Research On High Performance Control Of Locomotive Auxiliary Power Inverter

The auxiliary power inverter is an important component of the locomotive. In order to meet the high reliability, high power and redundancy requirements, in this thesis, we research on dual-loop control of single inverter and parallel inverters without control interconnection.This thesis is based on three-phase two-level inverter bridge and LC filter circuit topology, and uses the double-loop of voltage and current control strategy based on the two phase rotating coordinate to decouple inverter system, the parameters of the filter were quantified analysis. PI controller is selected to design the type I system for current inner loop which has fast dynamic response, and type II control system for voltage outer loop which has high precision. MATLAB simulation shows that this control strategy good steady-state and dynamic performance.This thesis analyzes the droop control principle and circulation characteristics, and shows the double closed loops and power droop control algorithm in two phase rotating coordinates. It analysis the principle of generalized integrator based on second-phase locked loop. The impact of different parameters to circulation is analyzed, and the results show droop control system can be well suppressed parallel circulation. It uses MATLAB simulation model to conduct the simulation of inverter parallel system in specific conditions, and the results show a good steady-state and dynamic performance of the parallel system.Finally, this thesis sets up a laboratory prototype to verify the methods of dual-loop control and parallel inverters without control interconnection. The experiment results show that inverter has good steady-state performance without load or with resistive and inductive load, and the inverter has faster dynamic response when load increases or decreases abruptly. The system still operates normally under certain conditions, and it can meet the high reliability and redundancy requirements of locomotive auxiliary power inverter. It proves the feasibility of the method researched in this thesis.