Design And Research On The Experimental Platform Of Traction Inverter Based On DSP

Today,the railway is not only a very important infrastructure of the country,but also the key of the national economy,which is the most convenient mean of mass transportation.Electric traction AC drive system is the core of high speed EMU,and the system consists of the pantograph,the main circuit breaker,traction transformer,traction converter,three-phase AC traction motor and gear box and so on,in which the traction converter is the priority among priorities of traction converter energy conversion device.The main task of the traction converter is to receive the AC current from the traction transformer,and then to complete the AC / DC conversion process.No matter the rectifier or inverter,the PWM control strategy is indispensable.For the control strategy,SPWM and SVPWM,two different control methods are widely used.According to the working principle of traction converter,a hardware experiment platform was built in the laboratory.It was hoped that in the laboratory environment,the modulation strategy of the traction inverter can be verified on the platform of simulation and experience.The advantage of the platform is that it is convenient for people to do experiment and to observe the result more intuitively.Based on the basic working principle and control strategy of the DSP control chip,the program is compiled in CCS software,and it makes the DSP output PWM pulse.According to the PWM output pulse,the turn-on and turn-off of the IPM internal switch device were controlled and the speed control of the three-phase asynchronous motor was regulated by three-phase output current of the inverter.The traction inverter experimental platform was built by the use of DSP,IPM,the three-phase asynchronous motor,the photoelectric encoder and the other hardware in the paper.The SPWM modulation strategy and SVPWM modulation strategy were analyzed on the platform of Matlab/Simulink.A variety of experiments were performed on the experimental platform,it verified the modulation strategy of invert process SPWM and SVPWM,and came to a conclusion : the modulation strategy of SVPWM is better than that of SPWM.All kinds of problems happened in the experiment were analyzed,and a series of clear methods were obtained to solve the problems.