Sensorless starting of horizontal axis washing machines with direct drive

This paper describes problems of the sensorless starting of horizontal axis washing machines with direct drive and proposes solution, which was experimentally verified. H-axis washing machines have very difficult conditions for the drive starting, especially at full load. Inertia of the tub and water, torque from the laundry make load torque at starting higher than rated one and sometimes even higher than the maximum torque of the motor, which makes sensorless starting extremely challenging task. This paper suggests modified open-loop starting, where control system is closed shortly after beginning at low speed and rotates the drum until laundry restructuring. To ensure proper work of the sensorless algorithm at low speed an additional method for the drive parameters estimation has been proposed and verified by the experimental results.