【作者】 王文；

【导师】 罗安；

【作者基本信息】 湖南大学 ， 电气工程， 2013， 博士

【摘要】 四开关型有源电力滤波器(Four-switch-type Active Power Filter, F-APF)可以作为传统的六开关型有源电力滤波器在故障重构后的容错电路拓扑,具有在六开关逆变器故障时迅速恢复系统部分性能的潜力,同时由于减少了一对开关器件,F-APF具有装置成本低、损耗少、体积小、驱动电路简单及可靠性高等优势,因此具有重要的研究价值。本论文得到了国家“863”计划项目“大型工业企业电气节能新技术新装备及其工程应用”和国家自然科学基金重点项目“微网多逆变器并联及电能质量控制方法研究”的资助,围绕F-APF的控制方法与工程应用展开,分别对三相四开关有源电力滤波器(Three-phase Four-switch Shunt Active Power Filter, TFSSAPF)的工作原理与空间矢量电压调制算法、空间矢量离散电流控制方法以及直流侧电容电压控制方法进行了研究,在此基础上,结合微源逆变器的结构特点和某110kV变电站的电能质量情况,分别研究了TFSSAPF在低压微网和高压配电网中的相关应用问题,主要研究内容和创新如下：(1)分析了TFSSAPF的工作原理,提出了一种空间矢量调制算法(SVPWM),大幅度优化了触发脉冲生成方法的总体计算量和计算精度。通过详细分析TFSSAPF的拓扑结构,本文揭示了TFSSAPF输出三相平衡正序(负序)电压的条件,为TFSSAPF对谐波、无功及负序电流的补偿奠定了基础。提出了一种改进的坐标变换式,使基本输出电压空间矢量位于αβ坐标系的坐标轴上,只需进行简单的符号判断和四则运算即可得到参考电压矢量的扇区和基本电压矢量的作用时间,在总体计算量和计算精度上得到了大幅度的优化。通过控制幅值相同、方向相反的一对基本电压矢量在单位开关周期内的作用相同时间的方法合成零矢量,提出了一种五段式SVPWM算法,通过搭建仿真模型和样机实验平台验证了TFSSAPF原理分析的正确性以及所提SVPWM算法的有效性。(2)揭示了空间矢量电流控制方法中等效误差电压矢量的约束条件,提出了一种TFSSAPF双滞环离散电流控制方法,提高了指令电流的跟踪速度,降低了开关管的工作频率。本文分析了TFSSAPF采用空间矢量方法进行电流控制时,等效误差电压矢量的约束条件,既保证误差电流幅值减小,又不超出TFSSAPF的输出能力；指出了等效误差电压矢量的最优方向,以使单位幅值的等效误差电压矢量能产生最大的误差电流矢量幅值衰减；采用离散方法描述了实现指令电流精确实时跟踪的输出电压表达式,并提出了一种TFSSAPF双滞环离散电流控制方法,在误差电流较大时进行矢量合成,在误差电流较小时选择最优矢量输出,既满足电流畸变率要求,又降低开关管的工作频率。仿真和实验说明了所提方法在参考电流跟踪速度提高和功率器件开关频率降低上的优越性。(3)建立了TFSSAPF的基本数学模型,对TFSSAPF的直流侧电容电压控制目标进行了描述,提出了一种基于相电流调制的TFSSAPF直流侧电容电压控制方法,保证了直流侧电容电压的稳定。本文分析了TFSSAPF的能量交换原理,采用控制TFSSAPF输出电流有功分量的方法来实现直流侧电容总电压均值的恒定；建立了直流侧电容平均电压差值和TFSSAPF的C相输出电压的关系,提出在C相指令电流中叠加均压控制量的方法来实现直流侧两电容均压。提出以相电流作为指令电流的SPWM电流调制算法,弥补了传统的线电流调制方法应用于TFSSAPF时的弊端。综合相电流SPWM电流调制算法、直流侧电容总电压均值稳定方法和直流侧两电容电压平衡方法,提出一种TFSSAPF直流侧电容电压控制方法,并对关键参数设计方法进行了分析。通过搭建样机实验平台验证了所提方法的有效性。(4)分析了在虚拟阻抗存在时,负载谐波电流对微网逆变器性能的影响,提出一种TFSSAPF的复合控制方法,用于控制TFSSAPF以调节微网母线电压角频率并抑制负载谐波,消除负载谐波对微源逆变器的影响,并充分利用其无功容量。本文通过建立微网逆变器系统的等效模型,对负载谐波引起的逆变器功率检测偏差进行了详细分析,引入虚拟谐波功率的概念对误差进行量化,采用小信号分析方法说明了负载谐波电流对微网逆变器性能的影响并进行了仿真验证。为了减小负载谐波对微网逆变器的影响,并利用TFSSAPF的无功容量,提出了一种TFSSAPF的复合控制算法,在TFSSAPF参考电流中加入了用于调节母线电压角频率的无功分量来对母线电压频率波动进行补偿,仿真分析说明,该算法能降低母线角频率误差值,并补偿负载谐波电流,提高了微网逆变器的稳定性。(5)分析了某110kV变电站的电能质量情况,针对其电能质量问题提出种FSI-HAPF结构,并对软硬件系统进行了设计,实现了在35kV侧进行大容量无功补偿和动态谐波治理的目的。本文分析了某110kV变电站的基本电能质量情况,参照电能质量国家标准说明35kV母线Ⅰ段存在的谐波污染及无功不足问题。提出了一套高压配网混合补偿装置FSI-HAPF,由TFSSAPF和谐振注入支路组组成,与传统注入式混合有源滤波器相比,造价更低,可靠性更高。阐述了FSI-HAPF的结构及滤波原理,从无源和有源部分说明了FSI-HAPF的主电路参数设计方法,介绍了FSI-HAPF控制系统软硬件部分设计思路与实现方法。工程应用效果显示,该装置能够满足工业现场的需求,使35kV母线Ⅰ段的主要电能质量指标降低至国标限值以下,以较低的成本达到了高压系统谐波动态治理和大容量无功补偿的目的。更多还原

【Abstract】 Four-switch-type Active Power Filters (F-APF) could be used as fault tolerant circuit topology of traditional Six-switch-type Active Power Filters (S-APF). It has the potential to restore part of the system performance rapidly when the S-APF goes wrong. In addition, as two switching devices have been reduced, F-APF has the advantages of lower cost, lower loss, smaller size, simpler driving circuit and higher reliability. Therefore, F-APF has significant research value. Based on the financial support of The National High Technology Research and Development of China (863Program) and The National Natural Science Foundation of China, this paper emphasizes on the control method and engineering application of F-APF. The working principle, space vector pulse width modulation (SVPWM) algorithm, space vector discrete current control method and dc side capacitor voltage control method of Three-phase Four-switch Shunt Active Power Filter (TFSSAPF) are firstly discussed, then according to the characteristics of micro-grid inverters and the power quality of a110kV substation, the problems related to the application of TFSSAPFs in low voltage micro-grid and high voltage distribution network are studied in detail. The emphasis and achievement of the paper mainly manifests in the following aspects:(1) The working principle of TFSSAPF is analyzed and a SVPWM algorithm is proposed, which is able to greatly optimize the total computational amount and accuracy of the trigger pulse production method.After analyzing the topology of TFSSAPF in detail, the conditions to control TFSSAPF to output three-phase balanced positive sequence(or negative sequence) voltage are revealed, which lays the foundation to eliminate harmonic currents, compensate reactive power and suppress negative sequence currents. An improved coordinate transformation is proposed which can make the basic output voltage space vector locate right on the axes of the αβ coordinate system. The sectors of reference voltage vectors and action time of fundamental voltage vectors can be acquired by simple sign judgment and arithmetic operation, thus the calculation amount and accuracy are optimized significantly. The pair of basic voltage vectors which are of the same amplitude and opposite direction are controlled to act the same time in a switching cycle to obtain zero vectors. Furthermore, a five-segment SVPWM algorithm is proposed and the realization process is also presented. Simulations and experimental results have validated the correctness of theory analysis and the effectiveness of the proposed algorithm.(2)The constraint condition of the equivalent voltage error vector of the space vector current control method is explained and a dual-hysteresis space-vector discrete current control method for TFSSAPF is proposed, which has the advantage of increasing the tracing speed of instruction currents and decreasing the operation frequency of the power switches.The constraint condition of the equivalent voltage error vector is analyzed when the space vector current control method is used for TFSSAPF. This condition ensures that the magnitude of the current error is reduced and the equivalent voltage error vector is within the output capacity of TFSSAPF. The optimal direction of the equivalent voltage error vector is pointed out. In this direction, the equivalent error voltage vector with unit amplitude can produce the greatest attenuation of the current error. Then, the discretization method is used to describe the output voltage expression to realize real-time tracking of the instruction currents. A dual-hysteresis space-vector discrete current control method is proposed, which uses the vector synthesis method when the current error is large and the optimal vector selection method when the current error is small, thus to reduce the switching frequency and meet the requirements of the output current total harmonic distortion. The performance of the proposed method, the optimal voltage vector hysteresis control method and the precise output of output voltage vector method is compared and analyzed in simulation and experiment. The simulation and experimental results have verified the superiority of the proposed method on improving the reference current tracking speed and reducing the switching frequency.(3)The basic mathematical model of TFSSAPF is constructed. The control objectives of dc capacitor-voltage are described, and a dc capacitor-voltage balance control method for TFSSAPF is presented, which ensures the stability of dc-side capacitor voltages.In order to balance the energy storage of dc capacitors and equalize their voltages, energy exchange principle of TFSSAPF is analyzed and a method of controlling the active component of output current is used. The relevance between the output voltage of phase C and the differential value of dc capacitor average voltages is established, and a method to balance the dc capacitor voltages by adding voltage balance component to the reference current of phase C is proposed. A SPWM current modulation algorithm which treats the phase currents as command currents is proposed, which has diminished many drawbacks of the traditional line current modulation method. Combining the SPWM current modulation algorithm based on phase current, the mean value stable method of total voltage of DC capacitor and the balance method of DC side two-capacitor voltage, a method of the DC side capacitor voltage control of TFSSAPF is proposed and the design method of the key parameter are analyzed. The experimental results have verified the effectiveness of the proposed method.(4)The influence of load harmonic currents to inverters in micro grids under the existence of virtual impedance is analyzed. A coordination control method for the TFSSAPF is proposed to regulate the angle frequency of the bus voltage and suppress the load harmonics, which not only eliminates the influence of harmonics, but also sufficiently uses the reactive power capacity of the TFSSAPF.The equivalent model of the micro grid inverter system is established and the deviation of the detected power and the actual power brought by load harmonics is analyzed. By introducing the virtual harmonic power, the deviation is quantified. The influence of load harmonics to the performance of DG inverters is described using the small signal method. In order to reduce the influence mentioned above and increase the capacity utilization ratio of TFSSAPF, a coordination control method is proposed. A reactive current component is added into the reference current to regulate the angle frequency of the bus voltage. The simulation results show that the proposed method could decrease the angle frequency of the bus voltage and suppress the load harmonics, thus the stability of DG inverters is increased.(5) The power quality problems of an110kV substation are analyzed and a power quality compensator FSI-HAPF is presented. The hardware and software of FSI-HAPF is designed in detail, which realizes large capacity reactive power compensation and dynamic harmonic suppression on35kV bus.According to the GB standard of power quality, the power quality problems of110kV HURUN Substation of Guangxi Power Grid is analyzed, which illustrate serious harmonic pollution and inadequate capacity of reactive power existed in segment I of35kV bus. A high-voltage hybrid compensation system FSI-HAPF based on TFSSAPF is proposed, which consists of TFSSAPF and resonance injection branch group. FSI-HAPF has lower cost and higher reliability than the traditional IHAPF. The structure and filtering principle of the FSI-HAPF is analyzed and the parameter design method of both the passive and active part of FSI-HAPF is provided as well as the design and realization method for the hardware and software of FSI-HAPF. The application results show that FSI-HAPF is able to meet the needs of the industrial requirement. After the application of FSI-HAPF, the main indexs of power quality at segment I of35kV bus is restrained within the national standard (GB) limited values, which indicates that FSI-HAPF has achieved harmonic dynamic management in high-voltage system and large capacity reactive power compensation with low cost.更多还原