CONTROL DEVICE AND METHOD FOR DETERMINING THE ROTOR ANGLE OF A SYNCHRONOUS MACHINE

A method for determining the rotor angle of a synchronous machine. In one implementation, the method includes generating a multiplicity of pulse-width-modulated drive signals for the phases of an inverter feeding the synchronous machine depending on a voltage to be fed into the synchronous machine, changing the pulse width modulation frequency of at least one drive signal of the multiplicity of pulse-width-modulated drive signals, with the result that the duration of the switching states of the inverter in which an active voltage phasor is output is extended in order to generate a switching pattern for the phases of the inverter, driving the inverter with the generated switching pattern, determining one or more of neutral point potentials at the neutral point of the synchronous machine during driving of the inverter with the switching pattern, and calculating the rotor angle of the synchronous machine depending on the determined neutral point potentials.