Analysis of Semi-Bogie Based Propulsion System Used in Tehran Metro's trains in Degraded Mode of Operation

During the supply process of rolling stocks for metro systems, the propulsion system of trains in terms of separate power and control scheme should be selected based on the Reliability, availability, maintainability, and safety (RAMS) parameters along with some expected indexes in operation plan. This means that, in addition to undeniable control and operation advantages of a train that are equipped with the bogie-based propulsion system, the performance of the train is very important when an inverter module or each propulsion system's component fails, and therefore it should be considered to choose the propulsion system type. Now, a technical grading of propulsion system types can be made from the point of origin, which is a car-based type with the minimum advantages of operation, to the point of destination, which is a bogie-based type with the maximum advantages of operation. Therefore, the semi-bogie-based type that has been applied in Tehran metro trains with one common DC link, input protection circuit, and control is located in the middle of this grading. However, the definitions of the above-mentioned propulsion system types are presented at the beginning of this paper. In order to clarify the functional behavior of a semi-bogie-based type in a degraded and faulty mode of operation to determine its exact position in the above-mentioned grading between the first two types, some investigation will be done based on the simulation in MATLAB, and the results will be presented.