scholarly journals Analysis Of 12- Level Cycloconverter To Minimize Thd (Total Harmonic Distortion) Level In 3-Phase Induction Motor

Author(s):  
Mallepally Narendar Reddy, Et. al.

These harmonics are higher than essential frequencies and cause Total Harmonics Distortion (THD) which increases the rms current and generates more warmth in the load. Numerous techniques are used to suppress the harmonics to limit the warmth in the load. Another procedure is utilized in this work to limit THD and the method to beat the low exhibition of a traditional PWM (pulse width tweak) control. In this work, the desired output voltage is accomplished by contrasting the desired sinusoidal waveform (adjusting signal) with a high frequency three-sided waveform (transporter signal). Industrial applications demands high force and long life expectancy motor drives. Three phase motor drives have restricted force density consequently Multiphase motor drives are better solutions for high force density and substantial loads. In this work a 12 level cycloconverter is designed to drive three Phase load. The loads used in the industries almost nonlinear loads like motors. Thusly, because of these nonlinear loads extra harmonics incited at the output of the 12 level cycloconverter drive with major frequency. The harmonics and THD got using our proposed technique is thought about using Mat lab/Simulink

2021 ◽  
Author(s):  
Mei Li

This thesis presents the introduction, analysis and experimental verification of the six-pulse SCR rectifier and multi-pulse SCR rectifiers. As a fundamental three-phase controllable ac-dc converter, the six-pulse SCR rectifier is widely used in industry. However, it generates high Total Harmonic Distortion (THD) in the line current. One of the solutions is to use multi-pulse rectifiers. Multi-pulse rectifiers could be classified into the 12-, 18-, and 24-pulse configurations. Application examples include high voltage direct current transmission systems, high power battery chargers and load commutated current source inverter powered motor drives. In this thesis, the six-, 12-, 18- and 24-pulse SCR rectifiers with inductive and capacitive loads are introduced. The line current THD and the input PF of various rectifiers are investigated. The principle of the harmonic elimination through phase-shifting transforms is analyzed by Fourer analysis and positive/negative sequence analysis. The experimental verification is accomplished on a prototype of the 12-pulse SCR recitifier.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Z. Chelli ◽  
R. Toufouti ◽  
A. Omeiri ◽  
S. Saad

This paper focuses on a four-wire shunt active power filter (APF) control scheme proposed to improve the performance of the APF. This filter is used to compensate harmonic distortion in three-phase four-wire systems. Several harmonic suppression techniques have been widely proposed and applied to minimize harmonic effects. The proposed control scheme can compensate harmonics and reactive power of the nonlinear loads simultaneously. This approach is compared to the conventional shunt APF reference compensation strategy. The developed algorithm is validated by simulation tests using MATLAB Simulink. The obtained results have demonstrated the effectiveness of the proposed scheme and confirmed the theoretical developments for balanced and unbalanced nonlinear loads.


Author(s):  
Olwi A. Elkholi ◽  
Mohamed A. Enany ◽  
Ahmed F. Abdo ◽  
Mahmoud Eid

<p class="Abstract">Due to their better DC bus utilization and easier digital realization, Space Vector Pulse Width Modulation (SVPWM) scheme is the most widely used PWM scheme. Also two level inverter is the traditional frequency converter because it has fewer components and is lower complex to control, but on the other hand it generates higher harmonic distortion. This paper presents the realization of novel SVPWM approaches applied to the three phase induction motor drives. Specifically various schemes are based on using more combinations of step operation in each cycle to approximate the reference vector, such as 24 and 48 step operations in each cycle. The basic principle of conventional SVPWM with different modulation index M is presented. The switching sequences of new approaches are described. The modulation signals waveforms, DC bus voltage utilization, De-rated motor torque, standard error of average torque, voltage and current harmonic of new approaches are analyzed by the MATLAB/SIMULINK software. The results confirms that 48 step SVPWM approach is the best compared to other approaches.</p>


Author(s):  
Mo. Suhel A. Shaikh ◽  
Rakesh Maurya

Abstract This paper deals with the performance analysis of different PWM techniques for three-phase and dual three-phase induction motors. In this paper, the dual three-phase induction motor is reconnected as a three-phase and six-phase winding configurations and its performances are investigated. The comparative evaluation for the aforesaid machine configurations are carried out in terms of quality of stator current waveform with different PWM techniques. Total harmonic distortion are obtained in terms of harmonic distortion factor for stator current. The theoretical findings are further verified through simulation and experimental results.


2017 ◽  
Vol 13 (1) ◽  
pp. 73-82
Author(s):  
Mohammed Ali

In this paper describe to mathematical analysis for a three-phase, two level inverter designs. As we know the power electronic devices (inverter) to convert the DC power to AC power (controller on output voltage and frequency level). In Industrial applications, the inverters are used for adjustable speed (AC Drives). In this paper, the mathematical analyses for inverter design are done by using Software packages C++ Builder and visual C++ Language. For non- linear distortions described by the load power factor in power system networks. The P.F is reverse proportional with the harmonics distortion. Small P.F means much more of harmonic distortion, and lower power quality for consumers. to improve the P.F, and power quality in this paper the small capacitor installed as part of the rectified the load current has power (30 KW with P.F load 0.8), the fluctuations of the rectified voltage must not greater than +/- 10%.The power factor proportion of the load power, with Modulation coefficient p.u approximately unity. The calculation is achieved with different integrations steps with load power 30KW, 0.8 P.F. all results done Based on model and experimental data.


IJOSTHE ◽  
2020 ◽  
pp. 1-10
Author(s):  
Rahul Dhakad ◽  
Dr. Rakesh Saxena

The electrical distribution system is facing undesirable power quality disturbances due to different types of linear/nonlinear loads on the supply system. The objective of the project is to reduce the distortion level in voltage or current input to the load and at the output of the filter. To design a simple but highly viable hybrid active power buffer that is capable of feeding less distorted voltage to the nonlinear load model. To present an optimal controlling of these buffers so as to minimize the voltage distortion by designing a different algorithm for the same. Comparing the THD levels of the output voltage waveform with the standard controlling method with the proposed control design to further enhance the proposed design such that it is practically feasible to be implemented in grid system having renewable energy resources. In this work, a power filter has been designed using different algorithms with an objective to reduce the Total Harmonic Distortion in the voltage output waveforms. The total harmonic distortion in the voltage output waveform being fed to the load using only the PQ_RLS algorithm is found to be 2.18 %. In the case of the output voltage from the power buffer using PQ_RLS algorithm, the THD level is 0.17 %. The distortion level in the output voltage waveforms in both the cases being fed to the load when compared, it is found that RLS algorithm in combination with PQ algorithm is more effective in reducing the distortion as compared to standard RLS method or PQ method.


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