CN-116412464-B - Multi-split air conditioner

CN116412464BCN 116412464 BCN116412464 BCN 116412464BCN-116412464-B

Abstract

The invention discloses a multi-split air conditioner which comprises an outdoor unit and a plurality of indoor units, wherein the indoor units comprise an indoor heat exchanger and an indoor machine electronic expansion valve, the indoor heat exchanger is connected with the outdoor unit through the indoor machine electronic expansion valve, the indoor heat exchanger comprises an inlet and a plurality of elbows, the indoor unit further comprises an indoor machine controller, an inlet temperature sensor, an elbow temperature sensor and an indoor temperature sensor which are connected with the indoor machine controller, the inlet temperature sensor and the elbow temperature sensor are respectively arranged at one of the inlet and the elbow and used for detecting the inlet temperature, the elbow temperature and the indoor temperature sensor and transmitting the detected indoor temperature to the indoor machine controller, the indoor machine controller is configured to judge whether the indoor machine electronic expansion valve is in a limit small opening state according to the inlet temperature, the elbow temperature and the indoor temperature, if so, the indoor machine electronic expansion valve is controlled to increase the opening state, and if not, the indoor machine controller is controlled to keep executing overheat degree control. The invention detects and controls the opening state of the internal motor electronic expansion valve, and prevents the internal refrigeration from being ineffective.

Inventors

SUN KAI
ZHANG YI

Assignees

青岛海信日立空调系统有限公司

Dates

Publication Date: 20260508
Application Date: 20230418

Claims (9)

1. The multi-split air conditioner is characterized by comprising an outdoor unit and a plurality of indoor units, wherein each indoor unit comprises an indoor heat exchanger and an internal machine electronic expansion valve, and the indoor heat exchanger is connected with the outdoor unit through the internal machine electronic expansion valve and comprises an inlet, an outlet and a plurality of elbows; The indoor unit further comprises an indoor unit controller, an inlet temperature sensor, an elbow temperature sensor and an indoor temperature sensor which are respectively connected with the indoor unit controller; the inlet temperature sensor and the elbow temperature sensor are respectively arranged at the inlet and one of the elbows and used for detecting inlet temperature and elbow temperature and transmitting the inlet temperature and the elbow temperature to the inner machine controller; The multi-split air conditioner further comprises an air suction superheat degree acquisition device and a pressure sensor, wherein the air suction superheat degree acquisition device and the pressure sensor are respectively arranged on the outdoor unit and are respectively connected with the inner unit controller, the air suction superheat degree acquisition device is used for acquiring the air suction superheat degree of the outdoor unit and transmitting the air suction superheat degree to the inner unit controller, and the pressure sensor is used for acquiring low pressure and transmitting the low pressure to the inner unit controller; The internal machine controller is configured to judge whether the internal machine electronic expansion valve is in a limit small opening state according to the inlet temperature, the elbow temperature, the indoor temperature, the outdoor machine suction superheat degree and the low pressure, and comprises a first temperature limit value, a second temperature limit value, a first opening limit value, a first low pressure limit value and a first time length, and is configured to judge whether the opening degree of the internal machine electronic expansion valve is lower than the first opening limit value, whether the low pressure is lower than the first low pressure limit value and whether the difference between the inlet temperature and the suction superheat degree exceeds the first temperature limit value for the first time length or the difference between the elbow temperature and the suction superheat degree exceeds the first temperature limit value for the first time length or the difference between the indoor temperature and the second temperature limit value does not exceed the inlet temperature for the first time length or the difference between the indoor temperature and the second temperature limit value does not exceed the first elbow temperature for the first time length; When judging that the conditions are all yes, determining that the internal electronic expansion valve is in the limit small opening state, otherwise, not in the limit small opening state; And when the internal electronic expansion valve is not in the limit small opening state, the superheat degree control is kept to be executed.
2. The multi-split air conditioner according to claim 1, wherein the internal machine controller is further configured with an operation time limit value and is configured to accumulate a refrigeration cycle temperature control mode duration, determine whether the refrigeration cycle temperature control mode duration reaches the operation time limit value or more, and if so, determine whether the internal machine electronic expansion valve is in the limit small opening state.
3. The multi-split air conditioner according to claim 2, wherein the indoor unit controller is configured to end the increased opening degree control if the indoor unit ends a refrigeration cycle when executing the increased opening degree control; And when the indoor unit finishes the refrigeration cycle or is switched to other operation modes, the duration of the refrigeration cycle temperature control mode is cleared.
4. The multi-split air conditioner according to any one of claims 1 to 3, wherein the indoor unit controller is configured with an increased opening degree, a minimum opening degree, a second opening degree limit value, and a third temperature limit value, respectively, the minimum opening degree initial value being 0, the second opening degree limit value being greater than the first opening degree limit value, the increased opening degree control comprising: Judging whether the minimum opening is 0, and when the minimum opening is 0, controlling the internal machine electronic expansion valve to be closed; The method comprises the steps of closing an internal electronic expansion valve, increasing the opening of the internal electronic expansion valve at least once after the internal electronic expansion valve is closed, judging whether the opening of the internal electronic expansion valve exceeds the second opening limit value after each time of increasing the opening, controlling the internal electronic expansion valve to resume the superheat degree control if the opening exceeds the second opening limit value, judging whether the difference between the elbow temperature before increasing the opening and the elbow temperature after increasing the opening exceeds the third temperature limit value or whether the difference between the inlet temperature before increasing the opening and the inlet temperature after increasing the opening exceeds the third temperature limit value if the opening exceeds the third temperature limit value, judging that the internal electronic expansion valve is opened when the opening exceeds the second opening limit value, and controlling the internal electronic expansion valve to continue increasing the opening when the opening exceeds the second opening limit value.
5. The multi-split air conditioner of claim 4, wherein the minimum opening storage control comprises: Judging whether the low pressure is lower than the first low pressure limit value; If yes, judging whether the current opening of the internal electronic expansion valve exceeds the first opening limit value, and if yes, storing the first opening limit value to the minimum opening and recovering the superheat degree control, and if not, storing the current opening of the internal electronic expansion valve to the minimum opening and recovering the superheat degree control; if not, directly recovering the superheat control.
6. The multi-split air conditioner of claim 5, wherein the increasing opening degree control further comprises: when the minimum opening is not 0, controlling the internal motor expansion valve to be opened to the minimum opening; The method comprises the steps of opening an internal electronic expansion valve to the minimum opening, increasing the opening of the internal electronic expansion valve at least once, judging whether the opening of the internal electronic expansion valve exceeds the second opening limit value after increasing the opening each time, controlling the internal electronic expansion valve to resume the superheat control if yes, judging whether the difference between the elbow temperature before increasing the opening and the elbow temperature after increasing the opening exceeds the third temperature limit value or whether the difference between the inlet temperature before increasing the opening and the inlet temperature after increasing the opening exceeds the third temperature limit value if not, judging that the internal electronic expansion valve is opened and the superheat control is resumed if yes, and performing closing confirmation judgment and control of the internal electronic expansion valve if no.
7. The multi-split air conditioner of claim 6, wherein the internal motor expansion valve closing confirmation judging and controlling includes: judging whether the difference between the indoor temperature and the second temperature limit exceeds the inlet temperature and whether the difference between the indoor temperature and the second temperature limit exceeds the elbow temperature; and if so, the internal electronic expansion valve resumes the superheat control, and if not, the opening degree of the internal electronic expansion valve is controlled to be continuously increased by the increased opening degree.
8. The variable air conditioner according to claim 7, wherein the indoor unit controller is configured with a second pressure limit value that is smaller than the first low pressure limit value, the indoor unit controller is configured to determine whether the low pressure is lower than the second pressure limit value when the indoor unit electronic expansion valve is in the limit small opening state, and to control the opening degree of the indoor unit electronic expansion valve to be increased to the second opening limit value and to resume the superheat control when the low pressure is lower than the second pressure limit value.
9. The multi-split air conditioner according to claim 1, further comprising an outlet temperature sensor, wherein the outlet temperature sensor is arranged at the outlet and connected with the inner machine controller and used for detecting the outlet temperature and transmitting the outlet temperature to the inner machine controller, the inner machine controller is further provided with a superheat setting value, and the superheat control is used for controlling the suction superheat PI through the difference between the outlet temperature and the inlet temperature and the superheat setting value and controlling the opening degree of the inner machine motor expansion valve.

Description

Multi-split air conditioner Technical Field The invention relates to the technical field of air conditioning, in particular to a multi-connection air conditioner. Background In the traditional control of the expansion valve of the internal machine, the throttle degree can be adjusted by controlling the expansion valve of the internal machine to increase the opening degree or decrease the opening degree during refrigeration. The control quantity is increased, the switching error generated by the control is increased, the situation that the opening of the expansion valve of the inner machine is inaccurate due to long-time control without resetting is caused, the temperature control efficiency is low, the use experience of a user is affected, and when the opening of the expansion valve of the inner machine is smaller, even the situation that the expansion valve of the inner machine is closed to 0 opening or an extremely small opening is caused, the refrigerating capacity of the inner machine is lost, and the use experience of the user is seriously affected. In the prior art, whether the opening of the outdoor electronic expansion valve has errors or not is judged through the target exhaust temperature, the exhaust time and the operating frequency of the compressor, and when the errors exist, the air conditioning system is restarted to reset the outdoor electronic expansion valve, so that the use of a user is affected, the detection and the elimination of whether the errors exist in the outdoor electronic expansion valve are only solved, and the detection and the elimination of whether the errors exist in the electronic expansion valves of one or more indoor units in the multi-split air conditioner cannot be solved. The above information disclosed in this background section is only for enhancement of understanding of the background section of the application and therefore it may not form the prior art that is already known to those of ordinary skill in the art. Disclosure of Invention Aiming at the problems pointed out in the background art, the opening state of the electronic expansion valve of the multi-split air conditioner internal machine is detected, a corresponding control strategy is adopted according to the detection condition, the inefficiency of internal machine refrigeration is avoided, the running reliability of the whole machine is improved, and the use experience of a user is improved. In order to achieve the aim of the invention, the invention is realized by adopting the following technical scheme: In some embodiments of the application, a multi-split air conditioner is provided, which comprises an outdoor unit and a plurality of indoor units, wherein the indoor units comprise an indoor heat exchanger and an internal machine electronic expansion valve, and the indoor heat exchanger is connected with the outdoor unit through the internal machine electronic expansion valve; The indoor unit further comprises an indoor unit controller, an inlet temperature sensor, an elbow temperature sensor and an indoor temperature sensor which are respectively connected with the indoor unit controller; the inlet temperature sensor and the elbow temperature sensor are respectively arranged at the inlet and one of the elbows and used for detecting inlet temperature and elbow temperature and transmitting the inlet temperature and the elbow temperature to the inner machine controller; the internal machine controller is configured to judge whether the internal machine electronic expansion valve is in a limit small opening state according to the inlet temperature, the elbow temperature and the indoor temperature, and control the internal machine electronic expansion valve to increase the opening degree when the internal machine electronic expansion valve is in the limit small opening state, and keep executing overheat degree control when the internal machine electronic expansion valve is not in the limit small opening state. In a specific embodiment, the indoor unit further comprises an air suction superheat acquisition device and a pressure sensor, which are arranged on the outdoor unit, are respectively connected with the indoor unit controller, and are used for acquiring the air suction superheat and the low pressure of the outdoor unit and transmitting the air suction superheat and the low pressure to the indoor unit controller; The internal machine controller is configured with a first temperature limit value, a second temperature limit value, a first opening limit value, a first low-pressure limit value, and a first time period, and is configured to determine whether an opening degree of the internal machine electronic expansion valve is lower than the first opening limit value, whether the low-pressure is lower than the first low-pressure limit value, and whether a difference between the inlet temperature and the suction superheat exceeds the first temperature limit value for the first time period or a differenc