Performance of a Doubly Excited Cylindrical Rotor Brushless Synchronous Generator

In this work, a doubly excited cylindrical rotor brushless synchronous generator is proposed. The machine consists of two-pole excitation winding in both the stator and rotor, along with the four-pole armature winding in the stator and field winding in the rotor. The excitation windings develop the required excitation for the field winding of the synchronous generator and are connected to the field winding in the rotor by a rotating three-phase diode bridge rectifier. However, the excitation winding in the rotor is kept in such a way that the current flowing in the excitation winding develops some extra 4-pole Flux in the core, which in turn boosts up the voltage induced in the main machine armature. Thus, the flux produced by the excitation machine is utilized to develop armature voltage in the main machine(MM). This phenomenon improves voltage regulation and also reduces field current rating of the synchronous generator. In this work, a 5 kVA, 415 V machine is designed and its no load and full load characteristics are obtained from Ansys Maxwell 2D.