CN116845894A - High-pass filter - Google Patents
High-pass filter Download PDFInfo
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- CN116845894A CN116845894A CN202311108396.7A CN202311108396A CN116845894A CN 116845894 A CN116845894 A CN 116845894A CN 202311108396 A CN202311108396 A CN 202311108396A CN 116845894 A CN116845894 A CN 116845894A
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- 238000004804 winding Methods 0.000 claims abstract description 104
- 239000003990 capacitor Substances 0.000 claims abstract description 15
- 238000001914 filtration Methods 0.000 claims abstract description 15
- 230000001131 transforming effect Effects 0.000 claims abstract description 4
- 230000006698 induction Effects 0.000 abstract description 9
- 230000005540 biological transmission Effects 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000013461 design Methods 0.000 abstract description 2
- 230000000694 effects Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/01—Arrangements for reducing harmonics or ripples
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/2823—Wires
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/0153—Electrical filters; Controlling thereof
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Filters And Equalizers (AREA)
Abstract
The application relates to the technical field of flexible power transmission, and discloses a high-pass filter, which comprises: the multi-winding transformer comprises a multi-winding transformer body and a filter circuit, wherein the first winding of the multi-winding transformer body inputs electric quantity to be filtered, the second winding of the multi-winding transformer body outputs the filtered electric quantity, and the third winding of the multi-winding transformer body is connected with the filter circuit; the third winding is connected in series with the filter circuit to form a high-pass filter; the multi-winding transformer is used for transforming the electric quantity to be filtered. Compared with the traditional high-pass filter, the application adds the induction transformer with special design, realizes high-pass filtering, effectively reduces the electric stress requirement of the filter capacitor in the filter, and is beneficial to reducing the volume of the device and the cost of the device.
Description
Technical Field
The application relates to the technical field of flexible power transmission, in particular to a high-pass filter.
Background
With the development of new energy power generation and flexible power transmission technologies, the application of power electronic devices in power grids is also becoming more and more widespread. The power electronic device is used as a harmonic source, and higher harmonic wave output to the power grid can influence the power quality of the power grid, cause high-frequency resonance and possibly generate large high-frequency resonance current. The high frequency tolerance of conventional devices in the power grid is very limited, and the large high frequency resonant current may directly cause damage to the corresponding devices in the power grid.
Increasing the switching frequency of the power electronics device can effectively reduce harmonic output, but will result in increased cost of the device, and as the number of actions per unit time increases, the loss of the switching device will also increase greatly, adding additional volume and cost. The passive filter is additionally arranged at the grid-connected position of the power electronic device to play a role in filtering, but for a power system with higher voltage level, the filter needs to bear very high voltage, the required capacity rises along with the rise, the size of the traditional filter can be directly caused to be far larger than that of the power electronic device, and the problems of high cost and high loss of the filter are difficult to effectively solve.
Disclosure of Invention
In view of the above, the application provides a high-pass filter to solve the problems of high voltage stress, large capacity, large volume and high cost of the traditional passive filter.
The present application provides a high pass filter comprising: the multi-winding transformer comprises a multi-winding transformer body and a filter circuit, wherein the first winding of the multi-winding transformer body inputs electric quantity to be filtered, the second winding of the multi-winding transformer body outputs the filtered electric quantity, and the third winding of the multi-winding transformer body is connected with the filter circuit; the third winding is connected in series with the filter circuit to form a high-pass filter; the multi-winding transformer is used for transforming the electric quantity to be filtered.
Compared with the traditional high-pass filter, the application adds the induction transformer with special design, realizes high-pass filtering, effectively reduces the electric stress requirement of the filter capacitor in the filter, and is beneficial to reducing the volume of the device and the cost of the device.
In an alternative embodiment, the first winding is connected to the power electronics device and the second winding is connected to the power grid; the rated voltage of the first winding is matched with the output voltage level of the power electronic device; the rated voltage of the second winding is matched to the voltage of the power grid.
In an alternative embodiment, the third winding is a star connection or a delta connection.
In an alternative embodiment, the multi-winding transformer becomes a T-shaped structural circuit after being equivalent; the equivalent impedance of the first winding and the second winding is a positive value; the equivalent impedance of the third winding is positive, negative or 0.
In an alternative embodiment, the equivalent impedance of the third winding is adjusted by setting the impedance percentage between the windings of the multi-winding transformer.
In an alternative embodiment, the equivalent impedance of the third winding is adjusted by setting the number of turns of the third winding.
In an alternative embodiment, the filter circuit includes: a filter capacitor.
In an alternative embodiment, the capacitance of the filter capacitor is a fixed value or is adjustable.
In an alternative embodiment, the third winding is grounded through the filter circuit and the grounding circuit in sequence.
In an alternative embodiment, the ground circuit includes: ground impedance.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present application, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a block diagram of a high-pass filter according to an embodiment of the present application;
FIG. 2 is a block diagram of another high pass filter according to an embodiment of the present application;
FIG. 3 is a specific circuit topology of a high pass filter according to an embodiment of the present application;
fig. 4 is an equivalent circuit diagram of a high pass filter according to an embodiment of the present application;
fig. 5 is a block diagram of another high pass filter according to an embodiment of the present application;
fig. 6 is a verification example of a high pass filter according to an embodiment of the application;
FIG. 7 is a graph of high pass filter impedance versus frequency according to an embodiment of the present application;
FIG. 8 is a graph of waveforms of the grid-connected current and the grid-connected voltage without any filtering measures according to an embodiment of the present application;
FIG. 9 is a graph of the waveforms of the grid-connected current and the grid-connected voltage when the high pass filter is used according to the embodiment of the application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In order to solve the problems, the embodiment of the application provides a transformer induction type high-pass filter which can effectively solve the problems of high voltage stress, large capacity, large volume, high cost and the like of the traditional passive filter while reducing the harmonic wave input into a power grid by a power electronic device.
According to an embodiment of the present application, there is provided a high-pass filter, as shown in fig. 1, including: the multi-winding transformer 1 and the filter circuit 2, wherein the first winding 11 of the multi-winding transformer 1 inputs the electric quantity to be filtered, the second winding 12 outputs the filtered electric quantity, and the third winding 13 is connected with the filter circuit 2; the third winding 13 is connected in series with the filter circuit 2 to form a high-pass filter; the multi-winding transformer 1 is used for transforming the electric quantity to be filtered.
Specifically, the equivalent inductance of the third winding 13 and the filter circuit 2 of the present embodiment constitute an LCL filter, and a high-pass filter is constructed by setting parameters of the LCL filter.
In some alternative embodiments, as shown in fig. 2, the first winding 11 is connected to the power electronics and the second winding 12 is connected to the grid; the rated voltage of the first winding 11 matches the output voltage level of the power electronics; the rated voltage of the second winding 12 is matched with the voltage of the power grid, that is, the multi-winding transformer 1 of the embodiment not only can realize band-pass filtering but also has the function of boosting or reducing voltage, so that the rated voltages of the first winding 11 and the second winding 12 need to be matched with the voltage of the connected equipment.
In some alternative embodiments, the third winding 13 is a star connection or a delta connection.
Specifically, in this embodiment, the connection mode of the first winding 11 is not limited, and is connected to the power grid; the second winding 12 is connected with the power electronic device in an unlimited wiring mode, and the third winding 13 is connected with the filter circuit 2 in a star connection or a corner connection mode.
In some alternative embodiments, as shown in fig. 3, the filter circuit 2 includes: and a filter capacitor C. The capacitance of the filter capacitor C is a fixed value or adjustable.
Specifically, as shown in fig. 4, the multi-winding transformer 1 becomes a T-shaped structure circuit after being equivalent, and the equivalent impedance of the first winding 11 and the second winding 12 is positive; is positive (inductive), negative, or 0 (capacitive), but the absolute value of the fundamental frequency should not exceed the absolute value X of the equivalent impedance of the fundamental frequency of the filter capacitor C c 2% of (2%). In this way, the 1 st branch and the 2 nd branch in fig. 4 show inductance, and form an equivalent LCL filter together with the 3 rd branch showing capacitance, so that the high-pass filtering function is achieved, and high-frequency harmonic waves in the grid-connected current Igrid and the grid-connected point voltage Ugrid of the power electronic device are reduced.
In some alternative embodiments, there are two ways of adjusting the equivalent impedance for the third winding 13:
(1) The equivalent impedance of the third winding 13 is adjusted by setting the impedance percentage between the windings of the multi-winding transformer 1.
(2) The equivalent impedance of the third winding 13 is adjusted by setting the number of turns of the third winding 13.
In some alternative embodiments, as shown in fig. 5, the high pass filter further comprises: the third winding 13 is grounded through the filter circuit 2 and the grounding circuit 3 in order. The grounding circuit 3 includes: ground impedance.
Illustratively, the system shown in fig. 6 was used for the filtering effect test of the transformer inductive high pass filter. In fig. 6, the grid voltage level is 10 kV; the power electronic device is a three-phase STATCOM converter valve, and the switching frequency is 2700 and Hz; the induction transformer tertiary winding 13 rated at 1 kV, other parameters were set as follows:
(1) The rated voltage of each winding of the multi-winding transformer 1 is set according to actual requirements, and the rated voltage of the first winding 11 is considered to be the output voltage level of the converter valve; the rated voltage of the second winding 12 should be matched to the grid voltage; the nominal voltage of the tertiary winding 13 should minimize the filter volume, as allowed by the practical manufacturing level, such as insulation distance, device volume, etc.
(2) Percentage of impedance X between the second winding 12 and the first winding 11 of the induction transformer 21% =18% of the impedance between the second winding 12 and the third winding 13, percentage X 23% 12%, the impedance percentage between the first winding 11 and the third winding 13 is X 13% The method is obtained according to calculation, and the specific calculation process is as follows:
determining equivalence X on 3 rd branch of three-winding filter 3 Is herein defined as X 3 =0, X 3 、X 21% 、X 23% The following formula is substituted:
（1）
solving to obtain X 13% =6%。
Above is by fixing X 21% 、X 23% Numerical value, find X 13% In (2), let X 3 Is a specified value. Likewise, by fixing X 21% 、X 13% Or fix X 23% 、X 13% In (2), let X 3 Is a specified value; the third winding 13 of the induction transformer can be also arranged to have variable winding turns to dynamically adjust X 3 Is of a size of (a) and (b).
A filter capacitor C with the capacitance value of 550uF is selected, and the parasitic inductance of the capacitor at high frequency is ensured to be small. The impedance of the high pass filter is plotted as a function of frequency at this time as shown in fig. 7. It can be seen that the filter exhibits very low impedance values at 2300 Hz and above, at which time the harmonics of 2300 Hz and above frequency output from the converter valve do not substantially flow into the grid, all into the third winding 13 of the filter. If the filtering effect is to be ensured, the capacitance value of the capacitor can be set to be adjustable, and the filtering effect on the high frequency band is ensured by dynamically adjusting the capacitance value of the capacitor.
When no filtering measures are adopted, the network-in current (upper) and the grid-connected voltage (lower) are measured as shown in fig. 8, and when no filter is adopted, the voltage and the current input into the power grid by the converter valve have large harmonic components, which are not standard sine waveforms.
After the transformer induction type high-pass filter with the parameters is additionally arranged between the converter valve and the power grid, the network access current (upper) and the network connection voltage (lower) are measured again, and compared with fig. 8, the filter effect is obvious as shown in fig. 9. Fourier analysis is performed on the pre-filtering and post-filtering network access current to obtain a high-frequency current as follows:
the effect of the high-pass filter is obvious, the harmonic current of 2550 to 2850 and Hz on-line is obviously reduced, if the traditional filter is installed, the filter capacitor C needs to bear 10 kV voltage, the device is directly large in size, and the filter capacitor C in the induction type high-pass filter provided by the application only needs to bear 1 kV voltage, and higher harmonic waves can be filtered obviously, so that the economy and the effectiveness of the induction type high-pass filter provided by the application are further proved.
Although embodiments of the present application have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the application, and such modifications and variations fall within the scope of the application as defined by the appended claims.
Claims (10)
1. A high pass filter, comprising: a multi-winding transformer and a filter circuit, wherein,
the first winding of the multi-winding transformer inputs the electric quantity to be filtered, the second winding of the multi-winding transformer outputs the electric quantity after the filtering, and the third winding of the multi-winding transformer is connected with the filtering circuit;
the third winding is connected with the filter circuit in series to form a high-pass filter;
the multi-winding transformer is used for transforming the electric quantity to be filtered.
2. A high pass filter as defined in claim 1, wherein,
the first winding is connected with a power electronic device, and the second winding is connected with a power grid;
the rated voltage of the first winding is matched with the output voltage level of the power electronic device;
the rated voltage of the second winding is matched to the voltage of the power grid.
3. The high pass filter of claim 1, wherein the third winding is a star connection or a delta connection.
4. A high pass filter as defined in claim 1, wherein,
the multi-winding transformer is equivalent and then becomes a T-shaped structure circuit;
the equivalent impedance of the first winding and the second winding is a positive value;
the equivalent impedance of the third winding is a positive value, a negative value or 0.
5. The high-pass filter of claim 4, wherein,
the equivalent impedance of the third winding is adjusted by setting the impedance percentage between the windings of the multi-winding transformer.
6. The high-pass filter of claim 4, wherein,
and adjusting the equivalent impedance of the third winding by setting the number of turns of the third winding.
7. The high pass filter of claim 1, wherein the filtering circuit comprises: a filter capacitor.
8. The high-pass filter of claim 7, wherein,
the capacitance value of the filter capacitor is a fixed value or adjustable.
9. The high pass filter of claim 1, further comprising:
the third winding is grounded through the filter circuit and the grounding circuit in sequence.
10. The high pass filter of claim 9, wherein the ground circuit comprises: ground impedance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311108396.7A CN116845894A (en) | 2023-08-30 | 2023-08-30 | High-pass filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311108396.7A CN116845894A (en) | 2023-08-30 | 2023-08-30 | High-pass filter |
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| CN116845894A true CN116845894A (en) | 2023-10-03 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202311108396.7A Pending CN116845894A (en) | 2023-08-30 | 2023-08-30 | High-pass filter |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101557116A (en) * | 2009-02-26 | 2009-10-14 | 湖南大学 | Environment-friendly and energy-saving DC power station |
| CN101662220A (en) * | 2009-10-01 | 2010-03-03 | 湖南大学 | Voltage source type filter converter |
| EP2164159A1 (en) * | 2008-09-12 | 2010-03-17 | Vestas Wind Systems A/S | Low-voltage harmonic filter for full-scale converter systems |
| CN101995528A (en) * | 2010-09-29 | 2011-03-30 | 上海海事大学 | Compound power filter test device and method |
| CN103296919A (en) * | 2013-06-28 | 2013-09-11 | 中铝华大科技股份有限公司 | Three-phase two-pulse-wave high-power pulse current power supply for electrolytic cells and power supplying method |
| CN103501005A (en) * | 2013-09-30 | 2014-01-08 | 国网湖南省电力公司 | Transformer induction filtering and reactive compensation integration device suitable for wind power |
| CN104953591A (en) * | 2015-07-21 | 2015-09-30 | 海南金盘电气有限公司 | LLCL type filter based on three-winding transformer |
-
2023
- 2023-08-30 CN CN202311108396.7A patent/CN116845894A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2164159A1 (en) * | 2008-09-12 | 2010-03-17 | Vestas Wind Systems A/S | Low-voltage harmonic filter for full-scale converter systems |
| CN101557116A (en) * | 2009-02-26 | 2009-10-14 | 湖南大学 | Environment-friendly and energy-saving DC power station |
| CN101662220A (en) * | 2009-10-01 | 2010-03-03 | 湖南大学 | Voltage source type filter converter |
| CN101995528A (en) * | 2010-09-29 | 2011-03-30 | 上海海事大学 | Compound power filter test device and method |
| CN103296919A (en) * | 2013-06-28 | 2013-09-11 | 中铝华大科技股份有限公司 | Three-phase two-pulse-wave high-power pulse current power supply for electrolytic cells and power supplying method |
| CN103501005A (en) * | 2013-09-30 | 2014-01-08 | 国网湖南省电力公司 | Transformer induction filtering and reactive compensation integration device suitable for wind power |
| CN104953591A (en) * | 2015-07-21 | 2015-09-30 | 海南金盘电气有限公司 | LLCL type filter based on three-winding transformer |
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