A High-Reliability Solid-State Ignitron Replacement

The design approach, development, and application of a reliable and efficient silicon power diode ignition replacement assembly are presented. The module design provides for natural convection air cooling and a direct replacement capability in 300-kW ignitron power rectifier units not requiring phase control. The discussions include 1) a brief comparison of the economics favoring its use; 2) design philosophy and criteria, operation of silicon power diodes in parallel without paralleling reactors, protection from damaging high voltage and current transients or overloads, mechanical design and physical requirements for optimum cooling, electrical insulation, and package configuration; 3) dynamic operational test information from prototypes and production samples in the testing laboratory and from field installations; 4) history of a field installation (supervised by the author) with more than 4000 hours of satisfactory operation under rigorous load and environmental conditions.