Uso de acoplamento magnético na melhoria de características de algumas estruturas ZVT

• Autor(a) principal: Menegáz, Paulo José Mello
• Data de Publicação: 2005
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/4099
• topic: Engenharia Elétrica; Conversores de corrente elétrica; Eletrônica de potência; Semicondutores de potência; Transistores de potência; 621.3

This Dissertation presents two families of non-isolated DC-DC ZVT-PWM converters which employ a magnetic coupling to implement the topological auxiliary voltage source. The first proposed family of converters belongs to the group of ZVT converters with switched auxiliary voltage source. It makes use of a magnetic coupled regenerative snubber applied to the auxiliary switch of the ZVT converter in order to assure a zero voltage transition commutation during its turn-off. The auxiliary switch turn-on occurs at zero current and the main switch presents both the turn-on and the turn-off at zero voltage, as in the conventional ZVT topology. The magnetic coupling is responsible to produce the necessary conditions for the resonant discharge of the snubber capacitor, transferring the energy stored in the capacitance to the converter input and/or output. A more compact topology is achieved by using the leakage inductance of the magnetic coupling as the resonant inductance itself, which reduces the number of magnetic components of the converter. The second proposition belongs to the group of ZVT converters with DC auxiliary voltage source. In this family of converters, a magnetic coupling between the main and the resonant inductors is used in order to guarantee that the auxiliary switch will work at its minimum total loss point. The main and the auxiliary switch commutation remains unchanged if compared to the commutations of the converter without magnetic coupling. Once both the main and the resonant inductors of the converter are built in the same magnetic core, the number of magnetic components is reduced, as well as the number of EMI sources. For both propositions, equations describing the voltage and current behavior of the main elements of the converter are given. Beside this, a design procedure that allows a quick and simple choice of the magnetic coupled cell elements is also presented. At the end of this work, simulation and experimental results obtained by the construction of the proposed converter prototypes are shown. They validate the equations and design procedures developed in the work and demonstrate the improvement achieved by using the proposed enhancement.