Rotor Secondary Unit Integration for High-Speed Stability
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Solution Overview
Problem
Existing contactless power transmission systems for electric machines face challenges in maintaining speed stability and temperature resistance, especially at high rotational speeds above 15,000 revolutions per minute, due to manufacturing tolerances and air gap maintenance between rotating and stationary parts.
Innovation Solution
The method involves integrating the secondary unit of the power transmission system, including the secondary-side winding and rectifier board, into an end winding cover on the rotor's laminated core, using a filling compound for fixation and centering, and employing a silicone sleeve or annular plug for sealing and centering, ensuring concentric arrangement and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contactless power transmission system is used to supply excitation winding, then electrical power can be transmitted without slip-ring carbon-brush systems and abrasion, but speed stability and temperature resistance become difficult to guarantee at high rotational speeds
Solution Approach 1:
The patent combines the secondary unit of the power transmission system with the rotor structure by integrating it into the end winding cover or rotor body. This merging ensures that the secondary unit and rotor rotate together as a single assembly, maintaining precise air gap positioning and improving speed stability at high rotational speeds above 15,000 rpm.
Solution Approach 2:
The patent employs preliminary centering and fixation actions during manufacturing. The secondary unit is pre-centered on the rotor shaft using centering elements before final fixation with adhesive or mechanical means. This preliminary action ensures proper positioning is established before operation, preventing air gap variations during high-speed rotation.
2Ease of manufacture
If secondary unit is separately mounted on rotor, then assembly flexibility is improved, but manufacturing tolerances and air gap maintenance become more difficult to control
Solution Approach 1:
The patent integrates the secondary unit with the rotor structure by providing a fixation connection between them. This can be achieved by integrating the secondary unit into the end winding cover or directly into the rotor body, ensuring they move as a single unit and maintaining consistent air gap dimensions throughout operation.
Solution Approach 2:
The patent introduces intermediary elements such as centering rings, positioning features, or fixation structures that mediate between the secondary unit and rotor shaft. These intermediaries ensure precise positioning and maintain manufacturing tolerances while allowing for practical assembly procedures.
3Productivity
If rotor is designed for high speed operation above 15,000 rpm, then productivity and power output are improved, but temperature resistance and structural integrity become challenging
Solution Approach 1:
The patent applies different material properties and thermal management approaches to different parts of the rotor. The secondary unit and surrounding structures are designed with specific thermal characteristics suitable for their local thermal environments, allowing the rotor to operate at high speeds while managing temperature distribution across different components.
Solution Approach 2:
The patent employs composite construction for the rotor, combining materials with different thermal and mechanical properties. This allows the rotor structure to withstand high rotational speeds while maintaining temperature resistance, as different materials can be selected for specific functions such as thermal conductivity, strength, and thermal expansion characteristics.
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 approach provides a cost-effective manufacturing method for rotors with high temperature resistance and speed stability, maintaining the air gap and ensuring reliable power transmission at high speeds by integrating the secondary unit into the end winding cover, enhancing the rotor's structural integrity and thermal management.
Implementation Method 1
employing a silicone sleeve or annular plug for sealing and centering, ensuring concentric arrangement and thermal conductivity
Implementation Method 2
a secondary-side winding of the rotary transformer for arrangement on one end face of the rotor of the electric machine and for converting the magnetic flux that changes over time into an AC voltage
Implementation Method 3
a rectifier board with a rectifier circuit for rectifying the AC voltage
Data Source
AI summary
A method for manufacturing a rotor for an electric machine with a contactless power transmission system, wherein an end winding cover is arranged on one end face of a laminated core of the rotor. The invention provides that a secondary unit (SEC) of the power transmission system is integrated in the end winding cover and, as a result, after the end winding cover has been arranged, the secondary unit (SEC) is held on the rotor indirectly via the end winding cover.