CN202486217U - Ground-insulated resistance test system of double-branch input photovoltaic grid-connected inverter - Google Patents
Ground-insulated resistance test system of double-branch input photovoltaic grid-connected inverter Download PDFInfo
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- CN202486217U CN202486217U CN2012201285014U CN201220128501U CN202486217U CN 202486217 U CN202486217 U CN 202486217U CN 2012201285014 U CN2012201285014 U CN 2012201285014U CN 201220128501 U CN201220128501 U CN 201220128501U CN 202486217 U CN202486217 U CN 202486217U
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Abstract
The utility model relates to the technology of a photovoltaic grid-connected inverter, and particularly relates to a ground-insulated resistance test system of a double-branch input photovoltaic grid-connected inverter. The ground-insulated resistance test system comprises a boost circuit 1 capable of boosting a photovoltaic cell of a first path, a boost circuit 2 capable of boosting a photovoltaic cell of a second path, and a PV1 voltage sampling circuit capable of sampling the voltage of the photovoltaic cell of the first path, and a PV2 voltage sampling circuit capable of sampling the voltage of the photovoltaic cell of the second path, a lower bridge arm voltage sampling circuit, a resistance switching circuit and a microprocessor. The ground-insulated resistance test system provided by the utility model realizes the on-line real-time testing of the ground-insulated resistance of input photovoltaic cells of two branches, so that the round-insulated resistance test system can judge whether the ground-insulated resistance of the photovoltaic grid-connected inverter meets the safety requirements on line or not, and further, the round-insulated resistance test system permits or forbids the starting operation of the photovoltaic grid-connected inverter so as to ensure the safe and reliable operation of the photovoltaic grid-connected inverter.
Description
Technical field
The utility model relates to the photovoltaic combining inverter technology, is specifically related to a kind of pair of branch road input photovoltaic combining inverter insulation against ground resistance detection system.
Background technology
In the parallel network power generation technology; The output voltage of photovoltaic cell is than higher; For example: the photovoltaic cell output voltage of powerful photovoltaic combining inverter is up to more than the 600V because the photovoltaic battery panel of photovoltaic cell be open-air placement, the positive pole, negative pole that weather conditions such as dust, sleet, dense fog all can influence photovoltaic cell over the ground (below alleged " over the ground "; All be meant " for the earth ", i.e. Earth) insulation variation.As a kind of high-pressure system, a quality that key index is exactly the insulation degree of photovoltaic combining inverter safety, whether the state of insulation that the insulation measurement technology can be judged current system is good, and the situation of change of state of insulation.Photovoltaic combining inverter need carry out the detection of the insulation against ground resistance of photovoltaic cell every day before the start, require the insulation against ground resistance of combining inverter to be not less than 1K Ω/V in the TUV authentication.
Two branch road input photovoltaic combining inverters are a kind of combining inverters that adopt two branch road photovoltaic cell inputs; Because the insulation resistance between two branch road photovoltaic cell inputs over the ground intercouples; Less to the detection technique research of the insulation resistance between two branch road photovoltaic cell inputs over the ground at present; Short of reliable testing circuit and detection method are to such an extent as to exist potential safety hazard in the course of work of two branch road photovoltaic combining inverters.
The utility model content
In order to address the above problem, the utility model provides a kind of pair of branch road input photovoltaic combining inverter insulation against ground resistance detection system, has realized that the online in real time of the anodal insulation against ground resistance of two branch road photovoltaic cells, negative pole insulation against ground resistance is measured.
Two branch roads input photovoltaic combining inverter insulation against ground resistance detection system, the BOOST circuit two that comprises BOOST circuit one that first via photovoltaic cell is boosted, the second road photovoltaic cell is boosted, the PV1 voltage sampling circuit that first via photovoltaic cell voltage is sampled, the PV2 voltage sampling circuit that the second road photovoltaic cell voltage is sampled, bridge arm voltage sample circuit, resistance switch circuit and microprocessor down;
First end of said BOOST circuit one is connected with the positive pole of first via photovoltaic cell, and second end of said BOOST circuit one is connected with the positive pole of dc bus, and the control end of said BOOST circuit one is connected with a PWM port of said microprocessor;
First end of said BOOST circuit two is connected with the positive pole of the second road photovoltaic cell, and second end of said BOOST circuit two is connected with the positive pole of dc bus, and the control end of said BOOST circuit two is connected with the 2nd PWM port of said microprocessor;
The public negative pole of the first via photovoltaic cell and the second road photovoltaic cell is connected with first end of said resistance switch circuit, the second termination the earth of said resistance switch circuit, and said resistance switch circuit control end is connected with an I/O port of said microprocessor;
The output terminal of said PV1 voltage sampling circuit is connected with an A/D port of said microprocessor; The output terminal of said PV2 voltage sampling circuit is connected with the 2nd A/D port of said microprocessor;
The public negative pole of the first via photovoltaic cell and the second road photovoltaic cell is connected with said first end of bridge arm voltage sample circuit down; The said second termination the earth of bridge arm voltage sample circuit down, the said output terminal of bridge arm voltage sample circuit down is connected with the 3rd A/D port of said microprocessor.
The public negative pole of the first via photovoltaic cell and the second road photovoltaic cell is connected with the negative pole of dc bus.
Wherein, said microprocessor comprises the 3rd PWM port set, and said the 3rd PWM port set is connected with the inverter circuit of photovoltaic combining inverter.
Wherein, said microprocessor also comprises the 2nd I/O port, and said the 2nd I/O port is connected with warning circuit.
Wherein, said resistance switch circuit comprises the subsidiary resistance R
0With switch S 1, said switch S 1 is switching tube, relay or optocoupler.
Wherein, said PV1 voltage sampling circuit adopts differential amplifier circuit, linear isolating amplifier circuit or voltage sensor sample circuit; Said PV2 voltage sampling circuit adopts differential amplifier circuit, linear isolating amplifier circuit or voltage sensor sample circuit.
Wherein, said microprocessor adopts the FIR digital filtering algorithm that the A/D sampled signal is carried out digital filtering and handles, and this microprocessor is the DSP microprocessor.
The beneficial effect of the utility model is: two branch roads of the utility model are imported photovoltaic combining inverter insulation against ground resistance detection system; Circuit is realized simple; Measuring accuracy is high; The anodal insulation against ground resistance of photovoltaic cell of two branch road inputs, the online in real time measurement of photovoltaic cell negative pole insulation against ground resistance have been realized; Whether anodal insulation against ground resistance of inline diagnosis photovoltaic cell and photovoltaic cell negative pole insulation against ground resistance satisfy the safety requirement, and then take corresponding measure, have guaranteed that photovoltaic combining inverter works safely and reliably.
Description of drawings
Fig. 1 is the equivalent-circuit model figure that two branch roads are imported photovoltaic combining inverter insulation against ground resistance detection system.
Fig. 2 is the circuit realization theory diagram that two branch roads of the utility model are imported photovoltaic combining inverter insulation against ground resistance detection system.
Description of reference numerals is following:
10-microprocessor, 11-PV1 voltage sampling circuit,
12-PV2 voltage sampling circuit,
13-BOOST circuit, one, 14-BOOST circuit two,
15-resistance switch circuit, 16-following bridge arm voltage sample circuit,
17-inverter circuit, 18-warning circuit.
Embodiment
For the purpose, technical scheme and the advantage that make utility model is clearer,, the utility model is further elaborated below in conjunction with accompanying drawing and embodiment.
Referring to Fig. 1 and Fig. 2; Two branch roads input photovoltaic combining inverter insulation against ground resistance detection system, the BOOST circuit 2 14 that comprises BOOST circuit 1 that first via photovoltaic cell is boosted, the second road photovoltaic cell is boosted, the PV1 voltage sampling circuit 11 that first via photovoltaic cell voltage is sampled, the PV2 voltage sampling circuit 12 that the second road photovoltaic cell voltage is sampled, bridge arm voltage sample circuit 16, resistance switch circuit 15 and microprocessor 10 down;
The BOOST circuit is a kind of booster circuit; The effect of BOOST circuit one and BOOST circuit two is to boost to needed DC bus-bar voltage to the input voltage of two-way photovoltaic cell respectively; Guarantee the inverter circuit operate as normal, carry out the function of maximal power tracing (MPPT) simultaneously photovoltaic cell.
First end of said BOOST circuit 1 is connected with the positive pole of first via photovoltaic cell, and second end of said BOOST circuit 1 is connected with the positive pole of dc bus, and the control end of said BOOST circuit 1 is connected with a PWM port of said microprocessor 10;
First end of said BOOST circuit 2 14 is connected with the positive pole of the second road photovoltaic cell; Second end of said BOOST circuit 2 14 is connected with the positive pole of dc bus; Be to be connected with dc bus after first via photovoltaic cell boosts through BOOST circuit 1, the second road photovoltaic cell is connected with dc bus after boosting through BOOST circuit 2 14; The control end of said BOOST circuit 2 14 is connected with the 2nd PWM port of said microprocessor 10;
The public negative pole PV-of the first via photovoltaic cell and the second road photovoltaic cell is connected with first end of said resistance switch circuit 15; The second termination the earth of said resistance switch circuit 15, the control end of said resistance switch circuit 15 is connected with an I/O port of said microprocessor 10;
The public negative pole PV-of the first via photovoltaic cell and the second road photovoltaic cell is connected with the negative pole of dc bus;
Be provided with PV1 voltage sampling circuit 11 between the anodal and public negative pole PV-of first via photovoltaic cell, the output terminal of said PV1 voltage sampling circuit 11 is connected with an A/D port of said microprocessor 10; Be provided with PV2 voltage sampling circuit 12 between the anodal and public negative pole PV-of second road photovoltaic cell, the output terminal of said PV2 voltage sampling circuit 12 is connected with the 2nd A/D port of said microprocessor 10;
The public negative pole PV-of the first via photovoltaic cell and the second road photovoltaic cell is connected with said first end of bridge arm voltage sample circuit 16 down; The said second termination the earth of bridge arm voltage sample circuit 16 down, the said output terminal of bridge arm voltage sample circuit 16 down is connected with the 3rd A/D port of said microprocessor 10.
The photovoltaic cell string that the first via photovoltaic cell and the second road photovoltaic cell are made up of some photovoltaic cell plate serioparallels.
Wherein, said microprocessor 10 comprises the 2nd I/O port, and said the 2nd I/O port is connected with warning circuit 18.
Wherein, said microprocessor 10 also comprises the 3rd PWM port set, and said the 3rd PWM port set is connected with the inverter circuit 17 of photovoltaic combining inverter.The 3rd PWM port set is one group of PWM mouth.
Wherein, said resistance switch circuit 15 comprises the subsidiary resistance R by exterior arrangement
0With switch S 1, the subsidiary resistance R
0An end be connected the subsidiary resistance R with an end of switch S 1
0Another termination the earth, the other end of switch S 1 connects public negative pole PV-, said switch S 1 is switching tube, relay or optocoupler.
Wherein, said PV1 voltage sampling circuit 11 adopts differential amplifier circuit or voltage sensor to isolate sample circuit; Said PV2 voltage sampling circuit 12 adopts differential amplifier circuit or voltage sensor to isolate sample circuit.
Wherein, said microprocessor 10 adopts the FIR digital filtering algorithm that the A/D sampled signal is carried out digital filtering and handles, and this microprocessor 10 is the DSP microprocessor.
The detection method of a kind of pair of branch road input photovoltaic combining inverter insulation against ground resistance detection system may further comprise the steps:
A, microprocessor 10 are closed inverter circuit 17, BOOST circuit 1 and BOOST circuit 2 14; Input voltage signal V through PV1 voltage sampling circuit 11 sampling first via photovoltaic cells
PV1Input voltage signal V through PV2 voltage sampling circuit 12 samplings the second road photovoltaic cell
PV2
Switch S 1 closure of B, microprocessor 10 controlling resistance on-off circuits 15 makes the subsidiary resistance R
0With following brachium pontis parallel connection, through brachium pontis output voltage signal u1 under bridge arm voltage sample circuit 16 is sampled down;
The switch S 1 of C, microprocessor 10 controlling resistance on-off circuits 15 is broken off, and makes the subsidiary resistance R
0With following brachium pontis disengaging, microprocessor 10 cuts out BOOST circuit 2 14, and control BOOST circuit 1 makes the positive pole and the negative pole input short circuit of first via photovoltaic cell, through brachium pontis output voltage signal u2 under bridge arm voltage sample circuit 16 is sampled down; Photovoltaic cell itself is to allow short circuit;
D, microprocessor 10 are closed BOOST circuit 1, and control BOOST circuit 2 14 makes the positive pole of the second road photovoltaic cell and negative pole import short circuit, through brachium pontis output voltage signal u3 under bridge arm voltage sample circuit 16 is sampled down;
E, microprocessor 10 calculate the insulation resistance R of the positive pole of first via photovoltaic cell to the earth respectively according to the voltage signal u1, u2 and the u3 that obtain
1+, the positive pole of the second road photovoltaic cell is to the insulation resistance R of the earth
2+, and the public negative pole PV-of the first via photovoltaic cell and the second road photovoltaic cell is to the equivalent parallel insulation resistance R-of the earth;
The public negative pole PV-of the first via photovoltaic cell and the second road photovoltaic cell and the circuit between the earth constitute described brachium pontis down.
Wherein, the calculating of said step e is specially:
E1, according to voltage signal u1, set up first relation equation e1 by Kirchhoff's laws of electric circuit:
E2, according to voltage signal u2, set up second relation equation e2 by Kirchhoff's laws of electric circuit:
E3, according to power supply signal u3, set up the 3rd relation equation e3 by Kirchhoff's laws of electric circuit:
;
Find the solution the ternary linear function group of forming by e1, e2, e3, draw R
1+, R
2+, R-resistance value.
Ternary linear function group is:
Make
, the group of solving an equation e4 can get:
That is:
Calculate R respectively according to above-mentioned expression formula
1+, R
2+, R-resistance value.
Further, after step e, also comprise step F: judge R
1+, R
2+, R-resistance value whether satisfy the safety requirement.The concrete numerical value that safety requires is kept in the microprocessor in advance.
Further, after step F, also comprise step G: if R
1+, R
2+, R-resistance value satisfy the safety requirement, then allow photovoltaic combining inverter startup work; Otherwise, forbid photovoltaic combining inverter startup work, and control warning circuit 18 sends alerting signal.
Forbid that the BOOST circuit working is exactly that the switching tube of controlling the BOOST circuit is in off-state always.
Forbid that equally inverter circuit work is exactly that the switching tube of controlling inverter circuit is in off-state always.
Two branch roads of the utility model are imported photovoltaic combining inverter insulation against ground resistance detection system; Circuit is realized simple; Measuring accuracy is higher, has realized the anodal insulation against ground resistance of photovoltaic cell of two branch road inputs, the online in real time measurement of photovoltaic cell negative pole insulation against ground resistance, judges whether anodal insulation against ground resistance of photovoltaic cell and photovoltaic cell negative pole insulation against ground resistance satisfy the safety requirement; And then take corresponding measure, guaranteed that photovoltaic combining inverter works safely and reliably.
Above content is merely the preferred embodiment of the utility model; For those of ordinary skill in the art; According to the thought of the utility model, the part that on embodiment and range of application, all can change, this description should not be construed as the restriction to the utility model.
Claims (6)
1. two branch roads input photovoltaic combining inverter insulation against ground resistance detection system is characterized in that: the BOOST circuit two that comprises BOOST circuit one that first via photovoltaic cell is boosted, the second road photovoltaic cell is boosted, the PV1 voltage sampling circuit that first via photovoltaic cell voltage is sampled, the PV2 voltage sampling circuit that the second road photovoltaic cell voltage is sampled, bridge arm voltage sample circuit, resistance switch circuit and microprocessor down;
First end of said BOOST circuit one is connected with the positive pole of first via photovoltaic cell, and second end of said BOOST circuit one is connected with the positive pole of dc bus, and the control end of said BOOST circuit one is connected with a PWM port of said microprocessor;
First end of said BOOST circuit two is connected with the positive pole of the second road photovoltaic cell, and second end of said BOOST circuit two is connected with the positive pole of dc bus, and the control end of said BOOST circuit two is connected with the 2nd PWM port of said microprocessor;
The public negative pole of the first via photovoltaic cell and the second road photovoltaic cell is connected with first end of said resistance switch circuit, the second termination the earth of said resistance switch circuit, and said resistance switch circuit control end is connected with an I/O port of said microprocessor;
The output terminal of said PV1 voltage sampling circuit is connected with an A/D port of said microprocessor; The output terminal of said PV2 voltage sampling circuit is connected with the 2nd A/D port of said microprocessor;
The public negative pole of the first via photovoltaic cell and the second road photovoltaic cell is connected with said first end of bridge arm voltage sample circuit down; The said second termination the earth of bridge arm voltage sample circuit down, the said output terminal of bridge arm voltage sample circuit down is connected with the 3rd A/D port of said microprocessor.
2. according to claim 1 pair of branch road input photovoltaic combining inverter insulation against ground resistance detection system, it is characterized in that: said microprocessor also comprises the 3rd PWM port set, said the 3rd PWM port set is connected with the inverter circuit of photovoltaic combining inverter.
3. according to claim 1 pair of branch road input photovoltaic combining inverter insulation against ground resistance detection system, it is characterized in that: said microprocessor comprises the 2nd I/O port, said the 2nd I/O port is connected with warning circuit.
4. according to claim 1 pair of branch road input photovoltaic combining inverter insulation against ground resistance detection system, it is characterized in that: said resistance switch circuit comprises the subsidiary resistance R
0With switch S 1, said switch S 1 is switching tube, relay or optocoupler.
5. according to claim 1 pair of branch road input photovoltaic combining inverter insulation against ground resistance detection system, it is characterized in that: said PV1 voltage sampling circuit adopts differential amplifier circuit, linear isolating amplifier circuit or voltage sensor sample circuit; Said PV2 voltage sampling circuit adopts differential amplifier circuit, linear isolating amplifier circuit or voltage sensor sample circuit.
6. according to claim 1 pair of branch road input photovoltaic combining inverter insulation against ground resistance detection system; It is characterized in that: said microprocessor adopts the FIR digital filtering algorithm that the A/D sampled signal is carried out digital filtering and handles, and this microprocessor is the DSP microprocessor.
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Cited By (7)
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CN102621394A (en) * | 2012-03-30 | 2012-08-01 | 广东易事特电源股份有限公司 | System and method for detecting insulation resistance to ground of dual-branch input photovoltaic grid-connected inverter |
CN104422825A (en) * | 2013-08-29 | 2015-03-18 | 浙江万向太阳能有限公司 | Method and method for detecting insulation resistance against ground of DC power supply |
CN105738706A (en) * | 2016-04-15 | 2016-07-06 | 易事特集团股份有限公司 | Method and apparatus for testing insulated grounding resistance of photovoltaic inverter |
CN106093590A (en) * | 2016-08-25 | 2016-11-09 | 安徽赛新电源科技有限公司 | Photovoltaic combining inverter multichannel input array impedance ground testing circuit and method |
CN109752665A (en) * | 2019-03-22 | 2019-05-14 | 上海度普新能源科技有限公司 | A kind of battery pack insulation detecting circuit and detection method |
CN110456154A (en) * | 2019-07-26 | 2019-11-15 | 华为技术有限公司 | Insulation resistance detection circuit and method |
CN115210585A (en) * | 2020-03-11 | 2022-10-18 | 弗罗纽斯国际有限公司 | Method for determining insulation resistance of photovoltaic system to ground and photovoltaic inverter |
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2012
- 2012-03-30 CN CN2012201285014U patent/CN202486217U/en not_active Expired - Fee Related
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
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CN102621394A (en) * | 2012-03-30 | 2012-08-01 | 广东易事特电源股份有限公司 | System and method for detecting insulation resistance to ground of dual-branch input photovoltaic grid-connected inverter |
CN104422825A (en) * | 2013-08-29 | 2015-03-18 | 浙江万向太阳能有限公司 | Method and method for detecting insulation resistance against ground of DC power supply |
CN104422825B (en) * | 2013-08-29 | 2017-10-27 | 浙江万向太阳能有限公司 | A kind of direct-current power ground insulation impedance detection apparatus and method |
CN105738706A (en) * | 2016-04-15 | 2016-07-06 | 易事特集团股份有限公司 | Method and apparatus for testing insulated grounding resistance of photovoltaic inverter |
CN106093590A (en) * | 2016-08-25 | 2016-11-09 | 安徽赛新电源科技有限公司 | Photovoltaic combining inverter multichannel input array impedance ground testing circuit and method |
CN109752665A (en) * | 2019-03-22 | 2019-05-14 | 上海度普新能源科技有限公司 | A kind of battery pack insulation detecting circuit and detection method |
CN110456154A (en) * | 2019-07-26 | 2019-11-15 | 华为技术有限公司 | Insulation resistance detection circuit and method |
US11500001B2 (en) | 2019-07-26 | 2022-11-15 | Huawei Digital Power Technologies Co., Ltd. | Insulation resistance detection circuit and method |
CN115210585A (en) * | 2020-03-11 | 2022-10-18 | 弗罗纽斯国际有限公司 | Method for determining insulation resistance of photovoltaic system to ground and photovoltaic inverter |
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