Permanent Magnet Rotor Assembly for Passive Over-Voltage Attenuation
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Solution Overview
Problem
Conventional permanent magnet generators (PMGs) face challenges in maintaining stable voltage output across varying rotational speeds and loads, often requiring a narrow operating point near current saturation to prevent over-voltage, which compromises efficiency and robustness.
Innovation Solution
A PMG system with a rotor assembly that passively attenuates voltage output by sliding between a maximum coupling and misaligned position in response to acceleration above an impulse threshold, using a biasing member like a coil spring and linear guides to maintain optimal coupling until high acceleration occurs, thereby preventing over-voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the generator is designed to operate at a narrow operating point near current saturation to prevent over-voltage, then over-voltage compliance is improved, but efficiency deteriorates
Solution Approach 1:
The rotor assembly is designed to dynamically adjust its position along the shaft based on rotational speed. At normal operating speeds, the rotor maintains optimal magnetic coupling with the stator for efficient power generation. When rotational speed exceeds a threshold causing over-voltage conditions, the centrifugal force automatically shifts the rotor axially to reduce magnetic coupling, thereby passively attenuating the voltage output without requiring active control systems
Solution Approach 2:
The system uses its own operational parameters (rotational speed and resulting voltage) to automatically regulate its output. The rotor assembly self-regulates the voltage by shifting its position in response to centrifugal forces generated during over-speed conditions, eliminating the need for external control mechanisms and enabling the system to serve its own voltage regulation needs
2Stability of the object's composition
If the rotor is physically fixed to the stator for stable voltage output, then voltage stability is improved, but adaptability to varying loads and speeds deteriorates
Solution Approach 1:
The rotor assembly transitions from a static, fixed position to a dynamic, adjustable position along the shaft. The rotor can slide axially to change its magnetic coupling with the stator, allowing the system to adapt to varying load conditions and rotational speeds while maintaining stable voltage output through passive attenuation when needed
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 solution allows for improved efficiency and robustness by enabling operation over a wider range, reducing the need for narrow design points and independent over-voltage protection, making the system more efficient and cost-effective.
Implementation Method 1
a rotor assembly configured to be magnetically coupled to the stator and to rotate relative to the stator to induce the voltage
Implementation Method 2
The rotor assembly can include a biasing member configured to bias the rotor to a maximum coupling position. The biasing member can be configured to hold the rotor in the maximum coupling position until the rotor accelerates at or above the impulse acceleration threshold
Data Source
AI summary
A permanent magnet generator (PMG) system can include a stator configured to output a voltage, and a rotor assembly configured to be magnetically coupled to the stator and to rotate relative to the stator to induce the voltage. The rotor assembly can be configured to passively attenuate the voltage output from the stator in response to acceleration of the rotor assembly at or above an impulse acceleration threshold.