US Patent 9534882 Device and method for driving a door

To improve the energy efficiency of electrical drive systems for doors, the electric motor is actuated position-dependently, the electrically driven door is disconnected from the supply network in a resting position, a change of position of the door performed in the state of being disconnected from the grid is detected by a position encoder unit that is independently supplied with power by an energy store, and the change of position is used for position-dependently actuating the electric motor after the supply voltage has been reapplied.