Application of speed sensorless control to railway traction field

We have developed a novel drive system without using speed sensors in the railway traction field. In this time, we carried out some running tests in the field using an actual train to verify the total stability and performance of the proposed system. Especially, these experiments were executed under 4 induction motors driven in parallel by only one VVVF inverter. It is concluded that the proposed system was so stable in all speed regions including wide flux weakening region using 1 pulse mode, and it's adhesion control performance was almost at the same level as the conventional drive system.