This paper addresses the traction control problem for the electrical vehicles (EVs) driven by permanent magnet synchronous motor (PMSM). A robust nonlinear control law at the torque level is proposed firstly to cope with the unknown tire reaction force. A parameter estimation mechanism will be introduced to the adaptive control scheme of the system with unknown friction forces. Then, a new torque control strategy for PMSM with vector transformation is introduced to achieve the desired torque for the robust traction. It is shown that by using a kind of backstepping design approach, the goal of traction control can be achieved at electrical control level of the PMSM.
The torque-speed characteristics of an interior magnet brushless motor are compared with particular reference to the flux-weakening performance for EV/HEV applications, when it is operated in brushless AC (BLAC) mode, with 3-phase, sinusoidal current waveforms, and in brushless DC (BLDC) mode with both 2-phase, 120° conduction and 3-phase, 180° conduction rectangular current waveforms. It is shown that while 2-phase, 120° BLDC operation results in the highest torque capability for the same peak current and BLAC operation results in the highest specific torque per rms current when operating below the base-speed, 3-phase, 180° BLDC operation generally results in the best performance in the flux-weakening region.
Hybrid electric vehicles (HEVs) offer many advantages, such as high fuel economy, low emissions, and silent operation. In HEVs, there are two or more different voltage buses for different purposes of the vehicle operation. There are needs of galvanically isolated bidirectional DC-DC converter to link different DC voltage bus and transfer energy back and forth. For example, one of the DC-DC converters convert the high voltage (200-300V) in the main battery to low voltage (-12V) for use in electrical equipment, while the other converts 300V battery voltage and supply the drive motor with 500V. High efficiency, compact size, lightweight, and reliability are all essential requirements for DC-DC converters for electric and hybrid vehicles. This paper introduces a bidirectional, isolated DC-DC converter for medium power applications. A dual full-bridge topology is developed to achieve the power rating. A 1kW prototype of the converter has been built and tested. The experimental results of the converter's steady state operation confirm the simulation analysis. This converter is a first step to understanding the design and build of a medium power DC-DC converter.
In future planetary exploration missions, rovers are required to traverse over very rough terrain. The Moon's surface is covered with soil which is named regolith. Regolith is easy to slide. A stack occurs to the rovers which are running on the regolith. The cause of the stack is not yet clear. At first, this paper investigates kinematics behavior of lunar rovers with a tire-soil traction mechanism where the condition of the moon is a vacuum. In vacuum condition, experiment of the running is carried out, and, air and vacuum conditions are compared. Finally, this paper considers whether experiment of vacuum is effective on the earth.
This paper presents a new estimation approach of residual available capacity for lead acid batteries in electric vehicles (EVs). The essence of this approach is to model lead acid batteries in EVs by using a neural network (NN) with the specially defined output and the proposed inputs. The inputs are the battery surface temperature and the discharged and regenerative capacity distribution to describe the discharge current profiles of lead acid batteries during EV operations. The output is the state of available capacity (SOAC) representing battery residual available capacity (BRAC). Then, SOACs of lead-acid batteries in EVs are experimentally investigated under different EV discharge current profiles in the presence of various battery surface temperatures. The corresponding data are recorded to train and verify the NN. The results indicate that the proposed NN can provide accurate and effective BRAC estimation for lead-acid batteries in EVs.
The car of today is a concept of an internal combustion engine vehicle (ICEV) that is based upon merely the packaging of the engine that is expanded to the body structure of the vehicle. Applying fine electric vehicle (EV) technology a renewed car transportation is created to solve the problems of today's traffic jams, car accidents and transportation smog. A concept of a 'Modular Multi-functional Electric Vehicle (MMEV) is originated, which is a composed system design of 1, 3, 6 or 8 battery-modules of 600mm in width and 900mm in length. This concept innovates transportation over a time span of 5, 10 or 20 years applying four types of MMEVs: the MMEV-Chair, -Tatami, -Road and -Room. It makes it possible to climb staircases, to double the capacity of today's traffic or to offer space of 2,400mm in width for the weaker road user while keeping today's road capacity the same and to integrate indoor and outdoor use of a vehicle while managing time and making communication with people more easily. In this paper the development process is explained, concept sketches are proposed, models are made and verified and a real first running chassis of an MMEV-Tatami is realized to evaluate its size, floor base and hands-free driving mode.
Chinese E-bike batteries are 36 volt (10 or 12Ah) connecting three 10 or 12Ah batteries in series. The battery life is 6-12 months when used its 70 to 80% capacity each cycle of the each use is only 30% of the capacity, the cycle life will be over 1,000 cycles. In this paper, outline of the bicycle and the batteries are described. Also, the authors attempted to regenerate deteriorated or abandoned batteries. The regeneration treatment produced useful batteries with ITE's Super-K Activator. The regeneration rate was 50 to 70% of the total batteries. The capacity maintenance test for the new 10Ah E-bike batteries with or without ITE Activator. We confirmed that ITE Activator is useful for extending the battery life and reduce the waste battery, contributing greatly to our environment.
This paper describes engineering education achievements performed by 4th year synthesis class. Since its inauguration in April 1997 the Kochi University of Technology has overseen nine years of engineering education and the objectives of the synthesis class are based on this experience. Knowledge of design and manufacturing is considered to be as important as the basic sciences of mathematics and physics for mechanical engineering, and laboratory experience provides an active learning opportunity alongside classroom learning. As a capstone learning course, student teams in our laboratory have designed and manufactured hand-made electric vehicles. This project provides useful information to consider the future design and the production process of EV. Their experiences are reported here.
The discharge performance of commercial available new lead-acid batteries for cars were studied by addition of ITE's activators at about 90A of discharge current to a depth of 9V. The addition of activators showed that the battery deterioration with charge and discharge cycles was depressed. It is suggested that the addition of activators are recommended for the new batteries in commercial or production process. When the charge is performed without regulation of cut-off voltage, specific gravity of electrolyte and cell voltage are increased with charge-discharge cycles.