Encoderless Vector Control for Fracturing VFD Vibration Suppression
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Solution Overview
Problem
Hydraulic fracturing operations using electric motors powered by variable frequency drives (VFDs) face challenges with smooth operation due to variable loads, unpredictable formation pressures, and fluid dynamics, leading to oscillations, vibrations, and mechanical resonance that can damage equipment.
Innovation Solution
An encoderless vector control scheme for VFDs is implemented, using determined parameters based on turbine generator vibrations to stabilize the electric motor, reducing oscillations and resonance through encoderless vector control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electric motors are used in hydraulic fracturing pumps, then energy efficiency is improved compared to diesel engines, but operation smoothness deteriorates due to oscillations and vibrations
Solution Approach 1:
The patent applies encoderless vector control to dynamically adjust motor control parameters (current, voltage, frequency) in real-time, enabling the motor to adapt to variable loads and maintain smooth operation across the entire speed range while preserving energy efficiency
Solution Approach 2:
The control system continuously monitors motor performance and load conditions, using feedback signals to adjust control parameters dynamically. This closed-loop control eliminates oscillations and vibrations while maintaining optimal energy efficiency
2Speed
If variable frequency drives are used to control electric motors, then speed control capability is improved, but mechanical resonance and vibrations worsen
Solution Approach 1:
The encoderless vector control system dynamically adjusts control parameters based on real-time operating conditions, enabling smooth speed variation across the entire range while actively suppressing mechanical resonance and vibrations through adaptive parameter modification
Solution Approach 2:
The system detects vibrations and resonance conditions, then uses this information to adjust control parameters that actively counteract the harmful effects, converting the problematic vibrations into useful feedback for optimizing motor operation and eliminating resonance
3Stability of the object's composition
If encoderless vector control is implemented, then operation smoothness is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical feedback systems (encoders, sensors) with an encoderless control algorithm that uses electrical signal analysis and mathematical models to achieve the same control objectives, reducing mechanical complexity while maintaining operation smoothness
Solution Approach 2:
The motor control system uses its own electrical characteristics and operating parameters as feedback, eliminating the need for external sensors and encoders. The system self-regulates to maintain smooth operation through intelligent algorithms that process readily available electrical signals
Data Source
AI summary
A system and a method for use of electric motors in fracturing operations are disclosed. The system includes an electric motor, a turbine generator, an encoderless vector control subsystem, and at least one pump. The turbine generator is adapted to generate electric power for the system. The encoderless vector control subsystem is coupled between the turbine generator and the electric motor to control the electric motor using determined parameters that are based in part on vibration induced in a feature associated with the turbine generator. The at least one pump is adapted to receive torque input from the electric motor.