total harmonic distortion (THD)

Inverter is an important topology in modern power electronic system which provides a solution to convert the average power flow from DC power to AC power. Inverter employs different soft switching techniques to solve the problems faced in industrial applications such as harmonic reduction , stress reduction and switching power loss minimization. This paper presents the detailed study and comparative analysis of inverter and multilevel inverter.

Variable Speed Drives (VSD) due to their high dynamic performances are growing importance in industrial
applications. PWM inverters are mainly responsible for VSDs dynamic operation but they give rise to
bearing currents. Parasitic capacitances present in machine doesn’t create problem at lower frequencies, but at higher carrier frequencies they provide charging path and builds up shaft voltage. When this voltage reaches to a dielectric breakdown voltage of lubricant film, it breaks down, and develops a high discharge bearing current which damage the bearings in a very short time of operation. Multilevel inverter is one of the options to reduce this problem. This paper is an attempt to investigate the effects on CMV, bearing voltage, bearing currents and total harmonic distortion (THD); by diode clamped multilevel (three, five and seven level) and conventional inverter fed induction motor. In this paper phase disposition (PD), sinusoidal pulse width modulation (SPWM) technique is used.

This work presents investigation of passive filter performance on three-phase inverter with 180° conduction mode. The simulation model ofthe inverter is developed  by  using  MATLAB/Simulink.  The  power  circuit  used  Insulated Gate  Bipolar  Transistor  (IGBT)  as  switching  device.  The  inverter  is controlled  by  using  bipolar  Sinusoidal  Pulse  Width  Modulation  (SPWM) technique. The IGBT  was set to 25kHz for switching frequency  (fs). Three types of passive filters which are LC, RC and PI filters are used to investigate the ability to remove the unwanted signal that occurred on the inverter. The result is analyzed based on the performances of output filter in term of Total Harmonic  Distortion  in  voltage  (THDv),  current  (THDi),  shape  of  output voltage and current. The THD must be less than 5% at rated inverter output voltage  or  current  by  referring  to  IEC  61727 Standard.  The  passive  filter  is modeled in MATLAB/Simulink environment to study the characteristics and performance of the filters.

ABSTRAK PT XYZ merupakan salah satu perusahaan ban terbesar di dunia, dimana listrik merupakan salah satu energi paling vital yang dibutuhkan guna memenuhi kebutuhan produksi. Terdapat beberapa faktor yang dapat mempengaruhi kualitas daya listrik, salah satunya adalah harmonisa. Harmonisa sendiri merupakan sebuah kecacatan gelombang yang disebabkan oleh interaksi antara gelombang sinusoidal sistem dengan komponen gelombang lain yang mempunyai frekuensi kelipatan bilangan asli ganjil dari komponen fundamentalnya. Harmonisa ini memiliki dampak yang buruk bagi sistem kelistrikan apabila keberadaanya terlalu besar dan berada diluar standar. Keberadaan harmonisa sendiri telah diatur dalam standar yaitu IEEE 519 – 1992, yang juga menjadi standar yang berlaku didunia kelistrikan internasional saat ini. Sedangkan di PT XYZ sendiri keberadaan harmonisa masih diluar standar IEEE 519 – 1992, karena belum ada perlakuan khusus untuk menangani gejala tersebut. Oleh karena itu penulis melakukan penelitian untuk merancang filter yang mampu digunakan untuk menanggulangi besarnya nilai harmonisa diperusahaan ini. Dalam penelitian ini penulis merancang beberapa jenis filter pasif, yaitu single tune filter, single tune filter yang dimodifikasi menggunakan trafo, dan low pass filter. Beban yang digunakan sebagai sumber harmonisa untuk penelitian ini adalah lampu hemat energi, lampu hemat energi memiliki nilai harmonisa yang cukup tinggi. Perancangan filter dilakukan dengan cara melakukan identifikasi terhadap beban terlebih dahulu, kemudian menentukan desain filter yang akan dirancang, setelah itu melakukan simulasi perancangan filter pada software PSIM baru kemudian melakukan perancangan filter pada beban sesungguhnya dengan menggunakan komponen yang sebenarnya. Dari hasil penelitian didapatkan hasil bahwa seluruh filter yang dirancang mampu menurunkan harmonisa, akan tetapi kemampuanya berbeda – beda untuk tiap – tiap filternya. Kemudian berdasarkan simulasi dan perancangan yang telah dilakukan, penulis memilih single tune filter sebagai filter terbaik yang dirancang dalam penelitian tugas akhir ini, dan yang paling cocok diterapkan untuk mereduksi nilai harmonisa di PT XYZ. Kata Kunci : Harmonisa, IEEE 519 – 1992, PSIM, filter pasif.

This paper deals with the design of cascaded 11 level H- bridge inverter. It includes a comparison between the 11 level H-bridge and T-bridge multilevel inverter. The cascaded inverter of higher level is a very effective and practical solution for reduction of total harmonic distortion (THD).These cascaded multilevel inverter can be used for higher voltage applications with more stability. As the level is increased the output waveform becomes more sinusoidal in nature. The inverter is designed using multicarrier sinusoidal pulse width modulation technique for generating triggering pulses for the semiconductor switches used in the device. Through this paper it will be proved that a cascaded multilevel H-bridge topology has higher efficiency than a T-bridge inverter, as whichever source input voltage is provided since input is equal to the output voltage. In T-bridge inverter, the output obtained is half of the applied input, so efficiency is just half as compared to H-bridge. The output waveform is distorted and has higher THD.  The simulation is performed using MATLAB /Simulink 2013 software.

Cascaded H-bridge Multilevel Inverter (MLI) is most efficient topology for medium and high voltage DC-AC conversion, having less output harmonics and less commutation losses. Disadvantages are their complexity, more number of power devices, passive components and a complex control circuitry. Here a Cascaded Hybrid Multilevel Inverter is used to produce a three phase 9-level output voltages. Now a day inverter is also know as a DC-AC converter, is one of the most popular part of electrical device. This proposed inverter widely used in industries application such as speed control of induction motor. This thesis focus on three phase 9-level bipolar and unipolar switching inverter with characteristics like output voltage boosting ability and also we discus about the bipolar and unipolar switching scheme along with capacitor voltage control. The modified topology uses Cascaded H-bridge (CHB) with bidirectional and unidirectional switches producing boost up output voltage. Here a hybrid Pulse Width Modulation (PWM) technique is applied to control the power devices. This modulation technique uses a sine wave and a repeating wave, these waves are combined and a complete reference wave is generated. There is comparative study between CHB and modified topology between number of power devices used and Total Harmonic Distortions (THD). THD of modified topology is reduced and analyzed by FFT window. The results are observed by MATLAB/SIMULINK software.

This paper is based on the improvement of power quality (PQ) using fuel cell and fuzzy based controller. By using the proposed controller, the quality of power in the grid system especially in micro grid connected with non-linear and unbalanced load is enhanced. The configuration of the system is combined with hybrid arrangement of photovoltaic ([PV) with wind energy conversion system (WECS), fuel cell (FC) including the compressed air energy storage system (CAES) where the power management is controlled by using the distributed power sharing technique. In this proposed system the distortions in voltage at point of common coupling (PCC) is decreased by using the FC which acts as compensator in hybrid system. Reference current is developed which depends on real and reactive power of the source connected to the compensator. Based on demand of power for nonlinear load, without using any external communication interfaces, the proposed control theory can change the modes of operation and can compensate the unbalance in the system which is caused due to single-phase micro sources and load changes. The complete productive design of the micro-sources and power electronic converters are presented in the paper. The operation and performance of the proposed controller used in microgrid is validated through simulation in MATLAB/Simulink environment.

ABSTRAK Krisis energi listrik yang melanda indonesia menyebabkan beberapa persoalan dalam bidang ketenagalistrikan, sehingga dilakukan upaya untuk mengatasi krisis energi listrik, dengan melakukan peningkatan efisiensi dari peralatan yang digunakan konsumen. Salah satu upaya yang dilakukan pemerintah dan pihak swasta (produsen lampu) untuk meningkatkan efiesiensi lampu Neon dan lampu hemat energi serta lampu LED menggantikan fungsi lampu pijar. Lampu Hemat Energi dan Lampu LED memiliki tingkat efesiensi penerangan bagus, akan tetapi lampu LED Lampu Hemat Energi (LHE) dan lampu TL memiliki beberapa karakteristik diantaranya menghasilkan distorsi harmonisa arus dan tegangan. Tujuan dilakukan penelitian untuk mengetahui pengaruh THDi dan THDv dengan metode pengukuran. Hasil dari pengujian THDi yang muncul pada kombinasi sejenis rata-rata THDi muncul 130% pada LED, pada kombinasi sejenis LHE THDi yg muncul sebesar 124% semakin menurun bila jumlah beban ditambah, pada kombinasi sejenis TL THDi yang muncul sebesar7,5%.Untuk kombinasi beban LED//LHE nilai THDi yang muncul dengan rata-rata sebesar 125%, kombinasi beban LED//TL THDi yang muncul turun hingga 105%, kombinasi beban LHE//TL THDi yang muncul turun hingga 82%, kombinasi LED//LHE//TL nilai THDi turun sebesar 80% dibanding hanya kombinasi LED//LHE. Adapun kombinasi dua jenis beban dan tiga jenis beban THDv yang muncul rata-rata 2%.

This article uses an analytical tool called dist-space to examine the structural role of guitar distortion in hard rock and heavy metal. Dist-space facilitates categorizing, comparing, and graphing the changes in a composition’s distortion structure, which demonstrate distortion’s capacity to generate motivic and formal structures. An application of Robert Morris’s generalization of contour theory, dist-space couples sequential time to a sequentially ordered dimension of discrete distortion regions whose foundation is the distortion function F(A)=D and spectral analysis. While the process of categorizing, comparing, and graphing distortion sounds is partially subjective, the distortion function F(A)=D underlying dist-space’s sequentially ordered dimension of distortion regions provides an objective foundation for measuring, identifying, and comparing distortion sounds that informs subjective judgments leading to greater intersubjective agreement between theorists, analysts, and performers. Although the primary analytical focus of the dist-space tool is guitar distortion, it has a wider range of applications. For example, it can provide analytical insights into the distortion sounds recording engineers produce from microphones, tape machines, and digital or analog signal processing, which have become an integral process of producing tracks in a studio. In fact, this study demonstrates that the guitar distortion heard on recordings is often a product of both guitar amplification and recording studio techniques.

— This paper presents Simulation and displaying of 6-pulse and 12-pulse multi-pulse converter topologies. In this paper multi-pulse converters are created for improving quality of power, to lessen harmonics in AC main and ripple in DC side output. The 6-pulse and 12-pulse rectifier can regularly found in Adjustable speed drives and in HVDC systems. Multi-pulse converter recompenses the impact of harmonics by utilizing phase shifting transformer. Design of 6-pulse, 12-pulse, 18-pulse and 24-pulse converters have been displayed alongside with their Circuit diagram and waveforms. The voltage waveforms have been watched and Total Harmonic Distortion approach has been computed. This path isn't the same as customary approach in light of the fact that here autotransformer is configured by utilization of a few linear transformers. For high-power applications, a 12-pulse, 18-pulse and 24-pulse setup are helpful to diminish the harmonics, however regardless of everything, it consolidates the (np±1) th (n: integer, p: pulse) harmonics.

One of the major electrical load on a utility grid is industrial, street and residential lightings. To enhance the energy efficiency and as a measure of energy conservation, incandescent lamps (IL) are replaced with the modern lights. Replacing incandescent lamps with compact fluorescent lamp (CFL) and fluorescent lamp (FL) is one of the measures taken by the authorities to reduce the energy consumption and enhance energy efficiency. Both the CFLs and LEDs are the sources of harmonics as electronic circuits are used in for their ignition. These harmonic sources adversely affect other loads connected to the same bus. It also affects the grid in terms of high reactive power demand (due to poor power factor), distortion in currents and hence overall degrading the power quality. Power quality measurements such as power factor, voltage and current total harmonic distortion (THD) are done and reported in this paper. Different scenarios are considered with full and partial replacement of incandescent lamps. A comprehensive comparison between incandescent, CFL and LED are made in terms of these power quality measurements. From the result analysis, it is noted that, the CFL consumes less active power than incandescent. But, the THD is considerably higher in CFL than incandescent. While comparing LED and CFL, the power factor of LED is found poor compared to CFL. The simulation and experimental approaches are used in this work.

TRIASO es una empresa mediana industrial dedicada a la elaboración de plantas de asfalto y trituradoras. En la gran mayoría de su proceso se requiere el uso de la energía eléctrica, ya que en su carga instalada predominan motores, rectificadores, controles numéricos por computadora, entre otros. Para lograr la identificación de alguna problemática u oportunidades de ahorro de energía eléctrica se realizó una evaluación general en la planta, incorporando el uso de los diagnósticos energéticos tipo uno y tipo dos, de acuerdo con la metodología impartida por DESMB. El objetivo del proyecto fue diseñar una propuesta integral del correcto funcionamiento de la instalación eléctrica en la empresa TRIASO mediante la corrección de los niveles de iluminación, la implementación de un filtro armónico y el cálculo de las perdidas por efecto joule, con el propósito de lograr un ahorro en el consumo eléctrico. De igual forma para hacer una planeación en busca de eficiencia energética se optó por utilizar la metodología de los Sistemas de Gestión de la Energía (ISO 50001). Al implementar la propuesta de iluminación se obtendría un ahorro anual de $44,153.14, reduciendo así el consumo en iluminación para la nave industrial en un 48%, con un TIR de 6.27 años. De igual manera se analizó la factibilidad de instalar un filtro para reducir el % THD I, proponiendo así un FPNS con un TIR de 1.41 años y un filtro activo con un TIR 6.62 años, en ambos el ahorro anual es de $90,039.64.

Cet  article  décrit  la  méthodologie  d'améliorer  la qualité de  puissance à l'extrémité de charge dans  un système
photovoltaïque  PV connectée au réseau électrique basse tension.
La cellule photovoltaïque transforme l'énergie solaire en énergie électrique. L’énergie solaire est  naturellement disponible dans l’abondance et non pollue une des sources les
plus  prometteuses.
Les  causes des  problèmes de la qualité  de la puissance  comme la déformation des ondes de (tension/courant) par les harmoniques, dégradation de facteur de  puissance à affecté  les réseaux  électriques aussi bien que les secteurs de service.Cet article traite la conception et la simulation d'un tel type de filtre active. Des modèles  de simulation du filtre active shunt (parallèle) ont été faits.

This paper analyzed three-level Cascaded H-bridge Multilevel Inverter (CHMLI) utilizing two modulation techniques namely Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM). The performance and the output of CHMLI in terms of Total Harmonic Distotion (THD) % and circuits complexity were compared. The simulations models were constructed using MATLAB/SIMULINK. The results showed the CHMLI produced the lowest THD contents and utilized fewer components. Moreover, the SVPWM produced less THD than SPWM.

Sinusoidal pulse width modulation or SPWM is widely used in power electronics. To digitize the power so that a sequence of voltage pulses is generated by ON or OFF of the power switches the pulse width modulation inverter has been the main alternative in power electronic for many years as a result of its circuit simplicity and rugged control scheme SPWM switching technique utilized in used in industrial applications SPWM techniques are characterized by constant amplitude pulses is completely different dutycycle for each period the width of this pulses are modulated to obtain inverter output voltage control to diminished its harmonic content ,Sinusoidal pulse width modulation or SPWM is that technique to used in motor control and Inverter application in this thesis development a unipolar and bipolar SPWM voltage modulation type is given as a result of this method offers the advantage of effectively doubling the changed frequency of the Inverter voltage making the output filter smaller cheaper and easier to generate with this signal triangle wave as a carrier signal is compared to the sinusoidal wave whose frequency is the desired frequency. In this thesis single-phase inverters and there in operation principles are analyzed very well the concept of sinusoidal Pulse Width Modulation or PWM for inverters is explain with analyses extended to different kinds of SPWM strategies.

This paper briefly discusses various types of inverters
and the output waveforms of square wave inverter and SPWM
inverter. FFT analysis is performed on the outputs obtained for
SPWM inverter. The variation in THD by varying the
Modulating Index and Carrier Frequency is also included.

The losses in European Union distribution transformers are estimated at about 33 TW · h/year, whereas reactive power and harmonic losses add a further 5 TW · h/year. The reduction of distribution transformer no-load loss is particularly important as the ratio of no-load to load losses is nearly three. In this paper, the no load operation of wound-core transformers under sinusoidal and distorted supply-voltage conditions is investigated. For that purpose, a 2-D nonlinear transient finite-element analysis taking into account hysteresis has been developed. The hysteresis model is based on a modified Jiles–Atherton representation, and the proposed analysis is compared to experimental data.

This paper proposes an analytic study of SEPIC (Single-Ended Primary Inductor Converter) converter by employing Hysteresis Current Control and PI control technique to observe Output Voltage Stability, Total Harmonic Distortion (THD), Power Factor (PF) and Efficiency. SEPIC converter is extensively used in battery operated equipment for its significant feature of stepping up and stepping down voltage without changing polarity. The paper focuses on modeling SEPIC converter in CCM (continuous conduction mode) mode. State-Space Average technique is deployed to model the system mathematically and to implement the PI controller. Satisfactory performance is achieved by adopting both Hysteresis Current Control and PI control. Hysteresis current control method shows THD of 2.798% and efficiency of 90.07% whereas PI control method depicts THD of 17.17% and efficiency of 88%. Power Factor of 0.966 is achieved for PI controller while hysteresis current control method shows a power factor of 0.8208. PSIM software has been used for simulation purpose and the total investigation is analyzed for both methods.

A modified multilevel inverter (MLI) structure has been presented for Photovoltaic (PV) fed 2.3 kV micro-grid applications. To feed the cascaded multilevel micro-grid connected inverter (CM-MGCI) voltage, a PV array is designed considering the environmental effects of Bangladesh. We have estimated the performance of the classical and a modified cascaded H-bridge (CHB) MLI with level-shifted carrier sinusoidal pulse width modulation (LSC-SPWM) technique in MATLAB/Simulink environment. The voltage and total harmonic distortion (THD) profile for the proposed eleven-level modified H-bridge MLI topology has been compared with the conventional CHB topology. The harmonic profile has also been compared with other modified MLI topologies. Compared to the conventional CHB and other recent modified MLI topologies, the proposed H-bridge CM-MGCI shows better THD profile.

In this study, a modified carrier is proposed to generate PWM gating signal. Proposed PWM method reduces total harmonic distortion (THD) of the output voltage of inverter up to 5.8% than the traditional triangular carrier based PWM. Major harmonic components in output voltage are less in magnitude when proposed PWM technique is applied to inverter. Fundamental component of output voltage is also higher in proposed PWM method for all modulation index and frequency ratio. Performance of proposed modified carrier based PWM is evaluated by MATLAB simulation for single phase 4-cells 9-levels cascaded H-bridge MLI.

In this work, the phase shifted carrier pulse width modulation (PSC PWM) technique is applied as the most favorable modulation scheme for a photovoltaic (PV) fed cascaded multilevel-micro-grid connected inverter (CM-MGCI), with consideration of the total harmonic distortion (THD) of the output voltage. In addition to this, a modified PSC PWM method named as variable amplitude PSC-PWM (VA-PSC-PWM) is proposed. To verify the performance of proposed PSC PWM method, MATLAB/Simulink simulations are performed with nine-level CM-MGCI. To feed the CM-MGCI required voltage, a PV array is designed and a maximum power point tracking (MPPT) technique is demonstrated in MATLAB/Simulink environment. From the voltage profile of VA-PSC-PWM technique, it is observed that the proposed method gives better THD profile than classical PSC PWM method. Our proposed modified PSC-PWM also provides better THD profile compared to other recently proposed PSC-PWM technique.

The world today has seen a rise in power demand with the expansion in industry and technology. Coal powered plants alone cannot meet this, due to the harmful emissions and greenhouse gases emitted, which are a contributor to heating. to assist with this, many countries have turned to alternative energy. In this paper, Cascaded H-Bridge Multilevel inverter is intended using the pulse width modulation (PWM) Technique. The system is intended with a photovoltaic array, a lift converter to accelerate the output of the panel which uses Maximum electrical outlet Tracking (MPPT), and an H-bridge inverter for conversion from DC to AC. A Multilevel inverter using Cascaded H-Bridge may be a DC-AC inverter to cut back total harmonic distortion with different sinusoidal pulse width modulation (PWM) like phase disposition, phase opposition disposition, and space vector.

This paper presents a new dual switch control structure for an AC/DC non-inverting cascaded buck-boost power factor correction converter. The proposed converter operates at a discontinuous capacitor voltage mode providing an inherent high power factor and a zero voltage turn-off switching. Additionally, the proposed control structure enables for a non-distorted sinusoidal current for a wide range of output voltage levels. Unlike the conventional methods, a mode detector is not required and consequently there is no hard transition between buck and boost modes. Although both converter switches are controlled, only one feedback control loop is required to obtain the desired power flow at a unity power factor. The principle of operation, theoretical analysis, simulation, and experimental results of a 1.6 kW prototype grid connected converter are presented. The results confirmed the validity of the proposed system under various operating conditions.

Multilevel inverters (MLIs) are playing a major role in every sector of power industries, which is growing significantly over the years. Although multilevel inverters are highly applicable, they have some stern disadvantages that need to be dealt with. Some of the most common issues of MLIs include high usage of electric components, highly complex modulation techniques, presence of harmonics and so on. By keeping all these issues into mind, this paper investigates a single phase cross-switched MLI using abridged electric components. Furthermore, it has described a novel and simplified method of implementing sinusoidal pulse width modulation (SPWM) technique. The investigated MLI and the proposed modulation technique is validated by following both simulation and hardware approach. The simulation is performed using MATLAB Simulink software while the hardware prototype of the whole topology is built using TMS320F28335 digital signal processor (DSP) board.

This paper proposes and describes the design of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and significant suppression of the load harmonics contents are obtained at the inverter output. The harmonics contents of the proposed multilevel inverter can be reduced by half compared with the two-level inverter. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic distortion. The full-bridge power switches of the classical three-phase inverter operate at the line frequency of 50 Hz, while the auxiliary circuit switches operate at twice the line frequency. To validate the proposed topology, simulation and analysis have been performed. In addition, a prototype has been designed, implemented and tested. Selected simulation and experimental results have been provided.

—Different modulation techniques used to control multilevel converters can be classified based on the selected converter topology and optimization goals. Among all proposed modulation methods low switching frequency modulation techniques are very popular for multilevel converters yet non-real time low switching frequency methods cannot be applied to multilevel converters with unequal or varying DC values because these modulation techniques rely on look up tables and the size of look up tables will be huge in this case. This paper proposes a new modular multilevel converter (MMC) structure with unequal DC values. Some well-known low switching frequency modulation techniques and the commonly used PWM based methods are compared and using the new low switching frequency modulation technique called minimal total harmonic distortion (THD) modulation for MMC with unequal DC values is proposed. The PSCAD simulation results show that the new converter topology with unequal DC values has much lower THD compared to the typical MMC. Modulation algorithm is implemented in digital signal processor (DSP) and controller hardware in the loop (CHIL) implementation in RTDS verifies the real-time performance of the algorithm.

Most electronic and electrical appliances such as radio, televisions, computers, etc. uses DC supply internally. This is done by converting the source supply (single phase or three phase) into DC supply. The internal DC supply source makes the load compatible with its external power source. The presence of non-linear loads results into low Power Factor operation of the power system. Several techniques are adopted for Power Factor correction and harmonic reduction technique few of them have gained greater acceptance over the others. In this paper some of the bridgeless power factor correction boost converters are proposed which results in improved power factor and reduced harmonics content in input line currents as compared to conventional boost converter topology. In addition the bridgeless Power Factor correction boost converter is proving to have less conduction losses and has higher efficiency. Keywords-Total Harmonic Distortion (THD), Bridgeless Power Factor Correction (PFC) Boost Rectifier, Continuous Conduction Mode (CCM), Discontinuous Conduction Mode (DCM), Dual Boost PFC Rectifier, Fast-Recovery Diodes, Single Phase Rectifier

This paper proposed a simulation model of three different typologies of five-level inverter. The study investigated three topologies of multilevel inverter namely Flying Capacitor Multilevel Inverter (FCMLI), Diode Clamped Multilevel Inverter (DCMLI) and Cascaded H-bridge Multilevel inverter (CHMLI). These topologies were compared in terms of Total Harmonic Distortion (THD), switching loses and the number of power electronic components being utilized. The simulation result was conducted using MATLAB/SIMULINK. The findings showed that the PWM H-Bridge topology has the lowest total harmonic distortion (THD). In addition, the H-Bridge topology has the lowest switching losses and utilizes less power electronic components.

The paper presents power quality enhancement on low voltage of three phase grid caused by PV generator integration under variabel solar irradiance level on constant temperature and load. MPPT Fuzzy helps to generate duty cycle to control DC/DC boost converter of PV generators. This model was expected to improve power quality due to unbalance voltage and current, low voltage and current harmonics, and low input power factor. There were eigth scenarios PV generator connected to three phase grid using MPPT Fuzzy and compared with MPPT P and O. The research results that application of two methods on different irradiance and PV generator integration level produces unbalanced voltage value stable at 0%. At the same conditions, the use of MPPT Fuzzy results unbalanced current was greater than MPPT P and O. On solar irradiance level fixed, the greater number of PV generator connected to three-phase grid, then value of average voltage and current harmonics (THD) will increases. At the level of solar radiation increases, average grid voltage and current THD also have increased. The average grid voltage and current THD was reduced after using MPPT Fuzzy. The application of MPPT Fuzzy was able to enhance profile of grid voltage and current THD due to integration of a number of PV generator to three phase grid corresponding with IEEE Standard 519-1992. MPPT Fuzzy was capable to improve input power factor better than MPPT P and O.

This paper presents a single-phase active power filter for harmonic compensation which is consists of a series active power filter and a shunt passive filter. The active filter connected in series to a source acts as a harmonic isolator between the source and load whereas the shunt passive filter is connected in parallel with a load and suppresses the harmonic current produced by the load. The PSpice®, Matlab/Simulink® and MAX PLUS II® softwares are used for simulation and hardware implementation. From the simulation and experimental results it is confirmed that the filter topology is capable of compensating the load current and voltage harmonic distortion within the stipulated limits laid down by the international standard.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1600795

The DSP-based fuzzy logic controller for a battery charger has been investigated in this paper. The conventional battery charger experiences a highly distorted current harmonic waveform and low power factor. Thus, the proposed battery charger with a fuzzy logic controller to improve the line power quality and deliver maximum allowable output power to the battery. The fuzzy control algorithm is implemented with the Digital Signal Processor (DSP) to optimize a fuzzy rule-based system to produce the desired output. The TMS320C5x DSP is employed to supply the pulse width modulation (PWM) waveforms and to perform the fuzzy control feedback. The PWM waveforms are required to generate gating signals for the converters. The DSP-based fuzzy controller in turn provides control over the PWM pattern. The fuzzy controller continuously monitors the state of battery and controls the PWM accordingly. This simple and reliable DSP-based fuzzy control provides an easier implementation and optimum performance for the battery charger.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1182616

—The laboratory prototype of a frequency converter (FC) is analyzed using readily available Spartan-3E Field Programmable Gate Array (FPGA) kit and Personnel Computer (PC). The output frequency range has been varied over a wide range by implementing Sinusoidal pulse width modulation (SPWM) technique, in order to minimize the harmonics, using very high speed integrated circuit hardware descriptive language (VHDL). The experimental setup for the FC circuit has also been developed in order to verify the MATLAB/Simulink analysis of the circuit. The Total harmonic distortion (THD) analysis is obtained experimentally for un-modulated and modulated frequency converter. It has been demonstrated that for step-up mode of operation of modulated frequency converter, minimum voltage THD is 6.6 % and current THD is 2.1 %. While during step-down mode of operation, 1.8% is minimum voltage THD and 1.1% is minimum current THD respectively. The THD in voltage and current has been significantly minimized by implementing FC with SPWM technique.

This paper highlights the problems associated with
single pulse width modulation, the most important being high
harmonic content in output voltage. A comparative study with
Sinusoidal Pulse Width Modulation Technique is done
highlighting the reduction in Total Harmonic Distortion of the
output voltage waveform.

Conventional light sources are less efficient as compared to the light emitting diode and compact fluorescent lamps. Conventional incandescent filament lamps are resistive and therefore do not depend on power quality parameters. In the electric power system, nonlinear loads are increasing rapidly and the high content of harmonic due to the nonlinear loads cannot be neglected. Harmonic generation from the light emitting diode and the compact fluorescent lamp is one of the main problems for power quality. In this study, the light efficiency and electrical characteristics of the light emitting diode lamps and compact fluorescent lamps are evaluated under various voltage harmonic levels. The results show that light emitting diode, produces more harmonics as compared to the compact fluorescent lamps, with the increase of the voltage harmonic distortion from 0.7% to 3.52% in the light emitting diode, current harmonic increased from 140% to 192%. The results also show that increase in voltage harmonic distortion just not only increase current harmonics distortion but also affect the light wavelength of the lamp.

This paper proposes a new fuzzy logic controller for seven-level hybrid cascaded H-bridge inverter. The inverter is used for on-grid application of PV a system. Here a Sinusoidal pulse width-modulation (SPWM) technique is applied for obtaining carrier signals. Multi-Level Inverter technology have been developed in the area of high-power medium-voltage energy scheme. It is because of their advantages such as devices of high dv/dt rating, higher switching frequency, unlimited power processing, shape of output waveform and desired level of output voltage, current and frequency adjustment. This topology can be used there by enabling the scheme to reduce the Total Harmonic Distortion (THD) for high voltage applications. The Maximum Power Point tracking algorithm is also used for extracting maximum power from the PV array connected to each DC link voltage level. The Maximum Power Point tracking algorithm is solved by Perturb and Observer method. It has high performance with low Total Harmonic Distortion and reduced by this control strategy.

Power quality is a pressing concern and of the utmost importance for advanced and high-tech equipment in particular, whose performance relies heavily on the supply’s quality. Power quality issues like voltage sags/swells, harmonics, interruptions, etc. are defined as any deviations in current, voltage, or frequency that result in end-use equipment damage or failure. Sensitive loads like medical equipment in hospitals and health clinics, schools, prisons, etc. malfunction for the outages and interruptions, thereby causing substantial economic losses. For enhancing power quality, custom power devices (CPDs) are recommended, among which the Dynamic Voltage Restorer (DVR) is considered as the best and cost-effective solution. DVR is a power electronic-based solution to mitigate and compensate voltage sags. This paper provides a thorough discussion and comprehensive review of DVR topologies based on operations, power converters, control methods, and applications. The review compares the ...

Solar PV system development and integration with existing grid is very fast in recent years all over the world, as they require limited maintenance, pollution free and simple structure. When observing the factors affecting the performance of the grid connected solar photovoltaic system, the inverter output voltage with harmonics add with the harmonics generated due to the non-linear loads, retain a bigger challenge to maintain power quality in the grid. To maintain grid power quality, better inverter control technique should be developed. This paper presents the two control techniques for grid-tied inverters. This study developed the hysteresis controller for the inverter. Hysteresis controller used in this work two way (i) Voltage control mode (ii) Current control mode. Matlab/Simulink model is developed for the proposed system. Further the study presents the comparative evaluation of the performance of both control techniques based on the percentage of total harmonic distortion (THD) with the limits specified by the standards such as IEEE 1547 and IEC 61727 and IEEE Std 519-2014.

An AC-DC flyback converter for outdoor LED lighting is proposed. In the proposed converter is designed to be operated in the discontinuous-conduction mode (DCM) to achieve a high power factor. A DC-DC flyback module is designed to provide input-output electrical isolation. This improves safety. In addition to this, a low-voltage-rating capacitor can be used as the DC-bus. PSIM based simulations are carried out. This paper addresses a novel approach for designing and modeling of the isolated flyback converter. A detailed analysis and simulation are conferred for flyback converter in discontinuous conduction mode (DCM).

This paper presents an implementation of single phase voltage source inverter (VSI) control algorithm for grid connected photovoltaic (PV) system. The maximum power point tracking (MPPT) is capable of extracting maximum power from PV array connected to DC link voltage level. The MPPT algorithm is solved by incremental conductance method (INC). Sinusoidal pulse width modulation (SPWM) uses a simple mapping to generate gate signals for the inverter. A new digital proportional resonant (PR) current control algorithm is used to remain the current injected into the grid sinusoidal and to achieve high dynamic performance with low total harmonic distortion (THD). The validity of the system is verified through MATLAB/ Simulink and results are compared with proportional integral (PI) algorithm for PV system in terms of THD.

Multilevel inverters are emerging as the new breed of power converter options for high power applications. They typically synthesis the staircase voltage waveform (from several dc sources) which reduced harmonic content. This paper presents a simple selective harmonic elimination (SHE) modulation for single-phase cascaded H-bridge (CHB) multilevel inverter. The optimum switching angle of the transcendental equations describing the fundamental and harmonic components is solved by means of the Newton-Raphson (NR) method. The proposed SHE scheme is performed through simulation using MATLAB/Simulink. This simulation results are then verified through experiment using Altera DE0-Nano field-programmable gate array (FPGA). The proposed SHE is efficient in eliminating the lowestorder harmonics and producing a higher quality output waveform with a better harmonic profile.

In this paper, voltage sag compensation of point of common coupling (PCC) using a new structure of fault current limiter (FCL) is proposed. The proposed structure prevents voltage sag and phase-angle jump of the substation PCC after fault occurrence. This structure has a simple control method. Using the semiconductor switch (insulated-gate bipolar transistor or gate turnoff thyristor at dc current rout leads to fast operation of the proposed FCL and, consequently, dc reactor value is reduced. On the other hand, the ...

Modular multilevel converter (MMC) has become a promising technology Handling of Electric vehicles (EV) power source by using different techniques and algorithm. Where the battery cells are series connected to enhance the output voltage. In this topology, individual batteries are connected together and became a dc link of the converter subsystem, to allowing the highest flexibility for the discharge and recharge by estimating the State of charge. The battery power has kept in balance by sorting algorithm and the controlling the submodules by PS-PWM techniques. Interactive power management at EVs will make effective utilization of battery power and switching of semiconductor can operate motor into regenerative mode. Simulation study has been done in MATLAB/SIMULINK platform and it is observed the output voltage, THD % values and State-of-Charge (SOC) of batteries are well maintained.