【作者】 王伟；

【导师】 周林；

【作者基本信息】 重庆大学 ， 电气工程， 2007， 硕士

【摘要】 非线性负载和各种换流设备的应用,造成的电力系统谐波“污染”是十分严重的,补偿电力系统谐波,改善供电质量成为迫切需要解决的问题。有源电力滤波器(APF)作为一种理想的抑制谐波和改善功率因数的装置,能够对频率和幅值均发生变化的谐波和无功进行补偿,弥补了传统无源电力滤波器的不足,因而得到了迅速的发展,在国外己开始应用于实际生产中。目前,我国对有源电力滤波器的研究和开发尚处于实验阶段,暂时没有大容量的成熟产品投入使用,因此对有源电力滤波器的研究具有十分重要的意义。目前,APF的主电路大多采用两电平变换器,以满足低压场合需要。但是,在高压场合中,电路设计要考虑到半导体功率器件的承压能力。多电平变换器能产生多阶梯、低失真电压波形,具有开关器件承压降低、开关损耗小、效率高、低电磁干扰(EMI)等显著的优势,成为科学技术人员研究的热点。本文将单周控制应用于三电平两桥臂三相三线制APF中,在分析其开关周期平均模型的基础上,建立其数学模型,推导出控制的关键方程,建立了单周控制三电平两桥臂三相三线制APF的电路模型。仿真和分析结果表明,基于单周控制的三电平两桥臂APF控制电路更为简单,容易实现,主电路开关频率恒定,补偿性能接近于单周控制三电平三桥臂三相三线制APF。本文提出一种基于电源电流直接控制方法用于有源电力滤波器。采用基于瞬时无功功率的ip-iq检测法获得参考指令电流,该有源电力滤波器可以单独对谐波分量进行补偿,也可以对谐波和无功功率分量同时进行补偿。同时,提出的有源电力滤波器采用三电平变换器作为主电路结构,该三电平变换器适合于大功率和高电压应用场合,输出的电压电平数大于2,波形畸变小。所提出的控制策略具有控制结构简单,易于硬件实现的特点。通过具体的仿真表明所提出的方法控制效果良好,具有实际应用价值。更多还原

【Abstract】 For the wide application of the nonlinear loads and all kinds of converter equipments making the power system polluted with a mass of harmonic current, it is urgent to eliminate harmonic and improve power quality. As an ideal device to eliminate harmonic current and improve power factor, active power filter(APF) can compensate the harmonic and reactive power with variable both of frequency and amplitude, and it makes up the drawback of the passive power filter. Therefore, the development of active power filter is rapidly studied and has been applied in practice in some developed countries. Nowadays, in China, the exploitation of active power filter is at the stage of experiment and high power products have not been used up to now yet, so the research of active power filter has very important significance.Most of the previously proposed APFs are based on two-level converters and thus are suitable for low voltage use. However, in a high voltage system, there are no semiconductors devices capable of sustaining the desired voltage. Multilevel converters that provide more than two voltage levels, less distorted waveform and that have merits of low sustaining voltage, low switching losses, high efficiency and low EMI becomes the research focus of scientific and technological personnel.This paper applies one-cycle control to three-level two-leg three-phase three-wire APF. Based on the analysis of equivalent average modes in switching period, the key control equations are derived and circuit modes are created. The simulation results verify that three-level two-leg APF based on one-cycle control is simple and reliable, which make it be realized easily. The switch frequency of the main circuit is constant, and compensation performance is close to three-level three-leg three-phase three-wire APF based on one-cycle control.A novel control strategy is proposed for three-level APF based on direct source current control in this paper. With the ip-iq detecting method based on the instantaneous reactive power theory, reference current is to be get. Thus APF can compensate harmonic component, reactive power component respectively, harmonics and reactive power component together. In addition, the three-level converter that provides more than two voltage levels and less distorted waveform offers many benefits for higher voltage or higher power applications. This strategy needs simple controller, and is very easy to be implemented by the existing hard ware. The simulation results of an example show that proposed strategy has well control effect and can be used in practice.更多还原