CN102751969B - Output short-circuit protection circuit and method of low-power photovoltaic controller - Google Patents
Output short-circuit protection circuit and method of low-power photovoltaic controller Download PDFInfo
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- CN102751969B CN102751969B CN201210239642.8A CN201210239642A CN102751969B CN 102751969 B CN102751969 B CN 102751969B CN 201210239642 A CN201210239642 A CN 201210239642A CN 102751969 B CN102751969 B CN 102751969B
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- 238000000034 method Methods 0.000 title claims description 9
- 238000005070 sampling Methods 0.000 claims abstract description 17
- 238000001514 detection method Methods 0.000 claims abstract description 7
- 239000003990 capacitor Substances 0.000 claims description 13
- 239000004065 semiconductor Substances 0.000 claims 1
- 238000001914 filtration Methods 0.000 abstract description 2
- 230000001681 protective effect Effects 0.000 description 8
- 238000010276 construction Methods 0.000 description 1
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- 238000010586 diagram Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
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Abstract
The invention relates to the technical field of direct current power supply protection, and in particular relates to a direct-current output short-circuit protection circuit of a low-power photovoltaic system. A storage battery inputs direct current into an inductor and follow-current unit consisting of a D1, an L1 and a C1 through a DC+ and a DC-; a current detection and control unit consists of a Q1, an R1, an R3, an R5, an R6, a D2 and a Q2; an overload current signal sampling filtering circuit consists of an R4 and a C3. The certain voltage is generated through a current sampling resistor of the R3, the Vi is further smaller than the Vbe of the triode Q2 during regular operation, current flowing through the resistors R2 and R3 is emergently increased when the short circuit is output, the triode Q2 is switched on when the Vi is larger than Vbe, the voltage of a Q2 collection electrode is dropped to 0V, the diode D2 is switched on, the voltage of a grid of the switch tube Q1 is dropped to approximate to zero, and the current I of a circuit is limited to be equal to Vbe/R3. The output short-circuit protection circuit disclosed by the invention has the advantages of simple structure, small volume, easiness for implementation, and safe and reliable protection performance.
Description
[technical field]
The present invention relates to DC power supply protection system technical field, specifically a kind of protective circuit of low-power photovoltaic controller output short-circuit and method thereof.
[background technology]
In order to solve the problem of the aspect such as energy shortage and ecological deterioration, the majority state comprising China is all greatly developing photovoltaic generating system, using photovoltaic generating system as main energy sources in future.
Photovoltaic generating system, because intelligent grid, power delivery circuit construction cost are huge, progressively turn to as small-sized photovoltaic home system at present, cell power controls at 20Wp-500Wp, and photovoltaic generating system and LED illumination, DC power-supply system, progressively become development trend, the i.e. direct current that sends of photovoltaic, be stored in DC energy storage unit, and by DC distribution, directly supply direct current power directly to the equipment such as LED, DC fan.
In small-sized photovoltaic home system; general is all directly be supplied to each power consumption equipment by photovoltaic charge/discharge controller; output short-circuit is not generally all protected or adopted air switch, fuse, recovers fuse soon; also the scheme adopting output current sampling to close output loop is had; existing all schemes; all unreliable, very easily damage output switch circuit.How solving photovoltaic controller output short-circuit problem, is the difficult problem that current all producers all face.
[summary of the invention]
The object of the invention is to the problem solving existing photovoltaic controller output short-circuit, the protective circuit that a kind of structure is simple, protective value is stable is provided.
For achieving the above object, design a kind of output short-circuit protection circuit of low-power photovoltaic controller, it is characterized in that the anode DC+ of DC power supply connects tap one end of inductance L 1 and diode D1 negative pole, inductance L 1 other end connects electrochemical capacitor C1 positive pole, and tap one end is DC output end OUT+, diode D1 positive pole one end connects with electrochemical capacitor C1 negative pole and tap one end is DC output end OUT-, between diode D1 positive pole and electrochemical capacitor C1 negative pole, tap connecting valve pipe Q1 drains, the phase of switching tube Q1 extremely on be connected to resistance R1 one end, and tap one end connects diode D2 positive pole, the resistance R1 other end is provided with control signal test point, switching tube Q1 source electrode is provided with current sampling resistor R3, the current sampling resistor R3 other end connects the negative terminal DC-of DC power supply and ground connection, two tap lines are provided with at resistance R3 and switching tube Q1 source electrode, first tap line is connected to resistance R4 one end, the resistance R4 other end connects electric capacity C3 one end and tap is current detection signal point, electric capacity C3 other end connecting triode Q2 emitter ground connection, second tap line contact resistance R5 one end, resistance R5 other end connecting triode Q2 base stage, diode D2 negative pole connecting triode Q2 collector electrode tap one end contact resistance R6, the resistance R6 other end is power detection signal point, by this circuit restriction output loop maximum current, improve the protective value of photovoltaic charge controller.
Direct-flow input end is storage battery, by DC+, DC-direct current is input to the inductance and afterflow element circuit that are made up of diode D1, inductance L 1, electrochemical capacitor C1; The current detecting of switching tube Q1, resistance R1, R3, R5, R6, diode D2, triode Q2 composition and control unit; Resistance R4, electric capacity C3 go in overload current signal sampling filter circuit.
During work, export the load current of DC loop, by current sampling resistor R3, create certain voltage, Ui=I*R, make Ui when normally working much smaller than the Ube of triode Q2, Ube is generally about 0.7V.When output has short circuit; the electric current flow through on resistance R3 sharply increases; Ui is then made to increase fast; as Ui>Ube; triode Q2 conducting; then the voltage drop of triode Q2 collector electrode is to about 0 volt; now diode D2 conducting; and the grid voltage of switching tube Q1 is pulled down to close to 0V; switching tube Q1 power releases saturation conduction, makes loop current be limited in I=Ube/R3, thus protects Q1; the grid voltage of switching tube Q1 is pulled down to close to 0V, and switching tube Q1 should block.
The control method of inductance and afterflow element circuit is for occurring when short circuit phenomenon, the electric current of controlling load circuit increases fast, for the conducting of triode Q2, defencive function gains time, make before triode Q2 action, switching tube Q1 is not burned, because the electric current on inductance can not specially become, induced voltage equation on inductance is: UL=L (di/dt), when switching tube Q1 conducting, when there is output short-circuit, loop current should be (Uin-UL)/R3, by separating the differential equation, electric current in very short time when short circuit increases according to indicial response, inductance is larger, it is slower that electric current increases, because the ability of controlling electric current of inductance L 1, for triode Q2, switching tube Q1 protection act has won the time, make protection reliable and stable.
The present invention compared with prior art; utilize inductance larger; electric current increases characteristic more slowly and controls electric current in output loop; protection switch unit, utilizes current detecting and control unit to detect the electric current in switch element, sample, and reacts on switch element; with the power device in protection switch unit; and buffer time is provided, guarantee that, before overload protecting circuit action, switch element is not damaged.This protective circuit structure is simple, volume is little, easy to implement, and protective value is safe and reliable.
[accompanying drawing explanation]
Fig. 1 is electrical schematic diagram of the present invention;
Fig. 2 is schematic flow sheet of the present invention;
[embodiment]
Below in conjunction with accompanying drawing, the present invention is further elaborated, and its structure and method can realize for a person skilled in the art.
As shown in Figure 1, circuit is made up of direct current component, inductance and afterflow unit, current detecting and control unit, overload current signal sampling filter circuit and switch element six part the principle of the invention.Direct current component refers to charge circuit, storage battery etc., is used for charging and stored energy; There are the components and parts such as inductance, electric capacity, diode in inductance and afterflow unit, are used for smothing filtering and when output loop has short circuit to occur, suppress the electric current of output loop to increase fast, the device for power switching in protection switch unit; Switch element is device for power switching mainly, is used for opening, closing direct current output; Resistance, diode, triode is had in current detecting and control unit; perform in order to current sampling, switch; electric current in switch element is detected, sampled; and react on switch element; reduce the saturation conduction degree of switch element, the power device in protection switch unit, and provide certain buffer time for overload protecting circuit; guarantee that, before overload protecting circuit action, switch element is not damaged.Utilize the electric current in current detecting and control unit sense switch unit; the maximum current of the current detecting utilizing inductance, diode and triode to form and control unit restriction output loop; equipment is protected, improves the short-circuit protection performance of photovoltaic charge controller.
In an embodiment, direct current component uses storage battery; Inductance and afterflow unit are made up of diode D1, inductance L 1, electrochemical capacitor C1; Current detecting and control unit are made up of resistance R1, R3, R5, R6, diode D2, triode Q2; Overload current signal sampling filtered electrical routing resistance R4, diode C3 are formed; Switch element is made up of switching tube Q1.
Physical circuit connects as shown in Figure 2, the anode DC+ of DC power supply connects tap one end of inductance L 1 and diode D1 negative pole, inductance L 1 other end connects electrochemical capacitor C1 positive pole, and tap one end is DC output end OUT+, diode D1 positive pole one end connects with electrochemical capacitor C1 negative pole and tap one end is DC output end OUT-, between diode D1 positive pole and electrochemical capacitor C1 negative pole, tap connecting valve pipe Q1 drains, the phase of switching tube Q1 extremely on be connected to resistance R1 one end, and tap one end connects diode D2 positive pole, the resistance R1 other end is provided with control signal test point, switching tube Q1 source electrode is provided with current sampling resistor R3, the R3 other end connects the negative terminal DC-of DC power supply and ground connection, two tap lines are provided with at resistance R3 and switching tube Q1 source electrode, first tap line is connected to resistance R4 one end, the resistance R4 other end connects electric capacity C3 one end and tap is current detection signal point, electric capacity C3 other end connecting triode Q2 emitter ground connection, second tap line contact resistance R5 one end, resistance R5 other end connecting triode Q2 base stage, diode D2 negative pole connecting triode Q2 collector electrode tap one end contact resistance R6, the resistance R6 other end is power detection signal point, by this circuit restriction output loop maximum current, improve the protective value of photovoltaic charge controller.
Direct current to be input in the inductance and afterflow element circuit, switching tube Q1, the current detecting be made up of resistance R1, R3, R5, R6, diode D2, triode Q2 and control unit circuit that are made up of diode D1, inductance L 1, electrochemical capacitor C1 and the overload current signal be made up of resistance R4, electric capacity C3 sampling filter circuit by DC+, DC-and to go by storage battery.
During work, export the load current of DC loop, by current sampling resistor R3, produce certain voltage U i, Ui=I*R, Ui during normal work is much smaller than the Ube of triode Q2, and Ube is generally about 0.7V.When output has short circuit; the electric current flow through on resistance R3 sharply increases; Ui is then made to increase fast, as Ui>Ube, triode Q2 conducting; the voltage drop of triode Q2 collector electrode is to about 0 volt; now diode D2 conducting, and the grid voltage of switching tube Q1 is pulled down to close to 0V, switching tube Q1 power releases saturation conduction; make loop current be limited in I=Ube/ (R3), thus protect switching tube Q1.
In inductance and afterflow element circuit when short circuit phenomenon occurs, the electric current of controlling load circuit increases fast, for the conducting of triode Q2, defencive function gains time, make before triode Q2 action, switching tube Q1 is not burned, because the electric current on inductance can not specially become, induced voltage equation on inductance is: UL=L (di/dt), during switching tube Q1 conducting generation output short-circuit, loop current should be (Uin-UL)/R3, by separating the differential equation, electric current in very short time when short circuit increases according to indicial response, inductance is larger, it is slower that electric current increases, utilize the ability of controlling electric current of inductance L 1, for triode Q2, switching tube Q1 protection act has won the time, reliable and stable.
The present invention is mainly used in small photovoltaic power generation system, and out-put supply is direct current, and load is also all the equipment of direct current electricity consumption.
Claims (3)
1. an output short-circuit protection circuit of low-power photovoltaic controller, it is characterized in that the anode DC+ of DC power supply connects tap one end of inductance L 1 and diode D1 negative pole, inductance L 1 other end connects electrochemical capacitor C1 positive pole, and tap one end is DC output end OUT+, diode D1 positive pole one end connects with electrochemical capacitor C1 negative pole one end and tap one end is DC output end OUT-, between diode D1 positive pole and electrochemical capacitor C1 negative pole, tap connecting valve pipe Q1 drains, the grid of switching tube Q1 is connected to resistance R1 one end, and tap one end connects diode D2 positive pole, the resistance R1 other end is provided with control signal test point, switching tube Q1 source electrode is provided with current sampling resistor R3, the current sampling resistor R3 other end connects the negative terminal DC-of DC power supply and ground connection, two tap lines are provided with at resistance R3 and switching tube Q1 source electrode, first tap line is connected to resistance R4 one end, the resistance R4 other end connects electric capacity C3 one end and tap is current detection signal point, electric capacity C3 other end connecting triode Q2 emitter ground connection, second tap line contact resistance R5 one end, resistance R5 other end connecting triode Q2 base stage, diode D2 negative pole connecting triode Q2 collector electrode tap one end contact resistance R6, the resistance R6 other end is power detection signal point, described switching tube Q1 is N channel enhancement metal-oxide-semiconductor, described triode Q2 is NPN type triode.
2. an output short-circuit protection circuit of low-power photovoltaic controller method, it is characterized in that the method is, direct-flow input end is storage battery, by DC+, DC-direct current is input to the inductance and afterflow element circuit that are made up of diode D1, inductance L 1, electrochemical capacitor C1; The current detecting of switching tube Q1, resistance R1, R3, R5, R6, diode D2, triode Q2 composition and control unit; Resistance R4, electric capacity C3 go in overload current signal sampling filter circuit,
During work, export the load current of DC loop, by the current sampling resistor of resistance R3, create voltage, Ui=IR, make Ui when normally working much smaller than the Ube of triode Q2, Ube is 0.7V, when output has short circuit, the electric current flow through on resistance R3 sharply increases, Ui is then made to increase fast, as Ui>Ube, triode Q2 conducting, then the voltage drop of triode Q2 collector electrode is to 0 volt, now diode D2 conducting, and the grid voltage of switching tube Q1 is pulled down to close to 0V, switching tube Q1 power releases saturation conduction, loop current is made to be limited in I=Ube/R3, thus protect Q1.
3. a kind of output short-circuit protection circuit of low-power photovoltaic controller method as claimed in claim 2, it is characterized in that the method for inductance and afterflow element circuit is for occurring when short circuit phenomenon, the electric current of controlling load circuit increases fast, for the conducting of triode Q2, defencive function gains time, make before triode Q2 action, switching tube Q1 is not burned, because the electric current on inductance can not specially become, induced voltage equation on inductance is: UL=L (di/dt), when switching tube Q1 conducting, when there is output short-circuit, loop current should be (Uin-UL)/R3, by separating the differential equation, electric current in very short time when short circuit increases according to indicial response, inductance is larger, it is slower that electric current increases, because the ability of controlling electric current of inductance L 1, for triode Q2, switching tube Q1 protection act has won the time, make protection reliable and stable.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210239642.8A CN102751969B (en) | 2012-07-11 | 2012-07-11 | Output short-circuit protection circuit and method of low-power photovoltaic controller |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210239642.8A CN102751969B (en) | 2012-07-11 | 2012-07-11 | Output short-circuit protection circuit and method of low-power photovoltaic controller |
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| CN102751969A CN102751969A (en) | 2012-10-24 |
| CN102751969B true CN102751969B (en) | 2015-01-21 |
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| CN110611292B (en) * | 2019-10-26 | 2024-03-12 | 广州睿圣电子科技有限公司 | PFC circuit and protection circuit thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2396572Y (en) * | 1999-09-24 | 2000-09-13 | 王汝赳 | Glow ion nitriding furnace pulse power |
| CN201563058U (en) * | 2009-11-24 | 2010-08-25 | 山东中烟工业公司青州卷烟厂 | Direct-current voltage-stabilizing supply unit |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06311739A (en) * | 1993-04-19 | 1994-11-04 | Fujitsu Ltd | Input overcurrent suppression circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2396572Y (en) * | 1999-09-24 | 2000-09-13 | 王汝赳 | Glow ion nitriding furnace pulse power |
| CN201563058U (en) * | 2009-11-24 | 2010-08-25 | 山东中烟工业公司青州卷烟厂 | Direct-current voltage-stabilizing supply unit |
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Effective date of registration: 20210819 Address after: 200000 room 3272, building 4, No. 495, Yuejin South Road, Xinhai Town, Chongming District, Shanghai (Guangming rice industry economic Park) Patentee after: Shanghai Lejia Technology Co.,Ltd. Address before: 201203 room 221A, building 1, No. 88 Darwin Road, Zhangjiang High Tech Park, Pudong New Area, Shanghai Patentee before: SHANGHAI XIANJIA NEW ENERGY TECHNOLOGY Co.,Ltd. |
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Address after: Room 307, Building 10A, Zilang Science and Technology City, No. 60 Chongzhou Avenue, Development Zone, Nantong City, Jiangsu Province, 226010 Patentee after: Nantong Le Chuangxin Energy Co.,Ltd. Country or region after: China Address before: 200000 room 3272, building 4, No. 495, Yuejin South Road, Xinhai Town, Chongming District, Shanghai (Guangming rice industry economic Park) Patentee before: Shanghai Lejia Technology Co.,Ltd. Country or region before: China |