Research On Voltage Control Method Of Electrical Locomotive Auxiliary Inverter

Electric locomotive auxiliary inverter is one of the important parts of electric locomotive, mainly provide locomotive traction fans, pumps and other auxiliary equipment with stable AC voltage. Its running condition will directly affect the stable operation of the locomotive, so the auxiliary inverter technology is one of the key technologies of electric locomotives.In this paper, The project" Electric locomotive auxiliary inverter control system design" is the background, it researchs electric locomotive auxiliary inverter voltage control method and the auxiliary inverter control system.According to working principle of the electric locomotive auxiliary inverter and the load characteristic of the auxiliary equipment, the special VVVF control strategy (U/f2=C) is used.In order to better output voltage, PI controller is used to Closed-loop control of output voltage. The influence of the DC voltage fluctuation, filter, dead-time to the output voltage is analyzed, also the corresponding measures are put forward. Second-order LC low-pass filter principle is introduced, according to the transformer parameters, the suitable filter capacitor value is designed. According to the actual situation of electric locomotive auxiliary inverter system, the electric locomotive auxiliary inverter was established the simulation model on Matlab/Simulink, auxiliary inverter of voltage control method in the simulation experiment was carried out.To get a better output voltage harmonics effect, Selected harmonic elimination PWM method is used in this paper. The mathematical model of SHEPWM is set up. Compared with the SPWM, SHEPWM is used in the paper. Due to equations of switching angles is the transcendental equation, compared to various methods of Approximated implementation, curve fitting approximation is used to real-time calculation of SHEPWM on DSP. According to distribution characteristic of SHEPWM switch angles, the modulated waves per15°as a part, the carrier is used to generate pulses.In this paper, the auxiliary inverter control system research and development functions is carried out, such as serial communication, CAN communication, fault processing logic, AD sampling.The electric locomotive auxiliary inverter voltage control method and modulation strategy in this paper have been carried out on domestic high-power electric locomotive, and passed all of the experiments, the experimental results achieved electric locomotive auxiliary inverter experiment outline requirements.