High repetition rate charging a Marx type generator

Resistive ladder networks are commonly used as the charging and isolation means for Marx type generators. The efficiency is limited to 50% and the charging time is long or equivalently the PRR (Pulse Repetition Rate) is low. The efficiency can be considerably improved by replacing the resistive ladder with inductor elements and the PRR is also improved. In this paper is it shown that by introducing mutual coupling, k, between the two parallel inductors in each stage of the ladder network, the effective inductance during the charging mode is decreased b/sup 1/y a factor of (1-k)/(1+k). Since it is feasible to achieve a coupling, k, on the order of 0.99, this speeds up the charging time by about an order of magnitude compared to uncoupled inductive charging. During the erected or discharge mode the inductors must provide isolation between stages and must not excessively rob energy from the energy store. The mutual coupling is beneficial in two ways. During the erected or discharge mode, it is shown that the effective inductance of the ladder elements are actually increased by a factor (1+k). The Marx switches cause a re-arrangement of the coupled inductors from parallel during the charging to series during the discharge modes. This results in a much faster charging time, by reducing the effective inductance by (1-k)/(1+k); while providing an effective isolation inductance that is (1+k) greater than the uncoupled value. A practical design of the coupled inductor implementation and modeled simulations of the performance are compared to uncoupled and resistive charging.