PI与重复控制的三相四线制并联型有源电力滤波器的研究

发布时间：2018-11-02 09:26

【摘要】：随着电力电子技术的快速发展，越来越多的电力电子设备应用到电力系统中，给电网引入了大量的谐波，对电力系统的安全稳定运行构成威胁。为此，有源电力滤波器（APF:Active Power Filter）作为一种动态抑制谐波和补偿无功功率的新型电力电子装置得到发展和应用。有源电力滤波器的结构根据补偿要求的不同存在一定的差异。本论文主要研究三相四线制并联型有源电力滤波器，文中所做的研究工作有以下几点。第一，对主电路进行了数学建模，推导出系统在静止a-b-c坐标系下的数学模型，从数学模型中可看出系统是一个高阶强耦合系统，控制器设计比较复杂，为了简化控制器的设计，引入d-q-0坐标变换，得到系统在d-q-0旋转坐标系下的数学模型。第二，在三相四线制系统中，针对谐波电流检测是否需要先剔除零序电流然后按三相三线制系统的计算方法计算的探讨，本文对比分析了两种计算方法，并从理论和仿真实验验证了两者的归一性。针对常规锁相法抗干扰能力差的特点，本文分析了三相数字锁相环（DPLL, Digital Phase Lock Loop）的工作原理，并给出了基于零极点配置的PI控制器设计方法。第三，针对单PI控制在APF应用中补偿精度不理想的问题，在电流内环控制中引入基于内模原理的重复控制器（Repetitive Controllers，RCs），给出了RCs的详细设计步骤。针对三维空间矢量（3D-SVPWM）计算量大，扇区判断复杂，文中从理论上推导出3D-SVPWM可以不计算扇区，并得出在a-b-c坐标系下简化的占空比计算公式。第四，介绍了系统的硬件电路和软件设计。硬件电路包括主电路参数的选取以及控制电路的设计。软件设计主要介绍了主程序的工作流程图以及各系统子程序的流程图。最后搭建了SIMULINK系统仿真模型以及100A的实验样机，对比分析了系统在平衡负载以及不平衡负载时的补偿效果、电源电压畸变和电源电压没有畸变时的补偿效果以及负载突变时的补偿效果。实验结果表明，本文所采用的三相四线制系统的谐波电流检测方法是正确的，所采用的三相电源电压数字锁相方法能取得理想的锁相效果，，简化的3D-SVPWM控制策略是有效的，PI+重复控制器能使系统在各种条件下均能取得理想的补偿效果。
[Abstract]:With the rapid development of power electronics technology, more and more power electronic devices are applied to power system, which introduces a large number of harmonics to the power network, which poses a threat to the safe and stable operation of power system. Therefore, active power filter (APF:Active Power Filter) has been developed and applied as a new power electronic device for dynamic harmonic suppression and reactive power compensation. The structure of active power filter is different according to different compensation requirements. This paper mainly studies three-phase four-wire shunt active power filter. First, the mathematical model of the main circuit is established, and the mathematical model of the system in the static a-b-c coordinate system is deduced. From the mathematical model, it can be seen that the system is a high-order strong coupling system, and the controller design is quite complex. In order to simplify the design of the controller, the d-q-0 coordinate transformation is introduced, and the mathematical model of the system in the d-q-0 rotation coordinate system is obtained. Second, in the three-phase four-wire system, this paper compares and analyzes two calculation methods, aiming at whether the harmonic current detection needs to eliminate the zero-sequence current first and then calculate according to the three-phase three-wire system. The normalization of the two is verified by theoretical and simulation experiments. In view of the poor anti-jamming ability of the conventional phase-locked method, the working principle of three-phase digital phase-locked loop (DPLL, Digital Phase Lock Loop) is analyzed, and the design method of PI controller based on zero-pole configuration is presented. Thirdly, aiming at the problem that the compensation precision of single PI control is not ideal in APF application, a repetitive controller (Repetitive Controllers,RCs) based on internal model principle is introduced into the current inner loop control, and the detailed design steps of RCs are given. In view of the complexity of the calculation of three-dimensional space vector (3D-SVPWM) and the complexity of sector judgment, this paper deduces theoretically that 3D-SVPWM can not calculate sector, and obtains the simplified formula of duty cycle in a-b-c coordinate system. Fourthly, the hardware circuit and software design of the system are introduced. The hardware circuit includes the selection of main circuit parameters and the design of control circuit. The software design mainly introduces the working flow chart of the main program and the flow chart of each system subroutine. Finally, the simulation model of SIMULINK system and the experimental prototype of 100A are built, and the compensation effect of the system in balancing load and unbalanced load is compared and analyzed. The compensation effect of power voltage distortion and no distortion of power supply voltage and the compensation effect of load mutation. The experimental results show that the harmonic current detection method used in the three-phase four-wire system is correct, the digital phase-locked method of three-phase power supply voltage can obtain ideal phase-locking effect, and the simplified 3D-SVPWM control strategy is effective. PI repetitive controller can make the system achieve ideal compensation effect under various conditions.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM761;TN713.8

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