4,038 research outputs found
Global goals for a better and more sustainable world demanding electrification and power electronics
Full text linkEn este número de In Genium dedicado a los Objetivos de Desarrollo Sostenibles (ODS) definidos por la ONU, desde la Sección de Ing. Eléctrica, Electrónica e Informática, invitamos al Prof. Frede Blaabjerg, de la Universidad de Aalborg en Dinamarca, a escribir un artículo para la revista. El Prof. Blaabjerg ha trabajado por más de 30 años en temas de Electrónica de Potencia aplicada a sistemas de energía y accedió gentilmente a escribir un artículo especial para In-Genium.Academia de la Ingeniería de la provincia de Buenos Aire
Virtual inertia operation of renewables
No full textThe synchronous rotating inertia is the key parameter of power system stability. Increasing the penetration of nonsynchronous generators, e.g., wind turbine, photovoltaics, and energy storage system, in the power grids leads to some stability challenges due to the lack of rotating mass and kinetic inertia in the system. In this chapter, the effect of high penetration of renewables on power system stability is shown. Moreover, the recent low-inertia grid challenges in Europe and South Australia are presented. Technically, in order to achieve 100% renewables, providing virtual inertia is a demand. The virtual synchronous machine (VSM) is a promising solution to emulate the behavior of a synchronous machine and provide inertia virtually. In this chapter, the theoretical concept of VSM, as well as the control structure, is also presented. Furthermore, the VSM implementation in the power system is explained, and some RMS simulation results are provided in a fault situation. Since in a controller based on the swing equation, the current is not controlled in the short time frame directly, a current limitation controller is also implemented in VSM and scrutinized in this chapter.</p
High switching frequency three-phase current-source converters and their control
No full textHigh switching frequency (current source converters) CSCs are increasingly concerned for improving the power efficiency and power density in many new applications. This chapter discusses the stability and control of high switching frequency CSCs. By involving the DC-link dynamics, stability of single-loop DC-link current control and design of three active damping methods are presented.</p
Single-Phase Induction Motor and AC Drives
No full textThis chapter presents the working principle and modeling of the single-phase induction motor (SPIM), as well as the control strategies of the SPIM with several different power electronics device-based variable frequency AC drives. The SPIM has been widely used for the water pumps, compressors, and fans with no tough demand for high performance and they are especially used at small-rated power below 1 kW. Besides the conventional single-phase main power supply, the SPIM can also be supplied by a single-phase or three-phase voltage source inverter. This chapter will first introduce the working principle of the SPIM, and then establish the modeling of the motor. Thereafter, this chapter will present theoretical analysis on how the SPIM performance is influenced by different supply methods, i.e., including the supply methods using a single-phase inverter with a running capacitor, or using a three-phase inverter with/without a running capacitor. Further comparisons will be made in terms of starting torque, starting current, pulsation torque, efficiency, etc. Simulation results are provided to compare and demonstrate the similarities and differences between these power electronics device-based variable frequency AC drives for SPIM
Phase-locked loops and their design
No full textThis chapter provides a comprehensive overview of the recent attempts for designing of the advanced three-phase and single-phase phase-locked loops (PLLs). The operating principle of both three-phase and single-phase PLLs is explained. Furthermore, the different features and applications of the PLLs are carefully discussed. Finally, the performance comparison guidance is provided and that could be a quick reference for proper selections of appropriate PLLs for researchers and engineers.</p
Overview of Single-Phase Grid-Connected Photovoltaic Systems
No full textA continuous booming installation of solar photovoltaic (PV) systems has been witnessed worldwide. It is mainly driven by the imperative demand of “clean” power generation from renewables. Grid-connected PV systems will thus become an even more active player in the future mixed power systems, which are linked together by a vast of power electronics converters and the power grid. In order to achieve a reliable and efficient power generation from PV systems, more stringent demands have been imposed on the entire PV system. It, in return, advances the development of the power converter technology in PV systems. This chapter thus gives an overview of the advancement of power electronics converters in single-phase grid-connected PV systems, being commonly used in residential applications. Demands to single-phase grid-connected PV systems and the general control strategies are also addressed in this chapter
Operating and Loading Conditions of a Three-Level Neutral-Point-Clamped Wind Power Converter Under Various Grid Faults
No full textIn order to fulfill the growing demands from the grid side, full-scale power converters are becoming popular in the wind turbine system. The low-voltage ride-through (LVRT) requirements may not only cause control problems but also result in overstressed components for the power converter. However, the thermal loading of the wind power converter under various grid faults is still not yet clarified, particularly at megawatt power level. In this paper, the impacts by three types of grid faults to a three-level neutral-point-clamped (3L-NPC) wind power converter in terms of operating and loading conditions are analytically solved and simulated. It has been found that the operating and loading conditions of the converter under LVRT strongly depend on the types/severity values of grid voltage dips and also the chosen control algorithms. The thermal distribution among the three phases of the converter may be quite uneven, and some devices are much more stressed than the normal operating condition
Advanced modeling and control of voltage source converters with LCL filters
No full textIn this chapter, various mathematical models of the voltage source converters with LCL filters are developed in the balanced/unbalanced three-phase power systems, including the commonly used moving averaged model and coordinate transformation technique, the generalized averaging model, and the harmonic state space model for unbalanced grid analysis. Afterward, the decoupling technique using complex variables is introduced to control the alternative grid current. Especially, focusing on the resonance phenomenon of LCL filter, different damping control methods are applied to suppress the peaky magnitude response and to soften the stepped phase transition. Next, a brief introduction of the positive-and negative-sequence current control under unbalanced grid voltages is presented. Finally, an impedance-based stability analysis method is explained. In each part, simulation results are shown to validate the theoretical analysis.</p
Chapter 8: Design and Control of Voltage Source Converters With LCL-Filters
No full textVoltage source converters use filters to connect to the grid in order to limit the harmonic content injected to the grid. Compared to a simple inductor (L-filter), LCL-filters result in a lower total inductance value. Losses are reduced and the dynamics are preserved, but stability problems can arise in the current-control loop if the LCL-filter resonance is not properly damped. Passive damping adds dissipative elements to the LCL-filter capacitors. The control software (nested controllers for current and DC voltage) does not need to be modified, but there are additional losses and encumbrances. In spite of its disadvantages, passive damping is widely used in the industry because of its simplicity. Active damping modifies the control algorithm to obtain current-control stability. The control procedure becomes more complex and sometimes additional sensors are necessary. Literature presents many options for the LCL-filter design, passive damping design, and active damping design, and this chapter will present well-known practical methods. In this chapter, the LCL-filter design uses a step-by-step procedure with simple formulas that avoid trial-and-error iterations. Different configurations for passive damping are shown with design and stability considerations along with simple formulas for estimating the passive damping losses. The procedures presented for active damping preserve the nested controller configuration, and they are feedback type and filter based. Feedback-type procedures result in a robust design against line inductance variations. The capacitor-current feedback method requires an additional sensor and the lead-lag network avoid additional sensors by using the capacitor voltage also for synchronization. The filter-based procedure presented in the chapter uses a notch filter at the voltage reference output to the modulator. The procedure is straightforward, but it may require an estimation of resonance frequency when large grid inductance variations are present. The techniques explained in this chapter constitute the basis of the past and the ongoing research on LCL-filter-based grid converters
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