| 摘要 |
PROBLEM TO BE SOLVED: To improve the conversion efficiency of a three-phase cycloconverter by adding very few circuit parts to a snubber circuit for the cycloconverter and regenerating the energy of a snubber capacitor to electric power during the period based on the resonance frequency with the inductance of a high-frequency single-phase AC power source side. SOLUTION: A snubber circuit 20 is provided with a snubber capacitor 21, a first diode 22, a second diode 23, and an auxiliary switching element 24. When the element 24 composed of a transistor, etc., is turned on, the energy absorbed by the capacitor 21 is regenerated to a high-frequency single-phase AC power source side and the voltage of the capacitor 21 drops to the rectified value of the secondary-side voltage of a high-frequency transformer 12. When the element 24 is turned off, the energy in the snubber circuit 20 is discharged through the second diode 23 so as to suppress the jumping voltage which is generated when the element 24 is turned off. Therefore, the conversion efficiency of a three-phase cycloconverter can be improved. |
