CN209267432U - A kind of LCL filtering gird-connected inverter protection circuit - Google Patents
A kind of LCL filtering gird-connected inverter protection circuit Download PDFInfo
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- CN209267432U CN209267432U CN201821534355.9U CN201821534355U CN209267432U CN 209267432 U CN209267432 U CN 209267432U CN 201821534355 U CN201821534355 U CN 201821534355U CN 209267432 U CN209267432 U CN 209267432U
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Abstract
The utility model provides a kind of LCL filtering gird-connected inverter protection circuit; this protection circuit uses the dual overvoltage protection strategy of electronic power switch and inverter entirety; the a set of ZnO varistor of each switch designs is protected; simultaneously; again using entire inverter as protected object, in inverter input/output terminal and filter capacitor end difference a set of ZnO varistor in parallel.When overvoltage is greater than the pressure sensitive voltage of ZnO varistor, ZnO varistor is connected automatically inhibits overvoltage.LCL filtering gird-connected inverter anti-overvoltage capacity and reliability can be improved in the utility model; effectively overvoltage caused by input overvoltage, output ground short circuit failure etc. can effectively be limited; and overcurrent caused by overvoltage can effectively be inhibited; and do not influence to protect normal operation circuit, to achieve the purpose that overvoltage protection.
Description
Technical field
The utility model relates to over-voltage protection technique field more particularly to a kind of LCL filtering gird-connected inverter protection electricity
Road.
Background technique
In order to reduce output harmonic wave content, usually increase filtering link in inverter output end, due in inductance size phase
Whens equal, LCL filtering has more preferably attenuation to electric current higher harmonic components, and when filter action is the same, needed for L filtering
Inductance total amount is greater than LCL type, improves material cost and bulking value, so that LCL filtering technique is using more and more extensive.So
And when ground short circuit failure occurs for LCL filtering parallel network reverse, but there is even more serious overvoltage problem, generation it is excessively electric
All there is serious threat safely to the electronic power switch device of inverters and LCL filter itself in pressure.
Currently, parallel connection buffer circuit but is worked as generally on electronic power switch device with limiting inverter internal overvoltage
LCL filters situations such as output ground short circuit failure occurs for gird-connected inverter when there is exterior overvoltage, and buffer circuit exists not
It is enough the problem of effectively limiting this exterior overvoltage.
Utility model content
In order to go out situations such as overcoming the above-mentioned filtering of LCL in the prior art gird-connected inverter that output ground short circuit failure occurs
When existing exterior overvoltage, the problem of buffer circuit Shortcomings are effectively to limit this exterior overvoltage, the utility model is provided
A kind of LCL filters gird-connected inverter over-voltage protection method, and the technical solution adopted in the utility model is:
A kind of LCL filtering gird-connected inverter protection circuit, including inverter and filter,
Wherein the inverter include four inverters being mutually electrically coupled together electronic power switch S1~
S4；
Filter is LCL filter, including inverter outlet side inductance L1, grid side inductance L2 and filter capacitor C1, institute
The input terminal that inverter outlet side inductance L1 is set to the LCL filter is stated, the grid side inductance L2 is set to the LCL
The output end of filter；
The inverter outlet side inductance L1 of the input terminal of the LCL filter is coupled to the inverter, the LCL filtering
The grid side inductance L2 of the output end of device is coupled to power grid；
The electronic power switch S1 is parallel with resistance Z2, and S2 is parallel with resistance Z3, and S3 is parallel with resistance Z4, and S4 is in parallel
There is resistance Z5, the input terminal of inverter is parallel with resistance Z1, and the output end of inverter is parallel with resistance Z8, the output end of filter
It is parallel with resistance Z6, filter capacity end is parallel with resistance Z7.
LCL filtering gird-connected inverter protection circuit provided by the utility model is whole using electronic power switch and inverter
Dual overvoltage protection strategy, a set of ZnO varistor of each switch designs is protected, meanwhile, and entire inversion
Device is as protected object, in inverter input/output terminal difference a set of ZnO varistor in parallel, when overvoltage is pressure-sensitive greater than ZnO
When the pressure sensitive voltage of resistance, ZnO varistor is connected automatically inhibits overvoltage.
The inverter is single-phase or three-phase.
The voltage at the varistor both ends when pressure sensitive voltage of the ZnO varistor refers to through 1mA electric current.
A set of ZnO varistor is arranged in inverter input terminal, is connected in parallel between DC bus anode and cathode, works as input terminal
When there is overvoltage, directly inhibited for the overvoltage to input terminal.
When occurring to export ground short circuit failure, since earth short circuit current is very big, it is big that electronic power switch cut-offs this
Serious overvoltage can be generated when electric current, therefore in each electronic power switch both ends of inverter a set of ZnO varistor in parallel
To form direct protection to power electronics.The residual voltage of varistor can increase with the electric current for flowing through varistor and be increased, when
When input overvoltage is excessive, the residual voltage of input terminal varistor may be greater than the withstanding voltage of electronic power switch, once this
When residual voltage is greater than the pressure sensitive voltage of ZnO varistor in parallel on electronic power switch, ZnO varistor conducting carries out residual voltage
Inhibit, the upper ZnO varistor in parallel of the switch ZnO varistor in parallel with inverter input terminal constitutes input overvoltage at this time
Duplicate protection.
Filter output a set of ZnO varistor in parallel, directly carries out overvoltage protection to inverter output end.Inversion
Device output end a set of ZnO varistor in parallel, protects parallel network reverse together with the ZnO varistor of filter output parallel connection
Device, prevent and net side because short trouble, voltage ripple of power network, lightning stroke intrusion etc. caused by overvoltage inverter is damaged.
ZnO varistor in parallel and the ZnO varistor of output end parallel connection constitute the double of the exterior overvoltages such as lightning stroke intrusion on switch
It protects again.
Filter capacity both ends a set of ZnO varistor in parallel, for protecting filter capacitor and preventing and net side is excessively electric
Pressure.Due to the presence of filter inductance, when short trouble occurs, the quick variation of electric current can induce biggish overvoltage, the mistake
Voltage may constitute a threat to filter capacitor.
Preferably, the ZnO varistor residual voltage being connected in parallel on electronic power switch will be opened with the power electronics
It closes voltage class to match, it is desirable that residual voltage cannot be greater than electronic power switch voltage class.
Preferably, the ZnO varistor residual voltage for being connected in parallel on filter capacitor will match with the filter capacitor pressure resistance
It closes, it is desirable that residual voltage cannot be greater than the resistance to voltage levels of filter capacitor.
Preferably, in order to improve overvoltage protection ability, overcome the specified ceiling capacity of existing single ZnO varistor and
The limitation of heat-sinking capability, every suit ZnO varistor can be composed in parallel by multiple same model ZnO varistors, to mention
High throughflow ability and specified maximum energy value.
Preferably, the electronic power switch is IGBT.
Compared with prior art, the beneficial effect of technical solutions of the utility model is:
LCL filtering gird-connected inverter anti-overvoltage capacity and reliability can be improved in the utility model, can be effectively by input
Overvoltage caused by overvoltage, output ground short circuit failure etc. is effectively limited, and can to overcurrent caused by overvoltage into
Row is effective to be inhibited, and does not influence to protect normal operation circuit, to achieve the purpose that overvoltage protection.
Detailed description of the invention
Fig. 1 is a kind of LCL filtering gird-connected inverter protection circuit circuit diagram provided by the utility model；
Fig. 2 is that electronic power switch over-voltage waveform is illustrated when output ground short circuit failure occurs for single-phase grid-connected inverter
Figure；
Fig. 3 is that IGBT single-phase full bridge LCL filtering gird-connected inverter overvoltage protection effect is shown in the utility model embodiment 2
It is intended to；
Wherein, S1 ~ S4 is electronic power switch, and Z1 ~ Z8 is ZnO varistor, and L1 is inverter side filter inductance, and L2 is simultaneously
Net side filter inductance, C1 are filter capacitor, and f is that point occurs for output ground short circuit failure.
Specific embodiment
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
It clearly and completely describes, it is clear that the described embodiments are only a part of the embodiments of the utility model, being given for example only property
Illustrate, should not be understood as the limitation to this patent.Based on the embodiments of the present invention, those of ordinary skill in the art are not having
Every other embodiment obtained under the premise of creative work is made, is fallen within the protection scope of the utility model.
The technical solution of the utility model is described further with reference to the accompanying drawings and examples.
Embodiment 1
A kind of LCL filtering gird-connected inverter protection circuit, including inverter and filter,
Wherein the inverter include four inverters being mutually electrically coupled together electronic power switch S1~
S4；
Filter is LCL filter, including inverter outlet side inductance L1, grid side inductance L2 and filter capacitor C1, institute
The input terminal that inverter outlet side inductance L1 is set to the LCL filter is stated, the grid side inductance L2 is set to the LCL
The output end of filter；
The inverter outlet side inductance L1 of the input terminal of the LCL filter is coupled to the inverter, the LCL filtering
The grid side inductance L2 of the output end of device is coupled to power grid；
The electronic power switch S1 is parallel with resistance Z2, and S2 is parallel with resistance Z3, and S3 is parallel with resistance Z4, and S4 is in parallel
There is resistance Z5, the input terminal of inverter is parallel with resistance Z1, and the output end of inverter is parallel with resistance Z8, the output end of filter
It is parallel with resistance Z6, filter capacity end is parallel with resistance Z7.
LCL filtering gird-connected inverter protection circuit provided by the utility model is whole using electronic power switch and inverter
Dual overvoltage protection strategy, a set of ZnO varistor of each switch designs is protected, meanwhile, and entire inversion
Device is as protected object, in inverter input/output terminal difference a set of ZnO varistor in parallel, when overvoltage is pressure-sensitive greater than ZnO
When the pressure sensitive voltage of resistance, ZnO varistor is connected automatically inhibits overvoltage.
Embodiment 2
LCL filtering gird-connected inverter protection circuit provided in this embodiment uses single-phase full bridge inverter bridge, converter bridge switching parts
Using IGBT(insulated gate bipolar transistor Insulated Gate Bipolar Transistor), filter is LCL type filter
Wave.
Fig. 2 is that electronic power switch over-voltage waveform is illustrated when output ground short circuit failure occurs for single-phase grid-connected inverter
Figure, a moment occur to export ground short circuit failure, will appear several times higher than normal operating voltage or even several on electronic power switch
Ten times of overvoltage.
When overvoltage occurs in inverter input terminal, ZnO varistor Z1, which is first turned on, inhibits overvoltage.If
Overvoltage pair is worth and excessive causes ZnO varistor Z1 residual voltage to be greater than to be connected in parallel on any ZnO varistors of IGBT switch ends
The pressure sensitive voltage of Z2-Z5, corresponding varistor inhibit conducting to overvoltage, to form duplicate protection to IGBT.
When output ground short circuit failure occurs for inverter f point, since earth short circuit current is very big, electronic power switch is opened
Serious overvoltage can be generated when this high current of breaking, once any varistor Z2-Z5 both end voltage of ZnO is greater than pressure sensitive voltage,
Corresponding ZnO varistor is connected immediately inhibits overvoltage, so that IGBT be protected to cause from output ground short circuit failure
Overvoltage injury.Meanwhile when the overvoltage that circuit occurs is greater than the pressure sensitive voltage of ZnO varistor Z6, Z7, Z8, Z6,
Z7, Z8 are connected automatically inhibits overvoltage.Fig. 3 is that 1 IGBT single-phase full bridge LCL of the utility model embodiment filtering is grid-connected
Inverter overvoltage protection effect diagram.
Obviously, the above embodiments of the present invention is merely examples for clearly illustrating the present invention, and
It is not limitations of the embodiments of the present invention.For those of ordinary skill in the art, in above description
On the basis of can also make other variations or changes in different ways.There is no need and unable to give all embodiments
Exhaustion.Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention etc., should be included in
Within the protection scope of the utility model claims.
Claims (4)
1. a kind of LCL filtering gird-connected inverter protects circuit, including inverter and filter,
Wherein the inverter includes the electronic power switch S1~S4 of four inverters being mutually electrically coupled together；
Filter is LCL filter, including inverter outlet side inductance L1, grid side inductance L2With filter capacitor C1, the inversion
Device outlet side inductance L1It is set to the input terminal of the LCL filter, the grid side inductance L2It is set to the LCL filter
Output end；
The inverter outlet side inductance L of the input terminal of the LCL filter1It is coupled to the inverter, the LCL filter
The grid side inductance L of output end2It is coupled to power grid；
It is characterized by: the electronic power switch S1 is parallel with resistance Z2, S2 is parallel with resistance Z3, and S3 is parallel with resistance
Z4, S4 are parallel with resistance Z5, and the input terminal of inverter is parallel with resistance Z1, and the output end of inverter is parallel with resistance Z8, filtering
The output end of device is parallel with resistance Z6, and filter capacity end is parallel with resistance Z7.
2. LCL according to claim 1 filtering gird-connected inverter protects circuit, which is characterized in that the inverter is
Single-phase or three-phase.
3. LCL according to claim 1 filtering gird-connected inverter protects circuit, which is characterized in that the resistance includes
Multiple same model ZnO varistors are in parallel.
4. LCL filtering gird-connected inverter according to claim 1 protects circuit, which is characterized in that the power electronics
Switch S1~S4 is IGBT.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821534355.9U CN209267432U (en) | 2018-09-19 | 2018-09-19 | A kind of LCL filtering gird-connected inverter protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821534355.9U CN209267432U (en) | 2018-09-19 | 2018-09-19 | A kind of LCL filtering gird-connected inverter protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN209267432U true CN209267432U (en) | 2019-08-16 |
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|---|---|---|---|
| CN201821534355.9U Active CN209267432U (en) | 2018-09-19 | 2018-09-19 | A kind of LCL filtering gird-connected inverter protection circuit |
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| Country | Link |
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| CN (1) | CN209267432U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109149918A (en) * | 2018-09-19 | 2019-01-04 | 广东电网有限责任公司 | A kind of LCL filtering gird-connected inverter protection circuit |
| CN113872433A (en) * | 2021-10-15 | 2021-12-31 | 青岛鼎信通讯股份有限公司 | Topology for improving anti-surge capacity of LCL type grid-connected inverter |
-
2018
- 2018-09-19 CN CN201821534355.9U patent/CN209267432U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109149918A (en) * | 2018-09-19 | 2019-01-04 | 广东电网有限责任公司 | A kind of LCL filtering gird-connected inverter protection circuit |
| CN109149918B (en) * | 2018-09-19 | 2024-10-01 | 广东电网有限责任公司 | LCL filtering grid-connected inverter protection circuit |
| CN113872433A (en) * | 2021-10-15 | 2021-12-31 | 青岛鼎信通讯股份有限公司 | Topology for improving anti-surge capacity of LCL type grid-connected inverter |
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