| Abstract |
The transport authority of the City of Frankfurt (Germany) ordered twenty light rail vehicles with completely new traction equipment. The cars are driven by eight asynchronous motors which are mounted in the wheel hubs. These motors are fed by four pulse-width modulated (PWM) voltage-source inverters which are equipped with insulated gate bipolar transistors (IGBT). The maximum blocking voltage of these devices is 1200 V. For this reason, the maximum DC link voltage is limited to 750 V. The PWM inverters are connected to the line via input choppers with IGBTs to suit the high line voltage of 750 V DC + 20 % - 30 %. The system can be operated in regenerative braking mode. There are also braking choppers in order to enable rheostatic braking of the vehicle. The complete power electronics is mounted in two containers at the roof of the vehicle. The power semiconductors are cooled by normal water. The aim of this paper is to describe some details of the power electronics and the control strategy of the light rail vehicle for Frankfurt. Further, some interesting hardware aspects are given, especially the advantages of the technology used. This IGBT technology marks a new trend in the field of traction converters for light rail vehicles. |
