Motor Device Constant Air Flow Control via Proportional Current
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Solution Overview
Problem
Existing motor control systems for blowers require complex processes to maintain a constant air flow rate, which can be inconvenient and inefficient.
Innovation Solution
A motor device that uses vector control to maintain a constant air flow rate by controlling the rotation speed and q-axis driving current proportionally, utilizing a position/speed acquirer, multiplier, current controller, Clarke transformer, Park transformer, subtractor, controller, inverse Park transformer, inverse Clarke transformer, and inverter to calculate and control a flow-rate-constant target driving current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vector control is used to maintain constant air quantity by calculating from rotation speed and driving current, then the air quantity can be kept constant, but the control process becomes complex
Solution Approach 1:
The patent extracts the essential relationship for constant air quantity control from complex vector control calculations. By identifying that air quantity Q is proportional to the product of rotation speed ω and q-axis current iq (Q ∝ ω×iq), the invention isolates this key relationship and builds control around it, eliminating unnecessary computational complexity while maintaining air quantity constancy.
Solution Approach 2:
The patent changes the control parameter from complex multi-variable vector control to a simplified proportional relationship between rotation speed and q-axis current. By establishing that iq should be proportional to ω (iq ∝ ω) to maintain constant air quantity, the invention transforms the control approach into a more manageable parameter relationship that achieves the same goal with less complexity.
2Measurement precision
If multiple transformers and controllers are used for vector control, then precise motor control is achieved, but the device structure becomes complex
Solution Approach 1:
The patent makes the control system multi-functional by having the same controller perform both the simplified proportional control calculations and the traditional vector control transformations (Clarke and Park transforms). This universal approach allows the system to maintain precise motor control while using a single integrated controller rather than multiple separate devices, reducing overall system complexity.
Data Source
AI summary
A motor device configured to convey a fluid by driving a fan with a motor includes a position/speed acquirer configured to acquire a current rotation angle and a current rotation speed of the motor, a multiplier configured to calculate a flow-rate-constant target driving current by multiplying the rotation speed and a flow rate coefficient, and a current controller configured or programmed to control a motor driving current by setting, as a control target, the flow-rate-constant target driving current and to control a flow rate of the fluid to be maintained at a constant value which depends on the flow rate coefficient.