A novel unity power factor correction principle in direct AC to AC matrix converters

Modulation strategies for a matrix structured direct AC-to-AC power converter are developed. In principle, for a given set of input three-phase voltages, any desired set of output voltages can be synthesized by the suitable toggling of matrix switches. A mathematical proof that the direct AC-to-AC matrix power converter can operate with unity power factor was provided by analyses of the switching matrix approach. A symmetric and antisymmetric switching strategy was developed for synthesizing an output voltage vector from an appropriate combination of input voltage vectors. Unity power factor operation was achieved by using the combined symmetric and antisymmetric modulation strategy. This combined algorithm enables unity power factor operation without current sensing and current control