Research And Simulation Of Three-Phase Auxiliary Inverter Control System

With the all-round development of domestic rail transit business, the train’s related equipment demand gradually increased. The huge market demand makes the research of train’s auxiliary power supple electrical equipment carrier of the auxiliary inverter more meaningful. This paper selects the train’s three-phase auxiliary inverter as the research object and focuses on its main control algorithm and software implementation. The main work of this paper are as follow:(1) This paper designed the entire system of three-phase auxiliary inverter and analysis the main circuit of it. The system design has specified the system’s whole structure and the function of every module unit clearly. The circuit partitioning is completed mainly by the analysis of three phase auxiliary inverter, which has confirmed that the main circuit is consisted of DC/DC converter and DC/3 AC three-phase inverter. The work logic and ideal waveform of the circuit are also analyzed in this part.(2) The DC/DC converter control system is designed and analyzed, and a structure of "input serial, output parallel" and the three-loop control strategy of the DC/DC converter are determined. The input grading loop and output double loop of the three-loop control strategy are confirmed to be designed independently through the decoupling analysis. The equations of controller parameters are also calculated in this part and the simulation in MATLAB have been carried out to verify the performance of the controller.(3) The DC/3AC three-phase inverter control system is designed in this part. A mathematical model under three phase stationary coordinate system and synchronous rotating coordinate system is established firstly. Secondly, the voltage and current double closed loop controller in three-phase inverter is designed and the equations of controller parameters are calculated using the pole-placement method. Finally, a system control model under synchronous rotating coordinate system is selected, and the simulated model based on SVPWM control is built to verify the performance of the controller.(4) Design for the software system of three-phase auxiliary inverter. Firstly, the process of the main module in the software system is designed, which contains the overall framework of the program, task process module, system state machine fault detection and protection module and data acquisition module. Secondly, the system control algorithm is digitalized. And the software design of the control algorithm is accomplished finally, which program for the main functional module of the software and the algorithm process.(5) Simulation and prototype test of the three-phase auxiliary inverter system are performed in this part. The mainly simulation task is to verify the correctness of the separately designed controller in the cascade system under operating conditions, analyze the influence between the front stage and the rear stage, and simulate the process of load switching and motor soft start. System prototype test mainly focuses on the performance of the control system in actual situation and proves the validity of the controller and the system performance.