CN104362655A - Unbalanced load compensation device and compensation method - Google Patents
Unbalanced load compensation device and compensation method Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention relates to a compensation device and a compensation method applied in microgrids and low-voltage power distribution grids, and in particular relates to an unbalanced load compensation device and an unbalanced load compensation method. The compensation method utilizing the compensation device comprises the following steps: carrying out real-time acquisition on the voltages and the currents of a power grid via digital signals; carrying out necessary filtering processing on power grid voltage and current signals acquired in real time, then sending the current signals acquired in real time into a three-two coordinate transformation system, transforming the current signals into a dq0 coordinate system and performing compensation calculation on the currents; returning a duty ratio obtained in a calculation manner into an abc coordinate system so as to perform real-time compensation, and carrying out single processing on a fourth bridge arm specially used for a zero line current, thereby realizing the purpose of real-time compensation of unbalanced loads. According to the method, the voltages and currents of the power grid and the real-time currents of an IGBT (Insulated Gate Bipolar Transistor) can be monitored and protected while the compensation of unbalanced loads is finished at the same time, and the signals acquired in real time are stored and processed.
Description
Technical field
The present invention relates to the compensation arrangement in electric power low-pressure distribution and method, be specially a kind of unbalanced load compensation arrangement and compensation method.
Background technology
In the existing traditional three-phase four-wire system distribution transformer wiring system of China, because low pressure single-phase load can not manually be divided equally completely, the not equal a variety of causes of load in-service factor of distribution, and cause three-phase load unbalance phenomenon to be inevitable.And this three-phase load unbalance phenomenon must cause loss increase, power consumption efficiency declines, zero-sequence current increases, shorten the useful life of equipment, time serious, power equipment cisco unity malfunction will be caused.
Harm to transformer: three-phase load unbalance will make transformer be in asymmetric operation state, thus cause the loss of transformer to increase.According to transformer operating standard regulation, the transformer neutral current be in operation can not exceed 25% of step down side rated current.In addition, three-phase load unbalance can cause transformer zero-sequence current excessive, and part metals part heats up to be increased, and even causes transformer to burn.The neutral line and neutral point voltage problem: neutral line zero-sequence current is excessive, cause the neutral line to burn, and causes neutral point voltage to offset the problems such as excessive.Harm to power consumption equipment: three-phase load unbalance will make inverse moment of torsion in motor increase, thus cause motor to heat up, decrease in efficiency, the phenomenons such as energy consumption increase.Therefore the imbalance of three-phase load can cause power consumption equipment shortening in useful life, and acceleration equipment part replacement frequency, increases cost of equipment maintenance.The split-phase reactive power compensation device that compensation effect is best in the market compensates load, also the reactive current components in system can only be mended, and it is helpless for asymmetric active current part, sometimes but make the degree of unbalance of electric current likely larger after reactive power compensation, therefore electric industry power supply department can only adopt the mode of artificial separated time to carry out load adjustment.
From the above, the three-phase load unbalance of using electricity system is very serious on the harm of transformer, electric equipment and using electricity system and impact, especially forms great obstacle to fully effectively utilizing of electric power energy.In today that supply of electric power is in short supply, the three-phase imbalance problem solving using electricity system has been extremely urgent task.
Summary of the invention
The present invention by the problem effectively solved, can not provide a kind of unbalanced load compensation arrangement and compensation method to solve electrical network three-phase load unbalance.
The present invention adopts following technical scheme to realize: a kind of unbalanced load compensation arrangement, comprise the three-phase four-arm full bridge inverter that brachium pontis is made up of the IGBT of two series connection, Hall voltage transducer, Hall current sensor, with the digital signal processor DSP of phase-locked loop program and PWM driver module in it, pi controller is comprised in digital signal processor DSP, the input of three-phase four-arm full bridge inverter is connected with three-phase and four-line electrical network by inductance, the output of three-phase four-arm full bridge inverter is connected with DC bus capacitor and is connected with the DC voltage input end of digital signal processor DSP, Hall voltage transducer is all connected with three-phase and four-line electrical network with the former limit of Hall current sensor, Hall voltage transducer is connected with the input of filter circuit with the secondary of Hall current sensor, the output of filter circuit is connected with the input of digital signal processor DSP, the output of digital signal processor DSP is connected with the output of PWM driver module, the output of PWM driver module is connected with the control end of IGBT.
Utilize the compensation method of above-mentioned compensation arrangement, comprise the following steps:
S1: the phase voltage of Hall voltage transducer and Hall current sensor real-time sampling three-phase and four-line electrical network, phase current and current in middle wire, and the phase voltage of sampling, phase current and current in middle wire are input to filter circuit carry out filtering process;
S2: in filtered phase voltage, phase current and current in middle wire supplied with digital signal processor DSP, the phase-locked loop program in digital signal processor DSP produces fixed phase according to phase voltage;
S3: filtered phase current is converted into electric current I d, Iq under d, q rotating coordinate system in digital signal processor DSP through 3/2 coordinate transform system and according to fixed phase, current in middle wire obtains electric current I n after over-sampling;
S4: digital signal processor DSP is by the direct voltage reference value preset and input actual DC magnitude of voltage by three-phase four-arm full bridge inverter and subtract each other and obtain direct voltage difference Δ U, and direct voltage difference Δ U obtains d shaft current target reference through pi controller;
S5: the electric current I d of gained and d axle target reference subtract each other and obtain d axle amount to be compensated, electric current I q and q axle target reference subtract each other and obtain q axle amount to be compensated, electric current I n and 0 axle target reference subtract each other and obtain 0 axle amount to be compensated, and q axle target reference and 0 axle target reference are all set to zero;
S6: amount to be compensated is sent in pi controller respectively, pi controller obtains dutyfactor value Dd, Dq and D0 of d axle, q axle and 0 axle;
S7: above-mentioned dutyfactor value Dd, Dq are sent into 2/3 converted coordinate system obtain three phase coordinate systems under respective duty ratio Da, Db, Dc sum D0 is delivered to each self-corresponding IGBT, control IGBT turns on and off;
S8: the DC voltage of three-phase four-arm full bridge inverter remains constant by duty ratio Da, Db, Dc and D0, three-phase four-arm full bridge inverter AC then exports offset current and compensates in three-phase and four-line electrical network, makes the load balancing of three-phase and four-line electrical network.
Traditional compensation method stresses the harmonic management of electrical network, and this device can export offset current to electrical network, make the load balancing of electrical network, and the adjustable degree of unbalance scope of device is comparatively large, utilize this device compensation method simple, without the need to calculating q axle and 0 axle target reference, therefore arithmetic speed is very fast, low to device hardware requirement, dynamic compensation is effective, can realize the continuous dynamic compensation under large unbalance loading condition.
Accompanying drawing explanation
Fig. 1 is the structural representation of compensation arrangement.
Fig. 2 is the flow chart of compensation method.
Current waveform figure when Fig. 3 is network load imbalance.
Fig. 4 is the power network current oscillogram after compensation arrangement compensates.
Fig. 5 is the control algolithm figure of compensation arrangement.
Embodiment
A kind of unbalanced load compensation arrangement, comprise the three-phase four-arm full bridge inverter that brachium pontis is made up of the IGBT of two series connection, Hall voltage transducer, Hall current sensor, with the digital signal processor DSP of phase-locked loop program and PWM driver module in it, pi controller is comprised in digital signal processor DSP, the input of three-phase four-arm full bridge inverter is connected with three-phase and four-line electrical network by inductance, the output of three-phase four-arm full bridge inverter is connected with DC bus capacitor and is connected with the DC voltage input end of digital signal processor DSP, Hall voltage transducer is all connected with three-phase and four-line electrical network with the former limit of Hall current sensor, Hall voltage transducer is connected with the input of filter circuit with the secondary of Hall current sensor, the output of filter circuit is connected with the input of digital signal processor DSP, the output of digital signal processor DSP is connected with the output of PWM driver module, the output of PWM driver module is connected with the control end of IGBT.
Utilize the compensation method of above-mentioned compensation arrangement, comprise the following steps:
S1: the phase voltage of Hall voltage transducer and Hall current sensor real-time sampling three-phase and four-line electrical network, phase current and current in middle wire, and the phase voltage of sampling, phase current and current in middle wire are input to filter circuit carry out filtering process;
S2: in filtered phase voltage, phase current and current in middle wire supplied with digital signal processor DSP, the phase-locked loop program in digital signal processor DSP produces fixed phase according to phase voltage;
S3: filtered phase current is converted into electric current I d, Iq under dq rotating coordinate system in digital signal processor DSP through 3/2 coordinate transform system and according to fixed phase, current in middle wire obtains electric current I n after over-sampling;
S4: digital signal processor DSP is by the direct voltage reference value preset and input actual DC magnitude of voltage by three-phase four-arm full bridge inverter and subtract each other and obtain direct voltage difference Δ U, and direct voltage difference Δ U obtains d shaft current target reference through pi controller;
S5: the electric current I d of gained and d axle target reference subtract each other and obtain d axle amount to be compensated, electric current I q and q axle target reference subtract each other and obtain q axle amount to be compensated, electric current I n and 0 axle target reference subtract each other and obtain 0 axle amount to be compensated, and q axle target reference and 0 axle target reference are all set to zero;
S6: amount to be compensated is sent in pi controller respectively, pi controller obtains dutyfactor value Dd, Dq and D0 of d axle, q axle and 0 axle;
S7: above-mentioned dutyfactor value Dd, Dq are sent into 2/3 converted coordinate system obtain three phase coordinate systems under respective duty ratio Da, Db, Dc sum D0 is delivered to each self-corresponding IGBT, control IGBT turns on and off;
S8: the DC voltage of three-phase four-arm full bridge inverter remains constant by duty ratio Da, Db, Dc and D0, three-phase four-arm full bridge inverter AC then exports offset current and compensates in three-phase and four-line electrical network, makes the load balancing of three-phase and four-line electrical network.
During concrete enforcement, be provided with communication module in digital signal processor DSP, surveillance that can be outside by this communication module carries out communication, observes the signal such as voltage, electric current by surveillance.
Claims (2)
1. a unbalanced load compensation arrangement, it is characterized in that comprising the three-phase four-arm full bridge inverter that brachium pontis is made up of the IGBT of two series connection, Hall voltage transducer, Hall current sensor, with the digital signal processor DSP of phase-locked loop program and PWM driver module in it, pi controller is comprised in digital signal processor DSP, the input of three-phase four-arm full bridge inverter is connected with three-phase and four-line electrical network by inductance, the output of three-phase four-arm full bridge inverter is connected with DC bus capacitor and is connected with the DC voltage input end of digital signal processor DSP, Hall voltage transducer is all connected with three-phase and four-line electrical network with the former limit of Hall current sensor, Hall voltage transducer is connected with the input of filter circuit with the secondary of Hall current sensor, the output of filter circuit is connected with the input of digital signal processor DSP, the output of digital signal processor DSP is connected with the output of PWM driver module, the output of PWM driver module is connected with the control end of IGBT.
2. utilize a compensation method for the compensation arrangement described in claim 1, it is characterized in that comprising the following steps:
S1: the phase voltage of Hall voltage transducer and Hall current sensor real-time sampling three-phase and four-line electrical network, phase current and current in middle wire, and the phase voltage of sampling, phase current and current in middle wire are input to filter circuit carry out filtering process;
S2: in filtered phase voltage, phase current and current in middle wire supplied with digital signal processor DSP, the phase-locked loop program in digital signal processor DSP produces fixed phase according to phase voltage;
S3: filtered phase current is converted into electric current I d, Iq under d, q rotating coordinate system in digital signal processor DSP through 3/2 coordinate transform system and according to fixed phase, current in middle wire obtains electric current I n after over-sampling;
S4: digital signal processor DSP is by the direct voltage reference value preset and input actual DC magnitude of voltage by three-phase four-arm full bridge inverter and subtract each other and obtain direct voltage difference Δ U, and direct voltage difference Δ U obtains d shaft current target reference through pi controller;
S5: the electric current I d of gained and d axle target reference subtract each other and obtain d axle amount to be compensated, electric current I q and q axle target reference subtract each other and obtain q axle amount to be compensated, electric current I n and 0 axle target reference subtract each other and obtain 0 axle amount to be compensated, and q axle target reference and 0 axle target reference are all set to zero;
S6: amount to be compensated is sent in pi controller respectively, pi controller obtains dutyfactor value Dd, Dq and D0 of d axle, q axle and 0 axle;
S7: above-mentioned dutyfactor value Dd, Dq are sent into 2/3 converted coordinate system obtain three phase coordinate systems under respective duty ratio Da, Db, Dc sum D0 is delivered to each self-corresponding IGBT, control IGBT turns on and off;
S8: the DC voltage of three-phase four-arm full bridge inverter remains constant by duty ratio Da, Db, Dc and D0, three-phase four-arm full bridge inverter AC then exports offset current and compensates in three-phase and four-line electrical network, makes the load balancing of three-phase and four-line electrical network.
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104682407A (en) * | 2015-03-23 | 2015-06-03 | 太原理工大学 | Load imbalance compensation system comprising amplitude-limiting controller and amplitude-limiting compensation method |
| CN104953606A (en) * | 2015-07-20 | 2015-09-30 | 兰州理工大学 | Networked layered compensation method for voltage unbalance of PCC (Point of Common Coupling) of islanded microgrid |
| CN106067722A (en) * | 2016-02-25 | 2016-11-02 | 中国科学院等离子体物理研究所 | A kind of signal synchronizing method |
| CN107947623A (en) * | 2017-11-24 | 2018-04-20 | 太原理工大学 | The multi-modal autonomous progress control method of two-way AC/DC converters under the conditions of a kind of laod unbalance |
| CN108886327A (en) * | 2016-03-30 | 2018-11-23 | 理想能量有限公司 | Micro-capacitance sensor power framework |
| CN109066712A (en) * | 2018-08-09 | 2018-12-21 | 海南金盘智能科技股份有限公司 | A kind of individual-phase control method and system of the parallel three level SVG of three-phase and four-line |
| US10840825B2 (en) | 2017-10-26 | 2020-11-17 | Industrial Technology Research Institute | Voltage balance control method and device for three-phase DC-AC inverter |
| CN113964831A (en) * | 2021-10-29 | 2022-01-21 | 国网北京市电力公司 | Load adjusting method and device, electronic equipment and computer readable storage medium |
| CN114243733A (en) * | 2021-12-08 | 2022-03-25 | 国网福建省电力有限公司晋江市供电公司 | Three-phase voltage unbalance treatment device and method based on voltage dynamic compensation |
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| CN103259277A (en) * | 2013-06-06 | 2013-08-21 | 国家电网公司 | Three-phase load unbalance compensator |
| CN203632572U (en) * | 2013-12-24 | 2014-06-04 | 珠海格力电器股份有限公司 | Converter and Photovoltaic Power Generation System |
| CN104009486A (en) * | 2014-06-20 | 2014-08-27 | 安徽工业大学 | Current limiting method for asymmetric compensation for SVG of three-phase three-wire system |
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| CN101499728A (en) * | 2008-10-29 | 2009-08-05 | 株洲变流技术国家工程研究中心有限公司 | High voltage frequency conversion apparatus having STATCOM function, control method and control apparatus |
| CN103259277A (en) * | 2013-06-06 | 2013-08-21 | 国家电网公司 | Three-phase load unbalance compensator |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104682407A (en) * | 2015-03-23 | 2015-06-03 | 太原理工大学 | Load imbalance compensation system comprising amplitude-limiting controller and amplitude-limiting compensation method |
| CN104953606A (en) * | 2015-07-20 | 2015-09-30 | 兰州理工大学 | Networked layered compensation method for voltage unbalance of PCC (Point of Common Coupling) of islanded microgrid |
| CN106067722A (en) * | 2016-02-25 | 2016-11-02 | 中国科学院等离子体物理研究所 | A kind of signal synchronizing method |
| CN108886327A (en) * | 2016-03-30 | 2018-11-23 | 理想能量有限公司 | Micro-capacitance sensor power framework |
| CN108886327B (en) * | 2016-03-30 | 2020-12-18 | 理想能量有限公司 | Micro-grid power architecture |
| US10840825B2 (en) | 2017-10-26 | 2020-11-17 | Industrial Technology Research Institute | Voltage balance control method and device for three-phase DC-AC inverter |
| CN107947623A (en) * | 2017-11-24 | 2018-04-20 | 太原理工大学 | The multi-modal autonomous progress control method of two-way AC/DC converters under the conditions of a kind of laod unbalance |
| CN109066712A (en) * | 2018-08-09 | 2018-12-21 | 海南金盘智能科技股份有限公司 | A kind of individual-phase control method and system of the parallel three level SVG of three-phase and four-line |
| CN109066712B (en) * | 2018-08-09 | 2021-12-31 | 海南金盘智能科技股份有限公司 | Phase splitting control method and system for three-phase four-wire parallel type three-level SVG |
| CN113964831A (en) * | 2021-10-29 | 2022-01-21 | 国网北京市电力公司 | Load adjusting method and device, electronic equipment and computer readable storage medium |
| CN113964831B (en) * | 2021-10-29 | 2023-11-24 | 国网北京市电力公司 | Load adjusting method, load adjusting device, electronic equipment and computer readable storage medium |
| CN114243733A (en) * | 2021-12-08 | 2022-03-25 | 国网福建省电力有限公司晋江市供电公司 | Three-phase voltage unbalance treatment device and method based on voltage dynamic compensation |
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