Current Application Status of Electric Traction Technology for Modern Urban Rail Transit Vehicles

(1) Electrical traction system

The electrical traction system is the foundation for the application of electrical traction technology. Due to the fact that urban rail transit vehicles use the third rail power supply method, the overall level of the corresponding electrical traction system is extremely high and must meet certain standards in all aspects. In an electrical traction system, the constant gravitational force of electrical traction must always be maintained within a certain range, usually with a constant traction force of 346KN and a natural traction force of 230.2KN. At the same time, there are certain conditions for the electric oxygen traction of rail transit vehicles, and the basic limitation is that the traction force should change according to the changes in vehicle load, so as to ensure that vehicles in different load states are always in the rated traction state, maintain stable and reliable rail transit transportation, and prevent situations where vehicles cannot maintain the rated traction state during different peak and valley passenger carrying periods. In addition, in order to prevent the impact of electric braking force on the operation level of rail vehicles, it is necessary to ensure that the electric braking properties are suitable and can effectively guarantee the braking speed.

(2) Control system

In the application of electrical traction technology, control is the most crucial part, which can be said to be the key to ensuring the stability, safety, reliability, and efficiency of the entire urban rail transit transportation. The current control of electric traction for rail transit vehicles is based on computer control systems, which use computer network technology, sensing technology, etc. to achieve real-time monitoring of vehicle operation. At the same time, the entire rail transit system can be controlled locally through information technology control in the control center, and self inspection and self-control can also be achieved to ensure the maximum stable operation of the system. With the support of a tightly connected electric traction control system for rail transit vehicles, comprehensive control of the vehicles can ensure that the transportation situation of urban rail transit is fully realized according to expectations and plans, and adjustments and improvements can be made to the parts that contradict the plans and plans.

(3) Main components

In the application of electrical traction technology, three major components are crucial. One is the current collector. The current on the sliding contact line is transmitted to the rail transit vehicle through the collection of electricity, so the collector is the foundation and medium for the application of electrical traction technology. It is installed on the receiving bracket, and the receiving bracket is installed on the rail transit vehicle. With the use of the vehicle, the carbon brush on the current collector moves within the sliding contact line, achieving uninterrupted power supply and promoting stable operation of the vehicle. The capacity of the current collector must match the capacity of the wire, and the current collector often has a certain standard specification. This means that when the capacity of one current collector is insufficient, the capacity can be increased by connecting two current collectors in parallel. The carbon brush of the current collector is made of copper containing carbon based pressure, with good characteristics of toughness, pressure resistance, conductivity, and lubrication, which can meet the traction requirements of urban rail transit vehicles. However, it needs to be replaced in a timely manner after use and wear to a certain extent. The second is the circuit breaker. The circuit breaker mainly plays an emergency blocking role in the electrical traction control of rail transit vehicles. Circuit breakers can reduce the time required for braking segments and achieve emergency braking in a short period of time, effectively ensuring the safety of rail transit transportation, especially in some emergency situations. They have enormous application advantages. The third is interface electrical appliances. The advantage of interface electrical appliances lies in their free matching, which can effectively connect various parts of the electrical traction system of rail transit vehicles. However, during use, it is necessary to ensure that the matching is in place and the electrical quality is good enough.

(4) AC traction motor

The role of AC traction motors in the electrical traction control of rail transit vehicles is beyond doubt. With the expansion of modern urban rail transit transportation scale and increased operational requirements, the corresponding motor traction pressure has increased. It is necessary to continuously optimize and improve the motor to enhance its stability. At present, the AC traction motor in traction control of rail transit vehicles is mainly powered by IGBT inverter, which will effectively replace the heating program in the original motor and meet the requirements of electrical traction control.