A power converter , which is built in a power generator , the power converter being connected to a rotating electrical machine including a field winding and a plurality of sets of armature windings and being configured to convert AC power generated by the rotating electrical machine into DC power, the power converter comprising: a field power conversion section for controlling a field current flowing in the field winding ; an armature power conversion section comprising bridge circuits (UH, UL, VH, VL, WH, WL; XH, XL, YH, YL, ZH, ZL), the bridge circuits being provided correspondingly to the plurality of sets of armature windings and each comprising switching elements of a positive arm (31, 32, 33; 41, 42, 43) and switching elements of a negative arm (34, 35, 36; 44, 45, 46); characterised by comprising: a control section configured to, when it is detected that a voltage between a B-terminal and an E-terminal as input and output terminals of the power generator has exceeded a first predetermined voltage value: turn on all the switching elements the negative arm (UL, VL, WL) or the positive arm (UH, VH, WH) of the bridge circuit connected to a part of the plurality of sets of armature windings and turn off all the switching elements (31, 32, 33; 41, 42, 43, 44, 45, 46) of the positive arm (UH, VH, WH) or the negative arm (UL, VL, WL) that is paired with the respective negative arm (UL, VL, WL) or the respective positive arm (UH, VH, WH); reduce the field current flowing in the field winding to start an operation of reducing load dump energy; and thereafter turn off all the turned-on switching elements when a predetermined condition is satisfied. a field power conversion section for controlling a field current flowing in the field winding ; an armature power conversion section comprising bridge circuits (UH, UL, VH, VL, WH, WL; XH, XL, YH, YL, ZH, ZL), the bridge circuits being provided correspondingly to the plurality of sets of armature windings and each comprising switching elements of a positive arm (31, 32, 33; 41, 42, 43) and switching elements of a negative arm (34, 35, 36; 44, 45, 46); characterised by comprising: a control section configured to, when it is detected that a voltage between a B-terminal and an E-terminal as input and output terminals of the power generator has exceeded a first predetermined voltage value: turn on all the switching elements the negative arm (UL, VL, WL) or the positive arm (UH, VH, WH) of the bridge circuit connected to a part of the plurality of sets of armature windings and turn off all the switching elements (31, 32, 33; 41, 42, 43, 44, 45, 46) of the positive arm (UH, VH, WH) or the negative arm (UL, VL, WL) that is paired with the respective negative arm (UL, VL, WL) or the respective positive arm (UH, VH, WH); reduce the field current flowing in the field winding to start an operation of reducing load dump energy; and thereafter turn off all the turned-on switching elements when a predetermined condition is satisfied. turn on all the switching elements the negative arm (UL, VL, WL) or the positive arm (UH, VH, WH) of the bridge circuit connected to a part of the plurality of sets of armature windings and turn off all the switching elements (31, 32, 33; 41, 42, 43, 44, 45, 46) of the positive arm (UH, VH, WH) or the negative arm (UL, VL, WL) that is paired with the respective negative arm (UL, VL, WL) or the respective positive arm (UH, VH, WH); reduce the field current flowing in the field winding to start an operation of reducing load dump energy; and thereafter turn off all the turned-on switching elements when a predetermined condition is satisfied. <EOS>