Medium-Voltage Power Converter Eliminates Transformers in Wind Nacelles
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Solution Overview
Problem
Large wind plants face challenges with high connection costs and mechanical stability issues due to the need for parallel connections of low-voltage converter modules, which increase nacelle weight and dimensions, and require substantial space and support structures, complicating logistics and increasing costs.
Innovation Solution
A multi-level power converter system that eliminates the need for transformers, allowing direct connection to collector circuits and providing multiple isolated supply powers to power stages, reducing weight, size, and cost, while meeting power quality and fault-ride through requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If low-voltage converter modules are connected in parallel to handle high power levels, then the power conversion capability is improved, but the nacelle weight and dimensions increase significantly
Solution Approach 1:
The patent transforms the voltage level parameter from low-voltage (690V) to medium-voltage (34.5kV) operation. By changing the voltage parameter, the system achieves the same power conversion capability with dramatically reduced current, allowing single-module operation instead of parallel connections, thus reducing nacelle weight and eliminating the need for multiple cables per phase
Solution Approach 2:
The patent segments the power conversion function into a single integrated medium-voltage converter module rather than using multiple low-voltage modules in parallel. This segmentation principle is applied in reverse - consolidating what would be separate low-voltage modules into one unified medium-voltage solution, reducing the number of components and connections required
2Power
If low-voltage converter modules are connected in parallel, then the power handling capacity is improved, but the connection costs and cable requirements increase
Solution Approach 1:
By changing the voltage parameter from low-voltage to medium-voltage, the system reduces the current magnitude, which directly reduces cable size requirements and connection complexity. The medium-voltage converter requires fewer and smaller cables compared to parallel low-voltage connections, thereby reducing connection costs and simplifying installation
3Ease of manufacture
If the electrical conversion system is placed in the nacelle, then the connection costs are reduced, but the nacelle weight and space requirements increase
Solution Approach 1:
The patent uses medium-voltage operation to reduce the physical size of the converter module. Although the converter is placed in the nacelle, the medium-voltage design requires significantly less space compared to an equivalent low-voltage parallel-module system, because it needs only a single module rather than multiple parallel connections with associated cooling, control, and connection infrastructure
4Power
If multiple parallel converter modules are used, then the power conversion capability is improved, but the device complexity and support structures increase
Solution Approach 1:
By operating at medium-voltage, the patent eliminates the need for parallel module configurations. A single medium-voltage converter module provides the same power conversion capability as multiple low-voltage modules, thereby simplifying the system architecture, reducing control complexity, and eliminating the need for complex parallel-connection support structures and synchronization systems
Data Source
AI summary
In one embodiment, the present invention includes a turbine to generate mechanical energy from kinetic energy, a generator coupled to the turbine to receive the mechanical energy and to output multiple isolated supply powers, and multiple power stages each coupled to the generator. Each of the power stages may receive at least one of the isolated supply powers.