Magnetostrictive Sensor Temperature Detection Circuit
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Solution Overview
Problem
Conventional magnetostrictive type sensors face challenges in accurately detecting temperature of the detecting coil while measuring applied stress, due to high costs and complex configurations associated with existing methods, such as using thermocouples or direct electric current signals.
Innovation Solution
A magnetostrictive type sensor temperature detecting circuit that utilizes an alternating electric current to detect temperature by measuring the time difference in current flow direction changes in response to square wave voltage polarity switches, allowing for temperature computation without additional sensors or complex circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermocouple sensor is provided to detect the temperature of the detecting coil, then the temperature detection accuracy is improved, but the cost increases and the sensor section becomes larger in size
Solution Approach 1:
The detecting coil itself is utilized to detect its own temperature by measuring its resistance value. The coil's inherent electrical property (resistance) changes with temperature, allowing the system to self-diagnose temperature without external sensors. This eliminates the need for additional thermocouple sensors and their associated circuitry, thereby reducing cost and complexity while maintaining detection accuracy.
Solution Approach 2:
The detecting coil serves dual functions: detecting applied stress through inductance changes and detecting temperature through resistance changes. By making the same component perform multiple measurement functions, the system eliminates the need for separate temperature sensing equipment, reducing overall device complexity and cost.
2Measurement precision
If a direct electric current signal is used to measure the resistance value of the detecting coil, then the temperature can be computed, but a separate direct electric current circuit is required which increases circuit complexity and makes measurement difficult when detecting applied stress
Solution Approach 1:
The temperature detection function is merged with the existing alternating current excitation circuit used for stress detection. The same circuit that applies AC voltage to detect stress via inductance changes is also used to measure resistance for temperature detection. This integration eliminates the need for a separate direct current circuit, reducing overall circuit complexity while enabling simultaneous stress and temperature measurements.
Solution Approach 2:
The excitation circuit is designed to perform multiple functions: applying voltage for stress detection and measuring current for temperature detection. By making the circuit universal, it can operate in different modes (AC excitation for stress, resistance measurement for temperature) without requiring separate dedicated circuits, thereby simplifying the overall system.
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 accurate and cost-effective temperature detection of the detecting coil during stress measurement, simplifying the circuit configuration and reducing costs, while maintaining high precision across a wide temperature range.
Implementation Method 1
a magnetostrictive member having a magnetostrictive property that changes the magnetic permeability thereof when acted on by an applied stress such as an applied rotary torque or an applied load
Implementation Method 2
the magnetostrictive type sensor is changed in the impedance of its detecting coil by changing in the temperature of the detecting coil
Implementation Method 3
uses a direct electric current signal, measures the resistance value of the detecting coil in the magnetostrictive type sensor, and computes the temperature of the detecting coil on the basis of the measured resistance value
Data Source
AI summary
A magnetostrictive-type sensor temperature-detecting circuit configured to be used in a magnetostrictive-type sensor including an applied stress-detecting coil, and a driving section to output an alternating voltage, excite the coil with a resulting alternating electric current, and switch flow directions of the electric current flowing in the coil in response to switching voltage polarities of the output alternating voltage, to detect a temperature of the coil in the sensor. This temperature-detecting circuit includes an alternating electric current direction switching time-detecting section to detect an amount of time from when the voltage polarities of the output alternating voltage are switched until when the flow directions of the electric current flowing in the coil are switched, and a temperature-computing section to compute the temperature of the coil on the basis of the amount of time detected by the alternating electric current direction switching time-detecting section.