Reliable electric brake for a synchronous engine

The invention relates to a method for reliably controlling a braking torque of a drive system (1). In order to be able to reliably control the braking torque, it is proposed that the drive system (1) has a synchronous machine (2) and a changeover apparatus (3), wherein the synchronous machine (2) has phase connections (20), wherein the changeover apparatus (3), in a first state, connects the phase connections (20) to one another in such a way that a first braking torque (MBr1) is produced at the synchronous machine (2) and, in a second state, connects the phase connections (20) to one another in such a way that a second braking torque (MBr2) is produced at the synchronous machine (2), wherein the changeover apparatus (3) changes over between the states in such a way that a prespecifiable braking torque (M*) is produced at the synchronous machine (2) on average over time, wherein, in order to produce the first braking torque (MBr1), the phase connections (20) of the synchronous machine (2) are short-circuited,