Protected exciter for an electrical power generator and associated methods
View Patent ↗An exciter for an electrical power generator includes a shaft, an armature connected to the shaft, a field surrounding the armature to cause the armature to generate an alternating current, and a rectifying wheel The rectifying wheel includes a plurality of semiconductor switching devices connected to the rectifying wheel and arranged in a bridge configuration for rectifying the alternating current from the field. A respective non-linear protection device is connected in parallel with each of the semiconductor switching devices.
1. An exciter comprising:
a shaft;
an armature connected to said shaft;
a field surrounding said armature to cause said armature to generate an alternating current; and
a rectifying wheel connected to said shaft and comprising
a plurality of pairs of heat sinks;
a plurality of semiconductor switching devices arranged in a bridge configuration for rectifying the alternating current from said armature and with each semiconductor switching device being mounted between a respective pair of heat sinks, and
a respective non-linear protection device connected in parallel with each semiconductor switching device and comprising a non-linear material layer positioned between the heat sinks and electrically conductive through the heat sinks to the semiconductor switching device to provide protection for commutation voltage spikes.
2. An exciter according to claim 1 wherein each non-linear protection device is positioned adjacent a respective semiconductor switching device and comprises a non-linear material layer.
3. An exciter according to claim 2 wherein said non-linear material layer comprises an elastomeric material.
4. An exciter according to claim 3 wherein said elastomeric material layer comprises a silicone elastomer with silicon carbide therein.
5. An exciter according to claim 1 wherein each non-linear protection device further comprises a pair of electrodes carried in spaced apart relation by the pair of heat sinks.
6. An exciter according to claim 5 wherein each non-linear protection device further comprises an insulated stud mounting the respective pair of electrodes and non-linear material layer.
7. An exciter according to claim 2 wherein said non-linear material layer has an annular shape surrounding the respective semiconductor switching device.
8. An exciter according to claim 1 wherein each semiconductor switching device comprises a pair of spaced apart electrodes and an integrated circuit therebetween; and wherein the respective non-linear protection device comprises a non-linear material layer extending between said electrodes.
9. An exciter according to claim 8 wherein each semiconductor switching device further comprises a housing surrounding said integrated circuit; and wherein said non-linear material layer is within said housing.
10. An exciter according to claim 8 wherein each non-linear protection device further comprises a spring member connected in series with said non-linear material layer.
11. An exciter according to claim 1 wherein each semiconductor switching device comprises a diode.
12. A rectifying wheel for an exciter and comprising:
a plurality of pairs of heat sinks;
a plurality of semiconductor switching devices arranged in a bridge configuration for rectifying alternating current, and with each semiconductor switching device being mounted between a respective pair of substantially parallel conductive plates forming heat sinks and conductive therewith; and
a respective non-linear protection device connected in parallel with each semiconductor switching device and comprising a non-linear material layer positioned between said heat sinks and electrically conductive through said heat sinks to said semiconductor switching device to provide protection for commutation voltage spikes.
13. A rectifying wheel according to claim 12 wherein said non-linear material layer comprises an elastomeric material.
14. A rectifying wheel according to claim 12 wherein each non-linear protection device further comprises a pair of electrodes carried in spaced apart relation by the respective pair of heat sinks.
15. A rectifying wheel according to claim 12 wherein said non-linear material layer has an annular shape surrounding the respective semiconductor switching device.
16. A rectifying wheel for an exciter and comprising:
a plurality of pairs of heat sinks;
a plurality of semiconductor switching devices connected in a bridge configuration for rectifying the alternating current, each semiconductor switching device being mounted between a respective pair of heat sinks and comprising a pair of spaced apart, substantially parallel conductive plates forming electrodes and an integrated circuit positioned between and connected to the electrode; and
a respective non-linear protection device connected in parallel with each semiconductor switching device, each non-linear protection device comprising a non-linear material layer positioned between the heat sinks and electrically conductive through the heat sinks to the semiconductor switching device to provide protection for commutation voltage spikes.
17. A rectifying wheel according to claim 16 wherein said non-linear material layer comprises an elastomeric material.
18. A rectifying wheel according to claim 16 wherein said non-linear material layer has an annular shape surrounding the respective integrated circuit.
19. A rectifying wheel according to claim 16 wherein each semiconductor switching device further comprises a housing surrounding said integrated circuit; and wherein said non-linear material layer is within said housing.
20. A rectifying wheel according to claim 16 wherein each non-linear protection device further comprises a spring member connected in series with said non-linear material layer.
21. A rectifying wheel according to claim 16 wherein each semiconductor switching device comprises a diode.
22. A method of protecting semiconductor switching devices of a rectifying wheel for an exciter, the method comprising:
forming a plurality of pairs of heat sinks;
arranging a plurality of semiconductor switching devices in a bridge circuit configuration;
mounting each semiconductor switching device between a respective pairs of heat sinks; and
connecting in parallel with each semiconductor switching device a respective non-linear protection device that is formed from a non-linear material layer positioned between the heat sinks and electrically conductive through the heat sinks to the semiconductor switching device to provide protection for commutation voltage spikes.
23. A method according to claim 22 wherein connecting comprises connecting a respective non-linear protection device comprising a non-linear material layer.
24. A method according to claim 23 wherein the non-linear material layer comprises an elastomeric material.
25. A method according to claim 23 wherein connecting comprises connecting a respective non-linear protection device comprising a non-linear material layer so that the non-linear material layer has an annular shape surrounding a respective semiconductor switching device.