Ventilation Blower Control Using Interpolated Motor Operating Points
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ventilation blowers struggle with accurate and fine air volume control due to error factors such as cogging torque, iron loss, and air leakage, which lead to discrepancies between target and actual air volumes. Additionally, storing angular velocities and torque current values for various operation points increases storage device capacity and cost.
Innovation Solution
A ventilation blower system that includes an inverter main circuit, a motor body with a stator and rotor, a motor control circuit, and a storage device. The system stores angular velocities and torque current values at specific operation points and uses these values to calculate the required parameters for achieving target air volumes, allowing for accurate and fine air volume control without increasing storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If angular velocities and torque current values for various operation points are stored to achieve accurate air volume control, then air volume control precision is improved, but storage device capacity and cost increase
Solution Approach 1:
The patent extracts only the essential parameters needed for control (angular velocities and torque current values at specific operation points) and stores them in a compact format. By selecting key operation points rather than storing all possible data points, the storage requirement is minimized while maintaining sufficient control accuracy for different installation environments.
Solution Approach 2:
The patent changes the control parameters from storing complete air volume characteristics to storing angular velocities and torque current values at discrete operation points. This parameter transformation allows the system to achieve accurate air volume control through interpolation and calculation rather than direct lookup, significantly reducing storage requirements.
2Device complexity
If ideal control based on theoretical formulas is used, then device complexity is reduced, but air volume control precision deteriorates due to error factors
Solution Approach 1:
The patent incorporates feedback mechanisms where the actual motor current and rotation speed are measured and compared with the stored operation point data. The system uses this feedback to adjust control commands, compensating for error factors like cogging torque and iron loss that are not accounted for in theoretical formulas, thereby improving precision without significantly increasing complexity.
Solution Approach 2:
The patent performs preliminary characterization by measuring and storing the actual operation points (angular velocities and torque current values) under various conditions before deployment. This preliminary action captures real-world error factors and installation environment variations, allowing the compact control system to compensate for these effects without complex real-time calculations.
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 enables accurate and fine air volume control while reducing costs associated with increased storage capacity, effectively addressing the limitations of existing ventilation blower technologies.
Implementation Method 1
an inverter main circuit including a plurality of switching elements to be switched to convert direct-current power into three-phase alternating-current power
Implementation Method 2
a motor body including a stator and a rotor and to be driven by the inverter main circuit
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A ventilation blower includes an inverter main circuit, a motor body including a stator and a rotor to be driven by the inverter main circuit, a motor control circuit that controls the inverter main circuit, and a storage device. The storage device stores an angular velocity of the rotor and a torque current value at a first operation point at which to obtain a first air volume on a first load characteristic, and the angular velocity and the torque current value at a second operation point at which to obtain a second air volume on the first load characteristic, the second air volume being different from the first air volume. The motor control circuit calculates, from the angular velocity and the torque current value at the first operation point and the angular velocity and the torque current value at the second operation point, the angular velocity and the torque current value at a third operation point at which to obtain a third air volume on the first load characteristic, and causes the inverter main circuit to drive the motor body with the angular velocity and the torque current value at the third operation point.