# US 9,882,463 B2 · In or relating to chain-link converters > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,882,463 B2 - Document ID: US9882463B2 - Status: Granted - Kind: B2 - Application number: 15/309,398 - Filed: 2015-05-12 - Published: 2017-03-16 - Granted: 2018-01-30 - Earliest claimed: 2014-05-12 - Assignees: General Electric Technology GmbH - Applicants: General Electric Technology GmbH - Inventors: Timothy James Stott; Francisco Jose Moreno Muñoz; Philip Robin Couch - Web page: https://patentgrep.com/patent/US9882463B2 ## CPC - G01R 31/50: Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections (testing of sparking plugs H01T13/58) - H02M 1/088: for the simultaneous control of series or parallel connected semiconductor devices - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 7/483: Converters with outputs that each can have more than two voltages levels - H02M 7/4835: {comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage} - H02M 1/0003: {Details of control, feedback or regulation circuits} - H02M 1/325: {with means for allowing continuous operation despite a fault, i.e. fault tolerant converters} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - 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 of identifying a faulty sub-module of a chain-link converter is provided, wherein the chain-link converter includes a plurality of sub-modules with each sub-module including at least one switching element and an energy storage device which together are selectively operable to provide a voltage source. The method comprises the steps of: measuring a switching characteristic of each sub-module of the chain-link converter; establishing a switching characteristic signature of the chain-link converter; and identifying the or each sub-module with a switching characteristic that deviates from the switching characteristic signature as being a faulty sub-module. ## Claims ### Claim 1 A method of identifying a faulty sub-module of a chain-link converter, the chain-link converter including a plurality of sub-modules, each sub-module including at least one switching element and an energy storage device which together are selectively operable to provide a voltage source, the method comprising the steps of: measuring a switching characteristic of each sub-module of the chain-link converter; establishing a switching characteristic signature of the chain-link converter; and identifying the or each sub-module with a switching characteristic that deviates from the switching characteristic signature as being a faulty sub-module; wherein the step of measuring a switching characteristic of each sub-module of the chain-link converter includes measuring a switching frequency of each sub-module of the chain-link converter; the step of establishing a switching characteristic signature of the chain-link converter includes establishing a switching frequency signature of the chain-link converter from the measured switching frequencies; and the step of identifying the or each sub-module with a switching characteristic that deviates from the switching characteristic signature as being a faulty sub-module includes identifying the or each sub-module with a switching frequency that deviates from the switching frequency signature. ### Claim 2 (depends on 1) The method according to claim 1 wherein: the step of measuring a switching characteristic of each sub-module of the chain-link converter includes measuring for each sub-module of the chain-link converter a switching duration between the sub-module providing a voltage source and not providing a voltage source; the step of establishing a switching characteristic signature of the chain-link converter includes establishing a switching duration signature of the chain-link converter; and the step of identifying the or each sub-module with a switching characteristic that deviates from the switching characteristic signature as being a faulty sub-module includes identifying the or each sub-module with a switching duration that deviates from the switching duration signature. ### Claim 3 (depends on 1) The method according claim 1 wherein the switching characteristic signature takes the form of a signature distribution of sub-module switching characteristics. ### Claim 4 (depends on 3) The method according to claim 3 wherein the step of identifying the or each sub-module with a switching characteristic that deviates from the switching characteristic signature includes identifying the or each sub-module with a switching characteristic that lies outside the signature distribution of sub-module switching characteristics. ### Claim 5 (depends on 3) The method according to claim 3 wherein the signature distribution of sub-module switching characteristics is defined by a range of switching characteristic values. ### Claim 6 (depends on 3) The method according to claim 3 wherein the signature distribution of sub-module switching characteristics includes only those switching characteristic sub-ranges which together form a main cluster. ### Claim 7 (depends on 1) The method according to claim 1 wherein the step of measuring a switching characteristic of each sub-module includes representing visually the distribution of sub-module switching characteristics of all sub-modules within the chain-link converter. ### Claim 8 (depends on 1) The method according to claim 1 wherein the switching characteristic signature takes the form of an average switching characteristic of all the sub-modules in the chain-link converter. ### Claim 9 (depends on 8) The method according to claim 8 wherein the step of identifying the or each sub-module with a switching characteristic that deviates from the switching characteristic signature includes identifying the or each sub-module with a switching characteristic that differs from the average switching characteristic of all the sub-modules in the chain-link converter by a threshold amount or more. ### Claim 10 (depends on 9) The method according to claim 9 wherein the threshold amount is established according to operating conditions of the chain-link converter. ### Claim 11 (depends on 1) The method according to claim 1 further including the step of signalling an alarm condition when a faulty sub-module is identified. ### Claim 12 (depends on 1) The method according to claim 1 wherein measuring a switching characteristic of each sub-module of the chain-link converter includes establishing for each sub-module an average switching characteristic over a predetermined time period. ### Claim 13 (depends on 1) The method according to claim 1 further including the step of comparing the switching characteristic signature of the chain-link converter with the switching characteristic signature of at least one other chain-link converter within the same voltage source converter. ### Claim 14 (depends on 1) The method according to claim 1 further including the step of comparing the switching characteristic signature of the chain-link converter with a reference switching characteristic signature. ### Claim 15 (depends on 1) The method according to claim 1 wherein the switching characteristic signature comprises a switching characteristic threshold, and the method further comprises: comparing the switching characteristic with a switching characteristic threshold, and identifying the or each sub-module for which the switching characteristic exceeds the switching characteristic threshold as being a faulty sub-module. ### Claim 16 A controller for a chain-link converter, the chain-link converter including a plurality of sub-modules, the controller configured to: measure a switching frequency characteristic of each sub-module of the chain-link converter; establish a switching characteristic signature of the chain-link converter; and identify the or each sub-module with a switching characteristic that deviates from the switching characteristic signature as being a faulty sub-module; wherein measuring a switching characteristic of each sub-module of the chain-link converter includes measuring a switching frequency of each sub-module of the chain-link converter; establishing a switching characteristic signature of the chain-link converter includes establishing a switching frequency signature of the chain-link converter from the measured switching frequencies; and identifying the or each sub-module with a switching characteristic that deviates from the switching characteristic signature as being a faulty sub-module includes identifying the or each sub-module with a switching frequency that deviates from the switching frequency signature. ### Claim 17 (depends on 1) A non-transitory computer readable medium comprising a computer program that when executed by a processor, causes the processor to perform the method of claim 1.