# US 11,442,092 B2 · Power conversion device and method for detecting magnetic saturation of common-mode reactor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,442,092 B2 - Document ID: US11442092B2 - Status: Granted - Kind: B2 - Application number: 17/623,251 - Filed: 2019-09-02 - Published: 2022-06-30 - Granted: 2022-09-13 - Earliest claimed: 2019-09-02 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Masafumi Ichihara - Web page: https://patentgrep.com/patent/US11442092B2 ## CPC - G01R 27/2611: {Measuring inductance} - H02M 7/53871: {with automatic control of output voltage or current} - H02M 1/0064: {Magnetic structures combining different functions, e.g. storage, filtering or transformation} - H02M 1/123: {Suppression of common mode voltage or current} - H02P 27/06: using DC to AC converters or inverters (H02P27/05 takes precedence) - 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) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract A power conversion device includes a semiconductor power converter that converts direct current power into alternating current power for a motor, a common-mode reactor having first and second auxiliary windings added thereto, the common-mode reactor reducing common-mode current that may flow between the semiconductor power converter and the motor, a signal generator that superimposes an alternating current on the first auxiliary winding, and a detection circuit that detects a saturation state of the common-mode reactor on the basis of the superimposed current superimposed on the first auxiliary winding and a winding voltage generated in the second auxiliary winding by the superimposed current. ## Claims ### Claim 1 A power conversion device comprising: a power converter to convert direct current power into alternating current power for a load; a common-mode reactor having first and second auxiliary windings added thereto, the common-mode reactor reducing a common-mode current that flows between the power converter and the load; a signal generator to superimpose an alternating current on the first auxiliary winding; and a detection circuit to detect a saturation state of the common-mode reactor on a basis of a superimposed current superimposed on the first auxiliary winding and a winding voltage generated in the second auxiliary winding by the superimposed current. ### Claim 2 (depends on 1) The power conversion device according to claim 1, wherein a frequency of the superimposed current is higher than a frequency of the common-mode current. ### Claim 3 (depends on 1) The power conversion device according to claim 1, wherein the detection circuit detects a saturation state of the common-mode reactor during flow of the common-mode current through the common-mode reactor. ### Claim 4 (depends on 1) The power conversion device according to claim 1, wherein the detection circuit includes a first rectifier to rectify the winding voltage, a second rectifier to rectify a superimposed current signal output from the signal generator, a level adjuster to adjust at least an output level of a first rectification value among the first rectification value output from the first rectification unit and a second rectification value output from the second rectification unit, and a comparator to compare the first rectification value output from the level adjustment unit with the second rectification value. ### Claim 5 (depends on 1) The power conversion device according to claim 1, comprising a calculator for quantitatively determining a saturation state of the common-mode reactor, wherein the calculator calculates a mutual inductance between the first auxiliary winding and the second auxiliary winding. ### Claim 6 (depends on 1) The power conversion device according to claim 1, comprising a calculator for quantitatively determining a saturation state of the common-mode reactor, wherein the calculator calculates a saturation time ratio that is a ratio of time when the common-mode reactor is in a saturation state to an entire time when the superimposed current flows through the common-mode reactor. ### Claim 7 (depends on 1) The power conversion device according to claim 1, comprising a calculator for quantitatively determining a saturation state of the common-mode reactor, wherein the calculator calculates a current range of the common-mode reactor in a non-saturation state on the basis of an amplitude value of the superimposed current of when the common-mode reactor changes from a non-saturation state to a saturation state or from a saturation state to a non-saturation state as the amplitude value of the superimposed current is changed. ### Claim 8 A magnetic saturation detection method for detecting magnetic saturation of a common-mode reactor, the common-mode reactor being disposed between a power converter and a load and having first and second auxiliary windings added thereto, the method being applied to a device, the device including the common-mode reactor and a signal generator to generate a current to be superimposed on the first auxiliary winding, the method comprising: superimposing an alternating current on the first auxiliary winding; detecting a winding voltage generated in the second auxiliary winding by a superimposed current superimposed on the first auxiliary winding; and detecting magnetic saturation of the common-mode reactor on a basis of the superimposed current and the winding voltage. ### Claim 9 (depends on 8) The magnetic saturation detection method for a common-mode reactor according to claim 8, wherein detecting the magnetic saturation of the common-mode reactor includes processing of calculating a mutual inductance between the first auxiliary winding and the second auxiliary winding. ### Claim 10 (depends on 8) The magnetic saturation detection method for a common-mode reactor according to claim 8, wherein detecting the magnetic saturation of the common-mode reactor includes processing of calculating a saturation time ratio that is a ratio of time when the common-mode reactor is in a saturation state to an entire time when the superimposed current flows through the common-mode reactor. ### Claim 11 (depends on 8) The magnetic saturation detection method for a common-mode reactor according to claim 8, wherein detecting the magnetic saturation of the common-mode reactor includes processing of calculating a current range of the common-mode reactor in a non-saturation state on the basis of an amplitude value of the superimposed current of when the common-mode reactor changes from a non-saturation state to a saturation state or from a saturation state to a non-saturation state as the amplitude value of the superimposed current is changed.