Variable-frequency drive cooling device, cooling method and air conditioning apparatus
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Solution Overview
Problem
Conventional cooling methods for variable frequency drives in refrigeration units are inadequate under high-temperature and low-frequency conditions, leading to overheating risks due to insufficient refrigerant flow, especially in air-cooled chillers operating at temperatures between 43° C. to 52° C. and when compressors operate at low frequencies for extended periods.
Innovation Solution
A variable frequency drive cooling device with a bypass and ejector system, along with multiple electric valves and branch pipes, dynamically controls refrigerant flow based on environmental, drive cabinet, and compressor conditions to ensure stable cooling, using an ejector to enhance refrigerant flow under harsh conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cooling methods (fans or standard refrigerant flow) are used for variable frequency drives, then the cooling system is simple, but the cooling effectiveness is insufficient under high-temperature and low-frequency conditions
Solution Approach 1:
The cooling system is segmented into multiple independent refrigerant flow paths: a first refrigerant flow path for standard cooling operations, and a second refrigerant flow path specifically for high-temperature and low-frequency conditions. Each path has dedicated flow control valves, allowing the system to select the appropriate cooling mode based on operating conditions, thereby improving reliability without requiring complete system redesign.
Solution Approach 2:
The system dynamically adjusts the refrigerant flow path selection based on real-time operating conditions (temperature and frequency). Flow control valves automatically switch between the first and second refrigerant flow paths, enabling adaptive cooling that responds to changing environmental conditions, thus ensuring effective cooling while maintaining system simplicity through automated control.
2Temperature
If additional heat dissipation devices (fans) are added to cool the variable frequency drive, then cooling is provided, but the device complexity and space requirements increase
Solution Approach 1:
The cooling function for the variable frequency drive is merged with the existing refrigeration cycle system. Instead of adding separate fan-based cooling devices, the invention utilizes the refrigerant from the compression system to provide cooling through dedicated flow paths and heat exchange structures, thereby achieving drive cooling without increasing overall device complexity or requiring additional power-consuming components.
Solution Approach 2:
The refrigerant circulation system serves multiple functions: it cools both the refrigeration load and the variable frequency drive. By designing the system so that the refrigerant can be directed to different locations (evaporator for refrigeration, drive cabinet for electronics cooling), the system achieves multi-functionality, eliminating the need for separate cooling systems and reducing overall complexity.
3Use of energy by moving object
If refrigerant flow is reduced under low-frequency operation, then energy consumption decreases, but cooling effectiveness for the variable frequency drive deteriorates
Solution Approach 1:
The system changes the refrigerant flow parameters (flow rate, pressure, temperature) based on operating conditions. Under low-frequency operation, the flow control valve adjusts refrigerant parameters to maintain adequate cooling capacity despite reduced compressor output, ensuring that energy consumption is optimized while drive temperature control remains effective.
Solution Approach 2:
The system incorporates temperature sensors and flow control valves that provide feedback control. When the drive temperature approaches critical levels during low-frequency operation, the feedback mechanism activates to increase refrigerant flow to the drive cooling path, ensuring temperature control is maintained while minimizing unnecessary energy consumption during normal operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures effective cooling of variable frequency drives by stabilizing refrigerant flow, preventing overheating, and maintaining optimal performance under high-temperature and low-frequency operating conditions.
Implementation Method 1
The bypass is equipped with a second electric valve and an ejector. One end of the third branch pipe communicates with the ejector, and the other end of the third branch pipe communicates with an inlet of the first electric valve. The third branch pipe is equipped with a third electric valve.
Implementation Method 2
the first branch pipe is configured to cool a variable frequency drive cabinet, and the second branch pipe is configured to cool a variable frequency drive module
Implementation Method 3
introducing a portion of refrigerant from the refrigeration cycling system to cool the variable frequency drive and lower the temperature thereof
Implementation Method 4
an outlet conduit equipped with a first electric valve; the bypass is equipped with a second electric valve; the third branch pipe is equipped with a third electric valve; the first branch pipe is further equipped with a fourth electric valve; the second branch pipe is provided with a fifth electric valve
Data Source
AI summary
The present disclosure provides a variable frequency drive cooling device, a cooling method, and an air conditioning apparatus. The variable frequency drive cooling device includes an inlet conduit, an outlet conduit equipped with a first electric valve, a first branch pipe and a second branch pipe connected in parallel between the inlet conduit and the outlet conduit, the first branch pipe being configured to cool a variable frequency drive cabinet, and the second branch pipe being configured to cool a variable frequency drive module; a bypass, one end of the bypass communicating with an outlet pipe a compressor, and another end of the bypass communicating with an outlet of the first electric valve in the outlet conduit, the bypass being equipped with a second electric valve and an ejector; and a third branch pipe, one end of the third branch pipe communicating with the ejector, and another end of the third branch pipe communicating with an inlet of the first electric valve, the third branch pipe being equipped with a third electric valve.