Optimization Of Total Harmonic Distortion Research Articles

Total harmonic distortion optimization in a seven level multilevel inverter by the random search heuristic algorithm

In this article, the random search heuristic optimization algorithm is proposed to guarantee that the voltage synthesized by a seven-level multilevel inverter contains the lowest possible total harmonic distortion. The algorithm in this work is presented as an alternative, simple, and easy-to-implement method for solving a set of transcendental mathematical equations of multilevel inverters. The obtained results demonstrate the algorithm's capability to solve the mathematical formulation that minimizes the total harmonic distortion. It is important to highlight that the algorithm was implemented in Matlab®, and the obtained results were validated in a simulation conducted in Simulink®. Equally and not less important, the results were physically implemented in a laboratory prototype of three integrated circuits with H-bridges containing insulated gate bipolar transistors.

Simplified selective harmonic elimination PWM for three‐level five‐phase T‐NPC inverter

SummaryThis paper presents a selective harmonic PWM strategy (HSE‐PWM) to control a five‐phase three‐level T‐NPC inverter. The proposed method aims to reduce switching losses and directly eliminate specific orders of harmonics, while also controlling the fundamental magnitude. MATLAB/Simulink simulations are conducted using an RL load, and the implementation is tested using a simplified method on an STM32F4 controller board. Experimental tests are then carried out to validate the simulation results. Additionally, power losses and efficiency are studied using Plecs software. The paper explores four different cases of switching angles number and proposes three SHE methods: a simple SHE based on Newton Raphson's method, SHE with current THD optimization, and SHE with common mode voltage (CMV) optimization using the PSO algorithm. The proposed methods provide complete control over the fundamental of the output voltage and the selected harmonics while reducing switching losses. A comparison is carried out in terms of voltage waveform, maximum CMV, fundamental magnitude, total harmonic distortion (THD), and power efficiency for the three methods. The paper concludes that the proposed modulation can be useful in high‐power applications.

THD optimization in 15-level asymmetric reduced switch count multilevel PV inverter using optimization algorithms

Philosophers and industries have focused on designing multilevel inverters, which use significantly fewer power switches and dc sources to achieve high power, low switching, and less harmonic output distortion for medium voltage applications. Even so, these multilevel inverters have some downsides like the use of many electronic components, electromagnetic interference (EMI), bulky driver circuit complexity, significant reverse recovery times, and voltage balancing issues. A modern asymmetrical multilevel inverter with fewer switches and drivers than standard topology is introduced in this article. The powerful analogy addresses traditional inverter topologies of a similar structure. The proposed MLI is relatively simple and easy to extend for many output levels. The proposed design of MLI is implemented for 15 level output with precise and high-quality near sinusoidal waveform using seven switches, three dc sources and three diodes and hence the volume, cost and driver circuit complexity is considerably reduced. The novelty in the proposed topology is that reduced ON state semiconductor switching devices. The output of the MLI is evaluated with the parameter of total harmonic distortion (THD). To minimize the THD, optimization algorithms such as GA, PSO, WOA and HHA were implemented at fundamental switching PWM control method. The comparative analysis of these algorithms on proposed inverter performance is integral for this research. The efficacy of this topology enhances the integration of renewable energy sources.

Optimization of Total Harmonic Distortion in Multilevel Photo Voltaic Inverters Using Genetic Algorithm

In this research, an optimization technique known as Genetic Algorithm is applied to multilevel PV inverters in order to design a Total Harmonic Distortion system with reduced harmonics content as well as able to determine the optimal switching angle while maintaining the required fundamental voltage at the same time. The optimization technique can be implemented on any number of levels of multilevel inverters. For instance, an inverter having 7-level configuration is considered as the initial scenario for the upcoming simulations. The working principle of the Genetic Algorithm along with the functionality of the Graphical User Interface system is constructed and analyzed using MATLAB simulation environment. The result of the implemented optimization technique shows the optimal switching angles at various modulation indices as well as the minimum Total Harmonic Distortion of the system. In short, the purpose of the implemented system was greatly achieved in accordance to the set objectives and further improved its efficiency upon successfully overcoming the limitations of previous research works.

Optimization of THD in a cascaded multilevel inverter based on multiple-carrier pulse width modulation and Simulated annealing

Objectives: This paper deals with the reduction of THD (Total Harmonic Distortion) in the voltage output waveform of a four-stage monophasic cascaded multilevel inverter with Multiple-Carrier Sine Pulse Width Modulation (MCSPWM) using the Simulated Annealing Optimization (SAO) technique. Method: The SAO algorithm was employed to calculate the appropriate firing angles for the switching devices of the inverter by mean of finding the best symmetry of the triangular wave, its frequency and the amplitude of the sine wave used in the modulation through of MATLAB. The monophasic multilevel inverter was simulated and evaluated using de SAO algorithm, then, a prototype was implemented for validating the results. Findings: The output waveform of the converter for multiple scenarios, the graphic of the harmonic content and the optimized modulation parameters were obtained in both the simulation and the prototype. The Simulated Annealing algorithm allowed to find the appropriate firing angles for the four-stage multilevel inverter, adjusting the optimal parameters of triangular and sine signals used in MCSPWM modulation, leading to obtaining a low harmonic content in the output waveform (THD less than 5%), using a low number of switching devices. Novelty/Improvement: The proposed technique (Simulated Annealing) permits to find the optimal parameters of modulation waveforms through a heuristic approach avoids the possible issues with local minima. Also, the method applied optimizes the number of necessary switching devices. Keywords: Multilevel Inverter, Multiple Carrier SPWM, Simulated Annealing, THD

Converter Utilization Ratio Enhancement in the THD Optimization of Cascaded H-Bridge 7-level Inverters

In this paper, a new technique for harmonic optimization in cascaded H-bridge 7-level inverters is proposed. The suggested strategy is based on minimizing an objective function which simultaneously optimizes the converter utilization and Total Harmonic Distortion (THD). The Switch Utilization Ratio (SUR) is formulized for both the phase and line-line voltages of a 7-level inverter and is considered in the final objective functions. Based upon the SUR formula, utilization ratio enhancement will reduce the value of feeding DC links, which improves the efficiency and lifetime of the circuit components due to lower voltage stresses and losses. In order to achieve more effective solution in different modulation indices, it is assumed that the DC sources can be altered. Experimental validation is presented based on a three-phase 7-level inverter prototype.