Stability analysis and robust damping of multiresonances in distributed-generation-based islanded microgrids

International audienc

Frequency-Adaptive Multi-Resonant LQG State-Feedback Current Controller for LCL-Filtered VSCs under Distorted Grid Voltages

This paper combines the well-known linear quadratic Gaussian (LQG) control and frequency-adaptive resonators and presents a frequency-adaptive multiresonant LQG state-feedback current controller for LCLfiltered voltage-source converters connected to a distorted grid. The paper also provides a design guideline and procedure based on robust control criteria which, in combination with the linear quadratic regulator (LQR) technique, offers flexibility in the control structure and automatizes the design of the controller. The frequencyadaptive resonators, based on second-order IIR resonators and on an on-line tuning algorithm, and the robustness criteria considered for the design process offer robustness in the face of grid voltage disturbances.The controller is evaluated and validated in a 9-kVA VSC setup configured as a rectifier.This work was supported in part by the Government of Spain through the Ministerio de Economía, Industria y Competitividad and Agencia Estatal de Investigación under Grants ENE2014-57760-C2-2-R, RTC-2015-3803-3, DPI2017-88505-C2-2-R and DPI2017-92258-EXP

Technical solutions for low-voltage microgrid concept

fi=vertaisarvioitu|en=peerReviewed

SIECI “SMART GRIDS” – WYZWANIA SYNCHRONIZACJI

This paper deals with crucial aspect of synchronization in modern power grids. It presents the concept of intelligent networks (“smart grids”), as the future of today’s grid infrastructure. The diversity of different grid codes in regards to the synchronization requirements for different Transmission System Operators (TSO) is discussed. This paper shows the applications of synchronizing algorithms, their role in power grid system.. The methods are classified according to application, the reference frame used and the possibility of using them in single and three phase systems. Proper selection of synchronization algorithms to meet the requirements of TSO’s calls for creation of appropriate evaluation methods. For this reason, at the end of the article quality criteria for the evaluation of synchronizing algorithms were proposed and explained in detail. Finally, the last section states what are the most commonly used methods for grid synchronization.Niniejszy artykuł zajmuje się kluczowym aspektem, jakim jest synchronizacja w nowoczesnych sieciach elektroenergetycznych. Przedstawia on koncepcję sieci inteligentnych („smart grids”),uważaną jako przyszłość dzisiejszej infrastruktury sieciowej. Omówiono w nim różnice w zakresie przepisów sieci energetycznych różnych operatorów w odniesieniu do wymagań synchronizacji z siecią. Opisane metody sklasyfikowano według ich typowych aplikacji, zastosowanego układu odniesienia i możliwości zastosowania w systemie jedno- lub trójfazowym. Odpowiedni dobór algorytmów synchronizacji by spełnić wymagania TSO postuluje powstanie właściwych  metod oceny tych algorytmów. Z tego powodu ostatni punkt artykułu opisuje i wyjaśnia szczegółowo dobrane kryteria oceny jakości algorytmów do synchronizacji. W ostatniej sekcji artykułu pokazano jakie są najczęściej stosowane metody do synchronizacji z siecią

A review of compensation topologies and control techniques of bidirectional wireless power transfer systems for electric vehicle applications

Owing to the constantly rising energy demand, Internal Combustion Engine (ICE)-equipped vehicles are being replaced by Electric Vehicles (EVs). The other advantage of using EVs is that the batteries can be utilised as an energy storage device to increase the penetration of renewable energy sources. Integrating EVs with the grid is one of the recent advancements in EVs using Vehicle-to-Grid (V2G) technology. A bidirectional technique enables power transfer between the grid and the EV batteries. Moreover, the Bidirectional Wireless Power Transfer (BWPT) method can support consumers in automating the power transfer process without human intervention. However, an effective BWPT requires a proper vehicle and grid coordination with reasonable control and compensation networks. Various compensation techniques have been proposed in the literature, both on the transmitter and receiver sides. Selecting suitable compensation techniques is a critical task affecting the various design parameters. In this study, the basic compensation topologies of the Series-Series (SS), Series-Parallel (SP), Parallel-Parallel (PP), Parallel-Series (SP), and hybrid compensation topology design requirements are investigated. In addition, the typical control techniques for bidirectional converters, such as Proportional-Integral-Derivative (PID), sliding mode, fuzzy logic control, model predictive, and digital control, are discussed. In addition, different switching modulation schemes, including Pulse-Width Modulation (PWM) control, PWM + Phase Shift control, Single-Phase Shift, Dual-Phase Shift, and Triple-Phase Shift methods, are discussed. The characteristics and control strategies of each are presented, concerning the typical applications. Based on the review analysis, the low-power (Level 1/Level 2) charging applications demand a simple SS compensation topology with a PID controller and a Single-Phase Shift switching method. However, for the medium- or high-power applications (Level 3/Level 4), the dual-side LCC compensation with an advanced controller and a Dual-Side Phase-Shift switching pattern is recommended.Web of Science1520art. no. 781