级联三相桥型有源电力滤波器的研究

发布时间：2018-02-26 11:39

本文关键词： 有源电力滤波器级联三相桥变换器载波相移PWM技术直流侧电容电压控制　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：各种非线性负载的使用给电网注入了大量的谐波和无功,造成电能质量下降,影响电力系统的安全稳定运行,对谐波和无功的治理已经成了刻不容缓的事情。有源电力滤波器(Active Power Filter,APF)可动态抑制谐波和补偿无功,与传统的无源滤波器相比,具有响应快,易控制,且不会与电网阻抗发生谐振等优点,已成为治理谐波和无功污染的重要手段。随着电网容量的不断提高,对APF的要求也越来越高,特别是在一些大功率场合,传统的APF受制于开关器件耐压等级与开关频率的限制,已经不能满足要求,多电平APF的提出能很好地解决这一矛盾。目前应用最广泛的多电平APF是级联H桥APF,但用于三相系统时需要经过三角形或者星形连接。本文研究的级联三相桥型APF可以直接应用于三相高压大功率场合,且易于模块化设计,在大功率电能质量研究领域中具有很好的应用前景。载波相移PWM(Carrier Phase-Shifted PWM,CPS-PWM)技术结合了正弦脉宽调制技术与多重化技术的优点,具有谐波特性良好和开关负荷均衡等优点,已成为多电平变换器最优的调制策略。本文将CPS-PWM技术应用在级联三相桥型APF中,使之具有了级联三相桥变换器和CPS-PWM技术的优点,从而可以获得较高的输出电压等级和良好的谐波特性。级联三相桥APF直流侧有多个电容,直流侧电容电压的稳定和均压在很大程度上决定了整个系统补偿性能的优劣。通过对级联三相桥变换器的电量关系的分析,发现其每个子模块传输的瞬时功率是波动的,这将给APF直流侧电容电压保持恒定均压带来不便。所以本文根据级联三相桥型APF的特点,并结合传统三相桥APF和级联H桥APF的控制方式,经过改进得到了两种直流侧电容电压的控制方式,分别称为方式一和方式二。最后,采用基于瞬时无功功率理论的ip-iq检测法,在matlab/simulink中搭建二级级联三相桥型APF仿真模型,对两种控制方式下系统的静态和动态性能进行仿真分析。仿真结果表明,在这两种控制方式下,直流侧电容电压实现了恒定均压,且整个系统有良好的静态和动态补偿效果,其中在方式一控制下补偿后的电流总谐波畸变率(Total Harmonic Distortion,THD)比采用方式二时小,但方式一的控制方式比方式二复杂。
[Abstract]:The use of various nonlinear loads has injected a large number of harmonics and reactive power into the power network, resulting in a decline in power quality, which affects the safe and stable operation of the power system. The treatment of harmonic and reactive power has become an urgent task. Active Power filter can dynamically suppress harmonics and compensate reactive power. Compared with traditional passive filter, it has fast response and easy control. It has become an important means to control harmonic and reactive power pollution. With the continuous improvement of power network capacity, the demand for APF is becoming higher and higher, especially in some high-power occasions. The traditional APF is limited by the voltage level and the switching frequency of the switch device, so it can not meet the requirements. The multilevel APF can solve this contradiction well. The most widely used multilevel APF is cascaded H-bridge APF, but it needs triangle or star connection when it is used in three-phase system. The cascaded three-phase bridge APF is studied in this paper. It can be directly used in three-phase high-voltage and high-power occasions. It is easy to modularize design and has a good application prospect in the field of high-power power quality research. The carrier phase-shifted PWM(Carrier Phase-Shifted PWM / CPS-PWMM technology combines the advantages of sinusoidal pulse width modulation technology and multiplex technology. With the advantages of good harmonic characteristics and switching load equalization, it has become the optimal modulation strategy for multilevel converters. In this paper, CPS-PWM technology is applied to cascaded three-phase bridge APF, which has the advantages of cascaded three-phase bridge converters and CPS-PWM technologies. Therefore, higher output voltage level and better harmonic characteristics can be obtained. There are several capacitors on the DC side of the cascaded three-phase bridge APF. The stability and voltage equalization of DC capacitor voltage determine the compensation performance of the whole system to a great extent. Through the analysis of the power relationship of the cascaded three-phase bridge converter, it is found that the instantaneous power transmitted by each sub-module is fluctuating. Therefore, according to the characteristics of cascaded three-phase bridge APF and the traditional three-phase bridge APF and cascaded H-bridge APF control mode, Two kinds of DC side capacitive voltage control methods are obtained, which are called mode one and mode two. Finally, a two-stage cascaded three-phase bridge APF simulation model is built in matlab/simulink by using ip-iq detection method based on instantaneous reactive power theory. The static and dynamic performances of the system are simulated and analyzed under the two control modes. The simulation results show that the DC side capacitance voltage achieves constant voltage sharing under these two control modes, and the whole system has a good static and dynamic compensation effect. The total Harmonic distortion rate (THD) compensated by mode one is smaller than that of mode 2, but the control mode of mode 1 is more complex than mode 2.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM761;TN713.8

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