Abstract: In this article a reliable and efficient switching technique has been proposed to decrease the total harmonic distortion. The total harmonic distortion has harmful effects on electrical devices. Also, leads to increase the temperature in neutral wire of distri More
Abstract: In this article a reliable and efficient switching technique has been proposed to decrease the total harmonic distortion. The total harmonic distortion has harmful effects on electrical devices. Also, leads to increase the temperature in neutral wire of distribution transformers due to over current in power system. The total harmonic distortion has improved by using the proposed technique to eliminate the lower order selection harmonic. Using pulse-width modulation technique is requirement as switching pattern to eliminate the selective harmonic. Therefore, an optimized technique has been proposed to eliminate the lower order selective harmonic for a triple level invertors. The efficiency of the proposed method has been validated and justified through a Simulink in MATLAB software. Also, the proposed technique compared with current pulse-width modulation technique.
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Identifying the location, magnitude of nonlinear loads, and the effects of harmonics is one of the most important parts of maintenance planning, troubleshooting, and modification of power systems. Therefore to determine the keying pattern of selective deletion of harmon More
Identifying the location, magnitude of nonlinear loads, and the effects of harmonics is one of the most important parts of maintenance planning, troubleshooting, and modification of power systems. Therefore to determine the keying pattern of selective deletion of harmonics, a new salp congestion algorithm has been used which has been applied to a 7-levels inverter and the results have been investigated in different cases. In the following, first, we discuss how to simulate the 7-levels inverter and the harmonic produced by it in MATLAB software, and then the results of the proposed design are reviewed. The results show that using the proposed design since the output line voltage of the 3phase inverter is used, the harmonic is reduced by more than 5% compared to the ground state. In this case, the overall harmonic value of the line voltage is approximately 14%, which has been reduced by 8.73% by normal implementation with offline calculations and by 8.43% by online calculations, which shows the accuracy and the performance of the proposed algorithm is to reduce the harmonic distortion at the output voltage…
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The multilevel cascade inverter is one of the most widely used power-electronics based interfaces in electrical distribution systems. Due to high losses and harmonics, the switching frequency of the inverter should be low in medium and high power applications. For this More
The multilevel cascade inverter is one of the most widely used power-electronics based interfaces in electrical distribution systems. Due to high losses and harmonics, the switching frequency of the inverter should be low in medium and high power applications. For this reason, the conventional carrier wave-based sinusoidal pulse modulation (PWM) and space vector PWM that have high switching frequencies cannot be used in these applications. The optimal PWM methods for inverters with step modulation result in lower total harmonic distortion (THD) in output voltage than other common modulation methods. However, one of the major disadvantages of these methods is that the optimal switching angles should be determined using the switching table, limiting the application of the optimal PWM. This paper proposes a method for determination of switching angles by using the iterative quadratic programming method. In each iteration, the proposed method calculates the switching angles by solving the quadratic sub equations with equality constraints and linear equations. Also in the appropriate conditions, global and asymmetric convergences are faster, more accurate, and more efficient, and there is no need for much time and memory for switching angles determination. The optimum switching angles minimize the switching frequency, switching losses, and THD in voltage and current of a three-phase cascade multilevel inverter with step modulation. Also, the power circuit breakers are switched on and off only once in each period. The effectiveness of the proposed method is evaluated through simulation case studies in MATLAB environment.
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