No abstract

3GPP has been working on a new network infrastructure based on unlicensed spectrum known as LTE Secondary Cell (SCell) in a carrier aggregation scenario in which LTE user terminals would still be anchored to an LTE Primary Cell (PCell) over licensed spectrum. On this scenario, best-effort content would be delivered on the unlicensed band SCell, while QoS traffic and control signaling would still be a PCell responsability. This work makes a performance analysis of 3GPP's solution, named LTE-LAA, which allows the LTE system to operate on unlicesend spectrum. It is also analysed the impact of this new technology on the performance of Wi-Fi systems in the same band. Resumo-O 3GPP está criando uma nova infraestrutura de rede denominada LTE Secondary Cell (SCell). Baseada em espectro não-licenciado e em um cenário de agregação de portadora, os terminais LTE ainda estariam conectados a uma LTE Primary Cell (PCell) via espectro licenciado, trafegando sinalização e dados com restrições de QoS, mas o conteúdo best-effort seria transportado pela SCell. Este trabalho faz uma análise de desempenho da solução do 3GPP, denominada LTE-LAA (License Assisted Access), a qual permite que o sistema LTE opere em espectro não-licenciado. Analisa-se também o impacto desta nova tecnologia no desempenho de sistemas Wi-Fi operando na mesma banda.

No abstract

Recently, many non-conventional three-phase inverters, topologies for green energy source grid-connection systems, and electric drives have been proposed. Simplifying the inverter circuit is crucial to analyze and solve their models in order to design them. The main goal of the study is centered on obtaining a single-phase equivalent circuit and space state model from non-conventional three-phase inverters based on bidirectional direct current–direct current (DC–DC) Buck-Boost topology using isolated gate bipolar transistors (IGBT). From just one phase of the three-phase inverter, the single-phase equivalent circuit was obtained by means of Kirchhoff’s laws. The equivalent circuit operation steps were presented in order to obtain the space state model. Finally, the equivalent circuit was simulated, and experimental results with a 200 W three-phase inverter feeding a resistive, inductive, and capacitive loads were performed to confirm the theoretical and simulation analyses. The results show the state space dynamic behavior variables of single-phase and three-phase models are quite similar. Therefore, it can be concluded that the proposed circuit can be used with property to represent equivalent single-phase models of non-conventional three-phase inverters.