The main objective of this project is to study the analysis and design of an isolated three-phase bidirectional dc-dc converter connected to the dc microgrid system. The proposed topology achieves efficient power conversion with a wide input voltage range, continuous input current, and bidirectional operation. In forward mode operation, the topology acts as a three-phase push-pull converter to reach a step-up voltage conversion ratio (90 to 450 V). In backward mode operation, the converter acts as an interleaved flyback converter to provide a step-down voltage conversion ratio (450 to 90 V). Over and above that, in both operation senses, the dc voltage gain is presented. The main advantages of this topology are high-switching frequency, the three-phase transformer that provides galvanic isolation between the dc voltage link bus to the battery or ultra-capacitor storage, and input/output filters size reduction.Besides, a fewer number of power switches, the frequency of output voltage, and input current ripple are three times higher than the switching frequency.The three active switches are connected to the same reference, which simplifies the gate drive circuit. Ultimately, the theoretical analysis of the proposed topology is carefully confirmed with the experimental results of the 4 kW converter prototype. K E Y W O R D Sbidirectional dc-dc converter, coupled inductor, interleaved flyback, microgrid, push-pull converter, three-phase transformer

No abstract

No abstract

No abstract

Calcium phosphate bioceramics obtained from raw materials are potential bone substitutes in orthopedic and dental applications. Calcium phosphates attained from calcareous shells using wet methods provide an interconnected microporous framework, shown to be promising and contribute to cell adhesion and proliferation. This study aimed to characterize three different calcium phosphate ratio compositions: (i)1.4, (ii)1.6 and (iii)1.7 molar, sintered for 2 hours at 1100°C and 1200°C. Scanning electron microscopy field effect [FEG] and confocal were used to assess microstructural characterization and Arthur method to determine open porosity. FEG and confocal analyses showed good grain coalescence, sinterability and well defined interfaces for all Ca/P molar at 1100°C and 1200°C. Open porosity and hydrostatic density exhibit better results when using Ca/P molar ratio (iii)1.7 at 1100°C. The results showed that open porosity is related to Ca/P ratio and by temperature. As the Ca/P increases so does the open porosity. Inversely occurs for temperature. As the temperature increases the porosity decreases and in parallel, the grain size increases.