应用并联型有源滤波器抑制雷达电源的谐波

针对雷达电源工作时产生的谐波电流对电网污染严重的情况，提出了采用并联型有源电力滤波器来抑制雷达电源工作时产生的谐波电流。首先分析了并联型有源电力滤波器的工作原理和基于傅里叶变换理论的谐波电流检测算法；然后介绍了采用二重化方案设计的主电路以及相应控制电路，最后给出了实验结果。实验证明，无论雷达电源工作在稳态还是脉动方式，并联型有源电力滤波器能有效抑制其工作时产生的谐波。     

Discrete Frequency Tuning Active Filter for Power System Harmonics

Severe voltage distortion, due to power system harmonic resonance, has been reported in recent years. This issue becomes more significant in high penetration of a photovoltaic (PV) network. A conventional voltage detection active filter operates as similar conductance for all harmonic frequencies to resolve this problem whether in a fixed conductance command or in an automatic gain adjustment control. However, its filtering capability is impeded by the mismatch between the active filter and the radial line, and the voltage distortion may still be significant. This paper proposes a discrete frequency tuning active filter to suppress power system harmonics. The active filter operates as variable conductance for each individual harmonic frequency. Each harmonic conductance is dynamically adjusted according to the corresponding harmonic voltage distortion of the active filter installation point in response to increase or decrease of nonlinear loads, or variation of resonant frequency in the power system. The mismatching problem between the feeder impedance and the active filter can be avoided effectively. Therefore, harmonic voltage distortion can be maintained at an allowable level throughout the feeder with lower peak current and lower rms current of the active filter, and loads installed at various locations of the power system receive more uniform voltage waveform.     

A passive series, active shunt filter for high power applications

This paper presents a hybrid series passive/shunt active power filter system for high power nonlinear loads. This work is motivated by the fact that the ability of a converter to perform effectively as an active filter is limited by the power and the frequency distribution of the distortion for which it must compensate. This system is comprised of a three-phase shunt active filter and series AC line smoothing reactance installed in front of the target load. The proposed system significantly reduces the required shunt active filter bandwidth. The space-vector pulse width modulation (PWM) controller is based on a dead-beat control model. It is implemented digitally using a single 16-bit microcontroller. This controller requires only the supply current to be monitored, an approach different from conventional methods. The paper provides background on the operation of the filter, the details of the power circuit, the details of the control design, representative waveforms, and spectral performance for a filter which supports a 15 kVA phase controlled rectifier load. Experimental data indicate that the active filter typically consumes 2% or less of the average load power, suggesting that a parallel filter is an efficient compensation approach. The spectral performance shows that the active filter brings the system into compliance with IEEE519-1992 up to the 33rd harmonic for an AC line smoothing reactance of 0.13 p.u     

无变压器型混合有源滤波器及其控制策略研究

在对一种无变压器型混合有源滤波器的电路拓扑和参数设计方法进行分析研究的基础上,提出一种采用电网谐波电流作反馈控制与负载谐波电流作前馈控制的复合控制策略,并用SIMULINK建立仿真模型进行仿真分析。通过与仅采用电网谐波电流作反馈控制时的仿真结果进行比较,可以看出使用这种复合控制方法,能更有效地抵消电网中的谐波电流,降低总的谐波畸变率。     

AC line voltage harmonics compensator with excessive current control

We investigate an instantaneous common terminal voltage-controlled harmonics compensator constructed by a shunt active filter with an appropriate series inductance including the line impedance. This compensator can reduce or compensate both the ac line voltage distortion derived from the downstream utility source voltage harmonics and the upstream current harmonics by nonlinear loads at the same time. The control system can be easily constructed without directly detecting the common terminal voltage to be compensated. Therefore, the main circuit configuration and the control system are simple. The harmonics compensation level and the compensation current can be easily adjusted by changing the feedback gain for the sensing inductance voltage drop. In this paper, we describe the basic principle of the control method, the modified control method, the circuit construction by the pulsewidth-modulation-controlled shunt active filter and the control system of the compensator. Then, we show some operating waveforms for the cases of the downstream voltage distortion and the upstream harmonics current from the nonlinear loads by simulation analysis and experiments to verify the feasibility.     

Control and performance of a fully-digital-controlled shunt activefilter for installation on a power distribution system

This paper presents a fully-digital-controlled shunt active filter for harmonic termination of a power distribution system. The main purpose of the active filter based on voltage detection is not to compensate for current harmonics but to damp out harmonic propagation caused by line inductors and shunt capacitors for power factor correction. However, time and phase delays inherent in digital controllers might lead to unsatisfactory harmonic-damping performance although digital controllers are preferable to analog controllers. This paper deals with the design and implementation of a digital controller for a shunt active filter based on voltage detection. Experimental results obtained from a laboratory system developed in this paper verify the viability and effectiveness of the fully-digital-controlled active filter     

A 6.6-kV transformerless shunt hybrid active filter for installation on a power distribution system

This paper presents a fully-digital-controlled shunt hybrid filter for damping of harmonic propagation in power distribution systems. The harmonic propagation is caused by resonance between line inductances and power capacitors installed for power factor correction. A possible solution to damping out harmonic propagation is based on installation of a shunt pure active filter at the end of a feeder. This paper proposes a shunt hybrid active filter characterized by series connection of a seventh-tuned LC filter per phase and a small-rated three-phase active filter. Like the pure filter, the hybrid filter is connected to the end bus of a feeder. The capacitor of the LC filter imposes a high impedance to the fundamental frequency, so that the fundamental voltage appears across the capacitor. This unique feature allows us to directly connect the hybrid filter to the 6.6-kV power line without step-down transformers. Furthermore, the capacitor used in this hybrid filter is lighter, cheaper and smaller than the transformer used in the pure filter. Theoretical analysis, along with experimental results obtained from a 200-V, 20-kW laboratory system, verifies the viability and effectiveness of the proposed hybrid filter.     

A simple frequency-independent method for calculating the reactiveand harmonic current in a nonlinear load

A basic criterion that determines the behavior of an active power filter is the method of calculating the reference current. There are many ways of generating this reference, but the methods are generally complex and hard to tune. This paper describes a simple and effective method for calculating the reference current necessary to feed a shunt active power filter to compensate the power factor and harmonic currents generated by a nonlinear load. Simulations and experimental results are presented, showing that the proposed circuit may operate at frequencies ranging from 40 to 65 Hz without adjustment     

并联混合型有源电力滤波器的仿真研究

并联混合型有源电力滤波器能很好地补偿谐波源产生的谐波。文中有源滤波器主电路采用3“H桥”共用一个电容的形式。利用MATLAB中的Simulink模块对并联混合型有源电力滤波器进行建模仿真,并对仿真结果进行分析。     

基于瞬时无功功率理论的APF的研究与仿真

本文介绍了并联型有源电力滤波器的工作原理和基于瞬时无功功率理论的谐波和无功电流检测方法,用Matlab SimUlink建立了带典型负载的电力有源滤波器的仿真模型,模拟实际系统,用于检验其策略和参数在实际条件下的工作情况。仿真模型的结果表明：基于瞬时无功功率理论的有源滤波器,可以很好的起到动态抑制电网谐波和补偿无功的作...     

Compact Left-Handed Transmission Line as a Linear Phase–Voltage Modulator and Efficient Harmonic Generator

We construct a synthetic left-handed transmission line with cascaded varactors and shunt inductors. By modulating dc bias, the capacitance of the varactors can be changed and modulation of the output phase state is possible. For frequencies from 4.7 to 6.4 GHz, a very linear phase variation versus voltages of over 200deg phase variation with low insertion-loss variation (plusmn0.5dB) is demonstrated. This circuit can also act as an efficient harmonic generator when a large signal is applied. Since the left-handed transmission line shows high-pass filter response, harmonics generated are not seriously attenuated. However, because this synthetic transmission line is a very dispersive medium, strong dispersions and instabilities may arise. The circuit size is determined by the diode size and lumped-element inductor, allowing it to be compact     

一种适用于RFID阅读器的新型自动增益调节电路

为了提高射频识别(RFID)阅读器中接收机的动态范围,并实现对贴有标签目标物体的跟踪,在分析传统自动增益控制模块的基础上,设计了一种适用于RFID接收机的大动态范围自动增益调整电路,电路结构简单.基于ADS软件的仿真结果表明:该电路能够根据输入信号的功率水平自动地调整其增益,输入动态范围高达80 dB,自动增益调节范围...     

有源滤波器的保护及运行过程研究

串联型有源滤波器的主电路、控制电路出现故障或负载发生短路等情况下如何正确保护整个系统将是滤波装置能否正常运行的一个关键问题。文中叙述了三种保护方案,给出了基于基波磁通补偿的串联混合型有源滤波器的主电路及其电气控制图,结合保护具体讨论了该系统有源和无源部分的投入切除问题。     

Stability analysis of a series active filter integrated with adouble-series diode rectifier

This paper deals with a harmonic current-free AC/DC power conversion system which is characterized by the integration of a small-rated series active filter with a large-rated double-series diode rectifier. The stability of the active filter based on feedback control is discussed theoretically, taking into account delay time in the control circuit. As a result, it is revealed that the delay time may produce a bad effect on stability, especially when the power conversion system is installed on a stiff power system with low system inductance. The authors propose a viable way of reducing the effect of delay time on the system stability. Analysis in the frequency domain enables us to know how much the system stability is improved in terms of gain and phase margins. A switching-ripple filter is designed to obtain good filtering performance without affecting the system stability. Experimental results obtained from a 20 kW laboratory system verify the validity of the developed theory, and confirm the viability and effectiveness of the proposed control circuit     

Shunt active power filter synthesizing resistive loads

The paper discusses the use of a shunt active power filter to compensate for the line current distortion and to improve the power factor. The advantages of the resistive load synthesis over the sinusoidal current synthesis when the filter is used in a system where the voltage is not perfectly sinusoidal are presented. The control circuit is based on analogic multipliers, and the currents follow the same waveforms of the respective line voltages. Experimental results of connecting a three-phase active power filter to a nonsinusoidal grid are presented     

空间矢量脉宽调制在有源滤波器中的应用

文章针对典型的三相整流电路中产生的谐波对电网产生的影响,研究易于数字化的SVPWM,将其应用于并联有源电力滤波器内层跟踪控制中,给出一种补偿功能较为完善的并联有源电力滤波器及其控制方法。仿真结果表明：SVPWM调制用于并联有源滤波控制可以明显改进补偿的动态性能,提高滤波效果。     

The Use of Genetic Algorithms for the Design of Resonant Compensators for Active Filters

Resonant compensators appear to be suitable for active power filter control, where the compensator needs to track harmonic currents accurately. However, to ensure stable operation and robustness to parameter uncertainties they require considerable design effort. This paper describes the use of a genetic algorithm for the optimization of the parameters of a resonant controller employed for the control of current in a shunt active filter. The optimization process takes into account variations of the power system parameters to provide an optimum solution in terms of both speed of response and robustness. Experimental results confirm the effectiveness to the approach.      

新型三相三线制并联有源滤波器的滑模控制方法

为了提高有源滤波器的谐波补偿效果,设计了一种新型滑模控制器,用于三相三线制并联有源滤波器的参考电流跟踪控制.谐波电流检测方法采用基于瞬时无功功率理论的谐波电流检测方法,能快速、准确的检测出负载电流中的谐波分量.直流侧电压控制方法采用PI控制方法实现.Simulink仿真结果显示,与传统的滞环比较控制方法相比,所设计的新型滑模控制方法能够有效的降低跟踪误差,提高有源滤波器的谐波补偿效果.     

Digital Repetitive Control of a Three-Phase Four-Wire Shunt Active Filter

Shunt active power filters have been proved as useful elements to correct distorted currents caused by nonlinear loads in power distribution systems. This paper presents an all-digital approach based on a particular repetitive control technique for their control. Specifically, a digital repetitive plug-in controller for odd-harmonic discrete-time periodic references and disturbances is used for the current control loops of the active filter. This approach does not introduce a high gain at those frequencies for which it is not needed and, thus, improves robustness of the controlled system. The active power balance of the whole system is assured by an outer control loop, which is designed from an energy-balancing perspective. The design is performed for a three-phase four-wire shunt active filter with a full-bridge boost topology. Several experimental results are also presented to show the good behavior of the closed-loop system     

三相四线制无功与谐波全补偿的并联有源电力滤波器的研究

简要分析了并联有源电力滤波器的工作原理,选取含有裂相电容的三桥臂电压源型逆变器作为系统主电路,输出电流采用动态滞环控制。针对三相四线系统,且考虑到电网电压畸变和不对称的情况,给出了一种基于瞬时功率理论实现无功功率和谐波全补偿的控制策略,并使用Matlab对系统进行了仿真。