Grid-Connected Technologies Of Auxiliary Inverters For Rail Vehicles

As an important part of the rail train power supply system,the auxiliary inverter plays an important role in the normal operation of the train.In order to improve the reliability and redundancy of the auxiliary power supply system,the grid-connected power supply technology of the auxiliary inverter of the rail train is studied.First,the inverter single-machine control technology is studied to meet the stable operation and output waveform quality of the auxiliary inverter single-machine system.To ensure a good foundation for the reliable operation of the auxiliary inverter gridconnected power supply system.The topology of the inverter circuit is designed.The power relationship between the three-phase transformer and the filter circuit is analyzed,and the state space equation of the main loop is derived.Based on the analysis of space vector modulation technology,a voltage closed-loop control strategy based on coordinate transformation is proposed.What’s more,current feedforward is added to improve the output adjustment capability of the inverter for dynamic processes.Based on the DSP and FPGA engineering application background,the system control and protection are digitalized.Aiming at the shortcomings of traditional grid-connected power supply using threephase phase-locked loop,based on second-order generalized integrator(SOGI),a new type of single-phase phase-locked loop technology is implemented.The output power characteristics of the inverter and the traditional droop control theory to analyze.For the defect of the slow dynamic response of proportional droop,the differential droop component is added to improve its dynamic responsiveness.In order to improve the accuracy of the power calculation of the track train under complex load conditions,the instantaneous power calculation method in dq coordinate system is proposed.By modeling the power flow of the vehicle,a power control loop of the grid-connected system is designed to improve the power sharing effect.For the secondary loop current of the carrier-free auxiliary grid-connected system,the auxiliary converter with power frequency transformer is analyzed.The carrier cycle equal-synchronization method is proposed to realize the inverter carrier self-synchronization.MATLAB / Simulink simulation model is built for relevant simulation verification,Perform relevant experimental verification on the auxiliary power supply system experimental platform.Simulation and experimental results show the feasibility of the stand-alone and grid-connected control methods.55 figures,6 tables,61 references.