Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- A Comparative analysis of a three-phase DAB and an improved LLC bidirectional DC/DC converter for wide input and output voltage range applications(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-11-04) Escobar Pescina, Luis Arturo; Escobar Valderrama, Gerardo; mtyahinojosa, emipsanchez; Galluzzi Aguilera, Renato; Pool Mazun, Erick I.; Aqui Tapia, Juan; Escuela de Ingeniería y Ciencias; Campus Monterrey; Valdez Reséndiz, Jesús EliasBidirectional DC/DC power conversion is a key element in vehicle electrification to provide auxiliary power, typically for battery charging and discharging. There are currently various challenges in single stage isolated bidirectional DC/DC conversion that limit efficiency, especially for wide input and output voltage range conditions. The Dual Active Bridge (DAB) is a popular topology for this purpose; however, it presents a hard-switched operation under wide voltage and partial load conditions, due to its limited soft-switching region using typical Single-Phase Shift (SPS) modulation. Resonant converters, on the other hand, possess attractive features such as wide ZVS region, high frequency operation with low switching power losses, high efficiency at a wide voltage range and high power density that can potentially solve the current limitations. The LLC resonant tank is one of the most commonly used configurations, even though it does not have a symmetric voltage gain curve in forward and backward energy flow modes, it can reduce the component count and increase power density compared to a more complex tank network such as the CLLC. However, the conventional LLC topology has limited backward voltage gain that leads to a condition referred to in this thesis as the inequality problem, and for wide input voltage range it is necessary to add a mechanism that is capable of dynamically changing the converter gain to further step up the input voltage and meet the system requirements. Hence, this thesis presents the following: 1. An improved LLC resonant converter with a center-tapped transformer that can dynamically change the transformer turns-ratio in a tap-changer fashion and considerably increase the input and output voltage range. 2. A comparative analysis between the popular Three-Phase DAB converter and the proposed Center-Tapped LLC (CT-LLC) for a 15-kW application through their simulation models in OrCAD using non-ideal PSpice components. 3. Relevant conclusions derived from the comparative study that highlight the benefits and drawbacks of each topology according to efficiency, performance, reliability, and cost metrics.
- Development of a DC-DC converter-based balancing system for Lithium-ion battery cells based on State of Power reference(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-06) Martínez Barrón, Abraham Alberto; Escobar Valderrama, Gerardo; puemcuervo; Valdez, Jesús; Escuela de Ingeniería y Ciencias; Campus Monterrey; Schacht, RicardoIn recent years, Li-ion battery packs have become a major component of new technologies like energy storage systems and electric vehicles. Due to the safety limitations inherent to Li-ion battery cells, these packs need to be operated under precise voltage, temperature, and current conditions, which are variables supervised by a BMS. Depending on the application, battery packs are often comprised of several individual cells. However, each battery cell has slight variations, which can lead to performance and service life issues. This problem is addressed by implementing different types of balancing systems. Nevertheless, current methodologies face several limitations, such as a low energy efficiency for passive systems and high costs and complexity for active circuits. A new balancing system, consisting of the combination of a modular active DC-DC converter-based topology, a multi-factor balancing algorithm, and a control strategy for balancing current based on SoP, is developed in this research project. The resulting system can expand the runtime of the battery pack, as the energy is distributed better among cells. Besides, the energy that can be injected into the battery pack during charging has also been increased, as the excess of energy is moved from overcharged cells to the rest before anyone of them reaches its top voltage.