Circuit protection and filtering

The final session of the 1976 IEEE Power Electronics Specialists Conference included four papers on various techniques for current limiting or surge voltage reduction in power processing circuits. One paper dealt with the problems of EMI and another discussed power factor and filtering problems The first paper by Wadlington described a current-limiting circuit in a dc to dc converter. Current sensing was provided on the primary side of the transformer. This approach provides protection for the switching transistors from both overload and transient overcurrent conditions and also prevents saturation of the transformer. The circuit was designed to have slow dynamic response near the threshold of current limiting and fast dynamic response for large overload currents.