Several modified quasi Z-source dc/dc boost converters are presented. These can achieve soft-switching by using a clamp-switch network comprised of a diode, a capacitor, and an active switch connected across one of the inductors of the Z-source network. In this way, ringing at the transistor switching node is mitigated, and the voltage at the turn-on of the transistor is reduced. Even a zero voltage switching (ZVS) of the main transistor is possible if the capacitor in the clamp-switch is adequately chosen. The proposed circuit structure and operating mode are described and validated through simulations and measurements on a low-power prototype.
