Wind Generator Stator Rewinding for Inter-Turn Failure Reduction
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Solution Overview
Problem
High-power wind generators, such as those rated at 2.3 MW, experience premature inter-turn failures due to inadequate insulation and design, leading to a mean time between failures of 5-7 years, which is short of the desired 15 years or more.
Innovation Solution
The solution involves replacing the original OEM stator core with a new one having fewer stator slots, increasing the number of coil turns, and using a trapezoidal wedge to hold coil windings, thereby reducing circulating and eddy current losses without the need for inter-coil transpositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the original OEM stator core is replaced with a new one having fewer stator slots and increased coil turns, then copper and eddy current losses are reduced by 23%, but the manufacturing complexity increases due to redesign requirements
Solution Approach 1:
The patent applies parameter changes by modifying the stator core design parameters: reducing the number of stator slots from the original configuration to 48 slots, and increasing the number of coil turns per phase. This parameter optimization reduces copper losses and eddy current losses by 23% while maintaining the rated power output of at least 2.3 MW, directly resolving the technical contradiction between energy loss reduction and design complexity.
2Reliability
If elaborate inter-turn insulation is applied to prevent inter-turn failures, then reliability improves, but manufacturing time and complexity increase
Solution Approach 1:
The patent extracts and eliminates the need for elaborate inter-turn insulation by fundamentally changing the winding configuration. By increasing the number of coil turns and reconfiguring the stator slots, the design inherently prevents inter-turn failures without requiring complex multi-layer insulation structures like quad film conductor covering with mica film turn tape, thus improving reliability while reducing manufacturing complexity.
Solution Approach 2:
Instead of adding more insulation to prevent failures, the patent inverts the approach by designing a winding configuration that inherently prevents inter-turn failures. The increased number of coil turns and optimized slot configuration create a more robust electrical design that eliminates the need for excessive insulation layers, achieving reliability through design rather than protective additions.
3Loss of energy
If the number of stator slots is reduced and coil turns are increased, then circulating current losses are reduced, but the winding manufacturing time should be minimized
Solution Approach 1:
The patent optimizes the parameter combination of 48 stator slots with increased coil turns per phase to reduce circulating current losses while maintaining manufacturing efficiency. This specific parameter configuration achieves a 23% reduction in copper and eddy current losses compared to conventional designs, and the standardized slot-coil arrangement facilitates efficient winding manufacturing processes.
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 design reduces copper, circulating, and eddy current losses by 23%, increases the reliability and dependability of the wind generator, and reduces the time required for manufacturing and winding by approximately 30%, while eliminating the need for elaborate inter-turn insulation.
Implementation Method 1
increasing the number of coil turns forming each coil winding from a first value to a second value, wherein the first value is associated with the first stator core and the second value is associated with the second stator core... reduces copper, circulating, and eddy current losses by 23%
Data Source
AI summary
Methods for repairing electric machines, such as wind generators, and stators implemented thereof. One method includes replacing a first stator core with a second stator core, wherein the second stator core has fewer stator slots than the first stator core, and wherein the stator slots are configured to receive coil windings. The method includes increasing a number of coil turns forming each coil winding from a first value to a second value, wherein the first value is associated with the first stator core and the second value is associated with the second stator core. The electric machine with the second stator core has rated power output at least as high as the electric machine with the first stator core.