Algorithm execution time and accuracy of NTC thermistor-based temperature measurements in time-critical applications

Petkovšek, Marko (author), Nemec, Mitja (author), Zajec, Peter (author)

This paper addresses the challenges of selecting a suitable method for negative temperature coefficient (NTC) thermistor-based temperature measurement in electronic devices. Although measurement accuracy is of great importance, the temperature calculation time represents an even greater challenge since it is inherently constrained by the control algorithm executed in the microcontroller (MCU). Firstly, a simple signal conditioning circuit with the NTC thermistor is introduced, resulting in a temperature-dependent voltage U$_T$ being connected to the MCU’s analog input. Next, a simulation-based approximation of the actual temperature vs. voltage curve is derived, resulting in four temperature notations: for a look-up table principle, polynomial approximation, B equation and Steinhart–Hart equation. Within the simulation results, the expected temperature error of individual methods is calculated, whereas in the experimental part, performed on a DC/DC converter prototype, required prework and available MCU resources are evaluated. In terms of expected accuracy, the look-up table and the Steinhart–Hart equation offer superior results over the polynomial approximation and B equation, especially in the nominal temperature range of the NTC thermistor. However, in terms of required prework, the look-up table is inferior compared to the Steinhart–Hart equation, despite the latter having far more complex mathematical functions, affecting the overall MCU algorithm execution time significantly.

• Language: English
• Keywords: NTC thermistor, temperature measurement, microcontrollers, control algorithm, calculation time, power electronics
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 16 str.
• Numbering: Vol. 9, iss. 18, art. 2266
• PID: 20.500.12556/RUL-136350
• UDC: 621.38:681.586.69
• ISSN on article: 2227-7390
• DOI: 10.3390/math9182266
• COBISS.SI-ID: 77467651
• Publication date in RUL: 25.04.2022

Record is a part of a journal

• Title: Mathematics
• Shortened title: Mathematics
• Publisher: MDPI AG
• ISSN: 2227-7390
• COBISS.SI-ID: 523267865

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 15.09.2021

Secondary language

• Language: Slovenian
• Keywords: NTK termistor, merjenje temperature, mikrokrmilniki, regulacijski algoritem, čas izračuna, močnostna elektronika

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: L2-2619
• Name: Napredni elektronski napajalni modul za avtomobilski katalizator