High-Current Compact FCG Seed Source Implementing Solid State Switching

Flux Compression Generators (FCGs) are some of the most attractive sources of single-use compact pulsed power available today due to their high energy density output and mobility. Driving FCGs requires some seed energy, which is typically provided by applying a high seed current, usually in the kilo-Ampere range for mid-sized helical FCGs. This initial current is supplied by a high-current seed source that is capable of driving an inductive load. High-current seed sources have typically been comprised of discharging large capacitors using spark-gaps and over-voltage triggering mechanisms to provide the prime power for FCGs. This paper will discuss a recent design of a self-contained (battery powered with full charge time less than 35 sec), single-use Compact Seed Source (CSS) using solid state components for the switching scheme developed at the Center for Pulsed Power and Power Electronics at Texas Tech University. The CSS developed is a system (0.007-m³ volume and weighing 13 lbs) capable of delivering over 250-J (~10 kA) into a 6-muH load with a trigger energy of micro-Joules at the TTL triggering level. The newly designed solid-state switching scheme of the CSS incorporates off-the-shelf high-voltage semiconductor components that minimize system cost and size as necessary for a single-use application. An in-depth and detailed evaluation of the CSS is presented primarily focusing on the switching mechanics and experimental characterization of the solid state components used in the system.

I. Introduction

While flux compression generator (FCG) performance is relatively independent of how the initial energy is supplied to the FCG, the overall system performance from prime power to pulsed power output depends on the efficiency of the seed source. Previous designs have been reported in the open literature that utilize the use of battery driven seed sources [1], [2], [3]–. Though successful in the functionality, these designs fail to charge the seed source in an adequate time for generation of a High Power Microwave (HPM) pulse in an on-demand application, exceeding five minutes in charge time for the seed source. Other systems have showed a much faster charge time for the seed source, but were for much smaller systems and with load energies of only 6 J [2]. Previous designs that have achieved a high energy output along with fast charge times have typically been oversized to be practical in a compact design as is the goal for the work presented here, weighing several 10 kg for a maximum stored energy of 725 J [3].