Fracturing Pump Drive With Constant-Speed Motor and Variable Transmission
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Solution Overview
Problem
Hydraulic fracturing systems powered by diesel engines face challenges such as high fuel costs, emissions, noise, and load factor limitations, while electric motor drive systems require expensive transformers and multiple variable frequency drives (VFDs) for each motor.
Innovation Solution
A hydraulic fracturing system utilizing an electric motor with a constant speed drive shaft and a transmission that adjusts speed ratios to vary pump pressure and flow rate, eliminating the need for dedicated VFDs and transformers by bypassing the motor controller once the motor reaches a predetermined speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If diesel engines are used to power hydraulic fracturing pumps, then the system can operate independently without external power sources, but fuel costs, emissions, noise, and load factor limitations increase
Solution Approach 1:
The patent replaces the diesel engine mechanical power system with an electric motor system. The electric motor is driven by a generator (diesel or gas-powered), separating the prime mover from the pump drive. This substitution eliminates direct engine emissions and noise at the pump location while enabling higher efficiency operation.
2Object-generated harmful factors
If electric motors are used to power hydraulic fracturing pumps, then fuel costs and emissions are reduced, but expensive transformers and multiple variable frequency drives are required
Solution Approach 1:
The patent extracts and eliminates the transformer and variable frequency drive components from the system. By using a generator that directly drives the electric motor at the same frequency and voltage, the system removes the need for voltage transformation and frequency conversion equipment, significantly reducing complexity and cost.
Solution Approach 2:
The patent merges the generator and motor controller functions into a direct mechanical coupling. The generator and electric motor are connected through a simple mechanical linkage without intermediate electrical conversion equipment, combining the power generation and motor drive functions into an integrated system.
3Ease of operation
If variable frequency drives are used to control pump speed, then pump pressure and flow rate control is improved, but system cost and complexity increase
Solution Approach 1:
The patent replaces the electrical variable frequency drive system with a mechanical speed control system. A mechanical transmission device (such as a gearbox or belt drive) is used to control the speed of the electric motor, which in turn controls the pump speed. This mechanical approach achieves the same control objective without complex power electronics.
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 configuration reduces costs and complexity by allowing the electric motor to operate at a constant speed, eliminating the need for dedicated motor controllers and transformers, while providing finer control over pump speed and pressure through transmission adjustments.
Implementation Method 1
a transmission that adjusts speed ratios to vary pump pressure and flow rate
Data Source
AI summary
A system for driving a hydraulic fracturing pump includes an electric motor having a drive shaft configured to rotate at a constant speed and a power source electrically connected to the electric motor. The system also includes a motor controller operably connected to the electric motor via a relay, wherein the motor controller is operably connected to the electric motor by the relay to start the electric motor, and is operably disconnected from the electric motor by the relay once the drive shaft reaches the constant speed. The system further includes a pump coupled to the drive shaft via a transmission, wherein the transmission is configured to transfer rotational energy from the drive shaft to the pump via an output shaft of the transmission, the output shaft of the transmission being configured to drive the pump at varying speeds while the drive shaft rotates at the constant speed.