Full bridge phase displaced resonant transition circuit for obtaining constant resonant transition current from 0 DEG phase angle to 180 DEG phase angle

摘要

In a full-bridge phase displaced resonant transition circuit a center-tap is placed on the power transformer primary winding. The center-tap is connected to an inductor at one end with another end of the inductor connected to a large capacitor. The other end of the capacitor is connected to circuit common. During the time that a diagonal of the switching bridge is conducting, current will increase in the inductance of the power transformer primary winding. When the bridge changes to a horizontal conduction situation, the current in the power transformer primary winding will stop increasing and will essentially hold its value until the next diagonal conduction. Concurrently during the horizontal conduction the current in a resonant inductor will increase. When the bridge changes again to diagonal conduction the resonant inductor will stop increasing and essentially hold its value until the next horizontal conduction. Through this operation, at any given time there is current in one or the other inductances which is increasing and thus storing energy to be used for resonant transition even at zero phase no-load conditions.