CN104764922A - Extraction method for three-phase network voltage positive-sequence components under imbalance condition - Google Patents
Extraction method for three-phase network voltage positive-sequence components under imbalance condition Download PDFInfo
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- CN104764922A CN104764922A CN201510108289.3A CN201510108289A CN104764922A CN 104764922 A CN104764922 A CN 104764922A CN 201510108289 A CN201510108289 A CN 201510108289A CN 104764922 A CN104764922 A CN 104764922A
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Abstract
The invention aims to provide an extraction method for three-phase network voltage positive-sequence components under an imbalance condition. The extraction method is high in speed, good in stability and low in requirement for the external hardware environment. Through combination of formula translation and a first-order inertial filtering method, a reasonable and effective positive-sequence separation method is provided and can meet the requirement for obtaining power network fundamental wave phase information through a current converter under the three-phase imbalance condition of a power network. Based on an ABC coordinate system, through performing detection operation and first-order inertial filtering on the instantaneous value of three-phase network voltage, the three-phase network voltage positive-sequence components are effectively extracted without converting under different coordinate systems; the algorithm is easier to implement in an embedded control system, and the requirement for the speed of an embedded processor is lower. The extraction method can be applied to the field of power electronics.
Description
Technical field
The present invention relates to field of power electronics---new-energy grid-connected type current transformer and electrokinetic cell discharge and recharge detect the control method of Bidirectional variable-flow equipment, the three-phase power grid voltage positive-sequence component extracting method under especially a kind of uneven condition.
Background technology
In the equipment such as new energy grid-connected power and electrokinetic cell discharge and recharge detection, in order to avoid impacting the quality of power supply, usually the voltage and current phase place of detection of grid is needed, when three-phase imbalance, conventional phase-lock technique is adopted to carry out phase-locked easy inefficacy to electrical network, therefore, in order to the balance of better carrying out three-phase current controls, need electrical network three-phase voltage to carry out positive sequence separation, by voltage positive-sequence component, grid phase is better followed the tracks of.
Positive sequence extracting method common at present can be divided into analytical method and filter method, analytical method refers to and utilizes limited sampled point to calculate positive-sequence component quickly and accurately by analytic methods such as trigonometric function differentiates, as instantaneous symmetrical components, analytical method speed but to harmonic wave or sudden change too responsive; Filter method, by filtering and obtain positive-sequence component again after coordinate transform, carries out the methods such as trap phaselocked loop after calculating based on Park conversion or instantaneous reactive, and the result that they obtain is comparatively steady, but speed is general, and comparatively analytical method is slow.Above-mentioned two kinds of methods can not have stability and feature fast concurrently simultaneously.
Summary of the invention
Technical matters to be solved by this invention overcomes the deficiencies in the prior art, aims to provide that a kind of speed is fast, good stability and outside hardware environment is required to the three-phase power grid voltage positive-sequence component extracting method under low uneven condition.
The technical solution adopted in the present invention is, the method comprises the following steps:
(1) by voltage hall sensor or resistance ratio network and amplifier modulate circuit isolation sampling three-phase electrical network instantaneous voltage
u a ,
u b ,
u c , when removing zero-sequence component, can following relationship be met:
Wherein
u ap ,
u bp ,
u cp represent respectively
u a ,
u b ,
u c the positive-sequence component of three-phase voltage,
u an ,
u bn ,
u cn represent respectively
u a ,
u b ,
u c the negative sequence component of three-phase voltage;
(2) will
u a ,
u b ,
u c carry out one order inertia filtering respectively, transport function is
, carry out digitalization operation for convenience within a processor, the digitizing discrete equation adopting difference equation to obtain one order inertia filtering is:
, wherein τ represents time constant filter,
trepresent the sampling time interval of processor to three-phase voltage, i represents sampling number;
(3) value obtained after step (2) filtering is established to be respectively
u a_lpf ,
u b_lpf ,
u c_lpf , can obtain through following formula
Wherein
u a_p ,
u b_p ,
u c_p corresponding with delayed
u a ,
u b ,
u c positive-sequence component phasing degree be 90 degree;
(4) value obtained in step (3) is carried out superposition fortune place, the value in the one-period obtained also is the Digital Discrete value in one-period vector.Carry out superposition by following formula can obtain
Finally obtain the three-phase power grid voltage positive-sequence component under uneven condition
u ap ,
u bp ,
u cp .
Further, in described step (2), output with the corresponding relation of input is: export with the amplitude size of input the same, phase angle is determined by following formula
, wherein
ω irepresent the angular frequency of input filter input signal.
Further, in described step (2), export the same with the amplitude size of input, delayed phase 60 degree.
Further, the calculating of described extracting method is all carry out based on digital processing unit, and calculates each control cycle being present in current transformer power switch pipe.
The invention has the beneficial effects as follows: the present invention is combined with one order inertia filter method by fortran, propose a kind of rationally effective positive sequence separation method, under can meeting electrical network three-phase imbalance situation, current transformer is to the acquisition of electrical network fundamental phase information; The present invention is based on ABC coordinate system by the detection calculations of three-phase power grid voltage instantaneous value and one order inertia filtering, effectively three-phase power grid voltage positive-sequence component is extracted, without the need to carrying out the conversion process under different coordinates, can easier implementation algorithm in embedded control system, lower to the rate request of flush bonding processor; So the inventive method is that a kind of speed is fast, good stability and outside hardware environment is required to the three-phase power grid voltage positive-sequence component extracting method under low uneven condition.
Embodiment
The present invention proposes the three-phase power grid voltage positive-sequence component extracting method under a kind of uneven condition, the method comprises the steps:
(1) by voltage hall sensor and amplifier modulate circuit isolation sampling three-phase electrical network instantaneous voltage
u a ,
u b ,
u c , when removing zero-sequence component, can following relationship be met:
Wherein
u ap ,
u bp ,
u cp represent respectively
u a ,
u b ,
u c the positive-sequence component of three-phase voltage,
u an ,
u bn ,
u cn represent respectively
u a ,
u b ,
u c the negative sequence component of three-phase voltage.
(2) will
u a ,
u b ,
u c carry out one order inertia filtering respectively, transport function is
, carry out digitalization operation for convenience within a processor, the digitizing discrete equation adopting difference equation to obtain one order inertia filtering is:
, wherein τ represents time constant filter,
trepresent the sampling time interval of processor to three-phase voltage, i represents sampling number.Export in this step and with the corresponding relation of input be, export the same with the amplitude size of input, delayed phase 60 degree, phase angle is determined by following formula:
, wherein
ω irepresent the angular frequency of input filter input signal, because line voltage is 50Hz, be therefore
ω isize is 100 π, and in order to meet the phase shift of delayed 60 degree, the value of timeconstantτ is about 0.0178;
(3) value obtained after step (2) filtering is established to be respectively
u a_lpf ,
u b_lpf ,
u c_lpf .Can obtain through following formula
Wherein
u a_p ,
u b_p ,
u c_p corresponding with delayed
u a ,
u b ,
u c positive-sequence component phasing degree be 90 degree;
(4) due to computing be above all to vector carry out discrete after digital manipulation, therefore the value obtained in step (3) is carried out superposition fortune place, the value in the one-period obtained also is the Digital Discrete value in one-period vector.Carry out superposition by following formula can obtain
Finally obtain the three-phase power grid voltage positive-sequence component under uneven condition
u ap ,
u bp ,
u cp .
The calculating of above-mentioned steps is all carry out in digital processing unit (DSP etc. as TI), and calculates each control cycle being present in current transformer power switch pipe.
The present invention is based on ABC coordinate system by the detection calculations of three-phase power grid voltage instantaneous value and one order inertia filtering, effectively three-phase power grid voltage positive-sequence component is extracted, without the need to carrying out the conversion process under different coordinates, can easier implementation algorithm in embedded control system, lower to the rate request of flush bonding processor.
The present invention can be applicable to field of power electronics.
Claims (4)
1. the three-phase power grid voltage positive-sequence component extracting method under uneven condition, it is characterized in that, the method comprises the following steps:
(1) by voltage hall sensor or resistance ratio network and amplifier modulate circuit isolation sampling three-phase electrical network instantaneous voltage
u a ,
u b ,
u c , when removing zero-sequence component, can following relationship be met:
Wherein
u ap ,
u bp ,
u cp represent respectively
u a ,
u b ,
u c the positive-sequence component of three-phase voltage,
u an ,
u bn ,
u cn represent respectively
u a ,
u b ,
u c the negative sequence component of three-phase voltage;
(2) will
u a ,
u b ,
u c carry out one order inertia filtering respectively, transport function is
, carry out digitalization operation for convenience within a processor, the digitizing discrete equation adopting difference equation to obtain one order inertia filtering is:
, wherein 7 represent time constant filter,
trepresent the sampling time interval of processor to three-phase voltage, i represents sampling number;
(3) value obtained after step (2) filtering is established to be respectively
u a_lpf ,
u b_lpf ,
u c_lpf , can obtain through following formula
Wherein
u a_p ,
u b_p ,
u c_p corresponding with delayed
u a ,
u b ,
u c positive-sequence component phasing degree be 90 degree;
(4) value obtained in step (3) is carried out superposition fortune place, the value in the one-period obtained also is the Digital Discrete value in one-period vector.Carry out superposition by following formula can obtain
Finally obtain the three-phase power grid voltage positive-sequence component under uneven condition
u ap ,
u bp ,
u cp .
2. the three-phase power grid voltage positive-sequence component extracting method under a kind of uneven condition according to claim 1, it is characterized in that, in described step (2), output with the corresponding relation of input is: export with the amplitude size of input the same, phase angle is determined by following formula
, wherein
ω irepresent the angular frequency of input filter input signal.
3. the three-phase power grid voltage positive-sequence component extracting method under a kind of uneven condition according to claim 2, is characterized in that: in described step (2), exports the same with the amplitude size of input, delayed phase 60 degree.
4. the three-phase power grid voltage positive-sequence component extracting method under a kind of uneven condition according to any one of claims 1 to 3, it is characterized in that: the calculating of described extracting method is all carry out based on digital processing unit, and calculate each control cycle being present in current transformer power switch pipe.
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| CN201510108289.3A CN104764922B (en) | 2015-03-12 | 2015-03-12 | A kind of three-phase power grid voltage positive-sequence component extracting method under the conditions of imbalance |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106771587A (en) * | 2016-11-29 | 2017-05-31 | 佛山市柏克新能科技股份有限公司 | A kind of extracting method of three-phase positive-sequence component |
| US9906162B2 (en) | 2016-04-29 | 2018-02-27 | Caterpillar Inc. | Method to control three-phase inverter voltage |
| CN109358228A (en) * | 2018-11-09 | 2019-02-19 | 哈工大（张家口）工业技术研究院 | The positive and negative order components real-time estimation method of network voltage based on double enhanced phaselocked loops |
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| US20050162170A1 (en) * | 2003-03-14 | 2005-07-28 | Antti Tarkiainen | Method for determining a negative sequence component |
| CN102590618A (en) * | 2012-03-05 | 2012-07-18 | 山西省电力公司晋城供电分公司 | Detection method of positive sequence voltage phase of fundamental wave for power grid |
| CN103472301A (en) * | 2013-09-30 | 2013-12-25 | 苏州大学 | Method and system for extracting positive sequence component and negative sequence component of network voltage |
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2015
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| US20050162170A1 (en) * | 2003-03-14 | 2005-07-28 | Antti Tarkiainen | Method for determining a negative sequence component |
| CN102590618A (en) * | 2012-03-05 | 2012-07-18 | 山西省电力公司晋城供电分公司 | Detection method of positive sequence voltage phase of fundamental wave for power grid |
| CN103472301A (en) * | 2013-09-30 | 2013-12-25 | 苏州大学 | Method and system for extracting positive sequence component and negative sequence component of network voltage |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9906162B2 (en) | 2016-04-29 | 2018-02-27 | Caterpillar Inc. | Method to control three-phase inverter voltage |
| CN106771587A (en) * | 2016-11-29 | 2017-05-31 | 佛山市柏克新能科技股份有限公司 | A kind of extracting method of three-phase positive-sequence component |
| CN109358228A (en) * | 2018-11-09 | 2019-02-19 | 哈工大（张家口）工业技术研究院 | The positive and negative order components real-time estimation method of network voltage based on double enhanced phaselocked loops |
| CN109358228B (en) * | 2018-11-09 | 2020-12-15 | 哈工大（张家口）工业技术研究院 | Power grid voltage positive and negative sequence component real-time estimation method based on double enhanced phase-locked loops |
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Address after: 519080 unit 606, 6 building, No. 99, University Road, Tangjia Bay, Zhuhai high tech Zone, Guangdong Patentee after: Zhuhai Unimax Power Electronic Technology Co. Ltd. Address before: 519000 Room 606, 1 building, 99 innovation base, Tangjia Bay Road, Zhuhai, Guangdong. Patentee before: Source, Hengqin, Zhuhai nine power electronics Science and Technology Ltd. |