scholarly journals Mitigation of DC Components Using Adaptive BP-PID Control in Transformless Three-Phase Grid-Connected Inverters

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2047 ◽  
Author(s):  
Long Bo ◽  
Lijun Huang ◽  
Yufei Dai ◽  
Youliang Lu ◽  
Kil To Chong
Keyword(s):  
Pid Control ◽  
Pulse Width Modulation ◽  
High Efficiency ◽  
Back Propagation ◽  
Power Transistors ◽  
Three Phase ◽  
The Subject ◽  
Dc Component ◽  
Driving Signal

Transformerless grid-connected inverters, due to their advantages of high efficiency, small volume and light weight, have been the subject of more research and interest in recent years. Due to the asymmetrical driving signal in pulse width modulation (PWM) caused by time-delay, zero-drift of the current sensors and imparities of the power transistors, output of the grid current contains dc component. As a result, power quality of the grid is degraded. In this paper, a dc (direct current) component suppression scheme with adaptive back-propagation (BP) neural network proportional-integral-differential (PID) control is proposed for dc component minimization. Moreover, sliding-window-double-iteration-method (SWDIM) is utilized for fast dc component extraction. Compared with the conventional method, the proposed scheme shows better performance, and the dc component can be attenuated to be within 0.5% of the rated current.

Performance Improvement of SVPWM-Based Three-Phase Grid-Connected Inverters

2013 ◽  
Vol 732-733 ◽  
pp. 1261-1264
Author(s):  
Zhi Lei Yao ◽  
Lan Xiao ◽  
Jing Xu
Keyword(s):  
Dynamic Response ◽  
Control Strategy ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Grid Current ◽  
Current Controller ◽  
Three Phase ◽  
Reference Grid ◽  
Grid Connected Inverter

An improved control strategy for three-phase grid-connected inverters with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d-and q-axes grid currents is interacted in the traditional control method, and the waveform quality of the grid current is poor. As the reference output voltage cannot directly reflect the change of the reference grid current with the traditional control strategy, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d-and q-axes grid currents in the decoupled components of the grid current controller are substituted by the d-and q-axes reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results show that the grid-connected inverter with the improved control strategy has high waveform quality of the grid current and fast dynamic response.

scholarly journals A Genetic-Algorithm-Based DC Current Minimization Scheme for Transformless Grid-Connected Photovoltaic Inverters

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 746 ◽  
Author(s):  
Lei Song ◽  
Lijun Huang ◽  
Bo Long ◽  
Fusheng Li
Keyword(s):  
Genetic Algorithm ◽  
Back Propagation ◽  
The Novel ◽  
Proof Of Concept ◽  
Three Phase ◽  
Suppression Process ◽  
Dc Current ◽  
Three Phase Inverter ◽  
Minimization Scheme

Transformerless grid-connected inverters are of great industrial value in photovoltaic power generation. However, the direct current (DC) induced into the inverter’s output degrades the power quality of the grid. Recently, a back-propagation neural work proportional–integral–derivative (BP-PID) scheme has proven helpful in solving this problem. However, this scheme can be improved by reducing the suppressing time and overshoot. A genetic algorithm (GA)-based DC current minimization scheme, namely the genetic-algorithm-based BP-PID (GA-BP-PID) scheme, was established in this study. In this scheme, GA was used off-line to optimize the initial weights within the BP neural network. Subsequently, the optimal weight was applied to the online DC current suppression process. Compared with the BP-PID scheme, the proposed scheme can reduce the suppressing time by 59% and restrain the overshoot. A prototype of the proposed scheme was implemented and tested on experimental hardware as a proof of concept. The results of the scheme were verified using a three-phase inverter experiment. The novel GA-PB-PID scheme proposed in this study was proven efficient in reducing the suppressing time and overshoot.

scholarly journals Modelling of three phase SVPWM AC-AC converter using unity power factor control

2019 ◽  
Vol 10 (4) ◽  
pp. 1823
Author(s):  
Saidah Saidah ◽  
Hari Sutiksno ◽  
Bambang Purwahyudi ◽  
Taufik Taufik
Keyword(s):  
Power Factor ◽  
Pulse Width Modulation ◽  
High Efficiency ◽  
Input Voltage ◽  
Input Power ◽  
Current Waveform ◽  
Unity Power Factor ◽  
Dc Voltage ◽  
Three Phase ◽  
Power Factor Control

This paper introduces the modelling of a novel three phase AC-AC converter with indirect use of a capacitor as DC voltage link. The proposed converter has high efficiency because it uses Space Vector PWM (SVPWM) technique at both rectificier and inverter stages to operate the pulse width modulation in IGBT switches. The novel converter is equipped with a power factor control to shape the rectifier input current waveform to be sinusoidal and to be in phase with the input voltage. To keep the DC voltage stable, the converter utilizes PI controllers. Simulations are conducted for output voltage from 120 to 300 Volts with output frequency ranging from 30 Hz to 60 Hz. The simulation results show that the converter is able to maintain stable the DC voltage and current. Furthermore, the model demonstrates the benefits of proposed converter in terms of acquiring high input power factor and sinusoidal current waveform at the output side of the inverter.

scholarly journals Modelling of a Two-Stage Bidirectional AC-DC Converter using Wavelet Modulation

2018 ◽  
Vol 9 (3) ◽  
pp. 1006
Author(s):  
H.K. Chiu ◽  
Agileswari K. Ramasamy ◽  
Nadia M.L. Tan ◽  
Matthew Y.W. Teow
Keyword(s):  
Power Flow ◽  
High Efficiency ◽  
Harmonic Distortion ◽  
Two Stage ◽  
Bidirectional Converter ◽  
Three Phase ◽  
Dc Component ◽  
And Performance ◽  
Bidirectional Power Flow ◽  
Ev Charging

<span lang="EN-US">In this paper, a Wavelet modulated isolated two-stage three-phase bidirectional AC-DC converter is proposed for electric vehicle (EV) charging systems. Half-bridge resonant CLLC converter is proposed due to its high efficiency, wide gain range, galvanic isolation and bidirectional power flow. Wavelet modulation technique is used for three-phase six leg AC-DC converter due to its benefits of high DC component and lower harmonic contents. The proposed two-stage converter is developed and simulated in MATLAB Simulink environment. The contribution of this paper is on the implementation and performance analysis of Wavelet modulation in bidirectional AC-DC converters. The results show that Wavelet modulation is suitable to be implemented for the proposed bidirectional converter. The performance of the proposed converter delivers very low output voltage ripple and total harmonic distortion output current of less than 10% which is within the expected results.</span>

scholarly journals Design of a New Duty Cycle Modulation to Improve the Energy Quality of an Insulated Production System

2021 ◽  
Vol 23 (4) ◽  
pp. 311-319
Author(s):  
Clément Kengnou Donfack ◽  
Charles Hubert Kom ◽  
Jean Jacques Mandeng ◽  
Félix Paune
Keyword(s):  
Duty Cycle ◽  
Pulse Width Modulation ◽  
Renewable Energy Sources ◽  
Control Technique ◽  
Three Phase ◽  
New Strategy ◽  
The One ◽  
Sinusoidal Pulse Width Modulation ◽  
Three Phase Inverter

In this article, we propose a new strategy for controlling three-phase inverters of renewable energy sources, based on the Duty Cycle Modulatiom (DCM) control using the Park and Fortescue transformation (DCM-dq-dih). Our goals in setting and using this strategy are, on the one hand, to induce a lower harmonic rate as compared to the SPWM (Sinusoidal Pulse Width Modulation) strategy and on the other hand, this control technique enables the inverter to deliver balanced voltages, be it in the event of load unbalance. Our design is built on the basis of the known mode of DCM control of single-phase inverters. Thus, the control of our three-phase inverter is carried out by three DCM modules whose set-points come from the direct, reverse and homopolar strings reconstructed in a Park landmark. This new strategy was tested on the MATLAB Simulink environment for a load of 160 kW. The test results show a reduced Total Harmonic Distorsion (THD) of 2.7 times compared to the THD produced by the SPWM control strategy. In addition, regulation of the symmetrical components during load unbalance is ensured so that the inverter always delivers constant and balanced voltages.

scholarly journals Análisis de la calidad de energía eléctrica en una subestación de 300 kVA

2019 ◽  
pp. 12-20
Author(s):  
Guillermo Miguel Martínez-Rodríguez ◽  
Berenice de Jesús Cruz-Isidro ◽  
Javier Garrido-Melendez ◽  
Jesús Jiménez-Rivera
Keyword(s):  
Electrical Parameter ◽  
Electrical Energy ◽  
International Standards ◽  
Measurement Equipment ◽  
Electrical Parameters ◽  
Three Phase ◽  
The Subject ◽  
Low Tension

In this research are presented the results of the measurements of the electrical parameters obtained by the three phase analyzer of electrical energy, there was used a methodology based on the own manual of the analyzer equipment, well as the national and international standards as well the IEEE Institute, the CFE company, and books of the subject, in which are stablished the limits and requirements for a good quality of the electrical energy necessary for the user of the electrical service. The contribution covers from the conection of the entry of the analyzer equipment until the instalation to the exit of low tension in the transformer, verifying in the equipment the vectorial diagrams and senoidals for corroborate that their conection be adequate, also were considered the measurements of the security in the instalation of the measurement equipment, throughout the document are mentioned the characteristics and the interpretation of each electrical parameter analyzed.

scholarly journals Microgrids Power Quality Enhancement Using Model Predictive Control

2021 ◽  
Author(s):  
Félix Garcia-Torres ◽  
Sergio Vazquez ◽  
Isabel Moreno-Garcia ◽  
Aurora Gil-de-Castro ◽  
Pedro Roncero-Sánchez ◽  
...  
Keyword(s):  
Model Predictive Control ◽  
Power Quality ◽  
Predictive Control ◽  
Control Algorithm ◽  
Pulse Width Modulation ◽  
Phase Voltage ◽  
Optimal Behavior ◽  
Three Phase ◽  
Current Systems

In this paper, the power quality of interconnected microgrids is managed using a Model Predictive Control (MPC) methodology which manipulates the power converters of the microgrids in order to achieve the requirements. The control algorithm is developed for the microgrids working modes: grid-connected, islanded and interconnected. The results and simulations are also applied to the transition between the different working modes. In order to show the potential of the control algorithm, a comparison study is carried out with classical Proportional-Integral Pulse Width Modulation (PI-PWM) based controllers. The proposed control algorithm not only improves the transient response in comparison with classical methods but also shows an optimal behavior in all the working modes, minimizing the harmonics content in current and voltage even with the presence of non-balanced and non-harmonic-free three-phase voltage and current systems

scholarly journals A three-phase inverter with selectively programmed pulse width modulation for an electric vehicle with battery supply

1987 ◽  
Vol 6 (1) ◽  
pp. 19-26
Author(s):  
L. Van der Merwe ◽  
J. D. Van Wyk
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Battery Voltage ◽  
Power Transistors ◽  
Hydraulic Hybrid ◽  
Squirrel Cage ◽  
Three Phase ◽  
Power Switches ◽  
And Control ◽  
Three Phase Inverter

The development and evaluation of a 15 kVA inverter with 144 V battery voltage and pulse width modulation for an electric-hydraulic hybrid road vehicle are discussed. The vehicle is equipped with a squirrel cage induction traction machine. This article covers the configuration of the inverter, the use of integrated bipolar Darlington power transistors, protection of the power switches, base drive of the transistors and control of the inverter. The inverter and drive energy efficiency are evaluated, and the installation of the inverter in the vehicle is discussed.

Measuring Service Quality in The Context of Higher Education in Vietnam

2013 ◽  
pp. 77-90
Author(s):  
Yen Nguyen Thi Hoang
Keyword(s):  
Higher Education ◽  
Service Quality ◽  
Exploratory Study ◽  
Measurement Scale ◽  
Education Service ◽  
The Subject

This paper focuses on the understanding of service quality in the context of Vietnamese universities. It proposes an approach for measuring the quality of the higher education service provided by universities in Vietnam. Firstly, an exploratory study was conducted. Then, the set of items which were generated became the subject of a questionnaire that was then administered to 675 students of a Vietnamese university to determine the dimensions of higher education service quality in this context. The obtained results permit us to appropriate a measurement scale which is slightly different from the SERVQUAL scale widely known as the standard for measuring service quality. The results also show that tangible elements, responsiveness and assurance seem to be three specific dimensions of the higher education service of Vietnamese universities.

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