scholarly journals Generic characterization of electrical test benches for AC- and HVDC-connected wind power plants

2020 ◽  
Vol 5 (2) ◽  
pp. 561-575
Author(s):  
Behnam Nouri ◽  
Ömer Göksu ◽  
Vahan Gevorgian ◽  
Poul Ejnar Sørensen
Keyword(s):  
Real Time ◽  
Wind Power ◽  
Wind Turbines ◽  
Closed Loop ◽  
Short Circuit ◽  
Open Loop ◽  
Device Under Test ◽  
Generic Structure ◽  
Electrical Test ◽  
Grid Connection

Abstract. The electrical test and assessment of wind turbines go hand in hand with standards and network connection requirements. In this paper, the generic structure of advanced electrical test benches, including grid emulator or controllable grid interface, wind torque emulator, and device under test, is proposed to harmonize state-of-the-art test sites. On the other hand, modern wind turbines are under development towards new features, concerning grid-forming, black-start, and frequency support capabilities as well as harmonic stability and control interaction considerations, to secure the robustness and stability of renewable-energy-based power systems. Therefore, it is necessary to develop new and revised test standards and methodologies to address the new features of wind turbines. This paper proposes a generic test structure within two main groups, including open-loop and closed-loop tests. The open-loop tests include the IEC 61400-21-1 standard tests as well as the additional proposed test options for the new capabilities of wind turbines, which replicate grid connection compliance tests using open-loop references for the grid emulator. In addition, the closed-loop tests evaluate the device under test as part of a virtual wind power plant and perform real-time simulations considering the grid dynamics. The closed-loop tests concern grid connection topologies consisting of AC and HVDC, as well as different electrical characteristics, including impedance, short-circuit ratio, inertia, and background harmonics. The proposed tests can be implemented using available advanced test benches by adjusting their control systems. The characteristics of a real power system can be emulated by a grid emulator coupled with real-time digital simulator systems through a high-bandwidth power-hardware-in-the-loop interface.

scholarly journals Design Considerations for Long Term Non-invasive Brain Computer Interface Training With Tetraplegic CYBATHLON Pilot

2021 ◽  
Vol 15 ◽  
Author(s):  
Neethu Robinson ◽  
Tushar Chouhan ◽  
Ernest Mihelj ◽  
Paulina Kratka ◽  
Frédéric Debraine ◽  
...  
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Brain Computer Interface ◽  
Brain Activation ◽  
Classification Performance ◽  
Open Loop ◽  
Computer Interface ◽  
Single Subject ◽  
User Engagement

Several studies in the recent past have demonstrated how Brain Computer Interface (BCI) technology can uncover the neural mechanisms underlying various tasks and translate them into control commands. While a multitude of studies have demonstrated the theoretic potential of BCI, a point of concern is that the studies are still confined to lab settings and mostly limited to healthy, able-bodied subjects. The CYBATHLON 2020 BCI race represents an opportunity to further develop BCI design strategies for use in real-time applications with a tetraplegic end user. In this study, as part of the preparation to participate in CYBATHLON 2020 BCI race, we investigate the design aspects of BCI in relation to the choice of its components, in particular, the type of calibration paradigm and its relevance for long-term use. The end goal was to develop a user-friendly and engaging interface suited for long-term use, especially for a spinal-cord injured (SCI) patient. We compared the efficacy of conventional open-loop calibration paradigms with real-time closed-loop paradigms, using pre-trained BCI decoders. Various indicators of performance were analyzed for this study, including the resulting classification performance, game completion time, brain activation maps, and also subjective feedback from the pilot. Our results show that the closed-loop calibration paradigms with real-time feedback is more engaging for the pilot. They also show an indication of achieving better online median classification performance as compared to conventional calibration paradigms (p = 0.0008). We also observe that stronger and more localized brain activation patterns are elicited in the closed-loop paradigm in which the experiment interface closely resembled the end application. Thus, based on this longitudinal evaluation of single-subject data, we demonstrate that BCI-based calibration paradigms with active user-engagement, such as with real-time feedback, could help in achieving better user acceptability and performance.

scholarly journals Modelling Types 1 and 2 Wind Turbines Based on IEC 61400-27-1: Transient Response under Voltage Dips

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4078 ◽  
Author(s):  
Tania García-Sánchez ◽  
Irene Muñoz-Benavente ◽  
Emilio Gómez-Lázaro ◽  
Ana Fernández-Guillamón
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Distribution System ◽  
Power Plants ◽  
Short Circuit ◽  
Energy Resource ◽  
Weather Conditions ◽  
International Electrotechnical Commission ◽  
Voltage Dips

Wind power plants depend greatly on weather conditions, thus being considered intermittent, uncertain and non-dispatchable. Due to the massive integration of this energy resource in the recent decades, it is important that transmission and distribution system operators are able to model their electrical behaviour in terms of steady-state power flow, transient dynamic stability, and short-circuit currents. Consequently, in 2015, the International Electrotechnical Commission published Standard IEC 61400-27-1, which includes generic models for wind power generation in order to estimate the electrical characteristics of wind turbines at the connection point. This paper presents, describes and details the models for wind turbine topologies Types 1 and 2 following IEC 61400-27-1 for electrical simulation purposes, including the values for the parameters for the different subsystems. A hardware-in-the-loop combined with a real-time simulator is also used to analyse the response of such wind turbine topologies under voltage dips. The evolution of active and reactive powers is discussed, together with the wind turbine rotor and generator rotational speeds.

scholarly journals Equivalent Modeling of DFIG-Based Wind Power Plant Considering Crowbar Protection

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Qianlong Zhu ◽  
Ming Ding ◽  
Pingping Han
Keyword(s):  
Wind Power ◽  
Power Plants ◽  
Short Circuit ◽  
Grid Connection ◽  
Wind Power Plants ◽  
Voltage Dip ◽  
Terminal Voltage ◽  
Current Characteristics ◽  
Doubly Fed ◽  
Crowbar Protection

Crowbar conduction has an impact on the transient characteristics of a doubly fed induction generator (DFIG) in the short-circuit fault condition. But crowbar protection is seldom considered in the aggregation method for equivalent modeling of DFIG-based wind power plants (WPPs). In this paper, the relationship between the growth of postfault rotor current and the amplitude of the terminal voltage dip is studied by analyzing the rotor current characteristics of a DFIG during the fault process. Then, a terminal voltage dip criterion which can identify crowbar conduction is proposed. Considering the different grid connection structures for single DFIG and WPP, the criterion is revised and the crowbar conduction is judged depending on the revised criterion. Furthermore, an aggregation model of the WPP is established based on the division principle of crowbar conduction. Finally, the proposed equivalent WPP is simulated on a DIgSILENT PowerFactory platform and the results are compared with those of the traditional equivalent WPPs and the detailed WPP. The simulation results show the effectiveness of the method for equivalent modeling of DFIG-based WPP when crowbar protection is also taken into account.

scholarly journals Real-time synthesis of imagined speech processes from minimally invasive recordings of neural activity

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Miguel Angrick ◽  
Maarten C. Ottenhoff ◽  
Lorenz Diener ◽  
Darius Ivucic ◽  
Gabriel Ivucic ◽  
...  
Keyword(s):  
Real Time ◽  
Neural Activity ◽  
Communication Channel ◽  
Closed Loop ◽  
Open Loop ◽  
Depth Electrodes ◽  
Whispered Speech ◽  
Frontal Activity ◽  
Synthesis Approach

AbstractSpeech neuroprosthetics aim to provide a natural communication channel to individuals who are unable to speak due to physical or neurological impairments. Real-time synthesis of acoustic speech directly from measured neural activity could enable natural conversations and notably improve quality of life, particularly for individuals who have severely limited means of communication. Recent advances in decoding approaches have led to high quality reconstructions of acoustic speech from invasively measured neural activity. However, most prior research utilizes data collected during open-loop experiments of articulated speech, which might not directly translate to imagined speech processes. Here, we present an approach that synthesizes audible speech in real-time for both imagined and whispered speech conditions. Using a participant implanted with stereotactic depth electrodes, we were able to reliably generate audible speech in real-time. The decoding models rely predominately on frontal activity suggesting that speech processes have similar representations when vocalized, whispered, or imagined. While reconstructed audio is not yet intelligible, our real-time synthesis approach represents an essential step towards investigating how patients will learn to operate a closed-loop speech neuroprosthesis based on imagined speech.

scholarly journals Impact of wind power grid connection and interline short circuit faults on power grid

2019 ◽  
Vol 612 ◽  
pp. 042005
Author(s):  
Jiasong Luo ◽  
Tong Xu ◽  
Xinlei Wang ◽  
Chao Zhang ◽  
Nan Li
Keyword(s):  
Wind Power ◽  
Short Circuit ◽  
Power Grid ◽  
Grid Connection

scholarly journals Design of a Research Laboratory Drive System for a Synchronous Reluctance Motor for Vector Control and Performance Analysis

Inventions ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 64
Author(s):  
Hamidreza Heidari ◽  
Anton Rassõlkin ◽  
Ants Kallaste ◽  
Toomas Vaimann ◽  
Ekaterina Andriushchenko ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Vector Control ◽  
Real Time ◽  
Research Laboratory ◽  
Closed Loop ◽  
Open Loop ◽  
Drive System ◽  
Control Algorithms ◽  
Synchronous Reluctance Motor ◽  
Reluctance Motor

Motor-drive systems have the most significant share in industrial energy consumption, which requires a deep study in every aspect of the field. This paper presents a synchronous reluctance motor (SynRM) drive system based on Plecs RT box 1. The system’s design provides the opportunity for the open-loop and closed-loop control of the motor and a characteristic performance analysis of the motor. This paper focuses on the hardware implementation of a research laboratory setup and the precise vector control of the SynRM in real-time. The application of the digital controller and inverter to drive SynRM is examined. The voltage, current, and speed transducers were employed for monitoring the protective measures and to control the motor in the closed-loop. The design of the signal conditioning and the intermediary cards for isolation and data acquisition are described in detail. An algorithm is proposed to measure the whole system parameters, including motor, inverter, and cables. Thanks to the RT box 1, the principle of real-time simulation of control algorithms is investigated, and the rapid control prototyping of field-oriented control (FOC) of SynRM was implemented. The simulation of the system was carried out in the Plecs platform, and the results are presented. The experimental results of the implemented control algorithms validate the setup’s performance and the control algorithm. Finally, as a study of the motor’s performance, the efficiency map of the motor is drawn in different speed and torque ranges.

scholarly journals Proposal for Generic Characterization of Electrical Test Benches for AC- and HVDC-Connected Wind Power Plants

2019 ◽  
Author(s):  
Behnam Nouri ◽  
Ömer Göksu ◽  
Vahan Gevorgian ◽  
Poul Ejnar Sørensen
Keyword(s):  
Power System ◽  
Wind Power ◽  
Power Plants ◽  
Short Circuit ◽  
General Structure ◽  
Industrial Test ◽  
Electrical Characteristics ◽  
Electrical Test ◽  
Wind Power Plants ◽  
Real Time Digital Simulator

Abstract. The electrical test and assessment of wind turbines (WT) are going hand in hand with standards and network connection requirements. In this paper, the latest developments in the testing of the electrical characteristics of WTs, including IEC standards, compliance test methods, and industrial test benches, are studied. In this paper, the general structure of advanced electrical test benches, including grid emulator or controllable grid interface (CGI), wind torque emulator and device under test (DUT), has been proposed to harmonize the available industrial test sites. The AC and HVDC transmission systems impose different electrical characteristics on wind power plants (WPP). HVDC connection leads to a converter-based grid, yet AC connection has different grid characteristics in terms of grid impedance, short circuit ratio (SCR), inertia, and background harmonics. Therefore, this paper recommends performing compliance tests in two divisions as AC- and HVDC-connected WTs using a converter-based CGI and emulate the corresponding AC grid for DUT. Also, this paper recommends the additional tests for the current version of IEC 61400-21-1. The additional tests consist of test options for new features of modernWTs, such as Grid-forming, system restoration, and black start capabilities, as well as emulation of different grid characteristics, such as detailed power system, inertia, SCR, and different grid connection emulations for DUT. This way, the possibility of research, development, and demonstration studies on WTs and WPPs would increase. The proposed additional tests can be implemented using the available advanced test benches by adjusting their control systems. Since most of the industrial test benches are based on converters, the characteristics of a real power system can be emulated by a CGI coupled with real-time digital simulator (RTDS) systems through high-bandwidth power-hardware-in-the-loop (PHIL) interface.

scholarly journals Clinical applications of neurochemical and electrophysiological measurements for closed-loop neurostimulation

2020 ◽  
Vol 49 (1) ◽  
pp. E6 ◽  
Author(s):  
J. Blair Price ◽  
Aaron E. Rusheen ◽  
Abhijeet S. Barath ◽  
Juan M. Rojas Cabrera ◽  
Hojin Shin ◽  
...  
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Neurological Diseases ◽  
Pulse Frequency ◽  
Open Loop ◽  
Compulsive Disorder ◽  
Specific Disease ◽  
Disease States ◽  
Stimulation Parameters ◽  
The Individual

The development of closed-loop deep brain stimulation (DBS) systems represents a significant opportunity for innovation in the clinical application of neurostimulation therapies. Despite the highly dynamic nature of neurological diseases, open-loop DBS applications are incapable of modifying parameters in real time to react to fluctuations in disease states. Thus, current practice for the designation of stimulation parameters, such as duration, amplitude, and pulse frequency, is an algorithmic process. Ideal stimulation parameters are highly individualized and must reflect both the specific disease presentation and the unique pathophysiology presented by the individual. Stimulation parameters currently require a lengthy trial-and-error process to achieve the maximal therapeutic effect and can only be modified during clinical visits. The major impediment to the development of automated, adaptive closed-loop systems involves the selection of highly specific disease-related biomarkers to provide feedback for the stimulation platform. This review explores the disease relevance of neurochemical and electrophysiological biomarkers for the development of closed-loop neurostimulation technologies. Electrophysiological biomarkers, such as local field potentials, have been used to monitor disease states. Real-time measurement of neurochemical substances may be similarly useful for disease characterization. Thus, the introduction of measurable neurochemical analytes has significantly expanded biomarker options for feedback-sensitive neuromodulation systems. The potential use of biomarker monitoring to advance neurostimulation approaches for treatment of Parkinson’s disease, essential tremor, epilepsy, Tourette syndrome, obsessive-compulsive disorder, chronic pain, and depression is examined. Further, challenges and advances in the development of closed-loop neurostimulation technology are reviewed, as well as opportunities for next-generation closed-loop platforms.

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