# US 12,113,433 B2 · System and method for detecting IGBT failure in a multi-level converter using gate-emitter voltage sensing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,113,433 B2 - Document ID: US12113433B2 - Status: Granted - Kind: B2 - Application number: 17/725,683 - Filed: 2022-04-21 - Published: 2023-10-26 - Granted: 2024-10-08 - Earliest claimed: 2022-04-21 - Assignees: GE Infrastructure Technology LLC - Applicants: General Electric Company - Inventors: Nathaniel Robert Michener; Robert Gregory Wagoner - Web page: https://patentgrep.com/patent/US12113433B2 ## CPC - H02M 1/32: Means for protecting converters other than automatic disconnection - H03K 17/08128: {in composite switches} - H02J 3/0012: characterised by the contingency detection means in AC networks, e.g. using phasor measurement units [PMU], synchrophasors or contingency analysis - H02M 1/084: using a control circuit common to several phases of a multi-phase system - H02M 5/4585: {having a rectifier with controlled elements} - H03K 17/18: Modifications for indicating state of switch - 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) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A method for operating a multi-level bridge power converter of an electrical power system connected to a power grid includes receiving a commanded state for one or more switching devices thereof. The method also includes receiving a gate-emitter voltage of one or more of the switching devices. Further, the method includes comparing, via at least one comparator, the gate-emitter voltage of the one or more switching devices to a reference voltage range corresponding to the commanded state of the one or more switching devices. In addition, the method includes determining an actual state of the one or more switching devices based on the comparison. Thus, the method also includes implementing a control action based on the actual state of the one or more switching devices. ## Claims ### Claim 1 A controller-implemented method for operating a multi-level bridge power converter of an electrical power system connected to a power grid, the multi-level power converter having a first converter coupled to a DC link, the multi-level power converter having a plurality of switching devices, the method comprising: receiving, via a controller, a commanded state for a gate of one or more of the plurality of switching devices; receiving, via the controller, a gate-emitter voltage of the one or more of the plurality of switching devices, the gate-emitter voltage referring to a voltage from the gate to an emitter of the one or more of the plurality of switching devices; comparing, via at least one comparator of the controller, the gate-emitter voltage of the one or more plurality of switching devices to a reference voltage range corresponding to the commanded state for the gate of the one or more of the plurality of switching devices; determining, via the controller, an actual state of the gate of the one or more of the plurality of switching devices based on the comparison; and implementing, via the controller, a control action based on the actual state of the gate of the one or more of the plurality of switching devices. ### Claim 2 (depends on 1) The method of claim 1, wherein the commanded state is one of an ON state or an OFF state of the gate. ### Claim 3 (depends on 2) The method of claim 2, wherein comparing the gate-emitter voltage of one or more of the plurality of switching devices to the reference voltage range corresponding to the commanded state for the gate of the one or more plurality of switching devices further comprises: comparing the gate-emitter voltage of the one or more plurality of switching devices to each of an ON reference voltage range corresponding to the ON state or an OFF reference voltage range corresponding to the OFF state via, at least, first and second comparators. ### Claim 4 (depends on 3) The method of claim 3, wherein determining the actual state of the gate of the one or more plurality of switching devices based on the comparison further comprises: if the commanded state for the gate of the one or more plurality of switching devices is the ON state, determining whether an output of the first comparator is within the ON reference voltage range and if so, then determining that the actual state of the gate of the one or more of the plurality of switching devices is the ON state. ### Claim 5 (depends on 3) The method of claim 3, wherein determining the actual state of the gate of the one or more plurality of switching devices based on the comparison further comprises: if the commanded state of the gate of the one or more plurality of switching devices is the OFF state, determining whether an output of the second comparator is within the OFF reference voltage range and if so, then determining that the actual state of the gate of the one or more of the plurality of switching devices is the OFF state. ### Claim 6 (depends on 3) The method of claim 3, wherein determining the actual state of the gate of the one or more plurality of switching devices based on the comparison further comprises: if the commanded state of the gate of the one or more plurality of switching devices is one of the ON state or the OFF state, determining whether an output of a third comparator is within a FAULT reference voltage range and if so, then determining that the actual state of the gate of the one or more of the plurality of switching devices is a FAULT state. ### Claim 7 (depends on 3) The method of claim 3, wherein the ON reference voltage range comprises voltages ranging between about +10 volts (V) and about +20 V. ### Claim 8 (depends on 3) The method of claim 3, wherein the OFF reference voltage range comprises voltages ranging between about −5V to about −20V. ### Claim 9 (depends on 3) The method of claim 3, wherein a FAULT reference voltage range comprises voltages ranging between about −3V to about +3V. ### Claim 10 (depends on 1) The method of claim 1, further comprising implementing a time delay after receiving the commanded state for the gate of the one or more of the plurality of switching devices and before comparing the gate-emitter voltage of the one or more plurality of switching devices to a reference voltage range corresponding to the commanded state for the gate of the one or more of the plurality of switching devices. ### Claim 11 (depends on 1) The method of claim 1, wherein implementing the control action based on the actual state of the gate of the one or more of the plurality of switching devices further comprises: shutting down the multi-level bridge power converter of the electrical power system in order to limit damage to a single phase leg of the multi-level bridge power converter. ### Claim 12 (depends on 1) The method of claim 1, further comprising measuring, via at least one voltage sensor, the gate-emitter voltage of the one or more of the plurality of switching devices. ### Claim 13 (depends on 1) The method of claim 1, wherein the plurality of switching devices are insulated gate bipolar transistors (IGBTs). ### Claim 14 (depends on 1) The method of claim 1, wherein the electrical power system is a wind turbine power system. ### Claim 15 A multi-level bridge power converter with a plurality of phase legs, comprising: a first converter and a second converter coupled together via a DC link, each of the first and second converters comprising a plurality of switching devices; and a controller configured to operate the first and second converters, the controller comprising at least one processor, the at least one processor configured to perform a plurality of operations, the plurality of operations comprising: receiving a commanded state for a gate of one or more of the plurality of switching devices; receiving a gate-emitter voltage of the one or more of the plurality of switching devices, the gate-emitter voltage referring to a voltage from the gate to an emitter of the one or more of the plurality of switching devices; comparing, via at least one comparator of the controller, the gate-emitter voltage of the one or more plurality of switching devices to a reference voltage range corresponding to the commanded state for the gate of the one or more of the plurality of switching devices; determining an actual state of the gate of the one or more of the plurality of switching devices based on the comparison; and implementing a control action based on the actual state of the gate of the one or more of the plurality of switching devices. ### Claim 16 (depends on 15) The multi-level bridge power converter of claim 15, wherein the commanded state is one of an ON state or an OFF state, and wherein comparing the gate-emitter voltage of one or more of the plurality of switching devices to the reference voltage range corresponding to the commanded state of the gate of the one or more plurality of switching devices further comprises: comparing the gate-emitter voltage of the one or more plurality of switching devices to each of an ON reference voltage range corresponding to the ON state or an OFF reference voltage range corresponding to the OFF state via, at least, first and second comparators. ### Claim 17 (depends on 16) The multi-level bridge power converter of claim 16, wherein determining the actual state of the gate of the one or more plurality of switching devices based on the comparison further comprises: if the commanded state of the gate of the one or more plurality of switching devices is the ON state, determining whether an output of the first comparator is within the ON reference voltage range and if so, then determining that the actual state of the gate of the one or more of the plurality of switching devices is the ON state. ### Claim 18 (depends on 17) The multi-level bridge power converter of claim 17, wherein determining the actual state of the gate of the one or more plurality of switching devices based on the comparison further comprises: if the commanded state of the gate of the one or more plurality of switching devices is the OFF state, determining whether an output of the second comparator is within the OFF reference voltage range and if so, then determining that the actual state of the gate of the one or more of the plurality of switching devices is the OFF state. ### Claim 19 (depends on 17) The multi-level bridge power converter of claim 17, wherein determining the actual state of the gate of the one or more plurality of switching devices based on the comparison further comprises: if the commanded state of the gate of the one or more plurality of switching devices is one of the ON state or the OFF state, determining whether an output of a third comparator is within a FAULT reference voltage range and if so, then determining that the actual state of the gate of the one or more of the plurality of switching devices is a FAULT state. ### Claim 20 (depends on 15) The multi-level bridge power converter of claim 15, wherein implementing the control action based on the actual state of the gate of the one or more of the plurality of switching devices further comprises: shutting down the multi-level bridge power converter of the electrical power system in order to limit damage to a single phase leg of the multi-level bridge power converter.