ABSTRACT
In order to decrease the switching loss, power semiconductor devices have to switch at zero current or zero voltage. Resonant circuits equipped with passive components have been introduced near the power switch to achieve either zero current transition (ZCT) or zero voltage transition (ZVT). Equations and limits of operation have been produced. The operation of a H-bridge converter with galvanic isolation through a transformer has been defined with fixed 50% duty cycle and phase-shift control in between the left-side leg and the right-side leg. The converter operational states have been explained separately and it has been shown that, in certain conditions, switching at zero voltage can be achieved. There are specialized integrated circuits for transistor control on the primary side, as well as on the secondary side. This is the Phase Shift Power Converter. An alternative to the Phase Shift Power Converter is offered with the LLC Converter. A series resonant circuit is built on the primary side of the transformer, and operation with ZVT or ZCT can be achieved depending on the operating switching frequency. Numerical examples and simulation results follow the presentation.
