I. INTRODUCTION
The number of different types of electronic equipments
that use high DC voltages is increasing since the last decade.
Medical and industrial X-rays, CO2 laser-based systems and
the telecommunications equipments with traveling wave tube
(TWT) are typical examples of these applications [1-6].
A large number of special power converters have been
proposed to supply these equipments [1-6]. The design of
high voltage power supplies presents several problems and
drawbacks that can not be observed in low voltage
applications. Therefore, each particular application requires a
specific solution to achieve the design specification
requirements. Reliability, high efficiency and low cost and
size are the aims that the designer should reach.
The first topologies employed in high voltage power
supplies were based on PWM (non-resonant) converters.
Nevertheless, this strategy presents several problems, many
of then caused by the high-voltage transformers. The large
turns ratio in the transformer increases the effects of the
transformer non-idealities. The principal effects that produce
changes in the behavior of the power converter are voltage
spikes that can damage circuit components and current spikes
respectively originated by the leakage inductance and the
parasitic capacitance formed between windings [7].
The resonant converter is an attractive alternative to avoid
the problems caused by the non-idealities of the high voltage
transformer. In this case, the non-idealities can be used as
integrant part of the circuit, were the leakage inductance and
capacitance of the transformer are used as part of the
resonant circuit components [2-3], [5], [8-9]