CN104732006A - IGBT module steady state temperature calculating method - Google Patents

Abstract

The invention discloses an IGBT module steady state temperature calculating method. The IGBT module steady state temperature calculating method comprises the following steps that an IGBT module loss is calculated; an IGBT module thermal characteristic parameter is input; an IGBT module radiating system thermal way model is established, and the thermal way model comprises an IGBT module, thermal conducting contact materials and a radiator; the IGBT module temperature is confirmed. According to the IGBT module steady state temperature calculating method, an equivalent thermal way model generated by the end thermal conducting characteristic mathematical approximation method in the prior art is avoided, the steady state calculation accuracy is guaranteed, and meanwhile the distortion and the error which are caused by non-physical thermal resistance and thermal capacity are avoided; the defects that a field domain calculation model is huge in calculation workload and severe in time consumption are avoided, and the working efficiency of the system design based on the IGBT module is improved.

Description

A kind of steady temperature calculating method of IGBT module

Technical field

The present invention relates to a kind of steady temperature calculating method, be specifically related to a kind of steady temperature calculating method of IGBT module.

Background technology

Igbt (Insulated Gate Bipolar Transistor, IGBT) is a kind of turned off power electronic devices that can be turned on and off by control signal.IGBT has three terminals: gate terminal (G) and two load terminal emitters (E), collector (C).By applying suitable voltage between gate pole and emitter, IGBT can control the electric current in a direction, i.e. turn-on and turn-off.Because IGBT device cannot bear back-pressure, in commercial Application general between two face terminals of IGBT device fly-wheel diode in parallel, and the formation IGBT module that is packaged together.IGBT has the advantages that input impedance is high, driving power is little, control circuit is simple, speed is fast and frequency of operation is high, be called one of power electronic devices having application prospect most, obtain in fields such as industry dragging, track traffic, high voltage power transmission, intelligent appliance and Industry Control and apply more and more widely.

In practical application, IGBT module needs often to turn on and off, with control load electric current, simultaneously, under turn-on and turn-off condition, IGBT module also will bear on state current and off state current, these all can make IGBT module bear certain power attenuation, produce heat and cause the lifting of IGBT module chip temperature.In order to ensure security when IGBT module works, general needs can be shed with the heat of generation in ensureing IGBT module and running in time by configuration air-cooled radiator or water-filled radiator.Due to the complex internal structure of IGBT module, particularly high-voltage IGBT module proposes very high request to insulating property, therefore, the problem that when temperature characterisitic how obtaining IGBT module chip in operation is power electronic equipment design, emphasis is considered also is the problem solved not yet very well.At present, mainly through calculating the running temperature characteristic obtaining IGBT module.

The temperature computation method of IGBT module mainly contains two kinds, thermal impedance analytic approach and field domain analytic approach, and these methods pay close attention to temperature changing trend, requires that complicated and parameter not easily obtains to design conditions.Publish " for IGBT module junction temperature prediction heat-electric coupling model investigation " (Wu Yansong etc. for IGBT module junction temperature prediction heat-electric coupling model investigation. electrician's electric energy new technology, 33 volume 3 phases, 2014) typical thermal impedance analytic approach is described in.The method needs the heat propagation characteristic of thermal impedance network analog heat dissipation element, due to the method to the simulation of material thermal characteristics in essence still for port approximate model and non-physical model, and in model the connected mode of thermal capacitance parameter and numerical value larger on computational accuracy impact, the problem such as the highest stable state junction temperature for major concern in engineering easily produces bigger numerical concussion, and easily causes comparatively big error.Patent " a kind of method and apparatus obtaining transient temperature of power electronic device " (patent No. CN 102930096A) discloses the computing method typically obtaining IGBT module transient temperature based on field domain analytic approach, the method establishes finite element model and the finite volume model of IGBT module, obtain the inner detailed convection coefficient distribution of IGBT module and Temperature Distribution, in engineering practice, the method needs detailed dimensions and the physical parameter of IGBT module inner structure, user cannot obtain, and each amount of calculation is huge and consuming time longer simultaneously.

The temperature computation method of high-voltage IGBT module mainly contains two kinds, thermal impedance analytic approach and field domain analytic approach.There is following technology prejudice respectively in these methods:

(1) these methods pay close attention to temperature changing trend, require that complicated and parameter not easily obtains to design conditions;

(2) numerical value of thermal capacitance parameter and arrangement comparatively large on computational accuracy impact, easily produce error;

(3) model parameter obtains difficulty, and general user cannot obtain;

(4) model amount of calculation is huge, consuming time longer.

Therefore, need to provide a kind of chip steady temperature calculating method that can meet the requirement of high-voltage IGBT module engineer applied computational accuracy to promote the work efficiency of IGBT module engineer applied design.

Summary of the invention

For the deficiencies in the prior art, the invention provides a kind of steady temperature calculating method of IGBT module, described IGBT module is made up of igbt chip and diode chip for backlight unit, and the steady temperature calculating method of described IGBT module comprises the following steps: calculate IGBT module loss; Input IGBT module thermal characteristic parameter; Set up IGBT module cooling system thermal circuit model, described thermal circuit model comprises IGBT module, thermal conductive contact material and heating radiator; Determine IGBT module temperature.

Preferably, the loss of described calculating IGBT module, comprises and calculates the total losses of described igbt chip and the total losses of described diode chip for backlight unit.

Preferably, the computing formula of the total losses of described igbt chip is:

$P_{\mathrm{IGBT}}=\frac{1}{T_{\mathrm{IGBT}}}\underset{t_0}{\overset{t_0+T_{\mathrm{IGBT}}}{\∫}}(U_{\mathrm{IGBT}}\·I_{\mathrm{IGBT}})\mathrm{dt}+\frac{N_{\mathrm{IGBT}}\·E_{\mathrm{sw}.\mathrm{IGBT}}}{T_{\mathrm{IGBT}}}$ ①

Formula 1. in, P _iGBTfor the total losses of described igbt chip, T _iGBTfor the described igbt chip loss calculation time, U _iGBTfor voltage, the I of described igbt chip _iGBTfor the electric current of described igbt chip, N _iGBTfor the on-off times of described igbt chip within the loss calculation time, E _sw.IGBTfor described igbt chip single switching loss;

Wherein, T _iGBTunit be s; U _iGBTfor variations per hour, unit is V; I _iGBTfor variations per hour, unit is A; E _sw.IGBTunit be J; P _iGBTunit be W.

Preferably, the computing formula of the total losses of described diode chip for backlight unit is:

$P_{\mathrm{FWD}}=\frac{1}{T_{\mathrm{FWD}}}\underset{t_0}{\overset{t_0+T_{\mathrm{FWD}}}{\∫}}(U_{\mathrm{FWD}}\·I_{\mathrm{FWD}})\mathrm{dt}+\frac{N_{\mathrm{FWD}}\·E_{\mathrm{sw}.\mathrm{FWD}}}{T_{\mathrm{FWD}}}$ ②

Formula 2. in, P _fWDfor the total losses of described diode chip for backlight unit, T _fWDfor the described diode chip for backlight unit loss calculation time, U _fWDfor the voltage of diode chip for backlight unit, I _fWDfor the electric current of diode chip for backlight unit, N _fWDfor diode chip for backlight unit opens number of times, E within the loss calculation time _sw.FWDfor diode chip for backlight unit single switching loss;

Wherein, T _fWDunit be s; U _fWDfor variations per hour, unit is V; I _fWDfor variations per hour, unit is A; E _sw.FWDunit be J; P _fWDunit be W.

Preferably, described input IGBT module thermal characteristic parameter comprises the following steps: the knot-shell thermal resistance R inputting described igbt chip _{th (j-c) .IGBT}; Input the knot-shell thermal resistance R of described diode chip for backlight unit _{th (j-c) .FWD}; Input the thermal resistance R of described thermal conductive contact material _{th (TIM) .chip}; Input the thermal resistance R of described radiator heat-dissipation face to external environment _{th (h-a)}; Input external environment temperature;

Wherein, described R _{th (j-c) .IGBT}, described R _{th (j-c) .FWD}, described R _{th (TIM) .chip}with described R _{th (h-a)}unit be K/W, described external environment temperature unit is DEG C.

Preferably, described R _{th (j-c) .IGBT}with described R _{th (j-c) .FWD}value be 1E-4 ~ 1E-3K/W, described R _{th (TIM) .chip}value be 1E-3 ~ 1E-2K/W, described R _{th (h-a)}value be 1E-3 ~ 20E-3K/W.

Preferably, described IGBT module cooling system thermal circuit model of setting up comprises the following steps: connect topology based on element in IGBT module delivered heat path and determine IGBT module cooling system thermal circuit model structure; Using the value of the total losses of igbt chip and diode chip for backlight unit as current source, using the numerical value of environment temperature as voltage source; The corresponding resistance of element thermal resistance to be connected in thermal circuit model between current source and voltage source according to delivered heat path and element annexation.

Preferably, described delivered heat path be heat transfer heat to shell by described igbt chip or described diode chip for backlight unit, transferred heat to described thermal conductive contact material by shell, by described thermal conductive contact material heat transfer to described heating radiator, by described radiator heat transfer to external environment.

Preferably, according to delivered heat path and element annexation the corresponding resistance of element thermal resistance is connected in thermal circuit model and between current source and voltage source is: in described thermal circuit model, igbt chip corresponding current source forms branch road 1 with the knot-corresponding resistant series of shell thermal resistance of described igbt chip, in described thermal circuit model, diode chip for backlight unit corresponding current source forms branch road 2 with the knot-corresponding resistant series of shell thermal resistance of described diode chip for backlight unit, forms branch road 3 after described branch road 1 is in parallel with described branch road 2.One end ground connection of current source and voltage source, the resistance that the other end is determined with delivered heat path and element annexation is connected.

Preferably, describedly determine IGBT module temperature, comprise the following steps:

Carry out circuit to the IGBT module cooling system thermal circuit model set up to solve;

By igbt chip corresponding current source in thermal circuit model and between the knot-shell thermal resistance of igbt chip the voltage of common node correspond to the junction temperature of igbt chip, this voltage unit is V, and this junction temperature unit is DEG C;

By diode chip for backlight unit corresponding current source in thermal circuit model and between the knot-shell thermal resistance of diode chip for backlight unit the voltage of common node correspond to the junction temperature of diode chip for backlight unit, this voltage unit is V, and this junction temperature unit is DEG C;

The voltage of the common node of the knot of the knot of igbt chip in thermal circuit model-shell thermal resistance, diode chip for backlight unit-between shell thermal resistance and the thermal resistance of thermal conductive contact material is corresponded to the skin temperature of IGBT module, this voltage unit is V, and this skin temperature unit is DEG C;

By the thermal resistance of thermal conductive contact material in thermal circuit model and radiator heat-dissipation face to external environment thermal resistance between the voltage of common node correspond to the surface temperature of heating radiator, this voltage unit is V, and this surface temperature unit is DEG C.

Preferably, described IGBT module integrate emitter-base bandgap grading voltage breakdown as 3300V, dc collector electric current is 1200A.

With immediate prior art ratio, beneficial effect of the present invention is:

The present invention obtains the loss of all chips in IGBT module by calculating the on-state loss of igbt chip and diode chip for backlight unit in IGBT module, off-state loss and switching loss respectively, the connection topological sum physics thermal resistance of each element in IGBT module calorie spread path is utilized to establish the hot road computation model of IGBT module, by measuring the thermal resistance parameters obtained in model, the node voltage calculated value of thermal circuit model is utilized to obtain the stable state chip temperature of IGBT module; By using the physics thermal resistance measuring acquisition, element heat transfer characteristic is described, avoid the Equivalent heat path model that prior art is produced by port heat transfer characteristic mathematical approach method, the distortion avoiding non-physical thermal resistance and thermal capacitance to produce while ensureing stable state computational accuracy and error; By using IGBT thermal circuit model, avoiding the huge serious drawback consuming time of field domain computation model amount of calculation, improving the work efficiency of the system based on IGBT module.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.

Fig. 1 is high-voltage IGBT module schematic diagram provided by the invention;

Fig. 2 is the flow chart of steps of the steady temperature calculating method of IGBT module in the embodiment of the present invention;

Fig. 3 is the variation diagram of voltage within computing time of igbt chip in the embodiment of the present invention;

Fig. 4 is the variation diagram of electric current within computing time of igbt chip in the embodiment of the present invention;

Fig. 5 is the variation diagram of voltage within computing time of diode chip for backlight unit in the embodiment of the present invention;

Fig. 6 is the variation diagram of electric current within computing time of diode chip for backlight unit in the embodiment of the present invention;

Fig. 7 is the calorie spread path schematic diagram of IGBT module in the embodiment of the present invention;

Fig. 8 is IGBT module cooling system thermal circuit model figure in the embodiment of the present invention;

Description of reference numerals: C1-IGBT chip; C2-diode chip for backlight unit; B1-basic cell structure; 10-IGBT module; 20-thermal conductive contact material; 30-heating radiator; 40-external environment air.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.

In order to thoroughly understand the embodiment of the present invention, by following description, detailed structure is proposed.Obviously, the execution of the embodiment of the present invention is not limited to the specific details that those skilled in the art has the knack of.Preferred embodiment of the present invention is described in detail as follows, but except these are described in detail, the present invention can also have other embodiments.

The present invention obtains the loss of all chips in IGBT module by calculating the on-state loss of igbt chip and diode chip for backlight unit in IGBT module, off-state loss and switching loss respectively, the connection topological sum physics thermal resistance of each element in IGBT module calorie spread path is utilized to establish the hot road computation model of IGBT module, by measuring the thermal resistance parameters obtained in model, the node voltage calculated value of thermal circuit model is utilized to obtain the stable state chip temperature of IGBT module.

As shown in Figure 1, Fig. 1 is high-voltage IGBT module schematic diagram provided by the invention to a kind of typical high voltage IGBT module provided by the invention.IGBT module in Fig. 1 is made up of igbt chip and diode chip for backlight unit, specifically comprises four igbt chip C1 and two diode chip for backlight unit C2 and forms basic cell structure B1.Several basic cell structures B1 constitutes an IGBT module 10, with 6 basic cell structure B1 for the best.Wherein, IGBT module 10 integrate emitter-base bandgap grading voltage breakdown as 3300V, dc collector electric current is 1200A.

With reference to the flow chart of steps that Fig. 2, Fig. 2 are the steady temperature calculating method of IGBT module in the embodiment of the present invention.Specifically comprise the following steps:

First, calculate IGBT module loss, comprise the following steps:

1, the total losses of igbt chip are calculated, with igbt chip loss calculation time T _iGBT, igbt chip voltage U _iGBT, igbt chip electric current I _iGBT, the on-off times N of igbt chip within computing time _iGBTwith igbt chip single switching loss E _sw.IGBTfor calculating variable, 1. calculate the total losses P of igbt chip according to formula _iGBT.Wherein, T _iGBTunit be s; U _iGBTfor variations per hour, unit is V; I _iGBTfor variations per hour, unit is A; E _sw.IGBTunit be J; P _iGBTunit be W.

$P_{\mathrm{IGBT}}=\frac{1}{T_{\mathrm{IGBT}}}\underset{t_0}{\overset{t_0+T_{\mathrm{IGBT}}}{\∫}}(U_{\mathrm{IGBT}}\·I_{\mathrm{IGBT}})\mathrm{dt}+\frac{N_{\mathrm{IGBT}}\·E_{\mathrm{sw}.\mathrm{IGBT}}}{T_{\mathrm{IGBT}}}$ ①

2, the total losses of diode chip for backlight unit are calculated, with diode chip for backlight unit loss calculation time T _fWD, diode chip for backlight unit voltage U _fWD, diode chip for backlight unit electric current I _fWD, diode chip for backlight unit opens times N within computing time _fWDwith diode chip for backlight unit single switching loss E _sw.FWDfor calculating variable, 2. calculate the total losses P of diode chip for backlight unit according to formula _fWD.Wherein, T _fWDunit be s; U _fWDfor variations per hour, unit is V; I _fWDfor variations per hour, unit is A; E _sw.FWDunit be J; P _fWDunit be W.

$P_{\mathrm{FWD}}=\frac{1}{T_{\mathrm{FWD}}}\underset{t_0}{\overset{t_0+T_{\mathrm{FWD}}}{\∫}}(U_{\mathrm{FWD}}\·I_{\mathrm{FWD}})\mathrm{dt}+\frac{N_{\mathrm{FWD}}\·E_{\mathrm{sw}.\mathrm{FWD}}}{T_{\mathrm{FWD}}}$ ②

Then, input IGBT module thermal characteristic parameter, comprises the following steps

1, the knot-shell thermal resistance R of igbt chip is inputted _{th (j-c) .IGBT}, its unit is K/W.There is certain variation range in the knot-shell thermal resistance of general igbt chip, the knot-shell thermal resistance for specific igbt chip limitedly should select its maximal value, can ensure the security of result of calculation like this.This thermal resistance general obtains by experiment measuring, and its representative value is 1E-4 ~ 1E-3K/W.Thermal resistance measurement technology belongs to existing mature technology.

2, the knot-shell thermal resistance R of input diode chip _{th (j-c) .FWD}, its unit is K/W.There is certain variation range in the knot-shell thermal resistance of general diode chip for backlight unit, the knot-shell thermal resistance for particular diode chip should use its maximal value, can ensure the security of result of calculation like this.This thermal resistance general obtains by experiment measuring, and its representative value is 1E-4 ~ 1E-3K/W.

3, the thermal resistance R of thermal conductive contact material is inputted _{th (TIM) .chip}, its unit is K/W.The thermal resistance of thermal conductive contact material is closely related with its material behavior, press-loading process and chip unit area, and generally this thermal resistance obtains by experiment measuring, and its representative value is 1E-3 ~ 1E-2K/W.

4, the thermal resistance R of radiator heat-dissipation face to external environment is inputted _{th (h-a)}, its unit is K/W.This thermal resistance general obtains by experiment measuring, and its representative value is 1E-3 ~ 20E-3K/W.

5, input external environment temperature, its unit is DEG C.This temperature general measures acquisition by experiment.

Then, set up IGBT module cooling system thermal circuit model, comprise the following steps:

1, connect topology based on element in IGBT module delivered heat path and determine IGBT module cooling system thermal circuit model structure.The element that thermal circuit model is considered mainly comprises igbt chip, diode chip for backlight unit, thermal conductive contact material and heating radiator.Delivered heat path is mainly heat and transfers heat to shell by igbt chip (or diode chip for backlight unit), transfers heat to thermal conductive contact material by shell, by thermal conductive contact material heat transfer to heating radiator, by radiator heat transfer in environment.

2, using the numerical value of igbt chip and diode chip for backlight unit total losses as current source, using the numerical value of environment temperature as voltage source, the unit of current source is A, and the unit of voltage source is V.

3, be connected in thermal circuit model between current source and voltage source according to delivered heat path and element annexation by corresponding for element thermal resistance resistance, unit of resistance is Ω.In thermal circuit model, igbt chip corresponding current source forms branch road 1 with the knot-corresponding resistant series of shell thermal resistance of igbt chip, in thermal circuit model, diode chip for backlight unit corresponding current source forms branch road 2 with the knot-corresponding resistant series of shell thermal resistance of diode chip for backlight unit, and in thermal circuit model, branch road 1 is in parallel with branch road 2 forms branch road 3 afterwards.One end ground connection of current source and voltage source, the resistance that the other end is determined with delivered heat path and element annexation is connected.

Finally, determine IGBT module temperature, comprise the steps:

1, carry out circuit to the IGBT module cooling system thermal circuit model set up to solve, typical method for solving comprises analytical method and numerical method;

2, by igbt chip corresponding current source in thermal circuit model and between the knot-shell thermal resistance of igbt chip the voltage of common node correspond to the junction temperature of igbt chip, this voltage unit is V, and this junction temperature unit is DEG C;

3, by diode chip for backlight unit corresponding current source in thermal circuit model and between the knot-shell thermal resistance of diode chip for backlight unit the voltage of common node correspond to the junction temperature of diode chip for backlight unit, this voltage unit is V, and this junction temperature unit is DEG C;

4, the voltage of the common node of the knot of the knot of igbt chip in thermal circuit model-shell thermal resistance, diode chip for backlight unit-between shell thermal resistance and the thermal resistance of thermal conductive contact material is corresponded to the skin temperature of IGBT module, this voltage unit is V, and this skin temperature unit is DEG C;

5, by the thermal resistance of thermal conductive contact material in thermal circuit model and radiator heat-dissipation face to external environment thermal resistance between the voltage of common node correspond to the surface temperature of heating radiator, this voltage unit is V, and this surface temperature unit is DEG C.

With reference to Fig. 3-Fig. 6, Fig. 3 is that the voltage of igbt chip in the embodiment of the present invention is schemed over time; Fig. 4 is that the electric current of igbt chip in the embodiment of the present invention is schemed over time; Fig. 5 is that the voltage of diode chip for backlight unit in the embodiment of the present invention is schemed over time; Fig. 6 is that the electric current of diode chip for backlight unit in the embodiment of the present invention is schemed over time.

T computing time of igbt chip loss in the present embodiment _iGBTfor 0.1s, the voltage U of igbt chip _iGBTas shown in Figure 3, the electric current I of igbt chip _iGBTas shown in Figure 4, the on-off times N of igbt chip within computing time _iGBTbe 10, igbt chip single switching loss E _sw.IGBTfor 2.76mJ, 1. calculate the total losses P of igbt chip according to formula _iGBTfor 2088.07W.

T computing time of diode chip for backlight unit loss in the present embodiment _fWDfor 0.1s, the voltage U of diode chip for backlight unit _fWDas shown in Figure 5, the electric current I of diode chip for backlight unit _fWDas accompanying drawing 6, diode chip for backlight unit opens times N within computing time _fWDbe 6, diode chip for backlight unit single switching loss E _sw.FWDfor 1.2mJ, 2. calculate the total losses P of diode chip for backlight unit according to formula _fWDfor 93.58W.

By measuring the knot-shell thermal resistance R that can obtain igbt chip in the present embodiment _{th (j-c) .IGBT}, its representative value is 0.009K/W; By measuring the knot-shell thermal resistance R that can obtain diode chip for backlight unit in the present embodiment _{th (j-c) .FWD}, its representative value is 0.018K/W; By measuring the thermal resistance R that can obtain thermal conductive contact material in the present embodiment _{th (TIM) .chip}, its representative value is 0.012K/W; Radiator heat-dissipation face can be obtained in the present embodiment to the thermal resistance R of external environment by measuring _{th (h-a)}, its representative value is 0.01K/W; The present embodiment China and foreign countries environment temperature T is obtained by measuring ₀, its representative value is 30 DEG C.

In the present embodiment IGBT module calorie spread path in element to connect topology with reference to accompanying drawing 7, Fig. 7 be the calorie spread path schematic diagram of IGBT module in the embodiment of the present invention.Heat is produced by IGBT module 10, is propagated in external environment air 40 by thermal conductive contact material 20, heating radiator 30.

Fig. 8 is IGBT module cooling system thermal circuit model figure in the embodiment of the present invention.Current source I _iGBTthe total losses power of corresponding igbt chip, amplitude is 2088.07A; Current source I _fWDthe total losses power of corresponding diode chip for backlight unit, amplitude is 93.58A; Voltage source V ₀corresponding external environment temperature, amplitude is 30V; Resistance R _iGBTknot-shell the thermal resistance of corresponding igbt chip, amplitude is 0.009 Ω; Resistance R _fWDknot-shell the thermal resistance of corresponding diode chip for backlight unit, amplitude is 0.018 Ω; Resistance R _tIM.chipthe thermal resistance of corresponding thermal conductive contact material, amplitude is 0.012 Ω; Resistance R _h-acorresponding radiator heat-dissipation face is to the thermal resistance of external environment, and amplitude is 0.01 Ω.

In the present embodiment, current source I _iGBTwith resistance R _iGBTseries connection forms branch road 1; Current source I _fWDwith resistance R _fWDseries connection forms branch road 2; Branch road 3 is formed after branch road 1 is in parallel with branch road 2; Branch road 3 and resistance R _tIM.chip, resistance R _h-a, voltage source V ₀series connection; Respectively by current source I _iGBT, current source I _fWD, voltage source V ₀one end ground connection be not connected with resistance.

In the present embodiment, based on the one of circuit analysis analytical method, i.e. nodal analysis, model is solved, current source I can be obtained _iGBTwith resistance R _iGBTcommon-node voltage is 96.8V; Current source I _fWDwith resistance R _fWDcommon-node voltage is 79.7V; Resistance R _iGBTwith resistance R _tIM.chipcommon-node voltage is 78.0V; Resistance R _tIM.chipwith resistance R _h-acommon-node voltage is 51.8V.

In the present embodiment, the junction temperature of known igbt chip is 96.8 DEG C; The junction temperature of diode chip for backlight unit is 79.7 DEG C; The skin temperature of IGBT module is 78.0 DEG C; The surface temperature of heating radiator is 51.8 DEG C.

The present invention obtains the loss of all chips in IGBT module by calculating the on-state loss of igbt chip and diode chip for backlight unit in IGBT module, off-state loss and switching loss respectively, the connection topological sum physics thermal resistance of each element in IGBT module calorie spread path is utilized to establish the hot road computation model of IGBT module, by measuring the thermal resistance parameters obtained in model, the node voltage calculated value of thermal circuit model is utilized to obtain the stable state chip temperature of IGBT module; By using the physics thermal resistance measuring acquisition, element heat transfer characteristic is described, avoid the Equivalent heat path model that prior art is produced by port heat transfer characteristic mathematical approach method, the distortion avoiding non-physical thermal resistance and thermal capacitance to produce while ensureing stable state computational accuracy and error; By using IGBT thermal circuit model, avoiding the huge serious drawback consuming time of field domain computation model amount of calculation, improving the work efficiency of the system based on IGBT module.

Finally should be noted that: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit; although with reference to above-described embodiment to invention has been detailed description; those of ordinary skill in the field still can modify to the specific embodiment of the present invention or equivalent replacement; these do not depart from any amendment of spirit and scope of the invention or equivalent replacement, are all applying within the claims awaited the reply.

Claims (11)

1. the steady temperature calculating method of an IGBT module, described IGBT module is made up of igbt chip and diode chip for backlight unit, it is characterized in that, the steady temperature calculating method of described IGBT module comprises the following steps:

Calculate IGBT module loss;

Input IGBT module thermal characteristic parameter;

Set up IGBT module cooling system thermal circuit model, described thermal circuit model comprises IGBT module, thermal conductive contact material and heating radiator;

Determine IGBT module temperature.

2. the steady temperature calculating method of IGBT module according to claim 1, is characterized in that, the loss of described calculating IGBT module, comprises and calculates the total losses of described igbt chip and the total losses of described diode chip for backlight unit.

3. the steady temperature calculating method of IGBT module according to claim 2, is characterized in that, the computing formula of the total losses of described igbt chip is:

$P_{\mathrm{IGBT}}=\frac{1}{T_{\mathrm{IGBT}}}\underset{t_0}{\overset{t_0+T_{\mathrm{IGBT}}}{\∫}}(U_{\mathrm{IGBT}}\·I_{\mathrm{IGBT}})\mathrm{dt}+\frac{N_{\mathrm{IGBT}}\·E_{\mathrm{sw}.\mathrm{IGBT}}}{T_{\mathrm{IGBT}}}$ ①

Formula 1. in, P _iGBTfor the total losses of described igbt chip, T _iGBTfor the described igbt chip loss calculation time, U _iGBTfor voltage, the I of described igbt chip _iGBTfor the electric current of described igbt chip, N _iGBTfor the on-off times of described igbt chip within the loss calculation time, E _sw.IGBTfor described igbt chip single switching loss;

Wherein, T _iGBTunit be s; U _iGBTfor variations per hour, unit is V; I _iGBTfor variations per hour, unit is A; E _sw.IGBTunit be J; P _iGBTunit be W.

4. the steady temperature calculating method of IGBT module according to claim 2, is characterized in that, the computing formula of the total losses of described diode chip for backlight unit is:

$P_{\mathrm{FWD}}=\frac{1}{T_{\mathrm{FWD}}}\underset{t_0}{\overset{t_0+T_{\mathrm{FWD}}}{\∫}}(U_{\mathrm{FWD}}\·I_{\mathrm{FWD}})\mathrm{dt}+\frac{N_{\mathrm{FWD}}\·E_{\mathrm{sw}.\mathrm{FWD}}}{T_{\mathrm{FWD}}}$ ②

Formula 2. in, P _fWDfor the total losses of described diode chip for backlight unit, T _fWDfor the described diode chip for backlight unit loss calculation time, U _fWDfor the voltage of diode chip for backlight unit, I _fWDfor the electric current of diode chip for backlight unit, N _fWDfor diode chip for backlight unit opens number of times, E within the loss calculation time _sw.FWDfor diode chip for backlight unit single switching loss;

Wherein, T _fWDunit be s; U _fWDfor variations per hour, unit is V; I _fWDfor variations per hour, unit is A; E _sw.FWDunit be J; P _fWDunit be W.

5. the steady temperature calculating method of IGBT module according to claim 1, is characterized in that, described input IGBT module thermal characteristic parameter comprises the following steps: the knot-shell thermal resistance R inputting described igbt chip _{th (j-c) .IGBT}; Input the knot-shell thermal resistance R of described diode chip for backlight unit _{th (j-c) .FWD}; Input the thermal resistance R of described thermal conductive contact material _{th (TIM) .chip}; Input the thermal resistance R of described radiator heat-dissipation face to external environment _{th (h-a)}; Input external environment temperature;

Wherein, described R _{th (j-c) .IGBT}, described R _{th (j-c) .FWD}, described R _{th (TIM) .chip}with described R _{th (h-a)}unit be K/W, described external environment temperature unit is DEG C.

6. the steady temperature calculating method of IGBT module according to claim 5, is characterized in that, described R _{th (j-c) .IGBT}with described R _{th (j-c) .FWD}value be 1E-4 ~ 1E-3K/W, described R _{th (TIM) .chip}value be 1E-3 ~ 1E-2K/W, described R _{th (h-a)}value be 1E-3 ~ 20E-3K/W.

7. the steady temperature calculating method of IGBT module according to claim 1, it is characterized in that, described IGBT module cooling system thermal circuit model of setting up comprises the following steps: connect topology based on element in IGBT module delivered heat path and determine IGBT module cooling system thermal circuit model structure; Using the numerical value of the total losses of igbt chip and diode chip for backlight unit as current source, using the numerical value of environment temperature as voltage source; The corresponding resistance of element thermal resistance to be connected in thermal circuit model between current source and voltage source according to delivered heat path and element annexation.

8. the steady temperature calculating method of IGBT module according to claim 7, it is characterized in that, described delivered heat path be heat transfer heat to shell by described igbt chip or described diode chip for backlight unit, transferred heat to described thermal conductive contact material by shell, by described thermal conductive contact material heat transfer to described heating radiator, by described radiator heat transfer to external environment.

9. the steady temperature calculating method of IGBT module according to claim 7, it is characterized in that, according to delivered heat path and element annexation the corresponding resistance of element thermal resistance is connected in thermal circuit model and between current source and voltage source is: in described thermal circuit model, igbt chip corresponding current source forms branch road 1 with the knot-corresponding resistant series of shell thermal resistance of described igbt chip, in described thermal circuit model, diode chip for backlight unit corresponding current source forms branch road 2 with the knot-corresponding resistant series of shell thermal resistance of described diode chip for backlight unit, branch road 3 is formed after described branch road 1 is in parallel with described branch road 2.One end ground connection of current source and voltage source, the resistance that the other end is determined with delivered heat path and element annexation is connected.

10. the steady temperature calculating method of IGBT module according to claim 1, is characterized in that, describedly determines IGBT module temperature, comprises the following steps:

Carry out circuit to the IGBT module cooling system thermal circuit model set up to solve;

By igbt chip corresponding current source in thermal circuit model and between the knot-shell thermal resistance of igbt chip the voltage of common node correspond to the junction temperature of igbt chip, this voltage unit is V, and this junction temperature unit is DEG C;

By diode chip for backlight unit corresponding current source in thermal circuit model and between the knot-shell thermal resistance of diode chip for backlight unit the voltage of common node correspond to the junction temperature of diode chip for backlight unit, this voltage unit is V, and this junction temperature unit is DEG C;

The voltage of the common node of the knot of the knot of igbt chip in thermal circuit model-shell thermal resistance, diode chip for backlight unit-between shell thermal resistance and the thermal resistance of thermal conductive contact material is corresponded to the skin temperature of IGBT module, this voltage unit is V, and this skin temperature unit is DEG C;

By the thermal resistance of thermal conductive contact material in thermal circuit model and radiator heat-dissipation face to external environment thermal resistance between the voltage of common node correspond to the surface temperature of heating radiator, this voltage unit is V, and this surface temperature unit is DEG C.

The steady temperature calculating method of 11. IGBT module according to the claim of claim 1-10 any one, is characterized in that, described IGBT module integrate emitter-base bandgap grading voltage breakdown as 3300V, dc collector electric current is 1200A.