新型广义有源电力滤波器的研究

发布时间：2018-04-02 18:29

本文选题：广义有源电力滤波器　切入点：谐波集中型优化PWM技术　出处：《哈尔滨工业大学》2014年博士论文

【摘要】：广义有源电力滤波器(Generalized Active Power Filter, GAPF)是一种采用电流间接控制的滤波器，其通过输出与电网同步的正序基波电压可以在不需要检测负载电流的情况下有效地实现无功补偿、谐波抑制、负序滤波及稳定电压等功能。GAPF虽然具有诸多优点，但亦存在如下缺点和局限：1.输出电压的频谱分布不集中；2.网侧滤波电抗的功耗过高；3.无功补偿精度与锁相精度低；4.不具备有功调节能力。本文对GAPF做了深入研究，，针对上述缺点和局限，在调制策略、拓扑结构、控制方法以及扩展功能等方面提出了一系列改善方法。传统GAPF采用特定消谐技术(Selective Harmonic Elimination Pulse Width Modulation, SHEPWM)。由于该技术的目的是根据具体需要来消除某些特定次数的谐波，故导致剩余谐波的含量大且分散，不易滤除。为改善GAPF输出电压的频谱分布，提高其性能，本文在SHEPWM的基础上提出谐波集中型优化PWM技术，使频谱中的剩余谐波集中在相邻的两个频次，以便通过单调谐滤波器加以滤除。为保证迭代的收敛性，提出一种逐步计算初始值的方法。研究结果表明，谐波集中型优化PWM技术可在相同开关频率下有效降低系统电流的谐波含量或网侧滤波电抗的容量与功耗。 GAPF在被提出时采用两电平逆变器，开关频率很低，输出电压的谐波含量大，且为抑制输出电压对系统电流的谐波污染，网侧滤波电抗需很大，导致功耗过高，这是其致命缺陷。为克服该缺陷，提出一种采用新型三电平拓扑结构的GAPF，其具有更好的安全性与实时性和更高的等效开关频率，可有效降低输出电压的谐波含量和网侧滤波电抗的容量与功耗；为提高装置的动态性能及避免负载电压的波动，提出调制比开环控制的方法，并推导了被控对象的小信号模型及PI参数的整定原则；为解决直流侧电压的平衡问题，提出一种定量计算小矢量占空比的方法，可实现中性点电压的精确调节。 GAPF的传统控制方法是调制比恒定的单环相位角控制。该方法虽然简单，但只能实现近似补偿，易产生过补或欠补现象。为克服上述缺陷，本文提出两种提高无功补偿精度的方法，可实现单位功率因数补偿。给出了关于无功补偿精度的定量分析；推导了被控对象的小信号模型及PI参数的整定原则；并比较了这两种方法的优缺点。传统GAPF通过过零检测电路与系统电压同步。该方法的动态性能差，且当系统电压不平衡或存在畸变时，无法检测出其中的正序基波的过零点，这会增强系统的非线性和降低系统的稳定性。为克服上述缺陷，本文提出基于dq变换的改进锁相环，大幅提高了动态性能和锁相精度。传统GAPF由直流侧电容和电压型逆变器组成，其本身是无源的，为保证输出电压的幅值，稳态时需要从系统吸收一定的有功功率以补偿自身损耗和维持直流侧电压，所以不具备有功调节能力。为提高性能和扩展功能，本文提出结合蓄电池储能系统(Battery Energy Storage System, BESS)的方案。详述了GAPF/BESS的拓扑结构及工作原理；建立了GAPF/BESS在dq坐标系下的数学模型；推导并比较了GAPF/BESS和GAPF的静态特性；针对蓄电池的两种不同接入方式提出了相应的控制方法和充放电模式，并给出了具体的流程图。为实际验证GAPF的有效性，搭建了一台三电平的实验样机；给出了无源元件的参数选择方法；提出了窄脉冲消除及死区补偿方法；针对文中的理论分析和控制方法做了一系列实验。
[Abstract]:Generalized active power filter (Generalized Active Power Filter, GAPF) is a kind of filter using indirect current control, the synchronization through the output and grid positive sequence fundamental voltage without the need to be able to detect the load current effectively realize reactive power compensation, harmonic suppression, negative sequence filter and voltage stability function of.GAPF has many but there are a lot of advantages, disadvantages and limitations: the spectrum distribution of the 1. output voltage from 2.; power network side filter reactance reactive power compensation is too high; 3. accuracy and precision of PLL is low; the 4. does not have the active adjustment ability. This paper makes a deep research on GAPF, aiming at the disadvantages and limitations of the modulation strategy. The topology structure, control method and extended function, put forward a series of improvement methods.
The traditional GAPF using selective harmonic elimination technique (Selective Harmonic Elimination Pulse Width Modulation, SHEPWM). Because the technology is designed to eliminate certain harmonic number according to the specific needs, so the content of residual harmonic is large and scattered, not easy to filter. In order to improve GAPF spectrum distribution of the output voltage, improve its performance in this paper SHEPWM is proposed based on Harmonic Concentrated PWM optimization techniques, the residual harmonic spectrum in frequency concentrated in two adjacent, in order to filter through the single tuned filter. In order to ensure the convergence of iteration, and proposes a method of calculating the initial value gradually. The results show that the capacity and power consumption of the harmonic content of the grid side the centralized optimization of PWM harmonic reactance filter technology can effectively reduce the system current at the same switching frequencies.
The GAPF two level inverter is introduced, the switching frequency is low, the harmonic content of output voltage, and to restrain the output voltage harmonic pollution to the current system, the network side needs great reactance filter, resulting in power is too high, this is the fatal flaw. In order to overcome the defects, put forward by a new three level the topological structure of the GAPF, it has better security and real-time and higher equivalent switching frequency, can effectively reduce the capacity and power consumption of the harmonic content and the network side filter reactance output voltage; in order to improve the dynamic performance of the device and avoid load voltage fluctuations, the modulation ratio method of open-loop control, and the small signal model and PI object parameters is the setting principle for solving problems; the balance of DC voltage, put forward a quantitative calculation of small vector duty ratio method, which can realize the precise regulation of the neutral point voltage.
The traditional GAPF control method is single loop phase modulation ratio constant angle control. The method is simple, but can only achieve approximate compensation, the over compensation or under compensation phenomenon. To overcome these drawbacks, this paper puts forward two methods to improve the accuracy of reactive power compensation, can realize the unit power factor compensation provides a quantitative. Reactive power compensation on the accuracy of analysis; small signal model and the parameters of PI derived object setting principle; and compares the advantages and disadvantages of the two methods. The traditional GAPF zero crossing detection circuit in synchronization with the system voltage. The dynamic performance of the method, and when the system voltage unbalance or distortion and can not detect the fundamental positive zero, this will increase the nonlinearity of the system and reduce the stability of the system. In order to overcome the above shortcomings, this paper proposes an improved phase-locked loop based on dq transformation, greatly improves the dynamic performance And the precision of phase lock.
The traditional GAPF by DC side capacitance and voltage type inverter, which is passive itself, to ensure that the amplitude of the output voltage, the steady state need to absorb a power from the system to compensate for their losses and to maintain the DC side voltage, so do not have the ability to adjust the active power. High performance and extended function, this paper combined with battery the energy storage system (Battery Energy Storage System, BESS). The scheme describes the topological structure and working principle of GAPF/BESS; the established GAPF/BESS model under DQ coordinates; the static characteristics of GAPF/BESS and GAPF is derived and; for two different access modes of battery and puts forward the corresponding control method and charge discharge model, and gives the flow chart in detail.
In order to verify the effectiveness of GAPF, a three level experimental prototype was built, and the parameter selection method of passive components was presented. The method of narrow pulse elimination and dead time compensation was proposed, and a series of experiments were carried out for theoretical analysis and control methods.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM761;TN713.8

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