Grid Impedance Estimation by Measuring only the Current Injected to the Grid by a VSI with LCL Filter

A strategy for grid impedance estimation is proposed in this article. The strategy is based on the use of an observer suitable to implement the control and synchronization of a voltage-source inverter with an LCL filter, by measuring only the current that the system injects to the grid. The estimation is done based on the modification of the original structure of the observer, together with the implementation of a grid current injection strategy, which allows the observer to adapt in the presence of grid impedance uncertainty. The proposed strategy provides an accurate estimate of the grid impedance inductive and resistive components, suitable for control purposes. The validity and effectiveness of the proposed strategy are demonstrated by simulation and experimental results.Fil: Fantino, Roberto Armin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentina. University of Arkansas; Estados UnidosFil: Busada, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Solsona, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentin

Optimum PR Control applied to LCL filters with Low Resonance Frequency

A control strategy for LCL Grid-connected voltage source inverters is proposed. Using the injected grid current measurement exclusively, the proposal allows the use of the proportional plus resonant regulator (PR) optimum design, regardless of the filter resonance frequency. Simulation and experimental results that demonstrate the validity and effectiveness of the proposal for different LCL filter resonance frequency values are presented. Also its superiority compared to a control methodrecently proposed in the literature is shown.Fil: Fantino, Roberto Armin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Busada, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Solsona, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentin

Nonlinear observer-based control for PMSG wind turbine

This paper introduces a mechanical sensorless control strategy to be used in variable speed wind energy conversion systems based on permanent magnet synchronous generators. The goal of the control strategy is to track the wind turbine maximum power point. With the proposed strategy, mechanical sensors are not needed to implement the control law. For this reason, electrical sensors -voltage and current sensors-are only needed to build the control law. In order to obtain estimates of the mechanical variables, a nonlinear Luenberger-like observer is designed. This observer only uses measurements of the electrical variables. The estimates are fed back to the controller in order to build the mechanical sensorless control strategy. The performance of the whole system is tested through simulations.Fil: Fantino, Roberto Armin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica ; ArgentinaFil: Solsona, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica ; ArgentinaFil: Busada, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica ; Argentin

Observer-Based Grid-Voltage Sensorless Synchronization and Control of a VSI-LCL Tied to an Unbalanced Grid

This paper proposes an observer-based grid-voltage sensorless strategy that allows to implement the synchronization and control of an LCL grid-tied voltage source inverter. By using exclusively the measurement of the current injected to the grid, an observer estimates both fundamental positive- and negative-sequence components of the grid voltage, with a quality (in terms of total harmonic distortion and convergence speed) comparable to that obtained with a classic double second-order generalized integrator-frequency-locked loop (DSOGI-FLL). The unmeasured LCL filter states are also estimated by the observer, and they are used to implement a full-state feedback control strategy suitable for low resonance frequency LCL filters. The effectiveness of the scheme proposed here is demonstrated by comparison with a DSOGI-FLL and with a controller recently proposed in the literature. Experimental and simulation results that demonstrate the validity and effectiveness of the proposal are presented.Fil: Fantino, Roberto Armin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Busada, Claudio A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Solsona, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentin

Inductor Encapsulation-Based Thermal Management Enabling Increased Power Density

Inductors occupy significant volume in dc-dc converters where power density is an important figure of merit. This research work addresses an improved design of a power-dense nanocrystalline-based inductor employing potting materials with high thermal conductivity. Contrary to traditional inductor design methods which require larger volumes to accommodate for temperature rise limits, this work presents an analytical framework to decrease the inductor volume through encapsulation. Particularly, it analyzes the effectiveness of employing a hybrid potting material, through experimental investigation of various filler compositions as compared to the classical silicone gel-based materials. Experimental evidence verifying the theoretically designed method is presented in this work.Fil: Christian, Shamar. University of Arkansas for Medical Sciences; Estados UnidosFil: Fantino, Roberto Armin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Amir Gomez, Roderick. University of Arkansas for Medical Sciences; Estados UnidosFil: Balda, Juan Carlos. University of Arkansas for Medical Sciences; Estados Unidos13th International Symposium on Power Electronics for Distributed Generation SystemsKielAlemaniaInstitute of Electrical and Electronics Engineer

Etching Process to Reduce Interlamination Short Circuits and Core Loss Comparison for Tape-Wound Cut Cores

Soft-magnetic ribbon-based materials have been gaining popularity as their properties yield better efficiencies and power densities. Nevertheless, magnetic designs with these materials present a major shortcoming in the manufacturing process of tape-wound cut cores. Thus, this paper focuses on the critical issue of ribbon-based soft-magnetic cut-cores due to short-circuited layers along the cross-sectional area resulting from the cutting process. An etching process is proposed to overcome the interlamination short circuits of the magnetic cores. A microscopic view of the cross-sectional area demonstrates the effectiveness of the etching process. Furthermore, two identical experimental medium-frequency transformers are built to study and compare the effects of the core etching on the transformer parameters. Open- and short-circuit impedance responses, and core loss characterization over frequency and flux density are presented before and after the etching process to establish the proper process to handle these tape-wound cut cores.Fil: Gomez, Roderick A.. University of Arkansas for Medical Sciences; Estados UnidosFil: Christian, Shamar F.. University of Arkansas for Medical Sciences; Estados UnidosFil: Oggier, Germán G.. Universidad Nacional de Río Cuarto; ArgentinaFil: Fantino, Roberto Armin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Balda, Juan C.. University of Arkansas for Medical Sciences; Estados UnidosFil: Zhao, Yue. University of Arkansas for Medical Sciences; Estados Unidos13th International Symposium on Power Electronics for Distributed Generation SystemsKielAlemaniaInstitute of Electrical and Electronics Engineer

A 150-kW 99% Efficient All-Silicon-Carbide Triple-Active-Bridge Converter for Solar-Plus-Storage Systems

Solar-plus-storage systems could effectively mitigate the uncertainties of the photovoltaic (PV) generation and improve system reliability by adding an integrated battery energy storage system. As a three-port bidirectional isolated dc-dc converter with soft-switching capability, the triple-active-bridge (TAB) converter inherently matches the requirements of the solar-plus-storage system. However, challenges still remain in the TAB converter design to further improve system efficiency. In this article, the detailed design, implementation, and demonstration for a silicon carbide (SiC) 150-kW TAB converter are presented. Starting from a brief review of the TAB converter, the modulation scheme, power characteristics, and soft-switching region are analyzed. Then, the detailed design of the H-bridge converter building block is given. To improve the system efficiency, a comprehensive characterization of the SiC gate driver with various external gate resistances is performed to address tradeoffs between switching loss and voltage overshoot during transients, as well as the thermal performance of the H-bridge building block. In addition, the design and characterization of the 20-kHz three-port transformer are also given. Comprehensive experimental studies are conducted on a full-power prototype to verify the proposed design. With a measured 99.1% peak efficiency, the proposed TAB converter can fulfill the requirements for solar-plus-storage applications.Fil: Wu, Yuheng. University of Arkansas; ArgentinaFil: Mahmud, Mohammad Hazzaz. University of Arkansas; ArgentinaFil: Christian, Shamar. University of Arkansas; ArgentinaFil: Fantino, Roberto Armin. University of Arkansas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gomez, Roderick Amir. University of Arkansas; ArgentinaFil: Zhao, Yue. University of Arkansas; ArgentinaFil: Balda, Juan Carlos. University of Arkansas; Argentin