Fan motor controller and associated control method
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Solution Overview
Problem
Conventional motor control methods for fans, such as those in air conditioning systems, face challenges in stabilizing motor speed convergence due to varying gain values, leading to slow convergence and unstable operation when air flow values change, especially in real-world environments with clogged filters or vent adjustments.
Innovation Solution
A motor controller with an air flow calculation section and a speed command generation section that adjusts the speed command based on a comparison calculation value, using a ratio or difference with the predetermined air flow command, and integrates feedback control to stabilize air flow convergence, with set ranges for compensation and limiting the speed command within minimum and maximum values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a small gain value is used in the conventional motor control method, then the motor speed changes gradually and stably, but the convergence time becomes excessively long
Solution Approach 1:
The patent applies dynamics by making the gain value variable rather than fixed. The controller dynamically adjusts the gain based on the absolute value of the air flow command: using a first gain when the air flow command is small and a second gain (larger than the first) when the air flow command is large. This dynamic adjustment allows the system to converge quickly when large changes are needed while maintaining stability during fine adjustments.
2Speed
If a large gain value is used in the conventional motor control method, then the motor speed converges quickly, but the motor speed fluctuates and fails to stably converge
Solution Approach 1:
The patent makes the gain value dynamic by switching between two different gain values based on the air flow command magnitude. When the air flow command is large, a larger gain is used to achieve fast convergence. When the air flow command is small, a smaller gain is used to ensure stable convergence without fluctuations. This resolves the contradiction by adapting the gain to the operational context.
Solution Approach 2:
The patent changes the control parameter (gain value) based on the operating conditions (air flow command magnitude). By switching between a first gain and a second gain according to the air flow command threshold, the system optimizes both convergence speed and stability for different operational scenarios.
3Productivity
If the air flow command changes significantly, then the system needs to respond quickly, but the motor speed becomes unstable and oscillates
Solution Approach 1:
The patent dynamically adjusts the gain based on the air flow command magnitude. When the air flow command changes significantly (large value), a larger gain is applied to enable rapid response. When the air flow command is small (near the target value), a smaller gain is applied to ensure stable convergence. This dynamic parameter adjustment resolves the contradiction between fast response and stability.
Solution Approach 2:
The control parameter (gain) is changed based on the air flow command value. The controller switches between a first gain and a second gain according to whether the air flow command exceeds a predetermined threshold, enabling the system to adapt its response characteristics to the magnitude of the command change.
Data Source
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AI summary
A motor controller (8a) of the present invention comprises units (6-10) which obtain information indicative of a motor speed (ω) and information indicative of motor torque (T), an air flow calculation section (11) which calculates an air flow (Q) of a fan (1) based on the motor speed (ω) and the motor torque (T); and a speed command generation section (12) which generates a speed command (ω*) of a motor (3) such that the air flow (Q) coincides with the predetermined air flow command (Q*).