A class-H amplifier as a generic power source for arc welding

A generic power source for arc welding, based on a class-H design, is discussed and contrasted with other, more common, types of welding power sources. The differences in the performances of a class-H design and the more traditional class-A and switching mode power sources are illustrated and discussed. It retains the flexibility, frequency response, and relative simplicity of a traditional series-regulated class-A amplifier, while improving the efficiency through electronic switching between multiple rail voltage levels. The specific power source presented is capable of delivering up to 45 V at 500 A with a frequency response into several decades of kilohertz. Through appropriate control mechanisms it can be used as a constant-voltage source and a constant-current source, and it can be driven in various pulsing configurations in either of these basic electrical power source modes