Abstract: During displacement of an actuating element to a target position, a brushless direct-current motor is driven by a driving commutation pattern derived from rotor position signals. After the target position is reached the brushless direct-current motor is transferred to a holding mode in which it is driven by a commutation pattern providing a required holding torque. In the holding mode the holding current necessary for providing the required holding torque is minimized by an iterative holding current reduction method to a holding current value guaranteeing the required holding torque.

Abstract: A motor control of a motor has a DC circuit with a back-up capacitor and a switching device that can connect a motor to the back-up capacitor. A spring device applies a restoring force to the rotor of the motor when deflected from an idle position. When the DC Circuit feeds energy into the back-up capacitor from a power supply network, a control device activates switching elements of the switching device to adjust an actual deflection of the rotor to a required deflection. When the rotor is deflected from the idle position and the back-up capacitor receives no energy from the power supply network, the control device, supplied with energy by the back-up capacitor, sets the required deflection to the idle position and activates the switching elements such that the motor, upon being restored by the spring device, feeds energy into the back-up capacitor via the switching elements.

Abstract: During displacement of an actuating element to a target position, a brushless direct-current motor is driven by a driving commutation pattern derived from rotor position signals. After the target position is reached the brushless direct-current motor is transferred to a holding mode in which it is driven by a commutation pattern providing a required holding torque. In the holding mode the holding current necessary for providing the required holding torque is minimized by an iterative holding current reduction method to a holding current value guaranteeing the required holding torque.