Nanosecond forming line based on compact power high-voltage pulse capacitors

Specific problems regarding high-voltage pulse capacitors for quasi-rectangular nanosecond pulse formation at a low resistive load are discussed. Such a capacitor could be presented as a ladder-circuit which functions as a strip transmission line discharging to a matched load. The capacitor consists of conventional low inductive capacitor sections. The packages of these sections are connected in parallel by means of plate conductors which form the main (longitudinal) inductance of circuit cells. The inductance of the packages (the transverse inductance) affects negatively the shape of the formed pulse. The capacitor construction is improved by making the circuit cells nonuniform. As a result the negative effect of the transverse inductance could be cancelled. Furthermore, the nonuniform capacitor consists of a half number of the cells as compared with the uniform one and provides the same front and tail steepness and flat-top stability. A numerical calculation technique is developed which could be applied for such nonuniform circuit calculation. The experimental results are in very good agreement with the theoretical behavior and demonstrate the following characteristics achieved with compact nonuniform capacitors: pulse length of 30 ns to 1 ms, front steepness of up to 10¹³ A/s, resistive load of 1 to 10 Ohm, charging voltage of up to 200 kV