| 摘要 |
PROBLEM TO BE SOLVED: To suppress spike voltage produced during commutation in a frequency conversion circuit and reduce circuit loss, by connecting a capacitor to a transformer in the direction in which the electric charges in the capacitor are regenerated to the transformer according to the polarity of the output of the transformer. SOLUTION: Immediately before the time t1 at which the voltage e2 of the secondary side of a transformer 3 becomes zero, a transistor 43 is in conduction, and a capacitor 709 is charged to a voltage two times the peak value Ed of the voltage e2 through the transistor 43 and diodes 705, 708. At time t1 , the voltage e2 is zeroed. Since the capacitor 709 has no discharge path, however, the voltage of the capacitor 709 is maintained. At the time t2 , a transistor 41 is turned off to commutate from the transistor 41 to the transistor 43, but accumulated energy of circuit inductance, such as leakage inductance, of the transformer 3 is absorbed into the capacitor 709 over the path of the diode 707 to the capacitor 709 to the capacitor 706 and to the transistor 43. The capacitor voltage is increased from 2Ed by the amount equivalent to absorbed energy. |
