7,995 research outputs found
Advanced control techniques for modern inertia based inverters
”In this research three artificial intelligent (AI)-based techniques are proposed to regulate the voltage and frequency of a grid-connected inverter. The increase in the penetration of renewable energy sources (RESs) into the power grid has led to the increase in the penetration of fast-responding inertia-less power converters. The increase in the penetration of these power electronics converters changes the nature of the conventional grid, in which the existing kinetic inertia in the rotating parts of the enormous generators plays a vital role. The concept of virtual inertia control scheme is proposed to make the behavior of grid connected inverters more similar to the synchronous generators, by mimicking the mechanical behavior of a synchronous generator. Conventional control techniques lack to perform optimally in nonlinear, uncertain, inaccurate power grids. Besides, the decoupled control assumption in conventional VSGs makes them nonoptimal in resistive grids.
The neural network predictive controller, the heuristic dynamic programming, and the dual heuristic dynamic programming techniques are presented in this research to overcome the draw backs of conventional VSGs. The nonlinear characteristics of neural networks, and the online training enable the proposed methods to perform as robust and optimal controllers. The simulation and the experimental laboratory prototype results are provided to demonstrate the effectiveness of the proposed techniques”--Abstract, page iv
Adaptive-critic-Based Optimal Neurocontrol for Synchronous Generators in a Power System using MLP/RBF Neural Networks
This paper presents a novel optimal neurocontroller that replaces the conventional controller (CONVC), which consists of the automatic voltage regulator and turbine governor, to control a synchronous generator in a power system using a multilayer perceptron neural network (MLPN) and a radial basis function neural network (RBFN). The heuristic dynamic programming (HDP) based on the adaptive critic design technique is used for the design of the neurocontroller. The performance of the MLPN-based HDP neurocontroller (MHDPC) is compared with the RBFN-based HDP neurocontroller (RHDPC) for small as well as large disturbances to a power system, and they are in turn compared with the CONVC. Simulation results are presented to show that the proposed neurocontrollers provide stable convergence with robustness, and the RHDPC outperforms the MHDPC and CONVC in terms of system damping and transient improvement
Multimodal imaging of human brain activity: rational, biophysical aspects and modes of integration
Until relatively recently the vast majority of imaging and electrophysiological studies of human brain activity have relied on single-modality measurements usually correlated with readily observable or experimentally modified behavioural or brain state patterns. Multi-modal imaging is the concept of bringing together observations or measurements from different instruments. We discuss the aims of multi-modal imaging and the ways in which it can be accomplished using representative applications. Given the importance of haemodynamic and electrophysiological signals in current multi-modal imaging applications, we also review some of the basic physiology relevant to understanding their relationship
Neural Network Predictive Controller for Grid-Connected Virtual Synchronous Generator
In this paper, a neural network predictive controller is proposed to regulate
the active and the reactive power delivered to the grid generated by a
three-phase virtual inertia-based inverter. The concept of the conventional
virtual synchronous generator (VSG) is discussed, and it is shown that when the
inverter is connected to non-inductive grids, the conventional PI-based VSGs
are unable to perform acceptable tracking. The concept of the neural network
predictive controller is also discussed to replace the traditional VSGs. This
replacement enables inverters to perform in both inductive and non-inductive
grids. The simulation results confirm that a well-trained neural network
predictive controller illustrates can adapt to any grid impedance angle,
compared to the traditional PI-based virtual inertia controllers.Comment: NAPS 2019 Conferenc
Modular Acquisition and Stimulation System for Timestamp-Driven Neuroscience Experiments
Dedicated systems are fundamental for neuroscience experimental protocols
that require timing determinism and synchronous stimuli generation. We
developed a data acquisition and stimuli generator system for neuroscience
research, optimized for recording timestamps from up to 6 spiking neurons and
entirely specified in a high-level Hardware Description Language (HDL). Despite
the logic complexity penalty of synthesizing from such a language, it was
possible to implement our design in a low-cost small reconfigurable device.
Under a modular framework, we explored two different memory arbitration schemes
for our system, evaluating both their logic element usage and resilience to
input activity bursts. One of them was designed with a decoupled and latency
insensitive approach, allowing for easier code reuse, while the other adopted a
centralized scheme, constructed specifically for our application. The usage of
a high-level HDL allowed straightforward and stepwise code modifications to
transform one architecture into the other. The achieved modularity is very
useful for rapidly prototyping novel electronic instrumentation systems
tailored to scientific research.Comment: Preprint submitted to ARC 2015. Extended: 16 pages, 10 figures. The
final publication is available at link.springer.co
Online Learning of Power Transmission Dynamics
We consider the problem of reconstructing the dynamic state matrix of
transmission power grids from time-stamped PMU measurements in the regime of
ambient fluctuations. Using a maximum likelihood based approach, we construct a
family of convex estimators that adapt to the structure of the problem
depending on the available prior information. The proposed method is fully
data-driven and does not assume any knowledge of system parameters. It can be
implemented in near real-time and requires a small amount of data. Our learning
algorithms can be used for model validation and calibration, and can also be
applied to related problems of system stability, detection of forced
oscillations, generation re-dispatch, as well as to the estimation of the
system state.Comment: 7 pages, 4 figure
Improvement of Power System Small-Signal Stability by Artificial Neural Network Based on Feedback Error Learning
Electrical power systems usually suffer from instabilities because of some disturbances occurring due to environmental conditions, system failures, and loading conditions. The most frequently encountered problem is the loss of synchronization between the rotor angle and the stator magnetic angle for synchronous generators. The contribution of this study is that a nonlinear adaptive control approach called feedback error learning (FEL) is utilized to improve the small-signal stabilities of an electric power system. The power system under study is composed of a synchronous machine connected to infinite bus. Many advantages of FEL control approach makes it capable to robustly adapting with all possible operating conditions rather than using optimization algorithms for tuning the conventional power system stabilizer (CPSS) that is still unsatisfactory especially at some critical operating points. The performances of two controllers, namely the proposed FEL scheme and the conventional controller CPSS, are tested by Matlab simulations. It is found that the FEL controller can be effectively used as an alternative stabilizer for improving small-signal stabilities of the powe
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