Hydraulic Log Motor-Generator for Turbomachine Drive
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Solution Overview
Problem
Turbomachines, such as gas turbine engines, face challenges with weight and complexity due to separate generators for driving rotors and generating electric power, particularly with variable frequency starter generators that require complicated shafting and gearing to accommodate varying rotational speeds.
Innovation Solution
A hydraulic log system with adjustable wobbler plates and a port plate that controls fluid flow between high and low pressure areas, allowing for consistent rotational output and enabling both start-up and power generation modes with minimal additional weight and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate generators are used to drive rotors and generate electric power, then the turbomachine can perform both starting and power generation functions, but the weight and complexity of the system increases
Solution Approach 1:
The patent combines the motor and generator functions into a single integrated motor-generator unit. The stator and rotor are shared between motor mode (where electrical power drives mechanical rotation for starting) and generator mode (where mechanical rotation from the turbomachine generates electrical power). This merging eliminates the need for separate generators, reducing weight and complexity while maintaining dual-mode operation capability.
Solution Approach 2:
The motor-generator unit is designed to perform multiple functions: it operates as a motor during starting to drive the compressor rotor, and as a generator during power generation to produce electrical power from the turbomachine's rotation. The same physical components (stator, rotor, windings) serve both purposes, making the system universal and eliminating the need for separate dedicated generators for each function.
2Adaptability or versatility
If variable frequency starter generators are used to accommodate varying rotational speeds, then the turbomachine can operate across different speed ranges, but complicated shafting, gearing, clutching, or valving is required
Solution Approach 1:
The patent replaces complex mechanical transmission systems (shafting, gearing, clutching) with an electrical control system. The motor-generator uses electrical windings and magnetic fields to control rotation and speed, eliminating the need for mechanical gears and clutches. The controller adjusts electrical power frequency and voltage to match the turbomachine's varying rotational speed, providing variable speed operation through electrical rather than mechanical means.
Solution Approach 2:
The motor-generator's electrical parameters (frequency, voltage, current) are dynamically adjusted to match the turbomachine's varying rotational speed. During starting, the motor operates at frequencies that produce the required rotational speeds for acceleration. During generation, the generator produces electrical power at frequencies proportional to the turbomachine speed. This parameter adjustment allows variable speed operation without mechanical transmission complexity.
3Adaptability or versatility
If electrical usage equipment is designed to operate under variable frequency input, then the system can accommodate varying turbomachine speeds, but the equipment weight, envelope, power losses, and cost increase
Solution Approach 1:
The controller continuously monitors the turbomachine's rotational speed and adjusts the motor-generator's electrical output frequency accordingly. During generation mode, the controller ensures the electrical power frequency is proportional to the measured rotational speed, providing feedback control that maintains proper frequency alignment without requiring the electrical equipment to be designed for the full range of variable frequencies, thereby reducing equipment weight and complexity.
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 hydraulic log system provides a consistent rotational input to the motor-generator, ensuring a consistent frequency electric power output and reducing weight and complexity by accommodating varying rotational speeds, thus enhancing efficiency and reducing costs.
Implementation Method 1
the valve controls flow of fluid from a higher pressure area of the hydraulic log to a lower pressure area of the hydraulic log
Implementation Method 2
a first plurality of pistons each having a stroke that is adjusted with a first wobbler plate to provide a rotational output from the hydraulic log that is different than a rotational input to the hydraulic log
Data Source
Figure 1~2
Figure 3
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AI summary
An example arrangement for driving a turbomachine includes an input shaft (48) that is configured to rotate a rotor (40) of the turbomachine through a hydraulic log (58) and gear differential (46) rotatably coupled to the input shaft. A motor-generator (54) is rotatably coupled to the differential. The motor-generator has a motor mode of operation and a generator mode of operation. The motor-generator is configured to drive the input shaft through the hydraulic log and differential when the motor-generator is in the motor mode of operation. The input shaft is configured to drive the motor-generator through the hydraulic log and differential when the motor-generator is in the generator mode of operation.