CN103296696B - Inverter and control method thereof - Google Patents

Inverter and control method thereof Download PDF

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Publication number
CN103296696B
CN103296696B CN201310215236.2A CN201310215236A CN103296696B CN 103296696 B CN103296696 B CN 103296696B CN 201310215236 A CN201310215236 A CN 201310215236A CN 103296696 B CN103296696 B CN 103296696B
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China
Prior art keywords
inverter
grid
parameter
electrical network
control unit
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CN201310215236.2A
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Chinese (zh)
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CN103296696A (en
Inventor
朱建国
廖荣辉
曾炳光
沙旻
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深圳市永联科技股份有限公司
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Publication of CN103296696A publication Critical patent/CN103296696A/en
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Abstract

A kind of inverter, it comprises: inverter body, described inverter body comprises inverter power unit and inverter control unit, this inverter also comprises: be arranged on the distal contact device between described inverter body output and load or electrical network, be arranged on the inverter output voltage sampler of inverter body output, and be arranged on the line voltage sampler of electrical network end; Described inverter control unit sends from net or grid-connected instruction to inverter power unit, and described inverter control unit is also for controlling distal contact device that is closed or that disconnect between distributed generation system and electrical network.The beneficial effect of inverter of the present invention is: can realize independence or be incorporated into the power networks and taking over seamlessly between two kinds of operation modes, facilitating the mutual use of distribution type renewable energy and electrical network, unlikely impact electrical network, protection power grid security.

Description

Inverter and control method thereof
Technical field
The present invention relates to a kind of energy storage inverter and photovoltaic DC-to-AC converter, a kind of Dual-mode control method of inverter is provided, the independence of inverter can be realized or be incorporated into the power networks and taking over seamlessly between two kinds of operation modes, facilitate the mutual use of distribution type renewable energy and electrical network, for intelligent micro-grid development provides technical guarantee.
Background technology
Distributed power generation typically refers to and utilizes distributing resource, installation scale less, be arranged in electricity generation system near user, its generally access lower than the electrical network of 35 kilovolts or more low-voltage-grade.Distributed generation system comprises the electricity generation systems etc. such as distributed photovoltaic power generation, distributed energy storage, distributed wind energy, oil machine, has the concept of intelligent micro-grid.
Distributed photovoltaic power generation can meet the requirement namely sent out and namely use, reduce power transmission and transformation cost and power consumption, therefore, will become one of principal mode of China's development photovoltaic generation at Urban Scale Application in Building photovoltaic generating system.Along with city distributed photovoltaic system is progressively applied, building photovoltaic system presents the development trend of densification, multiple spot access urban power distribution network.
At present, be applied to the inverter of distributed photovoltaic power generation system and energy-storage system, only be confined to be incorporated into the power networks as the current source of routine or as conventional voltage source from net independent operating, just realize simple power to control, can not, from taking over seamlessly between grid-connected, particularly cannot realize taking over seamlessly from net to grid-connected.
Mainly realized by the rigid switching of inverter from net to grid-connected switching in prior art, that is, after inverter finds that power system restoration is powered, output phase place and the amplitude of uncomfortable inversion device make it consistent with the phase place of electrical network and amplitude, just direct closed distal contactor or static switch.Will inevitably cause the impact to electrical network or inverter like this, probably cause the Head switches trip protection of electrical network, or the accident such as the overcurrent of inverter is shut down, contactor or static switch damage occurs, and affects the safety of electrical network.
But as a part for intelligent grid, along with a large amount of access of distributed energy and the needs of electrical network intelligent construction, require that inverter possesses multi-operation mode, independence can be realized or be incorporated into the power networks and taking over seamlessly between two kinds of operation modes, facilitating the mutual use of distribution type renewable energy and electrical network.
In order to solve the problem, be necessary the control method of inventing a kind of inverter and this inverter in fact.
Summary of the invention
The object of the invention is, for overcoming above-mentioned the deficiencies in the prior art, to provide a kind of inverter, the independence of inverter can be realized or be incorporated into the power networks and taking over seamlessly between two kinds of operation modes, overcoming existing technological deficiency.
For achieving the above object, inverter of the present invention is design like this:
A kind of inverter, it comprises: inverter body, described inverter body comprises inverter power unit and inverter control unit, this inverter also comprises: be arranged on the distal contact device between described inverter body output and load or electrical network, be arranged on the inverter output voltage sampler (inverter output voltage sample circuit) of inverter body output, and be arranged on the line voltage sampler (line voltage sample circuit) of electrical network end; Described inverter control unit sends from net or grid-connected instruction to inverter power unit, and described inverter control unit is also for controlling distal contact device that is closed or that disconnect between distributed generation system and electrical network.
Preferably, described distal contact device is static switch, circuit breaker, contactor or other switching devices.
Another object of the present invention is to provide a kind of inverter control method by switching from net pattern to grid-connect mode, comprises the following steps:
Step 1, line voltage sampler obtain power system restoration power supply signal, described line voltage sampler by this signal feedback to inverter control unit;
Step 2, this inverter control unit are phase-locked to line voltage by phase-locked loop, and send instruction to inverter power unit, and the output parameter A of adjustment inverter power unit, makes it consistent with electrical network output parameter B;
Step 3, inverter control unit are by inverter output voltage sampler samples, and the parameter B that the parameter A export inverter power unit and electrical network export compares;
Step 4, parameter A or parameter A consistent with parameter B relative to the error of parameter B be less than set threshold values time, inverter control unit sends instruction, the distal contact device that closed load and distributed generation system are connected with electrical network, completes the switching from net pattern to grid-connect mode.
Preferably, the setting threshold in described step 4 is 10%.
Preferably, the parameter A in described step 2 at least comprises voltage-phase, amplitude.
Preferably, the parameter B in described step 2 at least comprises voltage-phase, amplitude.
Another object of the present invention be in order to provide a kind of by grid-connect mode to the inverter control method switched from net pattern, comprise the following steps:
Step 1, inverter control unit detect, and obtain electric network fault signal;
Step 2, inverter control unit send instruction, disconnect the distal contact device that distributed generation system is connected with electrical network;
The mode of operation of step 3, adjustment inverter is in voltage source mode, and output voltage parameter X fixes, and electric current is with local load variations;
Step 4, distributed generation system start power supply, complete grid-connect mode to the switching from net pattern.
Preferably, the parameter X in described step 3 is voltage magnitude and phase place.
The beneficial effect of inverter of the present invention is: can realize independence or be incorporated into the power networks and taking over seamlessly between two kinds of operation modes, facilitating the mutual use of distribution type renewable energy and electrical network, unlikely impact electrical network, protection power grid security.
Accompanying drawing explanation
Fig. 1 is the block diagram according to an embodiment of the invention.
Fig. 2 be inverter by grid-connect mode to the control flow chart switched from net pattern.
Fig. 3 is that inverter is by the control flow chart switched from net pattern to grid-connect mode.
Embodiment
Below in conjunction with drawings and Examples, the present invention is further described.
Refer to Fig. 1, inverter 1 of the present invention mainly comprises: inverter body 10, be arranged on the distal contact device 12 between described inverter body 10 output and electrical network, be arranged on the inverter output voltage sampler 14 of inverter body 10 output, and be arranged on the line voltage sampler 16 of electrical network end.
One end of inverter 1 of the present invention connects the energy-storage battery 30(such as solar battery array as local energy storage device), the other end connects local load 50, is convenient to inverter 1 of the present invention like this from network operation.Meanwhile, the one end connecting local load 50 is also connected with electrical network 40 by described distal contact device 12.
Described inverter body 10 comprises inverter power unit 100 and inverter control unit 102.Described inverter control unit 102 can send instruction to inverter power unit 100, closes or disconnects the distal contact device 12 between distributed generation system and bulk power grid, to realize from net or to be incorporated into the power networks.
Preferably, described distal contact device also can use static switch, circuit breaker, and contactor or other switching devices replace.
Inverter 1 of the present invention is divided into 4 kinds of logical schemas, is described below:
1) inverter works in from net pattern;
Inverter 1 powers on and allows distributed generation system to start, if distributed generation system is incorporated on electrical network, the described inverter control unit 102 of inverter 1 sends instruction, if the distal contact device 12(distributed generation system that first disconnecting consumers and distributed generation system are connected with bulk power grid is off-grid system, be not connected to the grid, can not above-mentioned steps be needed); Next, inverter control unit 102 sends instruction to inverter power unit 100, makes inverter work in voltage source mode.Now inverter output voltage is stablized, and electric current, with local load variations voltage current waveform, makes whole distributed generation system work in from net pattern.
2) inverter works in grid-connect mode
Inverter 1 powers on, energy-storage battery access distributed generation system, and described inverter control unit 102 sends instruction, the distal contact device 12 that closed local load is connected with bulk power grid; Inverter control unit 102 sends instruction to inverter power unit 100, makes inverter 1 work in grid-connected current source module.Now inverter output current according to MPPT maximum power point tracking algorithm (MPPT algorithm) to electrical network maximum capacity conveying electric current or carry out management of charging and discharging according to system requirements.
3) inverter works in grid-connect mode and switches to from net pattern
Inverter 1 works in the power-off of grid-connected current source module bulk power grid fault; Inverter control unit 102 carries out anti-islanding detection, and assert grid collapses, inverter 1 is in island mode; Inverter control unit 102 sends instruction, disconnects the distal contact device 12 that distributed generation system is connected with bulk power grid; The mode of operation of adjustment inverter 1 is in voltage source mode.Now the parameter X(of inverter output voltage is such as, amplitude and frequency) fixing, electric current, with local load variations, makes whole electricity generation system work in from net pattern.
4) inverter works in and switches to grid-connect mode from net pattern
Inverter 1 works in voltage source mode, and whole distributed generation system works in from net pattern, and bulk power grid restores electricity; Inverter 1 line voltage sampler 16 detects power network signal, feeds back to inverter control unit 102; Inverter control unit 102 is phase-locked to line voltage by phase-locked loop, instruction is sent to inverter power system 100, the output parameter A(of adjustment inverter 1 comprises voltage-phase, amplitude, frequency), make it consistent with the output parameter B of electrical network (comprising voltage-phase, amplitude, frequency); Inverter control system passes through inverter output voltage sampling circuit samples, the voltage-phase exported inverter, amplitude, frequency and electric network voltage phase, amplitude, frequency ratio are comparatively, when meeting grid-connected requirement (parameter A relative to parameter B consistent or error is less than the threshold values of setting time, such as be less than 10%), inverter control unit 102 sends instruction, the distal contact device that closed load and distributed generation system are connected with bulk power grid, realizes independent operating from net pattern taking over seamlessly to grid-connect mode.

Claims (7)

1. an inverter, it comprises: inverter body, and described inverter body comprises inverter power unit and inverter control unit, it is characterized in that:
This inverter also comprises: be arranged on the distal contact device between described inverter body output and load or electrical network, be arranged on the inverter output voltage sampler of inverter body output, and be arranged on the line voltage sampler of electrical network end;
Described inverter control unit sends from net or grid-connected instruction to inverter power unit, and described inverter control unit is also for controlling distal contact device that is closed or that disconnect between distributed generation system and electrical network;
Wherein, inverter comprises the following steps by switching from net pattern to grid-connect mode:
Step 1, line voltage sampler obtain power system restoration power supply signal, described line voltage sampler by this signal feedback to inverter control unit;
Step 2, this inverter control unit are phase-locked to line voltage by phase-locked loop, and send instruction to inverter power unit, the parameter A that adjustment inverter power unit exports, and make it consistent with the parameter B that electrical network exports;
Step 3, inverter control unit are by inverter output voltage sampler samples, and the parameter B that the parameter A export inverter power unit and electrical network export compares;
Step 4, parameter A or parameter A consistent with parameter B relative to the error of parameter B be less than set threshold values time, inverter control unit sends instruction, the distal contact device that closed load and distributed generation system are connected with electrical network, inverter is made to work in grid-connected current source module, now inverter output current is according to MPPT maximum power point tracking algorithm to electrical network maximum capacity conveying electric current or carry out management of charging and discharging according to system requirements, completes the switching from net pattern to grid-connect mode;
Inverter is comprised the following steps to switching from net pattern by grid-connect mode:
Step 1, inverter control unit detect, and obtain electric network fault signal;
Step 2, inverter control unit send instruction, disconnect the distal contact device that distributed generation system is connected with electrical network;
The mode of operation of step 3, adjustment inverter is in voltage source mode, and the parameter X of output voltage fixes, and electric current is with local load variations;
Step 4, distributed generation system start power supply, complete grid-connect mode to the switching from net pattern.
2. inverter as claimed in claim 1, is characterized in that: described distal contact device is static switch, circuit breaker, or contactor.
3. inverter as claimed in claim 1, wherein, inverter is 10% by the setting threshold in the step 4 switched from net pattern to grid-connect mode.
4. the inverter according to any one of claim 1-3, wherein, inverter at least comprises voltage-phase, amplitude by the parameter A in the step 2 switched from net pattern to grid-connect mode.
5. inverter as claimed in claim 4, wherein, inverter at least comprises voltage-phase, amplitude by the parameter B in the step 2 switched from net pattern to grid-connect mode.
6. the inverter according to any one of claim 1-3, wherein, inverter is voltage magnitude and phase place by grid-connect mode to the parameter X in the step 3 switched from net pattern.
7. inverter as claimed in claim 5, wherein, inverter is voltage magnitude and phase place by grid-connect mode to the parameter X in the step 3 switched from net pattern.
CN201310215236.2A 2013-06-03 2013-06-03 Inverter and control method thereof CN103296696B (en)

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CN104682445B (en) * 2013-11-29 2017-12-01 比亚迪股份有限公司 A kind of more transverters realize grid-connected method from off-network
CN103683324B (en) * 2013-12-04 2016-08-24 浙江大学 A kind of micro power network system is used for the droop control method of the improvement based on communication network of distributed power source parallel running mode
CN104078997A (en) * 2014-06-26 2014-10-01 许继电气股份有限公司 Photovoltaic grid-connected inverter grid-disconnecting mode and grid-connecting mode switching control method
EP3203598B1 (en) 2016-02-05 2020-10-07 Sungrow Power Supply Co., Ltd. Medium and high voltage grid-connected power generation system, medium and high voltage grid-connected system
CN105490308B (en) * 2016-02-05 2019-02-01 阳光电源股份有限公司 A kind of mesohigh grid-connected system and mesohigh grid-connected system
CN109217376B (en) * 2018-10-12 2020-07-07 西安许继电力电子技术有限公司 Synchronous switching-on control method of subway brake feedback converter
CN111049172A (en) * 2019-12-31 2020-04-21 科华恒盛股份有限公司 Method and system for switching from off-grid to grid-connected and energy storage converter

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CN102545257A (en) * 2012-01-12 2012-07-04 广东中商国通电子有限公司 Solar photovoltaic generating single-phase grid-connected inverter and control method thereof
CN102593832A (en) * 2012-03-15 2012-07-18 武汉大学 Three-wire DC microgrid system suitable for modern buildings and control method thereof.
CN203312829U (en) * 2013-06-03 2013-11-27 深圳市永联科技有限公司 Inverter capable of smoothly switching between grid-off mode and grid-connected mode

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CN102545257A (en) * 2012-01-12 2012-07-04 广东中商国通电子有限公司 Solar photovoltaic generating single-phase grid-connected inverter and control method thereof
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Inventor after: Zhu Jianguo

Inventor after: Liao Ronghui

Inventor after: Zeng Bingguang

Inventor after: Sha Min

Inventor before: Zhu Jianguo

Inventor before: Liao Ronghui

Inventor before: Zeng Bingguang

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Free format text: CORRECT: INVENTOR; FROM: ZHU JIANGUO LIAO RONGHUI CENG BINGGUANG TO: ZHU JIANGUO LIAO RONGHUI CENG BINGGUANG SHA MIN

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Address after: Shenzhen Nanshan District City, Guangdong province 518055 White Pine Road Baiwang letter two Industrial Park District building seventh

Applicant after: SHENZHEN WINLINE TECHNOLOGY CO., LTD.

Address before: Shenzhen Nanshan District City, Guangdong province 518000 White Pine Road Industrial Park two seventh district Baiwang letter building five floor

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