A power converter for three-phase AC, comprising AC input terminals, three AC input terminals being disposed for one corresponding phase (U, V, W) on a three-phase AC input side, reactors connected to the respective AC input terminals, further comprising AC output terminals, each one of the AC output terminals being disposed for one corresponding phase on a three-phase AC output side, and clusters (u-a, v-a, w-a, u-b, v-b, w-b, u-c, v-c, w-c) comprising single-phase full-bridge converters, wherein each single-phase full-bridge converter includes a DC capacitor, wherein the single-phase full-bridge converters of a cluster are connected in series between an input side of the cluster and an output side of the cluster, wherein the clusters form groups of three clusters, wherein each cluster of a group is connected via a reactor to a different AC input terminal than the other two clusters of the group, and wherein the clusters of a group are connected to the same AC output terminal, wherein the power converter comprises: a circulating current controller an AC input/output current controller configured to control current on the three-phase AC input side to follow an AC input current command value and controlling current on the three-phase AC output side to follow an AC output current command value; characterized in that the power converter comprises: an effective power controller (13, B6) configured to control effective power flowing in the power converter from the three-phase AC input side so that a whole DC capacitor voltage average value obtained by averaging voltages of all the DC capacitors in the power converter follows a predetermined DC capacitor voltage command value; and a DC capacitor voltage balancing controller (21, B7, B8, B9) configured to generate a command value for the circulating current in order to control the circulating current circulating in the power converter so that each of inner-cluster DC capacitor voltage average values obtained by averaging voltage values of the DC capacitors of the respective clusters follows the whole DC capacitor voltage average value; and the circulating current controller (11, B10) configured to control the circulating current circulating in the power converter to follow the predetermined circulating current command value obtained by the DC capacitor voltage balancing controller (21, B7, B8, B9), such that control of the circulating current controller does not interfere with control of AC input/output current controller. a circulating current controller an AC input/output current controller configured to control current on the three-phase AC input side to follow an AC input current command value and controlling current on the three-phase AC output side to follow an AC output current command value; characterized in that the power converter comprises: an effective power controller (13, B6) configured to control effective power flowing in the power converter from the three-phase AC input side so that a whole DC capacitor voltage average value obtained by averaging voltages of all the DC capacitors in the power converter follows a predetermined DC capacitor voltage command value; and a DC capacitor voltage balancing controller (21, B7, B8, B9) configured to generate a command value for the circulating current in order to control the circulating current circulating in the power converter so that each of inner-cluster DC capacitor voltage average values obtained by averaging voltage values of the DC capacitors of the respective clusters follows the whole DC capacitor voltage average value; and the circulating current controller (11, B10) configured to control the circulating current circulating in the power converter to follow the predetermined circulating current command value obtained by the DC capacitor voltage balancing controller (21, B7, B8, B9), such that control of the circulating current controller does not interfere with control of AC input/output current controller. an effective power controller (13, B6) configured to control effective power flowing in the power converter from the three-phase AC input side so that a whole DC capacitor voltage average value obtained by averaging voltages of all the DC capacitors in the power converter follows a predetermined DC capacitor voltage command value; and a DC capacitor voltage balancing controller (21, B7, B8, B9) configured to generate a command value for the circulating current in order to control the circulating current circulating in the power converter so that each of inner-cluster DC capacitor voltage average values obtained by averaging voltage values of the DC capacitors of the respective clusters follows the whole DC capacitor voltage average value; and the circulating current controller (11, B10) configured to control the circulating current circulating in the power converter to follow the predetermined circulating current command value obtained by the DC capacitor voltage balancing controller (21, B7, B8, B9), such that control of the circulating current controller does not interfere with control of AC input/output current controller.