A study of volume vs. frequency for soft switching converters

The present study is concerned with determining the volume vs. frequency for the 6 kW converters with forced-air cooling. Both circuits have the same physical layout, but one is operated as a zero-voltage-switching/zero-current-switching (ZVS/ZCS) converter while the other is operated as a more conventional phase-shift converter. Since the switching losses are lower for the ZVS/ZCS converter, its optimum frequency is somewhat higher than the phase-shift converter and its minimum volume is somewhat less. Both circuits actually achieve minimum volume below 20 kHz because of the heat sink requirements, and, if both are restricted to operate above 20 kHz, the volume of the phase-shift converter grows much faster than that of the ZVS/ZCS converter as the frequency increases. It is shown that the volume of the heat sink + reactive components at 20 kHz will be about 70% greater for the phase-shift than for the ZVS/ZCS converter.<
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