有源电压箝位串联HV IGBT的适用性和优化(二)

介绍了5.2 kV高压绝缘栅双极型晶体管(HV IGBTs)的成功串联应用.穿通型HV IGBT串联应用时要完全控制感应过电压,最大的障碍是拖尾电流的关断问题.可以证明,采用先进的电压箝位技术能够限制因关断拖尾电流而引起的第二个电压尖峰.阳极采用载流子寿命局部分布的IGBT很适合这种应用;拖尾电流间隔时间越短,关断损耗越小.文中集中讨论了穿通型HV IGBT器件串联时的最佳通态等离子体分布,HV IGBT的最新发展趋势似乎与讨论结论相一致.未来先进的HV IGBT技术可完全减轻第一代HV IGBT串联时的困难.     

An economic assessment of the impacts of the MOSE barriers on Venice port activities

To protect Venice from flooding, a number of protective measures have been adopted, including a system of mobile barriers known as MOSE. These separate the lagoon from the surges in the Adriatic Sea but interfere with shipping and on port activities. We estimate direct costs on ship traffic resulting from the use of MOSE, i.e., the additional costs of longer waiting time when passing through the Venice Lagoon. Our estimate uses inputs from a hydrodynamic model applied to the ship traffic between 2000 and 2002 and indicate that these costs range from €347,943 to €1.3 million a year, depending on the hypotheses adopted.     

Range Extender Module Transmission Topology Study

Range extender modules are one option to compensate for short drive ranges of electric vehicles. The close interaction of combustion engine and generator poses new challenges in development. A key requirement for range extender systems is to be light and virtually imperceptible in operation. High-speed electrical machines aim at increasing power density. However, their introduction in a range extender requires a gearbox. The combustion engine torque fluctuations can lead to rattle in the gearbox. The rattle can be overcome by a dual mass flywheel. An interdisciplinary model is developed and used to analyse three different range extender systems: one with a low speed generator without gearbox, one with a high-speed generator, and one with a high-speed generator and a dual mass flywheel. The efficiency was found to be higher for the system with a low speed generator, whereas the power density and the costs are beneficial for the high-speed concept. A dual mass flywheel eliminates the changes of torque direction in the gearbox. It reduces the speed fluctuations of the gearbox and generator by over 90 % compared to the low speed setup. But it increases rolling moment and subsequently chassis excitation compared to a setup with only a gearbox.     

The impact of fuel availability on demand for alternative-fuel vehicles

We study the impact of fuel availability on demand for alternative-fuel vehicles, using data from a survey of potential car buyers in Germany. The survey was conducted as a computer-assisted personal interview and included a choice experiment involving cars with various fuel types. Applying a standard logit model, we show that alternative fuel availability influences choices positively, but its marginal utility diminishes with supply. Furthermore, we derive consumers’ marginal willingness-to-pay for an expanded service station network. The results suggest that a failure to expand the availability of alternative fuel stations represents a significant barrier to the widespread adoption of alternative-fuel vehicles.     

On the Destabilizing Effect of Liquids in Various Vehicles* (part 1)

The unrestrained free surface of a liquid has an alarming propensity to undergo large excursions for even very small motions of the container. This fact may endanger the stability, as well as the riding and maneuvering quality of the vehicle considerably. It is particularly true for fuel- or cargo tanks of automotive vehicles, railroad tank cars, for fuel tanks of large ships and tankers, for which violent sea conditions at times result in fairly large amplitudes of pitching, heaving and rolling, as well as for airplanes and spacevehicles flying through atmospheric disturbances. The response of liquids contained in cargo- or fuel tanks is therefore of quite some concern, especially in those cases where the sloshing liquid masses occupy a large amount of the total mass of the vehicle.

For this reason the theory of liquid motion with a free surface is presented for containers of various geometries. Forces and moments of the liquid exerted upon the vehicle are presented and a simple mechanical model for the representation of the liquid motion is derived. Methods for the reduction of the destabilizing effect of the liquid motion, such as baffles, cross walls and surface coverings are presented and shall exhibit their effectiveness. In addition the interaction of the liquid motion with the elastic structure of the container, as well as the interaction with a controlling system of the vehicle shall be demonstrated. Stability boundaries, design criteria and dynamic responses to disturbances shall be presented for a particular case.     

User-Appropriate Tyre-Modelling for Vehicle Dynamics in Standard and Limit Situations

Summary When modelling vehicles for the vehicle dynamic simulation, special attention must be paid to the modelling of tyre-forces and -torques, according to their dominant influence on the results. This task is not only about sufficiently exact representation of the effective forces but also about user-friendly and practical relevant applicability, especially when the experimental tyre-input-data is incomplete or missing. This text firstly describes the basics of the vehicle dynamic tyre model, conceived to be a physically based, semi-empirical model for application in connection with multi-body-systems (MBS). On the basis of tyres for a passenger car and a heavy truck the simulated steady state tyre characteristics are shown together and compared with the underlying experimental values. In the following text the possibility to link the tyre model TMeasy to any MBS-program is described, as far as it supports the 'Standard Tyre Interface' (STI). As an example, the simulated and experimental data of a heavy truck doing a standardized driving manoeuvre are compared.     

德国城市轨道交通的各种制式系统

鉴于中国的城市轨道交通建设已进入了加速发展的大好时期,但由于地铁项目投资巨大,工期长,而且运营、维护成本也很高,地铁不可能满足中国所有城市轨道交通发展的需求,故而必然会转向采用投资较少的其他轨道交通制式.为此,介绍了欧洲大都市轨道交通系统的主要特征,重点阐述了德国城市轨道交通的各种制式系统,包括区域线、市域线、地铁、轻轨等现代城市轨道交通的各方面情况,以供中国同行参考.     

有源电压箝位串联HV IGBT的适用性和优化(一)

介绍了5.2 kV高压绝缘栅双极型晶体管(HV IGBTs)的成功串联应用.穿通型HV IGBT串联应用时要完全控制感应过电压,最大的障碍是拖尾电流的关断问题.可以证明,采用先进的电压箝位技术能够限制因关断拖尾电流而引起的第二个电压尖峰.阳极采用载流子寿命局部分布的IGBT很适合这种应用;拖尾电流间隔时间越短,关断损耗越小.文中集中讨论了穿通型HV IGBT器件串联时的最佳通态等离子体分布,HV IGBT的最新发展趋势似乎与讨论结论相一致.未来先进的HV IGBT技术可完全减轻第一代HV IGBT串联时的困难.     

Fuzzy Logic Traction Controllers and their Effect on Longitudinal Vehicle Platoon Systems

This paper presents two fuzzy logic traction controllers and investigates their effect on longitudinal platoon systems. A fuzzy logic approach is appealing for traction control because of the nonlinearity and time-varying uncertainty involved in traction control systems

The fuzzy logic traction controllers we present regulate brake torque to control wheel slip, which is the normalized difference between wheel and vehicle speed. One fuzzy controller estimates the peak slip corresponding to the maximum tire-road adhesion coefficient and regulates wheel slip at the peak slip. The controller is attractive because of its ability to maximize acceleration and deceleration regardless of road condition. However, we find through simulations the controller's performance degrades in the presence of time-varying uncertainties. The other fuzzy logic controller regulates wheel slip at any desired value. Through simulations we find the controller robust against changing road conditions and uncertainties. The target slip is predetermined and not necessarily the peak slip for all road conditions. If the target slip is set low, stable acceleration and deceleration is guaranteed, regardless of road condition

We also study the effect of traction control on longitudinal vehicle platoon systems using simulations. The simulations include acceleration and deceleration maneuvers on an icy road. The results indicate traction control may substantially improve longitudinal platoon performance, especially when icy road conditions exist.