Induction Generator Grid Synchronization Hybrid Fuel Cell

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Solution Overview

Problem

Conventional hybrid fuel cell and turbine generator systems face challenges such as high costs, inefficiencies, increased complexity, and decreased reliability due to the need for synchronous generators, which are not feasible for MW-scale power plants and require additional equipment for synchronization with the electric power grid.

Innovation Solution

A hybrid fuel cell system utilizing a high-temperature fuel cell power plant with an induction machine that can operate as both a motor and a generator, connected directly to the electric power grid without synchronization equipment, using an unfired gas turbine and heat recovery units to optimize energy conversion and reduce complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a synchronous generator is used in MW-scale hybrid power plants, then the system can generate electrical power, but the system requires additional synchronization equipment and speed controls, increasing complexity and cost

Engineering Contradiction:
Improveelectrical power generationVSAvoidsynchronization equipment and speed controls
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the synchronization equipment and speed control mechanisms from the system by using an induction generator instead of a synchronous generator. The induction generator naturally synchronizes with the grid without requiring additional control equipment, thereby removing the complex synchronization subsystem while maintaining power generation capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical synchronization and speed control systems with an electrical solution using an induction generator. The induction generator's inherent electrical coupling with the grid provides automatic synchronization, eliminating the need for mechanical governor controls and synchronization relays that characterize synchronous generator systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Power

If a synchronous generator is used in hybrid power plants, then electrical power can be generated, but the system becomes less reliable due to additional equipment and control requirements

Engineering Contradiction:
Improveelectrical power generationVSAvoidsystem reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

By removing the synchronization equipment, speed controls, and governor mechanisms from the system, the patent eliminates multiple potential failure points. The induction generator's simpler construction without field windings and commutators further enhances reliability by reducing components that require maintenance and can fail.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The induction generator provides self-synchronization with the electrical grid through its inherent electrical coupling, eliminating the need for complex control systems. This self-regulating characteristic improves reliability by removing the need for active control and monitoring of synchronization parameters.

Inventive Principle:
Principle #25Self-service

3Power

If microturbine generators are used in sub-MW hybrid fuel cell plants, then the system can be synchronized to the electric power grid, but the system requires inverter-based power conditioners, increasing complexity and cost

Engineering Contradiction:
Improveelectrical power outputVSAvoidinverter-based power conditioner
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges the power generation and grid synchronization functions into a single induction generator unit. This eliminates the need for separate inverter-based power conditioners that are required with microturbine generators, as the induction generator directly produces grid-compatible electrical output through its inherent electromagnetic coupling with the grid.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If direct connection of synchronous generator to electric power grid is attempted, then synchronization is required, but control complexities increase cost and decrease reliability

Engineering Contradiction:
Improvedirect connection to gridVSAvoidturbine design control
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical control systems required for synchronous generator synchronization with an electrical system using an induction generator. The induction generator's rotor is naturally coupled to the grid through electromagnetic induction, eliminating the need for mechanical governor controls and complex synchronization mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution simplifies the construction and control of MW-scale hybrid power plants, enhances reliability, reduces costs, and increases efficiency by eliminating the need for synchronization equipment and complex turbine designs, allowing direct connection to the electric power grid.

Implementation Method 1

A fuel cell is a device that directly converts chemical energy in the form of a fuel into electrical energy by way of an electrochemical reaction

Methodology Applied
Scientific EffectElectrochemical reaction: Fuel Cell

Implementation Method 2

waste heat from the fuel cell is used by a heat recovery unit to operate the heat engine cycle

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

an induction machine for converting mechanical energy to electrical energy

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2803103B1Electrical generation system and method for a hybrid fuel cell power plant
Publication Date: 2017.11.15 FUELCELL ENERGY INC
  • EP2803103B1 patent drawingFigure 1
  • EP2803103B1 patent drawingFigure 2
  • EP2803103B1 patent drawingFigure 3

AI summary

A hybrid fuel cell system comprising a high temperature fuel cell having an anode section and a cathode section, a gas turbine comprising a compressor cycle for compressing a supply gas and an expansion cycle for expanding one of heated compressed supply gas and a second gas derived from the compressed supply gas to provide mechanical energy to an induction machine, and an induction machine for converting mechanical energy to electrical energy and adapted to output an electrical output.