【作者】 盘宏斌；

【导师】 罗安；

【作者基本信息】 湖南大学 ， 电气工程， 2009， 博士

【摘要】 无功补偿与谐波抑制是目前电网面临的主要问题,本文在分析混合型有源电力滤波器HAPF无功功率补偿和谐波电流抑制的基础上,提出了将静止无功补偿器SVC与HAPF合二为一的无功与谐波综合补偿的电能质量调节装置,命名为并联型电能质量综合补偿器(SPQCC)。该装置具有SVC和HAPF的优点并摈弃了各自的缺点,在配电网中能有效的解决电压波动与闪变、三相不平衡补偿、谐波电流抑制等电能质量问题。论文对改善配电网电能质量时并联型电能质量综合补偿器SPQCC的拓扑结构及其模型、电压控制策略、不平衡补偿控制、谐波及无功电流检测、系统稳定性及电流跟踪控制等理论和关键技术进行了系统深入地研究。本文首先分析了HAPF的结构,提出了两种类型的并联型电能质量综合补偿器SPQCC的拓扑结构,简述了其工作原理,构建和分析了它们的统一模型。以晶闸管控制电抗器TCR和谐振阻抗型混合有源滤波器RITHAF组成的SPQCC为例,详细分析了其模型并给出了复合控制策略,其中RITHAF的无源滤波器组分成两个部分,一部分为固定连接的二阶高通滤波器和一个2次单调谐滤波器,另一部分是可投切的3次、5次单调谐滤波器构成的投切电容器组TSC。SPQCC不但可以实现无功功率容性与感性范围的连续调节和谐波治理,而且克服了有源滤波器只能发出固定无功和TCR工作时引起电网电流畸变的缺点,具有较大容量的无功功率补偿和谐波电流抑制的优点,且所需APF容量也较小。针对其模型进行的仿真表明SPQCC能对电网电压的波动和电网谐波电流进行补偿,也可以对负载电流中的无功分量和谐波分量进行补偿,在配电网中具有较大的应用空间。其次,针对传统PI控制器的结构简单易于实现但难以适应负荷变化的情况,以及静止无功补偿系统不易建立精确数学模型的难点,在系统电压稳定控制时,提出了优化递推积分PI控制算法,将递推积分PI算法应用于静止无功补偿器中,并对PI控制器的比例、积分参数进行单纯形加速算法(SPX)优化,提出了以ITAE准则作为寻优目标函数的改进的单纯形加速算法对PI控制器的参数Kp、Ki进行实时调整、寻优,使得其比例、积分参数能够实时调整,这样便可以适应负荷的变化等情况,使SVC的响应过程达到最优,能快速、无超调的跟踪系统的电压设定值,从而保证SPQCC的总体性能。对于不平衡负荷平衡化补偿技术中补偿电纳计算误差受电网电压、电流畸变影响较大的特点,提出了基于虚拟对称三相系统的同步参考旋转坐标变换的补偿电纳计算方法,利用电网电压中的一相电压构造虚拟的对称三相系统,用虚拟对称三相系统的合成电压矢量作为旋转坐标系的d轴,便能实现旋转坐标系的d轴近似等效实际的电网电压基波正序分量的合成矢量,由此可以准确计算所需的补偿电纳,该方法计算简单,基于该法的静止无功补偿器不需要硬件锁相环,能够快速、准确的补偿负荷的无功功率。考虑到SPQCC对谐波指令电流要求较高且不能包含有基波成分的原因,在分析其他的谐波及无功电流检测方法的基础上,本文还提出了一种基于自适应噪声对消技术的改进的自适应谐波检测方法,并利用动力系统的均值理论证明了该方法的稳定性,此法克服了传统自适应谐波检测方法的局限性,不仅能够检测电流谐波,而且能够有效地提取电流的畸变量,通过学习率因子的选择,提高了该方法的瞬态响应速度,具有较好的跟踪性能,可用于时变谐波的跟踪检测。仿真结果表明该方法比以往的自适应谐波检测法能更迅速的进行谐波的同步检测和基波的同步提取,满足电力系统对谐波电流和谐波电压检测的要求。文章最后,详细分析了SPQCC逆变器输出电流与指令电流之间存在相位滞后的原因,推导出了广义阻抗,提出了广义滞后的概念和分频预估补偿的思路,并对系统的稳定性进行了分析,给出了其稳定的充要条件。为消除广义滞后对SPQCC带来的不利影响,利用逆变器输出电流与负载及其TCR谐波电流极性相反等同于相位滞后π的原理,构造了一种新型π目标Smith预估器进行滞后补偿。结合广义积分器良好的分频与选频性能,提出了基于广义滞后分频预估补偿的电流广义积分控制方法,进行了PSIM仿真验证,并对所采取的方法的稳态无差特性进行了分析。在上述相关理论和技术的指导下实验室成功研制出了+120kvar～-100kvar的SPQCC实验装置,并在实验样机上进行了大量的实验,实验结果与仿真结果相吻合,验证了上述理论和技术是正确而有效的。更多还原

【Abstract】 Reactive power compensation and harmonic currents elimination are the two important problems to the power distribution system, based on analysis of the Hybrid Active Power Filter (HAPF) for reactive power compensation and harmonic currents suppression, a comprehensive power quality controller for power distribution system combined with Static Var Compensator (SVC) and HAPF is proposed in this paper, named Shunt Power Quality Combined Compensator (SPQCC). The system mentioned has merits of SVC and HAPF, which overcomes the shortcomings of the SVC or APF operation respectively, it not only can improve the voltage fluctuation and flicker, but also can eliminate the negative currents arising from unbalanced load and the harmonic currents generated by nonlinear load and SVC, so can improve the power quality of the power system. The topology structure and model of SPQCC, the scheme of voltage control, the technology of unbalance compensation, the detection of harmonics and reactive current, the stability of the system mentioned in the paper and the technology of current tracing control are described in detail.Firstly, two types of topology structure of SPQCC are proposed based on analysis of the structure of HAPF, their operation principle are introduced, and the general model of the SPQCC are constructed and analyzed in this paper. Then take an example of SPQCC, which composed of Thyristor Controlled Reactors (TCR) and Resonant Impedance Type Hybrid Active Filter (RITHAF), also the model of the system is analyzed in detail and the complex control scheme is proposed. In which the passive filters of the RITHAF is divided to two parts, one is the fixed capacitors composed of 2 order harmonics filter and the high order filter, the other is composed of 3, 5 order filter series thyristor respectively. The reactive power of SPQCC can be controlled from inductive to capacitive smoothly, but also the shortcomings of the supply of the fixed capacitive reactive power of the HAPF and the harmonic currents coming from the TCR are avoided, and the VA of the APF is reduced greatly. Simulation results show that the SPQCC not only compensate the voltage fluctuation and the harmonic currents of the power system, but also can compensate the reactive components and harmonics of the load, and has a wide use in the power distribution system.Secondly, Considering of easy realization but dependence on the accurate mathematical model and difficult to fit to the variation of the load in traditional PI controller used in the SVC, the optimal recursive integral method was mentioned when maintain the voltage stability of the power system, and the recursive integral PI method was used in SVC. The recursive integral PI control method based on improved simplex method (SPX) optimization, the algorithm using ITAE of optimized object function is presented to adjust and optimize the Kp、Ki, parameters of PI controller real-time, which makes transient response procedure of SVC optimum, so it is able to track voltage set values of SVC fast and ensure the performance of the SPQCC. According to unbalanced load compensation, in order to overcome the shortcomings of the compensation susceptance calculation affected by the distortion of the voltage and current of the power system, a new type of compensation susceptance calculation of SVC based on virtual symmetrical three phase synchronous reference frame transform is presented. A single-phase voltage is derived and used to form the virtual symmetrical three-phase system, so the compensation susceptance is calculated accurately. The method of susceptance calculation presented needs simple calculation, the SVC based on the method proposed without Phase Locked Loop (PLL) of hardware and can compensate reactive power accurately.In consideration of the accuracy of the harmonic currents detection and no fundamental component included, an improved adaptive harmonic detection method based on adaptive noise cancelling technology was presented in the paper based on the analysis of the other harmonic currents detection method, its’stability is proved by averaging theorem of dynamical system theory. The proposed method conquers the limitation of the average adaptive harmonic detection methods and is able to detect harmonic as well as extract distortion of currents. The transient speed of the novel adaptive is improved through chose of learning rate. Due to its excellent tracking performance, the improved adaptive one is good at time-varying harmonic’s detection. The simulation results show that the proposed approach is faster than the previous average one for synchronous detection of harmonic and extraction of fundamental component, and satisfy the power system’s needs for harmonic current or harmonic voltage detection.At last, according to the phase delay of output current of the SPQCC, the reason causing the phase delay is analyzed in detail, the phase delay mentioned above is called as generalized delay here, which is variable with different frequency. At the same time, the equation of the generalized impedance and the stability of necessary and sufficient condition of the system proposed are given. In order to eliminate the effects of generalized delay, a novel -aimed Smith predictor is established based on the fact that there is a delay between output current and load and thyristor controlled reactor (TCR) harmonic current, which are negative in polarity. Applying generalized integrators with excellent performances of frequency division, a generalized integral control based on predictive compensation at different frequency for generalized delay is proposed. The feasibility and effectiveness of this control method is verified by PSIM simulation, also no error performance of stability is analyzed in the paper.Under the guidance of the above theories and technologies, a +120kvar—100kvar SPQCC prototype is developed in the lab. A large number of experiments are implemented on the experimental prototype. The experimental results match with the simulation results. The correction and effective of the theories and technologies are verified by the experimental results.更多还原