Harmonic Reduction,

To foster the widespread adoption of solar power, especially that produced by photovoltaic (PV) systems, we must move beyond the mere utilization of renewable energy sources. Prioritizing cost-effective approaches through innovative grid integration is essential. This strategic transformation significantly contributes to the global expansion of electrical energy production. One pioneering approach involves the implementation of inverters operating at high frequencies to efficiently filter and eliminate undesirable current harmonics, thus enhancing system performance. This innovative technique relies on the generation of rapid complementary digital pulse width modulation (PWM) signals, complete with built-in dead time, to manage a half-bridge inverter with a single phase. The paper recommends employing the IR2110 driver, an often-used component for MOSFET switch management, to execute this strategy. The entire system is controlled by high-frequency PWM signals, meticulously programmed for precision, generated by a microcontroller driver board. With its adaptability to various renewable energy conversion devices, this methodology extends its utility beyond solar energy. Practical tests have confirmed the efficacy of this strategy. Future research in this field should scrutinize the effect of PWM on system stability and harmonic distortion, explore advanced modulation methods, align PWM approaches with upcoming power electronics technologies, and work towards improving system efficiency.

This study aims to enhance power quality in grid-connected photovoltaic (PV) systems by introducing an intelligent fuzzy logic-based adaptive control strategy for dynamic PLL switching in a DVR-supported configuration. A 100-kW grid-tied PV system is modeled with a digital phase-locked loop (DPLL), a conventional synchronous reference frame PLL (CTPLL), and a dynamic voltage restorer (DVR). A Mamdani-type fuzzy inference system (FIS) performs real-time PLL selection based on phase-wise real-time fault monitoring. The system was tested under symmetrical and asymmetrical 20% sag and swell conditions, evaluating voltage stability at both PCC and load, total harmonic distortion (THD), recovery time, and synchronization accuracy. Results show that the proposed method reduces unnecessary DVR voltage injection from ~50 V to ~5-6 V under healthy conditions, maintains a near-unity power factor (< 0.95), and achieves up to 15% THD reduction in inverter current and PCC currents compared to DPLL-only operation. Recovery times improved by up to 25%, with stable synchronization maintained in all fault cases. The integration of adaptive PLL switching and targeted DVR activation offers a novel, hardware-efficient approach to harmonic suppression, voltage stabilization, and fault resilience in medium-scale PV systems.

The flexibility and linearity of renewable energy generation techniques motivate the efforts to find high-performance circuitries capable of integrating the generation stations of renewable energy with the utility grid. As a result of its potential for power modules exploited in new generations of semiconductor switching devices, the voltage source inverter (VSI) has become widespread in the applications of renewable energy systems. In this paper, a new configuration of multilevel VSI is introduced. It is constructed of a unidirectional voltage supply having 15-nonzero levels and feeding a single-phase VSI equipped with an extra-freewheeling circuit. The output voltage of this configuration has 31 different voltage levels following a sinusoidal path. The unidirectional voltage supply is built of eight solid-state switching devices and four binary weighted DC voltage sources, which are realized by using appropriate solar panels. The simulation results of the introduced configuration have revealed almost sinusoidal output voltage and current for both inductive and resistive appliances. The number of employed switching devices is largely reduced compared to a conventional multilevel VSI. No harmonic reduction circuit or traditional pulse width modulation technique is employed in the current design. This system is designed and tested on PSpice.

Power quality is a measure of ideal power supply system. There are many voltage related power quality issues in the industries like impulse, voltage sag and swell, over and under voltage, flickers, harmonics, voltage interruption etc. but the harmonics is a very commonly and most affected issue in industry , So we focus on the harmonics and brief discussion about other issue. There are many nonlinear devices which are using in industries like air compressors, blowers, VFD operated motors and various air handling units which inject harmonics in to the line, which create power quality problem. Filter is used for reduce harmonics. Many types of filters are available in market like active filter, passive filter, low pass filter, high pass filter, single tuned filter, hybrid filter etc. We use hybrid filter for reduce the harmonics because it reduce the harmonics nearer to zero which is advance than any other filter. Matlab use for hybrid filter simulation and results shows how this filter reduces the harmonics.

A Three phase Shunt Active Power Filter (SAPF) is use to compensate the harmonic produce by the nonlinear load. The very important part of the Shunt Active Power Filter is generating the gate signal for the voltage source inverter (VSI). In this work Hysteresis current control techniques is use. The reference harmonic component extraction is based on the instantaneous active and reactive power theory (P-Q theory) in time domain. The active power filter is able to improve the Total Harmonic Distortion (THD) for the distorted line current caused by uncontrolled rectifier (nonlinear load) and meet IEEE 519 standard recommendations on harmonic level. Matlab /

A Three phase Shunt Active Power Filter (SAPF) is use to compensate the harmonic produce by the nonlinear load. The very important part of the Shunt Active Power Filter is generating the gate signal for the voltage source inverter (VSI). In this work Hysteresis current control techniques is use. The reference harmonic component extraction is based on the instantaneous active and reactive power theory (P-Q theory) in time domain. The active power filter is able to improve the Total Harmonic Distortion (THD) for the distorted line current caused by uncontrolled rectifier (nonlinear load) and meet IEEE 519 standard recommendations on harmonic level. Matlab / Simulink is used as a simulation tool for the research.

This is a well-known fact that during a transformerrectifier combination undesirable harmonic line currents may be generated. The rectification of alternating current power to direct current power itself may produce undesirable current harmonics. The non-linear loads cause the severe current harmonics that can not be tolerated. These harmonic currents can cause either a shutdown of the device or the unacceptable powering of the devices. The non-isolated multi-pulse converters and the Multi-pulse converters in general can be applied to achieve the clean power which is of major priority in higher power rating applications. Generally, by increasing the number of pulses in a multi-pulse converter THD (total harmonic distortion) can be reduced up to the allowable limits. Thepresentwork istoanalyses the differentmulti-pulse AC toDC (18-pulse, 24-pulse, 36-pulse, and 48-pules) converters insolvingthe harmonic problem in athree-phase converter system. The effect of increasing the number of pulses on the performance of ac-dc converters is analyzed. THD is the major factor considered for the performance comparison of various converters.

In this paper, a 4-H-bridge STATCOM (4-HB STATCOM) is introduced. Four H-bridges are cascaded to build the proposed STATCOM. Cascading the H-bridges makes it possible to operate the devised STATCOM on high voltage levels with less voltage harmonic association. The proposed STATCOM is equipped with an adaptive current controller and a voltage balancing technique for its DC capacitor voltages. The adopted controlling strategy makes the STATCOM respond continuously and linearly to current demand in both inductive and capacitive operational modes without noticeable association of harmonics. The DC capacitor of each H-bridge is shunted by a second harmonic filter to stabilize its voltage. The proposed STATCOM does not require initial charging of its DC capacitors because it is provided with a utilized technique for charging them rapidly by disabling the STATCOM carrier for a certain period sufficient to build up the required level of DC voltages. In this work, the proposed STATCOM is designed to operate on 11 kV AC voltage as a continuously and linearly controlled compensating susceptance. It can deservingly be employed in load balancing systems for achieving big amount of energy savings in power generation and big reduction in transmission losses.

In this paper, a load balancing system is designed to balance the secondary phase currents of 11 kV/380 V, 50 Hz, 100 kVA power transformer in a three phase 4-wire, distribution network. The load balancing system is built of six identical modified static synchronous compensators (M-STATCOMs). Each M-STATCOM is constructed of a voltage source converter-based H-bridge controlled in capacitive and inductive modes as a linear compensating susceptance. The M-STATCOM current is controlled by varying its angle such that it exchanges pure reactive current with the utility grid. Three identical M-STATCOMs are connected in delta-form to balance the active phase currents of the power transformer, whereas the other three identical M-STATCOMs are connected in star-form to compensate for reactive currents. The M-STATCOMs in the delta-connected compensator are driven by 380 V line-to-line voltages, whilst, those connected in starform are driven by 220 V phase voltages. The results of the 220 V and 380 V M-STATCOMs have exhibited linear and continuous control in capacitive and inductive regions of operation without steady-state harmonics. The proposed load balancing system has offered high flexibility during treating moderate and severe load unbalance conditions. It can involve any load unbalance within the power transformer current rating and even unbalance cases beyond the power transformer current rating.

Shunt Active power filters (SAPF) technology has emerged nowadays as a very suitable option for power quality improvement in electrical power systems control. This paper presents the simulation study of a fuzzy logic hysteresis band current controlled, three-phase SAPF to enhance power quality by harmonic elimination, power-factor correction, reactive power compensation and balancing of nonlinear loads. The advantage of fuzzy control is that it is based on a linguistic description and does not require a mathematical model of the system. Further, in this paper, the hysteresis based current control method is implemented for pulse width-modulation (PWM) switching signals. Results obtained by simulations with Matlab/Simulink show that dynamic behavior of the fuzzy controller is more effective than the conventional proportionalintegral (PI) controller method on compensating reactive power and harmonic currents of the load. It is found to be more robust to changes in load and other system parameters compared to the conventional PI controller under steady state and transient conditions.

Abstruct-New harmonic elimination pulse-width modulation (HEPWM) techniques of real time inverter control for induction motor drives will be presented in the paper. These techniques can be implemented on-line in real tine, without resorting to any conventional off-line numerical techniques nor extensive look-up tables (LUTs). It will be shown that the developed HEPWM techniques can be implemented by calculating switching angles using simple algebraic equations and selecting switching states. Simulation and experimental results derived from test induction motor drives will be presented to confirm and demonstrate the features of the techniques.

The article presents a seven-level reduced switch asymmetrical multilevel inverter with two different methods of pulse width modulation (PWM) techniques. Phase disposition (PD) PWM and hybrid variable-frequency phase disposition PWM (HVFPD-PWM) are the two different PWM methods for making the quality of output voltage waveform. In the first method, the unipolar sine reference with triangular carriers is used. In the second method, the hybrid unipolar reference (sinusoidal with trapezoidal) is proposed with variable frequency carriers to generate the switching pulses for asymmetric multilevel inverter (MLI). The main objective of this proposed method is to reduce the total harmonic distortion in the output voltage waveforms. A comprehensive comparison of the proposed HVFPD-PWM and the conventional PD-PWM with asymmetrical seven-level inverter is presented to show the enriched performances of the proposed method. The performance and viability of the suggested PWM are evaluated through simulation and experimental results using an asymmetrical seven-level inverter. The total harmonic distortion for the proposed PWM method (16.95%) is significantly reduced as compared with the conventional PWM method (18.01%) at the modulation index of one.

In the research area of high voltage with high power energy control, multilevel inverter (MLI) technology is constantly evolving. MLI finds its uses in renewable energy, improving power quality using FACTS devices, HVDC, electric vehicles, etc. Various topologies of MLI along with different modulation schemes have been developed. In this paper, the topic of interest is the recently developed Cross T-Type (CT-Type) MLI. Here, various multi-carrier pulse width modulation (MCPWM) techniques, viz. phase disposition, phase opposite disposition and alternate phase opposition disposition, third harmonic injection (THI)-based PWM and nearest level control (NLC), are applied and their effectiveness are studied in case of CT-Type MLI. The output waveform for each of these modulation techniques is compared in light of parameters like total harmonic distortion (THD) and peak voltage. The CT-Type MLI shows far promising performance in terms of THD for NLC modulation technique, but in terms of output voltage, level-shifted techniques perform better.

In the research area of high voltage with high power energy control, multilevel inverter (MLI) technology is constantly evolving. MLI finds its uses in renewable energy, improving power quality using FACTS devices, HVDC, electric vehicles, etc. Various topologies of MLI along with different modulation schemes have been developed. In this paper, the topic of interest is the recently developed Cross T-Type (CT-Type) MLI. Here, various multi-carrier pulse width modulation (MCPWM) techniques, viz. phase disposition, phase opposite disposition and alternate phase opposition disposition, third harmonic injection (THI)-based PWM and nearest level control (NLC), are applied and their effectiveness are studied in case of CT-Type MLI. The output waveform for each of these modulation techniques is compared in light of parameters like total harmonic distortion (THD) and peak voltage. The CT-Type MLI shows far promising performance in terms of THD for NLC modulation technique, but in terms of ou...

In AC power grids for harmonic emission reduction and reactive power compensation, activity filters have become very common. The network with non-linear loads such as power converters is equipped with an active power filter for optimizing THD. Shunt type or series type. It also enhances voltage control and unbalance in flicks. For most active control filters, the instantaneous power principle also known as p-q theory is used. This paper explains Shunt active power filter for a 3-phase wire AC network. The proposed shunt active power filter uses principle of instantaneous reactive rower to remove harmonics from source streams. On the Matlab/Simulink method, the simulation results are shown.

This paper proposes a new adaptive control technique for shunt active power filter (SAPF) by applying the interval type-2 fuzzy controller (IT2FC) in the DC voltage outer loop. This adaptive method achieved the main control objectives and compensated the active filter parameters uncertainties besides the unbalanced loads compensation without neutral wire. The interval type-2 fuzzy controller (IT2FC) offers flexibility and compensates the uncertainties within large ranges due to its footprint of uncertainty. The IT2 fuzzy controller proved flexibility and faster DC voltage transient response than the PI and type-1 fuzzy controllers due to its type-2 membership functions which describe uncertainties in contrast to the type -1 membership functions which describe vagueness. Simulation results proved that the IT2 fuzzy controller has faster response and robust performance against parameters variations and unbalanced loads compared to PI and type -1 fuzzy controllers

In recent years, the use of multilevel inverter has become popular due to its many advantages. Due to the popularity of multilevel inverters in industries and in applications that require a wide range of voltages, there have been many challenges to achieve high-quality voltage. Many pieces of research have been done to solve the problem of annoying harmonics in multilevel inverters. In this study, pulse width modulation (PWM) has been proposed as a switching method. Using the Selective Harmonic Elimination (SHE) technique, the inverter switching can be carried out in low frequency, and also, this method can reduce the annoying harmonics significantly. However, in the lower modulation index, eliminating such harmonics is challenging, resulting in a considerable increase in output voltage distortion. This study suggests a way to solve the problem. In this research, eliminating selected harmonics in a multilevel inverter with variable DC links is proposed. The DC-link variable method i...

The increased use of non-linear loads results in more harmonics content in the source current. Shunt active power filters are used for correction of distorted source current by injecting a compensating current in parallel to the load current. The injected current will shape the supply current to a sinusoidal. In this paper an improved performance of shunt active power filter is achieved by using sliding mode controller for generation of gate pulses of voltage source inverter. The implemented control technique has been evaluated and compared with hysteresis current control. The performance parameters used for evaluating the shunt active power filter are total harmonic distortion, power factor and harmonics compensation ratio. The simulation results show excellent performance of active power filter in terms of harmonics mitigation and dynamic response. Experimental tests are also performed using NI DAQ card in Labview environment to validate the simulation results. Both the simulation and experimental results prove good performance of sliding mode control for accurate injection of reference current.

In this paper, new types of pulse width modulation techniques are proposed to improve the performance of multi-level inverter. The effort is taken for this performance improvement without making any changes in the material of the multi-level inverter. Multi-level inverter performance depends on pulse width modulation technique adopted in it. The proposed techniques have the characteristics of exhibiting less total harmonic distortion. The output voltage is also improved. In this paper, these proposed techniques are applied to multi-level inverter and the performances are evaluated. It is simulated in MATLAB/Simulink and the results are obtained. The results are compared with the conventional method to look into its validity.

In AC power grids for harmonic emission reduction and reactive power compensation, activity filters have become very common. The network with non-linear loads such as power converters is equipped with an active power filter for optimizing THD. Shunt type or series type. It also enhances voltage control and unbalance in flicks. For most active control filters, the instantaneous power principle also known as p-q theory is used. This paper explains Shunt active power filter for a 3-phase wire AC network. The proposed shunt active power filter uses principle of instantaneous reactive rower to remove harmonics from source streams. On the Matlab/Simulink method, the simulation results are shown.

The growing interest in power quality has led to variety of devices are designed for mitigating power disturbances such as harmonics caused due to different problems. By minimizing Total Harmonic Distortion (THD) the Harmonic Pollution will be reduced and Power Quality will be increased. Different types of load draw non-sinusoidal current from mains. This non-linear load appears to be the main source of harmonic distortion. Thus the main aim of shunt active filter that comprises of PI Controller, filter hysteresis current control loop and DC link capacitor is used to mitigate Total Harmonic Distortion (THD). Thus, in order to overcome these harmonic problems it is verified using MATLAB/SIMULINK package. Active filters are used to eliminate current harmonics near non – linear loads. Here the two methods are compared Instantaneous reactive power theory and sinusoidal theory. The results of both the methods are shown on the basis of the MATLAB/SIMULINK. Thus, following thesis gives the overview of the harmonic problems and its impact on power system and how shunt active filters mitigate these harmonics using MATLAB.

When using non linear loads, affects the quality of supply power ,which leads to a number of issues like harmonics, voltage sag, voltage swell, flicker, voltage imbalance etc. these issues affects the performance and the lifetime of the utilities. In order to overcome issues arises due to nonlinear loads power filters were developed. This work proposed an active filter which is controlled by PI controller to reduce the THD (total harmonic distortion). Here we compared the results of active filter results, without controller and with PI controller.

The shunt active filter has proved to be a useful device to harmonic currents and to compensate reactive power for linear/nonlinear loads. This paper presents a simulation of Sliding mode control of three-phase shunt active power filter to improve the power quality using Matlab Power system blockset. After compensation, the source current is sinusoidal under ideal and non-ideal mains voltage

In variable speed drive (VSD), it is desirable to reduce the harmonic effects, which causes current distortion and torque pulsation, besides, the harmonic power losses is an additional power losses that is introduced in the motor due to the presence of harmonic voltages.
However, the problem of the high total harmonic current distortion (THD) still exists specially at low and medium speeds by using sub-optimal pulse width modulation (PWM) strategy. In the past to generate optimized PWM, is done by defining a general PWM in terms of a set of switching angles. Which result in a set of nonlinear equations in terms of the unknown switching angles. These equations are nonlinear as well as transcendental in nature. There is no efficient method that can be applied to solve such equations. The practical method of solving these equations is a trial and error process. Taking all the factors into account, a numerical technique can be applied to solve these set of nonlinear equations, but with some limitations.
To overcome these limitations, Genetic algorithms (GAs) serves to search for optimal switching angles setting. In addition, the (THD) will be reduced, this lead to obtain the optimal PWM waveform and to simplify the practical implementation, and then improving the performance of the system output.
GAs were employed as a search and optimization engine. Normally the tuning of the switching angles is a trail and error problem.
In this paper, GAs provides a much simpler approach to off-line tuning of PWM switching angles than the rather complicated non-genetic optimization algorithms.
Keywords: Optimization, Genetic algorithm, PWM.

A simple but powerful design method based on realcoded
Genetic algorithms (GAs) to solve the minimization of the
Total Harmonic Distortion (THD) criterion is obtained. GAs
provides a much simpler approach to off-line tuning of Pulse
width Modulation (PWM) switching angles than the rather
complicated non-genetic optimization algorithms. Genetic
algorithms are exploratory search and optimization procedures
that were devised on the principles of natural evolution and
population genetics.

Modern industrial equipments are more sensitive to these power quality problems than before and need higher quality of electrical power. Power electronic based power processing offers higher efficiency, compact size and better controllability. But on the flip side, due to switching actions, these systems behave as non-linear loads. This creates power quality problems such as voltages Sag/Swell, flickers; harmonics, asymmetric of voltage have become increasingly serious. At the same time, modern industrial equipments are more sensitive to these power quality problems than before and need higher quality of electrical power. This paper mainly deals with shunt active power filter which has been widely used for harmonic elimination. Active power filter which has been used here monitors the load current constantly and continuously adapt to the changes in load harmonics. The performance of three phase shunt active power filter using three phase two phase transformation with PI and Hysteresis current controller is explained in this paper.

This article proposes a new approach to reduce harmonics generated by a three-phase diode rectifier. The proposed approach uses the input filters, six controllable switches, high-frequency isolation transformer, and the three-phase diode rectifier. The switching of the controllable switches is modulated by a novel pulse-width modulation (PWM) implemented in an XC4006 field programmable gate array (FPGA). This approach realizes sinusoidal input current waveforms with low electromagnetic interference and arbitrary output voltage. The output voltage can be controlled by variation of the modulation index in the range (0 ≤ M ≤ 0.98). The experimental results to compare performance between with and without the proposed approach are carried out to confirm its feasibility.

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