Yoshimi Sakurai

Instantaneous control method with a GTO converter for active and reactive powers in superconducting magnetic energy storage

A novel GPG (gate pulse generator) for gate-turn-off converters (GTOs) is presented that provides quick-response firing-angle control and pulse width-modulated (PWM) control. Using the GPG, instantaneous control of active and reactive powers for an SMES (superconducting magnetic energy storage) system using one GTO converter is studied.<<ETX>>

Instantaneous control method with a GTO converter for active and reactive powers in superconducting magnetic energy storage. [Gate Turn Off]

A new type of GPG (gate pulse generator) is presented to give GTO converters quick response firing angle control and PWM control functions. Using the GPG, an instantaneous control method of active and reactive powers for an SMES (superconducting magnetic energy storage) employing one GTO converter is studied.

All digital controlled three-phase UPS without inverter-transformer

A fully digital-controlled three-phase UPS (uninterruptible power system) is developed which does not have an inverter-transformer. To remove the transformer, a different type of main circuit from the conventional UPS is adopted. One phase of the input AC is regarded as the common voltage of the main circuit. A DC voltage stabilizer solves problems caused when this transformerless circuit is applied to the UPS. A digital controller with two RISC (Reduced Instruction Set Computer) processing microcomputers to operate the circuit is also proposed. Experiments show the THD (total harmonic distortion) of the input current is less than 5%, and that of the output voltage is less than 3.6% under nonlinear load.