CN103701105A - Thermal overload protection method, device and system for power electronic equipment - Google Patents

Abstract

The invention provides a thermal overload protection method for power electronic equipment. The thermal overload protection method comprises the following steps of determining the loss of an insulated gate bipolar transistor (IGBT), the loss of a diode and the thermal impedence of the IGBT in the power electronic equipment to be detected and detecting the current temperature of a radiator, wherein the thermal impedence comprises thermal impedence between an IGBT junction and a shell and thermal impedence between the shell and the radiator; then calculating the junction temperature of the IGBT in the power electronic equipment to be detected according to a preset formula; finally judging whether the junction temperature is higher than the preset temperature, if so, stopping sending an IGBT driving signal to make the IGBT stop working. Therefore, the thermal impedence between the IGBT junction and the shell and the thermal impedence between the shell and the radiator are detected by the method; compared with a method for over-temperature protection of an IGBT module by detecting the temperature of the radiator in the prior art, the method has the advantages that a detection result is more accurate, an alarm is given during the over-temperature of the IGBT, and the burn of the IGBT module is avoided.

Description

A kind of thermal overload protection method of power electronic equipment, Apparatus and system

Technical field

The present invention relates to electric and electronic technical field, in particular, relate to a kind of thermal overload protection method, Apparatus and system of power electronic equipment.

Background technology

In power electronic equipment, IGBT module has become irreplaceable device for power switching, and the thermal effect producing is in the course of the work also inevitable.

At present, the overtemperature protection of IGBT module is mainly by thermistor, to gather the radiator temperature of IGBT module, and then realizes overtemperature protection according to this temperature.But inventor's discovery, because the thermal characteristics of different materials is different, and the thermal response speed of IGBT module, variations in temperature is large, and radiator is slow to the speed of thermal response, variations in temperature is little, and the temperature of radiator can not represent the real time temperature of IGBT module.

Can cause like this starting moment after power electronic equipment is shut down; radiator temperature is higher, output current is large, output frequency is lower; now IGBT module junction temperature fluctuation is large; the virtual junction temperature of IGBT module is overrate possibly; and radiator temperature be not equal to the instantaneous junction temperature of IGBT module now; make test result inaccurate, even can cause IBGT module burn or lost efficacy.

Summary of the invention

In view of this, the invention provides a kind of thermal overload protection method of power electronic equipment, to overcome the instantaneous junction temperature that represents IGBT in prior art by detecting radiator temperature, test result is inaccurate, the problem that causes IGBT module to be burnt.

For achieving the above object, the invention provides following technical scheme:

A thermal overload protection method for power electronic equipment, is applied to power electronic equipment, and described power electronic equipment comprises IGBT module, and IGBT and diode that described IGBT module comprises and connects, comprising:

Determine the consume P of IGBT in power electronic equipment to be detected _igbtconsume P with diode _diode;

Determine the thermal impedance Z of IGBT in described power electronic equipment to be detected _igbt, described thermal impedance comprises the thermal impedance Z between described IGBT knot and shell _jc-igbtand the thermal impedance Z between described shell and radiator _ch;

Detect the Current Temperatures T of described radiator _h;

According to the consume P of IGBT in described power electronic equipment to be detected _igbtconsume P with diode _diode, the thermal impedance Z of IGBT in described power electronic equipment to be detected _igbt, described radiator Current Temperatures T _h, according to default formula, calculate the junction temperature T of IGBT in described power electronic equipment to be detected _j-igbt;

Judge described junction temperature T _j-igbtwhether be greater than preset temperature, if so, stop sending the driving signal of IGBT, described IGBT quits work.

Preferably, calculate described IGBT junction temperature T _j-igbtdefault formula be: T _j-igbt=T _h+ (P _igbt+ P _diode) * Z _ch+ P _igbt* Z _jc-igbt.

Preferably, in described definite power electronic equipment to be detected, the consume of IGBT or diode comprises:

Calculate in the first Preset Time, the average loss of IGBT or diode in described power electronic equipment to be detected, described average loss comprises the switch consume of IGBT in the conducting consume of IGBT in described power electronic equipment to be detected or diode and described power electronic equipment to be detected or diode.

Preferably, in described power electronic equipment to be detected, the conducting of IGBT consume is:

wherein, V _ce0the fixed pressure drop of emitter and inter-collector during for the conducting of IGBT in power electronic equipment to be detected, _ipeakfor the maximum current of IGBT in described power electronic equipment to be detected, R _ce0for the impedance of emitter and the inter-collector when the conducting of IGBT in power electronic equipment to be detected, m is modulation ratio,

for power factor.

Preferably, in described power electronic equipment to be detected, the consume of the switch of IGBT is:

wherein, f _swfor the switching frequency of IGBT in power electronic equipment to be detected, E _onfor the loss producing during IGBT conducting in power electronic equipment to be detected, E _offthe loss producing while turn-offing for IGBT in power electronic equipment to be detected, I _nomfor measuring current, V _dcfor direct voltage, V _nomfor test voltage.

Preferably, in described definite power electronic equipment to be detected, the consume of IGBT or diode comprises:

Calculate IGBT or the real-time consume of diode in switch periods in described power electronic equipment to be detected, described real-time consume comprises the switch consume of IGBT in the conducting consume of IGBT in power electronic equipment to be detected or diode and power electronic equipment to be detected or diode.

Preferably, in described power electronic equipment to be detected, the conducting of IGBT consume is: P _cond.igbt=(V _ce0+r _ce0i) * i* τ; Wherein, V _ce0the fixed pressure drop of emitter and inter-collector during for the conducting of IGBT in power electronic equipment to be detected, R _ce0for the impedance of emitter and the inter-collector when the conducting of IGBT in power electronic equipment to be detected, τ is that shell is to the time constant of radiator test point thermal impedance.

Preferably, in described power electronic equipment to be detected, the consume of the switch of IGBT is:

wherein, f _swfor the switching frequency of IGBT in power electronic equipment to be detected, E _onfor the loss producing during IGBT conducting in power electronic equipment to be detected, E _offthe loss producing while turn-offing for IGBT in power electronic equipment to be detected, I _nomfor measuring current, V _dcfor direct voltage, V _nomfor test voltage.

A heat overload protector for power electronic equipment, comprising:

The first determination module, for determining the consume P of power electronic equipment IGBT to be detected _igbtconsume P with diode _diode;

The second determination module, for determining the thermal impedance of described power electronic equipment IGBT to be detected, described thermal impedance Z _igbtcomprise the thermal impedance Z between described IGBT knot and shell _jc-igbtand the thermal impedance Z between described shell and radiator _ch;

Detection module, for detection of the Current Temperatures T of described radiator _h;

Processing module, for according to the consume P of described power electronic equipment IGBT to be detected _igbtconsume P with diode _diode, the thermal impedance Z of IGBT in described power electronic equipment to be detected _igbt, described radiator Current Temperatures T _h, according to default formula, calculate the junction temperature T of IGBT in described power electronic equipment to be detected _j-igbt;

Judge module, for judging whether described junction temperature is greater than preset temperature, if so, stops sending the driving signal of IGBT, and described IGBT quits work.

A thermal overload protection system for power electronic equipment, comprises the heat overload protector of power electronic equipment and above-mentioned power electronic equipment.

Known via above-mentioned technical scheme; compared with prior art; the invention provides a kind of thermal overload protection method of power electronic equipment; by determining the thermal impedance of IGBT in the consume of IGBT in power electronic equipment to be detected, power electronic equipment to be detected and the Current Temperatures that detects radiator; wherein, thermal impedance comprises thermal impedance between described IGBT knot and shell and the thermal impedance between described shell and radiator.According to default formula, calculate the junction temperature of IGBT in described power electronic equipment to be detected afterwards.Finally, judge whether described junction temperature is greater than preset temperature, if so, stop sending the driving signal of IGBT, described IGBT quits work.Visible; the present invention has detected thermal impedance between thermal impedance between IGBT knot and shell and shell and radiator; in prior art, by detecting radiator temperature, do the overheat protector of IGBT module; testing result is more accurate; and then report to the police when IGBT excess temperature, avoided burning of IGBT module.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only embodiments of the invention, for those of ordinary skills, do not paying under the prerequisite of creative work, other accompanying drawing can also be provided according to the accompanying drawing providing.

Fig. 1 is the flow chart of the thermal overload protection method of a kind of power electronic equipment provided by the invention;

Fig. 2 is that a kind of IGBT shell provided by the invention is to the temperature rise curve of radiator;

Fig. 3 is the structural representation of the heat overload protector of a kind of power electronic equipment provided by the invention.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

Referring to accompanying drawing 1, is the flow chart of the thermal overload protection method of a kind of power electronic equipment provided by the invention, and the junction temperature of the method by detecting IGBT, to realize overload protection, comprises the steps:

S101: the consume P that determines IGBT in power electronic equipment to be detected _igbtconsume P with diode _diode.

IGBT module as device for power switching normally encapsulates igbt chip (being designated hereinafter simply as " IGBT ") and diode together, and described IGBT module is mounted on radiator with heat radiation in use.

S102: the thermal impedance Z that determines IGBT in described power electronic equipment to be detected _igbt, described thermal impedance comprises the thermal impedance Z between described IGBT knot and shell _jc-igbtand the thermal impedance Z between described shell and radiator _ch.

Described IGBT knot refers to be packaged in the igbt chip of IGBT inside modules, and described shell refers to the substrate contacting with radiator when IGBT module is mounted on radiator.

S103: the Current Temperatures T that detects described radiator _h.

S104: according to the consume P of IGBT in described power electronic equipment to be detected _igbtconsume P with diode _diode, the thermal impedance Z of IGBT in described power electronic equipment to be detected _igbt, described radiator Current Temperatures T _h, according to default formula, calculate the junction temperature T of IGBT in described power electronic equipment to be detected _j-igbt.

S105: judge described junction temperature T _j-igbtwhether be greater than preset temperature, if so, stop sending the driving signal of IGBT, described IGBT quits work.

Visible; the present invention has detected thermal impedance between thermal impedance between IGBT knot and shell and shell and radiator; and considered to be packaged in the impact of diode heating on IGBT junction temperature in IGBT module simultaneously; in prior art, by detecting radiator temperature, do the overheat protector of IGBT module; testing result is more accurate; and then report to the police when IGBT excess temperature, avoided burning of IGBT module.

On the basis of the embodiment providing in the invention described above, preferred, described default formula can be: T _j-igbt=T _h+ (P _igbt+ P _diode) * Z _ch+ P _igbt* Z _jc-igbt.The computing formula of IGBT junction temperature is T _j=P*Z+T _h, wherein, Tj is the junction temperature of IGBT in power electronic equipment to be detected, and P is the consume of IGBT in power electronic equipment to be detected, and Z is the thermal impedance of IGBT in power electronic equipment to be detected, T _hcurrent Temperatures for radiator.

If directly adopt said method to obtain IGBT junction temperature, can make the junction temperature of the IGBT that finally obtains on the low side.Due to be encapsulated in diode in IGBT module can be when igbt chip be idle conducting and turn-offing in igbt chip work; can produce certain temperature rise; can produce certain impact to the temperature of igbt chip; therefore only has the impact of simultaneously considering diode pair igbt chip; the IGBT junction temperature finally obtaining is only and more approaches its true temperature, makes the thermal overload protection of electronic equipment more timely.Consider after above-mentioned factor, the present invention has adopted the method for the following IGBT of obtaining junction temperature: T _j-igbt=T _h+ Δ T _ch+ Δ T _jc=T _h+ (P _igbt+ P _diode) * Z _ch+ P _igbt* Z _jc-igbt, Δ T wherein _chfor shell is to the temperature rise between radiator, Δ T _jcfor IGBT ties the temperature rise between shell.

Except this, the present embodiment also provides two kinds of specific implementations of determining IGBT and diode consume in power electronic equipments to be detected.The first is: calculate in the first Preset Time, the average loss of IGBT and diode in described power electronic equipment to be detected, described average loss comprises the switch consume of IGBT and diode in the conducting consume of IGBT and diode in described power electronic equipment to be detected and described power electronic equipment to be detected.The second is: calculate IGBT and the real-time consume of diode in switch periods in described power electronic equipment to be detected, described real-time consume comprises the switch consume of IGBT and diode in the conducting consume of IGBT and diode in power electronic equipment to be detected and power electronic equipment to be detected.The consume of IGBT in power electronic equipment take below as example describes its computational methods in detail, by following method, can obtain equally the conduction loss P of diode _cond.dioderecovery loss P with diode _sw.diode.

In the first account form, in power electronic equipment to be detected, the conducting of IGBT consume is: wherein, V _ce0the fixed pressure drop of emitter and inter-collector during for the conducting of IGBT in power electronic equipment to be detected, i _peakfor the maximum current of IGBT in described power electronic equipment to be detected, R _ce0for the impedance of emitter and the inter-collector when the conducting of IGBT in power electronic equipment to be detected, m is modulation ratio,

for power factor.

In described power electronic equipment to be detected, the consume of the switch of IGBT is:

wherein, f _swfor the switching frequency of IGBT in power electronic equipment to be detected, E _onfor the loss producing during IGBT conducting in power electronic equipment to be detected, E _offthe loss producing while turn-offing for IGBT in power electronic equipment to be detected, I _nomfor measuring current, V _dcfor direct voltage, V _nomfor test voltage.

In described the second detection mode, in described power electronic equipment to be detected, the conducting of IGBT consume is: P _cond.igbt=(V _ce0+ R _ce0i) * i* τ; Wherein, V _ce0the fixed pressure drop of emitter and inter-collector during for the conducting of IGBT in power electronic equipment to be detected.

In described power electronic equipment to be detected, the consume of the switch of IGBT is:

wherein, f _swfor the switching frequency of IGBT in power electronic equipment to be detected, E _onfor the loss producing during IGBT conducting in power electronic equipment to be detected, E _offthe loss producing while turn-offing for IGBT in power electronic equipment to be detected, I _nomfor measuring current, V _dcfor direct voltage, V _nomfor test voltage.

Except this, the present embodiment also provides a kind of mode of determining the thermal impedance of IGBT in power electronic equipment to be detected, is specially: the thermal impedance curve according to IGBT, can obtain thermal resistance R _chand timeconstantτ, it should be noted that here, each IGBT all has specific thermal impedance curve, and the manufacturer that this thermal impedance curve is generally IGBT provides., in power electronic equipment to be detected, the knot of IGBT and the computing formula of the thermal impedance between shell are as follows, the parameters R in following formula ₁, R ₂, R ₃, R ₄and t ₁, t ₂, t ₃, t ₄can obtain by the IGBT thermal impedance curve that crusts:

$Z_{\mathrm{jc}-\mathrm{igbt}}=R_1(1-e^{(-\frac{t}{t_1})})+R_2(1-e^{(-\frac{t}{t_2})})+R_3(1-e^{(-\frac{t}{t_3})})+R_4(1-e^{(-\frac{t}{t_4})})$

In power electronic equipment to be detected, the shell of IGBT and the thermal impedance between radiator are

r wherein _chfor shell is to the thermal resistance between radiator, τ is that shell is to the time constant of thermal impedance between radiator, R _chand τ can obtain according to hot simulation calculation.Concrete, the computational process of τ is: the temperature rise curve according to IGBT shell to radiator, and as shown in Figure 2, utilize capacitor charging principle known, 3 τ will reach 95%, just in time reach 95% while stablizing so τ=9.55/3=3.18s while can read 9.55s from Fig. 2.

From above-mentioned formula, can draw the temperature rise between the knot of IGBT power electronic equipment to be detected and shell $\mathrm{\Δ}{T}_{\mathrm{jc}}=P_{\mathrm{igbt}}*Z_{\mathrm{jc}-\mathrm{igbt}}=(P_{\mathrm{cond}.\mathrm{igbt}}+P_{\mathrm{sw}.\mathrm{igbt}})*R_1(1-e^{(-\frac{t}{t_1})})+R_2(1-e^{(-\frac{t}{t_2})})+R_3(1-e^{(-\frac{t}{t_3})})+R_4(1-e^{(-\frac{t}{t_4})}),$ According to structure and the Duct design of concrete unit, utilize software to carry out hot emulation and obtain shell to the temperature rise curve of radiator test point again, utilize this curve calculation to go out shell to thermal resistance R between radiator _chand timeconstantτ, and obtain shell to the temperature rise of radiator ${\mathrm{\ΔT}}_{\mathrm{ch}}=(P_{\mathrm{igbt}}+P_{\mathrm{diode}})*Z_{\mathrm{ch}}=(P_{\mathrm{cond}.\mathrm{igbt}}+P_{\mathrm{sw}.\mathrm{igbt}}+P_{\mathrm{cond}.\mathrm{diode}}+P_{\mathrm{sw}.\mathrm{diode}})*R_{\mathrm{ch}}(1-e^{(-\frac{t}{\mathrm{\τ}})}),$ And then according to following formula: T _j-igbt=T _h+ Δ T _ch+ Δ T _jc=T _h+ (P _igbt+ P _diode) * Z _ch+ P _igbt* Z _jc-igbt, can obtain the real-time junction temperature of igbt chip.

Visible; the invention provides a kind of thermal overload protection method of power electronic equipment; by the thermal impedance of IGBT in IGBT and the consume of diode, power electronic equipment to be detected in definite power electronic equipment to be detected and the Current Temperatures that detects radiator; wherein, thermal impedance comprises thermal impedance between described IGBT knot and shell and the thermal impedance between described shell and radiator.According to default formula, calculate the junction temperature of IGBT in described power electronic equipment to be detected afterwards.Finally, judge whether described junction temperature is greater than preset temperature, if so, stop sending the driving signal of IGBT, described IGBT quits work.The present invention has detected thermal impedance between thermal impedance between IGBT knot and shell and shell and radiator; and considered to be packaged in the impact of diode heating on IGBT junction temperature in IGBT module simultaneously; in prior art, by detecting radiator temperature, do the overheat protector of IGBT module; testing result is more accurate; and then report to the police when IGBT excess temperature, avoided burning of IGBT module.

In the embodiment that the invention described above provides, describe method in detail, for method of the present invention, can adopt the device of various ways to realize, so the present invention also provides a kind of device, provided specific embodiment below and be elaborated.

Refer to Fig. 3, the structural representation for the heat overload protector of a kind of power electronic equipment provided by the invention, comprising:

The first determination module 101, for determining the consume P of power electronic equipment IGBT to be detected _igbtconsume P with diode _diode.

The second determination module 102, for determining the thermal impedance Z of described power electronic equipment IGBT to be detected _igbt, described thermal impedance comprises the thermal impedance Z between described IGBT knot and shell _jc-igbtand the thermal impedance Z between described shell and radiator _ch.

Detection module 103, for detection of the Current Temperatures T of described radiator _h.

Processing module 104, for according to the consume P of described IGBT _igbtconsume P with diode _diode, the thermal impedance Z of IGBT in described power electronic equipment to be detected _igbt, described radiator Current Temperatures T _h, according to default formula, calculate the junction temperature T of IGBT in described power electronic equipment to be detected _j-igbt.

Judge module 105, for judging whether described junction temperature is greater than preset temperature, if so, stops sending the driving signal of IGBT, and described IGBT quits work.

It should be noted that, the operation principle of the heat overload protector of this power electronic equipment is referring to embodiment of the method, again repeated description not.

Except this, the present embodiment also provides a kind of IGBT system for detecting temperature, comprises the heat overload protector of above-mentioned power electronic equipment.

In sum: a kind of thermal overload protection method that the invention provides power electronic equipment; by the thermal impedance of IGBT and the Current Temperatures that detects radiator in the transient state consume of IGBT and diode in definite power electronic equipment to be detected, power electronic equipment to be detected; wherein, thermal impedance comprises thermal impedance between described IGBT knot and shell and the thermal impedance between described shell and radiator.According to default formula, calculate the junction temperature of IGBT in described power electronic equipment to be detected afterwards.Finally, judge whether described junction temperature is greater than preset temperature, if so, stop sending the driving signal of IGBT, described IGBT quits work.Visible; the present invention has detected thermal impedance between thermal impedance between IGBT knot and shell and shell and radiator; and considered to be packaged in the impact of diode heating on IGBT junction temperature in IGBT module simultaneously; in prior art, by detecting radiator temperature, do the overheat protector of IGBT module; testing result is more accurate; and then report to the police when IGBT excess temperature, avoided burning of IGBT module.

In this specification, each embodiment adopts the mode of going forward one by one to describe, and each embodiment stresses is the difference with other embodiment, between each embodiment identical similar part mutually referring to.For the device providing for embodiment, because its method providing with embodiment is corresponding, so description is fairly simple, relevant part partly illustrates referring to method.

Above-mentioned explanation to provided embodiment, makes professional and technical personnel in the field can realize or use the present invention.To the multiple modification of these embodiment, will be apparent for those skilled in the art, General Principle as defined herein can, in the situation that not departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle provided in this article and features of novelty.

Claims (10)

1. a thermal overload protection method for power electronic equipment, is applied to power electronic equipment, and described power electronic equipment comprises IGBT module, and IGBT and diode that described IGBT module comprises and connects, is characterized in that, comprising:

Determine the consume P of IGBT in power electronic equipment to be detected _igbtconsume P with diode _diode;

Determine the thermal impedance Z of IGBT in described power electronic equipment to be detected _igbt, described thermal impedance comprises the thermal impedance Z between described IGBT knot and shell _jc-igbtand the thermal impedance Z between described shell and radiator _ch;

Detect the Current Temperatures T of described radiator _h;

According to the consume P of IGBT in described power electronic equipment to be detected _igbtconsume P with diode _diode, the thermal impedance Z of IGBT in described power electronic equipment to be detected _igbt, described radiator Current Temperatures T _h, according to default formula, calculate the junction temperature T of IGBT in described power electronic equipment to be detected _j-igbt;

Judge described junction temperature T _j-igbtwhether be greater than preset temperature, if so, stop sending the driving signal of IGBT, described IGBT quits work.

2. the thermal overload protection method of power electronic equipment according to claim 1, is characterized in that, calculates described IGBT junction temperature T _j-igbtdefault formula be: T _j-igbt=T _h+ (P _igbt+ P _diode) * Z _ch+ P _igbt* Z _jc-igbt.

3. the thermal overload protection method of power electronic equipment according to claim 1, is characterized in that, in described definite power electronic equipment to be detected, the consume of IGBT or diode comprises:

Calculate in the first Preset Time, the average loss of IGBT or diode in described power electronic equipment to be detected, described average loss comprises the switch consume of IGBT in the conducting consume of IGBT in described power electronic equipment to be detected or diode and described power electronic equipment to be detected or diode.

4. the thermal overload protection method of power electronic equipment according to claim 3, is characterized in that, in described power electronic equipment to be detected, the conducting of IGBT consume is: wherein, V _ce0the fixed pressure drop of emitter and inter-collector during for the conducting of IGBT in power electronic equipment to be detected, i _peakfor the maximum current of IGBT in described power electronic equipment to be detected, R _ce0for the impedance of emitter and the inter-collector when the conducting of IGBT in power electronic equipment to be detected, m is modulation ratio,

for power factor.

5. the thermal overload protection method of power electronic equipment according to claim 3, is characterized in that, in described power electronic equipment to be detected, the consume of the switch of IGBT is:

wherein, f _swfor the switching frequency of IGBT in power electronic equipment to be detected, E _onfor the loss producing during IGBT conducting in power electronic equipment to be detected, E _offthe loss producing while turn-offing for IGBT in power electronic equipment to be detected, I _nomfor measuring current, V _dcfor direct voltage, V _nomfor test voltage.

6. the thermal overload protection method of power electronic equipment according to claim 1, is characterized in that, in described definite power electronic equipment to be detected, the consume of IGBT or diode comprises:

Calculate IGBT or the real-time consume of diode in switch periods in described power electronic equipment to be detected, described real-time consume comprises the switch consume of IGBT in the conducting consume of IGBT in power electronic equipment to be detected or diode and power electronic equipment to be detected or diode.

7. the thermal overload protection method of power electronic equipment according to claim 6, is characterized in that, in described power electronic equipment to be detected, the conducting of IGBT consume is: P _cond.igbt=(V _ce0+ R _ce0i) * i* τ; Wherein, V _ce0the fixed pressure drop of emitter and inter-collector during for the conducting of IGBT in power electronic equipment to be detected, R _ce0for the impedance of emitter and the inter-collector when the conducting of IGBT in power electronic equipment to be detected, τ is that shell is to the time constant of radiator test point thermal impedance.

8. the thermal overload protection method of power electronic equipment according to claim 6, is characterized in that, in described power electronic equipment to be detected, the consume of the switch of IGBT is:

wherein, f _swfor the switching frequency of IGBT in power electronic equipment to be detected, E _onfor the loss producing during IGBT conducting in power electronic equipment to be detected, E _offthe loss producing while turn-offing for IGBT in power electronic equipment to be detected, I _nomfor measuring current, V _dcfor direct voltage, V _nomfor test voltage.

9. a heat overload protector for power electronic equipment, is characterized in that, comprising:

The first determination module, for determining the consume P of power electronic equipment IGBT to be detected _igbtconsume P with diode _diode;

The second determination module, for determining the thermal impedance of described power electronic equipment IGBT to be detected, described thermal impedance Z _igbtcomprise the thermal impedance Z between described IGBT knot and shell _jc-igbtand the thermal impedance Z between described shell and radiator _ch;

Detection module, for detection of the Current Temperatures T of described radiator _h;

Processing module, for according to the consume P of described power electronic equipment IGBT to be detected _igbtconsume P with diode _diode, the thermal impedance Z of IGBT in described power electronic equipment to be detected _igbt, described radiator Current Temperatures T _h, according to default formula, calculate the junction temperature T of IGBT in described power electronic equipment to be detected _j-igbt;

Judge module, for judging whether described junction temperature is greater than preset temperature, if so, stops sending the driving signal of IGBT, and described IGBT quits work.

10. a thermal overload protection system for power electronic equipment, is characterized in that, comprises the heat overload protector of power electronic equipment and power electronic equipment as claimed in claim 9.

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