Grid-connected And Energy Storage Recovery System Of Locomotive Internal Combustion Engine Test Output Electric Energy

Although China ’s rail transit has entered the era of electrical high-speed,but in our country,many remote and backward,special climate,lack of electricity areas and factories and mines on the line still use diesel locomotives.As the core power plant,the internal combustion engine is inseparable from a large number of internal combustion engine performance and reliability tests in the process of technical research,product development,manufacturing,product maintenance and quality inspection.Due to the high power of locomotive internal combustion engines,a large amount of energy is consumed during the testing process.Usually,the electrical energy output during the testing is absorbed by water resistors,and the output energy is not effectively stored and fully utilized,resulting in serious waste of resources.In order to recover this part of the electric energy,make it fully used by the factory load,and improve the utilization rate of the recovered electric energy,this dissertation proposes a solution to the electric energy recovery system of the locomotive internal combustion engine test output based on the combination of grid connection and energy storage mode.Through modeling and simulation on the MATLAB/Simulink platform,the corresponding analysis and verification are made.In this dissertation,by reading a large number of domestic and foreign energy recovery technology and internal combustion engine test energy recovery technology related literature,a variety of energy recovery technology for comparative analysis and research.Combined with the load power of the test station,the output power of the test internal combustion engine and the characteristics of the energy storage device,the internal combustion engine test energy recovery technology scheme combining grid-connected energy feedback and super capacitor energy storage is selected,and the overall structure and operation mode of the locomotive internal combustion engine output energy recovery system are analyzed and designed.In order to carry out the research project,the first step is to complete the construction of a simulation model for the test unit,which includes a simulation model for the diesel engine and its governor,a simulation model for the synchronous generator,and a simulation model for the generator excitation system.And a sudden increase and decrease in output load test was conducted to verify the effectiveness of the test unit model.Secondly,in order to meet the needs of grid connected energy feedback and supercapacitor energy storage,it is necessary to convert the three-phase AC output of the test unit into stable DC power.Therefore,a PWM rectifier in the energy recovery system has been designed.In order to improve the dynamic stability of the rectifier system,the voltage outer loop and current inner loop control strategies based on constant speed approaching rate Sliding mode control are adopted.Through modeling and simulation,compared with traditional PI control,the overshoot and stability time achieved good results during rectifier startup and input voltage changes.Then,a grid connected energy feedback system was designed to achieve the grid connection of the experimental unit’s output energy.In response to the problem of instability caused by the resonant peak of the LCL filter,an active damping current inner loop with capacitive current feedback was adopted to suppress the resonant peak and improve the quality of the grid connected current.In addition,in order to track the active power of the factory load,a power outer loop was designed based on instantaneous power theory,achieving control of the output active and reactive power of the grid connected energy feedback system.Finally,this dissertation designs a supercapacitor energy storage system.In terms of controlling the bidirectional DC/DC converter,the reference current at the expected charging and discharging power is calculated based on the changes in the output power of the test unit and the load power of the factory area.By utilizing current closed-loop control to track the reference current,the charging and discharging power of the supercapacitor is adjusted to achieve a reasonable allocation of recovered electrical energy and effectively utilize it.