Patent ID: 8729845

Claim:
A method for controlling a sensorless electric motor, comprising: measuring a motor current and a motor voltage during a sensorless open-loop control mode of operation of the motor, determining a speed and a torque of the electric motor from the measured motor current and the measured motor voltage, computing a moment of inertia of the electric motor and determining a control torque from the calculated moment of inertia, associating the control torque with a torque control value determined by a controller from a speed deviation from a speed setpoint value, and supplying the control torque as a torque setpoint value to a control element for setting the motor current or the motor voltage, wherein during a sensorless open-loop control mode of operation the control element receives as input variable a control torque generated from a predefined moment of inertia, as long as the speed of the electric motor is below a minimum speed.