Method of controlling electric valves of a converter

A method for controlling electric valves of a converter which has at least one valve or one valve chain per AC phase, comprising the steps of:

• a) driving the valves or valve chains of each AC phase with a mutual phase shift, and
• b) commutating the valves of the converter to regulate current output of the converter using control signals generated as a function of a commutation function KF.sub.ij (t), where:
• ##EQU6## wherein t=time, m.sub.i (t)=modulation function, n=control variable with 1.ltoreq.n.ltoreq.n1, n1=accuracy characteristic, i=control variable for characterizing the AC phase with 1.ltoreq.i.ltoreq.A.PHI..multidot.AG, A.PHI.=number of valve chains with fundamental-wave shift, AG=number of valve chains having the same fundamental-wave phase, j=control variable for characterizing a pulse pattern with 1.ltoreq.j.ltoreq.A.epsilon..multidot.A.PHI., A.epsilon.=number of independent valve chains with shifted pulse pattern, k=multiplicity of timing, .omega.=angular frequency of the AC voltage, .PHI..sub.i =prescribable phase angle, .psi..sub.i =controller correction angle, and .epsilon..sub.j =initial value of the jth pulse pattern of the valve chain circuit with the same index i.