Motor-Generator Control for Stable Turbomachine Power Transitions

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Solution Overview

Problem

Existing turbomachine complexes for power generation experience forced oscillations and inefficient transitions between motor and generator operations, leading to unstable compressor and working fluid pressure, especially with lighter weight turbocompressors, which hinder reliable electrical power generation.

Innovation Solution

A turbomachine control system that couples a motor-generator with a load dissipative device and a power source, using switch complexes and controllers to manage electrical power flow, allowing seamless transitions between motor and generator operations while preventing oscillations by balancing power between the power source, motor-generator, and load dissipative device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the electrical machine is switched between motor and generator operations in known control schemes, then the system can manage power balance, but forced oscillations occur in shaft speed and pressure

Engineering Contradiction:
Improvepower balance managementVSAvoidshaft speed stability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The control system anticipates the transition needs by continuously monitoring shaft speed, turbine torque, and compressor pressure. Before the oscillation can occur, the controller pre-adjusts the electrical machine's operating state and modulates power flow to prevent the destabilizing feedback loop that causes oscillations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback control by monitoring shaft speed, turbine inlet pressure, and electrical power flow. The controller uses this real-time data to dynamically adjust the electrical machine's motor/generator mode and modulate power from the power source and load dissipative device, creating a closed-loop system that actively suppresses oscillations

Inventive Principle:
Principle #23Feedback

2Weight of moving object

If lighter weight turbocompressors with less mechanical inertia are used, then system weight is reduced, but oscillations become more burdensome and reliable power generation is hindered

Engineering Contradiction:
Improveturbocompressor weightVSAvoidpower generation reliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The electrical machine acts as an intermediary between the turbine and compressor, providing electronic inertia through controlled power exchange. The power source and load dissipative device serve as external energy buffers that compensate for the reduced mechanical inertia of lighter turbocompressors, stabilizing shaft speed and preventing oscillations without requiring heavy mechanical components

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stress or pressure

If the electrical machine operates as a motor to boost pressure, then compressor pressure increases, but oscillations between motor and generator modes prevent reliable power generation

Engineering Contradiction:
Improvecompressor outlet pressureVSAvoidpower generation reliability
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The system dynamically adjusts the electrical machine's operating mode based on real-time conditions. Rather than fixed motor or generator operation, the controller continuously modulates the electrical machine's state and power flow to match instantaneous shaft speed and pressure requirements, enabling smooth transitions that maintain both pressure and reliability

Inventive Principle:
Principle #15Dynamics

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 control system smooths transitions between motor and generator operations, prevents oscillations, maintains stable compressor and fluid pressure, and enhances the efficiency of lighter weight turbocompressors for electricity generation, ensuring reliable and efficient power production.

Implementation Method 1

a motor-generator coupled to a shaft of the turbomachine complex

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3384134B1System comprising a turbomachine control system and a turbomachine, method of operating a turbomachine complex
Publication Date: 2023.05.10 GENERAL ELECTRIC CO
  • EP3384134B1 patent drawingFigure 1
  • EP3384134B1 patent drawingFigure 2
  • EP3384134B1 patent drawingFigure 3

AI summary

A turbomachine complex includes at least one motor-generator, at least one power source coupled to the at least one motor-generator, and at least one load dissipative device coupled to the at least one motor-generator. The turbomachine complex is configured to energize the at least one motor-generator through the at least one power source. The turbomachine complex is further configured to simultaneously energize the at least one at least one load dissipative device through the at least one motor-generator.