FREQUENCY CONVERTER WITH THE REDUCED THD OF THE OUTPUT VOLTAGE

2016 ◽  
Vol 2016 (5) ◽  
pp. 14-16 ◽  
Author(s):  
G.V. Pavlov ◽  
◽  
I.L. Vinnichenko ◽  
A.V. Obrubov ◽  
◽  
...  
Keyword(s):  
Output Voltage ◽  
Frequency Converter

scholarly journals A method for calculating the parameters of the sine filter of the frequency converter, taking into account the criterion of starting current limitation and pulse-width modulation frequency

2021 ◽  
Vol 1 (8 (109)) ◽  
pp. 6-16
Author(s):  
Volodymyr Nerubatskyi ◽  
Oleksandr Plakhtii ◽  
Denys Hordiienko ◽  
Serhii Mykhalkiv ◽  
Vasyl Ravluyk
Keyword(s):  
Power Generation ◽  
Output Voltage ◽  
Modulation Frequency ◽  
Frequency Converter ◽  
Harmonic Distortion ◽  
Voltage Inverter ◽  
Starting Current ◽  
Lc Filter ◽  
Power Generation Systems ◽  
Filter Capacitor

An analysis of the method for ensuring the sinusoidality of the output voltage in power generation systems with self-commutated voltage inverters under the requirements of the international standard IEEE-519 is presented. In a number of programs, especially low-power generation systems, a low-cost solution is needed to provide the sinusoidal waveform of the output voltage with the total harmonic distortion of 5 %. This solution is to use two-level voltage inverters with an output sine LC filter. However, the feature of the sine filter with the frequency converter is that the PWM frequency affects the spectrum of higher harmonics of the output voltage. In addition, there is the starting current of the filter capacitor, which can disable the power switches of the voltage inverter. The developed method for calculating the values of the LC filter with the two-level voltage inverter in the PWM mode is presented meeting the requirements of the international standard IEEE-519, taking into account the modulation frequency and limitation of the starting current of the filter capacitor. To confirm the required quality of the output voltage of the two-level voltage inverter with the sine filter, an appropriate simulation model was created in the Matlab/Simulink computer simulation environment. The oscillograms and harmonic analysis of the input and output voltages of the sine filter, which showed the total harmonic distortion of 1.88 %, are presented. A physical prototype of the investigated system was created on the basis of a 5.5 kW OVEN PChV203-5K5-V frequency converter (Ukraine). Using the SIGLENT SDS1104X-E oscilloscope (China), the real waveform and the results of the harmonic analysis of the sine filter output voltage, confirming the implementation of the necessary sinusoidality criteria, were obtained

scholarly journals Troubleshooting of Matrix Frequency Converter Conducted and Radiated Emissions

2010 ◽  
Vol 27 (1) ◽  
pp. 146-151
Author(s):  
Gundars Asmanis ◽  
Leonids Ribickis ◽  
Vladimirs Novikovs
Keyword(s):  
Output Voltage ◽  
Electromagnetic Compatibility ◽  
Low Cost ◽  
Frequency Converter ◽  
Matrix Converter ◽  
Point Of View ◽  
Standard Equipment ◽  
Sinusoidal Input ◽  
Radiated Emissions ◽  
Electronics And Electrical

Troubleshooting of Matrix Frequency Converter Conducted and Radiated EmissionsMatrix converter inherently exhibits sinusoidal input current waveforms and has less stressful output voltage waveforms, but it is causing problems with conducted and radiated emissions. This paper deals with matrix converter emitted disturbances from point of view of electromagnetic compatibility (EMC) standard EN61800-3 and allocates the sources of undesirable emissions using standard equipment used for EMC assessment according to variety international EMC standards and discusses methodology of troubleshooting flow, using low cost equipment available in almost every laboratory of Industrial Electronics and Electrical Engineering.

scholarly journals Universal power converter for low power applications

2019 ◽  
Vol 10 (4) ◽  
pp. 2165
Author(s):  
M. Asna ◽  
H. Shareef ◽  
S. N. Khalid ◽  
A. O. Idris ◽  
A. N. Aldarmaki ◽  
...  
Keyword(s):  
Reference Frame ◽  
Output Voltage ◽  
Frequency Conversion ◽  
Search Algorithm ◽  
Frequency Converter ◽  
Optimization Technique ◽  
Power Converter ◽  
Experimental Result ◽  
Synchronous Reference Frame ◽  
Parameter Values

A novel power converter that can perform both voltage and frequency conversion was proposed. Inappropriate power supply can damage sensitive sub-components and render the connected device inoperable. Henceforth, the proposed voltage–frequency converter acts as an interface to plug any electrical device directly into an electrical socket and provide the voltage and frequency required. The converter used a synchronous reference frame proportional–integral (SRFPI) controller to regulate the instantaneous output voltage and to improve steady state performance. Because the PI controller works together with the synchronous reference frame controller, it is difficult to tune the PI control parameters. To overcome this issue, a new meta heuristic optimization technique called lightening search algorithm (LSA) optimization was used to identify the optimum PI parameter values. A detailed description of the system operation and control strategy was presented. Finally, the performance of the converter was analyzed and verified by simulation and experimental results. The experimental result has shown that the proposed system has satisfactory output voltage and frequency under different input voltages.

scholarly journals Electric Propulsion system on the basis of the matrix direct frequency converter

2015 ◽  
Vol 7 (2) ◽  
Author(s):  
Evgenij Koptjaev ◽  
Roman Evseev ◽  
Vyacheslav Balashevich
Keyword(s):  
Electric Propulsion ◽  
Output Voltage ◽  
Frequency Converter ◽  
Asynchronous Motor ◽  
Propulsion System ◽  
Mode Switching ◽  
Natural Mode ◽  
Propulsion Systems ◽  
Electric Propulsion System ◽  
Soft Start

Many of today's ships are equipped with electric propulsion systems, which leads to the relevance of the article. The general trend is the use of electric propulsion systems AC, due to a more robust design of an asynchronous motor and slightly better weight and dimensions. The use of asynchronous motor requires a static frequency converter for speed control and soft start. In the currently used PWM converters different types. Opportunities classical direct frequency converters are limited due to a number of fundamental shortcomings, particularly the lack of quality of the output voltage and the presence of the gap current during switching. Offered in Article electric propulsion system with direct frequency converter allows for a natural mode switching valves, as well as significantly improve the harmonic composition of output voltage and current of the inverter. The absence of a carrier frequency pulse-width modulation improves acoustics and electromagnetic compatibility with the ship's equipment. Mode powered by two independent generators improves vibro-acoustic characteristics.

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 Correction of the static characteristic of a frequency converter to reduce the amplitudes of resonance vibrations of the vibrating table

2021 ◽  
Vol 29 (2) ◽  
pp. 117-128
Author(s):  
Alexander S. Vedernikov ◽  
Dmitry I. Dunaev
Keyword(s):  
Output Voltage ◽  
Frequency Control ◽  
Frequency Converter ◽  
Equations Of Motion ◽  
Effective Means ◽  
Control Object ◽  
Static Characteristic ◽  
Static Characteristics ◽  
Acceleration And Deceleration ◽  
Vibrating Table

It is known that vibration systems of directional vibrations based on asynchronous vibration motors are currently widely used in practice, but at the same time they have a significant drawback - a sharp increase in vibration amplitudes when passing through the resonance zone at the time of acceleration and deceleration of vibration motors, which negatively affects their operation. The article discusses a vibration table with two unbalanced asynchronous vibration motors. The calculation scheme and equations of motion of such a vibration system are presented. It is shown that the vibration table as a control object is an oscillatory link with a pronounced resonant frequency. The equations of motion of asynchronous vibration motors with scalar frequency control are given. A structural diagram of a vibration table with unbalanced exciters has been developed, the modeling of which made it possible to determine the amplitudes of resonant oscillations. It is proposed to apply correction of the static characteristics of the frequency converter, which connects the effective value of the output voltage with the frequency, to reduce the resonance amplitudes. Equations of the desired static characteristics of the inverter and analytical dependences for calculating the necessary coefficients for its implementation are given. A computational model has been developed that makes it possible to take into account the effect of the corrected static characteristic of the frequency converter on the operation of the vibrating table at the stages of acceleration and deceleration. The results of computer simulation are given, convincingly showing that the correction of the static characteristics of the inverter is an effective means of reducing the amplitudes of resonant oscillations. It is shown that modern frequency converters have functionality that makes it easy to correct the dependence of the effective value of the output voltage on the frequency. The need to adjust the static characteristics of the inverter for a specific type of product tested on the vibration table is noted.

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.

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