CN-121985519-A - Cooling system of high-power frequency converter for central air conditioner

CN121985519ACN 121985519 ACN121985519 ACN 121985519ACN-121985519-A

Abstract

The embodiment of the disclosure discloses a cooling system of a high-power frequency converter for a central air conditioner, which is characterized in that the cooling system comprises an inner circulation and an outer circulation, wherein the inner circulation comprises a water pump, the frequency converter and a temperature sensor, the outer circulation comprises an electronic expansion valve, and a controller of the frequency converter is configured to respond to detection of an operating signal of the frequency converter by controlling the electronic expansion valve to operate by receiving coolant temperature information acquired by the temperature sensor, controlling the electronic expansion valve to operate at a first preset opening, controlling the electronic expansion valve to reduce the opening at a second rate, responding to detection that the startup duration of the frequency converter is longer than a third preset duration and the coolant temperature information is longer than a preset low threshold and smaller than a preset high threshold, and controlling the electronic expansion valve to operate at a target proportional integral opening.

Inventors

YU JIE
LIU YANG
LIU MINGHAO
CHEN XU

Assignees

南京天加环境科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260311

Claims (7)

1. A cooling system for a high-power frequency converter of a central air conditioner is characterized in that the cooling system comprises an inner circulation and an outer circulation, wherein, The inner loop includes a frequency converter and a temperature sensor, the outer loop includes an electronic expansion valve, and a controller of the frequency converter is configured to: in response to detecting the working signal of the frequency converter, controlling the electronic expansion valve to operate by the following steps: receiving the coolant temperature information acquired by the temperature sensor; in response to detecting that the startup duration of the frequency converter is less than or equal to a third preset duration, controlling the electronic expansion valve to operate at a first preset opening; In response to detecting that the startup duration of the frequency converter is longer than the third preset duration and the coolant temperature information is higher than a preset high threshold, controlling the electronic expansion valve to increase the opening at a first rate; In response to detecting that the startup duration of the frequency converter is longer than the third preset duration and the coolant temperature information is lower than a preset low threshold, controlling the electronic expansion valve to reduce the opening at a second rate; And in response to detecting that the startup duration of the frequency converter is longer than the third preset duration, the secondary refrigerant temperature information is longer than a preset low threshold value and shorter than a preset high threshold value, determining a target proportional integral opening, and controlling the electronic expansion valve to operate at the target proportional integral opening.
2. The cooling system of claim 1, wherein the internal circulation further comprises a water replenishment tank, a water pump, a frequency converter heat exchanger, an internal circulation coolant and an internal circulation pipe through which the water pump and the frequency converter heat exchanger are sequentially communicated, the internal circulation coolant being filled in the internal circulation pipe, the external circulation further comprises a condenser, an evaporator, an external circulation coolant, a plate heat exchanger and an external circulation pipe through which the condenser, the electronic expansion valve, the evaporator and the plate heat exchanger are sequentially communicated, the external circulation coolant being filled in the external circulation pipe, and the plate heat exchanger being configured to exchange heat between the internal circulation coolant and the external circulation coolant.
3. The cooling system of a high power inverter for a central air conditioner according to claim 1, wherein the controller of the inverter is configured to determine the target proportional-integral opening degree by detecting: receiving output current information of the frequency converter; in response to determining that the output current information meets a first preset condition, determining a first proportional-integral opening according to a first set of proportional-integral parameters, and determining the first proportional-integral opening as the target proportional-integral opening; In response to determining that the output current information meets a second preset condition, determining a second proportional-integral opening according to a second set of proportional-integral parameters, and determining the second proportional-integral opening as the target proportional-integral opening; In response to determining that the output current information does not meet a first preset condition and the output current information does not meet a second preset condition, determining a third proportional-integral opening, and determining the third proportional-integral opening as a target proportional-integral opening.
4. The cooling system for a high power inverter of a central air conditioner of claim 1, wherein the controller is configured to: determining continuous sampling information according to the coolant temperature information; controlling the electronic expansion valve to maintain a first current proportional-integral opening operation in response to determining that the coolant temperature information meets a first preset temperature condition and the continuous sampling information meets a preset descending condition; Controlling the electronic expansion valve to maintain a second current proportional-integral opening operation in response to determining that the coolant temperature information meets a second preset temperature condition and the continuous sampling information meets a preset rising condition; And in response to determining that the coolant temperature information meets the third preset temperature condition, controlling the electronic expansion valve to maintain a third current proportional-integral opening operation.
5. A cooling system for a high power inverter of a central air conditioner according to claim 3, wherein the controller of the inverter is configured to: and controlling the electronic expansion valve to operate at the target proportional-integral opening in response to determining that the coolant temperature information meets a first preset temperature condition and the continuous sampling information does not meet a preset descending condition or in response to determining that the coolant temperature information meets a second preset temperature condition and the continuous sampling information does not meet a preset ascending condition.
6. The cooling system for a high power inverter of a central air conditioner of claim 1, wherein the controller is configured to: and responding to the detection of the standby signal of the frequency converter, controlling the water pump to stop running, and controlling the electronic expansion valve to be closed.
7. The cooling system for a high power inverter of a central air conditioner of claim 1, wherein the controller is configured to: In response to detecting a shutdown signal of the frequency converter, starting timing to acquire timing duration information; controlling the water pump to stop running in response to the fact that the timing duration information is detected to be a first preset duration; and controlling the electronic expansion valve to be closed in response to the fact that the timing duration information is detected to be the second preset duration.

Description

Cooling system of high-power frequency converter for central air conditioner Technical Field The embodiment of the disclosure relates to the technical field of power electronics, in particular to a cooling system of a high-power frequency converter for a central air conditioner. Background In a central air conditioning system, in the working process of a frequency converter, power devices such as an Insulated Gate Bipolar Transistor (IGBT) and a diode and the like generate a great amount of heat loss, and heat dissipation is required to be carried out through an effective cooling system so as to keep the stable operation of the frequency converter. At present, the methods of forced air cooling, liquid cooling (water cooling) and refrigerant cooling are commonly adopted. However, it has been found in practice that when using conventional cooling systems for heat dissipation, the following technical problems are often faced: When the forced air cooling type is used, a fan and an air cooling radiator are needed, the size of the frequency converter is larger, the construction cost is high, when the liquid cooling (water cooling) mode is used, a three-way valve which is needed to be used in the inner circulation is damaged due to frequent switching actions, the three-way valve is needed to be periodically replaced, the outer circulation is needed to be connected with an external cooling water source, the construction cost is increased, when the cooling is used, the situation that the manufacturing difficulty is high is caused because the heat dissipation plate of the frequency converter needs to bear high pressure, the refrigerant quantity is insufficient because the pressure difference is insufficient, the frequency converter is easy to alarm at high temperature, and the electronic expansion valve needs to be matched with complex working conditions, so that the system debugging and maintenance difficulty is increased. The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosed concept and, therefore, it may contain information that does not form the prior art that is known to those of ordinary skill in the art in this country. Disclosure of Invention The disclosure is in part intended to introduce concepts in a simplified form that are further described below in the detailed description. The disclosure is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Some embodiments of the present disclosure propose a cooling system for a high-power inverter of a central air conditioner to solve the technical problems mentioned in the background section above. In a first aspect, some embodiments of the present disclosure provide a cooling system for a high-power inverter of a central air conditioner, characterized in that the cooling system includes an inner loop and an outer loop, wherein the inner loop includes an inverter and a temperature sensor, the outer loop includes an electronic expansion valve, and a controller of the inverter is configured to control operation of the electronic expansion valve by receiving coolant temperature information acquired by the temperature sensor in response to detecting an operation signal of the inverter, controlling operation of the electronic expansion valve at a first preset opening in response to detecting that a start-up duration of the inverter is less than or equal to a third preset duration, controlling operation of the electronic expansion valve at a first preset opening in response to detecting that the start-up duration of the inverter is greater than the third preset duration, and the coolant temperature information is greater than a preset high threshold, controlling operation of the electronic expansion valve at a first rate increasing opening in response to detecting that the duration of the inverter is greater than the third preset threshold, and the duration of the inverter is less than or equal to a preset target value, and controlling operation of the electronic expansion valve at a second preset opening in response to detecting that the start-up duration of the inverter is less than the third preset duration, and the electronic expansion valve is less than the target. Optionally, the internal circulation further includes a water supplementing tank, a water pump, a frequency converter heat exchanger, an internal circulation secondary refrigerant and an internal circulation pipeline, the water supplementing tank, the water pump and the frequency converter heat exchanger are sequentially communicated through the internal circulation pipeline, the internal circulation secondary refrigerant is filled in the internal circulation pipeline, the external circulation further includes a condenser, an evaporator, an external circulation secondary refrigerant, a plate heat exchanger an