Abstract: Switching-nodes preset SPWM inverter is used in PWM mode AC / DC / AC power generating system; the inverter consists of the three-phase bridge, AC filter, neutral forming transformer and control and drive circuits. Insulated-gate bipolar transistor (IGBT) is a new kind of power electronic device, which is used to develop a 15kVA inverter. In this paper, the design considerations of the main parts of the converter are introduced, including the selection of switching nodes, the analysis of ACF and NFT, the forming of control circuit and the use of IGBT. On fully analysis and optical design of all the components, the developed inverter has the characteristics of small volume, light weight and high electric performance.

Key words: inverters, PWM, VSCF AC power, switching-nodes preset, 3-phase 4-line, IGBT