Double-field orientation of unity power factor synchronous motor drive

There is proposed a vector control structure for wound-excited synchronous motor drives fed by voltage-source inverter with feed-forward voltage pulse-width modulation, working at unity power factor, which combines the advantages of two types of field-orientation procedure, i.e. stator-field orientation and control for power factor control, and rotor-position- or exciting field-orientation for generating the voltage control variables and self-commutation.