# US 10,480,838 B2 · Control device for refrigeration cycle apparatus, and control method for refrigeration cycle apparatus, and refrigeration cycle apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,838 B2 - Document ID: US10480838B2 - Status: Granted - Kind: B2 - Application number: 15/545,484 - Filed: 2015-03-02 - Published: 2018-01-11 - Granted: 2019-11-19 - Earliest claimed: 2015-03-02 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Masashi Fujitsuka; Masaya Kimura; Kazunori Tsuchino - Web page: https://patentgrep.com/patent/US10480838B2 ## CPC - F25B 49/02: for compression type machines, plants or systems - F25B 13/00: Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) - F25B 41/35: by rotary motors, e.g. by stepping motors - F25B 2313/0314: Temperature sensors near the indoor heat exchanger - F25B 2313/0315: Temperature sensors near the outdoor heat exchanger - F25B 2500/19: Calculation of parameters - F25B 2600/0253: with variable speed - F25B 2600/2513: Expansion valves - F25B 2700/1931: Discharge pressures - F25B 2700/1933: Suction pressures - F25B 2700/2104: of an indoor room or compartment - F25B 2700/21152: at the discharge side of the compressor - Y02B 30/70: Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A refrigeration cycle apparatus controller includes an expansion-valve controller configured to output an opening-degree command for an expansion valve based on a deviation between a discharge temperature of refrigerant discharged from a compressor and a set discharge temperature, and at least two control parameters including a proportionality coefficient and an integral coefficient, a flow-rate-correction-coefficient calculator configured to calculate a flow-rate correction coefficient from a refrigerant flow rate of refrigerant circulating through a refrigerant circuit and a preset flow-rate reference value, and a coefficient corrector configured to calculate the proportionality coefficient by correcting a preset proportionality-coefficient reference value based on the flow-rate correction coefficient, and calculate the integral coefficient by correcting a preset integral-coefficient reference value based on the flow-rate correction coefficient. The proportionality coefficient and the integral coefficient are calculated such that a variation range of the integral coefficient rate is larger than a variation range of the proportionality coefficient. ## Claims ### Claim 1 A refrigeration cycle apparatus comprising: a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected by a refrigerant pipe, and a controller configured to control an opening-degree of the expansion valve, wherein the controller is configured to detect a discharge temperature of refrigerant discharged from the compressor with a sensor, output an opening-degree command for the expansion valve on a basis of a discharge-temperature deviation between the discharge temperature and a set discharge temperature, and at least two types of control parameters including a proportionality coefficient and an integral coefficient such that the discharge temperature becomes the set discharge temperature, and calculate the proportionality coefficient and the integral coefficient corresponding to a refrigerant flow rate of refrigerant circulating through the refrigerant circuit by correcting preset reference values such that a variation range of the integral coefficient within a variation range of the refrigerant flow rate is larger than a variation range of the proportionality coefficient within the variation range of the refrigerant flow rate. ### Claim 2 (depends on 1) The refrigeration cycle apparatus of claim 1, wherein the controller is configured to output a rotation-frequency command for controlling a rotation frequency of the compressor such that a room temperature measured by a sensor becomes a set room temperature. ### Claim 3 (depends on 2) The refrigeration cycle apparatus of claim 2, wherein the controller is configured to compute the set discharge temperature on a basis of the output rotation-frequency command and discharge pressure and suction pressure of the compressor, wherein the discharge pressure and the suction pressure being measured by sensors or being calculated from temperatures measured by sensors. ### Claim 4 (depends on 2) The refrigeration cycle apparatus of claim 2, wherein the controller is configured to calculate a feed forward amount by using the rotation-frequency command and a feed-forward proportionality coefficient, and add the feed forward amount to the opening-degree command for the expansion valve, and then output the opening-degree command for the expansion valve. ### Claim 5 (depends on 1) The refrigeration cycle apparatus of claim 1, wherein the controller is configured to correct the opening-degree command for the expansion valve such that the opening-degree command for the expansion valve and a refrigerant-flow-rate characteristic specific to the expansion valve have a linear relationship. ### Claim 6 (depends on 1) The refrigeration cycle apparatus of claim 1, wherein the controller is configured to calculate a flow-rate correction coefficient from the refrigerant flow rate of refrigerant circulating through the refrigerant circuit and a preset flow-rate reference value, and calculate the proportionality coefficient by correcting a preset proportionality-coefficient reference value on a basis of the flow-rate correction coefficient, and calculate the integral coefficient by correcting a preset integral-coefficient reference value on a basis of the flow-rate correction coefficient. ### Claim 7 (depends on 6) The refrigeration cycle apparatus of claim 6, wherein the controller is configured to control a rotation frequency of the compressor such that a room temperature measured by a sensor becomes a set room temperature. ### Claim 8 (depends on 7) The refrigeration cycle apparatus of claim 7, wherein the controller is configured to calculate the flow-rate correction coefficient from the refrigerant flow rate and the flow-rate reference value, with any of the opening-degree command for the expansion valve, an actual opening degree of the expansion valve, the rotation-frequency command for the compressor, and an actual rotation frequency of the compressor being as the refrigerant flow rate. ### Claim 9 (depends on 8) The refrigeration cycle apparatus of claim 8, wherein the controller is configured to calculate a pressure correction coefficient by using discharge pressure, suction pressure of the compressor and a preset pressure-difference reference value, wherein the discharge pressure and the suction pressure being measured by sensors or being calculated from temperatures measured by sensors, and calculate the flow-rate correction coefficient by taking account of the pressure correction coefficient. ### Claim 10 (depends on 7) The refrigeration cycle apparatus of claim 7, wherein the controller is configured to calculate a feed forward amount by using the rotation-frequency command for the compressor and a feed-forward proportionality coefficient, and add the feed forward amount to the opening-degree command for the expansion valve, and then output the opening-degree command for the expansion valve. ### Claim 11 (depends on 10) The refrigeration cycle apparatus of claim 10, wherein the controller is configured to calculate the feed-forward proportionality coefficient by correcting a preset feed-forward proportionality reference value on a basis of the flow-rate correction coefficient, and compute the feed forward amount from the feed-forward proportionality coefficient and the rotation-frequency command for the compressor. ### Claim 12 A controller for a refrigeration cycle apparatus that includes a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected by a refrigerant pipe, the controller is configured to: detect a discharge temperature of refrigerant discharged from the compressor from a sensor, output an opening-degree command for the expansion valve on a basis of a discharge-temperature deviation between the discharge temperature and a set discharge temperature, and at least two types of control parameters including a proportionality coefficient and an integral coefficient such that the discharge temperature becomes the set discharge temperature, and calculate the proportionality coefficient and the integral coefficient corresponding to a refrigerant flow rate of refrigerant circulating through the refrigerant circuit, the proportionality coefficient and the integral coefficient is calculated by correcting preset reference values such that a variation range of the integral coefficient within a variation range of the refrigerant flow rate is larger than a variation range of the proportionality coefficient within the variation range of the refrigerant flow rate.