A Study on the Mixed Use of Power Conversion Elements of Propulsion Control Devices in Railway Train

A study is under way to apply the main power conversion element of the C/I device, the propulsion control unit of variable voltage and variable frequency (VVVF), to the electric vehicle by changing it from gate turn off thyristor (GTO) to insulated gate bipolar transistor (IGBT). In an early study, a combination of GTO and IGBT was tested on electric vehicles. The IGBT method was applied to 1 coach and the GTO method was applied to the remaining coaches. As a result of the test, a lack of traction force occurred due to an imbalance in output current. This phenomenon was determined to be caused by differences in the operational characteristics of the two types of power devices. This is due to the different response performance of the IGBT inverter vehicle and switching signal of the controller that drives the existing GTO inverter. When two power devices are used in a train, it is necessary to match the response performance between coaches. Interface board was manufactured and installed on the coach with IGBT and tested. The interface board is designed to have the characteristics of matching signals between the controller and the gate drive unit (GDU). As a result, the same switching response performance was achieved between GTO type and IGBT type coaches. The performance of using a mix of two power devices was verified. Therefore, normal driving performance and comfortable ride were maintained during the operation of the train.