Interleaved Buck Converter Based Shunt Active Power Filter with Shoot-through Elimination for Power Quality Improvement

The “shoot-through” phenomenon defined as the rush of current that occurs while both the devices are ON at the same time of a particular limb is one of the most perilous failure modes encountered in conventional inverter circuits of active power filter (APF). Shoot-through phenomenon has few distinct disadvantages like; it introduces typical ringing, increases temperature rise in power switches, causes higher Electromagnetic Interference (EMI) and reduces the efficiency of the circuit. To avert the “shoot-through”, dead time control could be added, but it deteriorates the harmonic compensation level. This dissertation presents active power filters (APFs) based on interleaved buck (IB) converter. Compared to traditional shunt active power filters, the presented IB APFs have enhanced reliability with no shoot-through phenomenon. The instantaneous active and reactive power (p-q) scheme and instantaneous active and reactive current component (id-iq) control scheme has been implemented to mitigate the source current harmonics. Type-1 and Type-2 fuzzy logic controller with different membership functions (MFs) viz. Triangular, Trapezoidal and Gaussian have been implemented for the optimal harmonic compensation by controlling the dc-link voltage and minimizing the undesirable losses occurred inside the APF. Additionally, the adaptive hysteresis band current controller (AHBCC) is being implemented to get the nearly constant switching frequency. The performance of the control strategies and controllers for the presented IB APF topologies has been evaluated in terms of harmonic mitigation and dc-link voltage regulation under sinusoidal, unbalanced sinusoidal and non-sinusoidal voltage source condition. This dissertation is concerned with the different topologies of 3-phase 4-wire IB APFs viz. split capacitor (2C) topology, 4-leg (4L) topology, transformer based full-bridge IB APF or single capacitor based FB IB APF (1C 3 FB IB APF) and full-bridge IB APF (FB IB APF) for low to medium power application. Moreover, APF topology is now being expanded to multilevel VSIs for high power application. Thanks to flexible modular design, transformerless connection, extended voltage and power output, less maintenance and higher fault tolerance, the cascade inverters are good candidates for active power filters with the utility of high power application. The cascaded FB IB APF is modelled with no shoot-through phenomenon by using multicarrier phase shifted PWM scheme. Extensive simulations have been carried out in the MATLAB / Simulink environment and also verified in the OPAL-RT LAB using OP5142-Spartan 3 FPGA to support the feasibility of presented IB APF topologies, control strategies and controllers during steady and dynamic condition. The performance shows that IB-APF topologies bring the THD of the source current well below 5% adhering to IEEE-519 standard. A comparison has also been made, based on SDP (switch device power) between the IB-APF topologies

FPGA Implementation of digital controller for shunt active power filter to reduce harmonics and reactive power

Most of the pollution issues created in power systems are due to the non-linear characteristics and fast switching of power electronic equipment. Power quality issues are becoming stronger because sensitive equipment will be more sensitive for market competition reasons, equipment will continue polluting the system more and more due to cost increase caused by the built-in compensation and sometimes for the lack of enforced regulations. Efficiency and cost are considered today almost at the same level. Active power filters have been developed over the years to solve these problems to improve power quality. Among which shunt active power filter is used to eliminate and load current harmonics and reactive power compensation. The active power filter (APF) is implemented with PWM based current controlled voltage source inverter (VSI). This VSI switching signals are generated through proposed three-level hysteresis current controller (HCC) that achieves significant reduction in the magnitude and variation of the switching frequency; it is indicating improved performance compared to 2-level HCC. The shunt APLC system is modeled and investigated under different unbalanced non-linear load conditions using MATLAB programs. The simulation results reveal that the active power filter is effectively compensating the current harmonics and reactive power at point of common coupling. The active power line conditioner system is in compliance with IEEE 519 and IEC 61000-3 recommended harmonic standards. Due to non-linear characteristics the load current gets distorted which causes undesirable effects like heating, equipment damages, EMI effects etc. in power network. The active power filter (APF) is the best solution for eliminating the harmonics caused by the non-linear loads. This work presents the three-phase four-wire active filter for power line conditioning (PLC) to improve power quality in the distribution network and implementation of a digitally controlled APF. Designed in Hardware Description Language (VHDL or VERILOG), the controller becomes independent of process technology. Synchronous reference frame is used for generation of reference current. PI currents algorithm and hysteresis current controller (HCC) together is written in VHDL code and is implemented using FPGA platform. Various simulation results are presented under steady state and transient state condition and performance is analyzed. Simulation results obtained shows that the performance of three phase system with APF is found to be better and digital controller add a new aspect for the controller from low cost, high speed and hardware implementation point.PWM and hysteresis based current control is used to obtain the switching signals to the voltage source inverter(VSI)

Active Power Filters in Zero Energy Buildings

Master's thesis Renewable Energy ENE500 - University of Agder 2017With an increasing focus on the environment and moving from fossil to renewable energy, there has and is an increasing interest in zero energy buildings. Zero energy buildings often utilize local intermittent renewable energies such as wind and solar energy, and are going to play an important role in the smart grid development with their distributed generation and energy storage etc. In Southern Norway, the smart village Skarpnes is utilizing building integrated photovoltaic systems and is developed for studying zero energy buildings and its impact on electricity demand and power quality. Power electronic based equipment such as uninterruptible power supplies, adjustable speed drives, personal computers and more have all enhanced our daily lives by providing an efficient and reliable way of utilizing the electrical energy. Because of their non-linear behaviour, they are responsible for harmonic currents causing additional losses and harmful effects. In this thesis, a shunt active power filter based on the instantaneous power theory used for power quality improvement is studied. This involves harmonic current, reactive power and neutral current compensation, where load data is obtained from the smart village Skarpnes project. Investigating the operation of the shunt active power filter during import and export of power, during load changes and operation during distorted and unbalanced utility voltage. Based on simulations using MATLAB/Simulink the three-phase, four-wire shunt active power filter is able to compensate the harmonic currents, reactive power and neutral current. The total harmonic distortion in the source current after compensation is below limits proposed by the Institute of Electrical and Electronics Engineers Standard 519-2014 for all test case

Harmonic current extraction of shunt active power filter based on prediction current technique - Hysteresis PWM

Due to the wide spread of power electronics equipment in modern electrical systems, the increase of the harmonics disturbance in the ac mains currents has became a major concern due to the adverse effects on all analysis and simulation using MATLAB-SIMULINK of a three-phase shunt active equipment. This paper presents the Shunt Active Power Filter (SAPF) to compensate the generated harmonics by 3-phase Rectifier Bridge fed R-L load. The harmonic current extraction is based on prediction current extraction technique -hysteresis PWM generation pattern

Adaptive-Fuzzy Controller Based Shunt Active Filter for Power Line Conditioners

This paper presents a novel Fuzzy Logic Controller (FLC) in conjunction with Phase Locked Loop (PLL) based shunt active filter for Power Line Conditioners (PLCs) to improve the power quality in the distribution system. The active filter is implemented with current controlled Voltage Source Inverter (VSI) for compensating current harmonics and reactive power at the point of common coupling. The VSI gate control switching pulses are derived from proposed Adaptive-Fuzzy-Hysteresis Current Controller (HCC) and this method calculates the hysteresis bandwidth effectively using fuzzy logic.  The bandwidth can be adjusted based on compensation current variation, which is used to optimize the required switching frequency and improves active filter substantially. These shunt active power filter system is investigated and verified under steady and transient-state with non-linear load conditions. This shunt active filter is in compliance with IEEE 519 and IEC 61000-3 recommended harmonic standards

A Comprehensive Survey on Different Control Strategies and Applications of Active Power Filters for Power Quality Improvement

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Power quality (PQ) has become an important topic in today’s power system scenario. PQ issues are raised not only in normal three-phase systems but also with the incorporation of different distributed generations (DGs), including renewable energy sources, storage systems, and other systems like diesel generators, fuel cells, etc. The prevalence of these issues comes from the non-linear features and rapid changing of power electronics devices, such as switch-mode converters for adjustable speed drives and diode or thyristor rectifiers. The wide use of these fast switching devices in the utility system leads to an increase in disturbances associated with harmonics and reactive power. The occurrence of PQ disturbances in turn creates several unwanted effects on the utility system. Therefore, many researchers are working on the enhancement of PQ using different custom power devices (CPDs). In this work, the authors highlight the significance of the PQ in the utility network, its effect, and its solution, using different CPDs, such as passive, active, and hybrid filters. Further, the authors point out several compensation strategies, including reference signal generation and gating signal strategies. In addition, this paper also presents the role of the active power filter (APF) in different DG systems. Some technical and economic considerations and future developments are also discussed in this literature. For easy reference, a volume of journals of more than 140 publications on this particular subject is reported. The effectiveness of this research work will boost researchers’ ability to select proper control methodology and compensation strategy for various applications of APFs for improving PQ.publishedVersio

Key technologies of active power filter for aircraft: a review

Active Power Filter (APF) is not only an advanced technology to improve power quality and purify power system pollution but also a good approach to solve electrical problems of an advanced aircraft such as harmonic, reactive power and unbalanced load. However, there are still some specific problems for the application of aeronautic APF in practice. Based on current research on aeronautic APF, this paper reviews three key technologies where APF can be used in aircraft AC power supply system, including the acquisition method of reference current, the strategy of APF current control and the main circuit topology.  Consecutively, the features of current aeronautic APF research are summarized, and the future research directions are also suggested

Three Phase Active Shunt Power Filter with Simple Control in PSIM Simulation

Generally the electrical system used by many consumer and industry usually uses passive filter and capacitor bank to compensate, harmonics and reactive power absorbed by the loads .The passive filter and capacitor bank make harmonic resonance with input impedance so that magnitude of harmonic current increased with harmonic frequency generated by nonlinear load. In this paper a simple active filter with PSIM simulation model used, the reference current generated by simple method of power synchronous detection and gate pulses generated by the use of modulated hysteresis current controller. The proposed model compensates current harmonics, and it  does power factor correction. The active filter designed in PSIM software and control of active filter is done in Simulink environment. PSIM and MATLAB software is linked by Sim coupler. The capacitor voltage is maintained constant by using PI controller. Simulation results with PSIM software shows that the designed active filter is very effective in harmonic elimination and power factor correction Keywords: : Active filter, Modulated Hysteresis current control, power synchronous detection (PSD),current harmonics, Pulse Width Modulation, , PSIM software

Power Angle Control Scheme for Integration of UPQC in Grid Connected PV System

The quality of electric power is greatly affected by the proliferation of non-linear loads in electrical energy processing applications like switched mode power supplies, electric motor drives, battery chargers, etc., The custom power devices like UPQC has gained more importance in power quality arena as it gives the best solution for all power quality issues. UPQC is the combination of both shunt and series active power filters connected through a common DC link capacitor. The shunt active power filter is the most corrective measure to remove the current related problems, power factor improvement by supplying reactive power and regulates DC link voltage. The series APF acts as controlled voltage source and corrects voltage related problems, like sag or swell, flickering, harmonics, etc.,. As a combination of both of these, UPQC improves service reliability. In the present work, shunt inverter control is based on modified active- reactive (p-q) power theory, uses High selectivity filter (HSF) for reference current generation. The series APF uses Power Angle Control (PAC) scheme for compensating sag/swell, interruption and voltage related problems along with sharing a part of load reactive power demand with shunt APF and thus ease its loading and makes the utilization of UPQC to be optimal. The topology uses three phase three leg inverters for both shunt APF and series APF. The gating signals were generated using Hysteresis controller. The output of High step-Up DC-DC Converter is used to work as DC voltage source for both APFs. The input voltage for the converter is provided by Photo Voltaic array incorporated with P&O MPPT technique. The use of high step-up DC-DC converter is for high voltage gain with better efficiency. The present topology avoids the PLL in shunt active power filter. The simulation results are presented to show the effectiveness of the three phase, three-wire PV-UPQC and here obtained an acceptable THD for source current and kept load voltag