Characteristics of brushless and exciterless, self-excited synchronous generators

New brushless and exciterless, single-phase and three-phase synchronous generators are presented, and the analysis of the characteristics and the test results are reported. In the three-phase generator, the stator armature winding is connected electrically with the secondary winding of a transformer. In the single-phase generator, the stator is provided with the armature winding and the exciting power-supplied winding, and the armature winding is electrically connected with the excitation power-supplied winding through a capacitor. In these generators, AC excitation current flows in the armature winding simultaneously with the load current. The ratio between the number of poles made by the load current and that by the AC excitation current is 2 or 1/2. Thus, the generator can be made brushless and exciterless. The rotor of the single-phase generator is provided with a balanced two-phase field winding. The rotor of the three-phase generator is provided with a bridge-type field winding. Circuit configurations for such brushless and exciterless synchronous generators are presented. Steady-state performances of the three-phase generators are analyzed. Experiments for these generators performed on a 2.0 kW unit are reported.< >