Brushless Motor Stator Damping via Resistive Wire Loops
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Solution Overview
Problem
Existing methods for damping moving aerodynamic surfaces in motors often require complex electronic circuitry, which complicates devices and can lead to catastrophic flutter oscillations during actuator or power supply failures, necessitating a simpler and more reliable damping solution.
Innovation Solution
Integration of hollow channels with resistive wire loops within the stator of a permanent magnet brushless motor, where the resistive wire intercepts the magnetic flux to generate a damping torque related to rotational speed, with a disengageable mechanism using a switch to control and cancel the damping effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex electronic circuitry is used for damping, then damping control is improved, but device complexity increases
Solution Approach 1:
The patent extracts the damping function from complex electronic circuitry and implements it through a passive mechanical field circuit. The field winding serves dual purposes: generating magnetic field for motor operation and providing damping through resistive elements, eliminating the need for separate electronic damping circuits.
Solution Approach 2:
The field winding is designed to perform multiple functions: generating the magnetic field necessary for motor operation and providing damping control. The same winding that enables motor function also serves as the damping mechanism through its inherent resistance and the addition of external resistors, reducing overall device complexity.
2Reliability
If additional damping components are added, then damping reliability is improved, but device weight increases
Solution Approach 1:
The patent merges the damping components with the existing motor structure. External resistors are integrated into the field circuit, and the damping function is combined with the field winding system, avoiding the need for separate dedicated damping components that would increase weight.
Solution Approach 2:
The field winding and associated resistors serve dual purposes: enabling motor operation through magnetic field generation and providing damping control. This multi-functionality eliminates the need for separate damping components, thereby avoiding additional weight.
3Reliability
If damping is always active, then safety against flutter oscillations is improved, but energy efficiency deteriorates
Solution Approach 1:
The damping mechanism is designed to be dynamically controllable rather than constantly active. The field current, which naturally varies during motor operation, controls the damping effect. Additionally, the circuit allows selective engagement of external resistors based on operational conditions, enabling damping to be active only when needed.
Solution Approach 2:
The damping effect is controlled by changing electrical parameters - specifically the field current magnitude and the resistance values in the field circuit. By adjusting these parameters based on operational needs, the system achieves damping only when required, maintaining energy efficiency while ensuring safety against flutter oscillations.
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
Provides a reliable damping effect without complex electronics, ensuring safety against flutter oscillations and optimizing efficiency by minimizing thermal losses and weight, while maintaining damping functionality even in power failures.
Implementation Method 1
the resistive wire intercepts the magnetic flux to generate a damping torque related to rotational speed
Implementation Method 2
the resistive wire intercepts the magnetic flux to generate a damping torque
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An electrical motor comprising a stator 11, said stator comprising a back iron 14, a plurality of teeth extending therefrom, and windings 18 wound around said teeth; a rotary body 13 comprising permanent magnets 12 positioned between said stator 11 and said rotary body 13; said rotary body 13 being coaxially rotatable relative to the stator 11 about a central axis 15; means for rotating said rotary body 13 about said central axis of rotation 15 relative to said stator 11, and wherein said back iron 14 of said stator further comprises a first loop of electrical resistive wire 20, 40, 80 extending therein.