A method for operating a converter circuit is specified with the converter
circuit having a converter unit with a multiplicity of controllable power
semiconductor switches and having an energy storage circuit formed by two
series-connected capacitors, in which the controllable power
semiconductor switches are controlled by means of a control signal formed
from a hysteresis signal vector (x), and the hysteresis signal vector (x)
is formed from a difference-phase connection current vector
(.DELTA.i.sub.fi,i) by means of a hysteresis regulator, and the
difference-phase connection current vector (.DELTA.i.sub.fi,i) is formed
from the subtraction of a phase connection current vector (i.sub.fi,i)
from a reference phase connection current vector (i.sub.fi,i,ref), with
the reference phase connection current vector (i.sub.fi,i,ref) being
formed from a difference power value (P.sub.diff), a difference
wattless-component value (Q.sub.diff) and a phase flux vector
(.psi..sub.g,.alpha..beta.). In order to very largely stabilize the
switching frequency of the controllable power semiconductor switches, a
current correction value (i.sub.0) is additionally subtracted in order to
form the difference-phase connection current vector (.DELTA.i.sub.fi,i),
with the current correction value (i.sub.0) being formed by integration
of a phase connection voltage mean value (u.sub.inv,A), and the phase
connection voltage mean value (u.sub.inv,A) being formed by determining
the arithmetic mean value of the phase connection voltages (u.sub.inv,iM)
with the reference point of the connection point of the capacitors in the
energy storage circuit. A device is also specified, by means of which the
method can be carried out in a particularly simple manner.