Control apparatus of electrically driven valve, electrically driven valve, and electrically driven valve unit using the same
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Solution Overview
Problem
Electrically driven valves in refrigeration systems face challenges in accurately positioning the valve element due to hysteresis caused by backlash in the power transmission path, making precise flow rate control difficult.
Innovation Solution
A control apparatus for electrically driven valves that includes a nonvolatile storage unit to store the amount of hysteresis, allowing the control unit to adjust the drive pulses of the stepping motor based on this stored value, ensuring accurate positioning and flow rate control by accounting for hysteresis during direction changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a gear mechanism is used to reduce rotational movement in the power transmission path, then the valve element can be driven with sufficient force, but hysteresis occurs due to backlash making high-accuracy positioning difficult
Solution Approach 1:
The control unit performs preliminary action by storing the hysteresis amount in advance in a nonvolatile storage unit, and then compensates for it when calculating the number of pulses to be input to the stepping motor, thereby achieving accurate positioning despite the presence of backlash in the gear mechanism
Solution Approach 2:
The control unit changes the parameter of pulse number by adding the stored hysteresis amount to the target pulse number, thereby adjusting the driving pulses to compensate for backlash and achieve accurate valve element positioning
2Manufacturing precision
If the number of pulses is increased to overcome backlash, then positioning accuracy may improve, but energy consumption increases
Solution Approach 1:
The control unit optimizes the pulse number parameter by precisely calculating the minimum required pulses (target pulse number plus stored hysteresis amount) to achieve accurate positioning without excessive energy consumption
Solution Approach 2:
The system uses stored hysteresis data as feedback to adjust the pulse number, ensuring that the minimum necessary energy is consumed to achieve the desired positioning accuracy
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
Enables precise flow rate control by compensating for hysteresis, improving the accuracy of valve positioning and maintaining efficient operation in refrigeration systems.
Implementation Method 1
a stepping motor configured to be operated by entering a drive pulse
Implementation Method 2
a driving mechanism configured to drive the valve element by a driving force output from the stepping motor
Data Source
AI summary
An electrically driven valve includes a valve element configured to move to a direction approaching a valve seat or to a direction separating therefrom, a stepping motor configured to be operated by entering a drive pulse, a driving mechanism configured to drive the valve element by a driving force output from the stepping motor, a nonvolatile storage unit configured to store an amount of hysteresis, and a control unit configured to drive the stepping motor according to an operation instruction information entered from an exterior.