Analysis of a current fed voltage multiplier bridge for high voltage applications

Abstract

The power density of high voltage DC power supplies can be optimised when diode-capacitor voltage multipliers are applied. A further improvement can be achieved by feeding the multipliers by high frequency series resonant converters. Ideally, the series resonance is formed by the leakage inductance of the transformer and the capacitors of the multiplier. In this case the multiplier is practically supplied by an AC current. The performance of a current fed voltage multiplier bridge topology with an arbitrary number of stages and capacitors has been analysed for steady state conditions. This concerns the voltage and current stress of the voltage multiplier. Moreover, an equivalent circuit of the current fed VM has been found. It turns out that a current fed VM can be described by a standard full bridge rectifier, a resistor and a series capacitance. The properties of the equivalent circuit as well as the maximum stress values can be calculated by straight forward formulas which are presented in the paper. The novel theory meets the results of a detailed PSpice simulation and it has also been confirmed experimentally.