Swarm Optimization-Based Modified Selective Harmonic Elimination PWM Technique Application in Symmetrical H-Bridge Type Multilevel Inverters (original) (raw)
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IET Power Electronics, 2018
Multilevel inverters (MLIs) are nowadays extensively used in integration with renewable energy sources and in drives applications. The converter cost and voltage quality improvement are the utmost importance in such application of MLI. A sixswitch seven-level reduced switch symmetrical MLI (6S-7L MLI) is proposed here. Compared to the conventional and similar existing MLI topologies, the proposed MLI uses less active switches and has less driver circuit requirement. A particle swarm optimisation (PSO)-based modified selected harmonic elimination technique is derived and analysed for computing optimal switching angles of proposed 6S-7L MLI to eliminate third-and fifth-order harmonics. Moreover, the performance of the proposed algorithm is compared with the two most commonly used PSO variants. The analysis shows the modified version of PSO is most suitable for optimising the output voltage of proposed MLI through targeted harmonic elimination. The proposed topology is investigated through simulation by applying the calculated switching angles using modified PSO algorithm. Finally, a single-phase experimental prototype is designed to verify the validity of the proposed structure.
so, far several methods have been presented to eliminate & minimize the low order voltage harmonics at multilevel inverter"s output & maintain the fundamental component at the desired value. This paper focus on elimination of harmonics in a cascaded H-bridge 11 level inverter. Two heuristic techniques are implemented to find out the minimum THD in cascade multilevel inverter. Using the mathematical theory of resultants, all solutions to this equivalent problem can be found. Theoretical results are verified by simulation and experiments for an 11-level H-bridge inverter. Results show that the proposed methods effectively eliminate a great number of specific harmonics, and the output voltage is resulted in low total harmonic distortion.
Based Selective Harmonic Elimination for Multilevel Inverter with Reduced Number of Switches
inverters have been used in the power applications to get low total harmonic distortion (THD) in medium or high voltage levels. In order to get low THD in the output voltage, several techniques have been applied to multilevel inverter. One of these techniques is Selective Harmonic Elimination (SHE) that has an extensive research area in the field of power electronics. It is also an alternative to usual PWM techniques and includes nonlinear equations of stepped voltage waveform. In this paper, multilevel inverter with reduced number of switches which enables a reduction in the system cost has been proposed, and solution of SHE equations have been optimized by Genetic Algorithm (GA). The results of simulation and analysis have apparently proved that proposed GA based SHE technique eliminates desired harmonic order.
2019
A new optimization method is proposed in this paper for finding the firing angles in multi-level voltage source inverters to eliminate low-order selective harmonics and reduce total harmonic distortion (THD) value of the output voltage. For thid end, Fourier series is used for calculating objective function and selecting specific harmonics. Regarding the nature and complexity of the employed non-algebraic equations in the optimization problem for achieving the optimal angle in the multi-level inverter, a recent developed meta-heuristic method known as Salp Swarm Algorithm (SSA) is presented. In the proposed method, the optimal angles for a given multi-level inverter are obtained based on the objective function such that the magnitudes of the selective harmonics and the THD value of the output voltage are reduced. The method is applied on a cascaded H-bridge type five-level inverter. The simulation results illustrate that the magnitudes of the selective harmonics and the THD percentage of the output voltage have been reduced through selecting the optimal switching angle by the proposed optimization algorithm. The result of this method are compared with those of SPWM method. Moreover, the performance of SSA algorithm with respect to PSO algorithm is compared which shows its rapid convergence speed and less THD value.
Microsystem Technologies, 2018
This paper presents, ant colony optimization based hybrid algorithm for selective harmonic elimination in single phase seven level multilevel inverter with reduced switches. For high power and high voltage applications, multilevel structure with selective harmonic elimination (SHE) modulation scheme is used. The output voltage of multilevel inverter contains fundamental component along with harmonics. SHE technique aims to solve non-linear transcendental equations maintaining the fundamental harmonic component to its desired value and to eliminate lower order odd harmonics. Many optimization algorithms have been implemented to solve this problem. But these algorithms are complicated and time consuming. The Newton-Raphson algorithm is also very convergent for solving these non-linear equations. The main disadvantage of this method is, it requires strong initial guess. To overcome these drawbacks, hybrid optimization algorithm is used in this paper. This algorithm is performed in two stages, during first stage ant colony optimization has been run and in second stage the solutions obtained from ACO is used as a initial guess for Newton-Raphson algorithm which confirms the exact converged solution. Thus the drawback of Newton's method i.e. requirement of good initial guess is overcomed by proposed hybrid algorithm. The MATLAB/SlMULINK software is used for comprehensive simulation of seven-level inverter. Experimental results validate the simulated results.
Implementing selective harmonic elimination in multilevel inverters with optimal dc source
e-Prime, advances in electrical engineering, electronics and energy, 2024
In this paper, the bird swarm algorithm (BSA) is proposed for selective harmonic elimination (SHE) implementation in seven-level inverters. The SHE technique reduces switching frequency and, as a result, inverter losses, by using BSA to expedite the process of identifying optimal switching angles. The computational load is substantially reduced by BSA-based SHE-pulse width modulation (SHE-PWM), in contrast to conventional techniques that require solving transcendental nonlinear trigonometric equations. Furthermore, SHE-pulse amplitude modulation (SHE-PAM) removes additional harmonics from the output voltage of inverter by optimizing both the switching angles and the amplitude of the dc source voltage. This improved technique allows for more flexibility, eventually leading to a decrease in total harmonic distortion. SHE-PWM and SHE-PAM are shown to be effective for a seven-level inverter through a simulation study in the MATLAB/Simulink environment and an experimental study on a laboratory prototype.
HARMONICS REDUCTION IN CASCADE H-BRIDGE MULTILEVEL INVERTERS USING GA AND PSO by Aman Parkash
This paper presents the mitigation of total harmonic distortions (THD) in cascade H-bridge multilevel inverter. Selective harmonic elimination pulse width modulation (SHE-PWM) switching method is used to calculate the values of switching angles from the solution of non-linear transcendental equations. These non-linear complex equations is minimized by the using of particle swarm optimization (PSO) and genetic algorithm (GA) techniques, and also have been compared the simulating and analyzing results related to harmonics.
International Journal of Power Electronics and Drive Systems (IJPEDS), 2021
Renewable energy has a great importance for power generation as it does not use the fossils fuels. Energy generated from alternative energy sources are weather dependent. To generate a continuous power to meet the load requirements, Battery energy storage system are used. Power conversion process must be much efficient as possible to convert the DC stored energy into AC. This conversion process is usually done by the help of inverters. This paper gives the brief overview on three main categories of multilevel inverter like cascaded h-bridge, neutral point clamped and flying capacitor multilevel inverter and highlights their advantages which can also help the scholars to deeply explore the categories of multilevel inverter. Harmonic elimination is usually done by controlling the switching angles of the inverter. Among all the switching angles techniques, selective harmonic elimination pulse width modulation (SHEPWM) technique is widely used, that has also discussed in this paper. Furthermore, to eliminate the harmonics using SHEPWM, it has the set of nonlinear transcendental equations, these set of equations can be effieceintly solved by the optimization methods. The most efficient and reliable optimization method like particle swarm optimization has been discussed with multiple objective functions in this paper. This paper will help the scholars to understand the finest category of multilevel inverter for harmonic elimination in terms of efficiency and output quality.
—In this paper, a new topology of multi-level inverter with minimum number of switching components is adopted. This topology provides a higher number of output voltage levels with lower switching components compared to conventional multilevel inverters. This is achieved throughout the unsymmetrical choice of D.C sources magnitudes. This topology consists of series connected units; each unit has only two switches and the output voltage can be obtained throughout two stages. Among the several control techniques of multilevel inverters, the fundamental switching frequency modulation is preferred to minimize the switching losses. The selective harmonic elimination technique is used to eliminate specified harmonics using genetic algorithm to compute the optimum switching angles of inverter switches and minimize the total harmonic distortion. Simulation results are given for 15-level single phase multilevel inverter system operation when using genetic algorithm compared with equal step technique.
Electronics
Multilevel inverters (MLI) are popular in high-power applications. MLIs are generally configured to have switches reduced by switching techniques that eliminate low-order harmonics. The selective harmonic elimination (SHE) method, which significantly reduces the number of switching, determines the optimal switching moments to obtain the desired output voltage and eliminates the desired harmonic components. To solve the SHE problem, classical methods are primarily employed. The disadvantages of such methods are the high probability of trapping in locally optimal solutions and their dependence on initial controlling parameters. One solution to overcome this problem is the use of metaheuristic algorithms. In this study, firstly, 22 metaheuristic algorithms with different sources of inspiration were used to solve the SHE problem at different levels of MLIs, and their performances were extensively analyzed. To reveal the method that offers the best solution, these algorithms were first a...