66 / 2020-03-24 13:35:43

8-Stage Travelling Voltage Adder: EM-Model and Simulation

linear transformer driver,travelling voltage adder,magnetic core,EM simulation,triggering sequence

全体主题 > 磁约束聚变/磁驱动聚变

Fast linear transformer driver (LTD) is currently the most promising approach as the prime power source technique of pulsed-power driven Z-pinches. In general, magnetic cores play an important role in the isolation and voltage coupling in LTD systems. Nevertheless, cores bring great expense and extra weight to a machine. Moreover, demagnetization process before each shot contributes to extra complexity of a machine.
The principle of travelling wave voltage addition is proposed and a new conception design based travelling voltage adder (TVA) that eliminates magnetic cores in LTD is presented for the first time in the paper. The conception design of an 8-stage TVA module is presented. Three-dimensional structure, circuit-field coupling electromagnetic (EM) model, parameters and simulation results are introduced in this paper. Each stage consists of one triggering brick and 19 main bricks. The metal rods for current circulating in LTD is replaced by nylon rods. Shielding electrodes are added in each stage to improve electric field distribution.
In EM model, fundamental brick of two capacitors and a gas switch in series was modeled as a current path with an equivalent inductance. Equivalent capacitance and resistance and a time-delayed switch were put in exterior circuits. Suppose that triggering intervals between every two stages are identical and the charging voltage is ±100 kV, peak values of output voltage waveform on a matched load under different triggering sequences remain around 900 kV, rise time ranges from 175 ns to 75 ns. Model results demonstrate efficient voltage addition in waterline and the feasibility of cancelling magnetic cores.