Patent ID: 11967908
Assignee: ABB SCHWEIZ AG
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A method for controlling an electrical converter system, the method comprising:
determining a nominal pulse pattern (tp,i*, Δup,i) and a reference trajectory (x*) of at least one electrical quantity of the electrical converter system over a horizon of future sampling instants, wherein the nominal pulse pattern (tp,i*, Δup,i*) and the reference trajectory (x*) are determined from a table of optimized pulse patterns, the nominal pulse pattern (tp,i*, Δup,i*) comprises switching transitions (Δup,i*) between output voltages of an electrical converter of the electrical converter system, and the reference trajectory (x*) indicates a desired future development of an electrical quantity of the converter system;
determining a small-signal pulse pattern (ũabc(t, λp,i)) by minimizing a cost function, wherein the cost function includes a small-signal error, wherein the small-signal error is based on a difference of the reference trajectory (x*) and a predicted trajectory (x), wherein impulse strengths (λp,i) of the small-signal pulse pattern (ũabc(t,λp,i)) encode a voltage-time value at each switching transition of the nominal pulse pattern (tp,i*, Δup,i*), and wherein the predicted trajectory (x) is determined over the horizon from measurements (i, vc, ig) in the converter system and from a model of the converter system, into which a sum of the nominal pulse pattern (tp,i*, Δup,i*) and small-signal pulse pattern (ũabc(t,λp,i)) are input;
determining a modified pulse pattern (topt,p,i, Δup,i) by moving the switching transitions of the nominal pulse pattern (tp,i*, Δup,i*) to generate modified switching transitions, wherein a switching transition is moved by a time interval, such that the time interval times a direction of the switching transition equals the voltage-time value that the impulse strength (λp,i) encodes at a nominal switching transition of the nominal pulse pattern (tp,i*, Δup,i*); and
applying at least a next switching transition of the modified pulse pattern (topt,p,i, Δup,i) to the electrical converter system.