Dual Inverter Controlled Third Harmonic Current Injection Scheme for an Open-End Winding Brushless Wound Rotor Synchronous Machine

The proposed brushless open-end winding machine synchronous machine utilizes a method where a third harmonic current, fed by two inverters, is employed to create and regulate a harmonic magnetic field in the airgap. This leads to self-excitation through voltage induction in a harmonic winding located on the rotor. The open-end armature winding is supplied with three-phase composite currents and a zero-sequence third harmonic current from two inverters, resulting in the creation of the desired harmonic magnetic field. The harmonic winding on the rotor intercepts the harmonic magnetic field generated by the rotor's movement at synchronous speed, resulting in the generation of voltage. When the rotor is not moving, a pulsating harmonic field connects to the rotor's harmonic winding and causes voltage to induce. Eventually, this voltage is used to excite the rotor field windings through a rectifier installed between the harmonic windings and the field windings. The electromagnetic performance and underlying theory are validated by performing 2D finite element analysis using ANSYS Maxwell software.