CN-115727518-B - Operation control method and system for multistage variable frequency air conditioner system

CN115727518BCN 115727518 BCN115727518 BCN 115727518BCN-115727518-B

Abstract

The invention discloses an operation control method and an operation control system for a multi-stage variable frequency air conditioning system, which comprise the steps of setting the lowest operation frequency for each air conditioning unit in the multi-stage variable frequency air conditioning system, comparing the real-time air outlet temperature with a preset target temperature, regulating and controlling the working frequency of the air conditioning units according to the comparison result, judging whether the current working frequency of a front-stage unit is larger than the lowest operation frequency for any two adjacent air conditioning units, judging whether the output frequency of a rear-stage unit is larger than X% of the rated frequency if not, controlling the front-stage unit to operate at the lowest operation frequency if not, and controlling the front-stage unit to gradually unload according to a preset time period until the air conditioning unit is stopped.

Inventors

LUO YIMING
ZHU LI
LI RUITAO
CHEN HAO
REN RUIBO
ZHAO XIANGYOU

Assignees

广东欧科空调制冷有限公司

Dates

Publication Date: 20260508
Application Date: 20221208

Claims (10)

1. The operation control method of the multistage variable frequency air conditioning system is characterized by comprising the following steps of: setting the lowest operation frequency for each air conditioning unit in the multi-stage variable frequency air conditioning system, wherein the lowest operation frequency is greater than the lowest limit frequency allowed by the air conditioning unit; detecting the real-time air outlet temperature of the air conditioning unit; Comparing the real-time air outlet temperature with a preset target temperature, and regulating and controlling the working frequency of the air conditioning unit according to the comparison result; For any two air conditioning units adjacent to each other, judging whether the current working frequency of the preceding unit is greater than the lowest working frequency, if not, then, Judging whether the output frequency of the rear-stage unit is greater than X% of the rated frequency, wherein X is greater than or equal to 50, if so, controlling the front-stage unit to run at the lowest running frequency, and if not, controlling the front-stage unit to gradually reduce load according to a preset time period until the machine is stopped.
2. The operation control method of a multistage variable frequency air conditioning system according to claim 1, wherein heat exchange mediums in a plurality of the air conditioning units respectively have different specific enthalpy change sections, and the specific enthalpy change sections of a preceding-stage unit and a subsequent-stage unit in two air conditioning units adjacent to each other have overlapping sections.
3. The operation control method of the multistage variable frequency air conditioning system according to claim 1, wherein the synchronous loading of the rear-stage unit is controlled in the process of controlling the stage-by-stage load shedding of the front-stage unit to the shutdown.
4. The operation control method of the multistage variable frequency air conditioning system according to claim 1, wherein X is 50-85.
5. An operation control system of a multi-stage variable frequency air conditioning system, wherein each air conditioning unit in the multi-stage variable frequency air conditioning system is provided with a lowest operation frequency, the lowest operation frequency is greater than a lowest limit frequency allowed by the air conditioning unit, the operation control system comprises: the temperature detection module is used for detecting the real-time air outlet temperature of the air conditioning unit; The comparison module is used for comparing the real-time air outlet temperature with a preset target temperature; The regulation and control module is used for regulating and controlling the working frequency of the air conditioning unit according to the feedback of the comparison module; the first judging module is used for judging whether the current working frequency of a front-stage unit in any two adjacent air conditioning units is greater than the lowest working frequency; the second judging module is used for judging whether the output frequency of the subsequent unit is greater than X% of the rated frequency or not when the judging result of the first judging module is negative, and X is more than or equal to 50; And the execution module is used for controlling the pre-stage unit to run at the lowest running frequency when the judging result of the second judging module is yes, and controlling the pre-stage unit to gradually reduce load according to a preset time period until the machine is stopped when the judging result of the second judging module is no.
6. The operation control system of the multistage variable frequency air conditioning system according to claim 5, wherein heat exchange mediums in a plurality of the air conditioning units have different specific enthalpy change sections, respectively, and the specific enthalpy change sections of a preceding-stage unit and a subsequent-stage unit in two air conditioning units adjacent to each other have overlapping sections.
7. The operation control system of the multi-stage variable frequency air conditioning system according to claim 5, wherein the execution module controls the synchronous loading of the rear-stage unit in the process of gradually reducing load to stop of the front-stage unit.
8. The operation control system of the multi-stage variable frequency air conditioning system according to claim 5, wherein X is more than or equal to 50 and less than or equal to 85.
9. An operation control system of a multi-stage variable frequency air conditioning system, comprising: One or more processors; A memory; And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the multi-stage variable frequency air conditioning system operation control method of any one of claims 1 to 4.
10. A computer-readable storage medium, comprising a computer program executable by a processor to perform the multi-stage variable frequency air conditioning system operation control method according to any one of claims 1 to 4.

Description

Operation control method and system for multistage variable frequency air conditioner system Technical Field The invention relates to the technical field of multi-stage combined operation air conditioner control, in particular to a multi-stage variable frequency air conditioner system operation control method and system. Background In the application of the full fresh air low-temperature dehumidification air conditioning system, a multistage variable-frequency direct expansion refrigerating system is generally adopted for grading treatment, and the environment air is dehumidified and cooled in a relay mode. At present, the running frequency of the variable frequency compressor cannot realize 0-100% of full-section output, so that the oil return reliability of the variable frequency compressor is ensured, the running frequency is not allowed to be lower than 20% (the lowest limit), and the lubricating oil of an oil pool of the compressor is ensured to be sufficient by forced frequency raising at intervals when the running frequency of the variable frequency compressor is lower than 20% in order to improve the reliability of a refrigerating system. When the external environment temperature is at the critical point of the set target outlet air temperature, the operation frequency of the compressor is required to be low enough, so that the smooth transition of the system is ensured, and obviously, the operation frequency is in conflict with the operation state of the compressor. In this way, in the transitional season, when the ambient temperature is located at a critical point (near a preset target air outlet temperature point), severe vibration can occur in the front-stage refrigeration system, so that adjacent rear-stage refrigeration systems are mutually influenced, the compressor is frequently started and stopped, severe vibration is generated on the surface temperature of the heat exchanger, and low-pressure faults occur after the rear-stage heat exchanger is frozen and collapse is caused by multiple low temperatures. Disclosure of Invention The invention aims to provide a multistage variable frequency air conditioning system operation control method and system for avoiding system oscillation caused by frequent start and stop of a preceding air conditioning unit. In order to achieve the above object, the present invention discloses a method for controlling operation of a multistage variable frequency air conditioning system, comprising: Setting the lowest operation frequency for each air conditioning unit in the multi-stage variable frequency air conditioning system, wherein the lowest operation frequency is greater than the lowest limit frequency allowed by the air conditioning unit; detecting the real-time air outlet temperature of the air conditioning unit; Comparing the real-time air outlet temperature with a preset target temperature, and regulating and controlling the working frequency of the air conditioning unit according to the comparison result; For any two air conditioning units adjacent to each other, judging whether the current working frequency of the preceding unit is greater than the lowest working frequency, if not, then, Judging whether the output frequency of the rear-stage unit is greater than X% of the rated frequency, wherein X is greater than or equal to 50, if so, controlling the front-stage unit to run at the lowest running frequency, and if not, controlling the front-stage unit to gradually reduce load according to a preset time period until the machine is stopped. Preferably, the heat exchange mediums in the air conditioning units respectively have different specific enthalpy change intervals, and the specific enthalpy change intervals of the front-stage unit and the rear-stage unit in the two adjacent air conditioning units have overlapping areas. Preferably, the pre-stage unit is controlled to be synchronously loaded in the process of gradually unloading to stopping. Preferably, X is more than or equal to 50 and less than or equal to 85. The invention also discloses a multi-stage variable frequency air conditioning system operation control system, each air conditioning unit in the multi-stage variable frequency air conditioning system is provided with a lowest operation frequency, the lowest operation frequency is larger than the lowest limit frequency allowed by the air conditioning unit, and the operation control system comprises: the temperature detection module is used for detecting the real-time air outlet temperature of the air conditioning unit; The comparison module is used for comparing the real-time air outlet temperature with a preset target temperature; The regulation and control module is used for regulating and controlling the working frequency of the air conditioning unit according to the feedback of the comparison module; the first judging module is used for judging whether the current working frequency of a front-stage unit in any two adjacent air conditioning