Compensation characteristics of shunt active and series active power filters

Active power filters have been used in practice to suppress the harmonic interference in power systems. To compensate for harmonic currents of loads, active power filters usually are connected to power systems in parallel with the loads. These filters, which are called shunt active filters here, are very effective for loads that can be considered as current sources, such as thyristor rectifiers with large dc reactances. Many papers have covered the shunt active filters applied to these current-source loads, however, none has discussed characteristics of the shunt active filters when they are applied to voltage-source loads. On the other hand, since more and more diode rectifiers with capacitive dc filters have recently been used, harmonics generated by them have become an issue. The diode rectifier with capacitive dc filters behaves as a voltage source rather than a current source. When a shunt active filter is applied to such a diode rectifier, the current injected from the shunt active filter may flow into the diode rectifier. As a result, harmonics of the source current cannot be reduced effectively, and harmonic current flowing into the diode rectifier increases greatly. This paper presents the aforementioned problem of shunt active filters analytically and experimentally. Then a series active filter is proposed to suppress the harmonic current of the diode rectifiers. The features, operating conditions, and considerations of shunt active filters and series active filters are described analytically and demonstrated experimentally. Taking a diode rectifier with capacitive dc filter as a typical voltage-source load, compensation characteristics of shunt active filters and series active filters are discussed by experiment and simulation. The validity of the series active filters is illustrated experimentally.     

Harmonic current and voltage compensation using HSAPF based on hybrid control approach for synchronous reference frame method

This paper presents a Hybrid Series Active Power Filter (HSAPF) for compensation of source current and load voltage harmonics. The HSAPF combination consists of a small rated series active power filter and a shunt connected passive power filter. This combination is suitable for compensation of voltage-type as well as current-type harmonic producing load. The HSAPF uses the synchronous rotating reference frame method that based on hybrid control approach, which eliminate both source current as well as load voltage harmonics and also tests the performance of HSAPF for ideal voltage, non-ideal voltage and also at different loading conditions, etc.     

Overload prevention

This work presents a series active filter system for three-phase, four-wire distribution systems to alleviate the overloading of the neutral conductor. The active filter system employs a voltage sources inverter connected in series with a neutral conductor to suppress the excessive current harmonics. Theoretical analysis shows that series active filter system are more suitable than shunt active filter systems because most of the nonlinear load at low voltage levels are categorized as harmonic voltage source type. Laboratory test results show that the proposed system achieves desired filtering function.     

Experimental Verification of Photovoltaic-based Three-phase Four-wire Series Hybrid Active Power Filter

Abstract—This article proposes a photovoltaic and battery interfaced series hybrid active power filter, which is comprised of a series active power filter and an inductor-capacitor (LC) shunt passive filter. The main benefits of the proposed system provide the compensation against the voltage harmonics, current harmonics, and voltage interruption for the whole day. A series active power filter demands a source of energy for compensating the voltage sag/swell. The proposed topology utilizes the green energy source with an energy storage unit to meet the DC-link voltage requirement of the series active power filter. The control strategy is based on the dual formulation of the compensation system principles with adaptive fuzzy logic controller. The simulation and experimental studies are carried out to validate the effectiveness of the proposed photovoltaic interfaced three-phase four-wire series hybrid active power filter.     

A new combined system of active and passive filters to obtain harmonic compensation for large-capacity thyristor converters

Shunt passive filters, which are connected in parallel to harmonic-producing loads, have been used widely for harmonics suppression in power systems because of low cost and high efficiency. However, they have such inherent problems as series and parallel resonance. On the other hand, shunt active filters, which are also placed in parallel, have such an inherent problem as initial and running costs are high compared with those of shunt passive filters. To solve these inherent problems in shunt passive and shunt active filters, the authors have proposed a combined system of a shunt passive filter and a small rated series-active filter. The purpose of this paper is to reduce the required rating of the series-active filter, considering a practical application of the combined power filter to harmonic compensation for large-capacity thyristor converters. The points are summarized as follows:

• 1 The required rating of the series-active filter can be reduced less than one-tenth by connecting a series-resonant circuit in parallel to the secondary of current transformer.
• 2 It is clarified theoretically and verified experimentally that compensation characteristics of the new combined system are equivalent to those of the already-proposed system with no series-resonant circuit.

     

基于有功能量平衡原理的并联型有源滤波器的控制方法

介绍了一种基于有功能量平衡原理的并联型有源滤波器的控制方法。首先分析了并联型有源滤波器在补偿阻感负载时,瞬时有功和瞬时无功在系统中的传递过程。接着从有功能量平衡原理的角度,提出了通过对直流侧电压反馈进行PI调节,来获得整个系统所需的输入有功分量方法。这种方法无需复杂谐波检测,只需检测两路电源电流信号和一路电压信号,从而使整个控制系统得以简化。最后通过仿真和实验对提出的方法进行了验证,实验表明这种方法具有较好的谐波补偿效果。     

一种新型混合有源滤波器及其复合控制策略设计

混合有源滤波器是一种有效的谐波抑制方式。电力系统中谐波源负载种类繁多,特性各异,针对目前应用最为广泛的三相整流桥负载,在以往混合滤波器研究的基础上,提出了一种新型单调谐混合滤波器,对其无源滤波部分依据有源部分容量最小的原则进行了设计,并对其工作原理进行了详细的分析研究。针对所设计的混合滤波器的特有结构,设计了其复合控制策略。该复合控制策略在不影响系统稳定性的基础上,提高了系统的滤波性能,保证了有源滤波器小容量下良好的运行性能。对所设计的复合控制器在频域和时域内进行了稳定性分析。仿真和实验结果验证了所提出的拓扑结构和复合控制策略的有效性。     

一种实用的串并联混合有源电力滤波器

设计了一种实用的串并联混合有源电力滤波器,分析了其结构、工作原理和滤波性能。在该滤波器中,串联在系统和谐波负载之间的零磁通变流器可自动对基波呈低阻抗、对谐波呈高阻抗,从而实时检测出剩余谐波电流流过变流器时产生的谐波电压降、实现滤波;逆变器可产生一个与检测到的谐波电压成正比的电压。通过将耦合变压器与无源电力滤波器串联后并入电网,减少了流入系统的谐波电流。实验结果验证了该滤波器设计原理的正确性,表明其能有效降低滤波器有源部分的容量,具有良好的滤波性能。     

注入式混合有源电力滤波装置研制及工程应用

为了弥补并联型混合有源滤波器(HAPF)中的有源部分需承受较大电网基波电压而难以用于中高压电网的缺点,通过添加基波谐振支路并使其与有源部分并联从而减小它的基波分压,同时通过系统中的无源滤波器组来补偿大容量无功功率,使整个系统能够同时抑制电网谐波和补偿无功功率.针对某冶炼厂大型整流装置谐波抑制和无功补偿的工程需要,在对比了不同的解决方案之后,分别就不同的工况详细介绍了兼具大容量无功静补能力的并联混合型有源滤渡器装置的研制、工程应用过程中的关键技术和主要组成设备,仿真和现场应用效果证明了该装置能够在不同工况下治理谐波达标和补偿无功功率至设定值,系统能够满足实际工程应用中从电网中高压侧着手提高供电功率因数、滤除谐波电流从而节能降耗的需要.     

Combined system of a series active filter and a shunt passive filter—an optimum design of the shunt passive filter

The combined system of a series active filter and a shunt passive filter that is proposed by the authors has the ability to eliminate a major disadvantage of shunt passive filters, namely, harmonic amplification. The series active filter needs a much smaller kVA rating than a conventional shunt active filter, and as a result, the combined system has good filtering characteristics and high efficiency. This paper presents an optimum design of the shunt passive filter that makes possible a great reduction in the required kVA rating of the series active filter. It can minimize the peak voltage across the series active filter and reduce the required kVA rating of the filter to 60 percent. A computer simulation geared to practical applications of large three-phase. twelve-pulse thyristor rectifiers is used to compare the compensation characteristics of the optimized system with those of a combined system that uses a conventional shunt passive filter. Experimental results obtained with a laboratory model of the filter corroborate the design approach.     

一种新型的并联混合型有源电力滤波器

提出一种新型的基于阻抗可控的并联混合型有源电力滤波器。通过对带气隙的线性变压器的电压方程分析得知，当变压器二次侧注入的补偿电流和一次侧的电流满足一定的补偿条件时，变压器对谐波电流呈现近似为零的低阻抗，对基波电流呈现连续无极可调的电抗。从而不仅能够有效地抑制谐波，与无源电力滤波器相结合，还能够实时补偿无功功率。针对该原理提出一种新型的指令电流运算方法。此新原理在高压交流电力系统柔性输电装置中将有着广阔的应用前景。实验结果证明此有源电力滤波器新原理的正确性。     

谐波源与有源电力滤波器的补偿特性

通过分析电网中的典型谐波源,说明了整流器直流侧电感或电容滤波时,其特性类似谐波电流源或电压源。在探讨并联型和串联型APF工作原理的基础上,研究了它们对不同谐波源的补偿特性。从而说明对电流型或电压型谐波源进行谐波补偿,应该分别使用并联型或串联型APF。否则,不能起良好的补偿效果。     

改进并联混合型有源滤波器在大功率非线性负载中的应用

提出了一种改进型并联混合型有源滤波器.针对非线性负载产生的主要谐波分量,将逆变器与无源滤波器电感并联设计,利用并联滤波电感的分流作用以降低逆变器电流容量、输出电压频率和开关频率,并在逆变器发生故障时滤波器仍能正常工作.针对单次谐波电流检测,应用了一种改进滑动窗算法.仿真和试验结果表明,该混合型有源滤波器不仅具有良好的滤波效果,而且能减少逆变器电流.     

三相四线制下中线谐波电流治理的新方法

提出了一种中线谐波电流治理的新结构，该结构由新型无源滤波器和有源滤波器串联构成。其中无源滤波器包括3次、9次单调谐滤波器和高通滤波器，每个滤波支路都由三相电容器连接成星形后与一个电感（高通滤波器中还有一个并联电阻）串联构成。电网中的非零序电压全部由电容器承担，同时，流经无源滤波器电感和有源滤波器中的电流仅为谐波电流，大大降低了有源滤波器的容量和成本。文中分析了其基本原理：当有源滤波器输出一定的电压时，不仅可以使零序谐波电流完全流入滤波器中，而且可以抑制系统零序谐波电压产生谐波电流，从而使电网侧中线中仅含基波电流。文中提出了一种简单的控制方法，它仅利用电网侧零序谐波电流作为控制信号来产生有源滤波器所需的驱动信号。最后，利用PSCAD／EMTDC进行了仿真验证，仿真结果表明该结构中的有源滤波器的容量较小而且滤波效果较好。     

配电网串并联复合有源电力滤波器的仿真研究

分析了并联型和串联型电能质量补偿器分别补偿负荷电流和电源电压的缺陷及原因，介绍了串并联复合有源电力滤波器（SPAPF）同时补偿电网畸变电压和抑制负载谐波电流的运行机理，提出了适合于SPAPF的电源畸变电压参考量比较检测法、负荷谐波电流dqo检测法以及一种改进的稳定直流电容电压的PI控制策略。仿真结果验证了分析的正确性与设计方案的有效性。     

An indirect current control of hybrid power filter for varying loads

This paper presents an indirect current control scheme of parallel hybrid power filter system (PHPF) with self-supporting dc bus to eliminate harmonics generated by the nonlinear load. The PHPF system consists of a shunt passive filter with an active filter (AF) in series with it connected at the point of common coupling (PCC) in parallel with nonlinear load. The AF is realized using a three-phase voltage source inverter (VSI) with self supported dc bus. The compensation principles and dynamics of the system are discussed in detail. A proportional-integral (PI) controller over average dc bus voltage of the AF connected in series with passive filter is used for the control of the PHPF. The modeling equations of the PHPF are derived for compensation of harmonics generated by a three-phase rectifier load. The effectiveness of proposed control technique of the PHPF is demonstrated through simulated results under the dynamics of change of loads.     

双电源交错备用型通用电能质量控制器

传统的通用电能质量控制器(GPQC)直流侧如果没有储能装置,则无法实现不间断供电;即使直流侧装设储能装置,蓄电池储能或超级电容器储能都存在补偿时间、补偿容量及使用寿命均有限等问题。为此提出了一种由两个并联变换器和两个串联变换器构成(每一个并联变换器和串联变换器都通过一个直流电容交错的连接在一起)的新双电源交错备用型通用电能质量控制器(DPS-GPQC)和一种简单有效的控制策略。DPS-GPQC能够同时补偿电网谐波电压、电压跌落和上升、电压中断、三相电压不平衡、谐波电流及无功电流,且能够实现两个不同电源之间能量的交错备用。基于MATLAB/SIMULINK的仿真结果表明了DPS-GPQC良好的性能和所提控制策略的有效性。因此,所提结构既能同时解决两个不同系统的大多数电能质量问题,又可以有效提高电力系统的供电可靠性。     

一种35kV大容量无功补偿与谐波抑制综合系统

为解决广西某变电站的谐波和无功等电能质量问题,本文提出一种35kV大容量无功补偿与谐波抑制综合系统,采用无源滤波器与有源电力滤波器混合的结构,无源部分补偿无功功率,有源部分和无源部分共同抑制谐波。本文分析了综合系统的拓扑结构和补偿原理,提出了电压外环、电流内环的双闭环控制策略,保证综合系统有源滤波器的直流侧电压稳定和实现谐波抑制与无功补偿功能,并对无源滤波器组和有源滤波器分别采取了有效的保护措施,现场运行结果验证了系统的有效性。     

Network conditioners on the basis of active filters

A novel control scheme for the stabilization of load voltage and the compensation for high harmonics of load current in series-type active power filter systems combined with shunt-type active power filters is proposed. The control system allows an effective correction of power factor, harmonic distortion, and load voltage regulation.     

有源滤波器在不同网络中的应用分析

介绍了并联型有源滤波器对谐波抑制的作用。基于电压检测控制的并联型有源电力滤波器相当于一个有源阻尼,对谐波分量呈现出阻抗特性,除了具有抑制谐波进入电网的能力之外,还能阻尼谐波共振。将并联型有源电力滤波器应用于两种不同类型的电力线网络,然后评估其在不同类型网络结构中的滤波和阻尼共振的性能。第一种电力网为220 V配电网,第二种电力网为简化的150 k V太阳能发电网络,容量为444.4 MVA。并且使用谐波共振模态分析和计算参与因数的方法来确定有源滤波器的最佳安置位置,使有源滤波器滤波和抑制共振的效果最优。