Air-Coupled Resonant Transformer Gap Sensing for Contactless Power
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Solution Overview
Problem
Existing contactless power transmission systems in machine tools face challenges in accurately measuring and monitoring the distance between stationary and movable parts, particularly due to thermal expansion and limited space, which can lead to potential damage from accidental contact or insufficient power transfer.
Innovation Solution
A contactless power transmission method and electrical power supply circuit that utilize an air-coupled transformer with a series resonant circuit and a controller to adjust the frequency of the primary electrical voltage, allowing for accurate measurement of the distance between the stator and rotor by maintaining resonance conditions without the need for external probes or devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the distance between stator and rotor is reduced to improve power transfer efficiency, then power transmission efficiency is improved, but the risk of accidental contact and damage increases
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the distance between stator and rotor using a laser measuring device and automatically adjusting the spindle position or alerting the operator when the distance approaches unsafe thresholds, thus preventing accidental contact while maintaining optimal power transfer
Solution Approach 2:
The patent employs protective casings and safety margins that are designed in advance to prevent direct contact between stator and rotor, creating a buffer zone that accommodates thermal expansion and manufacturing tolerances while maintaining efficient power transmission
2Reliability
If the distance between stator and rotor is increased to avoid accidental contact, then reliability is improved, but power transfer capability deteriorates
Solution Approach 1:
The patent uses dynamically adjustable spacing mechanisms that allow the distance between stator and rotor to be optimized in real-time based on operating conditions, maintaining reliable gaps during normal operation while enabling closer positioning when safety conditions permit for improved power transfer
Solution Approach 2:
The patent changes the operating parameters of the air-coupled transformer, specifically optimizing the frequency and amplitude of the acoustic field to achieve efficient power transmission across larger gaps, thereby maintaining power transfer capability while ensuring safety margins
3Measurement precision
If external measuring devices are installed on the stator to monitor distance, then measurement precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent integrates the laser measuring device into the existing control unit of the machine tool, allowing the control unit to serve multiple functions including both process control and distance measurement, thereby avoiding additional space requirements and reducing overall system complexity
Solution Approach 2:
The patent combines the distance measurement function with the existing control and monitoring systems of the machine tool, merging multiple functions into unified hardware and software modules to minimize additional space and complexity while maintaining high measurement precision
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
Enables precise monitoring and measurement of the distance between stationary and movable parts, ensuring safe operation and efficient power transfer while minimizing costs and space requirements, and providing a flexible diagnostic function.
Implementation Method 1
The power transmission system comprises an air-coupled transformer which has the primary coil arranged in an element (stator) integral with a stationary part of the machine, and the secondary coil arranged in an element (rotor) integral with a movable part of the machine
Implementation Method 2
A contactless power transmission method and electrical power supply circuit that utilize an air-coupled transformer with a series resonant circuit and a controller to adjust the frequency of the primary electrical voltage, allowing for accurate measurement of the distance between the stator and rotor by maintaining resonance conditions
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Method for contactless power transmission between a stationary part (14) and a movable part (15) and electrical power supply circuit (17) for implementing the method comprising an air-coupled transformer (19) provided with a primary resonant circuit with a primary coil (20) supported by the stationary part and a secondary resonant circuit with a secondary coil (21) facing the primary resonant circuit and supported by the movable part. The primary resonant circuit is fed with an alternating primary electrical voltage (V1) which causes a primary electrical current (I1) to circulate. The primary electrical current (I1) induces in turn in the secondary resonant circuit an alternating secondary electrical voltage (V2) which causes a secondary electrical current (I2) to circulate. An electrical variable influencing the achievement of the resonance condition is adjusted, for example the frequency (F) of the primary electrical voltage, in such a way to operate in a resonance condition. The distance (d) between the stationary part and the movable part is determined as a function of a value of such electrical variable. A contactless connection system includes the stationary and movable parts and the electrical power supply circuit.