To provide a method for controlling a power converter operated in linkage with an AC power supply and the like.

A frequency command value of a power converter 5 is obtained by eliminating unbalanced components from an instantaneous value of the terminal voltage of a generator 2 by means of a waveform adjustor 51 and then adjusting the phase of a waveform command value obtained from the terminal voltage by means of AΦR 52. By controlling a power converter circuit 11 based on this frequency command value, the power converter 5 is readily allowed to follow the change in terminal voltage of the generator 2 and the change in frequency.