PWM整流预测直接功率控制策略研究

发布时间：2018-06-13 22:19

本文选题：PWM整流器 + 模型预测　；参考：《河南科技大学》2017年硕士论文

【摘要】：由不可控器件二极管和半控型器件晶闸管构成早期的整流电路进行整流,这种整流电路,由于结构简单,易于实现,但是存在较高的电流谐波分量并且向电网吸收无功功率,对电网产生了一定的污染。PWM整流器由于输入电流谐波畸变率低;网侧电流正弦化;电能双向传输;功率因数高等优点已逐步替代了早期的整流电路,因此PWM整流器也得到了广大学者的重视,并且对其控制策略进行更深入地研究具有重大的意义。本文首先对三相电压型PWM整流器的拓扑结构和四象限运行原理进行了分析,应用坐标变换理论,在三相静止abc坐标系和两相静止αβ坐标系下建立相应的数学模型。其次介绍了传统的直接功率控制策略,针对该控制策略存在功率开关的开关频率不固定,网侧电流谐波分量高等缺点,提出一种基于模型预测三相电压型PWM整流器直接功率控制策略,该控制策略实现双闭环控制,同时应用SVPWM技术实现固定的开关频率,为了能尽可能的降低系统的成本又提出了一种基于虚拟磁链三相PWM整流器模型预测直接功率控制策略,通过设计虚拟磁链观测器进行磁链观测从而来省去交流侧电压互感器,提高了系统的经济性。第三针对本文提出的这两种控制策略在MATLAB/Simulink中搭建系统仿真模型,通过仿真和对比分析验证这两种控制策略的优越性。最后,在理论分析的基础上,针对这两种PWM整流器控制方法进行了系统的总体方案设计。对系统的主电路、控制电路、检测电路、驱动电路进行硬件设计,并对该系统进行了软件流程设计。
[Abstract]:The early rectifier circuit is composed of an uncontrollable device diode and a half-controlled device thyristor. The rectifier circuit is simple in structure and easy to realize, but it has a high current harmonic component and absorbs reactive power to the power network. The PWM rectifier has some advantages such as low harmonic distortion rate of input current, sinusoidal current on the grid side, two-way transmission of electric energy, high power factor and so on, which have gradually replaced the early rectifier circuit. Therefore, PWM rectifier has been paid more attention by many scholars, and it is of great significance to study its control strategy more deeply. In this paper, the topological structure and four-quadrant operation principle of three-phase voltage-source PWM rectifier are analyzed, and the corresponding mathematical models are established in three-phase static abc coordinate system and two-phase static 伪尾 coordinate system by using coordinate transformation theory. Secondly, this paper introduces the traditional direct power control strategy, aiming at the shortcomings of the switching frequency of the power switch and the high harmonic component of the network side current. A direct power control strategy for three-phase voltage source PWM rectifier based on model prediction is proposed. The control strategy realizes double closed loop control and the fixed switching frequency is realized by using SVPWM technology. In order to reduce the cost of the system as much as possible and propose a direct power control strategy based on the virtual flux chain three-phase PWM rectifier model, a virtual flux observer is designed to observe the flux so as to save the AC side voltage transformer. The economy of the system is improved. Thirdly, the system simulation model is built in MATLAB / Simulink for the two control strategies proposed in this paper. The superiority of the two control strategies is verified by simulation and comparative analysis. Finally, on the basis of theoretical analysis, the overall scheme of the two PWM rectifier control methods is designed. The main circuit, control circuit, detection circuit and drive circuit of the system are designed, and the software flow is designed.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM461

【参考文献】