SUPPLYING A SYNCHRONOUS MACHINE WITH AN EXCITATION CURRENT

A regulating device for a brushless excitation system for supplying at least one excitation coil of a rotor of a synchronous machine with excitation current, having a detection device to detect a strength of a magnetic flux; a regulating unit to generate an auxiliary excitation DC current supplied to the main excitation machine by rectifying an auxiliary excitation three-phase current, and to regulate the current strength of the auxiliary excitation DC current such that a magnetic flux generated between the rotor and the stator of the main excitation machine is kept constant independently of the current strength of the excitation current; and an adjusting unit rotationally fixed to a rotor shaft of the synchronous machine to generate the excitation current by rectifying an excitation three-phase voltage generated by the main excitation machine and to regulate the current strength of the excitation current supplied to the rotor of the synchronous machine.