| Along with the rapid development of Chinese railway industry, Chinese electric locomotive technology has achieved the international advanced level. In recent years, through the introduction of foreign advanced locomotive technology, creating "HXD" series of high-speed, heavy-duty locomotives, achieved a level of locomotive equipment overall improvement. However, due to the heavy task of rail transport, Chinese SS series electric locomotives still subject to the important task of passenger and freight transport on the railway lines. Therefore, using advanced technology for Chinese domestic electric locomotive technological innovation is also very necessary. Being an important part of electric locomotives, the auxiliary power supply system is the key to ensuring the safety of locomotive main circuit and the comfort of traveling-environment. Therefore, the operating conditions of auxiliary power supply system have a great impact on the overall operation of the locomotive.This paper has studied the SS4B electric locomotive auxiliary converter, and the SS4B electric locomotive auxiliary power supply system is upgraded. Then, we replace the split-phase machine by auxiliary converter for locomotive auxiliary power supply. Moreover, this paper analyzes the necessity of auxiliary power system reconstruction, and the domestic and foreign various auxiliary converter topologies, then determines the specific auxiliary converter program for specific environments of SS4B electric locomotive, and establish a model in MATLAB/SIMULINK for simulation analysis.A split-phase machine finite element model is established in finite element analysis software to analyze the split-phase machine electromagnetic. The existing of split-phase machine output voltage imbalance is verified, as same as the poor power quality. However, through the coupling model found that no adverse effect on main transformer. This paper also establishes a coupling model of the main transformer and the auxiliary converter, find that after the introduction of auxiliary converters, although improving the quality of the auxiliary power supply system, but while causing the DC magnetic bias of the main transformer. And variations of excitation current and magnetic flux leakage caused by DC magnetic bias have been researched. In order to inhibit the DC bias magnetic, this paper presents an auxiliary converter control optimization strategy, and verified by simulation through that the optimized control strategy does not inject the DC component in transformer. However, this optimization strategy requires sacrificed at the expense of power supply quality, after study found that this optimization approach is more good than harm. |
