Research And Implementation On Parallel Technology Of Auxiliary Inverter In Hybrid EMU

The auxiliary power supply system,as an important component of the EMU,has a tremendous impact on the normal operation of EMU.In order to improve the reliability and redundancy of the auxiliary power supply system,the parallel control technology of the auxiliary inverter is studied in this paper.The stable operation and the output voltage quality of stand-alone auxiliary inverter is the basis of reliable operation of parallel system.In this paper,the control method of the stand-alone auxiliary inverter is studied.The topology of auxiliary inverter in hybrid EMU is introduced and he models under different coordinates are established.The three phase nonlinear load such as air conditioners and battery chargers in hybrid EMU is analysed.The PIR control method under dq rotating coordinate is applied.The PI controller ensures the stand-alone inverter system having a good dynamic characteristics and guarantees the output voltage tracking the given voltage without static error.And the resonant controller eliminates the voltage distortion caused by the nonlinear load.Discrete methods of resonant controller is studied and compared,and the modified tuison method is chosen to eliminate the voltage distortion and improve the quality of the output voltage.In the parallel inverter control strategy,different power calculation methods are compared,and the optimal power calculation method is selected.The power characteristics and traditional droop control theory are analyzed.The resistive droop method which is more suitable for the auxiliary power supply system in hybrid EMU is introduced and the differential droop coefficients for improving the dynamic characteristics are adopted.And the virtual impedance technology is added to improve the current characteristics.The principle of three-phase synchronous rotating coordinate phase-locked loop is presented.Then the method of single-phase synchronous rotating coordinate phase-locked loop is used to realize the phase synchronization of parallel inverter system.The cause of the switch circulation in parallel inverter system is analysed.And the carrier synchronization methods are proposed to suppress the switch circulation.The MATLAB/Simulink simulation model is established and the experimental platform is based on the auxiliary inverter system of hybrid EMU.Simulation and experimental results verify the feasibility of the proposed control metod of stand-alone system and parallel system.