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Advanced Electrical Systems Theory (Hikihara Lab)

1. Target

As you already know, electricity basically behaves in two ways — "direct current" (DC) and "alternating current" (AC). If we look around us we find that electricity in homes is generally delivered over wires that carry an AC current at 100 V and 60 Hz (or 50 Hz in the Kanto region). On the other hand, PCs are powered by DC currents. In the case of a notebook computer, electric power flows along the power cable from the socket on the wall of your home to the battery of the computer. In this case, however, power must be converted from AC to DC. This process of converting electricity into the desired form to power a particular device is known as "electric power conversion." These days, all of us use this kind of conversion on a daily basis. In addition, consider the trains that we all take every day. To ensure more comfortable travel for passengers, the speed of trains is controlled using inverters, which convert DC into AC. This is one example of electric power conversion. Power conversion is a basic technology that is used all around us almost anywhere we care to look.

2. Initiatives of this lab

The technology of the 21st century is seeing rapid advances in many different fields, including bio- and nanotechnology, energy, and the environment. Supporting these fields are technologies for supplying energy and electric power and technologies for processing information. One technology that is becoming increasingly important is electric power conversion and system control technology, for supplying power in the necessary form (DC, AC) and quantity (50 W, 50 kW), and achieving the desired control objectives (e.g., maximizing battery life, maintaining a constant train speed).

RFIn our lab we pursue research into electric power conversion and system control engineering on a daily basis, with the aim of applying it to a variety of technical fields, including those listed above. Specifically, we study power conversion circuits such as dc-dc converters to convert DC into DC, we develop power conversion circuits using wide-bandgap semiconductors known as silicon carbide (SiC), we conduct R&D into power conversion devices such as SVCs and DC power transmission systems with a view to introducing them into electric power networks (large-scale electric circuits for supplying electricity under load from power plants to homes, factories, etc., over transmission lines and distribution lines) and into distributed power supplies such as photovoltaic generators and redux-flow secondary cells. We perform basic research into the operation of electric power networks featuring power conversion and system control technology, we conduct research on control technology for microsystems associated with nanotechnology, and we conduct mathematical research on nonlinear dynamics closely connected with power conversion and system control technology. In this way, we pursue power conversion and system control research that extends from the empirical to the theoretical and spans a broad range of scientific disciplines, from electrical and electronic engineering, and mechanical engineering, to mathematics, physics, and chemistry. If you are interested, please visit our home page.

Academic Staff


Takashi HIKIHARAProfessor (Graduate School of Engineering)

Research Interests

  • Nonlinear dynamics
  • Electric Energy Engineerig (Power electronics, Power network system)
  • Microelectro-Mechanical System (MEMS)


Katsura Bld. A1 Rm. 414
TEL: +81-75-383-2237
FAX: +81-75-383-2238
E-mail: hikihara + "@"+ kuee.kyoto-u.ac.jp

Introduction to R&D Topics

Nonlinear dynamics, nonlinear circuits, nonlinear systems theory

  1. Analysis of nonlinear dynamical systems: Time-delay systems, distributed systems, Hamilton systems
  2. Chaos control, behavior of multi-degree-of-freedom systems, analysis of synchronization phenomena
  3. Ginzburg-Landau equation analysis
  4. Analysis and control of hybrid systems

Applications of power devices and MEMS

  1. Switching circuit operational mode analysis and control
  2. Power device modeling for application to power converter circuit
  3. Development of MEMS based on nonlinear dynamics

Electrical energy networks

  1. Analysis and control of secondary battery cell operation
  2. Design and control of distributed electric power networks through power conversion
  3. Analysis and control of electric power networks based on hybrid systems