Air Conditioner Compressor Frequency Control for Faster Startup
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Solution Overview
Problem
Air conditioners require a longer startup time for the compressor to reach a predetermined frequency, leading to delayed refrigeration and discomfort, especially in high-temperature environments like kitchens.
Innovation Solution
A control method that determines a corner frequency based on the target and minimum operating frequencies of the compressor, allowing for faster frequency-raising at lower frequencies and slower raising at higher frequencies to shorten startup time while ensuring safe and stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the compressor frequency is raised quickly to the target frequency, then the startup time is shortened and refrigeration is accelerated, but the system pressure becomes unstable and safety is compromised
Solution Approach 1:
The patent applies dynamics by making the frequency-raising rate variable rather than fixed. The control method dynamically adjusts the frequency-raising rate based on the current operating frequency relative to the corner frequency. When the current frequency is below the corner frequency, a faster first frequency-raising rate is used; when it reaches or exceeds the corner frequency, a slower second frequency-raising rate is applied. This dynamic adjustment resolves the contradiction by allowing rapid startup initially while ensuring safety near the target frequency.
Solution Approach 2:
The patent changes the parameter of frequency-raising rate based on the operating condition (current frequency relative to corner frequency). By introducing the corner frequency as a reference point and adjusting the frequency-raising rate parameter accordingly, the system achieves both fast startup and safe operation. The parameter change from first frequency-raising rate to second frequency-raising rate occurs at the corner frequency threshold.
2Productivity
If the compressor operates at high frequency immediately, then the refrigeration effect is enhanced, but the system pressure becomes excessively high causing instability
Solution Approach 1:
The control method dynamically adjusts the frequency-raising rate based on system conditions. By using a two-stage frequency-raising approach with the corner frequency as the transition point, the system achieves high productivity when feasible (below corner frequency) while maintaining stability when approaching the target frequency (at or above corner frequency).
Solution Approach 2:
The patent applies beforehand cushioning by slowing down the frequency-raising rate before the compressor reaches the target frequency (when current frequency >= corner frequency). This pre-cautionary measure prevents excessive pressure buildup by reducing the rate of frequency increase in advance, ensuring system stability while still achieving good refrigeration efficiency.
Data Source
AI summary
Provided are a control method for an air conditioner and an air conditioner. The control method includes: determining a corner frequency of a compressor based on a target frequency of the compressor and a minimum operating frequency of the compressor; determining, based on the corner frequency, a first rate and a second rate of frequency-raising of the compressor; and controlling the compressor to start up, the compressor performing the frequency-raising at the first rate when a current operating frequency of the compressor is smaller than the corner frequency, and the compressor performing the frequency-raising at the second rate when the current operating frequency of the compressor is greater than or equal to the corner frequency. The first rate is greater than the second rate.