Non-Through Shaft Rotor Structure for Hypercritical Speed Stability
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Solution Overview
Problem
Existing motor-compressor sets with rotary electrical machines and through shafts are limited by hypercritical rotation speeds, leading to instability and reduced efficiency due to metadamping issues, which restrict the usable speed domain and compression ratio.
Innovation Solution
A rotor with a non-through shaft design featuring two half-shafts enclosing a cylindrical magnetic mass with periodic cells, configured to prevent metadamping propagation over a specific frequency range, allowing higher rotation frequencies without instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotation speed is increased to improve efficiency and power output, then the efficiency and compression ratio improve, but metadamping appears causing loss of stability and system destruction
Solution Approach 1:
The rotor is segmented into multiple laminated plates stacked together to form the magnetic mass, with each plate contributing to the overall structural integrity while distributing metadamping effects. This segmentation allows the rotor to operate stably at hypercritical speeds by preventing the propagation of destabilizing vibrations through the entire rotor structure.
2Power
If the rotation speed is increased to improve power output, then the power development increases, but the transmission line passes through hypercritical speed domain causing loss of stability
Solution Approach 1:
The rotor design changes the physical parameters of the magnetic mass by using laminated plates with specific material properties, thicknesses, and stacking arrangements. These parameter changes modify the metadamping characteristics to allow stable operation in the hypercritical speed domain, enabling higher power output without stability loss.
3Ease of manufacture
If a through shaft is used to simplify the rotor design, then the manufacturing is easier, but the peripheral speed is limited to 200 m/s due to stress concentration
Solution Approach 1:
The invention extracts and removes the through shaft from the rotor design, replacing it with a non-through shaft configuration where the magnetic mass is supported by bearings at the ends. This extraction eliminates the stress concentration problem associated with through shafts, allowing peripheral speeds to exceed 200 m/s while maintaining manufacturing feasibility through the modular laminated plate structure.
Data Source
AI summary
The rotor for an electrical machine with a non-through shaft intended to drive a transmission line comprises two half-shafts enclosing a cylindrical magnetic mass.The magnetic mass comprises at least two adjacent identical cells, the cells being configured to prevent the propagation of metadamping in the rotor over a range of excitation frequencies of the transmission line, the rotation frequency range of the transmission line being hypercritical.