# US 10,480,835 B2 · Gas-replenishing and enthalpy-increasing control method, device and apparatus for two-stage compressor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,835 B2 - Document ID: US10480835B2 - Status: Granted - Kind: B2 - Application number: 15/775,476 - Filed: 2016-05-05 - Published: 2018-12-13 - Granted: 2019-11-19 - Earliest claimed: 2015-12-11 - Assignees: Gree Electric Appliances, Inc. of Zhuhai - Applicants: Gree Electric Appliances, Inc. of Zhuhai - Inventors: Huan Zhao; Jun Shen; Feng Tan; Youxuan Liang; Pengfei Li - Web page: https://patentgrep.com/patent/US10480835B2 ## 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 41/34: with the valve member being actuated by electric means, e.g. by piezoelectric actuators - F25B 41/385: Dispositions with two or more expansion means arranged in parallel on a refrigerant line leading to the same evaporator - F25B 2400/074: with multiple cylinders - F25B 2400/13: Economisers - F25B 2400/23: Separators - F25B 2500/19: Calculation of parameters - F25B 2500/28: Means for preventing liquid refrigerant entering into the compressor - F25B 2600/01: Timing - F25B 2600/2509: Economiser valves - F25B 2600/2513: Expansion valves - F25B 2700/1933: Suction pressures - F25B 2700/21151: at the suction side of the compressor - 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 Provided are a gas-replenishing and enthalpy-increasing control method, device and apparatus for a two-stage compressor. The method includes: when a gas-replenishing electronic expansion valve needs to be opened, gradually increasing, by a controller, an opening degree of the gas-replenishing electronic expansion valve in a time sequence; after the gas-replenishing electronic expansion valve is opened, acquiring a detected gas-replenishing superheat degree of a two-stage compressor; and adjusting, based on the gas-replenishing superheat degree of the two-stage compressor, the opening degree of the gas-replenishing electronic expansion valve, wherein the gas-replenishing electronic expansion valve is disposed between a medium-pressure liquid storage tank and the two-stage compressor, and when the opening degree of the gas-replenishing electronic expansion valve is not zero, a gaseous refrigerant in the medium-pressure liquid storage tank replenishes gas and increases enthalpy for the two-stage compressor. ## Claims ### Claim 1 A gas-replenishing and enthalpy-increasing control method for a two-stage compressor, comprising: when a gas-replenishing electronic expansion valve needs to be opened, gradually increasing, by a controller, an opening degree of the gas-replenishing electronic expansion valve in a time sequence; after the gas-replenishing electronic expansion valve is opened, acquiring a detected gas-replenishing superheat degree of a two-stage compressor; and adjusting, based on the gas-replenishing superheat degree of the two-stage compressor, the opening degree of the gas-replenishing electronic expansion valve, wherein the gas-replenishing electronic expansion valve is disposed between a medium-pressure liquid storage tank and the two-stage compressor, and when the opening degree of the gas-replenishing electronic expansion valve is not zero, a gaseous refrigerant in the medium-pressure liquid storage tank replenishes gas and increases enthalpy for the two-stage compressor; wherein acquiring the detected gas-replenishing superheat degree of the two-stage compressor comprises: collecting a gas-replenishing temperature and a gas-replenishing pressure of the two-stage compressor; acquiring a saturation temperature corresponding to the gas-replenishing pressure; and taking a difference between the gas-replenishing temperature and the saturation temperature as the gas-replenishing superheat degree of the two-stage compressor; wherein adjusting, based on the gas-replenishing superheat degree of the two-stage compressor, the opening degree of the gas-replenishing electronic expansion valve comprises: judging whether the gas-replenishing superheat degree of the two-stage compressor is greater than a preset superheat degree at predetermined intervals; when the gas-replenishing superheat degree of the two-stage compressor is greater than the preset superheat degree, determining that the replenished gas of the two-stage compressor entrains liquid; when the gas-replenishing superheat degree of the two-stage compressor is not greater than the preset superheat degree, determining that the replenished gas of the two-stage compressor does not entrain liquid; and adjusting the opening degree of the gas-replenishing electronic expansion valve according to the situation that the replenished gas of the two-stage compressor entrains liquid; wherein adjusting the opening degree of the gas-replenishing electronic expansion valve according to the situation that the replenished gas of the two-stage compressor entrains liquid comprises: when the replenished gas of the two-stage compressor entrains liquid, reducing the current opening degree of the gas-replenishing electronic expansion valve to a preset opening degree, wherein the preset opening degree is an opening degree preset based on a full opening degree of the gas-replenishing electronic expansion valve, and the full opening degree is an opening degree when the gas-replenishing electronic expansion valve is fully opened; and when the replenished gas of the two-stage compressor does not entrain liquid, keeping the current opening degree of the gas-replenishing electronic expansion valve unchanged or increasing the current opening degree. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein gradually increasing, by the controller, the opening degree of the gas-replenishing electronic expansion valve in the time sequence when the gas-replenishing electronic expansion valve needs to be opened comprises: after the two-stage compressor is opened and operates for a first preset time period, controlling, by the controller, the opening degree of the gas-replenishing electronic expansion valve to be a first preset opening degree; when the opening degree of the gas-replenishing electronic expansion valve is the first preset opening degree, after the gas-replenishing expansion valve operates for a second preset time period, increasing the opening degree of the gas-replenishing electronic expansion valve to a second preset opening degree; and when the opening degree of the gas-replenishing electronic expansion valve is a second preset opening degree, after the gas-replenishing expansion valve operates for a third preset time period, fully opening the gas-replenishing electronic expansion valve. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein keeping the current opening degree of the gas-replenishing electronic expansion valve unchanged or increasing the current opening degree comprises: when determining that the replenished gas of the two-stage compressor does not entrain liquid, if the operations of reducing the current opening degree of the gas-replenishing electronic expansion valve and keeping the current opening degree of the gas-replenishing electronic expansion valve are executed respectively after whether the gas-replenishing superheat degree is greater than the preset opening degrees has been judged previously twice, executing the operation of increasing the current opening degree of the gas-replenishing electronic expansion valve, and otherwise, executing the operation of keeping the current opening degree of the gas-replenishing electronic expansion valve. ### Claim 4 A gas-replenishing and enthalpy-increasing control device for a two-stage compressor, comprising: a gas-replenishing electronic expansion valve, disposed between a medium-pressure liquid storage tank and a two-stage compressor; and a controller, connected to the gas-replenishing electronic expansion valve, and configured to gradually increase an opening degree of the gas-replenishing electronic expansion valve in a time sequence when the gas-replenishing electronic expansion valve needs to be opened, acquire a gas-replenishing superheat degree of the two-stage compressor after the gas-replenishing electronic expansion valve is opened, and adjust the opening degree of the gas-replenishing electronic expansion valve based on the gas-replenishing superheat degree of the two-stage compressor; a detection apparatus, connected to the controller, and configured to collect a gas-replenishing temperature and a gas-replenishing pressure of the two-stage compressor, wherein the controller comprises: a reading apparatus, connected to the detection apparatus, and configured to read a saturation temperature corresponding to the gas-replenishing pressure; and a calculator, connected to the detection apparatus and the reading apparatus, and configured to calculate a difference between the gas-replenishing temperature and the saturation temperature, so as to obtain the gas-replenishing superheat degree; wherein the controller is further configured to: when the gas-replenishing superheat degree of the two-stage compressor is greater than the preset superheat degree, determine that the replenished gas of the two-stage compressor entrains liquid, and reduce the current opening degree of the gas-replenishing electronic expansion valve to a preset opening degree, wherein the preset opening degree is an opening degree preset based on a full opening degree of the gas-replenishing electronic expansion valve, and the full opening degree is an opening degree when the gas-replenishing electronic expansion valve is fully opened when the gas-replenishing superheat degree of the two-stage compressor is not greater than the preset superheat degree, determine that the replenished gas of the two-stage compressor does not entrain liquid, and keep the current opening degree of the gas-replenishing electronic expansion valve unchanged or increasing the current opening degree. ### Claim 5 (depends on 4) The device as claimed in claim 4, wherein the detection apparatus further comprises: a pressure sensor, disposed at a gas-replenishing port of the two-stage compressor, and configured to collect the gas-replenishing pressure; and a temperature-sensing package, disposed at the gas-replenishing port of the two-stage compressor, and configured to collect the gas-replenishing temperature. ### Claim 6 (depends on 4) The device as claimed in claim 4, further comprising: a four-way valve, a first end being connected to the two-stage compressor; a gas-liquid separator, a first end being connected to a second end of the four-way valve, and a second end being connected to the two-stage compressor; an outdoor heat exchanger, a first end being connected to a third end of the four-way valve; and an indoor heat exchanger, a first end being connected to a fourth end of the four-way valve, and a second end being connected to the medium-pressure liquid storage tank. ### Claim 7 (depends on 6) The device as claimed in claim 6, further comprising: an indoor electronic expansion valve, disposed between the indoor heat exchanger and the medium-pressure liquid storage tank; and an outdoor electronic expansion valve, disposed between the outdoor heat exchanger and the medium-pressure liquid storage tank. ### Claim 8 A gas-replenishing and enthalpy-increasing control apparatus for a two-stage compressor, comprising: a control unit, configured to allow, when a gas-replenishing electronic expansion valve needs to be opened, a controller to gradually increase an opening degree of the gas-replenishing electronic expansion valve in a time sequence; an acquisition unit, configured to acquire, after the gas-replenishing electronic expansion valve is opened, a detected gas-replenishing superheat degree of a two-stage compressor; and an adjustment unit, configured to adjust, based on the gas-replenishing superheat degree of the two-stage compressor, the opening degree of the gas-replenishing electronic expansion valve, wherein the gas-replenishing electronic expansion valve is disposed between a medium-pressure liquid storage tank and the two-stage compressor, and when the opening degree of the gas-replenishing electronic expansion valve is not zero, a gaseous refrigerant in the medium-pressure liquid storage tank replenishes gas and increases enthalpy for the two-stage compressor; wherein the acquisition unit comprises: a collection module, configured to collect a gas-replenishing temperature and a gas-replenishing pressure of the two-stage compressor; an acquisition module, configured to acquire a saturation temperature corresponding to the gas-replenishing pressure; and a calculation module, configured to take a difference between the gas-replenishing temperature and the saturation temperature as the gas-replenishing superheat degree of the two-stage compressor; wherein the adjustment unit comprises: a judgment module, configured to judge whether the gas-replenishing superheat degree of the two-stage compressor is greater than a preset superheat degree at predetermined intervals; a first determination module, configured to determine that, if the gas-replenishing superheat degree of the two-stage compressor is greater than the preset superheat degree, the replenished gas of the two-stage compressor entrains liquid; a second determination module, configured to determine that, if the gas-replenishing superheat degree of the two-stage compressor is not greater than the preset superheat degree, the replenished gas of the two-stage compressor does not entrain liquid; and an adjustment module, configured to adjust the opening degree of the gas-replenishing electronic expansion valve according to the situation that the replenished gas of the two-stage compressor entrains liquid; wherein the adjustment unit is further configured to: when the replenished gas of the two-stage compressor entrains liquid, reduce the current opening degree of the gas-replenishing electronic expansion valve to a preset opening degree, wherein the preset opening degree is an opening degree preset based on a full opening degree of the gas-replenishing electronic expansion valve, and the full opening degree is an opening degree when the gas-replenishing electronic expansion valve is fully opened; and when the replenished gas of the two-stage compressor does not entrain liquid, keep the current opening degree of the gas-replenishing electronic expansion valve unchanged or increasing the current opening degree. ### Claim 9 (depends on 8) The apparatus as claimed in claim 8, wherein the control unit comprises: a first control module, configured to control, after the two-stage compressor is opened and operates for a first preset time period, the opening degree of the gas-replenishing electronic expansion valve to be a first preset opening degree; a second control module, configured to increase, when the opening degree of the gas-replenishing electronic expansion valve is the first preset opening degree and the gas-replenishing expansion valve have operated for a second preset time period, the opening degree of the gas-replenishing electronic expansion valve to a second preset opening degree; and a third control module, configured to fully open, when the opening degree of the gas-replenishing electronic expansion valve is a second preset opening degree and the gas-replenishing expansion valve have operated for a third preset time period, the gas-replenishing electronic expansion valve.