Other

Tohoku University

Tetsuo Sasaki

Masahiko Tanimoto

Yoshio Izui

Jun-ichi Nishizawa

Ken Suto

Yoshihiro Hasegawa

Naoto Fukuta

Tomoyuki Kimura

Kenji Iba

Yasuyuki Kowada

Masatoshi Okubo

Tadao Tanabe

Kenichi Deno

An electromagnetic wave generator encompasses a first pump beam emitter () configured to emit a first pump beam (hv) having a wavelength larger than one micrometer; a second pump beam emitter () configured to emit a wavelength-tunable second pump beam (hv) having a wavelength larger than one micrometer, the wavelength of which is different from the wavelength of the first pump beam (hv); a nonlinear optical crystal () configured to generate an electromagnetic wave (hv) of a difference frequency between the first pump beam (hv) and second pump beam (hv); and an optical system (M, M) configured to irradiate the first pump beam (hv) and second pump beam (hv) to the nonlinear optical crystal (), by adjusting an external intersection angle between the first pump beam (hv) and second pump beam (hv) within 0.5&#xb0; at the difference frequency of 1 THz. Here, a frequency-tunable terahertz electromagnetic wave (hv) is generated in the nonlinear optical crystal (), by changing the frequency of the second pump beam (hv), being liked with the change of the external intersection angle.

Electromagnetic wave generating device

A power system stabilization system is provided between power generation equipment significantly fluctuating in output and a power system required to maintain a predetermined voltage. In the power system stabilization system, a voltage detection device and a current detection device detect voltage and current, respectively, of the power system and voltage and current thus detected are used to calculate a level of active power required and that of reactive power required which are referred to to provide charging and discharging from a rechargeable battery to the power system via an A-D converter.

Power system stabilization system and method employing a rechargeable battery system

A desired value of reactive power flow between a to-be-controlled power system and an adjoining power system is determined according to measured values of the reactive power flow and an effective power flow and desired voltage values of the to-be-controlled power system and of the adjoining power system. Thereafter, a required value of a reactive power of the to-be-controlled power system is calculated according to the desired value of the reactive power flow, the measured values of the reactive power flow and the effective power flow, and the desired voltage value and a measured voltage value in the to-be-controlled power system. Thereafter, a control apparatus having an electric capacity near to the required value of the reactive power is selected from control apparatus arranged in the to-be-controlled power system to make the selected control apparatus adjust a voltage of the to-be-controlled power system. Therefore, cooperation of the to-be-controlled power system with the adjoining power system can be performed by collecting locally-existing-information, and a voltage fluctuation and/or a reactive power fluctuation in the to-be-controlled power system can be immediately suppressed.

Power system control apparatus and power system control method

Growing community of inventors

Osaka, Japan

Tetsuo Sasaki