Intelligent magnetic amplifier controlled soft-switching method for amplifiers/inverters

This paper proposes a simple, efficient soft-switching method for power switching converters. Soft switching of the DC/AC H-Bridge converter is realized by paralleling two auxiliary switches and a magnetic amplifier with the load. The auxiliary switches are turned on at a predetermined time before the commutation of the main switches. The magnetic amplifier then automatically determines the necessary amount of redirection current to ensure soft switching of all switches under any load conditions. This method requires no expensive sensors or complex control circuitry. It is ideal for class-D audio power amplifiers where the load current is widely changing. Further applications include DC/DC converters, motor drivers, UPS, communication, and space applications where high efficiency, low EMI and small size are crucial.