Title :
All digital controlled three-phase UPS without inverter-transformer
Author :
Kanouda, Akihiko ; Sakurai, Yoshimi ; Kubo, Kenji ; Shimada, Keizou ; Kunisada, Hideaki ; Umetsu, Hideyasu
Author_Institution :
Res. Lab., Hitachi Ltd., Ibaraki, Japan
Abstract :
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
Keywords :
DC-AC power convertors; PWM invertors; digital control; harmonic distortion; microcomputer applications; power engineering computing; power system harmonics; reduced instruction set computing; uninterruptible power supplies; voltage control; DC voltage stabilizer; RISC microcomputers; digital control scheme; input current harmonics; inverter; nonlinear load; output voltage harmonics; three-phase UPS; total harmonic distortion; transformerless circuit; uninterruptible power system; Bridge circuits; Capacitors; Computer aided instruction; Digital control; Harmonic distortion; Microcomputers; Pulse width modulation inverters; Reduced instruction set computing; Uninterruptible power systems; Voltage control;
Conference_Titel :
Power Conversion Conference - Nagaoka 1997., Proceedings of the
Conference_Location :
Nagaoka
Print_ISBN :
0-7803-3823-5
DOI :
10.1109/PCCON.1997.638390
