# US 2021/0344294 A1 · Rotary-machine control device, refrigerant compression apparatus, and air conditioner > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344294 A1 - Document ID: US20210344294A1 - Status: Published application - Kind: A1 - Application number: 17/279,589 - Filed: 2019-01-23 - Published: 2021-11-04 - Earliest claimed: 2019-01-23 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Akane HONGYO; Akira SATAKE; Kenji TAKAHASHI - Web page: https://patentgrep.com/patent/US20210344294A1 ## CPC - H02P 25/18: with arrangements for switching the windings, e.g. with mechanical switches or relays - H02P 29/0243: {the fault being a broken phase} - F25B 31/026: {with compressor of rotary type} - H02P 27/06: using DC to AC converters or inverters (H02P27/05 takes precedence) - H02P 29/024: Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load - H02P 29/025: {the fault being a power interruption} - F25B 49/022: {Compressor control arrangements} - F25B 2700/151: of the compressor motor - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract A rotary-machine control device includes: a connection switching device switching a connection state of stator windings of a rotary machine; a current detection unit detecting a rotary machine current flowing in the rotary machine; a voltage application unit applying voltage to the rotary machine; a control unit generating a voltage command provided to the voltage application unit and outputting a switching command to switch the connection state to the connection switching device; and an open-phase determination unit determining presence or absence of disconnection in the rotary machine or presence or absence of disconnection of a power distribution line to the rotary machine. During rotation of the rotary machine, the control unit outputs the switching command and the open-phase determination unit determines presence or absence of disconnection. ## Claims ### Claim 1 A rotary-machine control device comprising: a connection switching device to switch a connection state of stator windings of a rotary machine; a current detector to detect a rotary machine current flowing in the rotary machine; voltage application circuitry to apply voltage to the rotary machine; control circuitry to generate a voltage command provided to the voltage application circuitry and output a switching command to switch the connection state to the connection switching device; and open-phase determination circuitry to determine presence or absence of disconnection in the rotary machine or presence or absence of disconnection of a power distribution line to the rotary machine, wherein during rotation of the rotary machine, the control circuitry outputs the switching command and the open-phase determination circuitry determines presence or absence of disconnection, and after a predetermined period of time elapses from output of the switching command, the open-phase determination circuitry starts to determine presence or absence of disconnection. ### Claim 2 (canceled) ### Claim 3 (depends on 1) The rotary-machine control device according to claim 1, wherein the predetermined period of time is greater than or equal to a mechanical time constant of the connection switching device. ### Claim 4 (depends on 1) The rotary-machine control device according to claim 1, wherein when a test voltage for the determination is applied to the rotary machine from the voltage application circuitry, the open-phase determination circuitry determines presence or absence of disconnection by comparing a value of the rotary machine current detected by the current detector with a reference value. ### Claim 5 (depends on 1) A refrigerant compression apparatus comprising: a compressor including a rotary machine, the compressor compressing a medium through rotation of the rotary machine; and the rotary-machine control device according to claim 1 to output a three-phase alternating-current voltage to the rotary machine. ### Claim 6 (depends on 5) An air conditioner comprising the refrigerant compression apparatus according to claim 5. ### Claim 7 (depends on 3) The rotary-machine control device according to claim 3, wherein when a test voltage for the determination is applied to the rotary machine from the voltage application circuitry, the open-phase determination circuitry determines presence or absence of disconnection by comparing a value of the rotary machine current detected by the current detector with a reference value. ### Claim 8 A rotary-machine control device comprising: a connection switching device to switch a connection state of stator windings of a rotary machine; a current detector to detect a rotary machine current flowing in the rotary machine; voltage application circuitry to apply voltage to the rotary machine; control circuitry to generate a voltage command provided to the voltage application circuitry and output a switching command to switch the connection state to the connection switching device; and open-phase determination circuitry to determine presence or absence of disconnection in the rotary machine or presence or absence of disconnection of a power distribution line to the rotary machine, wherein during rotation of the rotary machine, the control circuitry outputs the switching command and the open-phase determination circuitry determines presence or absence of disconnection, and when a test voltage for the determination is applied to the rotary machine from the voltage application circuitry, the open-phase determination circuitry determines presence or absence of disconnection by comparing a value of the rotary machine current detected by the current detector with a reference value. ### Claim 9 (depends on 3) A refrigerant compression apparatus comprising: a compressor including a rotary machine, the compressor compressing a medium through rotation of the rotary machine; and the rotary-machine control device according to claim 3 to output a three-phase alternating-current voltage to the rotary machine. ### Claim 10 (depends on 4) A refrigerant compression apparatus comprising: a compressor including a rotary machine, the compressor compressing a medium through rotation of the rotary machine; and the rotary-machine control device according to claim 4 to output a three-phase alternating-current voltage to the rotary machine. ### Claim 11 (depends on 7) A refrigerant compression apparatus comprising: a compressor including a rotary machine, the compressor compressing a medium through rotation of the rotary machine; and the rotary-machine control device according to claim 7 to output a three-phase alternating-current voltage to the rotary machine. ### Claim 12 (depends on 9) An air conditioner comprising the refrigerant compression apparatus according to claim 9. ### Claim 13 (depends on 10) An air conditioner comprising the refrigerant compression apparatus according to claim 10. ### Claim 14 (depends on 11) An air conditioner comprising the refrigerant compression apparatus according to claim 11.