CN201918714U - Overheating protection circuit of IGBT (Insulated Gate Bipolar Translator) module - Google Patents

Abstract

The utility model discloses an overheating protection circuit of an IGBT (Insulated Gate Bipolar Translator) module, which comprises a three-terminal adjustable shunting reference source TL431, resistors R1-R9, a resistance temperature sensor RT with a negative temperature coefficient, LM324N operational amplifiers U1A, U1B, U1C and U1D and capacitors C1 and C2. In the overheating protection circuit of the IGBT module, the advantage of accurate temperature detection by the temperature sensor packaged in the IGBT module is utilized, and the defect that an added linear optocoupler is not suitable to be used on a large scale because of higher cost in the common production method is overcome; compared with the production method that the temperature sensor is installed on the surface of a radiator for overheating protection, overheating protection accuracy is greatly improved under the condition of adding little cost; IGBT shell temperature Tc is sampled by the temperature sensor in the IGBT module under the condition that cost is not substantially increased because of adding the linear optocoupler isolation; and overheating protection is carried out at the accurate temperature.

Description

A kind of IGBT module thermal-shutdown circuit

Technical field

The utility model relates to the power technology field, particularly relates to a kind of IGBT module thermal-shutdown circuit.

Background technology

IGBT is easy to drive, control the advantage simple, that switching frequency is high because of its existing power MOSFET; there is the transistorized conducting voltage of power low again; the advantage that on state current is big and in the power electronics industry, being extensive use of; and the one of the main reasons of IGBT module damage to be long-time junction temperature too high and the damage that causes is protected so tackle it when its excess temperature.

At present; the general way of IGBT module overheat protector is to detect spreader surface temperature T s at the spreader surface mounting temperature sensor that the IGBT module is installed; calculate the threshold value of the junction temperature Tj of IGBT with the setting overheat protector according to module thermal resistance or experience, the pulse signal by software blocked IGBT when excess temperature takes place quits work it to turn-off IGBT.But the thermal resistance between spreader surface and the IGBT module substrate will produce bigger inconsistency in assembling process; and the test point of temperature sensor also may cause not being the maximum temperature point of radiator because of the condition in the external world, more than 2 IGBT junction temperatures that all may directly cause calculating and virtual junction temperature according to the test point temperature differ too greatly and make defencive function work undesired.

In recent years in the module of some new encapsulating structures of IGBT, inside is packaged with temperature sensor (N T C), and it is the stable state shell temperature (Tc) of detection power module effectively.The NTC parameter of encapsulation is identical in the module.The temperature sensor that will be used for measurement module shell temperature directly is encapsulated in the interior ceramic substrate (DCB) of module, can simplify the measuring process of module case temperature Tc greatly, and because of it is encapsulated in inside modules, consistency is very high, so that the junction temperature Tj accuracy that shell temperature Tc extrapolates improve greatly.But, must satisfy maintenance safety isolation between any age at failure that may occur according to the requirement of EN50178.Since in the IGBT module NTC may expose under high pressure (for example: during the short circuit or module burn the back), the user also must carry out safe isolation from the outside.Now common practice is to be to deliver to the logic control part after analog signal is isolated with linear optical coupling with temperature inversion, judges that by software state of temperature protects.And the cost of linear optical coupling is higher, is unsuitable for use in enormous quantities.

The utility model content

The purpose of this utility model is to avoid weak point of the prior art and a kind of IGBT module thermal-shutdown circuit is provided.

The purpose of this utility model realizes by following technical measures.

A kind of IGBT module thermal-shutdown circuit comprises the adjustable shunting a reference source of three ends TL431, resistance R 1-R9, negative temperature coefficient resister temperature sensor RT, LM324N operational amplifier U1A, U1B, U1C, U1D, capacitor C 1 and C2;

Public termination+the 15V of R1 and R2, the negative pole of another termination TL431 of R1, the end of RT and the normal phase input end of U1C, the plus earth of TL431 also connects the end of R4, the other end of R4 and the other end of RT connect the adjustable side of TL431 jointly, the normal phase input end of the other end of R2 and the public termination U1A of R3, the other end ground connection of R3, the end of the output termination R5 of the inverting input of U1A and U1A, the end of another termination R6 of R5 and the normal phase input end of U1B, the output of another termination U1B of R6 and the inverting input of U1D, the inverting input of U1B connects the end of R7, output and the inverting input of another termination U1C of R7;

The end of the positive supply termination R8 of U1D and the end of C1, another termination+15V of R8, the output of another termination U1D of C1, the positive input end grounding of U1D; The end of the negative supply termination R9 of U1D and the end of C2, another termination-15V of R9, the output of another termination U1D of C2.

The temperature sensor temperature detection that the utility model utilizes IGBT inside modules encapsulation is advantage accurately; overcome the defective of the higher improper use in enormous quantities of linear optical coupling cost that increases in the common way again; compare the way of carrying out overheat protector at the spreader surface mounting temperature sensor, exceeding the accuracy that has improved overheat protector under the increase condition of cost greatly.And under the situation that does not cause cost significantly to increase, utilize IGBT inside modules temperature sensor sampling IGBT shell temperature Tc because of the isolation of increase linear optical coupling, carrying out overheat protector under the temperature accurately.

Description of drawings

Utilize accompanying drawing that the utility model is described further, but the content in the accompanying drawing does not constitute any restriction of the present utility model.

Fig. 1 is the circuit diagram of an embodiment of IGBT module thermal-shutdown circuit of the present utility model.

Fig. 2 is the resistance and the temperature profile of the temperature sensor that adopts of embodiment of IGBT module thermal-shutdown circuit of the present utility model.

Embodiment

The utility model is described in further detail with the following Examples.

An embodiment of IGBT module thermal-shutdown circuit of the present utility model comprises the adjustable shunting a reference source of three ends TL431, resistance R 1-R9, negative temperature coefficient resister temperature sensor RT, LM324N operational amplifier U1A, U1B, U1C, U1D, capacitor C 1 and C2 as shown in Figure 1.

Public termination+the 15V of R1 and R2, the negative pole of another termination TL431 of R1, the end of RT and the normal phase input end of U1C, the plus earth of TL431 also connects the end of R4, the other end of R4 and the other end of RT connect the adjustable side of TL431 jointly, the normal phase input end of the other end of R2 and the public termination U1A of R3, the other end ground connection of R3, the end of the output termination R5 of the inverting input of U1A and U1A, the end of another termination R6 of R5 and the normal phase input end of U1B, the output of another termination U1B of R6 and the inverting input of U1D, the inverting input of U1B connects the end of R7, output and the inverting input of another termination U1C of R7.

The end of the positive supply termination R8 of U1D and the end of C1, another termination+15V of R8, the output of another termination U1D of C1, the positive input end grounding of U1D; The end of the negative supply termination R9 of U1D and the end of C2, another termination-15V of R9, the output of another termination U1D of C2.

With reference to figure 1 and Fig. 2, TL431 and R1, the voltage stabilizing circuit that Rt, R4 form is converted into 1. voltage Vi with the resistance of Rt; Obtain 2. point voltage Vref after R2 and the R3 dividing potential drop; Vi and Vref isolate the back as U1B and R5 by the voltage follower of U1C and U1A respectively, R6, the input voltage and the reference voltage of the hysteresis comparator that R7 forms, the lower voltage limit of hysteresis comparator and return difference are by Vref, R5, the R6 decision, U1D is as the output circuit of device; R8, R9, C1, C2 is as the power supply circuit of amplifier.

When the temperature sensing actuator temperature surpasses on the set point in limited time, Vi just is lower than the lower limit threshold, and U1B upset output low level is made comparisons with ground by U1D, and U1D output LOCK signal is+15V to be directly used in the transmission of blockade IGBT pulse signal; When the temperature sensing actuator temperature was lower than temperature return difference point, Vi just surpassed the voltage back diffirence point, and U1B upset output high level is made comparisons with ground by U1D, and U1D output LOCK signal is-15V to cancel the transmission of blockade IGBT pulse signal.

The LOCK signal also can be used as the over-temperature condition signal, feeds back to the logic control part by the original non-linear optocoupler of drive part.

By this circuit, can not reach the function of utilizing IGBT inside modules temperature sensor to come the IGBT module is carried out overheat protector by optocoupler.

Should be noted that at last; above embodiment only is used to the technical solution of the utility model is described but not to the restriction of the utility model protection range; although the utility model has been done detailed description with reference to preferred embodiment; those of ordinary skill in the art is to be understood that; can make amendment or be equal to replacement the technical solution of the utility model, and not break away from the essence and the scope of technical solutions of the utility model.

Claims (1)

1.1. an IGBT module thermal-shutdown circuit is characterized in that: comprise the adjustable shunting a reference source of three ends TL431, resistance R 1-R9, negative temperature coefficient resister temperature sensor RT, LM324N operational amplifier U1A, U1B, U1C, U1D, capacitor C 1 and C2;

Public termination+the 15V of R1 and R2, the negative pole of another termination TL431 of R1, the end of RT and the normal phase input end of U1C, the plus earth of TL431 also connects the end of R4, the other end of R4 and the other end of RT connect the adjustable side of TL431 jointly, the normal phase input end of the other end of R2 and the public termination U1A of R3, the other end ground connection of R3, the end of the output termination R5 of the inverting input of U1A and U1A, the end of another termination R6 of R5 and the normal phase input end of U1B, the output of another termination U1B of R6 and the inverting input of U1D, the inverting input of U1B connects the end of R7, output and the inverting input of another termination U1C of R7;

The end of the positive supply termination R8 of U1D and the end of C1, another termination+15V of R8, the output of another termination U1D of C1, the positive input end grounding of U1D; The end of the negative supply termination R9 of U1D and the end of C2, another termination-15V of R9, the output of another termination U1D of C2.

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