# US 12,184,162 B1 · Powering an impedance injection unit during startup operations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,184,162 B1 - Document ID: US12184162B1 - Status: Granted - Kind: B1 - Application number: 17/249,278 - Filed: 2021-02-25 - Granted: 2024-12-31 - Earliest claimed: 2020-05-29 - Assignees: Smart Wires Inc. - Applicants: Smart Wires Inc. - Inventors: Shreesha Adiga Manoor; Vinod Babu; Govind Chavan; Haroon Inam; Amrit Iyer; Arthur Kelley; Volodymyr Strelchuk - Web page: https://patentgrep.com/patent/US12184162B1 ## CPC - H02M 1/32: Means for protecting converters other than automatic disconnection - G05F 1/12: wherein the variable actually regulated by the final control device is AC (G05F1/625 takes precedence) - H02J 3/18: Arrangements for adjusting, eliminating or compensating reactive power in networks - H02M 1/0006: {Arrangements for supplying an adequate voltage to the control circuit of converters} - H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters - H02M 1/36: Means for starting or stopping converters - H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} - 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) - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A multi-mode power supply is described for providing power to an impedance injection unit that is operable to inject reactive power into a power transmission line. The impedance injection unit is configured to operate safely in the presence of switching states of the impedance injection unit, and in the presence of disturbances such as surge currents in the power transmission line, by the multi-mode power supply clamping a potential overvoltage to a safe level. The power supply contains analog and digital circuits and can recover automatically from a surge current in the transmission line, or from a condition of zero line current. Power harvesting may be achieved via a line connected current transformer, via an internal current transformer, via a DC link capacitor, or from combinations of these. ## Claims ### Claim 1 An impedance injection unit for injecting reactive power into a phase of a power transmission line, the impedance injection unit comprising: a controller configured to control injection of the reactive power into the phase of the power transmission line; and a power supply configured to withstand a surge current, an in-rush current, or an over-voltage arising from a disturbance on the phase of the power transmission line, or mode switching of the impedance injection unit, the power supply comprising: a charge harvester configured to harvest charges from the phase of the power transmission line; and circuitry configured to clamp a voltage of the harvested charges to a specific value to withstand the in-rush current or the over-voltage to generate a supply voltage to the controller; wherein: the impedance injection unit is configured to start from a powered down state; the controller is configured to execute a boot up routine when the controller receives the supply voltage from the power supply; and when the controller completes the boot-up routine, the controller is configured to disable the circuitry that clamps the voltage of the harvested charges. ### Claim 2 (depends on 1) The impedance injection unit of claim 1, wherein the circuitry of the power supply is further configured to generate the supply voltage to power up the controller based on the clamped voltage following the disturbance on the phase of the power transmission line. ### Claim 3 (depends on 1) The impedance injection unit of claim 1, wherein the circuitry of the power supply is further configured to generate the supply voltage to power up the controller based on the clamped voltage from a condition of zero current on the phase of the power transmission line. ### Claim 4 (depends on 1) The impedance injection unit of claim 1, wherein the circuitry comprises analog and digital circuitry configured to recover from the surge current or the over-voltage or to start from a condition of zero current on the phase of the power transmission line to generate the supply voltage to the controller. ### Claim 5 (depends on 1) The impedance injection unit of claim 1, wherein the power supply is further configured to receive power from an external line-connected current transformer. ### Claim 6 (depends on 1) The impedance injection unit of claim 1, wherein the power supply is further configured to receive power from an internal current transformer. ### Claim 7 (depends on 1) The impedance injection unit of claim 1, wherein the charge harvester comprises a direct current (DC) link capacitor configured to store the harvested charges from the phase of the power transmission line. ### Claim 8 (depends on 7) The impedance injection unit of claim 7, wherein the circuitry comprises a power switching assembly configured to charge the DC link capacitor. ### Claim 9 (depends on 8) The impedance injection unit of claim 8, wherein the power switching assembly comprises a bank of insulated-gate bipolar transistors (IGBTs). ### Claim 10 (depends on 9) The impedance injection unit of claim 9, wherein the bank of IGBTs are configured to clamp the voltage of the harvested charges to the specific value to withstand the in-rush current or the over-voltage to generate a supply voltage to the controller. ### Claim 11 (depends on 1) The impedance injection unit of claim 1, wherein the circuitry is further configured to receive the harvested charges to generate the supply voltage to maintain operation of the controller even when the phase of the transmission line drops to zero current. ### Claim 12 (depends on 1) The impedance injection unit of claim 1, wherein the charge harvester is configured to continue to harvest charges from the phase of the power transmission line for the power supply to maintain the supply voltage to operate the controller when the controller is configured not to control the injection of reactive power into the phase of the power transmission line. ### Claim 13 A method for safely operating an impedance injection unit applied to a phase of a power transmission line, the method comprising: providing a multi-mode power supply coupled to the phase of the power transmission line; harvesting charges from the phase of the power transmission line to charge a direct current (DC) link capacitor through a power switching assembly that comprises a bank of insulated-gate bipolar transistors (IGBTs) of the multi-mode power supply; and clamping by the bank of IGBTs a voltage of the DC link capacitor to a specific value to withstand in-rush current associated with mode switching of the impedance injection unit when on a phase of the power transmission line, and to generate a supply voltage for the impedance injection unit from the multi-mode power supply. ### Claim 14 (depends on 13) The method of claim 13, further comprising: harvesting power from an external line-connected current transformer by the multi-mode power supply to generate the supply voltage for the impedance injection unit. ### Claim 15 (depends on 13) The method of claim 13, further comprising: harvesting power from an internal current transformer by the multi-mode power supply to generate the supply voltage for the impedance injection unit. ### Claim 16 (depends on 13) The method of claim 13, further comprising: harvesting by the DC link capacitor the charges from the phase of the power transmission line starting from a powered down state of the impedance injection unit. ### Claim 17 (depends on 13) The method of claim 13, further comprising: continuing harvesting charges from the phase of the power transmission line for the multi-mode power supply to maintain the supply voltage to the impedance injection unit even when the impedance injection unit is not injecting reactive power into the phase of the power transmission line.