scholarly journals Pulse Multiplication in the Self-Commutating Parallel Converter by Means of Multi-Level DC Voltage Reinjection

Author(s):  
Yonghe Liu ◽  
Bernard Perera ◽  
Jos Arrillaga ◽  
Neville R. Watson

A multi-level dc voltage reinjection concept is described that multiplies the pulse number of the twelve-pulse dual parallel converter. The ideal reinjection waveform for complete elimination of the harmonic content is first derived, and a practical approximation is proposed which converts the standard dual converter into a sixty-pulse scheme, thus meeting the strictest harmonic standards without the assistance of filters or Pulse Width Modulation.

2018 ◽  
Vol 7 (3.1) ◽  
pp. 42
Author(s):  
B Kandavel ◽  
G Uvaraj ◽  
M Manikandan

This paper presents comparative study of Total Harmonic Distortion (THD) and its individual harmonic contents without grid and with grid for Diode clamped multi level inverter (DCMLI) and Flying capacitor clamped multilevel inverter (FCMLI) based Doubly Fed Induction Generator (DFIG) employing PI and Fuzzy logic controller (FLC). Simple method to control for a variable speed wind energy conversion system with a DFIG is connected to the grid through a diode rectifier and a diode clamped multilevel inverter (DCMLI). The DC-link voltage is controlled through a DC-DC boost converter to keep the DC voltage at constant value. Inverter is controlled by sinusoidal pulse width modulation technique, which supplies power to the grid. The THD and its harmonic content are studied for different wind speeds. DFIG fed flying capacitor multi level inverter (FCMLI) based WECS connected to load as well as grid. FCMLI is controlled through sinusoidal pulse width modulation. Voltage and current harmonics are studied. The results of both multilevel inverters are compared. It shows that the level of harmonic content of two types of multilevel inverters working at different wind speeds indicates that Total Harmonic Distortion (THD) for DCMLI has given best results.  


This paper deals with sensorless vector controlled induction motor in which torque pulsations are reduced with improved input of induction motor. In proposed technique two multi winding transformers are used for generation of 18 sinusoidal signals given to rectifier unit and the rectifier output given as input to 9 level multi level inverter. In this proposed technique gating signals to the inverter switches will be provided through space vector pulse width modulation which considers speed as reference. This configuration was simulated in MATLAB/Simulink.and the simulation results are presented here with improvement in reduction of THD.


2016 ◽  
Vol 25 (09) ◽  
pp. 1650108 ◽  
Author(s):  
P. Karuppusamy ◽  
G. Vijayakumar ◽  
S. Sathishkumar

This paper presents a photovoltaic (PV) system to convert the solar energy into electrical energy. DC power from PV system is converted into AC power using multilevel inverters. Cascaded H-bridge (CHB) inverter and diode clamped inverter (DCI) are used to convert variable DC power into sinusoidal AC power. Harmonic content is the important part to improve the efficiency of the inverter. Harmonics of CHB inverter and DCI are simulated and analyzed with different pulse width modulation (PWM) techniques.


2020 ◽  
Vol 8 (5) ◽  
pp. 5180-5185

Paper Setup must be in A4 size with Margin: Top In the present paper multi carrier sinusoidal modulation technique which is an efficient method of producing control signals is used for a symmetrical inverter with several levels in cascade H Bridge is discussed. The Cascaded H-Bridge performance output levels depend on the DC voltage sources used at the input side. With the help of two DC voltage sources, five level output can be obtained whereas three sources gives levels of seven in output voltage. In this paper, multi-carrier SPWM switching is obtained for switching of multilevel inverter based switches. Two signals are used in this switching method, among which one of the signals is reference which is a low frequency sinusoidal signal and the one is a carrier signal. In case of sinusoidal PWM method of modulation technique, the reference signal is a sinusoidal one and triangular signal can be used as a carrier signal. These types of inverters have the ability to generate inverted output voltage with an efficient harmonic spectrum and reliable output results. This document provides switching signal for H-bridge inverter structure which can improve harmonic performance. The 5-level multilevel inverter is simulated for traditional carrier-based pulse-width modulation (PWM) phase change carrier techniques. The total harmonic performance of the output voltages is analyzed for the two PWM control methods. The performance of the symmetrical PWM CHB is simulated using MATLAB-SIMULINK model. Model results show that THD can be minimized to a limit with level shifted modulation method of the sinusoidal pulse width. The results from the simulations show that the quality of the waveform of the output voltage improves with less loss and with a lower THD.


Author(s):  
Mr.A.VinothKumar ◽  
Dr.S.Vijayabaskar ◽  
Ms.C.Selsiya

The demand for clean and sustainable energy has prompted research into all types of renewable energy sources, including solar energy generated by photovoltaic systems. We suggest a new multi level inverter topology in this paper. This paper looks at a PV-based 13-level multi level inverter with fewer switches. The most gainful power converters for high power applications and modern applications with fewer switches are multi level inverters. PWM methodology is used to manage the proposed topology. The proposed topology has one of the highest efficiency and lower voltage THD. The inverter produces output voltage in thirteen levels: Vdc, Vdc/2, Vdc/3, Vdc/4, Vdc/5, Vdc/6, 0, -Vdc, -Vdc/2, -Vdc/3, -Vdc/4, -Vdc/5 and -Vdc/6. The validity of the proposed inverter is verified through simulation. KEY WORDS: Pulse Width modulation (PWM), Photo Voltaic (PV) Source.


2020 ◽  
Vol 3 (2) ◽  
pp. 1-17
Author(s):  
Ahmet Mete VURAL ◽  
Ali Osman ARSLAN ◽  
Mustafa DENİZ

In recent years, multi-level inverters have emerged as a feasible power conversion solution for medium and high power applications due to better harmonic performance and ability to operate at high voltage/power when compared to traditional two-level inverters. Since the output level of the multi-level inverters depends on the number of the switching elements, as more levels are required, more switching elements are used. This situation makes the circuit and the control design complex and the losses to upsurge. To overcome these limitations and produce low harmonic content at the output, reduced switch count topologies are popular. In this study, a single-phase asymmetric hybrid multi-level inverter is proposed by combining diode clamped and cascaded H-bridge topologies. The inputs of the proposed inverter are selected as two unequal DC voltage sources. In this regard, fewer switching elements are used to obtain the same number of voltage levels at the output when compared to traditional multi-level inverters. The efficiency and the harmonic performance of the proposed topology is both verified by simulation and experimental studies. The gating signals of the semiconductor switches are produced by phase disposition pulse width modulation with carriers’ frequency of 4 kHz. It is shown by the experiments that a maximum efficiency of 94 % and a total harmonic distortion of 29 % are attained in the case studies.


Author(s):  
Sony Prakarsa Putra ◽  
Zulwisli Zulwisli

This study aims to create a PWM inverter that can drive the Brushless Unidirectional Flow Machine (MASTS). PWM inverters are intended to correct deficiencies in six-step inverters. Inverter is a circuit that is used to convert a DC voltage source into an AC voltage with a certain frequency. The use of inverters is found in electric vehicles. The system often used to control an inverter is a Pulse Width Modulation (PWM) based control, where pulse width is used to regulate speed. The inverter is tested using 3 pairs of mosfets as a switch to control the three-phase output of the inverter. In the inverter, PWM is used to adjust the width of the frequency pulse that will be given to the mosfet. This research used 3 variations of duty cycle 30%, 60%, 90% to determine the effect of MASTS speed on PWM by using a PWM inverter. The results of this study the speed of MASTS can be influenced by changes in duty cycle, with increasing value of the duty cycle, the faster the speed of MASTS, and vice versa. Keywords:Mosfet, Sensor Hall, MASTS, PWM, Inverter.


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