An optimum gate drive for high power GTO thyristors

The description and design of an optimum gate/base drive for current-controlled-type self-commutated semiconductor switches such as gate turn-off thyristor (GTO) or bipolar transistors are presented. The major disadvantages of the conventional gate/base drive circuits are that they impose timing limitations (such as minimum off-time and maximum on-time), have poor efficiency, and use a reduced DC supply which adversely affects the current rise/fall times. To overcome these problems, a special MOSFET-based current shaping circuit is introduced which minimizes the rise time, significantly reduces the switching losses, is nearly lossless, and does not suffer from any timing limitations. Experimental results verify the performance of the proposed gate/base drive