基于改进型直接功率控制的三电平PWM整流器的研究

发布时间：2018-10-13 16:57

【摘要】：与传统二极管整流相比,二极管箝位式三电平PWM整流器具有网侧电流谐波小、功率因数可调、能量双向流动及直流电压可调等优点,这些特点使得二极管箝位式三电平PWM整流器在高压输配电、高压大功率电机调速等高压大功率领域有着很好的应用前景。本文以中点箝位式三相三电平SVPWM整流装置作为研究对象。首先,通过对PWM整流器模型电路的研究,分析PWM整流器的运行状态和控制原理。同时,针对中点箝位式三相三电平整流器的拓扑结构,详细分析了其主电路的工作原理。以此为基础,建立了三相三电平整流装置在三相静止abc坐标系下、两相静止αβ坐标系下、两相旋转dq坐标系下的数学模型。之后,又推导了二极管箝位式三电平PWM整流器基于瞬时功率理论的数学模型,为三相三电平整流器控制系统的设计及其优化建立奠定了理论基础。其次,在已经建立的三电平PWM整流器基于瞬时功率控制的数学模型的基础上,对传统基于滞环比较的直接功率控制系统结构进行了详细的研究。然后,针对其不足,运用新的功率控制模型分析方法改进了滞环开关表的设计,从而改善了控制效果。不过,由于采用滞环比较器会使得整流器开关频率不固定,为克服此缺点,本文又提出了一种基于空间矢量的预测直接功率控制策略。该控制策略将功率预测控制理论与空间矢量调制技术结合代替原来的滞环比较器与开关表,实现了频率固定。然后,在PLECS仿真软件的仿真环境下搭建了三相三电平PWM整流器控制系统,并分别对三种控制方法进行了仿真验证,对仿真结果进行了深入的对比分析。最后,在以上理论分析的基础上,建立了DSP+CPLD的控制平台,通过实验验证了基于预测直接功率控制策略的正确性,并通过对调试过程中遇到的问题进行分析解决,进一步提高系统的各项性能指标。
[Abstract]:Compared with the traditional diode rectifier, the diode clamped three-level PWM rectifier has the advantages of low current harmonics, adjustable power factor, bidirectional energy flow and adjustable DC voltage. These characteristics make diode clamped three-level PWM rectifier have a good application prospect in high-voltage power transmission and distribution, high-voltage high-power motor speed regulation and other high-voltage high-power fields. In this paper, the neutral point clamped three-phase three-level SVPWM rectifier is taken as the research object. Firstly, the operation state and control principle of PWM rectifier are analyzed by studying the model circuit of PWM rectifier. At the same time, the principle of the main circuit is analyzed in detail according to the topology of the neutral-point clamped three-phase three-level rectifier. Based on this, the mathematical model of three-phase three-level rectifier in three-phase static abc coordinate system, two-phase static 伪尾 coordinate system and two-phase rotating dq coordinate system is established. Then, the mathematical model of diode clamped three-level PWM rectifier based on instantaneous power theory is derived, which lays a theoretical foundation for the design and optimization of three-phase three-level rectifier control system. Secondly, based on the established mathematical model of three-level PWM rectifier based on instantaneous power control, the structure of traditional direct power control system based on hysteresis comparison is studied in detail. Then, a new power control model analysis method is used to improve the design of hysteresis switch table, which improves the control effect. However, the switching frequency of rectifier is not fixed by hysteresis comparator. In order to overcome this shortcoming, a predictive direct power control strategy based on space vector is proposed in this paper. This control strategy combines power predictive control theory with space vector modulation technology to replace the original hysteresis comparator and switch table to achieve frequency fixed. Then, the three-phase three-level PWM rectifier control system is built under the simulation environment of PLECS simulation software, and the three control methods are verified by simulation, and the simulation results are compared and analyzed deeply. Finally, on the basis of the above theoretical analysis, the control platform of DSP CPLD is established, and the correctness of the direct power control strategy based on prediction is verified by experiments, and the problems encountered in the debugging process are analyzed and solved. Further improve the system performance indicators.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM461

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