scholarly journals Analysis and improvement of the efficiency of frequency converters with pulse width modulation

2019 ◽  
Vol 9 (4) ◽  
pp. 2314
Author(s):  
Bogdan Vasilev
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Frequency Converter ◽  
Spectral Composition ◽  
Leading Edge ◽  
Maximum Frequency ◽  
Distortion Factor ◽  
Frequency Converters ◽  
Harmonic Composition

In order to identify the best control algorithm, the effects of modulation control algorithms on the energy characteristics of a two-level autonomous frequency converter inverter were studied. The research was carried out by the methods of mathematical and simulation modeling. The equa-tions of mathematical description were compiled taking into account a number of generally accepted assumptions. An equivalent circuit of a two-level autonomous inverter was created. Comparisons of pulse-width modulation algorithms with carrier signals of various shapes and frequencies were made. Three different forms of carrier signal were used: triangular, sawtooth with a falling edge and sawtooth with a leading edge. Studies were conducted at frequencies of 3,000, 6,000 and 9,000 Hz. Conclusions were made about the identity of the spectral composition of the front and rear edges of the sawtooth signal, it was also noted that with the triangular waveform, being the part of the har-monics, present in the sawtooth form is removed, so, the triangular shape provides the best result of the autonomous inverter. Also, by increasing in the carrier frequency, it was noted that pulse packets appear at different harmonic numbers, shift, and the amplitude and distortion factor decrease, that means, the best performance was obtained at the maximum frequency studied. In the study of the voltage at the output of the chokes at different frequencies of the carrier signal, it was noted that at a higher frequency, the ripple of the output voltage decreases. Throttles do not eliminate harmonics, but only reduce their amplitude. Based on the results, it was concluded that the algorithm with a triangular carrier signal and the maximum frequency provides the best harmonic composition of the output voltage of the frequency converter.

scholarly journals Reconfiguration of a Multilevel Inverter with Trapezoidal Pulse Width Modulation

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2148 ◽  
Author(s):  
Nataraj Prabaharan ◽  
V. Arun ◽  
Padmanaban Sanjeevikumar ◽  
Lucian Mihet-Popa ◽  
Frede Blaabjerg
Keyword(s):  
Root Mean Square ◽  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Harmonic Distortion ◽  
Multilevel Inverter ◽  
Mean Square ◽  
Distortion Factor ◽  
Field Programmable ◽  
Trapezoidal Pulse

This paper presents different multi-carrier unipolar trapezoidal pulse width modulation strategies for a reduced switch asymmetrical multilevel inverter. The different strategies are phase disposition, alternative phase opposition and disposition, and carrier overlapping and variable frequency that involve triangular waves as carriers with a unipolar trapezoidal wave as a reference. The reduced switch, asymmetrical multilevel inverter operation was examined for generating the seven-level output voltage using Matlab/Simulink 2009b and the results were verified with a real-time laboratory-based experimental setup using a field-programmable gate array. Different parameter analyses, such as total harmonic distortion, fundamental root mean square voltage, and distortion factor, were analyzed with different modulation indices to investigate the performance of the selected topology. Unipolar trapezoidal pulse width modulation provides a higher root mean square voltage value.

scholarly journals Method for reducing the amplitudes of higher harmonics in the output voltage of the frequency converter

2021 ◽  
Vol 29 (1) ◽  
pp. 120-132
Author(s):  
Alexsandr V. Starikov ◽  
Sergey L. Lisin ◽  
Olga S. Belyaeva ◽  
Viktor A. Kirdyashev
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Dead Time ◽  
Frequency Converter ◽  
Higher Harmonics ◽  
Sinusoidal Modulation ◽  
Power Transistors ◽  
Switching Power ◽  
Sinusoidal Pulse Width Modulation

Modern low-voltage frequency converters, built on the principle of stand-alone inverters with pulse-width modulation, have large amplitudes of higher harmonics in the output voltage. This adversely affects the operation of an asynchronous or synchronous motor connected to such a converter, since it causes a decrease in the efficiency of the AC machine. The analysis of the reasons for the poor harmonic composition of the output voltage of traditional inverters with sinusoidal pulse-width modulation is carried out and it is noted that the main one is the introduction of "dead" time when switching half-bridges every modulation period. The proposed method of sinusoidal modulation does not require the introduction of "dead" time. The modes of operation of power transistors with this switching method and control signal diagrams are considered. Analytical expressions are found that make it possible to determine the effective value of the output voltage of the frequency converter and the coefficients of higher harmonics for the proposed method of switching power transistors. The main reason for the low effective value of the phase voltage at the output of the inverter at sinusoidal pulse-width modulation is determined - the ineffective use of the switching period. The proposed method of sinusoidal modulation does not require the introduction of "dead" time, increasing the effective value of the output voltage and reducing the total harmonic component by 75 times. The diagrams of signals that control power transistors and provide a decrease in the amplitudes of higher harmonics at the output of the frequency converter are given. An approximation by the harmonic Fourier series of the output voltage of the inverter, obtained in the case of using the proposed method of switching power transistors, is made. It is noted that for the technical implementation of sinusoidal modulation, which provides small amplitudes of higher harmonics, only two pulse-width modulators are needed.

scholarly journals Research on Modified Hybrid Frequency Modulation Technology of Type-III Asymmetric CHB Multilevel Inverters

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 263
Author(s):  
Manyuan Ye ◽  
Wei Ren ◽  
Qiwen Wei ◽  
Guizhi Song ◽  
Zhilin Miao
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Output Line ◽  
Line Voltage ◽  
Multilevel Inverters ◽  
Type Iii ◽  
Hybrid Frequency ◽  
Frequency Pulse

Asymmetric Cascaded H-bridge (ACHB) level inverters can output more voltage waveforms with fewer cascaded units while ensuring the quality of output voltage waveforms, so they have attracted more and more attention. Taking the topology of Type-III asymmetric CHB multilevel inverters as the research object, a Modified Hybrid Frequency Pulse Width Modulation (MHF-PWM) strategy is proposed in this paper. This modulation strategy overcomes the local overshoot of low-voltage unit in the presence of traditional Hybrid Frequency Pulse Width Modulation (HF-PWM), thus completely eliminating the low frequency harmonics in the output voltage waveform of Type-III ACHB nine-level inverters, and the Total Harmonic Distortion (THD) of output line voltage of the modulation strategy is lower than that of PS-PWM strategy in the whole modulation degree, which effectively improves the quality waveform of the output line voltage. At the same time, the strategy can also improve the problems of current backflow and energy feedback caused by the high-voltage unit pouring current to the low-voltage unit, thereby reducing the imbalance of the output power of the high-voltage and low-voltage units. Finally, the Matlab/Simulink simulation model and experimental platform are established to verify the validity and practicality of the modulation strategy.

Designing of a High Voltage Power Supply for Electrospinning Apparatus Using a High Voltage Flyback Transformer (HVFBT)

2015 ◽  
Vol 771 ◽  
pp. 145-148 ◽  
Author(s):  
Muhammad Miftahul Munir ◽  
Dian Ahmad Hapidin ◽  
Khairurrijal
Keyword(s):  
High Voltage ◽  
Duty Cycle ◽  
Power Supply ◽  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Experimental Results ◽  
High Voltage Power Supply ◽  
Electrospinning Technique ◽  
The World

Research on nanofiber materials is actively done around the world today. Various types of nanofibers have been synthesized using an electrospinning technique. The most important component when synthesizing nanofibers using the electrospinning technique is a DC high voltage power supply. Some requirements must be fulfilled by the high voltage power supply, i.e., it must be adjustable and its output voltage reaches tens of kilovolts. This paper discusses the design and development of a high voltage power supply using a diode-split transformer (DST)-type high voltage flyback transformer (HVFBT). The DST HVFBT was chosen because of its simplicity, compactness, inexpensiveness, and easiness of finding it. A pulse-width modulation (PWM) circuit with controlling frequency and duty cycle was fed to the DST HVFBT. The high voltage power supply was characterized by the frequency and duty cycle dependences of its output voltage. Experimental results showed that the frequency and duty cycle affect the output voltage. The output voltage could be set from 1 to 18 kV by changing the duty cycle. Therefore, the nanofibers could be synthesized by employing the developed high voltage power supply.

Synchronized Symmetrical Bus-Clamping PWM Strategies for Three Level Inverter: Applications to Low Switching Frequencies

2011 ◽  
Vol 12 (2) ◽  
Author(s):  
Sreenivasappa Bhupasandra Veeranna ◽  
Udaykumar R Yaragatti ◽  
Abdul R Beig
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
High Performance ◽  
Pulse Width Modulation ◽  
Industrial Applications ◽  
Voltage Source ◽  
Switching Frequency ◽  
Space Vector ◽  
Digital Implementation ◽  
Switching Losses

The digital control of three-level voltage source inverter fed high power high performance ac drives has recently become a popular in industrial applications. In order to control such drives, the pulse width modulation algorithm needs to be implemented in the controller. In this paper, synchronized symmetrical bus-clamping pulse width modulation strategies are presented. These strategies have some practical advantages such as reduced average switching frequency, easy digital implementation, reduced switching losses and improved output voltage quality compared to conventional space vector pulse width modulation strategies. The operation of three level inverter in linear region is extended to overmodulation region. The performance is analyzed in terms THD and fundamental output voltage waveforms and is compared with conventional space vector PWM strategies and found that switching losses can be minimized using bus-clamping strategy compared to conventional space vector strategy. The proposed method is implemented using Motorola Power PC 8240 processor and verified on a constant v/f induction motor drive fed from IGBT based inverter.

scholarly journals Implementation of 5-Level H-Bridge Inverter with Multicarrier based Modulation Techniques

2020 ◽  
Vol 8 (5) ◽  
pp. 5180-5185
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Reference Signal ◽  
Low Frequency ◽  
Harmonic Spectrum ◽  
Multilevel Inverter ◽  
Modulation Method ◽  
Dc Voltage ◽  
Modulation Technique

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.

scholarly journals A REDUCED SWITCH THIRTEEN LEVEL INVERTER FOR PHOTOVOLTAIC APPLICATIONS

2021 ◽  
pp. 71-75
Author(s):  
Mr.A.VinothKumar ◽  
Dr.S.Vijayabaskar ◽  
Ms.C.Selsiya
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Power Converters ◽  
Renewable Energy Sources ◽  
Photovoltaic Applications ◽  
Multi Level ◽  
Photo Voltaic ◽  
Inverter Topology ◽  
Lower Voltage

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.

scholarly journals Algorithim to control output voltage and reduce the ripple of input current in quasi switched boost inverter

2021 ◽  
Vol 4 (2) ◽  
pp. first
Author(s):  
Xuan-Vinh Le ◽  
Duc-Minh Nguyen ◽  
Viet-Anh Truong ◽  
Thanh-Hai Quach
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Short Circuit ◽  
Modulation Index ◽  
Duty Ratio ◽  
Electrical Systems ◽  
Boost Factor ◽  
Control Output ◽  
Current Ripple

In recent years, the quasi -switched boost inverter uses widely in electrical systems. This paper proposes a method to control the AC output voltage and reduce the current ripple of the booster inductor in the quasi-switched boost inverter (QSBI). The proposed technique base on carrier pulse width modulation with two triangles with phase shifts 90◦. This technique uses the offset function to expand the modulation index and the algorithm for output voltage stabilization based on the adjustment of the boost ratio. The modulation index expansion will reduce the stress voltage on the switches by an average of 16.5% under the simulated conditions. The boost factor base on the short circuit time on the DC / DC booster and the inverter on the zero vectors. So, the duty ratio (of the boost DC / DC) can reduce by the short-circuit pulses that insert in the position of zero vectors, so the inverter is responsible for both boosting and inverting. The combination helps to reduce the current ripple on the boost inductor. Besides that, reducing the short-circuit ratio of DC / DC booster will also reduce the capacity of the booster switch and thereby reduce the production cost. The analysis clarifies the proposed technique. Simulations and experiments evaluate the proposed method.

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