Extending the optimization of the rotating transformer brushless excitation to all rectifier modes

Brushless excitation of a synchronous machine has a significant advantage: no slip-rings are necessary. The rotating transformer method is investigated: the excitation machine is a wound rotor induction machine with controllable voltage supply on the stator side. The synchronous machine is excited by a diode bridge, connected to the rotor of the excitation machine. The operation of the system is essentially determined by the commutation of the rotating diode bridge. It has different rectifier modes in such a configuration (possibly long commutation process caused by the variable, possibly lower voltage; larger commutation inductance). With justified simplifications, a model is derived to investigate the operation. The classical converter theory is applicable for the variable voltage, variable frequency supply of the diode bridge. Optimal operation considering the utilization of the excitation machine is introduced, developed and extended to all rectifier modes. The result is a matching rule for the parameters of the system, which can be satisfied by complex design of the system elements.