Research On The Control Of The Three Phase Inverter In The Electric Locomotive's Auxiliary Convertor

With the continuous development of the modern power electronics technology, electric drives act as extremely prominent function in modernization. In order to meet the requirements of high performance, environmental protection and energy conservation, AC variable-frequency speed regulating system with the special advantage is replacing the conventional direct current speed regulating system gradually. Thus AC variable-frequency speed regulating system makes the important role in the electric drives. The auxiliary inverter of electric locomotives is used to provide power for the fan load which cool the main circuit and offer wind regime for the air brake system. Its working status is critical for the stability and safe operation of the locomotivesThis paper not only expounded the structure of the main circuit and the devices selection of the 200km/h electric locomotive inverter system, but also illustrated the study and implementation of electric locomotives auxiliary inverter control system based on DSP .Making use of the Texas Instruments'TMS320LF2407A that is special chip for motor control. And we designed the motor driver and power source module.This paper expatiated that the mathematics models of AC motor is higher order, non-linear and closed coupling,multivariable input-output system. And introduces the principle and the algorithm of Sine Pulse Width Modulation(SPWM),opened-loop Space Voltage Pulse Width Modulation Control(SVPWM).Finally, realized the control strategies of variable-frequency speed regulating using assembly and C language. I also designed the DSP's minimum system for the sake of realize the system practicability.The paper shows the experiment results and wave-line analysis compared with the MATLAB/SIMULINK simulation. According to the test, the variable-frequency speed regulating system not only can regulate speed smoothly in 5～50Hz scope, but also have good dynamic and static performance. The test results confirmed that the design of variable-frequency speed regulating system is effectual and feasible.