CN102299517B - Industrial harmonic-eliminating filtering energy-saving device and method - Google Patents
Industrial harmonic-eliminating filtering energy-saving device and method Download PDFInfo
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- CN102299517B CN102299517B CN2011102687170A CN201110268717A CN102299517B CN 102299517 B CN102299517 B CN 102299517B CN 2011102687170 A CN2011102687170 A CN 2011102687170A CN 201110268717 A CN201110268717 A CN 201110268717A CN 102299517 B CN102299517 B CN 102299517B
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Abstract
The invention relates to an industrial harmonic-eliminating filtering energy-saving device and an industrial harmonic-eliminating filtering energy-saving method. The device comprises a harmonic and surge absorbing and rectifying circuit, an energy storage circuit, an inversion circuit, a power grid voltage phase and a frequency tracking circuit. Harmonic and surge signals and the like in a power grid are taken out and rectified by the rectifying circuit, and the rectified signals are sent to the energy storage circuit, namely the energy storage circuit is charged; the rectifying circuit and the energy storage circuit absorb the harmonic and surge signals and the like generated by industrial electric equipment on the power grid in the energy storage circuit; and when the energy storage circuit is saturated, the inversion circuit releases saturated energy in the energy storage circuit, is needed to track the frequency and phase of power grid voltage when releasing the energy, and releases energy under the conditions of the same frequency and the same phase, so that the industrial harmonic-eliminating filtering energy-saving device can eliminate harmonic and fulfill the aim of saving energy.
Description
Technical field
The invention belongs to the power grid control equipment in the electrotechnics, particularly relate to a kind of industrial harmonic-eliminating filtering energy saver and method thereof.
Background technology
Electric energy is the most widely used energy of modern society, and the development of modern industry has brought the contradiction between the decline of the electrical network quality of power supply and the high-quality power requirement.On the one hand, because the popularization of power-saving technology and automatic technology, the access of the nonlinear disturbance loads such as various power electronic equipments is increasing, the demand of electric energy is increased day by day, and inevitably the higher harmonic current that produces is injected electrical network in a large number, cause phenomenons such as grid voltage waveform distortion, voltage flicker, interference, caused the quality of power supply increasingly to worsen; On the other hand, because the needs of Development of Power Electronic Technology, the sensitive load equipment such as various chip manufacturings, precise machining equipment such as frequency-changing speed-regulating driver, robot, automatic assembly line, Programmable Logic Controller, computer information system have not only proposed more strict requirement to power supply qualitys such as supply power voltage interruption, flickering and harmonic contents, and very responsive to fluctuation and the external interference of power supply.The deterioration of any power supply quality all may cause the decline of product quality, causes great economic loss, and thus, electric harmonic becomes the subject matter of the quality of power supply.Mains by harmonics is mainly produced by nonlinear-load.Electric current and the non-linear relation of terminal voltage that nonlinear-load absorbs, as a result electric current generation wave distortion and cause the terminal voltage wave distortion.This periodic distorted waveform can be launched into the Fourier series form by fundamental frequency (50Hz), and its component greater than fundamental frequency is harmonic wave.Harmonic pollution is serious to the harm of electric power system and power consumption equipment, be mainly manifested in following several aspect: load of utility 1, increases electric power, reduce the system power factor, reduce available capacity and the efficient of generating, transmission of electricity and power consumption equipment, cause equipment waste, circuit waste and energy loss; 2, cause compensation capacitors resonance and amplified harmonic current, cause the capacitor group to damage maybe and can't put into operation because of overcurrent or overvoltage; 3, produce pulsating torque and cause motor vibration, affect product quality and electrical machinery life; 4, because eddy current and kelvin effect make motor, transformer, transmission line etc. produce the secondary power loss and overheated, the waste electric energy also accelerates ageing of insulation; 5, harmonic voltage has strengthened the electric field strength of dielectric with the form that is proportional to its crest voltage, reduces service life of equipment; 6,3 multiple subharmonic current can cause the center line overload of three-phase four wire system, and produces circulation in the Transformer Winding of delta connection, makes the winding current overrate, when serious even accidents caused.
Everyly have the ability to carry out the device that signal processes and to be called filter.In modern age telecommunication apparatus and all kinds of control system, filter is used very extensive; In all electronic units, use at most, what technology was the most complicated will calculate filter.The good and bad quality that directly determines product of filter, so, research and the production of filter are always paid attention to by various countries.The U.S. in 1917 and Germany scientist have been invented respectively the LC filter, and next year has caused the appearance of first multiplex system of the U.S..The 1950's, passive filter reached its maturity.From the sixties because the development of computer technology, integrated technique and material industry, the filter development steps on a new stage, and towards low-power consumption, high accuracy, small size, multi-functional, reliable and stable and inexpensive direction effort, wherein small size, multi-functional, high accuracy, the reliable and stable main direction that becomes after the seventies.Cause the develop rapidly of the various filters such as RC active filter, digital filter, switching capacity filter and transchanger, to the later stage seventies, the monolithic of above-mentioned several filters is integrated to be developed out and to be applied.The eighties, be devoted to the research of all kinds of Novel Filters, make great efforts to improve performance and enlarge gradually range of application.The nineties is to the development of now mainly being devoted to all kinds of filters are applied to various product.Certainly, the research of filter itself is still constantly being carried out.The kind of the existing filter of China and the frequency that covers satisfy existing various telecommunication apparatus basically.As a whole, China's active filter development is slower than passive filter, not yet a large amount of production and application.Can find out the applicable cases of all kinds of filters of China from following production application ratio: the LC filter accounts for 50%; Crystal filter accounts for 20%; Mechanical filter accounts for 15%; Pottery and SAW (Surface Acoustic Wave) filter respectively account for 1%; All the other all kinds of filters account for 13% altogether.From these application percentages, China's electronic product wants to realize large-scale integrated, the integrated important topic that remains of filter.Along with the development of electronics industry, more and more higher to the performance requirement of filter, function is also more and more, and requires them to integrated future development.China's filter research and production and above-mentioned requirements differ greatly, for shortening this gap, the inventor is based on being engaged in for many years abundant practical experience and professional knowledge of this type of product design manufacturing, and the utilization of cooperation scientific principle, positive research and innovation in addition, in the hope of founding a kind of industrial harmonic-eliminating filtering energy saver of new structure, can improve general existing industrial harmonic-eliminating filtering energy saver, make it have more practicality.Through constantly research, design, and after repeatedly studying sample and improvement, finally create the present invention who has practical value.
Summary of the invention
Main purpose of the present invention is that overcome existing filter and have following defective: the traditional passive filter is harmonic carcellation effectively, but harmonic energy is not fully used; The tradition active filter eliminates harmonic wave by the inverse injection energy, harmonic carcellation effectively, but need the outside that energy is provided, and loss own is larger, the invention provides a kind of industrial harmonic-eliminating filtering energy saver of new structure, and technical problem to be solved is not only to make it have the harmonic carcellation function, but also have harmonic energy is taken full advantage of function, have obvious energy-saving effect, thus more applicable, and have value on the industry.
The present invention compared with prior art has obvious advantage and beneficial effect.By above technical scheme as can be known, in order to reach aforementioned goal of the invention, main technical content of the present invention is as follows:
A kind of industrial harmonic-eliminating filtering energy saver comprises:
Harmonic wave, surge absoption rectification circuit are used for the signals such as the harmonic wave of electrical network and surge are taken out, and carry out rectification;
Accumulator is for the electric energy after storage harmonic wave, the rectification of surge absoption rectification circuit;
Inverter circuit is used for the electric energy that accumulator is saturated and discharges;
Electric network voltage phase, frequency tracking circuit, the frequency and the phase place that are used for following the tracks of line voltage reach the electric energy in the accumulator and line voltage together frequency, same-phase, thereby electric energy saturated in the accumulator are discharged by inverter circuit.
A kind of industrial harmonic-eliminating filtering power-economizing method, its step is as follows:
(1), by harmonic wave, surge absoption rectification circuit harmonic wave and surge are taken out from electrical network;
(2), by after the rectification with the power storage of the harmonic wave that takes out in the step (1) and surge in accumulator;
(3), by electric network voltage phase, frequency tracking circuit, with the electric energy in the accumulator, by inverter circuit with electrical network with frequently, homophase is discharged in the electrical network.
Aforesaid accumulator adopts capacitance energy storage,
Aforesaid electric network voltage phase, frequency tracking circuit comprise voltage signal acquisition circuit, microprocessor, drive circuit; Microprocessor is processed the electric energy in the accumulator by the information of voltage signal acquisition circuit, reaches and line voltage together frequency, same-phase, then sends to drive circuit.
The working power of aforesaid microprocessor is accumulator.
Aforesaid inverter circuit comprises H bridge circuit, output filter circuit, and the H bridge circuit is used for receiving the electric energy of electric network voltage phase, frequency tracking circuit drive circuit, is discharged in the electrical network by output filter circuit.
The working power of aforesaid H bridge circuit is accumulator.
The aforesaid industrial harmonic-eliminating filtering energy saver scope of application is 30-300KW, voltage 220-380VAC industrial electricity apparatus.
By technique scheme, the present invention has following advantages at least:
1, utilize accumulator that the harmonic wave that industrial electricity apparatus produces is absorbed in the accumulator.
2, when accumulator reaches capacity, give off energy, be that harmonic carcellation reaches again energy-conservation dual purpose like this.
3, traditional passive filter harmonic carcellation effectively, but harmonic energy is not fully used; The tradition active filter is by the inverse injection energy harmonic wave to be eliminated, harmonic carcellation effectively, but need the outside that energy is provided, and loss own is larger, the invention provides a kind of industrial harmonic-eliminating filtering energy saver of new structure, and technical problem to be solved is not only to make it have the harmonic carcellation function, but also have harmonic energy is taken full advantage of function, have obvious energy-saving effect, thus more applicable, and have value on the industry.
4, the present invention is energy-conservation from optimizing the approach such as design of electrical motor industry, reasonable selection, technological transformation, and its successful development will be filled up the technological gap of domestic electron trade.And this product large scale investment is produced, and can bring more job opportunity, promotes local expanding economy, has good economic benefit and social benefit.
In sum, the present invention has above-mentioned many advantages and practical value, and in like product, publish or use and really genus innovation there are no similar structural design, no matter it structurally or larger improvement is all arranged on the function, is had large improvement technically, and has produced handy and practical effect, and more existing filter has the multinomial effect of enhancement, thereby more being suitable for practicality, and having the extensive value of industry, really is a new and innovative, progressive, practical new design.
Above-mentioned explanation only is the general introduction of technical solution of the present invention, for can clearer understanding technological means of the present invention, and can be implemented according to the content of specification, below with preferred embodiment of the present invention and cooperate accompanying drawing to be described in detail as follows.
The specific embodiment of the present invention is provided in detail by following examples and accompanying drawing thereof.
Description of drawings
Fig. 1 is principle assumption diagram of the present invention;
Fig. 2 is electric network voltage phase, frequency tracking circuit principle assumption diagram;
Fig. 3 is electrical network inverter circuit principle assumption diagram.
Embodiment
Reach technological means and the effect that predetermined goal of the invention is taked for further setting forth the present invention, below in conjunction with accompanying drawing and preferred embodiment, industrial its embodiment of harmonic-eliminating filtering energy saver, structure, feature and effect thereof to foundation the present invention proposes are described in detail as follows.
As shown in Figure 1, a kind of industrial harmonic-eliminating filtering energy saver comprises:
Harmonic wave, surge absoption rectification circuit are used for the signals such as the harmonic wave of electrical network and surge are taken out, and carry out rectification;
Accumulator is for the electric energy after storage harmonic wave, the rectification of surge absoption rectification circuit;
Inverter circuit is used for the electric energy that accumulator is saturated and discharges;
Electric network voltage phase, frequency tracking circuit, the frequency and the phase place that are used for following the tracks of line voltage reach the electric energy in the accumulator and line voltage together frequency, same-phase, thereby electric energy saturated in the accumulator are discharged by inverter circuit.
Aforesaid accumulator adopts capacitance energy storage.
As shown in Figure 2, aforesaid electric network voltage phase, frequency tracking circuit comprise voltage signal acquisition circuit, microprocessor, drive circuit; Microprocessor is processed the electric energy in the accumulator by the information of voltage signal acquisition circuit, reaches and line voltage together frequency, same-phase, then sends to drive circuit.The working power of aforesaid microprocessor is accumulator.
As shown in Figure 3, aforesaid inverter circuit comprises H bridge circuit, output filter circuit, and the H bridge circuit is used for receiving the electric energy of electric network voltage phase, frequency tracking circuit drive circuit, is discharged in the electrical network by output filter circuit.The working power of aforesaid H bridge circuit is accumulator.
The aforesaid industrial harmonic-eliminating filtering energy saver scope of application is 30-300KW, voltage 220-380VAC industrial electricity apparatus.
As shown in Figure 1, a kind of industrial harmonic-eliminating filtering power-economizing method, its step is as follows:
(1), by harmonic wave, surge absoption rectification circuit harmonic wave and surge are taken out from electrical network;
(2), by after the rectification with the power storage of the harmonic wave that takes out in the step (1) and surge in accumulator;
(3), by electric network voltage phase, frequency tracking circuit, with the electric energy in the accumulator, by inverter circuit with electrical network with frequently, homophase is discharged in the electrical network.
The technological innovation of the present invention that above-mentioned structure like this consists of all has many saving graces for technical staff of the same trade now, and the progressive that really possesses skills.
The above, it only is preferred embodiment of the present invention, be not that the present invention is done any pro forma restriction, although the present invention discloses as above with preferred embodiment, yet be not to limit the present invention, any those skilled in the art, within not breaking away from the technical solution of the present invention scope, when the technology contents that can utilize above-mentioned announcement is made a little change or is modified to the equivalent embodiment of equivalent variations, in every case be the content that does not break away from technical solution of the present invention, any simple modification that foundation technical spirit of the present invention is done above embodiment, equivalent variations and modification all still belong in the scope of technical solution of the present invention.
Claims (8)
1. industrial harmonic-eliminating filtering energy saver is characterized in that comprising:
Harmonic wave, surge absoption rectification circuit are used for harmonic wave and the surging signal of electrical network are taken out, and carry out rectification;
Accumulator is for the electric energy after storage harmonic wave, the rectification of surge absoption rectification circuit;
Inverter circuit is used for the electric energy that accumulator is saturated and discharges;
Electric network voltage phase, frequency tracking circuit, the frequency and the phase place that are used for following the tracks of line voltage reach the electric energy in the accumulator and line voltage together frequency, same-phase, thereby electric energy saturated in the accumulator are discharged by inverter circuit.
2. industrial harmonic-eliminating filtering energy saver according to claim 1 is characterized in that wherein said accumulator adopts capacitance energy storage.
3. industrial harmonic-eliminating filtering energy saver according to claim 1 is characterized in that described electric network voltage phase, frequency tracking circuit comprise voltage signal acquisition circuit, microprocessor, drive circuit; Microprocessor is processed the electric energy in the accumulator by the information of voltage signal acquisition circuit, reaches and line voltage together frequency, same-phase, then sends to drive circuit.
4. industrial harmonic-eliminating filtering energy saver according to claim 3, the working power that it is characterized in that described microprocessor is accumulator.
5. industrial harmonic-eliminating filtering energy saver according to claim 1, it is characterized in that described inverter circuit comprises H bridge circuit, output filter circuit, the H bridge circuit is used for receiving the electric energy of electric network voltage phase, frequency tracking circuit drive circuit, is discharged in the electrical network by output filter circuit.
6. industrial harmonic-eliminating filtering energy saver according to claim 5, the working power that it is characterized in that described H bridge circuit is accumulator.
7. industrial harmonic-eliminating filtering energy saver according to claim 1 is characterized in that the described industrial harmonic-eliminating filtering energy saver scope of application is power 30-300KW, voltage 220-380VAC industrial electricity apparatus.
8. industrial harmonic-eliminating filtering power-economizing method, its step is as follows:
(1), by harmonic wave, surge absoption rectification circuit harmonic wave and surge are taken out from electrical network;
(2), by after the rectification with the power storage of the harmonic wave that takes out in the step (1) and surge in accumulator;
(3), by electric network voltage phase, frequency tracking circuit, with the electric energy in the accumulator, by inverter circuit with line voltage with frequently, homophase is discharged in the electrical network.
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| CN2011102687170A CN102299517B (en) | 2011-09-13 | 2011-09-13 | Industrial harmonic-eliminating filtering energy-saving device and method |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5351180A (en) * | 1992-10-30 | 1994-09-27 | Electric Power Research Institute, Inc. | Highly fault tolerant active power line conditioner |
| CN2527016Y (en) * | 2002-01-11 | 2002-12-18 | 张玉良 | Hybrid reactive power generator |
| CN1832289A (en) * | 2006-03-24 | 2006-09-13 | 武汉大学 | Neutral harmonic current managing device and control method thereof |
| CN101604844A (en) * | 2009-07-06 | 2009-12-16 | 山东雷奇电器有限公司 | A kind of frequency converter for eliminating harmonic waves |
| CN201398174Y (en) * | 2009-03-31 | 2010-02-03 | 杭州金兰达科技有限公司 | Power saving device special for asynchronous motor |
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- 2011-09-13 CN CN2011102687170A patent/CN102299517B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5351180A (en) * | 1992-10-30 | 1994-09-27 | Electric Power Research Institute, Inc. | Highly fault tolerant active power line conditioner |
| CN2527016Y (en) * | 2002-01-11 | 2002-12-18 | 张玉良 | Hybrid reactive power generator |
| CN1832289A (en) * | 2006-03-24 | 2006-09-13 | 武汉大学 | Neutral harmonic current managing device and control method thereof |
| CN201398174Y (en) * | 2009-03-31 | 2010-02-03 | 杭州金兰达科技有限公司 | Power saving device special for asynchronous motor |
| CN101604844A (en) * | 2009-07-06 | 2009-12-16 | 山东雷奇电器有限公司 | A kind of frequency converter for eliminating harmonic waves |
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Owner name: SICHUAN DEFENG ELECTRIC CO., LTD. Free format text: FORMER OWNER: CHANGZHOU CAMPUS, HOHAI UNIVERSITY Effective date: 20131008 |
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Effective date of registration: 20131008 Address after: County Economic Development Zone Industrial Park of Guang'an City, Sichuan Province, wusheng County 638402 Patentee after: SICHUAN DEFENG ELECTRIC CO.,LTD. Address before: 213022 Jiangsu, North District, Changzhou Jin Ling North Road, No. 200 Patentee before: CHANGZHOU CAMPUS OF HOHAI University |