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CN-121978497-A - Junction temperature detection method and device for IGBT module

CN121978497ACN 121978497 ACN121978497 ACN 121978497ACN-121978497-A

Abstract

The invention relates to the technical field of IGBT modules, and discloses a junction temperature detection method and device for an IGBT module. The method comprises the steps of S1, outputting a PWM driving signal to a grid electrode of an IGBT wafer through a singlechip to enable the IGBT wafer to conduct, S2, conducting heat conduction sensing on the NTC wafer, connecting the NTC wafer to a T pole pin through the NTC wafer and generating a T pole voltage signal with a pull-down resistor, S3, conducting AD conversion to obtain a T pole voltage digital quantity, calculating an NTC resistance value of the NTC wafer according to the T pole voltage digital quantity and searching a preset temperature data table to obtain a current junction temperature value of the IGBT wafer, S4, switching off the PWM driving signal when the current junction temperature value is larger than or equal to a preset protection threshold value, and continuously outputting the PWM driving signal and circularly executing steps S2 to S4 when the current junction temperature value is smaller than the preset protection threshold value. The invention can effectively protect the IGBT module from working in a reasonable temperature range, and improve the working reliability and service life of the IGBT module.

Inventors

  • WANG BIN
  • WANG CHAOGANG
  • ZHOU SHAOGUO

Assignees

  • 深圳市国王科技有限公司

Dates

Publication Date
20260505
Application Date
20260331

Claims (10)

  1. 1. The junction temperature detection method of the IGBT module is characterized by comprising the following steps of: S1, outputting PWM driving signals to the grid electrode of an IGBT wafer through a singlechip to enable the IGBT wafer to conduct work; S2, conducting heat conduction sensing on an NTC wafer which is sealed in the same package with the IGBT wafer, and generating a T-pole voltage signal through a voltage dividing circuit which is formed by connecting the NTC wafer to a T-pole pin and a pull-down resistor; S3, carrying out AD conversion on the T-pole voltage signal to obtain a T-pole voltage digital quantity, calculating an NTC resistance value of the NTC wafer according to the T-pole voltage digital quantity, and searching a preset temperature data table to obtain a current junction temperature value of the IGBT wafer; and S4, comparing the current junction temperature value with a preset protection threshold value, turning off the PWM driving signal when the current junction temperature value is larger than or equal to the preset protection threshold value, continuously outputting the PWM driving signal when the current junction temperature value is smaller than the preset protection threshold value, and circularly executing the steps S2 to S4.
  2. 2. The method of detecting a junction temperature of an IGBT module according to claim 1, wherein step S1 includes: s11, configuring PWM driving signals by the singlechip and transmitting the PWM driving signals to the grid electrode of the IGBT wafer through the driving resistor; and S12, when the PWM driving signal is at a high level, the IGBT wafer is conducted to form a load current loop and generate power loss heat.
  3. 3. The method of detecting a junction temperature of an IGBT module according to claim 1, wherein step S2 includes: S21, sensing power loss heat generated by the IGBT wafer through an NTC wafer which is sealed in the same package with the IGBT wafer; S22, connecting one end of the NTC wafer to the T-pole pin through a binding wire, and simultaneously connecting the other end of the NTC wafer to an emitter to form a voltage dividing circuit with the pull-down resistor; S23, generating a T-pole voltage signal reflecting the change of the NTC resistance value on the T-pole pin based on the voltage dividing circuit.
  4. 4. The method for detecting the junction temperature of the IGBT module according to claim 3, wherein step S23 includes: S231, applying a stabilized voltage power supply to a voltage division loop formed by the NTC wafer and the pull-down resistor; s232, obtaining corresponding divided voltage at the T-pole pin based on the NTC resistance value change of the NTC wafer in the divided voltage loop; And S233, filtering the divided voltage of the T pole pin through a filter capacitor to obtain a T pole voltage signal.
  5. 5. The method of detecting a junction temperature of an IGBT module according to claim 1, wherein step S3 includes: s31, an AD converter of the singlechip carries out analog-to-digital conversion on the T-pole voltage signal to obtain a T-pole voltage digital quantity; S32, calculating an NTC resistance value of the NTC wafer according to the digital T-pole voltage quantity, the voltage value of the stabilized power supply and the resistance value of the pull-down resistor; and S33, searching a preset temperature data table according to the NTC resistance value to obtain the current junction temperature value of the IGBT wafer.
  6. 6. The method of detecting a junction temperature of an IGBT module according to claim 5, wherein step S31 includes: S311, triggering an AD converter by a singlechip to select an analog input channel connected with a T pole and start a sampling hold circuit, and charging and sampling the T pole voltage signal by a sampling capacitor of the sampling hold circuit to obtain a hold voltage value; And S312, the AD converter quantizes the holding voltage value and stores the quantized holding voltage value into a data register to obtain a T-pole voltage digital quantity.
  7. 7. The method of detecting a junction temperature of an IGBT module according to claim 6, wherein step S32 includes: s321, multiplying the T-pole voltage digital quantity by a quantized stepping value to obtain an actual voltage value of a T-pole pin; S322, subtracting the actual voltage value from the voltage value of the stabilized power supply to obtain a divided voltage value on the NTC wafer; S323, multiplying the resistance value of the pull-down resistor by the ratio of the divided voltage value on the NTC wafer to the actual voltage value to obtain the NTC resistance value of the NTC wafer.
  8. 8. The method of detecting a junction temperature of an IGBT module according to claim 1, wherein step S4 includes: s41, the singlechip reads a preset protection threshold value and compares the preset protection threshold value with the current junction temperature value; S42, when the current junction temperature value is greater than or equal to a preset protection threshold value, the singlechip forcibly pulls down the PWM output pin to 0V to turn off the PWM driving signal; and S43, when the current junction temperature value is smaller than a preset protection threshold value, the singlechip maintains the output of the PWM driving signal and returns to execute the steps S2 to S4.
  9. 9. The method of detecting a junction temperature of an IGBT module according to claim 8, wherein step S42 includes: S421, the singlechip forcibly pulls the level of a PWM output pin connected to the driving resistor down to 0V, and stops outputting the PWM driving signal; And S422, the driving resistor stops transmitting driving current to the grid electrode of the IGBT wafer, the grid electrode voltage is discharged to 0V through a pull-down path, the IGBT wafer is switched from an on state to an off state, and a load current loop is cut off.
  10. 10. The junction temperature detection device of the IGBT module is characterized by comprising an IGBT module, a sampling circuit, a filter circuit, a singlechip and a power supply circuit, wherein the IGBT module is used for sealing an NTC wafer and an IGBT wafer, the NTC signal end of the IGBT module is electrically connected with the sampling circuit, the sampling circuit is electrically connected with the filter circuit, the filter circuit is connected with the singlechip, and the power supply circuit is used for providing a working power supply.

Description

Junction temperature detection method and device for IGBT module Technical Field The invention relates to the technical field of IGBT modules, in particular to a junction temperature detection method and device of an IGBT module. Background The temperature rise of the power device relates to the use safety and service life of the power device, and the power device is a core device for realizing functions and service life of a finished product. With the rapid development of economy, more and more people use electronic products with more power devices, such as air conditioners, microwave ovens, electromagnetic ovens, IH electric cookers, and the like. The power devices are used in the products and must be ensured to operate in a proper temperature range. Over-temperature of the power device easily causes device damage or direct damage. The existing power device is required to be attached to a power device plastic package shell for detecting temperature, a finished product NTC is required to be installed, the IGBT junction temperature is required to be conducted to the shell of the NTC finished product through plastic package materials and then conducted to an NTC wafer from the NTC shell, the internal resistance of the NTC wafer is changed due to temperature change, and the NTC internal resistance change is transmitted to a sampling, filtering and single chip microcomputer for processing through a lead. The scheme can not directly sample the IGBT junction temperature and can not accurately sample the IGBT junction temperature in time. Meanwhile, the method is influenced by an installation process, the contact area of the NTC and the IGBT shell, the IGBT plastic packaging quality, the IGBT plastic packaging material and the like. More IGBT junction temperature spaces are usually required to be compensated and reserved, so that the working reliability and service life of the IGBT in a batch product can be guaranteed. Meanwhile, the overall cost is high, the production process is complex, and the production efficiency of finished products is affected. The conventional method for detecting junction temperature of the power device is to attach and install an NTC finished product outside the package of the IGBT to sample the temperature of the package shell of the IGBT, and then estimate the junction temperature of the IGBT through a sample actual test. Because the temperature of the plastic package shell of the finished product of the IGBT is detected by the finished product NTC, the junction temperature of the IGBT cannot be accurately detected in real time, so that the IGBT has to reserve enough temperature margin in batch application. At this time, the IGBT generally cannot fully utilize the performance, resulting in resource waste. Disclosure of Invention The invention mainly aims to provide a junction temperature detection method and device for an IGBT module, which can effectively protect the IGBT module from working in a reasonable temperature range, and improve the working reliability and service life of the IGBT module. In order to achieve the above object, the present invention provides a junction temperature detection method for an IGBT module, comprising the steps of: S1, outputting PWM driving signals to the grid electrode of an IGBT wafer through a singlechip to enable the IGBT wafer to conduct work; S2, conducting heat conduction sensing on an NTC wafer which is sealed in the same package with the IGBT wafer, and generating a T-pole voltage signal through a voltage dividing circuit which is formed by connecting the NTC wafer to a T-pole pin and a pull-down resistor; S3, carrying out AD conversion on the T-pole voltage signal to obtain a T-pole voltage digital quantity, calculating an NTC resistance value of the NTC wafer according to the T-pole voltage digital quantity, and searching a preset temperature data table to obtain a current junction temperature value of the IGBT wafer; and S4, comparing the current junction temperature value with a preset protection threshold value, turning off the PWM driving signal when the current junction temperature value is larger than or equal to the preset protection threshold value, continuously outputting the PWM driving signal when the current junction temperature value is smaller than the preset protection threshold value, and circularly executing the steps S2 to S4. Optionally, in a first implementation manner of the first aspect of the present invention, step S1 includes: s11, configuring PWM driving signals by the singlechip and transmitting the PWM driving signals to the grid electrode of the IGBT wafer through the driving resistor; and S12, when the PWM driving signal is at a high level, the IGBT wafer is conducted to form a load current loop and generate power loss heat. Optionally, in a second implementation manner of the first aspect of the present invention, step S2 includes: S21, sensing power loss heat generated by the IGBT wafer through an NTC wafe