【摘要】：近年來,隨著非線性負載設備廣泛使用于電力系統中,電網的諧波產生了十分嚴重的污染。目前抑制電網諧波和無功補償的主要裝置是有源電力濾波器,其關鍵環節是能夠實時準確的檢測諧波電流。目前諧波電流檢測有許多種方法,其中屬赤木泰文提出的“瞬時無功功率理論”應用最為廣泛。 基于瞬時無功功率理論的三相諧波電流檢測方法有p-q法、ip-iq法。其原理是將三相電路電壓和電流的瞬時值變換到α-β兩相正交的坐標系上進行研究。該方法能在三相電壓對稱且無畸變的情況下準確檢測出基波電流分量,但也存在著自身的局限性。例如在電網電壓畸變、三相電路不對稱時檢測存在誤差；不能直接應用于三相四線制電路；無法檢測出所需的特征次諧波電流等。 針對上述問題,本文進行了一系列的改進措施：無鎖相環檢測法省去了傳統檢測方法中的鎖相環電路,使檢測結果不受電壓畸變的影響：利用對稱分量法提取基波正序電壓,可以有效解決三相電壓不對稱造成的對基波有功電流檢測的影響；通過零序電流分離單元可提取出不對稱三相電流中的零序分量,使得諧波檢測能夠在三相四線制電路中得以應用。 此外,一種廣義瞬時無功功率理論的發展,突破了原有僅能檢測所有諧波電流之和的傳統理論,從而使故障中對應的特征次諧波電流檢測成為可能。在此基礎上,提出了一種基于廣義瞬時無功功率理論的任意次諧波電流檢測法。該算法在傳統ip-iq法的基礎之上,適當修改變換矩陣,檢測出三相不對稱系統中任意次諧波的正、負序分量,然后通過等價三角變換得到各相電流零序分量,三者相加即可得到所需的諧波電流。 最后,使用Matlab中的simulink軟件進行電路模型仿真和理論分析,并對檢測波形進行頻譜分析。結果表明,該算法具有很高的準確性和靈活度。
[Abstract]:In recent years, with the wide use of nonlinear load equipment in power system, harmonic generation of power network has caused serious pollution. At present, active power filter is the main device to restrain harmonic and reactive power compensation of power network. The key link of active power filter is to detect harmonic current in real time and accurately. At present, there are many methods for harmonic current detection, among which "instantaneous reactive power theory" proposed by Akimuki Tyrman is the most widely used. The three phase harmonic current detection methods based on instantaneous reactive power theory are p-q method and ip-iq method. The principle is to transform the instantaneous value of voltage and current of three-phase circuit into 偽-尾 two phase orthogonal coordinate system. This method can accurately detect the fundamental current component in the case of three phase voltage symmetry and no distortion, but it also has its own limitations. For example, when the voltage is distorted and the three-phase circuit is asymmetrical, the error can not be detected; it can not be directly applied to three-phase four-wire circuit; the characteristic subharmonic current can not be detected, and so on. In order to solve the above problems, a series of improvement measures are proposed in this paper: the phase-locked loop (PLL) circuit in the traditional detection method is eliminated and the detection results are not affected by the voltage distortion. The fundamental positive sequence voltage is extracted by using the symmetric component method. It can effectively solve the influence of the asymmetry of three-phase voltage on the detection of fundamental active current. The zero sequence component of asymmetrical three-phase current can be extracted by zero-sequence current separation unit, and harmonic detection can be applied in three-phase four-wire circuit. In addition, the development of a generalized instantaneous reactive power theory breaks through the traditional theory, which can only detect the sum of all harmonic currents, thus making it possible to detect the characteristic subharmonic current in fault. On this basis, an arbitrary harmonic current detection method based on generalized instantaneous reactive power theory is proposed. Based on the traditional ip-iq method, the transformation matrix is modified appropriately to detect the positive and negative order components of any order harmonics in a three-phase asymmetrical system, and then the zero sequence components of each phase current are obtained by equivalent trigonometric transformation. The harmonic current required can be obtained by adding the three. Finally, the circuit model simulation and theoretical analysis are carried out by using simulink software in Matlab, and the spectrum analysis of the detection waveform is carried out. The results show that the algorithm has high accuracy and flexibility.
【學位授予單位】：浙江大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM933.1

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