Researches

Researches in 2017

  1. Wireless Power Transmission
  2. Magnetic Levitation - Linear Drive
  3. Energy and Electric Drive Control of Railway Vehicle
  4. Wave Generator

Wireless Power Transmission

Optimization of Electric Vehicle Operation and Indrastracture of Wireless Power transfer System

VAN DUC DOAN

Electric vehicle (EV) is becoming popular in near future to replace internal combustion engine vehicle (ICV) because EV is a solution for environment issues and fossil fuel exhausts caused by ICV. However, the main drawbacks of conventional EVs include short driving range per charge, heavy on-board battery, inconvenience for users, and sparking effects due to charging of EV via plug-in connector, etc. With developments of wireless power transfer (WPT) technology, all of these drawbacks can be overcome. EV will be conveniently charged without any mechanical contact, so there are no sparking effects. By installing WPT system on the road, EV can be powered from the road. Therefore, the concept of driving range per charge seems non-existent, and only a small on-board battery is required as a supporter.

In order to put WPT technology for EV into practical use, infrastructure of WPT system plays an important role to reduce its system cost and guarantee the smooth operation of EV as desired. It can be seen that if WPT system is equipped the road entirely, the construction cost is unacceptably expensive and not really necessary in particular cases. Therefore, for minimizing the total length of WPT system installed on the road, strategy to allocate the WPT system is non-trivial. In this work, the author presents a new approach for allocating WPT system from viewpoint of an optimal control problem, where the global optimality of solution is guaranteed.

Furthermore, in the conventional approach for allocation of WPT system, information of EV operation such as EV speed profile and power demand is required. In this work, the author also proposes a new methodology based on mathematical optimization method for simultaneously designing EV speed profile and allocation of WPT system in a lane segment, with the aim to reduce the cost of WPT system by minimizing its length. By parameterizing both EV operation and allocation of WPT system as unknown parameters, a nonlinear optimization problem with involved constraints of EV operation and battery sustainability is established for optimizing these unknown parameters to minimize the length of WPT system. Therefore, optimal speed profile of EV and optimal allocation of WPT system can be simultaneously determined. The proposed approach is applied in a scenario of autonomous driving EVs, where they will accurately follow the designed speed profile. We show that our proposed method gives a better solution than the conventional method in term of reducing the length of WPT system under the same operational constraints of EV and battery.

Wayside System Design for Dynamic Wireless Power Transfer Suitable for Direct Connected to a Constant Voltage Power Source

KODAI TAKEDA

Even though growing of a driving range of Electric vehicle (EV) is propelled by an improvement of lithium-ion battery and increase in the amount of it, the range is not long enough for inter-city transportation. Thus, dynamic wireless power transmission, which enables EV to get electricity from the ground without any connection and to drive more, has been proposed and improved. Because the system should be so long that it can charge EV sufficiently, it must be sturdy and simple. Therefore, ground facilities with LCC compensation network which is useful for DWPT are investigated in this study.

In previous studies, a design method of LCC compensation network was proposed, but the method did not ensure that power is transferred highly efficiently. Moreover, evaluation of the performance of DWPT system with LCC and design of the LCC network based on an analysis of power loss of coils which are connected to a voltage source in parallel has not been sufficiently done.

In this study, a novel design method of LCC network is proposed, and it achieves an improvement of efficiency and a designed specific output power. Furthermore, to save consumption of energy when no car is on the DWPT system, a control strategy of a multi-level inverter is proposed and verified that it saves considerable energy.

Magnetic Levitation - Linear Drive

Design and Control of Magnetically Levitated Permanent Magnetic Linear Motor as A Conveyor System

Salman. Ahmed

Magnetically levitated transport carrier systems have the potential of being extensively used in fields such as precision machinery, semiconductor fabrication, factory conveyance etc. in the future. Since these applications require high precision, magnetic levitation can provide complete contactless motion without the inherent presence of friction due to linear bearings allowing higher precision performance as well low wear and tear. However, magnetically levitated carriers suffer from high control complexity and expensive hardware, since replacement of linear bearings puts a 5 DOF control requirement on it. For that a conventional magnetically levitated carrier always has more actuators than required DOF i.e. 6 to 7 electromagnets controlling heave z, guidance y, pitch y, roll x and yaw z. Owing to the unstable nature of electromagnetic levitation, these DOF request active stabilization which increases the hardware, cost and control complexity. Furthermore, literature shows that for structural integrity, generally magnetically levitated carriers have bulky frames and require extra non-magnetic material which increases carrier weight and reduce effective loading capacity.

Overcoming these problems, we are developing a novel 6 DOF compact carrier comprising of a magnetically levitated transverse flux permanent magnet linear synchronous motor. The proposed structure is compact with almost entire volume composed of magnetic cores, orthogonally arranged and used for either thrust production or levitation. For a six DOF motion, only four actuators are employed for thrust, pitch, roll and heave active control and by virtue of the proposed motor, yaw and lateral motion are passively stabilized.

Energy and Electric Drive Control of Railway Vehicle

Railway Power Management by Integrated Design of Energy-saving Driving Strategy, Smart Train Scheduling, and Active Use of Energy Storage

Warayut Kampeerawat

In this study, an approach of power management in urban railway system (DC railway system) is proposed. The proposed method aims to provide an improvement of energy-saving operation by combining the design of driving strategy, train scheduling, and use of Energy Storage System. Basically, the design of driving strategy provides efficient energy-saving operation of each train and the design of train scheduling provides effective regenerative power usage among trains. However regenerative power can be utilized by exchanging among trains. There is considerable amount of surplus regenerative power. To manage surplus regenerative power, energy storage system is installed at suitable location with optimal capacity. By integrated design of software and hardware approach, power management can be more flexible and effective leading to increment of usable regenerative power. The numerical case study of Bangkok Rapid Transit System was performed and evaluated as a preliminary process for developing the proposed method. The numerical results showed that the improvement of energy-saving operation can be achieved.

Design of a convenient urban railway system by effective introduction of rapid trains with minimal modification to track infrastructure

KAZUKI AWAKI

Coming soon...

Evaluation of energy-saving automatic train operation by increasing acceleration of a train for a linear-metro

SHOTA MIYOSHI

Coming soon...

Wave Generator

Efficient design method of transverse flux type linear wave power generator using two-dimensional magnetic field analysis and response surface methodology

SEIGO WAKUI

Existing design method of wave power generator adopted three-dimensional magnetic field analysis, which it took a lot of time to calculate a magnetic flux. Adopting existing control method of wave power generator, generators canft generate electricity when the detent force requested is larger than the limitation. So I suggest the efficient design method of transverse flux type linear wave power generator using two-dimensional magnetic field analysis and response surface methodology through this research. Two-dimensional magnetic field analysis saves us a lot of time to calculate a magnetic flux and response surface methodology makes it possible to optimize the structure of a generator by a small number of simulations. Through simulations on JMAG, two things are showed. One is that there is little difference between the thrust constant calculated by two-dimensional magnetic field analysis and the three one. The other is that a new generator whose thrust constant is larger than the previous one is designed using the proposed method.