Energy efficiency optimization and energy recovery control strategy for urban rail vehicle traction systems

Traction energy consumption is a major part of the total urban rail energy demand, and in view of the fast expansion of urban rail systems, the traction energy performance plays an increasingly important role in operating cost and environmental burden. This paper studies energy saving optimization and energy recovery control strategies for urban rail vehicle traction systems. It studies the energy flow features and main energy consumption links in traction system, creating a system energy consumptive model to assess performance of existing operating modes. An energy efficiency improvement strategy is presented by employing the high-efficiency motors and converters, optimizing the power system planning, and modifying operational plans. For braking energy recovery, a regenerative braking control strategy and energy distribution algorithm are developed to enhance the recovery efficiency and reduce the waste of energy. Simulation studies and practical operational examples confirm that these strategies are effective to save energy and improve the energy recovery rate. The test results show that the simultaneous design of energy saving and power recovering integrated control can effectively improve performance of the traction system, and realizing it is a reliable technical solution to save energy and reduce emissions in urban rail traffic.