Wheel Slip Suppression Control Method Using Traction Motor Current Information of EMUs Driven by Multiple Traction Motors without Speed Sensors

As for the Electric Multiple Unit (EMU), the system to drive parallel-connected dual induction motors, as traction motor, controlled by one inverter is generally adopted. Nowadays, the induction motors control method without speed sensor is widely used. This paper describes the development of a traction motor control method which could suppress a wheel-slip by detecting it earlier and with smaller amount of torque drop than the conventional method, by focusing the amplitude difference between each traction motor current vector (current difference), for EMUs driven by the parallel-connected two traction motors without speed sensor equipped in the bogie. To verify the effectiveness of the developed control method, we performed the running test with water sprayed using a test EMU. As a result, the average EMU train acceleration in the running direction was increased by more than 5% and the maximum fluctuation width of the longitudinal vibration of the car body was reduced by half, as a result, the ride comfort was improved.