The present invention relates to a method and a
control system for driving a three-strand brushless, electronically commutated
electric motor (2), wherein a line AC
voltage (UN) is rectified and fed via a slim DC link (8) with minimum DC link
reactance as a
DC link voltage (UZ) to an
inverter (10) that can be driven to supply and commutate the
electric motor (2). A pulsating
DC voltage (UG) initially generated by rectifying the line AC
voltage (UN) is dynamically increased with respect to its instantaneous values by a step-up
chopper (18) in such a manner that the resulting
DC link voltage (UZ) with a reduced
ripple always lies above a defined limit
voltage (U18 / U1) over time. The
control system consists of a network
rectifier (6), a downstream slim DC link (8) with minimum DC link
reactance and a controllable
inverter (10) that can be supplied via the DC link and driven to commutate the
electric motor (2). A step-up
chopper (18) is integrated therein with a controller (20) designed in such a manner that, the pulsating
DC voltage (UG) rectified by the network
rectifier (6) is dynamically increased with respect to its instantaneous values in such a manner that the resulting
DC link voltage (UZ) with a reduced
ripple always lies above a defined limit voltage (U20 / U1) over time. Stray inductances (Ls1-Ls3) of the motor winding heads present in the electric motor (2) are used as
inductor (L) for the step-up
chopper (18).