A method and an apparatus that permit the measurement of the motor average
current directly from the output of the amplifier and filter stage used
for instantaneous dc-link overcurrent protection. As such, only one
amplifier and filter stage is sufficient to provide both the motor
average current and instantaneous dc-link overcurrent protection. The
invention permits the suppression of the amplifier and filter stage that
is typically used to derive the motor average current directly from the
dc-link current.