A METHOD FOR CONTROLLING THE TURNING-OFF PROCESS OF A SOFT SWITCH AND A SOFT SWITCH

摘要

The present invention discloses a method for controlling the turning-off process of a soft switch, when any of the main power switching tubes in the soft switch need to be turned off, comprising: turning on the auxiliary switching tube located in a different position on the bridge arm from the main power switching tube to be turned off, inputting energy to the LC second-order resonant circuit, and determining the energy inputting end moment satisfying the condition that the maximum value of resonant current equals the present load current; when the energy inputting end moment comes, stopping the energy input and turning off the auxiliary switching tube located in a different position on the bridge arm from the main power switching tube to be turned off, and turning on the auxiliary switching tube located in the same position on the bridge arm as the main power switching tube to be turned off; determining the moment when the resonant current is zero, and after 1/4 resonance cycle from this moment, simultaneously turning off the auxiliary switching tube located in the same position on the bridge arm as the main power switching tube to be turned off and the main power switching tube to be turned off. The present invention also discloses a soft switch. Use of the technical solution of the present invention can reduce the extra loss during the turning-off process of the soft switch.