Fan Motor RPM Control Using Current Detection for Constant Air Volume
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Solution Overview
Problem
Conventional air conditioners struggle to maintain constant air volume control due to variations in supply voltage and installation conditions, leading to inconsistent air volume delivery.
Innovation Solution
An air conditioner system that includes a power supply, driving mechanism, current detector, storage, and motor controller to adjust the fan motor's RPM by calculating and adjusting the duty value and current value based on system resistance, ensuring constant air volume control regardless of supply voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan motor RPM is controlled based on static pressure measurement, then air volume control is improved, but the control accuracy deteriorates when supply voltage varies
Solution Approach 1:
The patent changes the control parameter from static pressure alone to a combination of current value and duty value. By using current detection combined with duty cycle information, the system can calculate the actual RPM more accurately regardless of supply voltage variations, thus maintaining control accuracy while improving air volume control
Solution Approach 2:
The patent implements feedback by detecting the actual current consumed by the fan motor and comparing it with expected current values at different RPM levels. This feedback mechanism allows the system to adjust the duty value to achieve target RPM, compensating for supply voltage variations and maintaining reliable control
2Reliability
If additional sensing devices are added to detect supply voltage variations, then control accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by using the fan motor's own current consumption as the sensing parameter. The existing current detector, originally intended for protection purposes, is repurposed to provide RPM information. This eliminates the need for additional RPM sensors or voltage sensing devices, maintaining control accuracy without increasing device complexity
Solution Approach 2:
The patent makes the current detector multi-functional by using it for both motor protection and RPM detection. The same current detection circuit provides information for both safety protection and control purposes, eliminating the need for separate sensing devices and reducing overall system complexity
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
The system effectively maintains constant air volume control within ±10% of the set value, regardless of installation or power supply variations, without the need for additional sensing devices.
Implementation Method 1
a driving mechanism to convert the power, which is supplied by the power supply, into a motor driving voltage depending on a duty value
Implementation Method 2
a current detector to detect a current value input into the fan motor
Data Source
AI summary
The present disclosure is to provide an air conditioner, capable of performing constant air volume control regardless of the variation in a supply voltage and a method for operating the same.