| The catenary of urban rail transportation overhead in scenic spots or downtown will bring visual pollution. What’s more, the braking energy of the traditional urban rail train which using dynamic braking resistors is wasted as the form of heat. This paper relies on the key project of National Eleventh Five-Year Plan:"Low-floor light rail vehicle traction driving control technology and equipment development" and its following topic:"Power battery applied research-traction and power battery charge and discharge control system development" to achieve the goal of realizing on-board power battery energy storage. In order to achieve the goal of making the train run without catenary lines and absorb the regenerative braking energy, this paper works around the main circuit control strategy of the bidirectional DC/DC which cooperates with running of the train.Firstly, this paper puts forward the energy and the charge-discharge power requirements of the energy storage system according to the train load characteristics in the areas without electricity. Because of the forces exerting on train during accelerating and braking is inconstant, common calculation methods cannot meet the traction and power consumption calculation, so this paper use the segmented recursive method. Choose the Li4TisO12battery as the energy storage element by comparing the capability and charge-discharge power demand of energy storage system. Carry out Li4TisOi2power battery capacity configuration according to the application of energy storage systems, and analyze the charge-discharge characteristics of power battery.Then design the main circuit and control system of the energy storage system. Compare choose Buck/Boost bi-directional DC/DC converter as the main circuit according to the demand of energy storage systems and use a direct PWM drive mode. Design the core components of the main circuit according to the main technical parameters of the main circuit. Design control system based on function and module.Based on analyzing the requirements of the energy storage system and the designing of the main circuit, study control strategy of the energy storage system dividing into two patterns:with catenary charging and without catenary operation. According to the characteristics of Li4Ti5O12battery, in the case of catenary charging mode control strategy using the inductor current loop. In the pattern without catenary operating mode the main purpose of energy storage system is to stabilize the intermediate DC voltage. In order to control the battery charge-discharge current and improve the ability to deal with the load mutation of the energy storage system, under without catenary mode use DC voltage outer loop inductance current inner loop with a load current feed forward control strategy. Establish simulation model in MATLAB, and carry out the simulation on the control strategy.Finally, build an energy storage system prototype; finish various functions of experiments and tests of the energy storage system in laboratory platform and Changchun light rail. In the laboratory platform carry out slow and fast charging, load mutation and current two-way flow experiments; verify that the main circuit and control strategy have been designed correctly. The main tests in Changchun Light Rail include basic traction braking performance, maximum traction and braking performance, emergency braking performance, high and low SOC braking traction performance and endurance tests. Test results show that the performance of the storage system can meet the design requirements.The simulation experiments and field test results show that the hardware and control strategy design of the energy storage system is reasonable; the technical indexes meet the design requirements. |
PDF Full Text Request