Application Of Shunt Active Power Filter Research Articles

Power Quality Enhancement of Grid-Connected Renewable Systems Using a Matrix-Pencil-Based Active Power Filter

Power electronic converters are used for integrating renewable energy sources such as wind and photovoltaic into the grid. This integration gives rise to many challenges in power systems, especially regarding power quality. Indeed, integrated systems generate a non-linear current full of harmonics, which degrades power quality. Active power filters are usually used to compensate for these harmonics at the point of common coupling. In the control of active power filters, harmonics need to be extracted from the non-linear current. In this paper, the matrix pencil method―a model-based technique for estimating parameters of exponentially damped or undamped sinusoids in noise―is proposed to extract the reference signal in shunt active power filter applications. The performance of the proposed matrix pencil method is studied for current harmonic compensation and power factor correction under different modulation schemes and two DC links: an external DC voltage source and a capacitor. Using a capacitor for the DC link requires not only including a proportional-plus-integral controller to maintain a constant capacitor voltage, but also accounting for the loss current in the formulation of the matrix pencil method. Compared with the instantaneous reactive power theory and synchronous reference frame, results obtained from simulated data using MATLAB/Simulink under different loading conditions show that the proposed method corrects the power factor and affords a lower source current total harmonic distortion and fast response.

Performance Analysis of Three-Phase Shunt Active Power Filter for Harmonic Mitigation

Aims: To carried out performance analysis of a shunt active power filter (SAPF) for harmonics mitigation.
 Study Design: Experimental design through simulation studies using P-Q Theory and proportional integral controller.
 Place and Duration of Study: Department of Physics, Nasarawa State University Keffi, main campus, Nigeria, between October 2020 and September 2021.
 Methodology: Primary and secondary data were obtained using AVO Digital Multimeter and manufacturers’ datasheets from Schneider electric website to capture required system parameters, SAPF was designed using a Voltage Source Inverter model to represent the Three-Phase source, and P-Q Theory with PI Control was used for reference current extraction. The SAPF was modeled, designed and simulated using MATLAB-Simulink and analyzed under different nonlinear load conditions and harmonic spectrum to achieve low Total Harmonic Distortion (THD).
 Results: The THD in the unbalanced system voltages before the application of SAPF was found to be 12.6%, 11.4% and 11.2%, while after the application of SAPF was 2.2%, 2.5% and 2.5% for phase voltages a, b and c respectively. The grid currents indicated THD of 27.2%, 30.9% and 31% before application of SAPF and 2.2%, 2.2% and 2.1% after application.
 Conclusion: The use of non-linear loads; has adverse effects on the quality of electric power as well as phase voltage and frequency waveforms. The use of SAPF is of vital importance in improving electric power quality for reliable power supply and quality service delivery.

A model-based controller for a single-phase n-level CHB multilevel converter

This work introduces a generalized methodology for mathematical modelling and controller design of a single-phase cascaded H-bridge multilevel-converter comprising the connection of N H-bridges, which results in 2N+1 voltage levels. Towards this end, the average model of the converter is first transformed into a decoupled mathematical structure based on a new definition of state variables. Out of this, the control objectives, current tracking and voltage regulation, are decoupled from the voltage balance problem for such a general case of N H-bridges. To show the benefits of the proposed methodology, a shunt active power filter application has been considered in this paper, where the control objectives are the compensation of the power factor and harmonic distortion due to nonlinear loads, plus regulation and balance of all DC-bus voltages. In particular, this work focus on the balance issue, which leads to the design of N-1 balance loops. A tuning strategy is also introduced to design the gains of the proposed control scheme, which are based on time scale separation and a desired closed-loop transient performance. The proposed generalized methodology is evaluated in a 7-level cascaded H-bridge converter both through simulations and experimentally.

Computational intelligence based control of cascaded H-bridge multilevel inverter for shunt active power filter application

This work proposes computational intelligence based control of five-level cascaded H-bridge inverter (5LCHB) for an application of shunt active power filter (SAPF) to reduce total harmonic distortion (THD) in supply current under nonlinear loads. Active and reactive power (PQ) method is used to extract reference currents. The proposed controller is effectively verified for three different carrier based pulse width modulation methods such as phase disposition (PD), phase opposition disposition (POD) and alternate phase opposition disposition (APOD). The required rules for fuzzy logic controller (FLC) are set by human brain computation. The performance of computational intelligence based FLC is implemented and is verified for reduction of THD under nonlinear loads. The DC voltage balance is achieved using the proposed controller. The proposed work is carried out in the environment of Matlab Simulink. The comparative performance analysis of THD in source current, individual harmonics (5th, 7th, 11th, and 13th), power factor (PF), real power, and reactive power compensation (RPC) for APOD, POD and PD using both PI and FLC are presented.

Adaptive Space-Vector Hysteresis-Based Control with Constant Switching-Frequency for Three-Level Shunt Active Power Filters

This paper proposes a new constant-frequency space-vector hysteresis current control (CF-SVHCC) technique for three-level neutral-point diode-clamped (TL-NPC) inverters in shunt active power filter applications when applied to three-phase isolated neutral point (INP) systems. The proposed techniques is developed based on two recognized modulation methods, space-vector pulsewidth modulation and adaptive hysteresis-band current control. The proposed technique consists of two alternating adaptive hysteresis-band strategies around the error-current vector in the $$\alpha \beta $$ stationary reference frame (SRF). The first strategy is designed with the purpose of utilizing the medium- and large-voltage vectors of the TL-NPC inverter to keep the error-current vector within the adaptive hysteresis boundary, while the second one is designed according to the small-voltage vectors of the TL-NPC inverter to balance its neutral point voltage. The main part of this proposed technique is a supervisory controller that operates in SRF to effectively avoid inter-phase dependency. This smart controller systematically uses the zero-voltage vectors and the nonzero-voltage vectors associated with the alternating adaptive hysteresis-band strategies in order to prevent high switching frequency and maintain the switching frequency constant in INP systems, respectively. The proposed CF-SVHCC performance is validated by extensive simulation studies for both steady-state and transient conditions.

Implementation of FFT Algorithm using DSP TMS320F28335 for Shunt Active Power Filter

This work presents simulation, analysis and experimental verification of Fast Fourier Transform (FFT) algorithm for shunt active power filter based on three-level inverter. Different types of filters can be used for elimination of harmonics in the power system. In this work, FFT algorithm for reference current generation is discussed. FFT control algorithm is verified using PSIM simulation results with DLL block and C-code. Simulation results are compared with experimental results for FFT algorithm using DSP TMS320F28335 for shunt active power filter application.

Comprehensive optimisation and practical design of LCL filter for shunt active power filter

Shunt Active Power Filter (SAPF) can be applied to compensate for existing source-type current harmonics. However, high-precision compensation is difficult because harmonic current has a large variation and the current loop has a steady-state error. A design method for a new practical LCL filter based on SAPF is proposed in this paper. A harmonic model of the LCL filter is built based on SAPF application. The changing relationship between the parameters of the filter and harmonic frequency is then examined. The suitable values for the parameters are determined based on the precondition of having a split ratio of 1, the limit scope of LCL resonance frequency and the ratio of the capacitance branch’s impedance parameter in combination with the relationship curve of the inductance parameter ratio and harmonic frequency as well as the respective requirements of the LCL regarding the attenuating properties of lowand high-frequency bands. Finally, the validity and feasibility of the design method are verified by conducting an experiment with SAPF’s industrial prototype.

Improving Performance of Shunt Active Power Filter with Hysteresis-Based Direct Current Control using Particle Swarm Optimisation

Shunt active power filter (SAPF) is a well-established and widely accepted power electronic device for cancelling harmonic currents from electrical networks. The common configuration of SAPF utilises a proportional-plus-integral (PI) controller. However, the conventional approaches for determining the PI coefficients may not provide satisfactory results for a wide range of operating points (loads). This paper proposes to use the particle swarm optimisation (PSO) algorithm to determine the optimal coefficients of PI controller for SAPF applications. The DC control approach is used to generate the reference harmonic signals from the non-sinusoidal load current while a hysteresis-based PI controller is selected to control the compensating currents. Simulation results for a power network connected to a non-linear load are generated to investigate the dynamic performances of SAPF with the conventional-PI and enhanced PSO-PI controllers.

Real-time implementation of adaptive fuzzy hysteresis-band current control technique for shunt active power filter

Optimising the performance of power system networks using conventional methods is quite difficult because of the complex nature of systems that are highly non-linear and non-stationary. In this study a hybrid adaptive fuzzy hysteresis current controller for shunt active power filter (SAPF) is proposed. The conventional adaptive hysteresis concept is hybridised with fuzzy logic controller (FLC), which facilitates discarding of uncertainty in the system. In fact, conventional proportional-integral (PI) controllers for shunt active filter are based on a linearised model that fails to react under transient events. On the other side, FLC has widened its applicability to many engineering fields and offers satisfactory results for a wide variety of operating conditions. It helps in fulfilling the need for perfection, such as stability and robustness for every system. All this motivated to adopt FLC for SAPF applications. By incorporating an adaptive fuzzy hysteresis band, active power filter (APF) gains outstanding compensation ability under steady-state and transient conditions. To validate the proposed approach, the system is implemented on a real-time digital simulator and adequate results are reported for its verification.

An HIL-Based Reconfigurable Platform for Design, Implementation, and Verification of Electrical System Digital Controllers

This paper presents a top-down design flow for design, implementation, and verification of digital controllers associated with electrical systems. In the proposed design flow, the functional description of the studied system and the detailed electronic hardware design and validation of the digital controller are performed using a hardware-in-the-loop (HIL)-based reconfigurable platform in a unique design environment. The way of using this design flow and the reconfigurable HIL platform is analyzed through a fault-tolerant shunt active power filter application. The experimental results obtained with a laboratory prototype fault-tolerant active filter demonstrate the performances and the efficiency of the proposed design flow and HIL-based reconfigurable platform.