WO2021256632A1

WO2021256632A1 - Circuit protection device and method

Info

Publication number: WO2021256632A1
Application number: PCT/KR2020/016807
Authority: WO
Inventors: 김성민; 김동욱; 이승호
Original assignee: 한양대학교 에리카산학협력단
Priority date: 2020-06-16
Filing date: 2020-11-25
Publication date: 2021-12-23
Also published as: KR102486844B1; KR20210155463A

Abstract

Disclosed are a circuit protection device and method capable of effectively protecting a circuit from an overcurrent by rapidly blowing a fuse. The circuit protection device, according to one embodiment of the present invention, may comprise: an overcurrent detection unit which detects a current supplied via a fuse from a first electric power, and outputs a control signal when the magnitude of the detected current exceeds a reference value; and a blowing current supply unit which stores electric charge supplied from a second electric power, and, as a response to the control signal, supplies an additional current, generated by the stored electric charge, to the fuse.

Description

Circuit protection devices and methods

The present invention relates to a circuit protection apparatus and method, and more particularly, to a circuit protection apparatus and method capable of effectively protecting a circuit from overcurrent by rapidly blowing a fuse.

In DC system, overcurrent caused by a short circuit accident can cause failure of the DC system.

DC current does not have a zero point, and due to low impedance, the current may rapidly increase with high di/dt when a short circuit occurs.

Therefore, it is necessary to break the circuit within a few milliseconds to protect the circuit when a short circuit accident occurs in the DC system.

In order to protect the DC system from overcurrent, a DC circuit breaker or fuse is generally used.

The fuse has the advantage of being able to completely electrically isolate the fault point and the system to be protected, and is the simplest circuit protection method.

However, the fuse has a disadvantage that it takes a long time to completely blow, and in order to blow within a few tens of ms, a current of several tens of times the rated current of the fuse must flow.

Accordingly, at the time when the fuse is blown, an excessive current that cannot handle the load already flows.

Conventional fuses are used alone, and the melting time is different depending on the object to be protected. In the case of a DC system, a semiconductor fuse having a low thermal limit and a short operating time is used for fast fusing. However, the semiconductor fuse also takes several tens of ms to operate.

Since the semiconductor fuse used in the conventional DC system is a fuse used to prevent burnout of semiconductor elements such as thyristors and diodes, it has a lower thermal limit value than that of thyristors or diodes, and the value is 5- of the rated current of the element. It corresponds to the extent to which 6 times the current flows for 10 ms.

On the other hand, semiconductor devices such as IGBT (Insulated Gate Bipolar Transistor) and MOSFET (Metal Oxide Semiconductor Field Effect Transistor), which are used for switching in most power converters in recent years, are Since it is easily burned out, it may cause a failure of the power converter.

Therefore, when a fuse is used alone in a DC system using an IGBT or MOSFET, even a semiconductor fuse with a fast fusing rate can damage the semiconductor elements of the power converter, leading to a bigger accident and additional economic loss.

In order to reduce the damage to the DC system due to the long fusing time of the fuse, it is necessary to shorten the fusing time of the fuse.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a circuit protection device and method capable of effectively protecting a circuit from overcurrent by rapidly blowing a fuse.

A circuit protection device according to an embodiment of the present invention detects a current supplied from a first power source through a fuse, and outputs a control signal when the sensed current exceeds a reference value from the overcurrent detecting unit and the second power source. and a fusing current supply unit that stores the supplied electric charge and supplies an additional current generated by the stored electric charge to the fuse in response to the control signal.

According to an embodiment, the overcurrent detecting unit may be connected between the first power source and the fuse.

According to an embodiment, the overcurrent detecting unit may include a shunt resistor connected between the first power source and the fuse, a differential amplifier outputting a first voltage corresponding to a voltage between both ends of the shunt resistor, and a difference between the first voltage and the reference voltage. It may include a comparator for outputting a second voltage corresponding to the difference voltage, and a gate driver for outputting the control signal according to the second voltage.

According to an embodiment, the fusing current supply unit may include an additional current generator configured to store the charge supplied from the second power source and a current loop through the fuse, the overcurrent detector, and the additional current generator in response to the control signal. It may include a switching unit that generates

According to an embodiment, the additional current generator may include an insulating converter that converts the second power into DC power, and a capacitor that stores the charge supplied from the DC power.

According to an embodiment, the switching unit may include a switching element that connects the fuse to the additional current generating unit in response to the control signal.

According to an embodiment, the switching unit may further include a diode connected between the fuse and the switching element.

A circuit protection method of a circuit protection device according to an embodiment of the present invention blocks an overcurrent flowing from a first power source to a load, storing the charge supplied from the second power source, detecting the current supplied from the first power source The method may include generating a control signal when the magnitude of the current exceeds a predetermined value, and supplying the stored charge to a fuse in response to the control signal.

The circuit protection apparatus and method according to an embodiment of the present invention can effectively protect a circuit from overcurrent by rapidly blowing a fuse.

In order to more fully understand the drawings recited in the Detailed Description, a detailed description of each drawing is provided.

1 is a block diagram illustrating a circuit protection device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram illustrating the overcurrent detection unit shown in FIG. 1 in more detail.

FIG. 3 is a circuit diagram illustrating the additional current generator shown in FIG. 1 in more detail.

4 is a circuit diagram illustrating the switching unit shown in FIG. 1 in more detail.

5 is a graph showing changes in current and voltage in the circuit protection device shown in FIG. 1 .

6 is a block diagram illustrating a circuit protection device according to a second embodiment of the present invention.

7 is a block diagram illustrating a circuit protection device according to a third embodiment of the present invention.

8 is a block diagram illustrating a circuit protection device according to a fourth embodiment of the present invention.

9 is a flowchart for explaining a circuit protection method according to an embodiment of the present invention.

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed in this specification are only exemplified for the purpose of explaining the embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention are It may be implemented in various forms and is not limited to the embodiments described herein.

Since the embodiments according to the concept of the present invention may have various changes and may have various forms, the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes all modifications, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first or second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one element from another element, for example, without departing from the scope of the present invention, a first element may be called a second element, and similarly The second component may also be referred to as the first component.

When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle. Other expressions describing the relationship between elements, such as "between" and "immediately between" or "neighboring to" and "directly adjacent to", etc., should be interpreted similarly.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that the described feature, number, step, operation, component, part, or a combination thereof exists, and includes one or more other features or numbers. , it is to be understood that it does not preclude the possibility of the existence or addition of steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present specification. does not

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings.

Referring to FIG. 1 , the circuit protection device 100 may include a fuse F, an overcurrent detection unit 110 , and a fusing current supply unit 130 .

The fuse F and the overcurrent detector 110 may be connected in series between the first power source Vs and the load 200 .

Specifically, the overcurrent detection unit 110 may be connected to the first power source Vs through the first node N1. The overcurrent detection unit 110 and the fuse F may be connected through the second node N2 . The fuse F may be connected to the load 200 through the third node N3 .

The overcurrent detection unit 110 detects the current If supplied from the first power source Vs to the load 200 through the fuse F, and the detected current If exceeds a predetermined reference value. When the control signal CS may be output to the fusing current supply unit 130 .

In other words, when the overcurrent is supplied to the fuse F, the overcurrent detection unit 110 may sense the overcurrent and output a control signal to the fusing current supply unit 130 .

A specific structure and operation of the overcurrent detection unit 110 will be described in more detail with reference to FIG. 2 .

Referring to FIG. 2 , the overcurrent detection unit 110 may include a shunt resistor R, a differential amplifier 111 , a comparison amplifier 113 , and a gate driver 115 .

The shunt resistor R may be connected between the first node N1 and the second node N2 .

In other words, the shunt resistor R may be connected between the first power source Vs and the fuse F.

Input terminals of the differential amplifier 111 may be connected to both ends of the shunt resistor R, and an output terminal may be connected to any one of input terminals of the comparison amplifier 113 .

The differential amplifier 111 may output the first voltage V1 corresponding to the voltage across the shunt resistor R to the comparison amplifier 113 .

Any one of the input terminals of the comparison amplifier 113 may be connected to an output terminal of the differential amplifier 111 , the other of the input terminals may be connected to a reference voltage source, and the output terminal may be connected to the gate driver 115 . can be connected to

The comparison amplifier 113 may output the second voltage V2 corresponding to the difference voltage between the first voltage V1 and the reference voltage Vref to the gate driver 115 .

The gate driver 115 may generate the control signal CS according to the polarity of the second voltage V2 .

In other words, when the first voltage (V1) is greater than the reference voltage (Vref) and the second voltage (V2) has a low voltage value, for example, 0 [V], the gate driver 115 uses the fusing current supply unit ( The control signal CS may be output to the fusing current supply unit 130 to operate 130 .

Referring back to FIG. 1 , the fusing current supply unit 130 may be connected in parallel to the overcurrent sensing unit 110 and the fuse F between the first node N1 and the third node N3 .

The fusing current supply unit 130 may supply the additional current Iblow to the fuse F in response to the control signal CS output from the overcurrent detection unit 110 .

Here, the additional current Iblow may be generated by the electric charge stored in the fusing current supply unit 130 , and the electric charge may be supplied from the second power source (Va of FIG. 3 ).

In other words, the fusing current supply unit 130 may store the charge supplied from the second power source Va, and may allow the stored charge to flow to the fuse F in response to the control signal CS.

The fusing current supply unit 130 may include an additional current generation unit 131 and a switching unit 133 .

The additional current generator 131 and the switching unit 133 may be connected in series between the first node N1 and the third node N4 .

The additional current generator 131 may be connected between the first node N1 and the fourth node N4 .

If the additional current generator 131 is able to store the charge supplied from the second power source Va, the current loop including the first node N1 to the fourth node N4 is generated by the switching unit 133 . When a current path in the form of a loop is created, an additional current (Iblow) can be supplied using the stored charge.

A specific structure and operation of the additional current generating unit 131 will be described in more detail with reference to FIG. 3 , and a specific structure and operation of the switching unit 133 will be described in more detail with reference to FIG. 4 .

Referring to FIG. 3 , the additional current generator 131 may include a second power source Va, an insulating converter 135 and a capacitor C. Referring to FIG.

According to an embodiment, the second power source Va may be an AC power source or a DC power source.

According to another embodiment, the second power source Va may be the same power source as the first power source Vs.

When the second power source Va is an AC power source, the isolation converter 135 may be configured as an AC to DC converter.

Conversely, when the second power source Va is a DC power source, the isolation converter 135 may be configured as a DC to DC converter.

The second power source Va may be implemented as an external power source or a battery.

The isolation converter 135 may convert the second power Va to be supplied to the capacitor C. In other words, the isolation converter 135 may charge the capacitor C by converting the second power Va to DC power.

The capacitor C may store the charge supplied from the isolation converter 135 .

In other words, the capacitor C stores the charge supplied by the DC power converted by the insulating converter 135 to generate a potential difference Vc between the first node N1 and the fourth node N4 .

Referring to FIG. 4 , the switching unit 133 may include a diode D and a switching element SE.

Although the diode D is illustrated in the switching unit 133 in FIG. 4 , the diode D is not essential in the switching unit 133 . That is, the diode D may be selectively included in the switching unit 133 for more improved performance.

The diode D may be connected between the third node N3 and the switching element SE.

The diode D may pass only a current flowing from the third node N3 to the fourth node N4 and block a current in the opposite direction.

In other words, the diode D allows the additional current Iblow generated by the fusing current supply unit 130 to be supplied to the first node N1 .

The switching element SE may connect the third node N3 and the third node N4 in response to the control signal CS.

In other words, the switching element SE may connect the fuse F and the additional current generator 131 in response to the control signal CS.

The gate terminal of the switching element SE is connected to the overcurrent detector 110 and may receive the control signal CS.

A source terminal of the switching element SE may be connected to the third node N3 , and a drain terminal may be connected to the fourth node N4 .

The switching device SE may include a semiconductor switching device such as an insulated gate bipolar transistor (IGBT) and a metal oxide semiconductor field effect transistor (MOSFET).

Although the switching element SE is illustrated in FIG. 4 , this is only an exemplary embodiment for convenience of description and does not limit the technical spirit of the present invention. For example, instead of one switching element SE, a plurality of IGBTs and/or a plurality of MOSFETs may be connected in series and/or in parallel.

Figure 5 (a) shows a change in the current (If) flowing through the fuse, Figure 5 (b) shows the current (Is) supplied from the first power source (Vs), Figure 5 (c) is an additional current generation It represents the voltage Vc across the capacitor C of the part 131 .

In the normal period (a), that is, when no overcurrent flows, the voltage Vc across the capacitor C may maintain a charged state.

Thereafter, in the short circuit fault section (b), the current Is supplied from the first power source (Vs) may increase. In FIG. 5 , the current Is is illustrated as a gradual increase in order to explain the operation of the circuit protection device 100 , but this is only for convenience of description, and does not simulate a current change in an actual short circuit accident.

When the current Is increases to exceed the reference current Iref, the overcurrent detection unit 110 may detect the overcurrent and output the control signal CS to the fusing current supply unit 130 .

The fusing current supply unit 130 may supply the additional current Iblow generated by the charge stored in the capacitor C to the fuse F in response to the control signal CS.

Accordingly, the current If supplied to the fuse F is the sum of the current Is supplied from the first power source and the current Iblow supplied from the circuit protection device 100 and is greatly increased in a short time to ) can accelerate the melting rate.

After the fuse is blown (C), the fuse F is blown and the current Is supplied from the first power source Vs is cut off. The additional current Iblow supplied from the supply unit 130 may also be extinguished.

In this case, the diode D may block a current that may flow from the first power source Vs to the load 200 through the circuit protection device 100 .

Referring to FIG. 6 , a plurality of circuit protection devices 100 - 1 and 100 - 2 may be implemented together in one system.

As shown in FIG. 6 , in the bidirectional DC system, a plurality of first power sources Vs-1 and Vs-2 exist, and in order to effectively protect the circuit, a plurality of circuit protection devices 100-1 and 100- 2) may be preferably provided.

Since the fuse F is shared by the plurality of circuit protection devices 100-1 and 100-2, when the fuse F is blown by any one of the plurality of circuit protection devices 100-1 and 100-2, the entire The system can be protected.

The first circuit protection device 100-1 mainly detects a current flowing from left to right in the entire system to protect the circuit, and the second circuit protection device 100-2 mainly detects a current flowing from right to left in the entire system. can be detected to protect the circuit.

Referring to FIG. 7 , a plurality of circuit protection devices 100 - 1 and 100 - 2 may be implemented in one system in a method different from that illustrated in FIG. 6 .

As shown in FIG. 7 , a plurality of circuit protection devices 100 - 1 and 100 - 2 may be completely separately provided in the bidirectional DC system.

Each of the plurality of circuit protection devices 100-1 and 100-2 detects a current flowing through each of the fuses F-1 and F-2, and when an overcurrent is detected, an additional current is applied to each of the fuses F-1 and F-2. -2) to blow each fuse (F-1, F-2) by fusion.

Since the functions, structures, and operations of the plurality of circuit protection devices 100 - 1 and 100 - 2 in FIGS. 6 and 7 are not significantly different from those of the circuit protection device 100 shown in FIG. 1 , a detailed description thereof will be omitted.

Since the circuit protection device 100 ′ of FIG. 8 and the circuit protection device 100 of FIG. 1 are substantially the same except for the connection structure of the fuse F and the

overcurrent detecting units

110 and 110 ′, the overlapping description will be omitted. do.

Referring to FIG. 8 , the fuse F and the overcurrent detecting unit 110 ′ may be connected in series between the first power source Vs and the load 200 .

Specifically, the fuse F may be connected between the first node N1 connected to the first power source Vs and the overcurrent detection unit 110', and the overcurrent detection unit 110' is the load 200. It may be connected between the third node N3 connected to and the fuse F.

As shown in FIG. 8 , even when the fuse F and the overcurrent detection unit 110 ′ are arranged, the overcurrent detection unit 110 ′ can detect the current If flowing through the fuse F, thereby protecting the circuit. (100') may operate normally.

However, in the circuit protection device 100 ′ shown in FIG. 8 , after the fuse F is blown, the overcurrent detecting unit 110 ′ is electrically connected to the third node N3 , and the third node N3 and the third node N3 The potential difference between the four nodes N4 may correspond to the magnitude of the first power source Vs.

Accordingly, a restriction condition that the common-mode voltage of the differential amplifier of the overcurrent detecting unit 110 ′ connected to the third node N3 must be greater than the first power Vs may occur.

As the common mode voltage increases, the unit cost of the device increases, so that the manufacturing cost of the circuit protection device 100 ′ may increase.

In the circuit protection device 100 shown in FIG. 1 , after the fuse F is blown, the overcurrent detecting unit 110 is electrically connected to the first node N1, and the first node N1 and the fourth node N4 ) may correspond to the potential difference Vc charged in the capacitor C.

Since the potential difference Vc charged in the capacitor C is very low compared to the first power source Vs, the common mode voltage of the differential amplifier of the overcurrent sensing unit 110 may be low.

That is, the manufacturing cost of the circuit protection device 100 illustrated in FIG. 1 may be low.

Referring to FIG. 9 , the circuit protection device 100 may store the charge supplied from the second power source Va in the capacitor C ( S100 ).

The circuit protection device 100 may detect the current If flowing through the fuse F (S200).

The circuit protection device 100 may compare the magnitude of the current If flowing through the fuse F with a predetermined value Iref ( S300 ).

If the magnitude of the current If flowing to the fuse F does not exceed the predetermined value Iref ('No' branch of S300), the circuit protection device 100 determines that the system is normal and continues the fuse F ) can sense the current (If) flowing through the

When the magnitude of the current If flowing through the fuse F exceeds the predetermined value Iref, the circuit protection device 100 , specifically, the overcurrent detection unit 110 may generate the control signal CS ( S400).

The circuit protection device 100 , specifically, the fusing current supply unit 130 may supply an additional current Iblow generated by the charge stored in the capacitor C to the fuse F in response to the control signal CS. (S500).

Although the present invention has been described with reference to an embodiment shown in the drawings, this is merely exemplary, and those of ordinary skill in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

Claims

an overcurrent detecting unit detecting a current supplied from the first power source through the fuse and outputting a control signal when the sensed current exceeds a reference value; and

and a fusing current supply unit storing an electric charge supplied from a second power source and supplying an additional current generated by the stored electric charge to the fuse in response to the control signal.
According to claim 1,

The overcurrent detection unit is a circuit protection device connected between the first power source and the fuse.
3. The method of claim 2,

The overcurrent detection unit,

a shunt resistor connected between the first power source and the fuse;

a differential amplifier outputting a first voltage corresponding to the voltage across the shunt resistor;

a comparison amplifier outputting a second voltage corresponding to a difference voltage between the first voltage and a reference voltage; and

and a gate driver outputting the control signal according to the second voltage.
According to claim 1,

The fusing current supply unit,

an additional current generator configured to store the charge supplied from the second power source; and

and a switching unit configured to generate a current loop passing through the fuse, the overcurrent detecting unit, and the additional current generating unit in response to the control signal.
5. The method of claim 4,

The additional current generator,

an isolation converter converting the second power into DC power; and

and a capacitor configured to store the electric charge supplied from the DC power supply.
5. The method of claim 4,

The switching unit,

and a switching element configured to connect the fuse and the additional current generator in response to the control signal.
7. The method of claim 6,

The switching unit,

The circuit protection device further comprising a diode connected between the fuse and the switching element.
In the circuit protection method of the circuit protection device for blocking the overcurrent flowing from the first power source to the load,

storing electric charges supplied from a second power source;

detecting a current supplied from the first power source;

generating a control signal when the magnitude of the current exceeds a predetermined value; and

and supplying the stored charge to a fuse in response to the control signal.