Blower Motor Torque Control for Constant Air Flow Under Pressure Changes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor control devices for blower units in air conditioning systems require numerous experiment steps and accurate measurement data to maintain constant air flow, which is challenging due to changes in pressure loss conditions and static pressures, leading to potential air flow errors if measurement errors occur.
Innovation Solution
A motor control device that calculates a torque command as a product of the target air flow divided by the motor speed and the square of the motor speed, allowing for accurate constant air flow control with fewer experiment steps and adaptability to changes in pressure loss conditions and static pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional method using formula (2) with constant knm is used for constant air flow control, then the control can be implemented based on preliminary measurement data, but the accuracy of air flow control deteriorates when pressure loss conditions or static pressure change
Solution Approach 1:
The patent transforms the static control approach into a dynamic one by introducing a dynamic correction value that adapts to changing pressure loss conditions. The correction value is calculated based on the difference between actual and target air flow, and this correction is continuously updated to maintain accurate control despite changes in static pressure or pressure loss conditions. This dynamic adaptation resolves the contradiction by making the control system responsive to environmental changes while maintaining reliability.
Solution Approach 2:
The patent implements a feedback mechanism where the actual air flow is measured and compared with the target air flow to generate a correction value. This feedback loop allows the system to detect deviations caused by pressure loss condition changes and automatically adjust the motor output accordingly. The feedback principle resolves the contradiction by enabling the system to maintain accurate air flow control adaptability through continuous monitoring and correction.
2Measurement precision
If extensive measurement experiments are conducted to obtain accurate blower characteristics, then the control accuracy improves, but the time and complexity of the measurement process increases
Solution Approach 1:
The patent applies partial action by conducting measurement experiments at a single, representative motor speed rather than across the entire operating range. The key insight is that the correction value mechanism compensates for the limited measurement data, allowing accurate control to be achieved with minimal measurement effort. This resolves the contradiction by obtaining sufficient blower characteristic accuracy through partial measurement while significantly reducing the time and complexity of the measurement process.
3Ease of operation
If the motor is controlled at constant torque or constant rotational speed, then the control is simple, but the air flow cannot be maintained at a constant value when pressure loss conditions change
Solution Approach 1:
The patent enables the control system to self-adjust by automatically calculating and applying correction values based on the difference between actual and target air flow. The system serves itself by detecting deviations and implementing corrections without external intervention, maintaining constant air flow while preserving the simplicity of the control approach. This resolves the contradiction by making the system self-correcting, thereby maintaining reliability without sacrificing ease of operation.
Data Source
AI summary
A motor control device which controls a motor for driving a blower unit, comprises a torque command generating section which obtains a motor speed of the motor and generates a torque command which causes an air flow of air supplied from the blower unit to coincide with a target air flow; wherein the torque command generating section is configured to calculate the torque command as a product of a polynomial of variables derived by dividing the target air flow by the motor speed, and a square of the motor speed.