Air Conditioner Compressor Frequency Control for Fast Startup
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Solution Overview
Problem
Conventional air conditioners experience prolonged startup times for cooling or heating operations due to low probability of liquid backflow to the compressor, leading to extended times to reach set temperatures, which hinders quick startup and reduces performance.
Innovation Solution
An air conditioner with a control unit that dynamically adjusts the compressor's operating frequency using a second protection control, which quickly increases the frequency to necessary levels by reducing the number of target frequencies and maintaining them for shorter periods, thereby shortening the startup time and avoiding compressor-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the activation operation that lowers the operating frequency of the compressor is performed to prevent liquid backflow, then the reliability of the compressor is improved, but the startup time of the cooling or heating operation is extended
Solution Approach 1:
The control unit dynamically adjusts the compressor protection control strategy based on real-time detection of liquid refrigerant accumulation. When liquid accumulation is detected, the system activates the first protection control (lowering operating frequency); when no liquid accumulation is detected, it activates the second protection control (maintaining normal operating frequency). This dynamic adaptation resolves the contradiction by making the system responsive to actual conditions rather than always conserving.
Solution Approach 2:
The system changes the operating parameters of the compressor based on detected conditions. The control unit monitors for liquid refrigerant accumulation and switches between two distinct operating modes: one with reduced operating frequency for protection, and another with normal operating frequency for performance. This parameter change allows the system to optimize between reliability and startup time based on actual refrigerant conditions.
2Productivity
If the operating frequency of the compressor is increased quickly to reach set temperature faster, then the productivity is improved, but the risk of compressor problems due to liquid backflow increases
Solution Approach 1:
The control unit performs preliminary detection of liquid refrigerant accumulation in the suction line before the compressor operates at full speed. By detecting the presence of liquid accumulation in advance and activating appropriate protection control, the system prevents liquid backflow issues before they can occur, enabling safe rapid startup.
Solution Approach 2:
The system implements a feedback mechanism where the control unit continuously monitors for liquid refrigerant accumulation and adjusts the compressor operating frequency accordingly. This closed-loop control allows the system to maintain high productivity when conditions permit while automatically reducing speed when liquid accumulation is detected, thus resolving the contradiction between speed and safety.
Data Source
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AI summary
An air conditioner includes a compressor, the operation frequency of which is variable, and a controller for executing compressor protection control to raise the operation frequency of the compressor to a required operation frequency at the start of the cooling or heating operation. The compressor protection control includes a first protection control and a second protection control. In the first protection control, the operation frequency of the compressor is controlled such that the time period from the activation of the compressor to the time at which the operation frequency reaches the required operation frequency should become relatively long. In the second protection control, the operation frequency of the compressor is controlled such that the time period from the activation of the compressor to the time at which the operation frequency reaches the required operation frequency should be relatively short. The control unit executes the second protection control when the predetermined condition is satisfied at the time of executing the compressor protection control.