Three-Wire Transformer Position Sensor with Temperature Compensation
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Solution Overview
Problem
Current transformer position sensors, particularly those used in harsh aircraft environments, require simplification and cost reduction while maintaining reliability, as they often use five wires to detect two-position valve positions.
Innovation Solution
A three-wire transformer position sensor design is introduced, featuring an excitation coil, an output coil, and a movable magnetically permeable core, with a constant current circuit and filter circuit for temperature compensation, using a processor to generate a stair-step sinusoidal excitation voltage and process output signals for position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a five-wire transformer position sensor is used to detect valve position in harsh aircraft environments, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the excitation coil and output coil into a single integrated transformer assembly with shared magnetic core, eliminating the need for separate wiring harnesses and external circuitry. The three-wire configuration merges multiple functions into fewer connections, reducing overall system complexity while maintaining the reliable transformer sensing principle in harsh aircraft environments
2Measurement precision
If a five-wire transformer position sensor is used for position detection, then measurement precision is improved, but weight increases
Solution Approach 1:
The integration of excitation and output coils with shared magnetic core reduces the overall sensor weight by eliminating redundant components. The three-wire configuration consolidates multiple circuit functions into a single lightweight package, maintaining precise position sensing capability while reducing the weight burden on the aircraft system
Solution Approach 2:
The patent employs differential winding configuration in the output coil where adjacent turns are wound in opposite directions, creating local magnetic field cancellation that enhances position sensing precision. This localized quality improvement in the coil structure achieves better measurement accuracy without proportionally increasing overall sensor weight
3Measurement precision
If differential wound coils are used in variable differential transformer position sensors, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the differential winding configuration directly into the output coil structure itself, rather than requiring separate differential coils and external differential amplification circuitry. This integration maintains the precision benefits of differential sensing while reducing overall device complexity by eliminating additional components and wiring
Solution Approach 2:
The output coil's differential winding configuration inherently provides differential signal output that can be directly processed by simple summing circuitry. The coil structure itself performs the differential measurement function, making the system self-sufficient and reducing the need for complex external signal processing equipment
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
The three-wire design provides reliable two-position sensing at lower cost and weight, with improved temperature compensation, enabling robust operation over a broad temperature range and in harsh environments.
Implementation Method 1
The output coil is inductively coupled to the excitation coil and is configured, when it is balanced and the excitation coil is being electrically excited, to supply a null output signal
Implementation Method 2
The core is disposed adjacent, and movable relative to, the excitation coil and the output coil, and is operable, upon movement thereof, to vary the inductive coupling between the excitation coil and the output coil
Data Source
AI summary
A three-wire transformer position sensor is provided that includes an excitation coil and an output coil. The excitation coil is adapted to be electrically excited with an excitation signal, and has a first end and a second end. The output coil includes a first coil and a second coil and is inductively coupled to the excitation coil upon electrical excitation thereof the excitation coil. The first end of the first coil is electrically connected to the second end of the second coil and to the second end of the excitation coil, and the second end of the first coil is electrically connected to the first end of the second coil. The output coil is configured, when it is balanced and the excitation coil is being electrically excited, to supply a null output signal.