Generator Control System Employing Semiconductor Apparatus

This invention relates generally to new and improved transistor control apparatus for controlling the excitation of rotary generators. In the field of transistor control of generators, especially where it is desired to control relatively large field excitation currents, the problem arises of obtaining suitable transistors having a sufficiently large current carrying capacity to properly control the current flowing in the generator exciting field. It has been found that the answer does not lie in paralleling two or more transistors directly, since only by extremely carefully matching of transistors or by utilizing auxiliary electronic components in the circuit can it be insured that parallel transistors will share the load. In this invention the generator is wound with a plurality of field exciting windings and the output electrodes of a plurality of transistors, respectively, are placed in series with each of the field windings. The input electrodes of the transistors may be connected in parallel, in which case a single control signal is effective to control substantially equally the conductivity of the plurality of transistors