Stepper Motor Valve Actuator Current Control
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Solution Overview
Problem
Existing valve systems with stepper motors face issues of noise, vibrations, and reduced lifespan due to unnecessary oversteps required to compensate for mechanical tolerances, which also lead to increased electrical energy consumption.
Innovation Solution
The stepper motor is driven using multiple electrical current levels, with distinct levels for different stages of valve movement and compression, optimizing the number of steps to ensure tightness without unnecessary oversteps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stepper motor is driven with a defined number of steps including oversteps to compensate for mechanical tolerances, then tightness between the valve plunger and valve seat is ensured, but bumping noise and vibrations occur
Solution Approach 1:
The patent applies parameter changes by varying the electrical current level during different phases of the valve actuation cycle. The driver operates the stepper motor at a first electrical current level during closing operation, reduces to a second lower current level during the oversteps, and then increases to a third current level during opening operation. This dynamic current adjustment allows the motor to maintain sufficient force for tightness while reducing the harmful effects of oversteps.
2Reliability
If the stepper motor is driven with oversteps to absorb mechanical tolerances, then tightness is provided, but electrical energy consumption increases
Solution Approach 1:
The patent reduces electrical energy consumption during oversteps by operating the stepper motor at a reduced second electrical current level that is lower than both the first and third current levels. This current reduction during the overstep phase minimizes energy waste while still achieving the necessary valve tightness through the cumulative effect of all steps.
3Reliability
If the stepper motor is driven with oversteps to compensate for tolerances, then tightness is ensured, but the life-time of the valve is reduced
Solution Approach 1:
The patent extends valve lifetime by dynamically adjusting the electrical current level during operation. By reducing the current to a second level during oversteps and only applying higher current levels (first and third levels) when necessary for tightness and opening operations, the motor experiences reduced thermal and mechanical stress during the most damaging phases, thereby extending overall valve lifespan.
4Ease of operation
If the stepper motor is driven at a constant electrical current level for all steps, then simplicity of control is maintained, but unnecessary oversteps cause noise, energy waste and reduced valve life
Solution Approach 1:
The patent introduces dynamic control by varying the electrical current level according to the actuation phase. The driver switches between three distinct current levels based on the valve's operational state: a first level during closing, a reduced second level during oversteps, and a third level during opening. This dynamic approach maintains control simplicity through automated phase detection while eliminating the harmful effects of constant high-current operation during oversteps.
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
This approach ensures reliable valve sealing, reduces noise and vibrations, and extends the lifespan of the valve while minimizing energy consumption.
Implementation Method 1
a stepper motor as actuator... drives the stepper motor in such a way that the stepper motor provides a defined number of steps in order to move the valve plunger
Implementation Method 2
a flexible element assigned to the valve plunger needs to be compressed in order to provide tightness between the valve plunger and the valve seat
Data Source
Figure 1
Figure 2~4
AI summary
Method for operating a valve comprising at least one valve seat, a valve plunger and a stepper motor for moving the valve plunger from a first position into a second position in which the valve plunger is pressed against a valve seat and for compressing a flexible element assigned to the valve plunger in said second position, whereby the stepper motor is driven in such a way that the stepper motor provides a defined number of steps (NTOTAL) in order to move the valve plunger into the second position and to compress the flexible element, wherein the stepper motor is driven is such a way that for a first number of steps (N1) of said defined number of steps (NTOTAL) the stepper motor is operated at a first current level (I1); for a subsequent second number (N2) of steps of said defined number of steps (NTOTAL) the stepper motor is operated at a second current level (I2) being lower than the first current level (I1); for a subsequent third number of steps (N3) of said defined number of steps (NTOTAL) the stepper motor is operated at a third current (I3) level being higher than the second current level (I2).