| Abstract |
Reliable AC back-up fed by a battery source are in a continuous evolution. The market's need drove us hard to develop a new topology of DC/DC converter integrated in a full digital control inverter. This new technical approach has been implemented over an inverter range. It has been done at rst on a 2U'/1kVA unit and a 1U'/300VA unit both naturally cooled as well as a 3kVA unit forced air of 2 U'height, outputting 120 Vac or 230 Vac. In the power inverter field, one of the best way to get the proper AC availability level is to increase the MTBF1 of the unit. Well-known means to improve
the MTBF are the decreasing of part-count number and a lower working temperature, actually
the challenge is to get the higher possible efficiency. A more than 90% overall efficiency has been achieved with a new isolated DC/DC converter called the "Symmetrical Flux Forward"(SFF), stepping up the input voltage from a low voltage to 350 Vdc. This improved topology has a very low part-count and many other advantages. The low part-count condition has been fulfilled too by applying the most recent technologies in an inverter. In fact, digital signal processing (DSP) and eld programmable gate array (FPGA) technologies become a possible and interesting solution to overcome the inverter control barrier. Closing all control feedback loops in the digital signal processor gives us also a temperature dependency compensation of analog devices, a very low part count, an efficient active filtering to comply with standard and an automatic board self-checking at the manufacturing time. This paper presents the state of the art in the inverter technology and a new DC/DC converter topology leading to a smart AC inverter solution. |
