Genetic Algorithm Based 7-Level Step-Up Inverter with Reduced Harmonics and Switching Devices

This paper presents a unique voltage-raising topology for a single-phase seven-level inverter with triple output voltage gain using single input source and two switched capacitors.The output voltage has been boosted up to three times the value of input voltage by configuring the switched capacitors in series and parallel combinations which eliminates the use of additional step-up converters and transformers.The selective harmonic elimination(SHE)approach is used to remove the lower-order harmonics.The optimal switching angles for SHE is determined using the genetic algorithm.These switching angles are com-bined with a level-shifted pulse width modulation(PWM)technique for pulse generation,resulting in reduced total harmonic distortion(THD).A detailed com-parison has been made against other relevant seven-level inverter topologies in terms of the number of switches,drivers,diodes,capacitors,and boosting facil-ities to emphasize the benefits of the proposed model.The proposed topology is simulated using MATLAB/SIMULINK and an experimental prototype has been developed to validate the results.The Digital Signal Processing(DSP)TMS320F2812 board is used to generate the switching pulses for the proposed technique and the experimental results concur with the simulated model outputs.

Study and Design of a DC/AC Energy Converter for PV System Connected to the Grid Using Harmonic Selected Eliminated (HSE) Approach

Nowadays, distributing network-connected photovoltaic (PV) systems are expanded by merging a PV system and a Direct Current (DC)/Alternating Current (AC) energy converter. DC/AC conversion of PV energy is in great demand for AC applications. The supply of electrical machines and transfer energy to the distribution network is a typical case. In this work, we study and design a DC/AC energy converter using harmonic selective eliminated (HSE) method. To this end, we have combined two power stages connected in derivation. Each power stage is constituted of transistors and transformers. The connection by switching of the two rectangular waves, delivered by each of the stages, makes it possible to create a quasi-sinusoidal output voltage of the inverter. Mathematical equations based on the current-voltage characteristics of the inverter have been developed. The simulation model was validated using experimental data from a 25.2 kWp grid-coupled (PV) system, connected to Gridfit type inverters. The data were exported and implemented in programming software. A good agreement was observed and this shows all the robustness and the technical performances of the energy converter device. It emerges from this analysis that the inverter output voltage and the phase angle thus simulated are very important to control in order to orientate the transfer of the power flow from the continuous cell to cell to the alternating part. Simulated and field-testing results also show that increases in the value of the modulation factor (m) for low power output are highly significant. This study is an important tool for DC/AC inverter designers during initial planning stages. A short presentation of the design model of the inverter has been proposed in this article.

Double-phase-shift filtering method for harmonic elimination based on AR2U-Net

The double-phase-shift filtering method,which is based on the traditional purephase-shift filtering method,is a novel approach to harmonic elimination that can be applied to more complicated signals such as white noise and slip-sweep.Nonetheless,any type of phase-shift filtering method necessitates a relationship between the frequency of fundamental sweep and time,which may cost necessitate an enormous amount of human and physical resources to achieve inaccurate results with low efficiency.This paper combines deep learning with harmonic elimination to produce a double-phase-shift filtering method based on AR2UNet,a type of U-Net with attention gates structure and recurrent residual blocks for improving accuracy and function while simplifying computational complexity.The input of the AR2UNet structure in this paper is seismic data of slip-sweep signals in vibroseis,and the output is signal frequency variation with the time of the fundamental waves,which are required to eliminate the harmonic waves and adjacent signals using a double-phase-shift method to obtain the fundamental sweep.The training sets and test sets are formed by forward models,and a Log-Cosh loss function is used to monitor the process,during which the results of AR2U-Net and traditional U-Net are compared to demonstrate the eminent function of AR2UNet.Following that,the outcomes’Log-Cosh loss functions and accuracy are also compared to validate the conclusion.AR2U-Net,when applied to raw data and combined with the doublephase-shift method,tends to polish the filtering effects and is worth promoting.

A type of inverter power supply based on harmonic elimination PWM control

In order to output sine wave with small degree of distortion and improve stability,a type of inverter power supply is designed based on harmonic elimination pulse-width modulation(PWM)control.The rectifier and filter are added to input circuit of the inverter.Single-phrase full-bridge inverter performs the function of converting direct current into alternating current(DC/AC).In the control circuit,single chip micyoco(SCM)AT89C2051 is used for main control chip to accomplish the hardware design of the control system.A given value of output frequency of the inverter is input in the way of coding.According to the output frequency code which is read,SCM AT89C2051 defined harmonic elimination PWM control data which will be selected.Through internal timing control,the switches are switched under this provision of PWM control data.Then the driving signals of the switches in the inverter are output from I/O of SCM AT89C2051 to realize harmonic elimination PWM control.The results show that adding Newton homotopic algorithm of harmonic elimination PWM control to corresponding software of the control system can make the quality of output voltage of the inverter higher and it will have broad application prospects.

Selective harmonic elimination method for wide range of modulation indexes in multilevel inverters using ICA

Selective harmonic elimination(SHE) in multilevel inverters is an intricate optimization problem that involves a set of nonlinear transcendental equations which have multiple local minima. A new advanced objective function with proper weighting is proposed and also its efficiency is compared with the objective function which is more similar to the proposed one. To enhance the ability of the SHE in eliminating high number of selected harmonics, at each level of the output voltage, one slot is created. The SHE problem is solved by imperialist competitive algorithm(ICA). The conventional SHE methods cannot eliminate the selected harmonics and satisfy the fundamental component in some ranges of modulation indexes. So, to surmount the SHE defect, a DC-DC converter is applied. Theoretical results are substantiated by simulations and experimental results for a 9-level multilevel inverter. The obtained results illustrate that the proposed method successfully minimizes a large number of identified harmonics which consequences very low total harmonic distortion of output voltage.

Harmonic Minimization in Seven Level Cascaded Multilevel Inverter Using Selective Harmonic Elimination PWM Techniques

This paper concentrates on enhancing the productivity of the multilevel inverter and nature of yield voltage waveform. Seven level lessened switches topology has been actualized with just seven switches. Essential Switching plan and Selective Harmonics Elimination were executed to diminish the Total Harmonics Distortion (THD) esteem. Selective Harmonics Elimination Stepped Waveform (SHESW) strategy is executed to dispense with the lower order harmonics. Fundamental switching plan is utilized to control the switches in the inverter. The proposed topology is reasonable for any number of levels. The harmonic lessening is accomplished by selecting fitting switching angles. It indicates would like to decrease starting expense and unpredictability consequently it is able for modern applications. In this paper, third and fifth level harmonics have been disposed of. Simulation work is done utilizing the MATLAB/Simulink programming results have been displayed to accept the hypothesis.

Harmonic Minimization in Seven-Level Cascaded Multilevel Inverter Using Evolutionary Algorithm

Inverters are power electronic devices that change over DC to sinusoidal AC quantity. Be that as it may, in down to earth, these devices produce non-sinusoidal yield which contains harmonics, so as to blend a close sinusoidal component and to lessen the harmonic distortion multilevel inverters developed. Mathematical methods, which were developed, are derivative based and need initial considerations. To overcome this, evolutionary algorithms, which are derivative free and accurate, were developed for obtaining multi levels of output voltage. The proposed work uses two evolutionary algorithms, namely, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) algorithm. These algorithms are used to generate the switching angles by satisfying the non linear transcendental equations that govern the low order harmonic components. A seven level cascaded full bridge inverter is designed using MATLAB/Simulink and the results validate the results for switching angles. The Total Harmonic Distortion (THD) value obtained for GA and PSO is 11.81% and 10.84% respectively. The solution obtained from GA algorithm was implemented in hardware using dsPIC controller to validate the simulation results. The THD value obtained for cascaded seven-level multilevel inverter in the hardware prototype is 25.9%.

An Intelligent Intrusion Detection System in Smart Grid Using PRNN Classifier

Typically,smart grid systems enhance the ability of conventional power system networks as it is vulnerable to several kinds of attacks.These vulnerabil-ities might cause the attackers or intruders to collapse the entire network system thus breaching the confidentiality and integrity of smart grid systems.Thus,for this purpose,Intrusion detection system(IDS)plays a pivotal part in offering a reliable and secured range of services in the smart grid framework.Several exist-ing approaches are there to detect the intrusions in smart grid framework,however they are utilizing an old dataset to detect anomaly thus resulting in reduced rate of detection accuracy in real-time and huge data sources.So as to overcome these limitations,the proposed technique is presented which employs both real-time raw data from the smart grid network and KDD99 dataset thus detecting anoma-lies in the smart grid network.In the grid side data acquisition,the power trans-mitted to the grid is checked and enhanced in terms of power quality by eradicating distortion in transmission lines.In this approach,power quality in the smart grid network is enhanced by rectifying the fault using a FACT device termed UPQC(Unified Power Quality Controller)and thereby storing the data in cloud storage.The data from smart grid cloud storage and KDD99 are pre-pro-cessed and are optimized using Improved Aquila Swarm Optimization(IASO)to extract optimal features.The probabilistic Recurrent Neural Network(PRNN)classifier is then employed for the prediction and classification of intrusions.At last,the performance is estimated and the outcomes are projected in terms of grid voltage,grid current,Total Harmonic Distortion(THD),voltage sag/swell,accu-racy,precision,recall,F-score,false acceptance rate(FAR),and detection rate of the classifier.The analysis is compared with existing techniques to validate the proposed model efficiency.

Analysis on the Application of Reactive Power Compensation Technology in Electrical Automation

This paper introduces in detail the reactive power compensation technology and its characteristics, to reduce the loss of reactive power compensation technology 1N power distribution system and the electrical automation, improve the utilization rate, and realize the control of the voltage amplitude in the system network, voltage stability of power distribution system, has carried on the system analysis to reduce failure of the harmonic current to the power supply system and other functions. And the paper in-depth study on the application of reactive power compensation technology in electrical automation from the reactive compensation technology, substation and distribution line reactive power compensation, power users of reactive power compensation and other aspects.

Grid-Connected Control Strategy of VSG under Complex Grid Voltage Conditions

Under complex grid conditions,the grid voltage usually has an imbalance,low order harmonics,and a small of DC bias.When the grid voltage contains low order harmonics and a small amount of DC bias component,the inverter’s output current cannot meet the grid connection requirements,and there is a three-phase current imbalance in the control strategy of common VSG under unbalanced voltage.A theoretical analysis of non-ideal power grids is carried out,and a VSG control strategy under complex operating conditions is proposed.Firstly,the third-order generalized integrator(TOGI)is used to eliminate the influence of the DC component of grid voltage.An improved delay signal cancellation(DSC)method is proposed to control the balance current and power fluctuation under unbalanced voltage based on the method of common VSG positive and negative sequence separation,It also eliminates the harmonic of command current.Then,the improved quasi proportional resonant controller(QPR)cascaded PI is used to suppress the harmonic current further so that the harmonic content of grid-connected current can meet the grid-connected requirements and achieve the three-phase current balance.Finally,the proposed strategy is verified by simulation under the control objectives of the current balance,active power,and reactive power constant.

Reduction of THD in Thirteen-Level Hybrid PV Inverter with Less Number of Switches

Multilevel inverter (MLI) is one of the most efficient power converters which are especially suited for high power applications with reduced harmonics. MLI not only achieves high output power and is also used in renewable energy sources such as photovoltaic, wind and fuel cells. Among various topologies of MLI, this paper mainly focuses on cascaded MLI with three unequal DC sources called asymmetric cascaded MLI which reduces the number of power switches. Various modulation techniques are also reviewed in literature [1]. In this paper we focus on sinusoidal (or) multicarrier pulse width modulation (SPWM) which improves the output voltage at lower modulation index for obtaining lower Total Harmonic Distortion (THD) level. The gating signal for the 13-level hybrid inverter using SPWM technique is generated using Field Programmable Gate Array (FPGA) processor. The proposed modulation technique results in reduced percentage of THD, but lower order harmonics are not eliminated. So a new technique called Selective Harmonic Elimination (SHE) is also implemented in order to reduce the lower order harmonics. The optimum switching angles are determined for obtaining minimum THD. The performance evaluation of the proposed PWM inverter is verified using an experimental model of 13-level cascaded hybrid MLI and compared with MATLAB/SIMULINK model.

Fast SHEPWM Solution Method for Wind Power Converter Based on State Equations

Selective harmonic elimination pulse width modula-tion(SHEPWM)is a modulation strategy widely used for three-level wind power grid-connected converters.Its purpose is to eliminate specified sub-low frequency harmonics by controlling switching angle.Furthermore,it can reduce fluctuation of the microgrid system and improve system stability.Intelligent al-gorithms have been applied to the SHEPWM solution process to mitigate calculation complexity associated with the algebraic method,as well as the need to set the initial value.However,disorder of the optimization result causes difficulty in satisfying incremental constraint of the three-level NPC switching angles,and affects the success rate of the algorithm.To overcome this limitation,this paper proposes a fast SHEPWM strategy to optimize the result obtained by the intelligent algorithm.The SHEPWM can be realized by solving switching angles through a state equations-based mathematical model,which is constructed by using the initial variables randomly generated by the intelligent algorithm as the disturbance.This mathematical model improves the success rate of calculation by simplifying constraint representation of switching angles and solving the disorder problem of the optimization result.At the same time,a method based on the circle equation and the trigonometric function is applied to the initial variable assignment of the state equation,which further improves the speed and accuracy of the solution,realizes a more thorough filtering effect,and further reduces the impact of sub-low frequency harmonics on a wind power integrated system.Finally,simulation and experiment results have been used to prove the effectiveness of the proposed SHEPWM strategy when combined with intelligent algorithms.Index Terms-Wind power converter,adaptive genetic algorithm,selective harmonic elimination pulse-width modulation(SHEPWM),state equation,success rate.

A Novel Approach for Mitigating Power Quality Issues in a PV Integrated Microgrid System Using an Improved Jelly Fish Algorithm

A two-step methodology was used to address and improve the power quality concerns for the PV-integrated microgrid system. First, partial shading was included to deal with the real-time issues. The Improved Jelly Fish Algorithm integrated Perturb and Obserb (IJFA-PO) has been proposed to track the Global Maximum Power Point (GMPP). Second, the main unit-powered via DC–AC converter is synchronised with the grid. To cope with the wide voltage variation and harmonic mitigation, an auxiliary unit undergoes a novel series compensation technique. Out of various switching approaches, IJFA-based Selective Harmonic Elimination (SHE) in 120° conduction gives the optimal solution. Three switching angles were obtained using IJFA, whose performance was equivalent to that of nine switching angles. Thus, the system is efficient with minimised higher-order harmonics and lower switching losses. The proposed system outperformed in terms of efficiency, metaheuristics, and convergence. The Total Harmonic Distortion (THD) obtained was 1.32%, which is within the IEEE 1547 and IEC tolerable limits. The model was developed in MATLAB/Simulink 2016b and verified with an experimental prototype of grid-synchronised PV capacity of 260 W tested under various loading conditions. The present model is reliable and features a simple controller that provides more convenient and adequate performance.