Superconducting Wind Generator Torque Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional direct drive generators for wind turbines face challenges with low torque density and excessive weight at power ratings above 3 MW, leading to the need for unreliable indirect drives with gearboxes, which are not suitable for long-term service.
Innovation Solution
A superconducting direct drive generator with a stationary field winding and rotating armature, utilizing racetrack-shaped superconducting coil magnets cooled to cryogenic temperatures, housed in a cryostat with a thermal shield and evacuated interior, allowing for high torque density and reduced weight, enabling direct drive of wind turbines at higher power ratings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional direct drive generators are used for wind turbines with power ratings above 3 MW, then the generator can be directly connected to the turbine blades without a gearbox, but the generator becomes too heavy for the wind turbine tower
Solution Approach 1:
The patent changes the physical state of the field winding material from conventional copper to superconducting material, which fundamentally alters the electrical resistance parameter from finite to near-zero. This parameter change enables the field winding to generate much stronger magnetic fields with significantly less material, directly reducing the generator's weight while maintaining high power output capability for direct drive applications
Solution Approach 2:
The patent employs composite material structures including superconducting coils combined with cryogenic insulation materials and structural supports. The field winding uses superconducting material composite that combines high critical current density with mechanical strength, allowing the generator to achieve high torque density without excessive weight, resolving the contradiction between direct drive reliability and generator weight
2Weight of moving object
If the field winding uses superconducting coil magnets cooled to cryogenic temperatures, then the generator achieves high torque density and reduced weight, but the system requires a cryostat with thermal shield and evacuated interior
Solution Approach 1:
The patent implements a nested structure where the superconducting coil magnets are placed inside an inner cryostat chamber, which is surrounded by a thermal shield, which in turn is enclosed by an outer cryostat housing. This nested arrangement efficiently organizes the cryogenic system components, allowing the complex cryostat structure to be integrated compactly without proportionally increasing the generator's overall weight, thus resolving the contradiction between weight reduction and structural complexity
Solution Approach 2:
The thermal shield acts as an intermediary component between the cold superconducting coils and the warmer external environment. It intercepts thermal radiation and conducts heat away through the vacuum insulation, protecting the superconducting material from thermal damage. This intermediary structure enables the cryogenic system to function reliably while keeping the overall design compact and manageable
3Device complexity
If conventional direct drive generators are used, then the structure is simpler without superconducting components, but the torque density is low and the generator becomes too heavy
Solution Approach 1:
The patent fundamentally changes the electrical resistance parameter of the field winding from conventional finite resistance to near-zero superconducting state. This parameter change enables the field winding to carry much higher current densities without resistive losses, generating significantly stronger magnetic fields and thus achieving high torque density. The complex superconducting structure is justified by the substantial improvement in torque production capability
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 superconducting generator achieves high torque density and light weight, enabling efficient generation of 10 MW or more of electrical power while maintaining reliability and compactness, suitable for economical installation on wind turbine towers.
Implementation Method 1
the field winding include superconducting coil magnets
Implementation Method 2
racetrack-shaped superconducting coil magnets cooled to cryogenic temperatures
Implementation Method 3
a thermal shield forming an annular chamber suspended by a torque tube in an evacuated interior of the housing
Implementation Method 4
in an evacuated interior of the housing
Implementation Method 5
a non-rotating annular field winding coaxial with the armature and separated by a gap from the armature, wherein the field winding include superconducting coil magnets
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A generator (22) including: an annular armature (24) connectable to rotate with blades (18) of a wind turbine (10); an annular stationary field winding assembly (26) coaxial with the armature and separated by a gap from an inside surface of the armature, wherein the field winding include superconducting coils (68), and support structure connectable to an upper region of a tower (12) of the wind turbine.