用于牵引变电所自用电系统的单相—三相变换器研究

发布时间：2018-06-14 23:47

本文选题：牵引变电所 + 单相-三相变换器　；参考：《西南交通大学》2017年硕士论文

【摘要】：在牵引变电所中,非牵引负荷主要由电力贯通线或牵引网接动力变压器供电。从牵引网取得的交流单相电源,存在电压波动范围大、谐波含量复杂、电流污染等严重的电能质量问题。因此,研究将牵引网取得的电能作为非牵引负荷的电源显得尤为重要,也对铁路电力安全平稳运行具有十分重要的意义。本文以牵引变电所自用电系统为研究背景,首次提出了以单相-三相变换器替代既有的自用电动力变压器,既能对谐波和无功进行补偿,又能向逆变侧传递有功功率,大幅度提高动力电的供电电能质量,同时从理论研究、仿真分析和实验验证三方面对单相-三相变换器主电路结构、控制系统及其调制策略进行了深入研究。首先,建立了单相-三相变换器的数学模型,分别阐述了单相变换器和三相变换器的工作原理,以三相电路的谐波电流检测原理为例引申到单相电路的谐波电流检测原理,着重研究了单相变换器中基于瞬时无功理论的谐波电流检测和基于有功无功解耦的谐波电流检测两种算法。比较了两种算法在主电路参数和控制策略相同的情况下,补偿效果的差异。得到了在网侧电压相对良好的情况下,两种谐波电流检测算法补偿效果基本一致的结论。与基于瞬时无功理论的谐波电流算法相比,基于有功无功解耦的谐波电流检测算法由于没有计算瞬时有功和瞬时无功的过程,因而每个周期内的计算量大大降低,直流侧动态响应时间相应缩短,超调量增大。其次,通过仿真软件平台研究了单相-三相变换器的谐波补偿和功率传递的情况,研究了在牵引网电压升高、降低、突变时单相-三相变换器的网侧、直流侧、逆变侧的系统响应;同时,三相逆变侧可以为负载提供稳定的电压源,使负载正常工作。单相-三相变换器的输出可控,动静态性能良好,在负载变动时可快速响应。最后,搭建了基于FPGA的小功率实验平台,进一步验证了本文所设计的单相-三相变换器不仅可以进行网侧电能质量的补偿,还可以向三相逆变侧传输有功功率,稳态和动态实验响应良好,在较短时间内就可以完成谐波补偿并稳定中间直流电压,系统具有较高的可靠性。
[Abstract]:In the traction substation, the non-traction load is mainly supplied by the power transformer through the power line or the traction network. The AC single-phase power supply obtained from the traction network has serious power quality problems, such as wide voltage fluctuation range, complex harmonic content, current pollution, and so on. Therefore, it is very important to study the electric energy obtained by traction network as a non-traction load power supply, and it is also of great significance to the safe and stable operation of railway power. In this paper, based on the research background of traction substation self-electricity system, a single-phase three-phase converter is proposed to replace the existing self-electric power transformer for the first time. It can not only compensate the harmonic and reactive power, but also transfer the active power to the inverter side. The power quality of power supply is greatly improved. The main circuit structure, control system and modulation strategy of single-phase to three-phase converter are studied from three aspects: theoretical research, simulation analysis and experimental verification. First of all, the mathematical model of single-phase to three-phase converter is established, and the working principle of single-phase converter and three-phase converter are expounded, and the harmonic current detection principle of three-phase circuit is extended to the harmonic current detection principle of single-phase circuit. The harmonic current detection algorithm based on instantaneous reactive power theory and the harmonic current detection algorithm based on active and reactive power decoupling in single-phase converter are studied. The difference of compensation effect between the two algorithms is compared when the main circuit parameters and control strategies are the same. It is concluded that the compensation effect of the two harmonic current detection algorithms is basically the same when the grid voltage is relatively good. Compared with the harmonic current algorithm based on instantaneous reactive power theory, the harmonic current detection algorithm based on active and reactive power decoupling has not calculated the process of instantaneous active power and instantaneous reactive power, so the calculation amount in each cycle is greatly reduced. The dynamic response time of DC side is shortened and the overshoot is increased. Secondly, through the simulation software platform, the harmonic compensation and power transfer of the single-phase to three-phase converter are studied, and the grid-side and DC side of the single-phase three-phase converter are studied when the voltage of traction network rises, decreases and changes. At the same time, the three-phase inverter side can provide a stable voltage source for the load and make the load work normally. The output of single-phase-three-phase converter is controllable and its dynamic and static performance is good. Finally, a low-power experimental platform based on FPGA is built, which further verifies that the single-phase three-phase converter designed in this paper can not only compensate the power quality of the grid side, but also transmit active power to the three-phase inverter side. The steady-state and dynamic experimental results show that the harmonic compensation can be completed in a short time and the intermediate DC voltage can be stabilized. The system has high reliability.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U224

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