Switching Element Temperature Sensing via On-State Voltage Drop
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Solution Overview
Problem
Existing methods for determining the temperature of electronic switching elements are inaccurate as they measure external temperatures, which may differ significantly from internal temperatures, especially in cooled circuits, leading to potential damage from underestimation of actual internal temperatures.
Innovation Solution
A method using a temperature measuring circuit with two electronic switching elements and a voltage measuring unit, where one element is turned off and the other is turned on to measure the voltage drop and current intensity, allowing for precise determination of the internal temperature of the second element without external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermistor is installed in the vicinity of the electronic switching element to measure temperature, then the measurement device is simple and easy to implement, but the measurement precision is poor because it measures external temperature rather than internal temperature
Solution Approach 1:
The electronic switching element itself serves as the temperature sensor by utilizing its intrinsic on-resistance temperature dependence. The element measures its own internal temperature through voltage drop measurement during operation, eliminating the need for separate external thermistors and achieving accurate internal temperature measurement without additional measurement devices.
2Reliability
If the voltage measuring unit is coupled to the electronic module during operation with high voltage present, then continuous temperature monitoring is possible, but the voltage measuring unit may be damaged by excessively high voltage
Solution Approach 1:
The first electronic switching element is turned off before coupling the voltage measuring unit to the electronic module. This preliminary action decouples the high voltage from the measurement circuit, allowing safe voltage measurement. After measurement, the first switching element is turned back on to restore normal operation, enabling continuous monitoring without exposing the measuring unit to damaging voltages.
3Measurement precision
If the voltage measuring unit is coupled to the electronic module by turning off the first switching element, then precise voltage drop measurement is possible, but the circuit operation is interrupted
Solution Approach 1:
The temperature measurement is performed periodically by temporarily turning off the first electronic switching element, measuring the voltage drop across the second switching element, and then restoring normal operation. This periodic measurement approach allows accurate temperature monitoring while minimizing interruption to circuit productivity, as measurements are taken at discrete intervals rather than continuously blocking operation.
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 temperature determination of electronic switching elements during operation without interrupting the circuit, providing a more reliable measurement of the actual internal temperature, thus preventing damage from excessive heat.
Implementation Method 1
measuring a voltage drop across the second electronic switching element; determining the current intensity of a current flowing through the second electronic switching element; ascertaining the temperature of the second electronic switching element with the inclusion of the measured voltage drop and the determined current intensity
Implementation Method 2
switching losses and ohmic losses in respect of the electrical power occur during operation. These losses are converted into heat, as a result of which the temperature of the electronic switching elements rises
Data Source
AI summary
A method determines a temperature of at least one electronic switching element by way of a temperature measuring circuit. A first electronic switching element in an electronic module is first of all turned off and a second electronic switching element in the electronic module is turned on. A voltage measuring unit is then coupled to the electronic module and a voltage drop across the second electronic switching element is measured. A current intensity of a current flowing through the second electronic switching element is also determined and the temperature of the second electronic switching element is determined with the inclusion of the measured voltage drop and the determined current intensity. An electronic assembly for determining a temperature of at least one electronic switching element is also described.