三相三线制有源电力滤波器关键技术的研究
发布时间：2018-12-31 17:26
【摘要】：现今,有源电力滤波器已经成为一种主流的电能质量调节装置,其中并联型有源电力滤波器是各类有源电力滤波器中发展最为成熟的一种,也是实用化最多的一种有源电力滤波器。本文的研究对象是应用于三相三线电网系统的并联型有源电力滤波器,着重分析和比较了现今主流的实用化技术。本文对几种不同结构的LCL开关纹波滤波器进行了比较分析,并给出了一种基于迭代算法的并联陷波器LCL滤波器设计方法。在确定系统主电路拓扑和相关参数前提下,对比分析了并联陷波器LCL滤波器、选择阻尼LCL滤波器和LRCL滤波器的滤波器特性。利用LCL滤波器的谐振频率公式和特定频率下高频纹波支路的电路等效,设计了一种可以精确确定滤波器谐振频率的迭代算法,避免了直接对高阶滤波器系统的分析,并由此给出了并联陷波器LCL滤波器的设计方法,该方法算法简单,设计误差小。针对电流跟踪控制采用PI控制时滤波器的谐波补偿精度低的缺点,本文设计了一种由PI环节并联准谐振环节构成的三相三线制有源电力滤波器电流跟踪控制策略。在建立系统数学模型的基础上,设计了一种适用于特定次谐波补偿的电流控制策略,在传统PI控制的基础上,增加若干个准谐振环节对谐波指令电流与补偿电流的误差的特定频率成分进行积分,提高电流控制的跟踪精度。为了防止母线稳压外环的影响,电压外环的输出不通过准谐振环节。这种控制策略能够高精度的跟踪特定频率的谐波,而且有较好的母线稳压性能。本文对变流器直流母线不均压的内在原因进行了分析。针对均压控制策略为冗余小矢量法时正负母线电压偏差大的缺点,从矢量选择和作用时间计算两方面对其进行改进,设计了一种改进的冗余小矢量均压控制策略。该控制策略能够有效的减少正负母线电压差的波动范围,改善了均压控制的动态性能,仿真和实验验证了改进的正确性。研究并比较了FFT谐波检测法和ip-iq谐波检测法。当电网频率波动时,频谱泄露和栅栏效应会严重影响FFT谐波检测的精度,对比了采用不同加窗算法时FFT谐波检测的精度,布莱克曼-哈尔斯窗拥有良好的旁瓣特性,能够很好的抑制频谱泄露。对ip-iq谐波检测的低通滤波器和锁相环进行了分析和设计,锁相环和低通滤波器的精度分别影响了ip-iq谐波检测的相位和幅值精度。在电网频率波动时,ip-iq法的幅值检测精度略微高于FFT法,FFT法相位检测精度略微高于ip-iq法。
[Abstract]:Nowadays, active power filter (APF) has become a mainstream power quality regulator, among which shunt APF is one of the most mature active power filters. It is also the most practical active power filter. The research object of this paper is shunt active power filter which is applied to three-phase three-wire power system. In this paper, several LCL switching ripple filters with different structures are compared and analyzed, and a design method of parallel notch filter LCL filter based on iterative algorithm is presented. On the premise of determining the topology and related parameters of the main circuit of the system, the filter characteristics of the parallel notch filter LCL filter and the damping LCL filter and LRCL filter are compared and analyzed. Using the resonant frequency formula of LCL filter and the circuit equivalence of high frequency ripple branch at specific frequency, an iterative algorithm is designed to accurately determine the resonant frequency of filter, which avoids the direct analysis of high order filter system. The design method of parallel notch filter LCL filter is presented. The algorithm is simple and the design error is small. Aiming at the disadvantage of low harmonic compensation accuracy of the filter when current tracking control adopts PI control, this paper designs a three-phase three-wire active power filter current tracking control strategy, which is composed of PI parallel quasi-resonant link and three-phase three-wire active power filter. Based on the mathematical model of the system, a current control strategy suitable for special subharmonic compensation is designed. Based on the traditional PI control, A number of quasi-resonant links are added to integrate the specific frequency components of the error between the harmonic command current and the compensation current to improve the tracking accuracy of the current control. In order to prevent the influence of the bus voltage stabilized outer loop, the output of the voltage outer loop does not pass through the quasi-resonant link. This control strategy can track harmonics at specific frequencies with high accuracy and has good bus voltage stabilization performance. In this paper, the internal causes of the uneven voltage of DC busbar in converter are analyzed. Aiming at the disadvantage of large voltage deviation between positive and negative busbar when the voltage sharing control strategy is redundant small vector method, this paper improves it from two aspects: vector selection and operation time calculation, and designs an improved redundant small vector voltage sharing control strategy. This control strategy can effectively reduce the fluctuation range of positive and negative bus voltage difference and improve the dynamic performance of the voltage sharing control. The simulation and experimental results show that the improved method is correct. FFT harmonic detection method and ip-iq harmonic detection method are studied and compared. When the frequency of power network fluctuates, spectrum leakage and fence effect will seriously affect the accuracy of FFT harmonic detection. Compared with different windowed algorithms, the accuracy of FFT harmonic detection is compared. The Blackman-Hals window has good sidelobe characteristics. It can restrain spectrum leakage very well. The low pass filter and phase locked loop for ip-iq harmonic detection are analyzed and designed. The precision of phase locked loop and low pass filter affect the phase and amplitude accuracy of ip-iq harmonic detection, respectively. The amplitude detection accuracy of ip-iq method is slightly higher than that of FFT method, and that of FFT method is slightly higher than that of ip-iq method.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM761
，
本文编号：2396886
[Abstract]:Nowadays, active power filter (APF) has become a mainstream power quality regulator, among which shunt APF is one of the most mature active power filters. It is also the most practical active power filter. The research object of this paper is shunt active power filter which is applied to three-phase three-wire power system. In this paper, several LCL switching ripple filters with different structures are compared and analyzed, and a design method of parallel notch filter LCL filter based on iterative algorithm is presented. On the premise of determining the topology and related parameters of the main circuit of the system, the filter characteristics of the parallel notch filter LCL filter and the damping LCL filter and LRCL filter are compared and analyzed. Using the resonant frequency formula of LCL filter and the circuit equivalence of high frequency ripple branch at specific frequency, an iterative algorithm is designed to accurately determine the resonant frequency of filter, which avoids the direct analysis of high order filter system. The design method of parallel notch filter LCL filter is presented. The algorithm is simple and the design error is small. Aiming at the disadvantage of low harmonic compensation accuracy of the filter when current tracking control adopts PI control, this paper designs a three-phase three-wire active power filter current tracking control strategy, which is composed of PI parallel quasi-resonant link and three-phase three-wire active power filter. Based on the mathematical model of the system, a current control strategy suitable for special subharmonic compensation is designed. Based on the traditional PI control, A number of quasi-resonant links are added to integrate the specific frequency components of the error between the harmonic command current and the compensation current to improve the tracking accuracy of the current control. In order to prevent the influence of the bus voltage stabilized outer loop, the output of the voltage outer loop does not pass through the quasi-resonant link. This control strategy can track harmonics at specific frequencies with high accuracy and has good bus voltage stabilization performance. In this paper, the internal causes of the uneven voltage of DC busbar in converter are analyzed. Aiming at the disadvantage of large voltage deviation between positive and negative busbar when the voltage sharing control strategy is redundant small vector method, this paper improves it from two aspects: vector selection and operation time calculation, and designs an improved redundant small vector voltage sharing control strategy. This control strategy can effectively reduce the fluctuation range of positive and negative bus voltage difference and improve the dynamic performance of the voltage sharing control. The simulation and experimental results show that the improved method is correct. FFT harmonic detection method and ip-iq harmonic detection method are studied and compared. When the frequency of power network fluctuates, spectrum leakage and fence effect will seriously affect the accuracy of FFT harmonic detection. Compared with different windowed algorithms, the accuracy of FFT harmonic detection is compared. The Blackman-Hals window has good sidelobe characteristics. It can restrain spectrum leakage very well. The low pass filter and phase locked loop for ip-iq harmonic detection are analyzed and designed. The precision of phase locked loop and low pass filter affect the phase and amplitude accuracy of ip-iq harmonic detection, respectively. The amplitude detection accuracy of ip-iq method is slightly higher than that of FFT method, and that of FFT method is slightly higher than that of ip-iq method.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM761
，
本文编号：2396886
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