This paper presents the steady state and resonant current analysis of a Forward-Flyback Voltage Multiplier operating in discontinuous conduction mode. The operation stages are approached, taking into account the resonant current. The static gain and the conditions for the operations modes are obtained. A sinusoidal approximation is proposed to represent the resonant current with respect to the number of stages, voltage multiplier capacitors and leakage inductance. The characteristics of voltage sharing among capacitors, that allows the use of small voltage components, and the high-gain with reduced turns of the transformer are verified. Bench tests were made for a 200 V/2000 V prototype, from one to five stages, highlighting the overall circuit effects for a 200 W output power. Obtained waveforms for different number of voltage multiplier stages validate the theoretical and simulated results, making this converter an alternative to isolated DC/DC systems where the output voltage must be higher than the input voltage.

DCM forward-flyback converter integrated with a 5-order cockcroft-walton voltage multiplier: A steady-state and resonant current analysis

The article describes the phenomena occurring in the Half-Wave Cockcroft-Walton voltage multiplier when it is supplied through a transformer by an inverter with a rectangular shape of output voltage. The frequency of the inverter output voltage was selected so that a series resonant phenomena occurs in the system. They are caused by the presence of voltage multiplier capacitors and transformer leakage inductances. In the article the characteristics and waveforms of voltages and currents obtained by simulations are presented. The results of simulations were used to build two prototypes with maximum powers of about 60 W and 160 W and a 40 kV output voltage.

The Cockcroft-Walton voltage multiplier fed by an inverter in which the series resonant phenomena were used

Design and implementation of a 10 kV/10 kW high-frequency center-tapped transformer

The paper presents a novel converter for a medical X-ray machine application. A resonant, current fed inverter is proposed. The high voltage transformer step up ratio is kept very low to reduce the effects of its leakage inductance and other non-idealities. Moreover this leakage inductance and the parasitic capacitance of HV transformer and switches are used as resonating components for attaining a soft switched conversion. The switches are soft switched with ZCS, which works over a wide load range. A set of Cockroft Walton multiplier is employed on the secondary side of the transformer accomplishes the final output. The converter operates at 100 kHz frequency with overlap time switching to achieve 100kV and 2.5 mA required by the X-ray machine. A very systematically elaborated analysis for selection of every discrete component in this particular topology is discussed in this paper.

S. Nachiket Choudhary

Papers

High gain, naturally clamped Dc to Dc converter for X-ray application