# US 10,312,793 B2 · Control of electrical converter based on optimized pulse patterns > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,793 B2 - Document ID: US10312793B2 - Status: Granted - Kind: B2 - Application number: 15/865,426 - Filed: 2018-01-09 - Published: 2018-05-10 - Granted: 2019-06-04 - Earliest claimed: 2015-07-09 - Assignees: ABB Schweiz AG - Applicants: ABB Schweiz AG - Inventors: Eduardo Rohr; Peter Al-Hokayem; Tobias Geyer - Web page: https://patentgrep.com/patent/US10312793B2 ## CPC - H02M 1/12: Arrangements for reducing harmonics from AC input or output - H02M 7/217: using semiconductor devices only - H02M 7/53873: {with digital control} - H02M 1/0012: {Control circuits using digital or numerical techniques (in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873)} - H02M 1/0038: {Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control} - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) ## Abstract A method for operating an electrical converter including: determining an optimized pulse pattern from a fundamental voltage reference for the electrical converter, wherein the optimized pulse pattern is determined from a first lookup table and includes discrete voltage amplitude values changing at predefined switching instants; determining a harmonic content reference from the fundamental voltage reference based on a second lookup table, wherein the harmonic content reference is a harmonic current reference determined from the frequency spectrum of a current of the electrical converter or the harmonic content reference is a filtered voltage reference determined by applying a first order frequency filter to a voltage, which current or voltage is generated, when the optimized pulse pattern is applied to the electrical converter; determining a harmonic content error from the harmonic content reference by subtracting an estimated output voltage and/or estimated output current of the electrical converter from the harmonic content reference; modifying the optimized pulse pattern by timeshifting switching instants such that the fundamental voltage reference is tracked and the harmonic content error is corrected by the timeshifted switching instants; applying the modified optimized pulse pattern to semiconductor switches of the electrical converter. ## Claims ### Claim 1 A method for operating an electrical converter, the method comprising: determining an optimized pulse pattern (v(t)) from a fundamental voltage reference (vctr1(t)) for the electrical converter, wherein the optimized pulse pattern (v(t)) is determined from a first lookup table and comprises discrete voltage amplitude values changing at predefined switching instants; determining a harmonic content reference (īh(t), ψ(t)) from the fundamental voltage reference (vctr1(t)) based on a second lookup table, wherein the harmonic content reference is a harmonic current reference (īh(t)) determined from the frequency spectrum of a current of the electrical converter or the harmonic content reference is a filtered voltage reference (ψ(t)) determined by applying a first order frequency filter to a voltage, which current or voltage is generated, when the optimized pulse pattern is applied to the electrical converter; determining a harmonic content error (ĩ(t), ψ(t)) from the harmonic content reference (īh(t), ψ(t)) by subtracting an estimated output voltage (ψ(t)) and/or estimated output current (i(t)) of the electrical converter from the harmonic content reference (īh(t), ψ(t)); modifying the optimized pulse pattern (v(t)) by timeshifting switching instants such that the fundamental voltage reference (vctr1(t)) is tracked and the harmonic content error (ĩ(t),{tilde over (ψ)}(t)) is corrected by the timeshifted switching instants; applying the modified optimized pulse pattern (v(t)) to semiconductor switches of the electrical converter. ### Claim 2 (depends on 1) The method of claim 1, wherein the harmonic content error (ĩ(t), {tilde over (ψ)}(t)) is corrected by minimizing a cost function, which comprises a term quadratic in the harmonic content error and/or a term quadratic in timeshifts of the switching instants. ### Claim 3 (depends on 2) The method of claim 2, wherein the timeshifts are applied in a time window ending at a prediction horizon; and/or wherein the cost function is based on the harmonic content error at the end of the prediction horizon. ### Claim 4 (depends on 3) The method of claim 3, wherein the cost function is minimized subject to the constraint that an order of switching instants does not change. ### Claim 5 (depends on 3) The method of claim 3, wherein the cost function is minimized by solving a quadratic programming. ### Claim 6 (depends on 3) The method of claim 3, further comprising: determining the fundamental voltage reference (vctr1(t)) from a fundamental current reference (ī1(t)) and an estimated grid voltage (υg). ### Claim 7 (depends on 3) The method of claim 3, wherein the harmonic content error ({tilde over (ψ)}(t)) is the difference of the filtered voltage reference (ψ(t)) and an estimated filtered voltage (ψ(t)); wherein the estimated filtered voltage (ψ(t)) is determined by online applying the first order frequency filter to the estimated output voltage of the electrical converter. ### Claim 8 (depends on 2) The method of claim 2, wherein the cost function is minimized subject to the constraint that an order of switching instants does not change. ### Claim 9 (depends on 8) The method of claim 8, wherein the cost function is minimized by solving a quadratic programming. ### Claim 10 (depends on 2) The method of claim 2, wherein the cost function is minimized by solving a quadratic programming. ### Claim 11 (depends on 2) The method of claim 2, further comprising: determining the fundamental voltage reference (vctr1(t)) from a fundamental current reference (ī1(t)) and an estimated grid voltage (υg). ### Claim 12 (depends on 2) The method of claim 2, wherein the harmonic content error ({tilde over (ψ)}(t)) is the difference of the filtered voltage reference (ψ(t)) and an estimated filtered voltage (ψ(t)); wherein the estimated filtered voltage (ψ(t)) is determined by online applying the first order frequency filter to the estimated output voltage of the electrical converter. ### Claim 13 (depends on 1) The method of claim 1, further comprising: determining the fundamental voltage reference (vctr1(t)) from a fundamental current reference (ī1(t)) and an estimated grid voltage (υg). ### Claim 14 (depends on 1) The method of claim 1, wherein the harmonic content error ({tilde over (ψ)}(t)) is the difference of the filtered voltage reference (ψ(t)) and an estimated filtered voltage (ψ(t)); wherein the estimated filtered voltage (ψ(t)) is determined by online applying the first order frequency filter to the estimated output voltage of the electrical converter. ### Claim 15 (depends on 1) The method of claim 1, wherein the fundamental voltage reference (vctr1(t)) is determined from a fundamental current reference (ī1(t)) and an error provided by an external controller. ### Claim 16 (depends on 1) The method of claim 1, wherein the optimized pulse patterns (v(t)) in the first lookup table have been calculated offline. ### Claim 17 (depends on 1) The method of claim 1, wherein the harmonic content references (īh(t), ψ(t)) in the second lookup table have been calculated offline from the corresponding optimized pulse patterns applied to a model of the electrical converter. ### Claim 18 A controller for an electrical converter, which controller is adapted for controlling the electrical converter, the controller operable to: determine an optimized pulse pattern (v(t)) from a fundamental voltage reference (vctr1(t)) for the electrical converter, wherein the optimized pulse pattern (v(t)) is determined from a first lookup table and comprises discrete voltage amplitude values changing at predefined switching instants; determine a harmonic content reference (īh(t), ψ(t)) from the fundamental voltage reference (vctr1(t)) based on a second lookup table, wherein the harmonic content reference is a harmonic current reference (īh(t)) determined from the frequency spectrum of a current of the electrical converter or the harmonic content reference is a filtered voltage reference (ψ(t)) determined by applying a first order frequency filter to a voltage, which current or voltage is generated, when the optimized pulse pattern is applied to the electrical converter; determine a harmonic content error (ĩ(t), {tilde over (ψ)}(t)) from the harmonic content reference (īh(t), ψ(t)) by subtracting an estimated output voltage (ψ(t)) and/or estimated output current (i(t)) of the electrical converter from the harmonic content reference (īh, ψ(t)); modify the optimized pulse pattern (v(t)) by timeshifting switching instants such that the fundamental voltage reference (vctr1(t)) is tracked and the harmonic content error (ĩ(t), {tilde over (ψ)}(t)) is corrected by the timeshifted switching instants; and apply the modified optimized pulse pattern (v(t)) to semiconductor switches of the electrical converter. ### Claim 19 (depends on 18) A converter system, comprising: an electrical converter; and a controller according to claim 18. ### Claim 20 (depends on 19) The converter system of claim 19, wherein the converter is a voltage source converter for converting an AC input voltage into a DC output voltage.