Rod Pumping Unit Torque Imbalance Control
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Solution Overview
Problem
Rod pumping units experience inefficiencies due to variable load conditions causing torque imbalances in the prime mover, leading to oscillatory responses and sub-optimal operation, as conventional counter-balance adjustments are made after each stroke, resulting in over-adjustment and sub-optimal convergence to the desired imbalance range.
Innovation Solution
A controller that computes motor torque imbalance values for each stroke and engages or disengages a counter-balance adjustment in real-time by using a compressor and bleed valve to adjust pressure within a pressure vessel, ensuring the torque imbalance converges to a desired range during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional counter-balance adjustments are made after each stroke, then the torque imbalance can be corrected, but the adjustment process causes over-adjustment and sub-optimal convergence to the desired imbalance range
Solution Approach 1:
The controller estimates the motor torque imbalance for the upcoming stroke before it occurs, allowing the system to prepare the optimal counter-balance adjustment in advance. This preliminary estimation enables smoother, more precise adjustments without the oscillations caused by reactive post-stroke corrections.
Solution Approach 2:
The system dynamically adjusts the counter-balance based on real-time conditions by estimating torque imbalance for each upcoming stroke and modifying the counter-balance force accordingly. This dynamic approach replaces the static conventional method with a responsive, adaptive system that converges faster to the optimal imbalance range.
2Productivity
If real-time counter-balance adjustment is implemented, then convergence to desired imbalance range is improved, but the system complexity increases due to additional control mechanisms
Solution Approach 1:
The controller uses feedback from torque measurements during each stroke to estimate and correct torque imbalance for the upcoming stroke. This closed-loop feedback mechanism enables real-time adaptation without requiring complex hardware modifications, as the system intelligently processes existing operational data to optimize counter-balance adjustment.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with an intelligent control system that estimates torque imbalance and automatically adjusts the counter-balance. This substitution of mechanical complexity with computational intelligence simplifies the overall system while achieving faster convergence to the desired imbalance range.
3Stability of the object's composition
If the controller estimates torque imbalance for upcoming stroke, then under-shoot and over-shoot of counter-balance force is reduced, but the computational requirements increase
Solution Approach 1:
The controller performs partial computation by estimating torque imbalance using key parameters from the current stroke rather than analyzing every detail. This selective computational approach provides sufficient accuracy for stable counter-balance adjustment without requiring excessive computational resources, achieving a balance between stability and processing power.
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
The real-time adjustment of the counter-balance facilitates efficient convergence of torque imbalance to a desired range, reducing under-shoot and over-shoot of counter-balance force, thereby improving the operating efficiency of rod pumping units.
Implementation Method 1
The compressor is configured to increase a pressure in the pressure vessel when the compressor is engaged
Implementation Method 2
The bleed valve is configured to decrease the pressure in the pressure vessel when the bleed valve is engaged
Data Source
AI summary
A controller for operating a prime mover of a rod pumping unit includes a processor configured to operate the prime mover over a first stroke and a second stroke. The controller is further configured to compute a first motor torque imbalance value for the first stroke and engage adjustment of a counter-balance. The controller is further configured to estimate a second motor torque imbalance value for the second stroke. The controller is further configured to disengage adjustment of the counter-balance during the second stroke upon the second motor torque imbalance value reaching a first imbalance range.