Performance Evaluation of Speed Platoon Splitting Algorithm

International audiencePlatooning of vehicles enhances traffic flow performance in transportation systems. Platoon is defined as a group of vehicles standing one behind another, moving in a line by keeping a very short vehicular gap. Many strategies for platoon formation have been proposed in the literature. These strategies aim to control platoon stability and platoon lifetime. Nevertheless, literature algorithms did not take into account the vehicular congestion problem and platoon velocity. Therefore, we propose a new algorithm, called speed platoon splitting (SPS) that targets alleviating congestion by using a ticket pool and classifies platoons according to the velocity using two different lanes. Performance analysis displays that SPS achieves platoon stability and reduces highway congestion

Stable Integration of Power Electronics-Based DG Links to the Utility Grid with Interfacing Impedance Uncertainties

Part 16: Energy: Power Conversion IIInternational audienceFor the integration of distributed generation (DG) units to the utility grid, voltage source converter (VSC) is the key technology. In order to realize high quality power injection, different control techniques have been adopted. However, the converter-based DG interface is subject to inevitable uncertainties, which adversely influence the performance of the controller. The interfacing impedance seen by the VSC may considerably vary in real distribution networks. It can be observed that the stability of the DG interface is highly sensitive to the impacts of interfacing impedance changes so that the controller cannot inject appropriate currents. To deal with the instability problem, this paper proposes an enhanced fractional order active sliding mode control scheme for integration of DG units to the utility grid, which is much less sensitive to interfacing impedance variations. A fractional sliding surface which demonstrates the desired dynamics of the system is developed and then the controller is designed in two phases: sliding phase and reaching phase to keep the control loop stable. The proposed controller takes a role to provide high quality power injection and ensures precise current tracking and fast response despite uncertainties. Theoretical analyses and simulation results are verified to study the performance and feasibility of the proposed control scheme

Strange attractors generated by a fractional order switching system and its topological horseshoe

"Chaos generation in a new fractional order unstable dissipative system with only two equilibrium points is reported. Based on the integer version of an unstable dissipative system (UDS) and using the same systems parameters, chaos behavior is observed with an order less than three, i.e., 2.85. The fractional order can be decreased as low as 2.4 varying the eigenvalues of the fractional UDS in accordance with a switching law that fulfills the asymptotic stability theorem for fractional systems. The largest Lyapunov exponent is computed from the numerical time series in order to prove the chaotic regime. Besides, the presence of chaos is also verified obtaining the topological horseshoe. That topological proof guarantees the chaos generation in the proposed fractional order switching system avoiding the possible numerical bias of Lyapunov exponents. Finally, an electronic circuit is designed to synthesize this fractional order chaotic system.