An Optimization-Based Algorithm for Shunt Active Filter Under Distorted Supply Voltages

In this paper, an optimization-based control algorithm for the compensation of steady-state load under distorted supply voltages is presented. For balanced and sinusoidal supply voltages, load compensation using shunt active filter produces perfect harmonic cancellation (PHC) and unity power factor (UPF) source currents. However, when the supply voltages are distorted, compensation for PHC will not provide UPF, as the harmonics in the supply voltages are not utilized for delivering the average power. In the same way, to achieve UPF source currents, the compensated source currents should have the same harmonics, unbalance, shape, and be in phase with the respective supply voltages, thereby violating the perfect harmonic cancellation objective. Hence, there should be an optimal operation between these two important compensation characteristics. The optimization-based control algorithm presented in this paper gives the best power factor while satisfying the constraints such as total harmonic distortion limits and average power balance of source currents. It is also flexible to adopt different compensation characteristics based upon the supply voltage conditions. Matlab and its optimization toolbox are used for simulation studies and solving the nonlinear optimization problem, respectively. The algorithm is validated by using a prototype of digital signal processor (TMS320F2812PGFA)-based shunt active power filter. Detailed experimental results are presented.     

一种有源滤波器的电流检测算法

有源滤波器能够实现良好滤波效果的关键在于可以准确实时地补偿谐波电流,这一点在很大程度上主要依赖于电流检测算法。文中在滑窗迭代离散时间傅立叶变换（DFT）算法的基础上,提出了基于自适应有限脉冲响应（FIR）预测算法和滑窗迭代离散时间傅立叶变换（DFT）算法相结合的电流检测算法,进行了Matlab的仿真实验,从采样时间离散程度、电网滤波效果以及系统稳定性等方面与基于滑窗迭代的离散时间傅立叶变换（DFT）算法相比较,验证了新算法的可行性与有效性。     

Three-Level Inverter-Based Shunt Active Power Filter in Three-Phase Three-Wire and Four-Wire Systems

This paper presents a direct current-space-vector control of an active power filter (APF) based on a three-level neutral-point-clamped (NPC) voltage-source inverter. The proposed method indirectly generates the compensation current reference by using an equivalent conductance of the fundamental component using APF's dc-link voltage control. The proposed control can selectively choose harmonic current components by real-time fast Fourier transform to generate the compensation current. The compensation current is represented in a rotating coordinate system with chosen switching states from a switching table implemented in a field-programmable gate array. In addition, a three-phase four-wire APF based on a three-level neutral-point-clamped inverter is also presented. The proposed APF eliminates harmonics in all three phases as well as the neutral current. A three-phase three-wire NPC inverter system can be used as a three-phase four-wire system since the split dc capacitors provide a neutral connection. To regulate and balance the split dc-capacitor voltages, a new control method using a sign cubical hysteresis controller is proposed. The characteristics of the APF system with an LCL-ripple filter are investigated and compared with traditional current control strategies to evaluate the inherent advantages. The simulation and experimental results validated the feasibility of the proposed APF.      

并联型有源滤波器空间矢量预测电流控制

为了提高有源滤波器(APF)的电流跟踪性能,本文采用电压空间矢量预测电流控制方法。该方法在当前采样时刻预测下一采样时刻的指令电流,计算出APF在下一采样时刻的输出端参考电压,再利用电压空间矢量调制得出控制开关信号,以达到电流跟踪控制目的。仿真实验表明,该方法具有更好的电流控制效果。     

A Predictive Control With Flying Capacitor Balancing of a Multicell Active Power Filter

Unlike traditional inverters, multicell inverters have the following advantages: lower switching frequency, high number of output levels, and less voltage constraints on the insulated-gate bipolar transistors. Significant performances are provided with this structure which is constituted with flying capacitors. This paper deals with a predictive and direct control applied to the multicell inverter for an original application of this converter: a three-phase active filter. To take advantage of the capabilities of the multicell converter in terms of redundant control states, a voltage control method of flying capacitor is added, based on the use of a switching table. Flying capacitor voltages are kept on a fixed interval, and precise voltage sensors are not necessary. The association of predictive control and voltage balancing increases considerably the bandwidth of the active filter.      

基于RLS自适应滤波器的并联型有源电力滤波器

将RLS自适应滤波器用于有源滤波器直流端电容电压的控制，并将直流端电容电压的控制完全摒弃了传统的PI积分控制，解决了控制参数难于调节且对电路中其他参数的变化非常敏感的问题。而且经过自适应滤波器的直流端电容电压几乎没有任何纹波，不但在电源电压为理想情况时可以起到较好的补偿作用，而且当电源电压发生畸变时也有较好的补偿性能。仿真研究证明了所提出的控制方法的正确性。     

Neural Network and Bandless Hysteresis Approach to Control Switched Capacitor Active Power Filter for Reduction of Harmonics

This paper proposes a combination of neural network and a bandless hysteresis controller, for a switched capacitor active power filter (SCAPF), to improve line power factor and to reduce line current harmonics. The proposed active power filter controller forces the supply current to be sinusoidal, in phase with line voltage, and has low current harmonics. Two main controls are proposed for it: neural network detection of harmonics and bandless digital hysteresis switching algorithm. A mathematical algorithm and a suitable learning rate determine the filter's optimal operation. A digital signal controller (TMS320F2812) verifies the proposed SCAPF, implementing the neural network and bandless hysteresis algorithms. A laboratory SCAPF system is built to test its feasibility. Simulation and experimental results are provided to verify performance of the proposed SCAPF system.     

有源电力滤波器调试

本文讨论和分析了有源电力滤波器的原理和控制结构。根据60kVA并联有源电力滤波器的调试过程,总结了有源电力滤波器调试的步骤,并给出60kVA并联有源电力滤波器的实验波形。     

基于单片机的有源电力滤波器控制算法的研究

有源电力滤波器的控制是影响其性能的重要因素,它主要是指令电流分离技术及控制算法的应用。为提高APF谐波检测速度和运行精度,通过对指令电流检测技术控制算法的讨论,分析了其对于APF系统性能产生的影响,采用补偿奇次谐波分量的方法,合理选择采样点的位置,提高了AFP系统的性能。     

利用无功元件平衡不对称有功负载的研究

对于三相四线制供电的配电系统中的单相负载,由于负荷消耗的随机性,经常会引起三相有功负载不平衡。本文提出了一种有效的方法,利用相量图分析了如何用纯电感和纯电容这两种无功元件平衡三相不平衡的有功负载。     

电容中点式有源电力滤波器数学模型及电流复合控制策略

三相四线并联型有源电力滤波器通常可用来补偿非线性负载所引起的谐波和无功电流,以及负载不平衡引起的负序或零序电流。本文描述了电容中点型三相四线有源电力滤波器在abc及dq0坐标系下的数学摸型,并由此给出了dq0同步旋转坐标系下的一种系统控制策略。由于有源电力滤波器指令为快速变化的交流谐波信号,传统的PI控制由于带宽有限,稳态精度较差。因此,提出了基于PI控制和重复控制并联的电流复合控制策略,利用重复控制对于周期扰动信号无差跟踪的特点来提高稳态精度,同时,PI控制又能保证良好的动态性能。仿真和实验结果验证该控制策略的可行性和有效性。     

电力电子变换器中滤波电容参数设计方法

在电力电子变换器中,滤波电容可以抑制电压脉动,消除谐波,其参数大小对变换器的性能有着重要影响。本文首先分析滤波电容器的特性,得出影响电容器滤波效果的各个因素,然后介绍了几种常用的滤波电容器参数设计方法,最后通过一个全桥变换器进行了仿真验证,有助于学生更好地掌握滤波电容器的参数设计。     

Steady-State and Dynamic Study of Active Power Filter With Efficient FPGA-Based Control Algorithm

A new approach using field-programmable gate array (FPGA) to implement a fully digital control algorithm of active power filter (APF) is proposed in this paper. This FPGA-based controller integrates the whole signal-processing function of an APF, including synchronous-reference-frame transform, low-pass filter, three-phase phase-locked loop, inverter-current controller, etc. By case studies on the principle, performance, and architecture, these control blocks are implemented in real-time and synthesized into a medium-scale FPGA chip by adopting some useful digital-signal-processing techniques, such as pipelining, folding and strength reduction, with respect to minimization of hardware resource and enhancement of operating frequency. As a result, the whole algorithm needs around 5000 logic elements and can run at synchronous system-clock rates of up to 65 MHz. Experimental results on a laboratory prototype are given to demonstrate performance of the proposed approach during steady-state and dynamic operations.     

应用于开关电源的有源共模EMI滤波器

在开关电源中,高速的开关造成了严重的共模噪声干扰。介绍了一种应用于开关电源的有源共模EMI滤波器。该有源滤波器基于电流检测、电流补偿的原理,以高速运放为核心。试验证明,该有源滤波器对共模噪声的抑制能力比无源器件高20dB。     

Novel Direct Current-Space-Vector Controlfor Shunt Active Power Filters Basedon the Three-Level Inverter

The growing number of electric drives with non-sinusoidal line currents has given increased interest in active power filters (APF), to avoid grid problems caused by harmonic distortions. In this paper, a novel direct current-space-vector control scheme (DCSVC) is presented for a three-level, neutral-point-clamped voltage source inverter, which is employed as an active power filter. The proposed method generates the compensation current reference indirectly generating an equivalent ohmic conductance for the fundamental component by means of the APF's dc-link voltage control. Based on the fast Fourier transform the compensation of the reactive fundamental current and selectable harmonics can be cancelled, confining the operation to only harmonic compensation and thus saving the APF's apparent power. The novel DCSVC, operating in synchronously rotating coordinates is implemented in a field programmable gate array, realizing the switching states from switching tables. The proposed control reduces the average switching frequency and thus, the switching power loss significantly, compared with a previous DCSVC, operating in stationary coordinates. Simulation and experimental results validate the feasibility and highly dynamic performance of the proposed control, both for harmonic and total non-active current compensation.      

局房有源滤波器故障原因分析

阐述了某局房安装的有源滤波器出现的故障现象,并对故障的产生原因进行分析和研究。     

有源电力滤波器在谐波治理中的应用

本文介绍了一个车间变电所内谐波污染的情况,叙述了并联型有源电力滤波器（APF）用于谐波治理的基本原理,并通过实际测量,说明了应用有源电力滤波器进行谐波治理的效果。     

An Implementation of an Adaptive Control Algorithm for a Three-Phase Shunt Active Filter

This paper deals with the hardware implementation of a shunt active filter (SAF) for compensation of reactive power, unbalanced loading, and harmonic currents. SAF is controlled using an adaptive-linear-element (Adaline)-based current estimator to maintain sinusoidal and unity-power-factor source currents. Three-phase load currents are sensed, and using least mean square (LMS) algorithm-based Adaline, online calculation of weights is performed and these weights are multiplied by the unit vector templates, which give the fundamental-frequency real component of load currents. The dc bus voltage of voltage source converter (VSC) working as a SAF is maintained at constant value using a proportional–integral controller. The switching of VSC is performed using hysteresis-based pulsewidth-modulation indirect-current-control scheme, which controls the source currents to follow the derived reference source currents. The practical implementation of the SAF is realized using dSPACE DS1104 R&D controller having TMS320F240 as a slave DSP. The MATLAB-based simulation results and implementation results are presented to demonstrate the effectiveness of the SAF with Adaline-based control for load compensation.      

多重化有源电力滤波器的研制

分析了多重化大功率有源电力滤波器的基本结构及控制系统的构成,采用一种基于负载基波电流作为参考电流的控制模式,提出了在该模式下多模块并联时的均流控制方法.应用该方法设计基于DSP和CPLD的数模混合控制系统,给出了采用该系统的二重化有源电力滤波器的实验结果,结果表明,能有效补偿非线性负载产生的谐波,具有很好的补偿效果.     

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。