The Experts below are selected from a list of 14763 Experts worldwide ranked by ideXlab platform
Immanuel Selwynraj A - One of the best experts on this subject based on the ideXlab platform.
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Sliding mode controller-based voltage source inverter for power quality improvement in microgrid
IET Renewable Power Generation, 2020Co-Authors: Vinifa Rajakumar, Kavitha Anbukumar, Immanuel Selwynraj AAbstract:Development of control technologies facilitates the integration of renewable energy sources to the grid through power electronic converters. In this study, the inverter acts as shunt active power filter along with the power conversion operation. Various sliding mode control (SMC) techniques namely relay and signum method, hysteresis method and Equivalent control method are implemented to control the real, and reactive power flow between Renewable Energy System (RES), load and grid using an inverter. To reduce the complexity, the control law (u eq) for Equivalent control method is derived using a simple Single-Phase Equivalent Circuit of a three-phase voltage source inverter. In this study, the robustness is enhanced by choosing the integral sliding surface. These controllers are used to reduce the total harmonic distortion (THD) and to ensure unity power factor (PF) in the grid during balanced and unbalanced grid voltage conditions even in the existence of nonlinear loads. The SMC using Equivalent control function outperforms the other methods in terms of chattering, THD and PF. To illustrate the effectiveness, three different modes are considered: (i) no RES power, (ii) insufficient RES power and (iii) excess RES power. The performance of controllers is validated by the simulation and experimental results.
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Power Quality Enhancement Using Lyapunov Based Voltage Source Inverter for the Grid Integrated Renewable Energy System
International Journal of Emerging Electric Power Systems, 2019Co-Authors: Vinifa R, Kavitha A, Immanuel Selwynraj AAbstract:Abstract The evolution of high performance power electronic converters makes a feasible way to integrate the Renewable Energy System (RES) to the grid. High performance in terms of stability, good transient and steady state response, load variations is achieved in this work using Current Controlled Voltage Source Inverters (CCVSI) by deriving the control law using Lyapunov function at the expense of a time varying reference current. In this work, a single phase Equivalent Circuit is represented for the three phase grid connected renewable energy system, and mathematical modeling is developed to design the controller. Analysis using Lyapunov based controller is carried out to ensure the real and reactive power flow from the renewable energy system to the grid connected with the non linear load. The reference current for the controller is generated using the Symmetrical Component theory. This theory requires no transformation and desired source power factor can be achieved. To exhibit the efficacy of the Lyapunov controller, the simulation is carried out using MATLAB/Simulink environment. It is observed that the desired power factor is obtained and Total Harmonic Distortion (THD) is within the IEEE limits in the grid side. The performance of the system is validated experimentally and the results are compared with the conventional hysteresis controller for the same application.
Christian Rehtanz - One of the best experts on this subject based on the ideXlab platform.
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An Inductively Filtered Multiwinding Rectifier Transformer and Its Application in Industrial DC Power Supply System
IEEE Transactions on Industrial Electronics, 2016Co-Authors: Yong Li, Yi Jia Cao, Wenye Liu, Guandong Zhou, Fanghong Yao, Longfu Luo, Sijia Hu, Zhiwen Zhang, Fang Liu, Christian RehtanzAbstract:In this paper, a new industrial direct-current (dc) power supply system with the four-winding inductively filtered rectifier transformer (FW-IFRT) is proposed based on an inductive filtering (IF) method, which can effectively solve the power quality problems generally existing in the high-power rectifier system, such as high energy consumption, serious harmonic pollution, low power factor, and so on. The Single-Phase Equivalent Circuit model of such a new system is established based on the multiwinding transformer theory, and then its operating characteristics are investigated in detail. The harmonic suppression factor is proposed, and the influences of system and transformer impedances on the harmonic suppression characteristic are revealed. Finally, the simulation and experimental case studies are used to verify the effectiveness of the proposed system on the comprehensive improvement of power quality and operating efficiency.
Lucas Frizera Encarnacao - One of the best experts on this subject based on the ideXlab platform.
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Open-Loop Single-Phase Space State Model and Equivalent Circuit of a Non-Conventional Three-Phase Inverter
Electronics, 2020Co-Authors: Vinícius Melo, Alexandre Melo, Walbermark Santos, Jussara Farias Fardin, Lucas Frizera EncarnacaoAbstract:Recently, many non-conventional three-phase inverters, topologies for green energy source grid-connection systems, and electric drives have been proposed. Simplifying the inverter Circuit is crucial to analyze and solve their models in order to design them. The main goal of the study is centered on obtaining a Single-Phase Equivalent Circuit and space state model from non-conventional three-phase inverters based on bidirectional direct current–direct current (DC–DC) Buck-Boost topology using isolated gate bipolar transistors (IGBT). From just one phase of the three-phase inverter, the Single-Phase Equivalent Circuit was obtained by means of Kirchhoff’s laws. The Equivalent Circuit operation steps were presented in order to obtain the space state model. Finally, the Equivalent Circuit was simulated, and experimental results with a 200 W three-phase inverter feeding a resistive, inductive, and capacitive loads were performed to confirm the theoretical and simulation analyses. The results show the state space dynamic behavior variables of Single-Phase and three-phase models are quite similar. Therefore, it can be concluded that the proposed Circuit can be used with property to represent Equivalent Single-Phase models of non-conventional three-phase inverters.
Man-chung Wong - One of the best experts on this subject based on the ideXlab platform.
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A Deadbeat Current Controller of LC -Hybrid Active Power Filter for Power Quality Improvement
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020Co-Authors: Wai-kit Sou, Wai-hei Choi, Chi-wa Chao, Chi-seng Lam, Cheng Gong, Chi-kong Wong, Man-chung WongAbstract:In this article, a deadbeat current controller for an LC -coupling hybrid active power filter ( LC -HAPF) is proposed, which can track with the reference compensation current with low steady-state error and fast dynamic response. Moreover, it can lead LC -HAPF to be operating at a fixed switching frequency with low output current ripples, thus reducing the size of the filtering Circuit. First of all, the mathematical model of the deadbeat current controller for the LC -HAPF is deduced based on its Single-Phase Equivalent Circuit. Then, the closed-loop control block diagram and its $s$ -domain model is proposed and built. After that, the stability issue and parameter design of the proposed deadbeat current controller are analyzed and discussed. Finally, the compensating performance of the deadbeat current controller for the LC -HAPF is verified by simulation and experimental results compared with the conventional hysteresis band pulsewidth modulation (PWM) control, the proportional-integral (PI) control, and the proportional multi-resonant (PMR) control for the LC -HAPF, which shows its effectiveness and superior compensating performances.
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Minimum DC-link voltage design of three-phase four-wire active power filters
2012 IEEE 13th Workshop on Control and Modeling for Power Electronics (COMPEL), 2012Co-Authors: Man-chung WongAbstract:This paper presents a minimum dc-link voltage design for three-phase four-wire center-split active power filters (APFs). According to the current quality data and the APF Single-Phase Equivalent Circuit models, the minimum dc-link voltage expression for the APF is deduced and proposed, in which the deduced expression is applicable to Single-Phase and three-phase four-wire APF systems. Representative simulation results of the three-phase four-wire APF are presented to verify the minimum dc-link voltage expression.
L Moran - One of the best experts on this subject based on the ideXlab platform.
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voltage source active power filter based on multilevel converter and ultracapacitor dc link
IEEE Transactions on Industrial Electronics, 2006Co-Authors: M Ortuzar, R Carmi, J Dixon, L MoranAbstract:A new topology for active power filters (APF) using an 81-level converter is analyzed. Each phase of the converter is composed of four three-state converters, all of them connected to the same capacitor dc link voltage and their output connected in series through output transformers. The main advantages of this kind of converter are the negligible harmonic distortion obtained and the very low switching frequency operation. The Single-Phase Equivalent Circuit is analyzed and their governing equations derived. The dc link voltage control, based on manipulating the converter's voltage phase, is analyzed together with the Circuit's characteristics that determine the capability to draw or deliver active and reactive current. Simulation results for this application are compared with conventional pulsewidth-modulated (PWM) converters, showing that this filter can compensate load current harmonics, keeping better-quality sinusoidal currents from the source. The simulated configuration uses a 1-F ultracapacitor in the dc link, making it possible to store energy and deliver it during short voltage dips. This is achieved by applying a modulation control to maintain a stable ac voltage during dc voltage drops. A prototype of the filter was implemented and tested, and the obtained current waveforms showed to be as good as expected.
