Patent ID: 6838841

Claim:
A method of controlling an electronically commutated DC motor, the method comprising: providing a multiphase stator winding having an even number of winding phases parallel to one another; connecting each of the winding phases in series with one of a plurality of controllable semiconductor switches; cycling the plurality of controllable semiconductor switches in a lower output range of the electronically commutated DC motor using a pulse control factor, which is predefinable as a function of a rpm, within consecutive periods when individual ones of the winding phases are energized; and achieving a setpoint pulse control factor required for a setpoint rpm within a selected set range of the pulse control factor by alternating between setting a first pulse control factor that is greater than the setpoint pulse control factor and a second pulse control factor that is smaller than the setpoint pulse control factor, the setting of the first and second pulse control factors being varied over time so that a voltage that regulates the rpm at the setpoint rpm is set across the stator winding as an average over time.