOF-74 was grown directly from mesoporous magnesium carbonate, where the latter acted as a partially self-sacrificing template, with the aim of rendering a porous hierarchical structure with contributions from the micro- and mesoporous ranges. The outcomes of all these syntheses were characterized using several analyzing methods such as scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and nitrogen sorption analysis.

This thesis examines alternatives for power supply for a heavy truck application based on five different modular multilevel converter configurations that ultimately feed a 3-phase motor. Advantages and disadvantages of the different configurations are being discussed as well as other important factors that play a role in what configuration that is beneficial for the intended application. How half- or full-bridge submodules and battery cells relate to each other to achieve a desired voltage are being explained and calculated. Power losses of the converter submodules are being calculated as well as how a specific battery capacity, with increasing average power consumption, performs uphill according to set requirements. It turns out to be the double-armed modular multilevel converter configurations that has the best performance when it comes to utility, energy storage and the lowest power losses.

Batteries are becoming popular in the trend of electrification. Performance andlifespan of a battery pack are closely related to how it has been utilized. Withproper balancing control to slow down aging process, variances of capacity andresistance between battery cells can be maintained at a better level. Among balancing methods, dissipative balancing is still the most common method for itssimplicity in control, low cost and high speed. Non-dissipative balancing methods like converter-based and capacitor-based are of researchers’ interest becauseof less heat generated and superior efficiency. In this thesis, the converter-based balancing method is investigated. A modular multilevel converter (MMC) with Pulse-Width Modulation (PWM) pattern iscompared with another MMC with Nearest-Level Modulation (NLM). The speedto balance six battery sub-modules, output power and battery current harmonicsare examined.

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Due to the increased consumption of energy in the modern era, many new installations of different energy solutions are required. One of the more preferred is the renewable category, which governs vast technologies ranging from wind, solar, hydro, and nuclear power. One major issue is that they are usually located up to thousands of kilometers away from the load source. Thus, a reliable transmission system is a must. For such applications, a high-voltage direct current power transmission system (HVDC) is the favorable option, most of the modern types use a modular multilevel voltage source converter (MMC) to execute the AC/DC conversion and vice versa. The control of such devices is ultimately dependent on the modulation method, it serves as a key component of the stability of the whole system. Four different variants of description for such a control method are found in the published literature, as more methods can be found, but the focus is on the four introduced. Therefore, the aim of this master's thesis is to investigate how the highlighted standard modulation methods affect the total system's behavior. Note that the implementation by the company, referred to in this context as the benchmark method, is being compared to assess its efficacy against established standard modulation methods. Detailed comparison involving this method is intentionally omitted. First, the underlying system components are described using circuit topology, which serves as the first course before the analytical derivation using dynamic modeling. By obtaining the final dynamic expression and equation for the insertion index, a detailed control strategy is displayed. The total control system is separated into two parts, one governed by the higher-level controllers and one governed by the modulation methods. As the former is predefined and given, therefore, it will be referred to as the "black box." Then a comprehensive method regarding the implementation of modulation methods is provided, serving as the most crucial part of the work. Several different studies are conducted, including harmonic analysis, fault studies, impedance scanning, and screening studies of torsional interaction. The result indicated that some degree of differences can be concluded between the modulation methods, several cases showed that controlling done in a closed loop manner is the preferred option due to its accuracy and robustness. Some of the investigated modulation methods showed severe oscillations in circumstances where the connected grids were weak. Due to the complexity of the overall system, including higher-level controllers, no direct conclusion can be drawn to definitively say whether any of the modulation methods have a clear advantage in every tested aspect. But at least, based on the results obtained in this work, in this specific simulation set-up, the closed loop method is indeed the preferred option.

The modular multi-level converter (MMC) is the most prominent interface converter used between the HVDC grid and the HVAC grid. One of the important design challenges in MMC is to reduce the capacitor size. In the current practice, a rather large capacitor bank is required to store line-frequency related circulating energy, even though a number of control strategies have been introduced to reduce the capacitor voltage ripples. In the present paper, a novel control strategy is proposed by means of harmonic injections in conjunction with gain control to completely eliminate both the line frequency and the second-order harmonic of the capacitor voltage ripple. Ideally, the proposed method works with the full bridge topology. However, the concept also works with half bridge topology with a significant reduction of line frequency related ripple. To gain a better understanding of the nature of circulating energy and the means of reducing it, the method of state plane analysis is employed to offer visual support. In addition, the design trade-off between full bridge MMC and half bridge MMC is presented and a novel control strategy for a hybrid MMC is proposed. Finally, the work is supported with a scaled down hardware demonstration. / Master of Science