Accelerometer-Based Vibration Damping in Electrical Machines
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Solution Overview
Problem
Existing electrical machines with mechanical bearings face challenges in efficiently suppressing rotor vibrations due to high costs and complexity of using displacement sensors like eddy current or induction sensors for active damping, which limits their ability to operate near critical speeds and reduces bearing lifespan.
Innovation Solution
The use of accelerometers mounted on the stator, particularly on mechanical bearings, provides a cost-effective and reliable vibration sensing solution, allowing for effective active damping by positioning them close to the bearings for clear signal detection and redundancy through multiple accelerometers at different angular positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If displacement sensors such as eddy current sensors or induction sensors are used to sense rotor vibrations, then vibration detection accuracy is improved, but device cost and complexity increase significantly
Solution Approach 1:
The patent replaces expensive displacement sensors with accelerometers, which are considerably cheaper and more robust. The accelerometer is mounted on the stator to detect vibrations transmitted through the mechanical bearing, providing a cost-effective sensing solution that maintains sufficient measurement precision for active damping control.
Solution Approach 2:
The patent substitutes mechanical displacement measurement systems with accelerometer-based vibration sensing. The accelerometer detects vibration accelerations that are integrated to obtain velocity and displacement information, replacing complex mechanical sensor systems with a more robust and cost-effective electronic sensing approach.
2Measurement precision
If displacement sensors are used to measure relative displacement between rotor and stator, then vibration measurement capability is improved, but mounting difficulty and reliability decrease
Solution Approach 1:
Instead of mounting the sensor on the rotor to measure relative displacement, the patent inverts the approach by mounting the accelerometer on the stator. The accelerometer detects vibrations transmitted through the mechanical bearing from the rotor, eliminating the need to access the rotor and making the sensing system more reliable and easier to implement.
3Object-affected harmful factors
If passive vibration damping is used by short-circuiting extra windings, then vibration suppression is achieved, but machine efficiency decreases
Solution Approach 1:
The patent implements active vibration damping using accelerometers to sense vibrations and controllers to dynamically adjust the damping winding currents in real-time. This dynamic control allows the system to suppress vibrations only when needed, maintaining high machine efficiency during normal operation while providing vibration suppression capability when required.
Solution Approach 2:
The patent uses accelerometers to provide feedback on actual vibration levels, which are then processed by controllers to adjust the damping winding currents accordingly. This closed-loop feedback control enables precise vibration suppression while minimizing energy loss, as the damping action is applied only when and where needed based on actual vibration measurements.
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 reduces costs, enhances vibration detection accuracy, and enables more reliable active damping, allowing for operation closer to critical speeds and extended bearing lifespan, while maintaining system performance and adaptability.
Implementation Method 1
at least one accelerometer arranged on the stator, in particular on the mechanical bearing, to detect vibrations from the rotor to the stator through the mechanical bearing
Implementation Method 2
Additional control winding could control the magnetic flux and magnetic forces to damp out rotor lateral vibration
Data Source
Figure 1~2
Figure 3~4
AI summary
An electrical machine comprising: a rotor (1), a stator (2) comprising at least one mechanical bearing (3, 4) via which the rotor (1) is supported by the stator (2), a vibration damper arrangement comprising a winding provided on the stator (2) and configured to suppress stator vibration, a vibration sensor configured to sense machine vibration, a controller (11) which is operatively connected to the vibration damper arrangement and to the vibration sensor and which is configured to control the operation of the vibration damper arrangement on basis of information received from the vibration sensor. The electrical machine is characterised in that the vibration sensor comprises at least one accelerometer (7, 8, 9, 10) arranged on the stator (2).