新型双三电平变换器的控制研究

发布时间：2018-06-08 08:19

本文选题：新型双三电平变换器 + 控制策略的改进　；参考：《中国矿业大学》2017年硕士论文

【摘要】：多电平变换器作为重要的电力电子设备,在能源节约、新能源开发、电力机车牵引等方面发挥着重要的作用。随着我国工业的发展,对多电平变换器的需求也更加多元化,要求其发挥的作用也更加多样。多电平变换器对我国产业的转型、新型产业的发展也将起到促进作用。传统的多电平变换器由于其拓扑结构的限制、控制方法的约束,发挥的作用也受到限制。对传统多电平变换器拓扑的改进、新型拓扑的开发,目前国内外做了很多的研究。新型双三电平变换器比传统多电平变换器有着其特有的优势,本文以此为基础做了大量的研究。首先,介绍了新型双三电平变换器的拓扑结构,详细分析了其工作原理和开关状态,确定了双三电平变换器整流侧的数学模型。介绍了三种常用的调制策略并分析其各自的特点,新型双三电平变换器采用简化的电压空间矢量PWM控制技术作为其调制策略,节省了程序运行的时间。介绍了新型双三电平变换器的悬浮电容预充电控制,有效减小了电容预充电时电流对拓扑器件的冲击。其次,针对新型双三电平变换器初始控制策略在其工作运行时存在的问题进行了改进。改进控制策略I运用整流侧的开关冗余对开关状态进行调整,其有效减小了不可控区的面积,但在实验平台上实现的程序较复杂。改进控制策略II在进行占空比计算时根据整流侧和逆变侧的工作情况进行更合理的分配,在实验平台上实现较容易一些。通过仿真验证了两种改进控制策略较初始控制策略的控制效果更好。再次,针对新型双三电平变换器的改进控制策略在调压调频运行时电网侧电流幅值波动的问题,提出解决措施。一方面通过分析可知,当逆变侧调压调频工作且调制度满足1-mA_rec?mA_inv时,不存在不可控区,通过减小整流侧调制度mA_rec或逆变侧调制度mA_inv都可以减小不可控区。另一方面通过相内电容电压波动相抵消的方法可以较好的解决电网侧电流幅值波动的问题。通过仿真分析验证了这两种控制方法的正确性和有效性。最后,通过搭建实验平台,进行系统软件的设计,把改进的控制策略在实验平台上进行调试运行,获得实验波形。通过对实验结果的分析可知,改进的控制策略在实验平台上运行效果较好。
[Abstract]:As an important power electronic equipment, multilevel converter plays an important role in energy saving, new energy development, electric locomotive traction and so on. With the development of industry in China, the demand for multilevel converters is more diversified, and the role of multilevel converters is more diverse. Multilevel converters will promote the industrial transformation and the development of new industries in China. Traditional multilevel converters are restricted by their topology and control methods. Many researches have been done at home and abroad on the improvement of traditional multilevel converter topology and the development of new topology. Compared with the traditional multilevel converters, the new two-three-level converters have their unique advantages. Based on this, a lot of research has been done in this paper. Firstly, the topology of a new type of bi-three-level converter is introduced, its working principle and switching state are analyzed in detail, and the mathematical model of the rectifier side of the bi-three-level converter is determined. Three common modulation strategies are introduced and their respective characteristics are analyzed. A simplified voltage space vector PWM control technique is used as the modulation strategy for a new type of two-level three-level converter, which saves the running time of the program. In this paper, the levitation capacitor precharge control of a novel two-three-level converter is introduced, which effectively reduces the impact of the current on the topology device during the capacitor precharging. Secondly, the problems existing in the initial control strategy of the new two-three-level converter are improved. The improved control strategy I uses the switching redundancy of the rectifier side to adjust the switching state, which effectively reduces the area of the uncontrollable region, but the program implemented on the experimental platform is more complex. When the duty cycle is calculated, the improved control strategy II is more reasonably distributed according to the working conditions of the rectifier side and the inverter side, and it is easier to implement on the experimental platform. The simulation results show that the two improved control strategies are more effective than the initial control strategies. Thirdly, to solve the problem of the amplitude fluctuation of the current in the power network side of the new dual-three-level converter when the voltage modulation and frequency modulation operation is improved, the solution is put forward. On the one hand, it can be seen that there is no uncontrollable region when the inverter side voltage modulation works and the modulation system meets the 1-mA_rec?mA_inv, and the uncontrollable region can be reduced by reducing the rectifier side modulation mA_rec or the inverter side modulation mA_inv. On the other hand, the fluctuation of current amplitude in the power grid can be solved better by the method of compensating the fluctuation of the voltage fluctuation of the capacitor in the phase. The correctness and effectiveness of the two control methods are verified by simulation analysis. Finally, by setting up the experimental platform and designing the system software, the improved control strategy is debugged and run on the experimental platform, and the experimental waveform is obtained. Through the analysis of the experimental results, it can be seen that the improved control strategy works well on the experimental platform.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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