CN213484835U

CN213484835U - Multiple overcurrent protection device applied to PFC

Info

Publication number: CN213484835U
Application number: CN202022562985.0U
Authority: CN
Inventors: 陆梦娇
Original assignee: Suzhou Aier Zhike Frequency Conversion Technology Co ltd
Current assignee: Suzhou Aier Zhike Frequency Conversion Technology Co ltd
Priority date: 2020-11-09
Filing date: 2020-11-09
Publication date: 2021-06-18
Anticipated expiration: 2030-11-09

Abstract

The utility model discloses a be applied to multiple overcurrent protection device of PFC, the hardware protection includes first comparator, current sensor, the second comparator, the timing chip, first triode, the second triode, the third triode, fourth triode and fifth triode, wherein, current sensor is connected with the positive foot of first comparator, the output foot of first comparator is connected with the negative foot of second comparator, the output foot of second comparator is connected with the trigger pin of timing chip through first pull-up resistance connection pull-up power supply, the output pin of timing chip is connected with the base of first triode, a plurality of triodes connect gradually, the collecting electrode of fifth triode is connected with the power end of the drive chip of protected electronic switch pipe; the software protection includes an APFC switch connected to both the collector of the third transistor and the base of the fourth transistor through a first current limiting resistor. The utility model discloses realize that hardware triggers and software exert oneself multiple overcurrent protection of output.

Description

Multiple overcurrent protection device applied to PFC

Technical Field

The utility model relates to an overcurrent protection field especially relates to a be applied to multiple overcurrent protection device of PFC.

Background

The existing digital PFC (Power Factor Correction) control technology usually detects a current value when overcurrent protection is implemented, and stops PWM wave output when a set current value is exceeded, thereby achieving the purpose of overcurrent protection.

However, the protection in the prior art is too single, the software reaction has a certain time delay, and the protection effect is lost when the software fails.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem that exists among the prior art, the utility model provides a be applied to PFC's multiple overcurrent protection device introduces hardware protection and software protection simultaneously, realizes multiple overcurrent protection to IGBT. The technical scheme is as follows:

the utility model provides a multiple overcurrent protection device applied to PFC, which comprises a hardware overcurrent protection module and a software overcurrent protection module, wherein,

the hardware overcurrent protection module comprises a first comparator, a current sensor, a second comparator, a timing chip, a first triode, a second triode, a third triode, a fourth triode and a fifth triode, wherein a negative pin of the first comparator is connected with an upper pull power supply through a first divider resistor, the current sensor is connected with a positive pin of the first comparator, an output pin of the first comparator is connected with a negative pin of the second comparator, a positive pin of the second comparator is connected with the upper pull power supply through a second upper divider resistor, an output pin of the second comparator is connected with the upper pull power supply through a first pull-up resistor and is simultaneously connected with a trigger pin of the timing chip, an output pin of the timing chip is connected with a base electrode of the first triode, a collector electrode of the first triode is connected with the upper pull power supply through the first pull-up resistor and is also connected with a base electrode of the second triode, the collector of the second triode is connected with the base of the third triode, the collector of the third triode is connected with the base of the fourth triode, the collector of the fourth triode is connected with the base of the fifth triode, and the collector of the fifth triode is connected with the power supply end of the driving chip of the protected electronic switching tube;

the software overcurrent protection module comprises an APFC switch which is simultaneously connected with a collector electrode of the third triode and a base electrode of the fourth triode through the first current limiting resistor.

Furthermore, the software overcurrent protection module further comprises an APFC PWM output switch, and the APFC PWM output switch is connected with the input end of the driving chip through software output.

Further, the first triode, the second triode, the third triode and the fourth triode are NPN triodes, and the fifth triode is a PNP triode.

Furthermore, the emitting electrodes of the first triode, the second triode, the third triode and the fourth triode are grounded together.

Further, the protected electronic switching tube is an IGBT.

Further, the resistance value of the first current limiting resistor is 5.1K Ω, and the resistance value of the second current limiting resistor is 1K Ω.

Further, the collector of the second triode is connected with a pull-up power supply through a second pull-up resistor.

Furthermore, the pull-up power supplies of the first comparator, the second comparator and the first triode are all 5V.

Furthermore, the fifth triode is a PNP triode, and the base of the fifth triode is connected to the collector of the fourth triode through a resistor.

Further, the APFC switch and the APFC PWM output switch are controlled by software.

The utility model provides a beneficial effect that technical scheme brought as follows:

a. the principle of hardware overcurrent protection is that when an overcurrent condition occurs, a power supply signal outputting a PWM wave is directly cut off to realize protection;

b. the principle of software overcurrent protection is that an IO port is set as a switching signal to realize the on/off protection function; and the other IO port is set as a PWM signal output port to realize the function of controlling output signals.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a first partial circuit diagram of a multiple overcurrent protection device applied to a PFC according to an embodiment of the present invention;

fig. 2 is a second partial circuit diagram of the multiple overcurrent protection device applied to the PFC according to the embodiment of the present invention.

Wherein the reference numerals include: 1-a first comparator, 2-a current sensor, 3-a second comparator, 4-a timing chip, 5-a first triode, 6-a second triode, 7-a third triode, 8-a fourth triode, 9-a fifth triode, 10-a driving chip, 11-a protected electronic switching tube, 12-an APFC switch and 13-an APFC PWM output switch.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

In one embodiment of the present invention, a multiple overcurrent protection device for use in PFCs is provided, as shown in fig. 1 and 2, comprising a hardware overcurrent protection module and a software overcurrent protection module, wherein,

the hardware overcurrent protection module comprises a first comparator 1, a current sensor 2, a second comparator 3, a timing chip 4, a first triode 5, a second triode 6, a third triode 7, a fourth triode 8 and a fifth triode 9, wherein a negative pin of the first comparator 1 is connected with a pull-up power supply (optionally 5V) through a first divider resistor, the current sensor 2 is connected with a positive pin of the first comparator 1, an output pin of the first comparator 1 is connected with a negative pin of the second comparator 3, a positive pin of the second comparator 3 is connected with the pull-up power supply (optionally 5V) through a second divider resistor, an output pin of the second comparator 3 is connected with a trigger pin of the timing chip 4 while being connected with the pull-up power supply (optionally 5V) through the first pull-up resistor, an output pin of the timing chip 4 is connected with a base electrode of the first triode 5, the collector of the first triode 5 is connected with a pull-up power supply (optionally 5V) through a first pull-up resistor, and is also connected with the base of the second triode 6, the collector of the second triode 6 is connected with the base of the third triode 7, the collector of the third triode 7 is connected with the base of the fourth triode 8, the collector of the fourth triode 8 is connected with the base of the fifth triode 9, the collector of the fifth triode 9 is connected with the power supply end of the driving chip 10 of the protected electronic switch tube 11, because the circuit diagram of the hardware overcurrent protection module is large, the hardware overcurrent protection module is further divided into fig. 1 and fig. 2 for convenience of reference, the overcurrent protection in fig. 1 and the overcurrent protection in fig. 2 are the same node, namely, an overcurrent protection point is formed between the first triode 5 and the second triode 6, when the overcurrent protection signal of the overcurrent protection point outputs a low level, the fifth triode 9 is in an off state, and the 15V voltage connected to the emitter thereof cannot supply power to the driving chip 10(IC203), that is, the driving chip 10 cannot work, so that the protected electronic switching tube 11 (in this embodiment, an IGBT) cannot be turned on;

the software overcurrent protection module comprises an APFC switch 12, the APFC switch is connected with a collector electrode of a third triode 7 and a base electrode of a fourth triode 8 through a first current limiting resistor (the resistance value can be selected to be 5.1K omega), the APFC is Active Power Factor Correction, Active Power Factor Correction is conducted, the APFC switch is used for protecting software output, and therefore overcurrent protection of a final circuit is achieved, IGBT damage is prevented, and double protection is provided in cooperation with hardware overcurrent protection.

In one embodiment, the software overcurrent protection module further includes an APFC PWM output switch 13, which is connected to the input terminal of the driver chip 10 through a second current limiting resistor (the resistance value may be 1K Ω), the APFC switch 12 and the APFC PWM output switch 13 are both controlled by software, and the APFC PWM output is a protection of software output, so as to implement overcurrent protection of a final circuit and implement a third protection.

In a specific embodiment, the first transistor 5, the second transistor 6, the third transistor 7, and the fourth transistor 8 are NPN transistors; the base electrodes of the first triode 5, the second triode 6 and the third triode 7 are grounded together with the emitting electrode through a pull-down resistor, and the collector electrode of the second triode 6 is also connected with a pull-up power supply (optional 5V) through a second pull-up resistor.

And the fifth triode 9 is a PNP triode, and the base of the fifth triode 9 is connected to a pull-up power supply (15V, which is used as a power supply of the driving chip) through a pull-up resistor and an emitter.

The utility model discloses realize multiple overcurrent protection's principle as follows:

overcurrent protection is realized by using a simple triode, and when an overcurrent phenomenon occurs in the circuit, the overcurrent protection of hardware cuts off the power supply of the driving chip IC203 (the pull-up power supply 15V of the fifth triode 9 in FIG. 2) and stops PWM wave output; when software detects the low level of the overcurrent, on one hand, the switch control of the APFC is switched to an off state, and on the other hand, the PMW wave output is stopped, so that the IGBT is prevented from being burnt out due to the overcurrent through triple protection of hardware and software, the cost is controlled, and the low-cost, safe and reliable effect is realized.

The utility model discloses a circuit working process of overcurrent protection device when taking place to overflow as follows:

when the current increases, the current sensor 2 detects that the voltage value increases, and when the negative pin access voltage of the first comparator 1 is exceeded, the first comparator 1 outputs a high level, and at this time, the output pin of the first comparator 1 outputs a high level and exceeds the positive pin access voltage of the second comparator 3, so that the pin 7 of the second comparator 3 outputs a low level. The low level is input into the timing chip 4, the pin 3 of the timing chip 4 outputs the high level for a certain time, and then the overcurrent protection signal is output as the low level through the first triode 5.

When the overcurrent protection signal is pulled down, on one hand, the chip enters an interrupt state when detecting a low level through an IO port of the chip, and the following overcurrent protection operation is performed: 1. stopping APFC PWM wave output (the output is 0), setting the output point of the drive chip IC203 to be 0, and enabling the IGBT not to be conducted; the APFC switch output is low (output is 0).

When any one of the point voltage output by the first triode 5 and the point voltage output by the third triode 7 is at a low level, the fifth triode 9(Q280) is in an off state, and the pull-up power supply (15V) cannot supply power to the driving chip 10(IC203) through the fifth triode 9, that is, the IGBT cannot be turned on.

Through the above, the first triode 5 outputs the overcurrent protection signal as hardware trigger protection, and the output of the APFC switch and the APFC PWM is the protection of software output, so that the multiple overcurrent protection of the final circuit is realized, and the service life of the IGBT is prolonged.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A multiple overcurrent protection device applied to PFC is characterized by comprising a hardware overcurrent protection module and a software overcurrent protection module, wherein,

the hardware overcurrent protection module comprises a first comparator (1), a current sensor (2), a second comparator (3), a timing chip (4), a first triode (5), a second triode (6), a third triode (7), a fourth triode (8) and a fifth triode (9), wherein a negative pin of the first comparator (1) is connected with a pull-up power supply through a first divider resistor, the current sensor (2) is connected with a positive pin of the first comparator (1), an output pin of the first comparator (1) is connected with a negative pin of the second comparator (3), the positive pin of the second comparator (3) is connected with the pull-up power supply through a second divider resistor, an output pin of the second comparator (3) is connected with a trigger pin of the timing chip (4) while being connected with the pull-up power supply through the first pull-up resistor, and an output pin of the timing chip (4) is connected with a base electrode of the first triode (5), the collector of the first triode (5) is connected with a pull-up power supply through a first pull-up resistor and is also connected with the base of a second triode (6), the collector of the second triode (6) is connected with the base of a third triode (7), the collector of the third triode (7) is connected with the base of a fourth triode (8), the collector of the fourth triode (8) is connected with the base of a fifth triode (9), and the collector of the fifth triode (9) is connected with the power supply end of a driving chip (10) of a protected electronic switching tube (11);

the software overcurrent protection module comprises an APFC switch (12) which is simultaneously connected with a collector electrode of a third triode (7) and a base electrode of a fourth triode (8) through a first current limiting resistor.

2. The multiple overcurrent protection device of claim 1, wherein the software overcurrent protection module further comprises an APFC PWM output switch (13) connected to the input of the driver chip (10) through a second current limiting resistor.

3. The multiple overcurrent protection device according to claim 1, wherein the first transistor (5), the second transistor (6), the third transistor (7) and the fourth transistor (8) are NPN transistors, and the fifth transistor (9) is a PNP transistor.

4. The multiple overcurrent protection device according to claim 1, wherein the emitters of the first transistor (5), the second transistor (6), the third transistor (7) and the fourth transistor (8) are commonly grounded.

5. Multiple overcurrent protection device according to claim 1, characterized in that the protected electronic switching tube (11) is an IGBT.

6. The multiple overcurrent protection device of claim 2, wherein the first current limiting resistor has a resistance of 5.1K Ω and the second current limiting resistor has a resistance of 1K Ω.

7. The multiple overcurrent protection device as claimed in claim 1, wherein the collector of the second transistor (6) is further connected to a pull-up power supply via a second pull-up resistor.

8. The multiple overcurrent protection device according to claim 1, wherein the pull-up power supplies of the first comparator (1), the second comparator (3) and the first triode (5) are all 5V.

9. The multiple overcurrent protection device as claimed in claim 1, wherein the fifth transistor (9) is a PNP transistor, and a base of the fifth transistor (9) is connected to a collector of the fourth transistor (8) via a resistor.

10. The multiple overcurrent protection device of claim 2, wherein the APFC switch (12) and the APFC PWM output switch (13) are both software controlled.