New type UPS 'BIROS-X'

A new uninterruptible power system (UPS), called BIROS-X, is described which is highly intelligent, small in size, and highly efficient. The noise level of the BIROS-X is very low, using the technology of inaudible high frequency pulse width modulation (PWM) control. Higher efficiency is achieved by using insulated gate bipolar transistors (IGBTs) in the inverter and the rectifier. The inverter is a full-bridge circuit of four IGBTs which switch at 9.6 kHz with a modulated width of a sine wave. As a result of the high-frequency switching of the IGBTs, the AC filter size is now 10% compared with those of four conventional UPSs. The rectifier consists of 6 IGBTs which switch at 16 kHz to make the input current sinusoidal and to make the power factor 98% at the full load, with a distortion factor of less than 10%. Due to various sealed lead-acid batteries which may be used for the UPS, newly devised charging methods can be adapted for each case. The functions of the operation panel include metering, operation guidance (starting up, switching off, a maintenance bypass switch), and an alarm indicator.<>