Method for online estimation of IGBT element junction temperature

Abstract

The invention discloses a method for online estimation of IGBT element junction temperature. The method comprises the steps that S1, a finite volume model is constructed; S2, temperature field distribution and surface heat exchange coefficient distribution are calculated according to the finite volume model; S3, a finite element model is constructed, and the surface heat exchange coefficient distribution is mapped to the finite element model; S4, according to predetermined temperature prediction targets and temperature monitoring points, transient temperature field calculation is performed on all the temperature prediction targets in sequence, and a data curve of changes of temperature of the temperature prediction targets and temperature of the temperature monitoring points over time is obtained; S5, the data curve is fitted, and a transfer function between temperature rise values of the temperature monitoring points and temperature rise values of the temperature prediction targets is obtained; and S6, actual temperature values and environment temperature values of the temperature monitoring points are measured, the temperature rise values of the temperature prediction targets are calculated through the transfer function, and temperature values of the temperature prediction targets are obtained through calculation. The method has the advantages that the integrity of elements does not need to be damaged, prediction speed is high, and accuracy is high.

Description

technical field [0001] The invention relates to the field of IGBT temperature detection, in particular to a method for online estimation of the junction temperature of IGBT elements that can be used for IGBT converters in industries such as rail transit, wind power generation, and electric vehicles. Background technique [0002] IGBT (Insulated Gate Bipolar Transistor) combines the advantages of MOSFET and bipolar transistor, and occupies a dominant position in high-frequency and medium-power applications. It is currently the traction converter of rail vehicles and wind power converter , electric vehicle motor controller and other applications in the core components. The failure of IGBT components will lead to failures such as vehicle shutdown and fan off-grid, which will cause certain economic losses and adverse social impacts. Therefore, the reliability of IGBT components is particularly important. According to many studies and literatures, the failure of IGBT components ...

AI Technical Summary

Problems solved by technology

Disadvantages: contact measurement is required; susceptible to interference from packaging materials; long response time; additional measurement equipment is required; the package needs to be changed or the device is unpacked directly; the internal space layout of the module is limited

Disadvantages: Need to remove the plastic case and silicone gel to measure the chip temperature more accurately; the whole set of equipment is expensive

Disadvantages: the measurement of saturation voltage drop needs to be carried out under the condition of passing a very small current, and the measurement of the gate turn-on delay requires a sampling device with a sampling frequency of nanoseconds. When measuring the current change rate, adding a measurement transformer will increase the parasitic inductance of the IGBT component Parameters, when measuring the voltage change rate, adding the capacitance used for measurement will increase the stray capacitance parameters, etc., which will easily cause accidents during the measurement process, and it is difficult to achieve online measurement

Disadvantages: In addition to the IGBT chip, there are anti-parallel diode chips inside the IGBT component, and high-power components have half-bridge, full-bridge, three-phase bridge and other packaging forms. Each chip is connected to the component substrate, and there is thermal coupling between the chips. Installing multiple IGBT components on the same heat sink will also cause thermal coupling. The parameters of thermal coupling are difficult to obtain. To calculate the junction temperature, you need to know the chip loss and case temperature, and the calculated junction temperature is a virtual average junction temperature.

The working conditions of IGBT components often change during the working process. It is impossible to evaluate the safe application, life and reliability of IGBT components in a timely and accurate manner by relying solely on the junction temperature in a steady state to evaluate the stable operation of the converter.

In the existing online measurement or estimation method of IGBT element junction temperature, it is difficult to take into account the integrity of IGBT element and the accuracy of junction temperature at the same time

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