| 摘要 |
PROBLEM TO BE SOLVED: To solve the problems in which: when switching from a highly efficient single-arm mode in which either of an upper arm switching element and a lower arm switching element is activated to a highly controllable both-arm mode in which both switching elements are activated to be capable of performing step-down and step-up, cutting-down of carrier frequency is performed so that mode switching to both-arm mode is likely to be delayed; and if switching to both-arm mode is performed in advance, efficiency is declined.SOLUTION: In an electrical power system, mode conversion means of a controller 24 predicts, based on reactor current ILs detected by a current sensor 28 and carrier frequency after reduction processing, the minimum value ILmin_e of the reactor current IL at the time of stepping up in the one direction voltage conversion mode, and the maximum value ILmax_e of the reactor current IL at the time of stepping down in the one direction voltage conversion mode. When the plus/minus sign of the predicted maximum value ILmax_e or the minimum value ILmin_e is different from that of the detected reactor current ILs, the mode conversion means switches a conversion mode from the one direction voltage conversion mode to the bidirectional voltage conversion mode.SELECTED DRAWING: Figure 2 |
