KR20160057079A - Over Voltage Protection Circuit for protecting Switching Element for Supplying Power - Google Patents

Over Voltage Protection Circuit for protecting Switching Element for Supplying Power Download PDF

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Publication number
KR20160057079A
KR20160057079A KR1020140157806A KR20140157806A KR20160057079A KR 20160057079 A KR20160057079 A KR 20160057079A KR 1020140157806 A KR1020140157806 A KR 1020140157806A KR 20140157806 A KR20140157806 A KR 20140157806A KR 20160057079 A KR20160057079 A KR 20160057079A
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KR
South Korea
Prior art keywords
switching element
overvoltage
zener diode
capacitor
terminal
Prior art date
Application number
KR1020140157806A
Other languages
Korean (ko)
Inventor
오필경
Original Assignee
엘에스산전 주식회사
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Application filed by 엘에스산전 주식회사 filed Critical 엘에스산전 주식회사
Priority to KR1020140157806A priority Critical patent/KR20160057079A/en
Publication of KR20160057079A publication Critical patent/KR20160057079A/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16504—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the components employed
    • G01R19/16523—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the components employed using diodes, e.g. Zener diodes
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
    • H02H7/1222—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters responsive to abnormalities in the input circuit, e.g. transients in the DC input
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage

Abstract

The present invention relates to an overvoltage protection circuit of a switching element which is provided in an inverter to convert direct current power into alternating current power, which comprises: a capacitor connected to a voltage line connected to a collector terminal of the switching element, and storing voltage applied to the voltage line; a zener diode connected to the capacitor, and conducted when overvoltage greater than or equal to setting voltage is applied thereto; and an overvoltage limiting transistor connected to the zener diode, the capacitor, and a gate terminal of the switching element, and supplying gate power to the switching element by being turned on when the zener diode is conducted.

Description

[0001] The present invention relates to an overvoltage protection circuit for a power supply switching device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overvoltage protection circuit for a switching element, and more particularly to an overvoltage protection circuit for a power supply switching element used in an industrial power conversion apparatus, To an overvoltage protection circuit of a switching element for power supply capable of protecting a switching element for power supply from an overvoltage protection circuit.

Generally, an inverter is widely used in a wide range of industries including a motor application field and various electric device fields.

The inverter converts an AC voltage to a DC voltage, switches the DC voltage according to a PWM (Pulse Width Modulation) signal to generate an AC voltage, and outputs the generated AC voltage to a load The user can precisely control the driving of the load by supplying the AC voltage of the desired voltage and frequency to the load.

On the other hand, inverters are also used in solar power generation systems. Solar power generation systems are being actively researched and developed in advanced countries as a countermeasure against global environmental problems and diversification of untapped energy sources, owing to the pollution and infinite qualities of solar energy. have.

Such a photovoltaic power generation system is classified into a stand-alone power generation system that stores generated power in a battery and supplies power at a required time according to the utilization method of the developed power, and a grid-type power generation system that supplies power to the load and supplies surplus power to the system Power generation system.

In recent years, grid-connected power generation systems have been spreading by minimizing the influence of distributed power systems, protecting system against accidents, and improving control technology of inverters.

The grid-connected power generation system includes a solar cell array unit including a plurality of solar cell strings in which a plurality of solar cell modules are connected in series, a connection unit for outputting a combined direct current power output from the solar cell strings, And an inverter that converts the output DC power into AC power and supplies the AC power to a load or a commercial system.

At this time, the inverter is composed of a plurality of switching elements for power supply, and FIG. 1 shows switching elements (hereinafter referred to as switching elements) T for power supply.

Between the gate terminal and the collector terminal of the switching element T is connected a cathode terminal of the switching element T and a diode D whose anode terminal is connected to the gate terminal of the switching element T, Thereby preventing a current from flowing from the gate side to the collector side.

A zener diode Dz is connected between the collector terminal of the switching element T and the diode D so that an overvoltage higher than a set voltage is applied to the switching element T when the switching element T is turned off. T, the Zener diode Dz is turned on to protect the switching element T by limiting the overvoltage exceeding the voltage set by the Zener diode Dz.

In the case of a solar inverter, the panel voltage rises in winter, and the bus line voltage Vdc connected to the panel also rises. If the bus voltage line Vdc becomes higher than the set zener diode voltage when the switching element T is not operating, an overcurrent flows through the control diode Dz, causing breakage of the gate driver.

Further, if the set voltage of the control diode Dz is set to be equal to or higher than the bus line voltage, the overvoltage protection function is lost.

Therefore, there is a need for a method capable of preventing breakdown of the gate driver even when the bus line voltage rises and protecting the switching element T from overvoltage when the switching element T is turned off when the switching element does not operate .

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the problems of the conventional art as described above, and it is an object of the present invention to provide a power supply switching device, To an overvoltage protection circuit of a switching element for power supply capable of protecting a switching element for power supply from an overvoltage caused by overvoltage.

According to an aspect of the present invention, there is provided an overvoltage protection circuit for a switching device, the overvoltage protection circuit for switching a power supply switching device according to an embodiment of the present invention, A capacitor connected to a voltage line connected to a collector terminal of the switching element and storing a voltage applied to the voltage line; A zener diode connected to the capacitor and rendered conductive when an overvoltage equal to or higher than a set voltage is applied; And an overvoltage limiting transistor connected to the gate terminals of the zener diode, the capacitor and the switching element and turned on when the control diode is conductive to supply gate power to the switching element.

At this time, one end of the capacitor is connected to the voltage line connected to the collector terminal of the switching element, the other end of the capacitor is connected to the cathode of the Zener diode, and the anode of the Zener diode is connected to the base terminal The base of the transistor is connected to the anode of the Zener diode and the collector terminal of the transistor for limiting the overvoltage is connected to one end of the capacitor and the other end of the capacitor is connected to the anode of the Zener diode, And an emitter terminal of the overvoltage limiting transistor is connected to the gate terminal of the switching element.

The overvoltage protection circuit according to the present invention further includes a voltage dividing resistor having one end connected to the base terminal of the overvoltage limiting transistor and the other end connected to the anode of the zener diode.

The overvoltage protection circuit according to the present invention further includes a driving transistor having a drain terminal connected to the other end of the capacitor, a source terminal connected to the base terminal of the overvoltage limiting transistor, and a gate terminal connected to the anode of the Zener diode do.

On the other hand, the overvoltage limiting transistor is turned on when the Zener diode is turned on, thereby connecting the capacitor and the gate terminal of the switching element.

Further, the driving transistor is turned on when the Zener diode is conductive, and connects the capacitor and the base terminal of the transistor for limiting the overvoltage.

According to the above-described configuration of the overvoltage protection circuit of the switching element for power supply according to the present invention, when the switching element is turned off or turned off, the voltage applied to the voltage line due to the temperature rise of the voltage line, It is possible to prevent the overvoltage from being applied to the switching element.

Therefore, it is possible to prevent the switching element from being damaged by the overvoltage, and also to prevent damage to the gate driver which applies the gate signal to the switching element.

1 is a configuration diagram showing an example of an overvoltage protection circuit of a switching element for power supply according to the prior art.
2 is a configuration diagram of a system including a power conversion apparatus to which an overvoltage protection circuit of a switching element for power supply according to an embodiment of the present invention is applied.
3 is a configuration diagram of an overvoltage protection circuit of a switching element for power supply according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. Further, terms to be described below are terms defined in consideration of functions in the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

FIG. 2 is a configuration diagram of a system including a power conversion apparatus to which an overvoltage protection circuit of a switching element for power supply according to an embodiment of the present invention is applied. FIG. 3 is a schematic diagram of an overvoltage Fig.

At this time, the system S may be a solar power generation system, and 100 may be a solar cell as a power supply source, but the present invention is not limited thereto, and the overvoltage protection It goes without saying that the circuit can be widely used in various fields of power conversion apparatuses.

Referring again to FIG. 2, reference numeral 200 denotes a power conversion apparatus which receives DC power from a power supply source 100, converts the AC power into AC power, and supplies the AC power to the load 400 or the system 500.

Reference numeral 300 denotes a gate driver for applying a switching signal to the power converter 200 to control the switching operation of the power converter 200.

The power conversion device 200 includes a plurality of switching devices T1 to T4 that operate in accordance with a switching signal of the gate driver 300 and may further include a plurality of switching devices T1 to T4, And overvoltage protection circuits 210 to 240 for protection against overvoltage.

Since the configuration of the overvoltage protection circuits 210 to 240 connected to the plurality of switching devices T1 to T4 is the same as that of the overvoltage protection circuit 210 connected to the switching device T1, The overvoltage protection circuit according to the embodiment of the present invention will be described in detail. The switch element shall be described as "T".

3, the overvoltage protection circuit 210 according to the embodiment of the present invention is disposed between the gate terminal and the collector terminal of the switching element T so that when the switching element T is turned off or turned off When the voltage Vdc applied to the voltage line L connected to the collector terminal C of the switching element T is an overvoltage in a state in which the switching element T and the gate driver 300 are damaged .

Specifically, the overvoltage protection circuit 210 according to the embodiment of the present invention includes a capacitor C, a zener diode Dz, and a transistor Q for limiting overvoltage.

The capacitor C is connected to a voltage line L whose one end is connected to the collector terminal C of the switching element T and the other end is connected to the cathode of the Zener diode Dz.

The anode of the Zener diode Dz is connected to the base terminal B of the overvoltage limiting transistor Q and the cathode of the Zener diode Dz is connected to the other end of the capacitor C .

The overvoltage limiting transistor Q has a base terminal B connected to the anode of the Zener diode Dz and a collector terminal C connected between the one end of the capacitor C and the voltage line L, And the gate terminal (E) is connected to the gate terminal (G) of the switching element (T).

The voltage Vdc applied to the voltage line L is applied to the one end of the capacitor C and the collector terminal C of the overvoltage limiting transistor Q so that the capacitor C is charged with the applied voltage Vdc, .

At this time, when the voltage Vdc applied to the voltage line L is an overvoltage greater than the set voltage of the Zener diode Dz, the Zener diode Dz is turned on and a current flows through the Zener diode Dz, Is connected to the base terminal B of the overvoltage limiting transistor Q and the overvoltage limiting transistor Q is turned on so that one end of the capacitor C and the gate terminal G of the switching element T are connected do.

Therefore, when an overvoltage is applied to the zener diode Dz, the overvoltage limiting transistor Q is turned on.

At this time, when the overvoltage limiting transistor Q is turned on, one end of the capacitor C is connected to the gate terminal G of the switching element T, so that the gate terminal G of the switching element T The charging voltage of the capacitor C is applied.

On the other hand, when the current flowing through the Zener diode Dz is directly applied to the base terminal B of the overvoltage limiting transistor Q, the overvoltage limiting transistor Q may be damaged, And a voltage dividing resistor Rs connected to the base terminal B of the overvoltage limiting transistor Q and the other end connected to the anode of the Zener diode Dz.

In the overvoltage protection circuit 210, the drain terminal D is connected to the other end of the capacitor C, the source terminal S is connected to the base terminal B of the overvoltage limiting transistor Q, And a driving transistor M to which a gate terminal G is connected to the anode of the diode Dz.

At this time, the gate terminal G of the driving transistor M is connected between the zener diode Dz and the voltage-dividing resistor Rs. Specifically, the gate terminal G of the driving transistor M is connected between the anode terminal of the zener diode Dz and the other terminal Respectively.

The driving transistor M is turned on when a current flowing through the zener diode Dz is applied to the gate terminal G and is turned on when the transistor Q is turned on and the transistor Q for limiting the overvoltage of the other terminal of the capacitor C is turned on. To the base terminal (B). Therefore, the operation of the limiting transistor Q is stably performed because it is not affected by the zener diode Dz and the divided voltage Rs.

According to the above-described configuration of the overvoltage protection circuit of the switching element for power supply according to the present invention, when the switching element is turned off or turned off, the voltage applied to the voltage line due to the temperature rise of the voltage line, The overvoltage is not applied to the switching element, so that the switching element is prevented from being damaged due to the overvoltage. In this case, since the overvoltage limiting transistor is turned on by connecting the zener diode to the gate terminal of the switching element, And the damage of the gate driver can be prevented.

While the present invention has been described in connection with certain exemplary embodiments thereof, it is to be understood that the invention is not limited to the specific embodiments thereof, And various modifications, alterations, and changes may be made without departing from the spirit and scope of the invention.

Therefore, the embodiments described in the present invention and the accompanying drawings are intended to illustrate rather than limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and accompanying drawings . The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

100: power source 200: power converter
210, 220, 230, 240: Overvoltage protection circuit 300: Gate driver
400: load 500: system
C: Capacitor Dz: Zener diode
M: driving transistor Q: over-voltage limiting transistor
Rs: voltage divider resistance T: switching element

Claims (6)

An overvoltage protection circuit of a switching element provided in an inverter and switched to convert DC power into AC power,
A capacitor connected to a voltage line connected to a collector terminal of the switching element and storing a voltage applied to the voltage line;
A zener diode connected to the capacitor and rendered conductive when an overvoltage equal to or higher than a set voltage is applied; And
And an overvoltage limiting transistor connected to the gate terminal of the Zener diode, the capacitor, and the switching element and turned on when the control diode is turned on to supply gate power to the switching element, Protection circuit. The method according to claim 1,
One end of the capacitor is connected to a voltage line connected to the collector terminal of the switching element, the other end of the capacitor is connected to the cathode of the zener diode,
The anode of the Zener diode is connected to the base terminal of the transistor for limiting the overvoltage, the cathode of the Zener diode is connected to the other end of the capacitor,
The base terminal of the overvoltage limiting transistor is connected to the anode of the Zener diode, the collector terminal of the overvoltage limiting transistor is connected between the one end of the capacitor and the voltage line, and the emitter terminal of the overvoltage limiting transistor And the overvoltage protection circuit of the switching element for power supply connected to the gate terminal of the switching element. 3. The method of claim 2,
And a voltage dividing resistor having one end connected to the base terminal of the overvoltage limiting transistor and the other end connected to the anode of the zener diode. 3. The method of claim 2,
And a drive transistor having a drain terminal connected to the other end of the capacitor, a source terminal connected to the base terminal of the overvoltage limiting transistor, and a gate terminal connected to the anode of the Zener diode. Protection circuit. The method according to claim 1,
Wherein the overvoltage limiting transistor is turned on when the Zener diode is conductive and connects the capacitor and the gate terminal of the switching element. 5. The method of claim 4,
Wherein the drive transistor is turned on when the Zener diode is conductive and connects the capacitor and the base terminal of the transistor for limiting the overvoltage.
KR1020140157806A 2014-11-13 2014-11-13 Over Voltage Protection Circuit for protecting Switching Element for Supplying Power KR20160057079A (en)

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KR1020140157806A KR20160057079A (en) 2014-11-13 2014-11-13 Over Voltage Protection Circuit for protecting Switching Element for Supplying Power

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KR1020140157806A KR20160057079A (en) 2014-11-13 2014-11-13 Over Voltage Protection Circuit for protecting Switching Element for Supplying Power

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018147539A1 (en) * 2017-02-13 2018-08-16 주식회사 마루온 Heat generation and spark reduction switch circuit
KR20190028929A (en) * 2017-09-11 2019-03-20 엘지이노텍 주식회사 LED module control device
KR20210079492A (en) * 2019-12-19 2021-06-30 한국철도기술연구원 Over voltage protection circuit for protecting power semiconductor switching device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018147539A1 (en) * 2017-02-13 2018-08-16 주식회사 마루온 Heat generation and spark reduction switch circuit
KR20190028929A (en) * 2017-09-11 2019-03-20 엘지이노텍 주식회사 LED module control device
KR20210079492A (en) * 2019-12-19 2021-06-30 한국철도기술연구원 Over voltage protection circuit for protecting power semiconductor switching device

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