Exclusive Operation Strategy for the Supervisory Control of Series Hybrid Electric Vehicles

Supervisory control systems (SCSs) are used to manage the powertrain of hybrid electric vehicles (HEV). This paper presents a novel SCS called Exclusive operation strategy (XOS) that applies simple rules based on the idea that batteries are efficient at lower loads while engines and generators are efficient at higher loads. The XOS is developed based on insights gained from three conventional SCSs for series HEVs: Thermostat control strategy (TCS), Power follower control strategy (PFCS) and Global equivalent consumption minimization strategy (GECMS). Also, recent technological developments have been considered to make the XOS more suited to modern HEVs than conventional SCSs. The resulting control decisions are shown to emulate the operation of approximate global optimal solutions and thus achieve significant improvement in fuel economy as compared to TCS and PFCS. In addition, the generally linear relationship between required power and engine power for the XOS provides auditory cues to the driver that are comparable to conventional vehicles, thus reducing barriers to adopting HEVs. The simplicity and effectiveness of the XOS makes it a practical SCS

Dynamic modeling platform for series hybrid electric vehicles

This paper introduces a simulation model that can be used to develop and test designs and control systems for hybrid electric vehicles (HEVs). The work involves a novel simulating platform, developed in Simulink, where each component of a series HEV is developed using a first-principles approach in a modular fashion, validated by available experimental data and then integrated to form a coupled nonlinear dynamic model. The vehicle model is capable to act as a platform for the design of supervisory control systems (SCSs) that optimize the energy flow in the powertrain. Simulations with two distinct SCSs and two driving cycles are used to analyze the vehicle performance under varying driving and operating conditions. The results demonstrate the applicability of the model for realistic prediction of both vehicle behavior and component energy losses, design optimization and control system design

Mode properties of annular gain lasers

The properties of a new class of laser resonators are investigated theoretically and experimentally. In these lasers the radiation propagates longitudinally in an annular amplifying medium, and useful low loss modes can be obtained even when the axial region is obscured. Alignment characteristics and far field patterns are discussed, and experiments have been conducted using coaxial double-discharge CO₂ devices

Air Breakdown in a Radial-Mode Focusing Element

A new radial focusing device is described that condenses an incident laser beam to an extremely intense and uniformly illuminated focal spot. The focal region is useful for many applications. When used with a 10.6-µm CO₂ TEA laser source, a disk-shaped air-breakdown spark results, and the properties of this spark have been investigated

Discrimination and visualization of ELM types based on a probabilistic description of inter-ELM waiting times

Discrimination and visualization of different observed classes of edge-localized plasma instabilities (ELMs), using advanced data analysis techniques has been considered. An automated ELM type classifier which effectively incorporates measurement uncertainties is developed herein and applied to the discrimination of type I and type III ELMs in a set of carbon-wall JET plasmas. The approach involves constructing probability density functions (PDFs) for inter-ELM waiting times and global plasma parameters and then utilizing an effective similarity measure for comparing distributions: the Rao geodesic distance (GD). It is demonstrated that complete probability distributions of plasma parameters contain significantly more information than the measurement values alone, enabling effective discrimination of ELM type

Weyl collineations that are not curvature collineations

Though the Weyl tensor is a linear combination of the curvature tensor, Ricci tensor and Ricci scalar, it does not have all and only the Lie symmetries of these tensors since it is possible, in principle, that "asymmetries cancel". Here we investigate if, when and how the symmetries can be different. It is found that we can obtain a metric with a finite dimensional Lie algebra of Weyl symmetries that properly contains the Lie algebra of curvature symmetries. There is no example found for the converse requirement. It is speculated that there may be a fundamental reason for this lack of "duality".Comment: 9 page