Stepper Valve Flow Control With Low-Current Hold
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Solution Overview
Problem
Conventional flow rate adjusting devices using stepping motors generate excessive heat during stop operations due to continuous excitation current application, leading to inefficiency and potential overheating.
Innovation Solution
A control method that adjusts the excitation current value during motion and stop operations of the stepping motor, using a lower current during stops to reduce heat generation, and varies stop periods based on flow rate differences to optimize thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excitation current of the same current value is output from the motor driver to the stepping motor in both motion and stop operations, then the valve body position can be reliably held during stop operation, but the stepping motor and motor driver generate excessive heat during stop operation
Solution Approach 1:
The patent applies dynamics by making the excitation current value variable rather than fixed. The motor driver dynamically adjusts the excitation current based on the operational state: using a first current value during motion operations and a second current value (lower than the first) during stop operations. This dynamic adjustment allows the system to maintain reliable position holding during stops while reducing heat generation compared to continuous full-current operation.
Solution Approach 2:
The patent changes the parameter of excitation current from a constant value to a variable value that depends on the operational phase. By switching between a first current value (for motion) and a second current value (for stop, lower than the first), the system optimizes both position holding reliability and thermal management. This parameter change resolves the contradiction by adapting the current level to the actual operational requirements.
2Stability of the object's composition
If excitation current is continuously applied to hold the valve body position during stop operation, then position stability is maintained, but power consumption increases
Solution Approach 1:
The system dynamically adjusts excitation current based on operational state. During stop operations, the motor driver outputs a second current value that is lower than the first current value used during motion, while still maintaining sufficient torque to hold the valve body position. This dynamic current adjustment reduces power consumption during stops compared to continuous full-current application, while preserving position stability.
Solution Approach 2:
The excitation current parameter is changed from a constant high value to a variable value that is lower during stop operations. By switching to the second current value (lower than the first) during stops, the system maintains position stability through adequate holding torque while significantly reducing power consumption during idle periods.
3Measurement precision
If the motor driver outputs excitation current during stop operation to prevent valve body motion, then positioning accuracy is maintained, but the system efficiency decreases
Solution Approach 1:
The motor driver dynamically adapts the excitation current output based on whether the system is in motion or stop state. During stop operations, it outputs a second current value (lower than the first) that maintains sufficient holding torque for positioning accuracy while reducing energy waste. This dynamic behavior improves overall system efficiency by avoiding unnecessary full-power current delivery during idle stop periods.
Solution Approach 2:
The excitation current parameter switches between a first current value (for motion) and a second current value (for stop, lower than the first). This parameter change enables the system to maintain positioning accuracy during stops through adequate holding torque while improving overall efficiency by reducing energy consumption during non-motion periods.
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
Effectively suppresses heat generation in stepping motors and motor drivers during stop operations, enhancing efficiency and reducing power consumption while maintaining flow rate control.
Implementation Method 1
a stepping motor configured to rotate about the axis to move the valve body along the axis and a motor driver configured to generate excitation current used for driving the stepping motor
Implementation Method 2
The motor driver can hold the drive shaft of the stepping motor at a predetermined position to prevent the rotation thereof by outputting excitation current to the stepping motor even when stopping the valve body without moving the same
Implementation Method 3
a flow rate adjusting portion configured to move a valve body in a direction closer to or away from a valve hole to adjust the flow rate of a fluid passing through the valve hole
Implementation Method 4
a flow metering portion configured to measure a flow rate of a fluid flowing into a measurement flow channel from an inflow port and flowing through the measurement flow channel
Data Source
AI summary
Provided is a flow rate adjusting device including: a flow metering portion; a flow rate adjusting portion; a flow rate setting unit; and a control unit. The flow rate adjusting portion has a stepping motor that moves a valve body along an axis and a motor driver that outputs excitation current to the stepping motor. The control unit controls the flow rate adjusting portion to move the valve body by an amount so that a measured flow rate value measured by the flow metering portion matches a set flow rate value, the amount corresponding to a difference between both the values, controls the motor driver to generate excitation current of a first current value during an operation to move the valve body, and controls the motor driver to generate excitation current of a second current value lower than the first current value during an operation to stop the valve body.