CN106602999B - A kind of Mixed cascading type photovoltaic inverter and control method based on super capacitor energy-storage - Google Patents
A kind of Mixed cascading type photovoltaic inverter and control method based on super capacitor energy-storage Download PDFInfo
- Publication number
- CN106602999B CN106602999B CN201611192934.5A CN201611192934A CN106602999B CN 106602999 B CN106602999 B CN 106602999B CN 201611192934 A CN201611192934 A CN 201611192934A CN 106602999 B CN106602999 B CN 106602999B
- Authority
- CN
- China
- Prior art keywords
- super capacitor
- photovoltaic
- voltage
- power
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000003990 capacitor Substances 0.000 title claims abstract description 90
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000004146 energy storage Methods 0.000 title claims abstract description 22
- 230000005611 electricity Effects 0.000 claims description 8
- 239000006185 dispersion Substances 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 2
- 238000001514 detection method Methods 0.000 claims description 2
- 230000005669 field effect Effects 0.000 claims description 2
- 238000005286 illumination Methods 0.000 claims description 2
- 229910044991 metal oxide Inorganic materials 0.000 claims description 2
- 150000004706 metal oxides Chemical class 0.000 claims description 2
- 239000004065 semiconductor Substances 0.000 claims description 2
- 230000006641 stabilisation Effects 0.000 claims description 2
- 238000011105 stabilization Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims 1
- 239000004576 sand Substances 0.000 claims 1
- 230000008901 benefit Effects 0.000 abstract description 6
- 238000010248 power generation Methods 0.000 abstract description 6
- 230000007812 deficiency Effects 0.000 abstract 1
- 230000000087 stabilizing effect Effects 0.000 abstract 1
- 239000004020 conductor Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 4
- 230000001939 inductive effect Effects 0.000 description 3
- 230000035800 maturation Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000011217 control strategy Methods 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 230000018199 S phase Effects 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
- H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
- H02S40/30—Electrical components
- H02S40/32—Electrical components comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
-
- H02J3/383—
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/345—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The present invention relates to a kind of Mixed cascading type photovoltaic inverter and control method based on super capacitor energy-storage.It include: super capacitor, photovoltaic cell, common filter capacitor, H bridge；The common filter capacitor of super capacitor, multiple photovoltaic cells and its parallel connection is connect with the DC side of H bridge respectively, then each H bridge carries out series connection in exchange side and forms higher voltage output, for absorbing the power of photovoltaic cell in photovoltaic cell capable of generating power peak period and in the deficiency of photovoltaic cell capable of generating power trough period compensation output power, to reduce the power swing of photovoltaic power generation.Super capacitor has certain memory capacity, and the advantage for having charge/discharge speed fast, thus has inborn advantage in terms of stabilizing power swing and overcoming grid voltage sags.
Description
Technical field
Research achievement of the invention is suitable for distributed photovoltaic power generation system, also may extend to the photovoltaic hair of large centralised
Electric system, in particular to a kind of Mixed cascading type photovoltaic inverter and control method based on super capacitor energy-storage.
Background technique
Distributed photovoltaic power generation system with energy storage link, conventional structure are that photovoltaic cell is passed through DC-DC
(DC/DC) converter and energy-storage travelling wave tube parallel connection, or both on DC bus passes through DC communication (DC/AC) inverter respectively
It is in parallel in exchange side.A kind of existing band stored energy distribution formula photovoltaic power generation system structure is as shown in Fig. 2.
This existing structure is that multiple photovoltaic cells are directly together in series, then by unified DC transfer circuit into
The whole maximum power control of row then directly and is connected in the DC side of inverter and carries out unified inversion output with super capacitor.
This existing structure is for New Cascading type structure proposed by the present invention, and overall structure is more simple, control strategy
Relatively easily, but there is also considerable problem, specifically there are these points:
(1) series connection of several photovoltaic cells is got up, although this mode is simple, is detrimental to mentioning for whole generating efficiency
It is high.Since when sunshine is uneven or battery behavior is uneven or has local shades or broken gravel etc. to cover photovoltaic battery panel, photovoltaic electric
The overall output power of pond group will reduce, and be unable to reach the maximum power of single battery plate.Also, if any in series connection
One cell malfunctions, then entire battery pack will fail.
(2) since photovoltaic system by single grid-connected inverters or powers to the load, DC side voltage of converter ratio
Higher, the voltage stress of corresponding each power device is also high.
(3) for super capacitor, monomer voltage is relatively low, usually only several volts, so being applied to photovoltaic system
It needs to connect.More series of connecting just are needed when DC bus-bar voltage is relatively high, which reduces equivalent capacity amounts, or
Need additional DC-DC (DC/DC) translation circuit.
(4) the output level number of single two level or three-level inverter is few, and harmonic content is high, needs relatively large volume
Output filter.
On the whole, the problems of this existing band energy storage photovoltaic power generation system structure, can be attributed to light
The problem that lying prostrate the mismatch between battery and the low-voltage and high line voltage of energy-storage travelling wave tube.If photovoltaic generating system
Independent load or power grid power supply to low-voltage, this contradiction are easy for alleviating, this will change multiple photovoltaic cells
The structure exported after plate series connection through single inverter.
Summary of the invention
Consider that the present invention proposes one kind from improve photovoltaic efficiency, reduce electricity generation system volume, reduce cost etc.
Photovoltaic cell and super capacitor are constituted photovoltaic using the cascade mode of H bridge by the photovoltaic DC-to-AC converter structure of new Mixed cascading type
Electricity generation system.This structure single-phase can use, and also may be constructed three-phase structure.Low-voltage device cost used in this structure
It is cheap and small in size, using maturation, and the volume of output filter can be substantially reduced, increase the hair of single photovoltaic cell
Electrical efficiency, high reliablity.
In order to achieve the above objectives, the present invention adopts the following technical scheme:
A kind of Mixed cascading type photovoltaic inverter based on super capacitor energy-storage, which is characterized in that super including one
Capacitor CsWith several dc-link capacitances, respectively dc-link capacitance C1, dc-link capacitance C2... dc-link capacitance
Cn；And inverter bridge H0, inverter bridge H1... inverter bridge Hn；The inverter bridge H1To HnRespectively with corresponding dc-link capacitance
C1, dc-link capacitance C2... dc-link capacitance CnIt is connected directly；It is sequentially connected in series between n+1 inverter bridge, further includes one
Super capacitor CsWith inverter bridge H0It is connected directly, it is described；N+1 inverter bridge is straight with 1 super capacitor and n again after being sequentially connected in series
Stream bus capacitor is connected directly the photovoltaic DC-to-AC converter of the H bridge cascade system constituted afterwards with the photovoltaic cell of dispersion.
In a kind of above-mentioned Mixed cascading type photovoltaic inverter based on super capacitor energy-storage, the switching tube of H bridge is constituted
There are many selections, using Metal-Oxide Semiconductor field effect transistor (MOSFET) or edge grid bipolar junction transistor
(IGBT)。
A kind of Mixed cascading type photovoltaic DC-to-AC converter control method based on super capacitor energy-storage, it is characterised in that:
Step 1, photovoltaic cell controls: determining direct current using maximal power tracing (MPPT) control method conductance increment method
Bus capacitor C1To CnVoltage-target, by inverter bridge H1To HnControl so that dc-link capacitance C1To CnVoltage
Reach target value, so that photovoltaic cell is kept maximum power output, wherein conductance increment method principle is instantaneous in relatively photovoltaic cell
The location of photovoltaic cell present operating point is differentiated on the basis of the variable quantity of the conductance and conductance of voltage and output power,
The control of maximum power is realized so as to adjust quiescent potential.
Step 2, super capacitor CsControl: due to the fluctuation of intensity of illumination, super capacitor should be in photovoltaic cell output work
Rate increases active output when being lower than rated output power, and absorbing when the output power from photovoltaic cells is higher than rated output power has
Function reduces inverter active output, to reduce the fluctuation of photovoltaic DC-to-AC converter output power；Super capacitor simultaneously can be according to need
Reactive power is adjusted, on the one hand reactive power consumed by the inductance being connected with power grid can be provided, on the other hand can also inhaled
It receives the reactive power issued from power grid or provides reactive power to power grid.
Wherein, with super capacitor CsConnected H0Phase, the amplitude of the output voltage of bridge, and be connected with photovoltaic cell inverse
Become bridge H1To HnOutput voltage phase, amplitude it is different, super capacitor C is controlled by the difference of both controlsCharging
With the switching of discharge condition, to keep super capacitor CsVoltage stabilization.
In a kind of above-mentioned Mixed cascading type photovoltaic inversion control method based on super capacitor energy-storage, all and photovoltaic electric
The connected inverter bridge H in pond1To HnOutput voltage phase it is identical, and the amplitude of output voltage is with the voltage of dc-link capacitance
Variation, amplitude are variable.
In a kind of above-mentioned Mixed cascading type photovoltaic inversion control method based on super capacitor energy-storage, with photovoltaic cell phase
Inverter bridge H even1To HnThe amplitude of output voltage, the determination method of phase be:
Step 1, the amplitude Vs and phase for detecting network voltage, make H1To HnOutput voltage phase and network voltage phase
Position is identical, and H1To HnOutput voltage amplitude summation Vp2 it is identical as the amplitude Vs of network voltage, i.e.,
Vp2=Vs (1)
Step 2, dc-link capacitance C that k-th of photovoltaic cell is directly connected is determined according to conductance increment methodkElectricity
Press target value Vdck, k=1,2 ... ... n.The ratio of the sum of Vdck and n dc-link capacitance voltage is amplitude distribution coefficient
Mk, i.e.,
Step 3, H1To HnThe amplitude of output voltage be respectively defined as U1 to Un, then the width of the output voltage of k-th of H bridge
Value Uk is determined by following formula:
Uk=Vp2×Mk (3)
6. a kind of Mixed cascading type photovoltaic inversion method based on super capacitor energy-storage according to claim 3,
It is characterized in that, described and super capacitor CsConnected inverter bridge H0The phase of output voltage, the specific determining method of amplitude be:
Step 1, using the phase of phaselocked loop detection network voltage, make H0Output voltage phase be ahead of network voltage
90 degree of phase；If super capacitor CsDC voltage be lower than rated value, then H0Output voltage phase be ahead of network voltage
Phase is (90+ α) degree；If super capacitor CsDC voltage be higher than rated value, then H0Output voltage phase be ahead of power grid
The phase of voltage is (90- α) degree；α is angle value greater than zero and adjustable.
Step 2, average anode current value Idck, k=1,2 ... ... the n of each photovoltaic cell are measured.N is calculated according to the following formula
A the output power from photovoltaic cells summation is
Then H0The amplitude Vp1 of output voltage determined by following formula, wherein filter inductance of the L between inverter and power grid
Inductance, f are the frequency of power grid:
Therefore, the present invention has the advantage that super capacitor is exchanging the cascade knot in side with the H bridge of photovoltaic cell through H bridge
Structure for comparing the cascade photovoltaic DC-to-AC converter of photovoltaic cell H bridge, further increases the quantity of the exchange cascade H bridge in side, thus
The level quantity for increasing synthesising output voltage, it is humorous that photovoltaic DC-to-AC converter more cascade than photovoltaic cell H bridge further reduced output
Wave.Common filter capacitor is in parallel with photovoltaic cell progress, is connected while playing a filtering role with H bridge.The present invention is cascaded using H bridge
Type grid-connected inverters, advantage are can to save output transformer, directly the output of synthesis high voltage, and this structure is used
Low-voltage device it is low in cost and small in size, using maturation, output filter volume can be substantially reduced in addition, increased single
The generating efficiency of photovoltaic cell improves reliability, therefore application prospect is fine.
Detailed description of the invention
Fig. 1 is system phase structure figure of the invention.
Fig. 2 photovoltaic cell and super capacitor are in DC bus system structure diagram in parallel.
Fig. 3 is the one phase equivalent circuit figure of mixed cell cascade structure.
Fig. 4 is the phasor diagram of photovoltaic generating system active power of output.
Fig. 5 is the phasor diagram of photovoltaic generating system active power of output, absorbing reactive power.
Fig. 6 is the phasor diagram of photovoltaic generating system active power of output, output reactive power.
Specific embodiment
Feasibility of the invention is described below in detail, the example is shown in the accompanying drawings, wherein identical from beginning to end or class
As label indicate same or similar element or element with the same or similar functions.Here is described by reference to attached drawing
Illustratively, for explaining only the invention, it is not considered as limiting the invention.
In figure: 1-Cs- super capacitor, 2-PV- photovoltaic cell, 3- conventional capacitive, 4-H bridge, 5-L- inductance, the super electricity of Vp1-
Hold unit output voltage, Vp2- photovoltaic cell output voltage, Isp- flows through inductive current, Vs- power grid phase voltage, on Vsl- inductance
Voltage, Zl- equivalent load, the sum of Vp- supercapacitive cell output voltage and photovoltaic cell output voltage.
One, circuit topology of the invention and basic control principle are introduced first.
A kind of Mixed cascading inverter structure with super capacitor energy-storage, including the super of photovoltaic cell (2) series connection with it
Capacitor (1), there are also the H bridges (4) being connected directly with every unit photovoltaic cell (2) and super capacitor (1), it is characterised in that: will surpass
Grade capacitor (1) and the photovoltaic cell (2) of dispersion use the cascade mode of H bridge to constitute photovoltaic DC-to-AC converter.
(1) photovoltaic cell is controlled, using classical maximal power tracing (MPPT) control method, such as conductance increment
Method, make photovoltaic cell keep maximum power output, wherein conductance increment method principle be relatively photovoltaic cell instantaneous voltage with it is defeated
The location of photovoltaic cell present operating point is differentiated on the basis of the conductance of power and the variable quantity of conductance out, so as to adjust
Quiescent potential realizes the control of maximum power.Preferably, there is higher precision compared to other method conductance increment methods
It is easy to operate simultaneously.Preferably, this structure realizes that every unit photovoltaic cell can accomplish that independent control, raising system are integrally sent out
Electrical efficiency.
(2) for super capacitor, energy density is small, power density is big, efficiency for charge-discharge is high, speed is fast and uses the longevity
Life length.Preferably, the control for super capacitor and coupled H bridge, by photovoltaic cell (group) and coupled
The output voltage of H bridge, the output voltage of super capacitor and coupled H bridge, this three's phase relation of network voltage and
The control of amplitude size is, it can be achieved that make up the quick drop of the output power from photovoltaic cells by super capacitor fast charging and discharging
Or the extra part of the output power from photovoltaic cells is absorbed, reduce the amplitude of photovoltaic cell capable of generating power power swing.Preferably, this
In structure while controlling super capacitor charging, electric discharge, it can be connected by the coupled H bridge of control and with photovoltaic cell
The phase difference of the output voltage of H bridge realizes absorption or compensates the purpose of power system reactive power, and photovoltaic cell and its connected H
Bridge is active power of output.
The cascade structure in side is being exchanged after being connected respectively with H bridge for photovoltaic cell with super capacitor, due to being illuminated by the light,
Unmatched influence between temperature and photovoltaic cell, the output characteristics of battery at different levels in cascade multilevel photovoltaic grid-connected inverter
Difference, peak power output are also different.When photovoltaic cell operates in respective maximum power according to the requirement that MPPT is controlled
When at point, DC bus-bar voltages at different levels can be unbalanced due to photovoltaic generation power and variation occurs, and be no longer consistent.
Since the present invention will guarantee the maximum power outputs of photovoltaic cells at different levels, for photovoltaic cell and super capacitor respectively with H
The cascade structure of bridge, control strategy of the invention should be in the controls of Traditional DC busbar voltage summation, power network current double-closed-loop control
Basis on, the requirement that the MPPT according to each photovoltaic cell is controlled determines the d-c bus voltage value of each H bridge, rather than as
Some cascade connection type photovoltaic DC-to-AC converters force the DC bus-bar voltage of each H bridge to be consistent as far as possible like that.
The cascade structure in side is being exchanged after being connected respectively with H bridge for photovoltaic cell with super capacitor, due to photovoltaic electric
Also there is a DC parallel capacitor between pond and H bridge, thus each H bridge can output reactive power and active power.It is controlled
Mode processed is flexible, is adapted to different demands.For example, the H bridge active power of output of (1) photovoltaic cell, the H bridge of super capacitor
Reactive power required for the inductance connecting with power grid is exported, super capacitor neither charges nor discharges at this time, entire inverter
Active power is only conveyed to power grid；(2) the H bridge active power of output of photovoltaic cell, the H bridge active power of output of super capacitor and
Reactive power, super capacitor discharges at this time, and entire inverter conveys active power and reactive power to power grid；(3) photovoltaic cell
H bridge active power of output, H bridge active power of output, the absorbing reactive power of super capacitor, at this time super capacitor discharge, it is whole
A inverter conveys active power, absorbing reactive power to power grid；(4) the H bridge of photovoltaic cell, the H bridge of super capacitor all export
Active power and reactive power in varying numbers, at this time super capacitor discharge, entire inverter to power grid conveying active power and
Reactive power；(5) the H bridge active power of output and reactive power of photovoltaic cell, the H bridge of super capacitor absorb active power, defeated
Reactive power out, super capacitor charges at this time, and entire inverter conveys active power and reactive power to power grid.
Two, specific control case is illustrated with reference to the accompanying drawing.
Shown in Fig. 1, the Mixed cascading type photovoltaic inverter of super capacitor energy-storage of the present invention, comprising: photovoltaic cell (2),
Filter capacitor (3), super capacitor (1), H bridge (4) and inductance (5).
Shown in Fig. 2, this is a kind of photovoltaic power generation system structure proposed.
It is the one phase equivalent circuit figure of mixed cell cascade structure, super capacitor output voltage V shown in Fig. 3p1And photovoltaic electric
Pond output voltage Vp2It is connected after series connection with power grid or load, VslIt is the voltage drop on inductance L, the electric current I of inductance Lsp, vector
Analysis is as shown in Figure 4.
Fig. 4 is that the Mixed cascading type photovoltaic inverter of super capacitor energy-storage of the present invention only issues the vector of active power
Figure.Due to super capacitor output voltage Vp1With photovoltaic cell output voltage Vp2The sum of VpIt is ahead of network voltage Vs, active power
Power grid is flowed to from inverter.Assuming that photovoltaic cells only export active, the output voltage V of photovoltaic cellsp2The direction (Fig. 4 middle conductor AO)
With network voltage VsSame-phase, amplitude size and VsIt is identical.Supercapacitive cell output voltage Vpl(Fig. 4 middle conductor DA) phase is super
It is preceding in network voltage Vs90 degree, voltage V on amplitude and inductance LslSize is identical.The electric current I of inductance L at this timespDirection and power grid electricity
Press VsDiffer 180 degree.It is found that the reactive power of supercapacitive cell outputting inductance L consumption at this time.If photovoltaic cells output electricity
Pressure amplitude value declines (such as Fig. 4 middle conductor CO), then supercapacitive cell output voltage Vp1It is ahead of network voltage VsPhase angle be less than
90 degree (such as Fig. 4 middle conductor DC), and its amplitude increases, super capacitor discharges at this time；If otherwise photovoltaic cells output voltage amplitude
It increases (such as Fig. 4 middle conductor BO), then supercapacitive cell output voltage Vp1It is ahead of network voltage VsPhase angle be greater than 90 degree and
Less than 180 degree (such as Fig. 4 middle conductor DB), and its amplitude increases, and super capacitor charges at this time.Meanwhile by controlling VpWith VsBetween
Phase relation and amplitude, so that it may while controlling active power and reactive power that photovoltaic generating system is conveyed to power grid.
Fig. 5 is the polar plot of absorbing reactive power while photovoltaic system issues active.Due to VpIt is ahead of network voltage
Vs, active power flow to power grid from inverter.VpAmplitude is less than network voltage VsAmplitude, inductive current I at this timespDirection it is stagnant
Afterwards in network voltage VsAngle be greater than 90 degree and less than 180 degree.Assuming that photovoltaic cells only export active, the output of photovoltaic cells
Voltage Vp2(such as line segment OA of Fig. 5) and IspAngle be 180 degree, then supercapacitive cell output voltage Vp1Lag behind Vp290 degree
(such as line segment AD of Fig. 5).Supercapacitive cell is at this time from power grid absorbing reactive power.If photovoltaic cells output voltage amplitude declines
(such as line segment OC of Fig. 5), then supercapacitive cell output voltage Vp1Lag behind Vp2Less than 90 degree (line segments of such as Fig. 5 of angle
CD), super capacitor discharges at this time；If otherwise photovoltaic cells output voltage amplitude increases (such as line segment OB of Fig. 5), super capacitor
Unit output voltage Vp1Lag behind Vp2Angle be greater than 90 degree and less than 180 degree (such as line segment BD of Fig. 5), super capacitor at this time
Charging.
Fig. 6 is the polar plot that reactive power is issued while photovoltaic system issues active power.Inverter output voltage Vp
It is ahead of network voltage Vs, and VpAmplitude is higher than network voltage Vs, inductive current I at this timespDirection be ahead of network voltage Vs's
Angle is greater than 90 degree and less than 180 degree, and active power and reactive power flow to power grid from inverter.Assuming that photovoltaic cells both export
Active power, and issue reactive power, the output voltage V of photovoltaic cellsp2It is ahead of network voltage VsAngle less than 90 degree, together
When lag behind Vp(such as Fig. 6 middle conductor OA), then supercapacitive cell output voltage Vp1It is ahead of network voltage VsAngle be less than
180 degree and it is ahead of Isp90 degree of phase angle (such as Fig. 6 middle conductor AD).Supercapacitive cell output reactive power at this time.If photovoltaic
Unit output voltage amplitude declines (such as Fig. 6 middle conductor OC), then supercapacitive cell output voltage Vp1It is ahead of network voltage Vs
Angle reduce (such as Fig. 6 middle conductor CD), amplitude increase, at this time super capacitor discharge；If otherwise photovoltaic cells output voltage width
Value increases (such as Fig. 6 middle conductor OB), then supercapacitive cell output voltage Vp1It is ahead of network voltage VsAngle increase (as scheme
6 middle conductor BD), super capacitor charges at this time.
By the above phasor analysis it is found that this Mixed cascading system is can be completed at the same time generation current control and it is super
The charge and discharge control of capacitor.
There is some researched and proposed to use H bridge cascaded inverter simultaneously in the photovoltaic plant of large centralised ground
Net, advantage are can to save output transformer, and directly synthesis high voltage output is grid-connected.In distributed photovoltaic system, due to
Existing power device can achieve line voltage grade, thus seem more simple direct using single inverter, using grade
Connection formula structure seems that structure is complicated, component is more.But for the present invention, low-voltage device used in this structure its at
This is very cheap and small in size, using maturation, can be substantially reduced the volume of output filter in addition, increase single photovoltaic cell
Generating efficiency, improve reliability, therefore structure and its control method of the invention have obvious advantage, be worthy to be popularized.
Specific embodiment described herein is only an example for the spirit of the invention.The neck of technology belonging to the present invention
The technical staff in domain can make various modifications or additions to the described embodiments or replace by a similar method
In generation, however, it does not deviate from the spirit of the invention or beyond the scope of the appended claims.
Claims (4)
1. a kind of Mixed cascading type photovoltaic DC-to-AC converter control method based on super capacitor energy-storage, mixed based on super capacitor energy-storage
Close cascade connection type photovoltaic inverter, including a super capacitor CsWith several dc-link capacitances, respectively DC bus electricity
Hold C1, dc-link capacitance C2... dc-link capacitance Cn；And inverter bridge H0, inverter bridge H1... inverter bridge Hn；It is described inverse
Become bridge H1To HnRespectively with corresponding dc-link capacitance C1, dc-link capacitance C2... dc-link capacitance CnIt is connected directly；n
It is sequentially connected in series between+1 inverter bridge, further includes a super capacitor CsWith inverter bridge H0It is connected directly, it is described；N+1 inverter bridge
It is connected directly the H bridge constituted afterwards with the photovoltaic cell of dispersion after being sequentially connected in series with 1 super capacitor and n dc-link capacitance again
The photovoltaic DC-to-AC converter of cascade system；There are many selections for the switching tube of composition H bridge, brilliant using Metal-Oxide Semiconductor field-effect
Body pipe or edge grid bipolar junction transistor.It is characterized by:
Step 1, photovoltaic cell controls: dc-link capacitance C is determined using maximum power tracking and controlling method conductance increment method1
To CnVoltage-target, by inverter bridge H1To HnControl so that dc-link capacitance C1To CnVoltage reach target
Value, make photovoltaic cell keep maximum power output, wherein conductance increment method principle be relatively photovoltaic cell instantaneous voltage with it is defeated
The location of photovoltaic cell present operating point is differentiated on the basis of the conductance of power and the variable quantity of conductance out, so as to adjust
Quiescent potential realizes the control of maximum power；
Step 2, super capacitor CsControl: due to the fluctuation of intensity of illumination, super capacitor should be lower than in the output power from photovoltaic cells
Increase active output when rated output power, active, reduction is absorbed when the output power from photovoltaic cells is higher than rated output power
Inverter active output, to reduce the fluctuation of photovoltaic DC-to-AC converter output power；Super capacitor can be adjusted as needed simultaneously
On the one hand reactive power can provide reactive power consumed by the inductance being connected with power grid, on the other hand can also absorb from electricity
It nets the reactive power issued or provides reactive power to power grid；
Wherein, with super capacitor CsConnected H0Phase, the amplitude of the output voltage of bridge, and the inverter bridge being connected with photovoltaic cell
H1To HnOutput voltage phase, amplitude it is different, super capacitor C is controlled by the difference of both controlsCharging and put
The switching of electricity condition, to keep super capacitor CsVoltage stabilization.
2. a kind of Mixed cascading type photovoltaic DC-to-AC converter control method based on super capacitor energy-storage according to claim 1,
It is characterized in that, all inverter bridge H being connected with photovoltaic cell1To HnOutput voltage phase it is identical, and the width of output voltage
It is worth the voltage change with dc-link capacitance, amplitude is variable.
3. a kind of Mixed cascading type photovoltaic DC-to-AC converter control method based on super capacitor energy-storage according to claim 1,
It is characterized in that, the inverter bridge H being connected with photovoltaic cell1To HnThe amplitude of output voltage, the determination method of phase be:
Step 1, the amplitude V of network voltage is detectedsAnd phase, make H1To HnOutput voltage phase and electric network voltage phase phase
Together, H1To HnOutput voltage amplitude summation Vp2With the amplitude V of network voltagesIt is identical, i.e.,
Vp2=Vs (1)
Step 2, dc-link capacitance C that k-th of photovoltaic cell is directly connected is determined according to conductance increment methodkVoltage mesh
Scale value Vdck, k=1,2 ... ... n；VdckRatio with the sum of n dc-link capacitance voltage is amplitude distribution coefficient Mk, i.e.,
Step 3, H1To HnThe amplitude of output voltage be respectively defined as U1To Un, then the amplitude U of the output voltage of k-th of H bridgekBy
Following formula determines:
Uk=Vp2×Mk (3)。
4. a kind of Mixed cascading type photovoltaic DC-to-AC converter control method based on super capacitor energy-storage according to claim 3,
It is characterized in that, described and super capacitor CsConnected inverter bridge H0Output voltage phase, the specific determining method of amplitude
It is:
Step 1, using the phase of phaselocked loop detection network voltage, make H0Output voltage phase be ahead of the phase of network voltage
90 degree；If super capacitor CsDC voltage be lower than rated value, then H0Output voltage phase be ahead of the phase of network voltage
For (90+ α) degree；If super capacitor CsDC voltage be higher than rated value, then H0Output voltage phase be ahead of network voltage
Phase be (90- α) degree；α is angle value greater than zero and adjustable；
Step 2, the average anode current value I of each photovoltaic cell is measureddck, k=1,2 ... ... n；N light is calculated according to the following formula
Lying prostrate cell output summation is
Then H0Output voltage amplitude Vp1It is determined by following formula, wherein the inductance of filter inductance of the L between inverter and power grid
Amount, f are the frequency of power grid:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611192934.5A CN106602999B (en) | 2016-12-21 | 2016-12-21 | A kind of Mixed cascading type photovoltaic inverter and control method based on super capacitor energy-storage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611192934.5A CN106602999B (en) | 2016-12-21 | 2016-12-21 | A kind of Mixed cascading type photovoltaic inverter and control method based on super capacitor energy-storage |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106602999A CN106602999A (en) | 2017-04-26 |
| CN106602999B true CN106602999B (en) | 2019-01-18 |
Family
ID=58602436
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611192934.5A Active CN106602999B (en) | 2016-12-21 | 2016-12-21 | A kind of Mixed cascading type photovoltaic inverter and control method based on super capacitor energy-storage |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106602999B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107910903A (en) * | 2017-09-06 | 2018-04-13 | 中南大学 | The distributing method for controlling power balance of series inverter under a kind of grid-connect mode |
| CN108183622A (en) * | 2018-02-28 | 2018-06-19 | 苏州唯控汽车科技有限公司 | More level tandem type inversion outputs-direct grid charging integration apparatus |
| CN110138007B (en) * | 2019-05-22 | 2022-11-04 | 南京理工大学 | Multi-mode operation control method of single-phase cascade type light storage and mixing system |
| CN112467770B (en) * | 2020-11-24 | 2022-12-20 | 珠海格力电器股份有限公司 | Photovoltaic energy storage power supply system and power supply control method thereof |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8772965B2 (en) * | 2010-06-29 | 2014-07-08 | General Electric Company | Solar power generation system and method |
| CN201910625U (en) * | 2010-10-14 | 2011-07-27 | 国网电力科学研究院 | Grid-connected photovoltaic inverter based on super capacitor |
| WO2013030236A2 (en) * | 2011-08-31 | 2013-03-07 | Optistring Technologies Ab | Dc-ac inverter for photovoltaic systems |
| ES2570356T3 (en) * | 2013-02-27 | 2016-05-18 | Optistring Tech Ab | DC Conversion Method - CA |
| UA107542C2 (en) * | 2014-01-24 | 2015-01-12 | Товариство З Обмеженою Відповідальністю "Техінвест-Еко" | METHOD AND APPARATUS FOR takeoff OF ELECTRICAL ENERGY from photoelectric module |
| CN105375512B (en) * | 2015-11-06 | 2018-01-30 | 重庆大学 | The power coordination control method of hybrid energy-storing in light storing cogeneration system |
| CN105356774A (en) * | 2015-12-09 | 2016-02-24 | 北京能源投资（集团）有限公司 | Converter used for hybrid energy storage system |
| CN106026164A (en) * | 2016-06-16 | 2016-10-12 | 上海电机学院 | Photovoltaic power generation system with energy storage apparatus |
-
2016
- 2016-12-21 CN CN201611192934.5A patent/CN106602999B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN106602999A (en) | 2017-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11552474B2 (en) | Multi-level medium voltage data center static synchronous compensator (DCSTATCOM) for active and reactive power control of data centers connected with grid energy storage and smart green distributed energy sources | |
| US10483759B2 (en) | Integrated multi-mode large-scale electric power support system for an electrical grid | |
| CN106602999B (en) | A kind of Mixed cascading type photovoltaic inverter and control method based on super capacitor energy-storage | |
| CN102640378B (en) | Distributed generator inverter is as the application of STATCOM | |
| Lahaçani et al. | Static compensator for maintaining voltage stability of wind farm integration to a distribution network | |
| Kow et al. | Power quality analysis for PV grid connected system using PSCAD/EMTDC | |
| Ahmad et al. | An approach to improve active power flow capability by using dynamic unified power flow controller | |
| CN102611108A (en) | Three-level three-phase four-wire active power filter and control method thereof | |
| Baran et al. | STATCOM with energy storage for smoothing intermittent wind farm power | |
| CN106410932B (en) | Chain type battery energy storage current transformer and control method suitable for middle straightening stream power distribution network | |
| CN103236800A (en) | Novel topological structure voltage source type inverter and adjusting method | |
| CN104218805A (en) | Unipolar-bipolar convertible direct-current converter | |
| CN101567573B (en) | Uninterrupted power and control method thereof | |
| CN108879783A (en) | A kind of electric power spring energy source consumption system | |
| Noroozian et al. | On-grid and off-grid operation of multi-input single-output DC/DC converter based fuel cell generation system | |
| Singh et al. | A new configuration of two-level 48-pulse VSCs based STATCOM for voltage regulation | |
| Azimi et al. | Circuit configuration of a sensorless multilevel inverter with voltage multiplying ability | |
| KR101281079B1 (en) | Photoelectric cell system with improved power quality and operating method of it | |
| Deepika et al. | Enhancement of voltage regulation using a 7-Level inverter based electric spring with reduced number of switches | |
| Vandoorn et al. | Soft curtailment for voltage limiting in low-voltage networks through reactive or active power droops | |
| Kabalci | Reactive power compensation in AC power systems | |
| CN103986184A (en) | Control system and control method for energy storage switch inductance type quasi-Z source single phase photovoltaic power generation | |
| Emarloo et al. | Examination and Comparison of Thyristor and Gate-Controlled Series Capacitors Performance for the Voltage Stabilization of Sensitive Loads | |
| CN108400607A (en) | A kind of power grid energy-storage system and its energy storage device balance control method | |
| Pham | Direct storage hybrid (DSH) inverter: A new concept of intelligent hybrid inverter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CB03 | Change of inventor or designer information |
Inventor after: Xiong Lan Inventor after: Peng Rui Inventor after: Gui Yuan Inventor before: Xiong Lan Inventor before: Gui Yuan |
|
| CB03 | Change of inventor or designer information |