Braking Energy Recovery of Intra-City Trains Using Power Transmission Through Induction Coupling: A Case Study of Isfahan Metro

The problem of air pollution caused by the use of fossil fuels in transportation has caused the development of the electric transportation industry. The intra-city train (metro) is the most economical and widespread means of electric transportation, which is considered one of the ways to solve the problem of traffic and air pollution. Due to the lack and limitation of energy production resources and the high cost of energy production, there is a need to implement energy consumption management in the metro industry. Recovering electrical energy and reducing power losses in the urban train braking system is one of the necessary and important methods for optimal energy consumption. With the help of braking energy recovery system, the inertia of the train, which is converted into heat in friction brakes, can be converted into consumed electricity. In dynamic braking, the kinetic energy of the wheel is converted into electrical energy using the generator mode of the train's traction system when braking is applied, and this energy is usually wasted in braking resistors. In this paper, braking energy recovery of metro trains using power transmission through inductive coupling is presented. This structure is presented to optimize the braking energy of the train, which has been simulated and investigated as an example in the Isfahan subway. The proposed model consists of a two-way power electronic circuit. The primary circuit consists of a full-bridge inverter installed inside the train connected to the primary coil, and the secondary circuit is a full-bridge inverter circuit connected to the secondary coil, which is installed in subway stations. The primary and secondary connection is established by induction coupling between the primary and secondary coils, and the braking power is transferred to the outside of the train. The studied system model is implemented in Simulink MATLAB environment and the simulation results as well as the mechanical brake diagram and the traction power diagram of the train are shown.