Development of miniaturized AC reactors with lower-losses using amorphous wound cores in 400-kVA UPS

We have designed and constructed lower-loss and smaller-unit volume three-phase amorphous reactors for use as filter components in a 400-kVA on-line UPS. For high-accuracy loss estimation, a simplified method has been applied that is based on measured B-H curves and iron losses of amorphous cores, modeled with magnetic simulations of a finite-element method (FEM) considering the directions of the amorphous ribbon planes. The reactors are formed from toroidal wound cores. Two core sizes designed with magnetic flux densities of standard (0.8 T) and higher (1.2 T) values are constructed. Their unit volumes are shrunk by 9 % and 43 %, respectively resulting in UPS efficiencies 0.54 % and 0.39 % higher than those of a conventional silicon-steel core reactor. The accuracy of the loss estimation method for PWM-induced reactors is verified. The method is confirmed to enable a miniaturized reactor for filtering in an inverter system to be designed on the basis of the trade-off with permissive raise of loss.