Optimum Modulation Index Selection in Multilevel Inverter Using Selective Harmonic Elimination (original) (raw)
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A novel optimization harmonic elimination technique for cascaded multilevel inverter
Bulletin of Electrical Engineering and Informatics, 2019
The main goal of utilizing Selective Harmonic Elimination (SHE) techniques in Multilevel Inverters (MLI) is to produce a high-quality output voltage signal with a minimum Total Harmonic Distortion (THD). By calculating N switching angles, SHE technique can eliminate (N-1) low order odd harmonics of the output voltage waveform. To optimized and obtained these switching angles, N of nonlinear equations should be solved using a numerical method. Modulation index (m) and duty cycle play a big role in selective harmonic elimination technique to obtain a minimum harmonic distortion and desired fundamental component voltage. In this paper, a novel Optimization Harmonic Elimination Technique (OHET) based on SHE scheme is proposed to re-mitigate Total Harmonic Distortion. The performance of seven-level H-bridge cascade inverter is evaluated using PSIM and validated experimentally by developing a purposely built microcontroller-based printed circuit board. 1. INTRODUCTION The rapid development of power electronic devices, better be called renewable energy electronics, has effectively contributed to find more utilization of renewable energy applications in wind and solar energy. DC/AC inverter has become more interesting for interfacing between renewable sources and the grid in order to invert the energy from DC to AC form [1-4]. Recently, Multilevel Inverters (MLIs) have become more popular in photovoltaic (PV) applications. These topologies are mainly utilized in high and medium power practical applications because of their capacity to generate a high-quality output signal with decreased switch loss by power switches employed [5, 6]. However, multilevel inverters include a number of cells of power semiconductor devices which suffer from some challenging issues in more complex topologies [7]. By increasing the number of levels the quality of the output wave shape improves with minimizing THD and making the output closer to a sinusoidal signal [8]. The suitable topology for medium and high power application is Cascaded full bridge multilevel inverter. The control circuit of this kind of inverters is simpler than other topologies [9]. Also, it can be easily extended to higher levels to produce high power by adding more units of H-Bridge on the series connection. The main disadvantage of the cascade multilevel inverter is the large number of DC voltage sources wanted to feed all the H-bridge cells, and hence all these DC sources have to be isolated [10]. However, it can reduce the switching losses and eliminate the effect of harmonic spikes from the output waveform with higher efficiency [11]. The THD of the multilevel inverters output voltage must be a minimum value.
Simulation Modelling on Harmonic Reduction Using Cascaded Multilevel Inverter fed Induction Drive
Abstract: In this project, a multilevel inverter was designed and implemented to operate a stand-alone solar photovoltaic system. The proposed system uses selective harmonics elimination pulse-width modulation (PWM) in the multilevel inverter to convert DC voltage from battery storage to supply AC loads. In the PWM method, the effectiveness of eliminating loworder harmonics in the inverter output voltage is studied and compared to that of the sinusoidal PWM method. This work also uses SHEPWM to predict the optimum modulation index and switching angels required for a nine-level cascaded Hbridge inverter with improved inverter output voltage. The proposed predictive method is more convincing than other techniques in providing all possible solutions with any random initial guess and for any number of levels of a multilevel inverter. The simulation results prove that the lower-order harmonics are eliminated using the optimum modulation index and switching angels. An experimental system was implemented to demonstrate the effectiveness of the proposed system
9-Level Single DC Voltage Source Inverter Controlled Using Selective Harmonic Elimination
International Journal of Power Electronics and Drive Systems (IJPEDS)
This paper presents an efficient cascaded H-bridge inverter topology that is controlled using an optimized selective harmonic elimination pulse width modulation technique. The switching angles are obtained by solving the nonlinear transcendental equation with the aid of genetic algorithm optimization method. Unlike the usual H-bridge converter topologies that require multiple individual direct current (DC) sources and additional switching components per voltage step, the proposed topology utilizes a single DC source to supply two full-bridge modules. The modified topology employs a cascaded multi-winding transformer that has two independent primary windings and series-connected secondary side with 1:E and 1:3E turn ratios. The converter topology and switching function are proven to be reliable and efficient, as the total harmonic distortion (THD) is quite low when compared with the conventional H-bridge topology controlled by other modulation techniques. This feature makes it attractive to renewable energy systems, distributed generation, and highly sensitive equipment such as those used in medical, aerospace, and military applications. The topology is simulated using a PSIM package. Simulation results show that all the 11level lower order odd harmonics are eliminated or suppressed in compliance with the SHE elimination theorem of (N-1).
9-Level Voltage Source Inverter Controlled Using Selective Harmonic Elimination
International Journal of Power Electronics and Drive System (IJPEDS), 2018
This paper presents an efficient cascaded H-bridge inverter topology that is controlled using an optimized selective harmonic elimination pulse width modulation technique. The switching angles are obtained by solving the nonlinear transcendental equation with the aid of genetic algorithm optimization method. Unlike the usual H-bridge converter topologies that require multiple individual direct current (DC) sources and additional switching components per voltage step, the proposed topology utilizes a single DC source to supply two full-bridge modules. The modified topology employs a cascaded multi-winding transformer that has two independent primary windings and series-connected secondary side with 1:E and 1:3E turn ratios. The converter topology and switching function are proven to be reliable and efficient, as the total harmonic distortion (THD) is quite low when compared with the conventional H-bridge topology controlled by other modulation techniques. This feature makes it attractive to renewable energy systems, distributed generation, and highly sensitive equipment such as those used in medical, aerospace, and military applications. The topology is simulated using a PSIM package. Simulation results show that all the 11level lower order odd harmonics are eliminated or suppressed in compliance with the SHE elimination theorem of (N-1).
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.
International Journal on Electrical Engineering and Informatics, 2021
Numerous techniques have been used in the literature to produce switching signals in multilevel inverters (MLIs). Reducing the number of switching component in multilevel inverters is another area of interest in the literature. In this paper, a MLI with low switching number has been designed and worked successfully in harmonic elimination method. For this purpose, a novel genetic algorithm based SHE-PWM in a single phase 11-level inverter is presented in order to eliminate the switching signals. Also, total harmonic distortion (THD) analysis, which depends on switching angles for multilevel inverters, in a wide modulation range of 11-level inverter topology is presented. Hence, the switching angles are first estimated by Genetic Algorithm (GA) method, in which a certain number of harmonic components are eliminated. THD analysis is performed using both analytical and MATLAB simulation using calculated switching angles. The proposed method is applied to an 11-level inverter to eliminate 3th, 5th, 7th and 9th harmonic content in the range of modulation index 1.5 and 4. A simulink model which provides simulating and validating the accuracy, dynamics and continuity of the GA solution, was created. Experimental validation is not carried out in this study. Considering the simulation results and similar studies in the literature, the success of the reduced inverter topology and GA supported harmonic elimination technique was observed.
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/selective-harmonic-elimination-pwm-method-using-seven-level-inverters-by-genetic-algorithm-optimization-technique https://www.ijert.org/research/selective-harmonic-elimination-pwm-method-using-seven-level-inverters-by-genetic-algorithm-optimization-technique-IJERTV4IS020583.pdf This paper proposes a method for optimization of the harmonic performance of inverters under selective harmonic elimination PWM modulation (SHEPWM) control. SHEPWM method is used to optimize harmonic stepped waveform for multi-level inverters using Genetic algorithm. It involves the solution of non-linear transcendental equation sets representing the relation between the amplitude of the fundamental wave, harmonic components and the switching angles. The genetic algorithm obtains the being optimal solution set of switching angles for each obligatory harmonic profile. Optimized SHEPWM sequences obtained for various operating points under different sampling frequencies are exposed to result in significant reduction of major harmonics while upholding the waveform quality inside prescribed limits.
Harmonic Minimized of Cascaded H-Bridge Multilevel Inverter Using PV system
volume 1, issue 1, Feb-2014, IJRST
This paper focusing on the harmonic minimization of 11-level cascaded H-multilevel inverter using PV systems with a Pulse Width Modulation (PWM) control scheme. The photo-voltaic arrays are connected to eleven level multilevel inverter through DC-DC boost converter. By implementing maximum power point tracking (P&O) algorithm are producing power from PV array. The DC power from the PV array is boosted by using the DC-DC boost converter. Which is controlled by PI controller. This methodology of simulation has been carried out and verified through the MAT LAB/SIMULINK to achieve a mitigated Total Harmonic Distortion (THD).
Granthaalayah Publications and Printers , 2023
Considering present shortage of fossil fuels and discharges of ozone harming substances, power developed from Renewable Energy Sources (RES) is identified as the excellent choice for producing the electricity. The characteristic of an inverter is to transform the dc power into ac power to fulfill out the requirements of load. Despite its advantage, the presence of harmonics in the output voltage reduces both the efficiency and the performance of the inverter. Several researches have been carried out since last three decades for eliminating the harmonics. Based upon several researches, it reveals that the Selective Harmonic Elimination Pulse-width Elimination technique (SHEPWM) has proven to be the best in eliminating lower order harmonics. But when calculus based methods are used for solving the non-linear transcendental equations, this technique has shown some complications. Artificial Intelligence (AI) techniques appear to be better in solving the above said equations. This review paper provides the performance of some AI techniques used for eliminating the harmonics in inverters. Based upon the information collected from various literatures and its results, conclusion has been made.
Selective Harmonic Elimination Modulation Method For Multilevel Inverters
Multilevel converter technology has recently emerged as a very important alternative in the area of high-power applications. Several modulation methods have been applied to multilevel Inverters. The modulation methods with higher switching frequency reduce filter size but increases switching losses. The Step modulation method operates with low switching frequency has less switching losses but it requires large filter size. To reduce the filter size the number of levels of the inverter is increased but it increases the cost of the system. This paper presents a novel modulation method where additional notches are introduced in the multi-level output voltage. These notches eliminate harmonics at the low order/frequency and shifts it a higher order/frequency and hence the filter size is reduced without increasing the switching losses and cost of the system. The proposed modulation method is verified through simulation and such results are also validated practically using a five-level Diode-clamped inverter prototype.