A particular application of a high-voltage DC power supply to drive an X ray tube used ‹n an X ray power generator has attracted special interest in medical power electronics. The X ray power generator must have the particular capability to ad.iust its DC output voltages across X ray tube in order to assure the best quality image for each specified pattern of body part. Higher output voltages are required so as to diagnose more dense body parts of all types of bones. and relatively lower high voltages may be adequately used for diagnosing soft tissues of the organs " "
Therefore. in practice, it is more necessary to control the high-voltage DC output voltage across the X ray tube over widely-specified setting ranges by using DC-DC converter. Some effective applications to achieve the high-performances in transient and steady states of a phase—shifted PWM series- parallel transformer resonant DC-DC power convener with a high-voltage high frequency have been previously discussed by the authors transformer for an X-ray power generator"'.
However, the high-voltage transformers used