Electromagnet Armature Position Control for Reciprocating Pump Noise Reduction
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Solution Overview
Problem
Existing control methods for electromagnetically driven reciprocating pumps are inefficient due to hard impacts and noise, and fail to accurately account for changes in environmental conditions and non-linear electromagnet behavior, leading to suboptimal operation.
Innovation Solution
A controller that uses a mathematical model of the electromagnet to estimate the magnet armature position based on measured state variables, including voltage, current, and magnetic flux, with pre-recorded non-linear properties to adjust the applied voltage and modulate the pulse duration, allowing for precise control of the magnet armature's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnetic coil is energized until the end of the movement of the magnet armature and even beyond, then a complete stroke is achieved under all operating conditions, but the magnet armature strikes hard with high noise and low efficiency
Solution Approach 1:
The controller switches off the magnetic coil before the magnet armature reaches its end position, anticipating the completion of stroke based on pre-stored current profiles. This preliminary action prevents the hard impact and noise while ensuring complete stroke achievement under all operating conditions.
Solution Approach 2:
The system uses the measured coil current as feedback to determine magnet armature position indirectly. By comparing the measured current with pre-stored reference profiles corresponding to different positions, the controller accurately predicts armature position and switches off the coil at the optimal moment, avoiding hard impact while maintaining reliable stroke completion.
2Measurement precision
If the coil current is used to determine magnet armature position, then position information is obtained, but environmental changes such as supply voltage and coil temperature affect the quality of the control method
Solution Approach 1:
The system compensates for environmental changes by adapting the comparison between measured and reference current profiles. The reference profiles are stored for different operating conditions, and the system selects the appropriate reference profile based on current environmental parameters, maintaining accurate position determination despite variations in supply voltage and temperature.
Solution Approach 2:
The control system dynamically adapts to changing environmental conditions by using real-time current measurements and comparing them with stored reference profiles that account for different operating conditions. This dynamic approach allows the system to maintain measurement precision across varying supply voltages and temperatures.
3Measurement precision
If a mathematical model of the electromagnet is used to estimate armature position, then non-linear properties are accounted for, but the complexity of the control increases
Solution Approach 1:
Instead of implementing a complex real-time mathematical model, the system creates simplified reference copies of current profiles for different armature positions and operating conditions. These reference profiles are stored in memory, and the controller simply compares measured current against these pre-computed references, achieving accurate position estimation without the computational complexity of real-time non-linear modeling.
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 significantly reduces noise and improves efficiency by accurately predicting the magnet armature's position and movement, accounting for non-linear properties and environmental changes, resulting in smoother operation and reduced wear.
Implementation Method 1
Electromagnetically driven reciprocating pumps consist of an electromagnet and a fluid displacement unit
Implementation Method 2
The electromagnet and displacement unit are usually inseparably connected to one another by common components
Implementation Method 3
if the restoring spring moves the magnet armature back unbraked when the electromagnet is switched off
Data Source
Figure 1
AI summary
A control of an electromagnetically driven reciprocating piston influences the speed of a magnet armature by switching the voltage supplied to the electromagnet dependent on the position of the magnet armature. In the process, the position of the magnet armature should not be measured but rather determined from state variables of the electromagnet. This is achieved in that a processor (11) calculates the electric resistance of the magnet coil (5) from the electric voltage values and electric current values measured by the measuring device (13), calculates the temporal change of the linked magnetic flux in the electromagnet (2) from the electric voltage, the electric current, and the electric resistance of the magnet coil (5), calculates the linked magnetic flux in the electromagnet (2) from an older magnetic flux and the temporal change, determines the position of the magnet armature (7) from the linked magnetic flux in the electromagnet (2) and the electric current flowing through the magnet coil (5), and switches the electric voltage at the magnet coil (5) by means of the switch device (12) depending on the position of the magnet armature (7). Reciprocal piston pumps of the aforementioned type and the electric control thereof are used to pump and/or meter fuel and reagents in vehicles and mobile work machines.