Method for measuring temperature through frequency modulation

Abstract

The invention discloses a method for measuring temperature through frequency modulation, which comprises a thermosensitive element, a frequency modulation circuit, an isolation circuit and a temperature monitoring system, and comprises the following steps of: placing the thermosensitive element at a measured element, detecting the temperature change of the measured element by the thermosensitive element, and converting a temperature signal into an electric signal; establishing a one-to-one correspondence relationship between the frequency of the pulse signal and the temperature signal; the thermosensitive element is connected to the frequency modulation circuit, and the frequency modulation circuit receives an electric signal of the thermosensitive element and converts the electric signal into a frequency-variable pulse signal. The beneficial effects are that interference, error and offset problems of a traditional analog conditioning circuit can be avoided; the influence and damage of bad factors such as strong voltage, strong electromagnetic interference, static electricity, lightning stroke, surge and the like of a detected object on the monitoring system can be solved; the monitoring system only needs to detect the frequency modulation pulse signal, and does not need to use AD sampling to detect the temperature.

Description

technical field [0001] The invention belongs to the technical field of temperature measurement of electronic components, and in particular relates to a method for temperature measurement through frequency modulation. Background technique [0002] In power electronic products, such as rectifiers, inverters, DC converters, etc., power electronic devices and magnetic components are essential. These devices constitute the main part of power electronic products, and are also the main part of the product's loss and heat during its operation. Therefore, in order to monitor the operating status of the product, it is necessary to measure the temperature of the power electronic devices, inductors, transformers, capacitors, MCU, internal environment, external environment, heat sink, etc. in the product for heat dissipation and temperature control of the product. Control, derating operation, alarm and temperature protection are required when necessary. [0003] The temperature measure...

AI Technical Summary

Problems solved by technology

[0004] 1. The temperature signal is converted into an analog electrical signal. The analog signal is easy to introduce interference, error and offset during transmission and processing, resulting in insufficient measurement accuracy.

[0005] 2. The AD sampling of the temperature signal needs to occupy the AD sampling resources of the MCU. AD sampling is a faster MCU peripheral resource, and the temperature change is generally relatively slow, and there are multiple temperature sampling points.

Using MCU's AD peripherals and signal conditioning circuit for temperature sampling will cause a certain waste of software and hardware resources

[0006] 3. When using the thermal sensor + signal conditioning circuit + AD sampling scheme for temperature measurement, the electrical isolation between the measured object and the control system is not realized

In this way, it is easy to introduce strong voltage, strong electromagnetic interference, static electricity, lightning strikes, etc. of the main power part, heat sink, and product shell into the control system through the temperature detection circuit, causing the control system to malfunction or even collapse.

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