Evaluation of Liquid Dielectrics to Improve Spiral Generator Lifetimes

Spiral generators can be used to generate high-voltage pulses on the order of singles to hundreds of nanoseconds with a single switch. Their compact design makes them attractive for high-voltage pulse generation in volume and weight sensitive applications, but it also makes them susceptible to dielectric breakdown issues at higher input and output voltages. Previous work has revealed that streamer propagation and dielectric overstress are the main culprits in these failures. This paper explores using liquid dielectrics to give a spiral generator self-healing capabilities, thereby extending the lifetime of the generator. Three different coil manufacturing techniques are evaluated to compensate for the lack of mechanical structure resulting from the liquid dielectrics. Electrical characteristics of the spiral generator are calculated and improvements to traditional calculations are suggested for more accurate estimations. These characteristics are validated through benchtop testing with a frequency response analyzer. Operation of a 4-turn liquid dielectric spiral generator is experimentally demonstrated to step up 5.75 kV input voltage to 28.7 kV of output voltage (62% voltage efficiency). Commentary on the self-healing capabilities of the dielectric and viability of this type of design is presented.