Variable Power Generator for Marine Hydrokinetic Turbines
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Solution Overview
Problem
Current marine hydrokinetic turbines face challenges in converting variable rotational speed to constant speed and efficiently generating constant frequency electrical power, leading to inefficiencies and high failure rates in gearboxes and electronics, which limits the harnessing of hydrokinetic energy from rivers and oceans.
Innovation Solution
The implementation of a variable power generator (VPG) with a spur/helical gear assembly and a speed converter that adjusts the relative axial overlap between the rotor and stator to control speed and torque, allowing for mechanical synchronization of variable input to constant output, eliminating the need for gearboxes and reducing costs, weight, and potential downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a gearbox is used to convert variable rotational speed to constant speed, then speed conversion is achieved, but reliability deteriorates due to gearbox failures
Solution Approach 1:
The patent removes the gearbox from the system entirely and replaces it with a variable speed generator that directly converts variable rotational speed to constant frequency electrical output. This extraction of the problematic gearbox component eliminates the reliability issues while maintaining the speed conversion function through electromagnetic conversion instead of mechanical gearing.
Solution Approach 2:
The patent substitutes the mechanical gearbox system with an electromagnetic system using a variable speed generator. The generator uses electromagnetic induction to convert variable mechanical rotational speed from the turbine into constant frequency electrical energy, replacing the mechanical speed conversion mechanism with an electromagnetic field-based conversion process.
2Reliability
If a variable frequency converter is used to control output power frequency, then frequency control is achieved, but device complexity increases
Solution Approach 1:
The patent merges the frequency control function directly into the generator design by using a variable speed generator that inherently produces constant frequency output. This combines the power generation and frequency control functions into a single integrated component, eliminating the need for separate variable frequency converters and reducing overall system complexity.
3Productivity
If traditional hydrokinetic turbines are used, then energy harvesting is achieved, but efficiency deteriorates due to variable frequency output
Solution Approach 1:
The patent replaces the traditional mechanical direct-drive or gearbox system with a variable speed generator that uses electromagnetic conversion. This substitution allows the turbine to operate efficiently across a range of rotational speeds while consistently producing grid-compatible constant frequency electrical energy, maximizing energy harvest from variable water flows without efficiency losses from speed-matching constraints.
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 enables the production of constant frequency electrical power from variable hydrokinetic energy sources, enhancing efficiency, reducing maintenance needs, and increasing the reliability of marine hydrokinetic energy generation systems.
Implementation Method 1
a variable power generator (VPG) with a spur/helical gear assembly and a speed converter to adjust the relative axial overlap between the rotor and stator
Data Source
AI summary
A marine hydrokinetic electric power generator comprises one of a stator and a rotor which is adjustably movable through an infinite number of positions from being proximate to one another so that their magnetic fields overlap mostly to a position such that the rotor is most distant from the stator and has little overlap of magnetic field strength. Hatch and speed control may be also provided by a spur/helical gear assembly of sun and planetary gear sets referred to herein as a Transgear™ gear assembly. The variable (or fixed) power generator in operation may comprise one of a rotor and a stator being out of phase with one another by an angle, for example, the one of the rotor or the stator leading or lagging the other and the phase angle, frequency or voltage of output power to a power grid corrected responsive to inputs from the power grid and the marine hydrokinetic turbine.