CN-122016081-A - Online measurement method for temperature of silicon carbide-based transistor based on gate pulse

CN122016081ACN 122016081 ACN122016081 ACN 122016081ACN-122016081-A

Abstract

The invention provides a grid pulse-based on-line measurement method for the temperature of a silicon carbide-based transistor, which belongs to the field of power semiconductor devices and comprises the steps of obtaining a temperature calibration curve of measured grid voltage, drain-source current and temperature of the silicon carbide-based transistor to be measured, connecting the silicon carbide-based transistor to be measured into a working circuit, recording the working grid voltage, applying negative pulses to a grid electrode of the silicon carbide-based transistor to be measured in a normal working state through a grid driving module at the moment when the temperature needs to be measured, reducing the working grid voltage to the measured grid voltage, collecting the instantaneous drain-source current when the negative pulses are applied through a current collecting module combined with a capacitance voltage stabilizing module, and calculating the temperature of the silicon carbide-based transistor to be measured at the current moment according to the temperature calibration curve of the drain-source current and the temperature. The invention solves the problem that the prior art cannot actively and flexibly measure the online junction temperature at any working stage because the switching transient state or the specific working stage of the silicon carbide-based transistor is relied on.

Inventors

ZHANG YAMIN
ZOU XINYU
MENG XIANWEI
BAI JIAYU
ZHAO YUANRONG

Assignees

北京工业大学

Dates

Publication Date: 20260512
Application Date: 20260206

Claims (7)

1. The on-line measurement method of the temperature of the silicon carbide-based transistor based on the gate pulse is characterized by comprising the following steps: Acquiring a temperature calibration curve of measured gate voltage, drain-source current and temperature of a silicon carbide-based transistor to be measured; the silicon carbide-based transistor to be tested is connected into a working circuit, enters a normal working state, and records the working grid voltage; Applying negative pulse to the grid electrode of the silicon carbide-based transistor to be tested in a normal working state through the grid electrode driving module at the moment when the temperature needs to be measured, reducing the working grid electrode voltage to the measured grid electrode voltage, and collecting the instant drain-source current when the negative pulse is applied through the current collecting module in combination with the capacitance voltage stabilizing module; And calculating the temperature of the silicon carbide based transistor to be measured at the current moment based on the instantaneous drain-source current according to the temperature calibration curve of the drain-source current and the temperature.
2. The method for online measurement of temperature of silicon carbide based transistor based on gate pulse according to claim 1, wherein the step of obtaining a calibration curve of gate voltage and drain-source current with temperature comprises: acquiring a transfer characteristic curve of a silicon carbide-based transistor to be measured, determining a grid voltage corresponding to the maximum temperature coefficient of drain-source current of the silicon carbide-based transistor to be measured according to the transfer characteristic curve, and determining the grid voltage as a measurement grid voltage; Placing the silicon carbide-based transistor to be tested in a plurality of constant temperature environments with different temperatures; In each constant temperature environment, applying short pulses with the same amplitude as the measured gate voltage to the gate of the silicon carbide-based transistor to be measured, and measuring the source leakage current corresponding to each constant temperature environment through a current acquisition circuit; and fitting to obtain a temperature calibration curve of the temperature and the source leakage current according to the temperature of each constant temperature environment and the corresponding source leakage current.
3. The method for online measurement of temperature of a silicon carbide based transistor based on gate pulses of claim 1, wherein the gate drive module comprises an adder, a gate driver and an FPGA; The negative electrode input end of the adder is respectively connected with one end of a first resistor and one end of a second resistor, the other end of the first resistor is respectively connected with the output end of the adder and the grid electrode of the silicon carbide-based transistor to be tested, the positive electrode input end of the adder is respectively connected with one end of a third resistor and one end of a fourth resistor, the other end of the third resistor and the other end of the fourth resistor are respectively connected with a grid electrode driver, and the grid electrode driver is connected with the FPGA.
4. The method for online measurement of temperature of silicon carbide based transistor based on gate pulse as claimed in claim 3, wherein the gate driving module operates in the following manner: When the temperature needs to be measured, the FPGA controls the gate driver to output a first voltage signal and a second voltage signal, the first voltage signal is input to the adder through a third resistor, and the second voltage signal is input to the adder through a fourth resistor; The adder receives the first voltage signal and the second voltage signal and outputs an output voltage with the amplitude being the sum of the first voltage signal and the second voltage signal to the grid electrode of the silicon carbide-based transistor to be detected; The magnitude of the first voltage signal is equal to the measured gate voltage, and the sum of the magnitudes of the first voltage signal and the second voltage signal is equal to the working gate voltage.
5. The method for online measurement of temperature of a silicon carbide based transistor based on gate pulses of claim 1, wherein the capacitive voltage stabilizing module comprises a capacitor, a voltage follower and an electromagnetic relay; One end of the capacitor is connected with the input end of the electromagnetic relay, the other end of the capacitor is grounded, a first output end of the electromagnetic relay is respectively connected with a load in a working circuit, a drain electrode of a silicon carbide-based transistor to be tested and an anode input end of the voltage follower, and a second output end of the electromagnetic relay is respectively connected with an output end and a cathode input end of the voltage follower.
6. The method for online measurement of temperature of silicon carbide based transistor based on gate pulse as claimed in claim 5, wherein the workflow of the capacitive voltage stabilizing module comprises a non-temperature measurement charge following phase and a temperature measurement voltage stabilizing phase; in a non-temperature measurement charging following stage, the silicon carbide-based transistor to be measured is in a normal working state, a switch of the electromagnetic relay is closed, and a capacitor is connected with a load in a working circuit through a voltage follower to finish the precharge of the capacitor; In the temperature measurement and voltage stabilization stage, when the silicon carbide-based transistor to be measured needs to perform temperature measurement, a switch of the electromagnetic relay is disconnected, and a capacitor which is precharged to the load voltage is directly connected with a load in a working circuit, and the voltage of the load is kept stable.
7. The method for online measurement of temperature of silicon carbide based transistor based on gate pulse as claimed in claim 1, wherein the current acquisition module comprises a sampling resistor, an input buffer unit and a differential amplifying unit; The sampling resistor is connected in series in a current loop working circuit of the silicon carbide-based transistor to be tested and is used for converting a current signal flowing through the sampling resistor into a differential voltage signal; The input buffer unit comprises two voltage followers, and the input ends of the two voltage followers are respectively connected with two ends of the sampling resistor and used for collecting and buffering differential voltage signals; the differential amplifying circuit comprises an operational amplifier, wherein two input ends of the operational amplifier are respectively connected with the output ends of the two voltage followers and used for amplifying and outputting the buffered voltage signals.

Description

Online measurement method for temperature of silicon carbide-based transistor based on gate pulse Technical Field The invention belongs to the field of power semiconductor devices, and particularly relates to an online measurement method for the temperature of a silicon carbide-based transistor based on gate pulse. Background Silicon carbide (SiC for short) is a third generation semiconductor material, and compared with a traditional silicon-based power device, the silicon-based power device has the advantages of higher forbidden bandwidth, higher breakdown field strength, higher electron saturation mobility and higher thermal conductivity, so that the silicon-based carbide transistor has higher working temperature, smaller on-resistance, larger power density, smaller switching loss and the like. Therefore, silicon carbide-based transistors play an increasingly important role in the fields of power electronics, new energy, aerospace and the like. However, the high electric field resistance and low on-resistance of silicon carbide based transistors may result in greater power consumption when operated at high currents and voltages, resulting in increased internal device temperatures, leading to a series of reliability problems such as threshold voltage drift, gate oxide degradation, on-resistance degradation, etc. Therefore, it becomes critical to accurately and rapidly acquire the junction temperature of the SiC power device. The current temperature detection method can be roughly classified into a physical contact method, an optical method, a thermal network model method and an electrical temperature-sensitive parameter method. The method can be used for realizing transient temperature rise measurement in the switching-on or switching-off transient process of the power device, but cannot meet the temperature measurement requirement at any working stage at any time and cannot track the real-time fluctuation rule of junction temperature in the whole course, while the requirements of the reliability guarantee technologies such as on-line temperature measurement, working state real-time monitoring and the like in the field of semiconductor devices are increasingly urgent, and the requirements of the reliability guarantee technologies such as the on-line temperature measurement, the working state real-time monitoring and the like are difficult to meet in the prior art. Disclosure of Invention The invention provides an online measurement method for the temperature of a silicon carbide based transistor based on gate pulse, which solves the problem that the online junction temperature measurement cannot be actively and flexibly carried out in any working stage in the prior art due to the fact that the online measurement is carried out in a switching transient state or a specific working stage of the silicon carbide based transistor. In order to achieve the above purpose, the invention adopts the technical scheme that the method for measuring the temperature of the silicon carbide-based transistor on line based on the gate pulse comprises the following steps: Acquiring a temperature calibration curve of measured gate voltage, drain-source current and temperature of a silicon carbide-based transistor to be measured; the silicon carbide-based transistor to be tested is connected into a working circuit, enters a normal working state, and records the working grid voltage; Applying negative pulse to the grid electrode of the silicon carbide-based transistor to be tested in a normal working state through the grid electrode driving module at the moment when the temperature needs to be measured, reducing the working grid electrode voltage to the measured grid electrode voltage, and collecting the instant drain-source current when the negative pulse is applied through the current collecting module in combination with the capacitance voltage stabilizing module; And calculating the temperature of the silicon carbide based transistor to be measured at the current moment based on the instantaneous drain-source current according to the temperature calibration curve of the drain-source current and the temperature. The invention provides a grid pulse-based on-line temperature measurement method for a silicon carbide transistor, which is characterized in that a grid pulse-based on-line temperature measurement method is provided, a negative pulse with a preset amplitude is superimposed on a grid electrode of the silicon carbide transistor under normal operation, so that the grid voltage is instantaneously reduced to a preset measurement grid voltage, the temperature measurement at any moment under all working conditions is realized, a capacitor voltage stabilizing module is designed, and a cut-in circuit is used for absorbing current transient and stabilizing load voltage during the temperature measurement, so that the interference of the temperature measurement action on a main working circuit is relieved. The invention realizes th