CN105762829A - Microgrid inverter grid disconnection/connection seamless switching control method based on phase angle estimation - Google Patents

Microgrid inverter grid disconnection/connection seamless switching control method based on phase angle estimation Download PDF

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CN105762829A
CN105762829A CN201410784176.0A CN201410784176A CN105762829A CN 105762829 A CN105762829 A CN 105762829A CN 201410784176 A CN201410784176 A CN 201410784176A CN 105762829 A CN105762829 A CN 105762829A
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phase angle
grid
voltage
value
inverter
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CN201410784176.0A
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CN105762829B (en
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卞晶
臧传治
曾鹏
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中国科学院沈阳自动化研究所
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00Climate change mitigation technologies for sector-wide applications
    • Y02P80/10Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
    • Y02P80/14District level solutions, i.e. local energy networks

Abstract

The invention relates to a microgrid inverter grid disconnection/connection seamless switching control method based on phase angle estimation. An energy storage system serves as a main power supply, and comprises an energy storage battery, a current transformer, and a PCS mode controller. In a grid connection mode, PQ control is employed; in an island mode, V/F control is employed. During the switching from the grid connection mode to the island mode, a voltage amplitude reference value is given by a phase voltage peak value of a power grid before grid disconnection, and is calculated through a mean value of angular frequency of the power grid before grid disconnection and an instant phase angle at the moment of grid disconnection. During the switching from the island mode to a grid connection mode, a phase angle reference value of the inverter in the V/F mode is modified through a phase angle estimation algorithm based on an instant voltage value of the power grid, the phase angle of the power grid is tracked quickly, and a precise voltage phase angle is employed for replacing an estimation value after the stable phase locking of PLL. Through the superposing of frequency interference quantities, the method judges whether the grid connection of a microgrid is completed or not. The method changes the corresponding control modes, and achieves the seamless switching.

Description

Based on the microgrid inverter of phase angle estimation from grid-connected seamless switching control method
Technical field
The present invention relates to micro-capacitance sensor and control technical field, especially the micro-capacitance sensor off-grid grid-connected seamless switching technique containing distributed power source, a kind of microgrid inverter based on phase angle estimation is from grid-connected seamless switching control method specifically.
Background technology
Development along with distributed power generation and modern power systems.Micro-capacitance sensor is suggested as a kind of novel distribution solution.It can not only improve power supply quality and reliability. and the energy and ambient pressure can be alleviated, and therefore win and increasingly paid attention to widely.Micro-grid system is made up of distributed new generating, energy storage and local load.Wherein energy storage device combines with renewable energy power generation technology. and the quality of power supply, the stability of system and resource utilization be can improve, the intermittence of generation of electricity by new energy output, undulatory property stabilized when micro-grid connection.
At present, microgrid operates mainly under grid-connected or two kinds of operational modes of isolated island, under normal circumstances, microgrid and public electric wire net parallel running, when public electric wire net breaks down or the quality of power supply is unsatisfactory for burden requirement, microgrid can quickly disconnect the connection of electrical network, is transitioned into island operation state, to ensure the continued power of important load in microgrid region.When microgrid runs different from the control mode of its internal converter time under different mode.How between both of which, to realize seamless switching so that the operational mode switching of microgrid is minimum to the disturbance of load and electrical network, is realize the maximized key control technology of distributed energy utilization rate.Seamless switching refers to micro-capacitance sensor voltage, Frequency Smooth transition in quick handoff procedure, it is possible in the scope that the standard of running on specifies, it is ensured that the sensitive load in micro-grid system is properly functioning.
Summary of the invention
In order to solve micro-capacitance sensor occur in running grid-connected/isolated island conversion time, to in system sensitive load provide continuously can be high power supply, the present invention proposes a kind of microgrid inverter based on phase angle estimation from grid-connected seamless switching control method, shorten switching time, avoid exporting the overcurrent phenomenon occurred when implementing grid-connected under phase angle and the incomplete synchronous situation of bulk power grid phase angle at inverter simultaneously.
The present invention for achieving the above object the technical scheme is that a kind of based on phase angle estimation microgrid inverter from grid-connected seamless switching control method, including:
It is at micro-capacitance sensor grid-connected in isolated island switch mode process, carries out the transformation to V/F control algolithm of the PQ control algolithm, the reference quantity of voltage magnitude and voltage phase angle in given V/F control algolithm;
It is in isolated island in grid-connected switch mode process, estimating phase angle reference value in inverter V/F pattern first with the phase angle algorithm for estimating based on line voltage instantaneous value, thus following the tracks of electrical network phase angle at micro-capacitance sensor;PLL stablize phase-locked after, then with PLL locking voltage phase angle value replace estimated value, complete the tracking of phase angle;After inversion output meets grid-connected conditions, Guan Bi PCC place chopper;By judging whether micro-capacitance sensor has been parallel on electrical network completely to the method for reference angle frequency superposition interference volume, if being closed, then conversion inverter controller pattern is to PQ control algolithm, completes isolated island to grid-connected switching, and otherwise microgrid still works in V/F pattern.
The electrical network phase voltage peak value that in described V/F control algolithm, the reference quantity of voltage magnitude is measured by the voltage sensor being arranged on before off-network on point of common coupling gives.
In described V/F control algolithm, the reference quantity of voltage phase angle is calculated by the angular frequency meansigma methods of electrical network before off-network and the instantaneous phase angle in off-network moment and obtains:
θref=∫ ωgdt+θ0(1)
Wherein, θrefFor the reference quantity of voltage phase angle, ωgFor the angular frequency meansigma methods of electrical network before off-network, t is the time, θ0Instantaneous phase angle for the off-network moment.
Described utilization estimates phase angle reference value in inverter V/F pattern based on the phase angle algorithm for estimating of line voltage instantaneous value, comprises the following steps:
If grid line voltmeter is shown as U ab = 2 u l - l cos ( θ g ) , U bc = 2 U l - l cos ( θ g - 2 3 π ) , Wherein, UabFor the voltage that AB is alternate, UbcFor the voltage that BC is alternate, Ul-lFor the virtual value of line voltage, θgFor;
Then estimation electrical network angle values is expressed as:
&theta; ~ g = arccos ( U ab 2 U l - l ) , 0 < &theta; ~ g < &pi; , Or &theta; ~ g = - arccos ( U ab 2 U l - l ) , - &pi; < &theta; ~ g < 0
By judging sgn (Uab+2Ubc) value, phase angle estimated value can be determinedScope, as sgn (Uab+2UbcDuring)=1,As sgn (Uab+2UbcDuring)=-1
Described grid-connected conditions is:
Phase angle difference between inverter and electrical networkIn allowed band, meanwhile, line current Il-l<△Ith
The present invention has the following advantages and beneficial effect:
1) in isolated island to also network process, use and estimate that the grid voltage phase-angle obtained is as inverter phase angle command value based on line voltage instantaneous value, shorten phase angle tracking velocity, avoid PLL be phase-locked to steady statue and cause long time wait, avoid grid-connected overcurrent that is different from grid phase angle due to inverter output and that cause, it is achieved the seamless switching of fast and stable simultaneously.
2) judge that whether PCC is of completely closed by software algorithm, it is to avoid due to PCC place chopper physical switch movement time and controller software Schema control switching time is asynchronous and the switching abnormal phenomena that causes.
3) only by using one group of voltage and current sensor measurement PCC point place line voltage, current value to judge PCC point place electric network state, do not use static switch, reduce cost, simplify the control to PCC point simultaneously.
Accompanying drawing explanation
Fig. 1 is that major loop of the present invention connects circuit diagram;
Fig. 2 is the microgrid schematic flow sheet by grid-connect mode startup work;
Fig. 3 is in the seamless switching procedure schematic diagram of island mode by grid-connect mode transition;
Fig. 4 is the seamless switching procedure schematic diagram being transitted to grid-connect mode by island mode;
In figure: 1 main electrical network, 2 voltage sensors, 3 current sensors, 4 grid-connected choppers, 5 loads, 6 energy-storage systems (are made up of energy-storage battery, current transformer, PCS controller), and 7 phase angle estimation links, 8PCC Guan Bi judges link, and 9 grid-connected completing judge link.
Detailed description of the invention
Below in conjunction with drawings and Examples, the present invention is described in further detail.
In FIG, chopper K1 is installed at grid-connected point of common coupling (PCC) place, is responsible for implementing the grid-connected and off-network operation of micro-capacitance sensor.Inverter controller need not obtain the state of K1.Net side at PCC and voltage sensor PT1, current sensor CT1 are installed, measure line voltage respectively and flow through the current value of PCC point.Seamless switching it is critical only that the handoff procedure to energy-storage system (main power source) mode of operation.
Use voltage sensor PT1 to measure the line voltage of three-phase power grid voltage, and input in controller in PLL phaselocked loop, phaselocked loop obtain electrical network angular frequency and real time phasor value, be stored in controller unit.
Use Mode labelling micro-capacitance sensor operational mode, when Mode value is+1 ,-1, when 0, represent micro-capacitance sensor respectively and run on grid-connect mode, island mode, isolated island extremely grid-connected standby mode.
Micro-capacitance sensor is in grid-connect mode.When PCC point breaker K1 closes, when micro-capacitance sensor is parallel on electrical network, inverter works in current source mode, uses PQ control method, and inverter exports constant active power and reactive power, voltage magnitude and frequency are maintained by bulk power grid.PQ control algolithm is all described later in detail in a lot of documents, no longer repeats in the present invention.
Micro-capacitance sensor is in island mode.When PCC point breaker K1 disconnects, micro-capacitance sensor and electrical network are not connected to and independent operating, and inverter works in voltage source mode, use V/F control method, the reference value of given inverter controller input voltage and phase angle, makes the voltage of inverter output continuous-stable, reduces the disturbance to sensitive load.
Micro-capacitance sensor is in grid-connected to isolated island switch mode.When grid voltage amplitude or electric voltage frequency exceed allowed band, bulk power grid can not provide high intelligent electric energy to load, and now micro-capacitance sensor needs the quick connection disconnected with bulk power grid according to electric energy relevant criterion, independently powers to load.Need to carry out the transformation of PQ to V/F control algolithm from grid-connected to inverter controller the handoff procedure of isolated island, at once give the reference quantity of voltage magnitude and initial phase angle in V/F control algolithm.The electrical network phase voltage peak value that wherein voltage magnitude is measured by PT1 before off-network gives, and voltage phase angle value is calculated by the angular frequency meansigma methods of electrical network before off-network and the instantaneous phase angle in off-network moment and obtains.
θref=∫ ωgdt+θ0(1)
Micro-capacitance sensor is in isolated island to grid-connected switch mode.After detecting that power system restoration is powered, utilize the phase angle algorithm for estimating based on line voltage instantaneous value to change phase angle reference value in inverter V/F pattern, quickly follow the tracks of electrical network phase angle, PLL stablize phase-locked after, replace estimated value by voltage phase angle value accurately again, complete the tracking of phase angle.After inversion output meets grid-connected conditions, Guan Bi PCC place chopper, and by judging whether microgrid has been parallel on electrical network completely to the method for reference angle frequency superposition interference volume, if being closed, then conversion inverter controller pattern is to PQ control algolithm, completing isolated island to grid-connected switching, otherwise microgrid still works in V/F pattern.
Workflow under grid-connect mode as shown in Figure 2.Judging that whether electrical network sampling line voltage magnitude, frequency are beyond allowed band, if not transfiniting, microgrid operates under grid-connect mode, it is labeled as Mode=+1, uses PQ control algolithm, according to information such as load and energy storage device capacity, given P and Q reference value, inversion exports constant active power and reactive power.Meanwhile, phaselocked loop latch line voltage angular frequency and real time phasor value are recorded in controller memory element.
As it is shown on figure 3, once voltage magnitude or frequency are beyond allowed band, illustrates that bulk power grid is not provided that burning voltage, microgrid needs to disconnect the connection with bulk power grid, enters island mode, is labeled as Mode=-1, changes control algolithm to V/F.Turned in isolated island process by grid-connected, line voltage angular frequency meansigma methods before the off-network of record in controller memory element and off-network moment angle values calculate and obtain phase angle reference value θ in V/F control algolithmref, by line voltage peak value before off-network as voltage magnitude reference value V in V/F control algolithmref, thus realizing grid-connected to off-grid seamless switching process.
When line voltage returns in allowed band, micro-capacitance sensor needs Guan Bi K1, island mode be transformed into grid-connect mode.Transformation process is as shown in Figure 4.To complete and net operation, inverter output voltage need to be met consistent with grid voltage amplitude, the phase angle theta of inverter output simultaneouslyrefWith electrical network phase angleIn certain allowed band, otherwise also net operation will cause instantaneous overcurrent phenomenon, and load causes obvious impact.When bulk power grid restores electricity, it is possible that very big error between inversion output phase angle and actual electric network phase angle, it is necessary to could be grid-connected after being tracked adjusting.DefinitionWhen its value is more than grid-connected permission setting value △ θthTime, in order to avoid the grid-connected transient over-current that causes in the widely different situation of phase angle, inverter controller enters Mode=0 phase angle tracking standby mode.Traditional control needs the electrical network angle values after by the phase-locked recovery of PLL phaselocked loop to adjust the phase angle reference value of inverter controller so that it is to follow the tracks of grid voltage phase-angle gradually, reduce both phase angle differences, it is achieved grid-connected.But this time needs to spend several cycle phaselocked loop could stably pin electrical network phase angle.In order to accelerate off-network to grid-connected transformation process, the present invention proposes the method using phase angle estimation, shortens the grid-connected delay caused due to PLL phase locked track phase angle, it is achieved off-network is to grid-connected seamless switching, and detailed process is:
(1) electrical network phase angle theta is estimated by grid line instantaneous voltageg, use symbolRepresent phase angle estimated value.In Fig. 4 shown in numbering 7 part.
If grid line voltage is represented by U ab = 2 u l - l cos ( &theta; g ) , U bc = 2 U l - l cos ( &theta; g - 2 3 &pi; ) ,
Then estimation electrical network angle values is expressed as
&theta; ~ g = arccos ( U ab 2 U l - l ) ( 0 < &theta; ~ g < &pi; ) Or &theta; ~ g = - arccos ( U ab 2 U l - l ) ( - &pi; < &theta; ~ g < 0 )
Pass throughPositive negative judgementResiding scope, because:
U ab + 2 U bc = 6 2 U l - l sin &theta; ~ g
So sgn (U only need to be judgedab+2Ubc) value, can determineScope.As sgn (Uab+2UbcDuring)=1,As sgn (Uab+2UbcDuring)=-1
By fixing sample frequency, it is possible to estimate a series of electrical network phase angleAccording to electrical network phase angle change rule it can be seen that these phase angle estimated values should show as the feature increased in 0-2 π scope internal linear, if sudden change occurs in estimated value, then it is assumed that be that abnormal data is inadvisable.The voltage phase angle value obtained by instantaneous value estimation as inversion phase angle command value, can make inverter quickly follow the tracks of grid voltage phase-angle.Simultaneously, line voltage is also carried out phase-locked calculating by PLL phaselocked loop, and when phaselocked loop is after several cycles can stably pin electrical network phase angle, estimation terminates, the phase-locked value of actual electric network phase angle replace
(2) phase angle difference between inverter and electrical network is comparedWhether meet allowed band, if in allowed band, close the grid-connected chopper in PCC place.In Fig. 4 shown in numbering 8 part.
(3) judging whether microgrid has been completely in and net state, conversion and control algorithm is to PQ control algolithm.In Fig. 4 shown in numbering 9 part.Usual chopper physical state is in Millisecond switching time, and the time of changing that inverter controller is performed control model by software is Microsecond grade, and not moment simultaneously completes in two class switchings.It is asynchronous it would appear that abnormal operating condition even results in handoff failure that the two switches.Controller judges that whether microgrid grid-connected successful method is: adds a High-frequency Interference amount △ ω in the voltage phase angle command value of inverter, determines whether grid-connected completing.Needing the addition ensureing this high-frequency interferencing signal that load is not impacted, its amplitude is taken as ± 0.15%f0, the frequency setting of superposition is 0.3Hz.If electrical network is in island mode, the superposition of High-frequency Interference will result in there is larger difference between PCC point voltage angular frequency reference quantity and electrical network actual angular frequency;If but electrical network is in grid-connect mode, the PCC point voltage angular frequency reference quantity of superposition interference volume is almost equal with line voltage angular frequency, because under grid-connect mode, voltage angle frequency is maintained by bulk power grid, not by the impact of micro-capacitance sensor.It can be considered that when the difference of angular frequencyLess than patten transformation limit value △ ωthTime, microgrid comes into and net state, and controller is transformed into PQ control algolithm, and otherwise still in off-network pattern, controller works in V/F pattern.

Claims (5)

1. one kind based on the microgrid inverter of phase angle estimation from grid-connected seamless switching control method, it is characterised in that including:
It is at micro-capacitance sensor grid-connected in isolated island switch mode process, carries out the transformation to V/F control algolithm of the PQ control algolithm, the reference quantity of voltage magnitude and voltage phase angle in given V/F control algolithm;
It is in isolated island in grid-connected switch mode process, estimating phase angle reference value in inverter V/F pattern first with the phase angle algorithm for estimating based on line voltage instantaneous value, thus following the tracks of electrical network phase angle at micro-capacitance sensor;PLL stablize phase-locked after, then with PLL locking voltage phase angle value replace estimated value, complete the tracking of phase angle;After inversion output meets grid-connected conditions, Guan Bi PCC place chopper;By judging whether micro-capacitance sensor has been parallel on electrical network completely to the method for reference angle frequency superposition interference volume, if being closed, then conversion inverter controller pattern is to PQ control algolithm, completes isolated island to grid-connected switching, and otherwise microgrid still works in V/F pattern.
2. the microgrid inverter based on phase angle estimation according to claim 1 is from grid-connected seamless switching control method, it is characterized in that, the electrical network phase voltage peak value that in described V/F control algolithm, the reference quantity of voltage magnitude is measured by the voltage sensor being arranged on before off-network on point of common coupling gives.
3. the microgrid inverter based on phase angle estimation according to claim 1 is from grid-connected seamless switching control method, it is characterized in that, in described V/F control algolithm, the reference quantity of voltage phase angle is calculated by the angular frequency meansigma methods of electrical network before off-network and the instantaneous phase angle in off-network moment and obtains:
θref=∫ ωgdt+θ0(1)
Wherein, θrefFor the reference quantity of voltage phase angle, ωgFor the angular frequency meansigma methods of electrical network before off-network, t is the time, θ0Instantaneous phase angle for the off-network moment.
4. the microgrid inverter based on phase angle estimation according to claim 1 is from grid-connected seamless switching control method, it is characterized in that, described utilization estimates phase angle reference value in inverter V/F pattern based on the phase angle algorithm for estimating of line voltage instantaneous value, comprises the following steps:
If grid line voltmeter is shown as U ab = 2 U l - l cos ( &theta; g ) , U bc = 2 U l - l cos ( &theta; g - 2 3 &pi; ) , Wherein, UabFor the voltage that AB is alternate, UbcFor the voltage that BC is alternate, Ul-lFor the virtual value of line voltage, θgFor;
Then estimation electrical network angle values is expressed as:
&theta; ~ g = arccos ( U ab 2 U l - l ) , 0 < &theta; ~ g < &pi; , Or &theta; ~ g = - arccos ( U ab 2 U l - l ) , - &pi; < &theta; ~ g < 0
By judging sgn (Uab+2Ubc) value, phase angle estimated value can be determinedScope, as sgn (Uab+2UbcDuring)=1,As sgn (Uab+2UbcDuring)=-1
5. the microgrid inverter based on phase angle estimation according to claim 1 is from grid-connected seamless switching control method, it is characterised in that described grid-connected conditions is:
Phase angle difference between inverter and electrical networkIn allowed band, meanwhile, line current Il-l<△Ith
CN201410784176.0A 2014-12-16 2014-12-16 Microgrid inverter based on phase angle estimation is from grid-connected seamless switching control method CN105762829B (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108599153A (en) * 2018-05-10 2018-09-28 国网江苏省电力有限公司徐州供电分公司 A kind of off-network for low pressure flexibility supplying power allocation system turns grid-connected Phase angle control method
CN110932315A (en) * 2019-11-22 2020-03-27 北京科诺伟业科技股份有限公司 Phase selection control method of quick switch

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110068631A1 (en) * 2008-06-10 2011-03-24 Rolls-Royce Plc Electrical generator network and a local electrical system
CN102545260A (en) * 2012-01-16 2012-07-04 中国电力科学研究院 Method for controlling automatic seamless switching between grid-connected mode and grid-isolated mode of microgrid
CN103560535A (en) * 2013-11-20 2014-02-05 北京四方继保自动化股份有限公司 Micro-grid operation mode seamless switching method based on energy storage current transformer
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

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110068631A1 (en) * 2008-06-10 2011-03-24 Rolls-Royce Plc Electrical generator network and a local electrical system
CN102545260A (en) * 2012-01-16 2012-07-04 中国电力科学研究院 Method for controlling automatic seamless switching between grid-connected mode and grid-isolated mode of microgrid
CN103560535A (en) * 2013-11-20 2014-02-05 北京四方继保自动化股份有限公司 Micro-grid operation mode seamless switching method based on energy storage current transformer
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

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
景雷: "微电网系统无缝切换策略研究与仿真", 《电气应用》 *
黄望军: "PWM整流器的双采样控制策略研究", 《湘潭大学自然科学学报》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108599153A (en) * 2018-05-10 2018-09-28 国网江苏省电力有限公司徐州供电分公司 A kind of off-network for low pressure flexibility supplying power allocation system turns grid-connected Phase angle control method
CN110932315A (en) * 2019-11-22 2020-03-27 北京科诺伟业科技股份有限公司 Phase selection control method of quick switch

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