Investigation of the waveform quality of a kA-level rectangular pulse generator based on pulse forming network

Pulse forming networks (PFNs) are widely used to generate high-voltage, short-pulse width rectangular pulses. However, certain applications, such as pulse laser driver systems, require high-current, long-pulse width outputs, for which there remains limited research on PFN. This paper focuses on the investigation, optimization, and design of a high-current, long-pulse width PFN. The complex method was employed to optimize the inductance parameters in the PFN, effectively reducing the output overshoot and ripple. Considering the impact of the inductance at each position on waveform quality and the difficulty of component selection, a simplified engineering optimization method was adopted, where the first-stage inductance was significantly changed while keeping the inductance in the other stages the same. The causes and influencing factors of flattop droop during high-current, long-pulse generation were systematically analyzed. The internal resistance, especially from the wire inductors, was the main cause of flattop droop. Building on these findings, targeted design improvements were implemented to maintain high waveform quality under high-current, long-pulse conditions. A rectangular pulse generator based on PFN was subsequently developed, achieving rectangular pulse outputs with the voltage/current of 201.5 V/1007.5 A, current droop of 7.56%, adjustable pulse width from 30 to 219.10 μs, and maximum repetition frequency of 110 Hz. This paper demonstrates significant advancements in PFN performance for high-current, long-pulse applications.