Temperature Sensor Thermal Loss Compensation via Periodic Current Control
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Solution Overview
Problem
Existing temperature sensors face inaccuracies in temperature estimation due to thermal losses, which are not adequately accounted for in measurement processes.
Innovation Solution
A temperature sensor system that includes a thermistor, a temperature measurement module, a command module, a thermal loss determination module, and a temperature estimation module. This system modifies the electrical circuit behavior to change the current flowing through the thermistor, thereby accounting for thermal losses and improving temperature estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the thermistor current is increased to improve measurement speed, then the measurement response is faster, but the thermal loss increases causing measurement inaccuracy
Solution Approach 1:
The patent applies periodic action by using a command module to periodically switch the electrical circuit between different operational modes. The circuit alternates between a first mode (with higher current for faster response) and a second mode (with lower current for accurate measurement), allowing the system to benefit from both high speed and high precision at different times in a periodic cycle.
Solution Approach 2:
The patent implements preliminary action through the thermal loss determination module, which calculates and compensates for thermal losses before they significantly affect the measurement. By determining thermal loss based on the command history and thermistor characteristics, the system proactively corrects for heating effects rather than reacting to them after they occur.
2Measurement precision
If the thermistor current is decreased to reduce thermal loss, then measurement accuracy improves, but the measurement response becomes slower
Solution Approach 1:
The system uses periodic switching between measurement modes, alternating between low-current accurate measurement phases and high-current rapid response phases. This allows the thermistor to be measured with minimal self-heating while still maintaining the capability for fast temperature tracking when needed.
Solution Approach 2:
The patent employs feedback through the thermal loss determination module that continuously monitors the command signal and thermistor temperature, calculating the thermal loss in real-time. This feedback loop allows the system to compensate for thermal effects dynamically, maintaining accuracy regardless of the current level used for measurement.
3Device complexity
If a simple measurement circuit is used, then device complexity is reduced, but thermal loss compensation capability is insufficient
Solution Approach 1:
The patent segments the measurement system into distinct functional modules: a temperature measurement module for basic thermistor measurement, a command module for circuit control, and a thermal loss determination module for compensation calculations. This segmentation allows each module to perform its specific function with appropriate complexity, while the overall system achieves high accuracy through their coordinated operation.
Solution Approach 2:
The command module serves as an intermediary between the simple temperature measurement circuit and the thermal loss compensation algorithm. It generates control signals that switch the circuit between different configurations and provides this control information to the thermal loss determination module, enabling complex compensation behavior through a relatively simple intermediate control layer.
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 system effectively reduces measurement inaccuracy caused by thermal losses by incorporating dynamic thermal models and thermal loss correction mechanisms, leading to a more accurate estimation of object temperatures.
Implementation Method 1
a temperature measurement module configured for determining a measured temperature of the thermistor from an electrical quantity of the electrical circuit that depends on a resistance of the thermistor
Implementation Method 2
the thermal loss of the thermistor is taken into account in the temperature estimation so that the measurement inaccuracy due to this thermal loss may be at least partially avoided
Data Source
AI summary
A temperature sensor (116) comprises an electrical circuit (204) including a thermistor (206) intended to be placed next to an object (112); a temperature measurement module (222) configured for determining a measured temperature (T_M) of the thermistor (206) from a resistance of the thermistor (206); and a command module (224) configured for providing a command (C) to the electrical circuit (204) for modifying the electrical circuit (204) in a way that changes a current (IT) flowing in the thermistor (206). The temperature sensor (116) further comprises a thermal loss determination module (226) configured for determining a thermal loss (L) of the thermistor (206) from the thermistor measured temperature (T_M) and the command (C); and a temperature estimation module (228) configured for estimating a temperature (T0_E) of the object (112) from the thermistor measured temperature (T_M) and from the thermal loss (L) of the thermistor (TH).