Rotation speed control method for air conditioner external fan
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Solution Overview
Problem
Existing air conditioning systems face challenges in accurately controlling the rotational speed of external fans, leading to instability and inefficiency due to large speed differences between settings.
Innovation Solution
A method for controlling the rotational speed of an external fan in an air conditioner by monitoring the coil temperature of the outdoor heat exchanger, comparing it to a preset temperature threshold, and adjusting the fan speed accordingly, with the threshold determined by outdoor ambient temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the rotational speed of the DC fan is adjusted based on detected system pressure with multiple speed settings, then the rotational speed can be adapted to current system pressure or coil temperature, but the large rotational speed range (from several hundred to several thousand revolutions) causes large differences in rotational speed between settings, which has a great influence on high and low pressures and is not advantageous for stable operation
Solution Approach 1:
The patent transitions from static multi-level speed settings to dynamic continuous speed adjustment. The control method uses proportional control where the fan speed is adjusted continuously based on the deviation between actual and target coil temperatures, allowing the system to adapt smoothly to varying pressure conditions without abrupt speed changes that destabilize system operation.
Solution Approach 2:
The patent changes the control parameter from discrete speed levels to continuous speed values. By using coil temperature deviation as the control parameter and adjusting fan speed proportionally, the system achieves fine-grained control over the large rotational speed range, preventing large pressure fluctuations that occur with coarse discrete speed settings.
2Ease of operation
If the rotational speed is divided into multiple settings for adjustment, then control is simplified, but the large rotational speed range results in large differences between speed settings that adversely affect system stability
Solution Approach 1:
The control system automatically determines the appropriate fan speed by continuously monitoring coil temperature and calculating the required speed based on temperature deviation. This eliminates the need for manual selection among multiple discrete speed settings while maintaining simple operation through automated proportional control that adapts to real-time system conditions.
Solution Approach 2:
The patent implements closed-loop feedback control where coil temperature is continuously detected and compared with the target temperature. The fan speed is adjusted based on the feedback from this temperature comparison, creating a self-regulating system that maintains stability without requiring manual intervention or discrete speed settings.
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
This method enables stepless speed adjustment of the external fan, improving matching with coil temperature and system pressure, thereby reducing fan speed's influence on the air conditioning system and ensuring stable operation.
Implementation Method 1
an outdoor heat exchanger (3) equipped with the external fan (7)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present disclosure relates to the technical field of air conditioning; in particular, the present disclosure relates to a method for controlling a rotational speed of an external fan of an air conditioner. The present disclosure aims to solve the problem of low adjustment accuracy of external fans of existing air conditioners. To this end, the method for controlling the rotational speed includes: obtaining a coil temperature of the outdoor heat exchanger after the external fan starts; comparing the coil temperature with a preset temperature threshold; and selectively controlling the rotational speed of the external fan to increase or decrease by a rotational speed adjustment amount based on a comparison result; in which the preset temperature threshold is determined based on an outdoor ambient temperature. By selectively controlling the rotational speed of the external fan to increase or decrease by the rotational speed adjustment amount based on the coil temperature of the outdoor heat exchanger and the preset temperature threshold, the control method of the present application can realize a stepless speed adjustment of the external fan, so that the rotational speed of the external fan can match the coil temperature of the outdoor unit, the influence of the rotational speed of the external fan on the air conditioning system can be reduced, and a stable operation of the air conditioning system can be ensured.