CN204595054U - A kind of leak current detector for photovoltaic inverter - Google Patents
A kind of leak current detector for photovoltaic inverter Download PDFInfo
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- CN204595054U CN204595054U CN201520193688.XU CN201520193688U CN204595054U CN 204595054 U CN204595054 U CN 204595054U CN 201520193688 U CN201520193688 U CN 201520193688U CN 204595054 U CN204595054 U CN 204595054U
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Abstract
The utility model discloses a kind of leak current detector for photovoltaic inverter.Pick-up unit comprises leakage current sampling module and micro controller module.Leakage current sampling module comprises magnet ring, oscillatory circuit, self-checking circuit, filtering link etc., the sampling of primary responsibility leakage current and the interference of filtering oscillation frequency; The STM32F030F4 that microcontroller is little primarily of volume, price is low, multiple functional and periphery pin circuitry composition thereof, microcontroller is responsible for control, the correction of leakage current test, and carries out message exchange with the master controller of outside.The orders such as whole testing process is shaken hands according to powering on, self-inspection, cycle detection, abnormal alarm are carried out.This leak current detection device structure is simple, easily realizes, can realize the correction of scale-up factor, enable the inverter being applicable to different capabilities with a leak current detection device, and the unitized production for inverter leakage current pick-up unit provides convenient.
Description
Technical field
The utility model relates to power technique fields, particularly a kind of leak current detector for photovoltaic inverter.
Background technology
Not containing the non-isolated inverter of transformer (high frequency, low frequency), because it has obvious advantage on efficiency, volume, weight, cost, receive the attention of domestic and international scientific research people and pursue.But due to without transformer device structure, photovoltaic system and electrical network have had direct electrical connection, easily cause the significantly increase of leakage current and common mode current, cause serious potential safety hazard, therefore must introduce leakage current test.
Technical specifications specifies, when leakage current mean value is 30mA, 60mA, 100mA, the trip time of regulation is respectively 0.3s, 0.15s and 0.04s.Leak current detection device is in the market all the leakage current test for single product device, and each leak current detection device can only be applicable to a certain single paragraph type, is unfavorable for the unitized production of inverter.And unified modulesization can use problem to solve various capacity specifications inverter, this patent is improved on the leak current detection device of routine, increases zero offset capability.For the inverter of different size, pick-up unit can carry out adjustment and correct, and realizes unitized production.
Utility model content
Fundamental purpose of the present utility model is, for above-mentioned deficiency of the prior art, photovoltaic inverter leakage current is provided to detect dress, the stability of leakage current test can be improved, and realize the unitized production being applicable to the leak current detection device of different capabilities inverter, there is very high cost performance, be very suitable for extensively promoting and using.
A kind of leak current detector for photovoltaic inverter, comprise leakage current sample circuit and microcontroller composition, leakage current sample circuit comprises magnet ring, oscillatory circuit, filtering circuit and self-checking circuit, and leakage current sample circuit is responsible for the sampling of leakage current and filtering noise information and oscillation frequency interference; Microcontroller to the correction of the sampled value of leakage current sample circuit, and carries out signal transmission with external piloting control device;
Oscillatory circuit is connected with magnet ring, vibration environment is provided to magnet ring, magnet ring is also connected with filtering circuit, the leakage current that magnet ring detects circuit after filtering, filtering interference signals, and then pass to microcontroller carry out ADC (Analog-to-Digital Converter, analog to digital converter) sampling; Self-checking circuit is connected with magnet ring with microcontroller, and the self-test signal by microcontroller controls to trigger, and the work of self-checking circuit can make magnet ring induce the current value of a quota, and circuit feeds back to microcontroller more after filtering;
Described magnet ring is operated in oscillatory regime, for detecting the leakage current in photovoltaic DC-to-AC converter;
Described oscillatory circuit makes magnet ring starting of oscillation, avoids magnet ring nonoscillatory and enters state of saturation, thus loses the measuring ability to photovoltaic inverter leakage current;
Described filtering circuit is used for the current increment that filtering oscillatory circuit causes, and guarantees the accurate and stable of sampling;
Described self-checking circuit, under the control of microcontroller triggers, can make magnet ring induce the electric current of a 50mA, then feed back to microcontroller, judge whether pick-up unit can normally work thus.
Further, described microcontroller adopts the STM32F030F4 having 20 pins, and this model microcontroller is small, low price, multiple functional, has promotional value.
Compared to prior art, it is simple that the utility model has structure, and the advantage easily realized, has coefficient correction function simultaneously, can according to different working environments, and resize ratio coefficient, meets the different needs.
Accompanying drawing explanation
Fig. 1 is the block diagram of the utility model inverter leakage current pick-up unit.
Fig. 2 is the hardware circuit block scheme of the utility model inverter leakage current pick-up unit.
Fig. 3 is that the one of the microcontroller of the utility model inverter leakage current pick-up unit controls example flow chart.
Fig. 4 is the experiment block scheme of the utility model inverter leakage current pick-up unit.
Embodiment
Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail, but enforcement of the present utility model and protection are not limited thereto, and do not describe part in detail especially if having below, is all that those skilled in the art can refer to existing techniques in realizing.
Fig. 1 is the block diagram of inverter leakage current pick-up unit in the utility model embodiment.
With reference to shown in Fig. 1, a kind of leak current detector for photovoltaic inverter, comprises sample circuit and microcontroller.
Further, described inverter leakage current pick-up unit, sample circuit is responsible for the collection of leakage current, filtering noise information and oscillation frequency interference.
Described inverter leakage current pick-up unit, microcontroller is responsible for control and the correction of whole leak current detection device.
Further, described inverter leakage current pick-up unit, microcontroller is responsible for carrying out signal transmission with peripheral control unit.Described microcontroller adopts the STM32F030F4 having 20 pins.
Fig. 2 is the utility model inverter leakage current pick-up unit hardware circuit block scheme.
With reference to shown in Fig. 2, described hardware circuit comprises oscillatory circuit, self-checking circuit, filtering circuit.
Further, described oscillatory circuit is by the connection of signal at comparer 1 and comparer 2 in-phase end and end of oppisite phase, two comparers are made to be in different conditions all the time, different conditions the is corresponding again different working modes of comparer 3, finally form a degenerative working method, make circuit can keep the oscillatory work continued.Oscillatory circuit makes magnet ring be in oscillatory regime, makes it keep unsaturated state, ensures that it can normally to leakage current test.
Further, described self-checking circuit is by microprocessor controls, and mainly utilize the 2.5V accurate reference pin of stabilivolt as control signal in process of self-test, self-inspection can normally work in order to ensure hardware circuit.
Further, described wave filter adopts the voltage controlled voltage source type low-pass filter circuit design of two rank, this filtering circuit cutoff frequency f
c=1.2kHz, and collection signal is 50Hz, can guarantee normal sample.
Below only a kind of application example of the present utility model (program part is that those skilled in the art can realize according to actual conditions) Fig. 3 is the microprocessor controls method block scheme of the utility model inverter leakage current pick-up unit.
Main MCU (Micro Control Unit in figure, microcontroller) represent external piloting control device, GFCI (Ground Fault Circuit, leakage current test), GFCI_MCU (Ground Fault CircuitInterrupter Micro Control Unit, leak current detection device microcontroller) represents the microcontroller that leak current detection device comprises.
With reference to shown in Fig. 3, microcontroller is responsible for control and the correction of whole leak current detection device.
The first step, after device powers on, first carries out initialization, reads correction coefficient, and correction coefficient stores in the microcontroller, and correction coefficient adjusts because of the difference of inverter capacity, guarantees that current sensing means can be applicable to the inverter of different capabilities;
Second step, set up handshake between microcontroller and external piloting control device, this dohandshake action is always carried out with certain frequency f, shakes hands unsuccessful, restarts leak current detection device, return the first step, external piloting control device does not receive handshake continuous 5 times, then report an error, and leak current detection device damages, if shake hands successfully, then enter the 3rd step, if there is no self-test signal, then enter the 4th step;
3rd step, device is after initialization powers on and realizes normal handshake communication, and microcontroller provides a trigger pip to self-checking circuit, and whether testing fixture is normal, self-test signal only initialization power on Shi Caihui trigger, device can not trigger self-test signal when normal work, if continuous 5 fail self-tests, microcontroller externally master controller reports an error, leak current detection device damages, if self-inspection success, then carry out next step, carry out normal leakage current test;
4th step; leakage current sample circuit starts the leakage current detecting photovoltaic DC-to-AC converter normally; the electric current that leakage current sample circuit detects passes to microcontroller; carry out correcting and judging; once occur that leakage current exceeds standard; microcontroller then externally master controller send warning information, trigger protection action.
Fig. 4 is the simulated experiment block scheme of the utility model inverter leakage current pick-up unit.
With reference to shown in Fig. 4, application platform is hooked rifle (401,402), photovoltaic DC-to-AC converter 403, inverter leakage current pick-up unit, electrical network and monitoring software formed by direct supply 401, isolating switch (S1, S2), electric current.Close circuit breaker 1 (S1) can record positive pole leakage current over the ground, and close circuit breaker 2 (S2) can record negative pole leakage current over the ground.
Further, the working condition of system during test leakage current gradual change, test result is as shown in table 1.
Table 1 leakage current gradual change experimental data
Further, the working condition of system during the sudden change of test leakage current, test result is as shown in table 2.
Table 2 leakage current mutating experiment data
In sum, no matter be the leakage current of gradual change or the leakage current of sudden change, this inverter leakage current pick-up unit can be accomplished to sample accurately and make protection act accurately simultaneously, complex technique requirement actuation time.
The foregoing is only preferred embodiment of the present utility model; not thereby its scope of the claims is limited; every equivalent structure transformation utilizing the utility model instructions and accompanying drawing content to do; directly or indirectly be used in the technical field that other are relevant, be all in like manner included in scope of patent protection of the present utility model.
Claims (2)
1. a leak current detector for photovoltaic inverter, it is characterized in that comprising leakage current sample circuit and microcontroller composition, leakage current sample circuit comprises magnet ring, oscillatory circuit, filtering circuit and self-checking circuit, and leakage current sample circuit is responsible for the sampling of leakage current and filtering noise information and oscillation frequency interference;
Oscillatory circuit is connected with magnet ring, and provide vibration environment to magnet ring, magnet ring is also connected with filtering circuit, the leakage current that magnet ring detects circuit after filtering, filtering interference signals, and then passes to microcontroller and carry out analog to digital conversion sampling; Self-checking circuit is connected with magnet ring with microcontroller, and the self-test signal by microcontroller controls to trigger, and the work of self-checking circuit can make magnet ring induce the current value of a quota, and circuit feeds back to microcontroller more after filtering;
Described magnet ring is operated in oscillatory regime, for detecting the leakage current in photovoltaic DC-to-AC converter;
Described oscillatory circuit makes magnet ring starting of oscillation, avoids magnet ring nonoscillatory and enters state of saturation, thus loses the measuring ability to photovoltaic inverter leakage current.
2. a kind of leak current detector for photovoltaic inverter according to claim 1, is characterized in that described microcontroller adopts the STM32F030F4 having 20 pins.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201520193688.XU CN204595054U (en) | 2015-04-01 | 2015-04-01 | A kind of leak current detector for photovoltaic inverter |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201520193688.XU CN204595054U (en) | 2015-04-01 | 2015-04-01 | A kind of leak current detector for photovoltaic inverter |
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| CN204595054U true CN204595054U (en) | 2015-08-26 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106019194A (en) * | 2016-06-29 | 2016-10-12 | 张家港友诚科技机电有限公司 | Test method for electric leakage detection circuit |
| WO2018165970A1 (en) * | 2017-03-17 | 2018-09-20 | 浙江巨磁智能技术有限公司 | Leakage current sensor, and apparatus for monitoring leakage current |
| CN105608413B (en) * | 2014-11-14 | 2020-04-28 | 深圳市汇顶科技股份有限公司 | Fingerprint sensor latch recovery mechanism based on status monitoring and handshaking |
-
2015
- 2015-04-01 CN CN201520193688.XU patent/CN204595054U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105608413B (en) * | 2014-11-14 | 2020-04-28 | 深圳市汇顶科技股份有限公司 | Fingerprint sensor latch recovery mechanism based on status monitoring and handshaking |
| CN106019194A (en) * | 2016-06-29 | 2016-10-12 | 张家港友诚科技机电有限公司 | Test method for electric leakage detection circuit |
| WO2018165970A1 (en) * | 2017-03-17 | 2018-09-20 | 浙江巨磁智能技术有限公司 | Leakage current sensor, and apparatus for monitoring leakage current |
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