KR20210095471A - Detection apparatus for leakage current fault of LED lighting using earth resistance - Google Patents

Abstract

The present invention relates to an LED light leakage detection device using earth resistance. When it is assumed that a terminal of a DC voltage line through which a DC voltage output from an SMPS flows is a terminal a, an enclosure terminal of a luminaire is a terminal b, and a neutral terminal, which is a terminal of a neutral wire connected to the SMPS, is a terminal c, the LED light leakage detection device includes a contact resistance (R_L) for a contact and a connection accident as a resistance component located between the terminals a and b; and an earth resistance (R_g) between the ground of the AC power supply unit and the ground of the LED module unit as a resistance component located between the terminals b and c. The LED light leakage detection device measures the magnitude of a leakage current that is inversely proportional to the contact resistance (R_L) and flows through the earth resistance (R_g), thereby outputting a leakage current detection signal. According to the present invention, by detecting the leakage voltage using the earth resistance between the ground and the leakage point contact resistance, it is possible to more accurately and quickly detect and prevent a leakage accident of the LED lighting.

Description

{Detection apparatus for leakage current fault of LED lighting using earth resistance}

The present invention relates to a technology for detecting an electric leakage accident of an LED lighting, and more particularly, to a technology for detecting an electric leakage of an LED lighting using an earth resistance.

Recently, the government and each local government are actively installing LED lights to create urban landscapes such as streets, parks, beaches, and roadsides where many people travel as a paradigm of urban environment improvement. Specifically, the government is focusing on the development and distribution of eco-friendly energy for efficient use of energy and reduction of environmental pollution. is being actively pursued.

In addition, each local government is actively promoting the creation of urban landscapes such as streets, parks, beaches, and roadside areas frequented by many people as a paradigm of urban environment improvement. Various kinds of lighting are essential to the creation of various landscapes, and the use of LED lighting is implemented as a national policy in terms of energy consumption efficiency.

These LED lights have recently been installed in many places so that they can be seen anywhere, of course. These LED lights, along with colorful lighting, are creating an excellent landscape effect above all because they dazzle and agitate the people watching by lighting control.

However, despite the splendor of these LED lights, the construction company and the management body are indifferent to safety accidents, and it is true that users and spectators are also indifferent to safety issues.

In particular, it can be said that LED landscape lighting is very concerned about electric leakage accidents related to human damage due to the fact that there are many connection lines between lighting lamps and the electric lines (converters) are long. Technically, since LED lighting equipment uses direct current (DC) power, verification of electrical safety in the secondary DC circuit of SMPS (switching mode power supply) is required.

Moreover, in the case of non-insulated SMPS, it is widely used due to its small size, light weight, and low cost, but a safety device against an electric leakage accident is essential.

However, research and technology development for the cause analysis and prevention of electric fires, short circuits, and electric shock accidents in electrical equipment and products so far have been mainly conducted based on AC power, and There is very little research on it.

Republic of Korea Patent 10-0804520

The present invention has been devised to solve the above problems, and in order to detect and prevent leakage accidents of LED lighting, etc., it is not a current detection method of detecting a leakage current, but a ground resistance between ground and a leakage point contact resistance. The purpose of this is to propose a circuit topology that prevents leakage accidents by detecting the leakage voltage used.

Objects of the present invention are not limited to the objects mentioned above, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention for achieving the above object is an AC power supply for supplying AC power, a switching mode power supply (SMPS) for converting AC power supplied from the AC power supply into DC power, and a DC power output from the SMPS. In the LED light leakage detection device for detecting an electric leakage of an LED lighting lamp composed of an LED module unit including a luminaire driven by When the enclosure terminal of the terminal is the b terminal, and the neutral wire terminal, which is the terminal of the neutral wire connected to the SMPS, is the c terminal, as a resistance component located between the a terminal and the b terminal, the contact resistance against contact and connection accidents (R _L ) _{and a resistance component positioned between the b terminal and the c terminal, including a ground resistance (R g} ) between the ground of the AC power supply unit and the ground of the LED module unit, and is inversely proportional to the size of the contact resistance (R _{L )} and measuring the magnitude of the leakage current, which is the current flowing through the earth resistance (R _g ), and if the magnitude of the leakage current exceeds a preset reference value, it is determined as a leakage current and outputs a leakage detection signal.

In the present invention, a first resistor (R _a ) having one side connected to the a terminal, one side connected to the other side of the first resistor (R _{a ), and a second resistor (R b} ) having the other side connected to the b terminal _{, a third resistor R c} having one end connected to the a terminal, one end connected to the other side of the third resistor R _{c , and a fourth resistor R d} having the other end connected to the c terminal, and the A first connection point 1' between _a first resistor R a and a second resistor R _b and a second connection point 2' between _{the third resistor R c} and a fourth resistor R _{d .} It may further include a measurement amplifier for measuring the leakage current by amplifying the voltage between the two.

The instrumentation amplifier may be implemented as an operational amplifier having a non-inverting terminal connected to the first connection point 1' and an inverting terminal connected to the second connection point 2'.

The earth resistance (R _g ), the first resistance (R _a ), the second resistance (R _b ), the third resistance (R _c ), and the fourth resistance (R _d ) are, ① R _a = R _{c ,} ② When R _d = R _b + R _{g ,} ③ R _a ≫ R _{b ,} ④ R _c ≫ R _d is set, if the output voltage of the op amp is 0 or negative (-) voltage value, the normal state is displayed, If the voltage value is (+), it can be indicated as a short circuit fault.

According to the present invention, by detecting the leakage voltage using the earth resistance between the ground and the leakage point contact resistance, there is an effect that can more accurately and quickly detect and prevent an electric leakage accident such as LED lighting.

In addition, according to the present invention, each resistive element is constituted by a Wheatstone bridge circuit, and by using an amplifier for measurement, there is an effect that reliability and quick response are excellent in detecting an electric leakage fault.

In addition, the leakage voltage detection type earth leakage detection circuit proposed in the present invention is a technique for detecting voltage according to the magnitudes of earth resistance and contact resistance. It has the advantage that it solves the problem of blackout accidents caused by malfunctions or malfunctions of earth leakage breaker due to capacitive leakage current.

1 is a schematic diagram of a power circuit of an LED lighting lamp.
2 is an equivalent circuit diagram in the case of an electric leakage accident in the LED lighting lamp.
3 is a circuit diagram of a leakage voltage detection type leakage detection device of an LED lighting lamp proposed in the present invention.
4 is an example of an experimental apparatus of a leakage detection circuit of an LED lighting lamp according to an embodiment of the present invention.
5 is a table showing the integer values of elements used in the configuration of the experimental circuit of the LED light leakage detection circuit according to an embodiment of the present invention.
6 to 9 are waveform diagrams showing the operating characteristics of the leakage detection circuit of the LED lighting lamp according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

The terms used in the present application are only used 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 application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, 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 application. does not

In addition, in the description with reference to the accompanying drawings, the same components are assigned the same reference numerals regardless of the reference numerals, and the overlapping description thereof will be omitted. In describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a schematic diagram of a power circuit of an LED lighting lamp, and shows a schematic diagram of a power circuit of an LED lighting lamp driven by a non-insulated SMPS.

The circuit configuration in FIG. 1 is as follows.

SMPS (switching mode power supply) 20 converts AC 220V, 60Hz AC power output from the AC power supply unit 10 into DC power of about DC 5V to 48V to supply power to the LED module unit 30 . Then, the AC power supply unit 10 and a part of the light fixture are grounded to the ground 40 composed of a third type ground of 100 Ω or less.

Here, H is the voltage line of the AC power supply, N is the neutral line, G is the ground line, and H' is the DC voltage line.

2 is an equivalent circuit diagram in the case of an electric leakage accident in an LED lighting lamp.

In FIG. 2, the resistance R _L means the contact resistance against the contact and connection accidents between the DC voltage line of the SMPS 20 and the LED luminaire enclosure, and the size of the leakage current I _g is determined _{according to the size of the contact resistance R L .} Here, the size of the leakage current I _g is regulated as 30 mA or less according to the technical standards for electrical equipment.

And, the resistance R _g represents the earth resistance between the ground of the AC power supply unit 10 and the ground of the LED luminaire. In the case of LED lighting, the size of the earth (ground) resistance is set to 100Ω or less by stipulating the 3rd type grounding.

3 is a circuit diagram of a leakage voltage detection type leakage detection device of an LED lighting lamp proposed in the present invention. 3 shows a leakage voltage detection circuit diagram of an LED lighting lamp using the earth resistance (R _g ) and the leakage point contact resistance (R _{L ) proposed in the present invention.}

The circuit configuration in FIG. 3 is as follows.

The DC voltage (V _dc ) output from the SMPS 20 is supplied to the LED module unit 30 . Typically, the voltage supplied to the LED module unit 30 is DC 5V to 48V.

_{And, the contact resistance R L} , the earth resistance R _{g between the ground, and the resistors R a} and R _b are connected to the terminal a of the DC voltage line and the terminal b of the luminaire enclosure, which appear when a short circuit accident occurs in the LED lighting, and the terminal a and the DC voltage _{Resistors R c} and R _d are connected to the neutral terminal c.

Then, _a Wheatstone bridge circuit using the voltage difference between the connection point 1' of the resistors R a and R _{b and} the connection point 2' of the resistors R _c and R _{d is designed.}

In addition, in order to increase the precision of the leak detection circuit proposed in the present invention, a measurement amplifier 310 is connected to the terminals 1' and 2', and serves to amplify the fine voltage at both ends of the Wheatstone bridge.

In the present invention, the measurement amplifier 310 may be composed of a plurality of operational amplifiers, and since the common mode rejection ratio (CMRR) is theoretically infinite (∞), various noise components generated in the ground If they are introduced, they are removed.

The range of integer values of the main elements used in the earth leakage detection circuit topology proposed in the present invention can be summarized as follows.

① R _a = R _c

② R _d = R _b + R _g (maximum value 100Ω)

③ R _a ≫ R _b

④ R _c ≫ R _d

⑤ {V _dc / (R _a +R _b )} ≪ 30mA

In addition, in the present invention, an integer value of each resistor may be set to operate at a DC offset current of 25 mA to 30 mA using the measurement amplifier 310 .

Looking at the operating principle of the leakage voltage detection type earth leakage detection circuit of the LED lighting lamp proposed in the present invention, if there is no earth leakage accident first _{, there is no contact resistance R L} , so the bridge is balanced and the voltage difference between terminals 1' and 2' is Since it does not occur, the output voltage V _out of the measurement amplifier 310 becomes 0V.

Here, if the earth resistance R _g is 100 Ω or less, the voltage of terminal 2' appears higher than the voltage of terminal 1', so the output voltage V _out of the measurement amplifier 310 is output as a negative voltage value to obtain a steady state. indicate

And, when an electric leakage accident occurs, the bridge becomes unbalanced due to the _{contact resistance R L , and since R a} ≫ R _b (at least 10 times or more), the voltage at terminal 1' becomes greater than the voltage at terminal 2', resulting in a measurement amplifier _{The output voltage V out} of ( 310 ) is output as a positive (+) voltage value, and indicates an earth leakage fault state.

In addition, in the earth leakage detection circuit of the present invention, if the earth resistance R _g is 100 Ω or more in a steady state without earth leakage accident, the voltage at terminal 1' becomes greater than the voltage at terminal 2' like the earth leakage accident, so that the amplifier output voltage is positive (+). be the value In this case, if it is designed to indicate a faulty state of the earth resistance, the earth leakage detection circuit of the present invention can also detect whether the earth resistance is faulty.

The contents of the LED light leakage detection device of the present invention are summarized as follows.

The LED light leakage detection device of the present invention includes an AC power supply unit 10 for supplying AC power, a switching mode power supply (SMPS) 20 and SMPS for converting AC power supplied from the AC power supply unit 10 into DC power. It is a device for detecting a short circuit of an LED lighting lamp composed of an LED module unit 30 including a luminaire driven by a DC power output from ( 20 ).

The DC voltage line terminal, which is the terminal of the DC voltage line (H') through which the DC voltage output from the SMPS 20 flows, is the terminal a, the enclosure terminal of the light fixture is the terminal b, and the neutral wire terminal is the terminal of the neutral wire (N) connected to the SMPS (20). When the c terminal, the configuration of the LED light leakage detection device of the present invention is as follows.

The LED light leakage detection device of the present invention is a resistance component located between the a terminal and the b terminal, contact resistance against contact and connection accidents (R _L ), as a resistance component located between the b terminal and the c terminal, the AC power supply unit 10 _{) and a ground resistance (R g} ) between the ground of the LED module unit 30 and the ground.

At this time, the size of the leakage current, which is inversely proportional to the size of the _{contact resistance (R L ) and flowing through the earth resistance (R g ), is measured.} print out

And, the LED light leakage detecting device of the present invention has a first resistor (R _a ) having one side connected to the a terminal, one side connected to the other side of the first resistor (R _a ), and the second side connected to the b terminal A resistor (R _{b ), a third resistor (R c} ) having one end connected to the a terminal, one end connected to the other side of the third resistor (R _c ), and a fourth resistor (R _d ) having the other end connected to the c terminal and a first connection point 1 ′ between the first resistor R _a and the second resistor R _b , and a second connection point 2 ′ between the third resistor R _c and the fourth resistor R _d . A measurement amplifier 310 is provided for measuring the leakage current by amplifying the voltage between them.

In an embodiment of the present invention, the instrumentation amplifier 310 has a non-inverting terminal (+) connected to the first connection point (1') and an inverting terminal (-) connected to the second connection point (2'). can be implemented as

In the present invention, the earth resistance (R _g ), the first resistance (R _a ), the second resistance (R _b ), the third resistance (R _c ), and the fourth resistance (R _d ) are, ① R _a = R _{c ,} ② R _d = R _b + R _{g ,} ③ When R _a ≫ R _{b ,} ④ R _c ≫ R _d is set, if the output voltage of the op amp is 0 or negative (-) voltage, it is displayed as normal, If it is a positive (+) voltage value, it can be indicated as an earth leakage fault.

An experiment was conducted to analyze the operating characteristics of the leakage voltage detection type earth leakage detection circuit for LED lighting using the earth resistance proposed in the present invention and to verify the practicality.

4 is an example of an experimental apparatus of a leakage detection circuit of an LED lighting lamp according to an embodiment of the present invention.

The configuration of the experimental apparatus in FIG. 4 is as follows.

LED lighting (DC 24V, 36W) and non-insulated SMPS (DC 24V, 2.5A, 60W) are used, and a semi-fixed variable resistor (0~5kΩ) is connected to the DC voltage line and the ground line to create a random contact resistance and short circuit. An accident occurred, and the ground (ground) resistance was connected to the ground line using a semi-fixed variable resistance (0~1kΩ).

And in order to accurately check the time of leakage detection when an earth leakage accident occurs, an Arduino microcomputer is connected to the output terminal of the measuring amplifier to display a digital output value (approximately DC 5V).

5 is a table showing integer values of elements used in the configuration of the experimental circuit of the LED light leakage detection circuit according to an embodiment of the present invention.

As shown in Fig. 5, the integer values of the elements used in the leakage detection circuit of the LED lighting lamp proposed in the present invention were designed.

6 to 9 are waveform diagrams showing the operating characteristics of the leakage detection circuit of the LED lighting lamp according to an embodiment of the present invention.

6 to 9 show operation characteristic waveforms for the occurrence of an electric leakage accident of the electric leakage detection circuit of the LED lighting lamp proposed in the present invention.

6 shows a case where the leakage current is 20 mA, and it can be confirmed that the proposed leakage current detection circuit shows the operating performance of maintaining a steady state when the leakage current is 30 mA or less according to the regulations.

7 shows the operation characteristic waveform of the earth leakage detection circuit when the leakage current is 30 mA, FIG. 8 shows the leakage current of 35 mA, and FIG. 9 shows the leakage current when the leakage current is 40 mA.

As shown in FIGS. 7 to 9, when the leakage current is 30 mA or more, it can be confirmed that the earth leakage detection circuit proposed in the present invention detects an earth leakage accident and shows good operation response performance of sending an output signal to the microcomputer.

Although the present invention has been described above using several preferred embodiments, these examples are illustrative and not restrictive. Those of ordinary skill in the art to which the present invention pertains will understand that various changes and modifications can be made without departing from the spirit of the present invention and the scope of the appended claims.

10 AC power supply 20 SMPS
30 LED module part

Claims (4)

An LED module unit including an AC power supply for supplying AC power, a switching mode power supply (SMPS) for converting AC power supplied from the AC power supply into DC power, and a luminaire driven by DC power output from the SMPS. In the LED light leakage detection device for detecting a short circuit of the configured LED light,
When the terminal of the DC voltage line, which is the terminal of the DC voltage line through which the DC voltage output from the SMPS flows, is terminal a, the enclosure terminal of the light fixture is terminal b, and the neutral terminal that is the terminal of the neutral wire connected to the SMPS is terminal c,
As a resistance component located between the a terminal and the b terminal, contact resistance (R _L ) against contact and connection accidents; and
As a resistance component located between the b terminal and the c terminal, it comprises a ground resistance (R _g ) between the ground of the AC power supply unit and the ground of the LED module unit,
By measuring the magnitude of the leakage current that is inversely proportional to the size of the contact resistance (R _{L ) and flowing through the earth resistance (R g} ), if the magnitude of the leakage current exceeds a preset reference value, it is determined as an electrical leakage and a leakage detection signal LED light leakage detection device, characterized in that the output.
The method according to claim 1,
a first resistor having one side connected to the a terminal (R _a );
_{a second resistor (R b} ) having one end connected to the other side of the first resistor (R _{a ) and the other end connected to the terminal b;}
a third resistor having one side connected to the a terminal (R _c );
_{a fourth resistor (R d} ) having one end connected to the other end of the third resistor (R _c ) and the other end connected to the c terminal; and
A first connection point 1' between the first resistor R _a and a second resistor R _b and a second connection point 2' between _{the third resistor R c} and a fourth resistor R _{d .} ) by amplifying the voltage between the LED light leakage detection device, characterized in that it further comprises a measuring amplifier for measuring the leakage current.

3. The method according to claim 2,
The instrumentation amplifier is an LED light leakage detecting device, characterized in that the non-inverting terminal is connected to the first connection point (1') and the inverting terminal is implemented as an operational amplifier connected to the second connection point (2').
4. The method according to claim 3,
The earth resistance (R _g ), the first resistance (R _a ), the second resistance (R _b ), the third resistance (R _c ), the fourth resistance (R _d ),
① R _a = R _{c ,} ② R _d = R _b + R _{g ,} ③ When R _a ≫ R _{b ,} ④ R _c ≫ R _d is set,
If the output voltage of the OP amp is 0 or a negative (-) voltage value, it is displayed as a normal state, and if it is a positive (+) voltage value, it is displayed as an electric leakage fault.

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