| 摘要 |
PROBLEM TO BE SOLVED: To obtain the reduction of a switching loss and the distortion reduction of an AC output current.SOLUTION: A power conversion device 1A interconnecting to a commercial power system 3 includes: a three-phase three-level inverter unit 10 which converts DC power into AC power; and a control unit 20A of a hysteresis comparator method which controls phase-by-phase an output current to range within a predetermined hysteresis width to a sine wave current instruction value. The control unit 20A has a forcible switching stop control function for forcibly switching phase-by-phase a switching element in the three-phase inverter unit only during a predetermined period which includes the time points of the positive and negative peak values of the current instruction value. The control unit 20A performs forcible switching stop control when a system voltage vector reaches a region exceeding a hexagram boundary in a spatial vector coordinate system of the three-phase inverter unit, whereas does not perform the forcible switching stop control when the system voltage vector reaches a region within the hexagram boundary.SELECTED DRAWING: Figure 1 |
