New Single-Phase UPS Converter

In the course of current technological progress, the power ratings of minicomputer systems which require an uninterruptible power supply have been generally decreasing. At the same time, the computing capacity of the units has greatly increased. Consequently the demand for computer-aided systems for development, design, manufacturing and management has risen enormously, even for applications in smaller and middle-sized companies. In addition, microprocessor systems (whose power ratings are inherently small) are being increasingly applied for process control and monitoring in industrial plants. Most of these small units are decentrally located, and hence are most advantageously supplied by separate, independent power systems. The ratings of these units lie in the range of about 1 kVA to 10 kVA. In response to this development in demand, a new series of single-phase UPS systems is being offered, with ratings of 3, 5, and 10 kVA. These units are characterized by maximum operating reliability, simple design, and very fast output voltage regulation. In addition, the inverter is insensitive to the highly distorted load currents which are typical of computer power supplies having non-linear characteristics. The new UPS systems also have a low noise level, so that they can be conveniently installed in offices, even next to the computer. Modern, rational manufacturing methods are used, and consequently this high quality equipment can be offered at reasonable prices. Fig. 1 shows a 5 kVA-UPS.