CN109245160B - Light storage grid-connected control method and device for stabilizing photovoltaic power fluctuation - Google Patents
Light storage grid-connected control method and device for stabilizing photovoltaic power fluctuation Download PDFInfo
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- CN109245160B CN109245160B CN201811197464.0A CN201811197464A CN109245160B CN 109245160 B CN109245160 B CN 109245160B CN 201811197464 A CN201811197464 A CN 201811197464A CN 109245160 B CN109245160 B CN 109245160B
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- 238000000034 method Methods 0.000 title claims abstract description 47
- 230000000087 stabilizing effect Effects 0.000 title claims abstract description 31
- 239000003990 capacitor Substances 0.000 claims abstract description 51
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- 230000006641 stabilisation Effects 0.000 claims abstract description 12
- 238000011105 stabilization Methods 0.000 claims abstract description 12
- 230000003287 optical effect Effects 0.000 claims description 22
- 230000008859 change Effects 0.000 claims description 6
- 238000004590 computer program Methods 0.000 claims description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 27
- 229910052744 lithium Inorganic materials 0.000 description 27
- 238000010586 diagram Methods 0.000 description 17
- 238000010248 power generation Methods 0.000 description 13
- 238000007599 discharging Methods 0.000 description 9
- 238000004146 energy storage Methods 0.000 description 3
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- H02J3/383—
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- 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
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
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- 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
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- 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
- Y02E70/00—Other energy conversion or management systems reducing GHG emissions
- Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin
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Abstract
The invention relates to a light storage grid-connected control method and device for stabilizing photovoltaic power fluctuation. The method comprises the following steps: 1) collecting grid-connected voltage of the light-storage hybrid micro-grid system; 2) when the grid-connected voltage is greater than or equal to a first set value and less than or equal to a second set value, judging that the grid-connected voltage is in a normal grid-connected mode, performing first constant voltage control on the DC/AC, performing MPPT control on the photovoltaic DC/DC, performing first filtering stabilization control on the battery DC/DC, and performing hot standby control on the super capacitor DC/DC; 3) when the grid-connected voltage is lower than a first set value, the grid-connected mode is judged to be in a low-voltage grid-connected mode, reactive power given control and current limiting control are carried out on the DC/AC, power limiting control is carried out on the photovoltaic DC/DC, hot standby control is carried out on the battery DC/DC, and second constant voltage control is carried out on the super capacitor DC/DC. The invention finely controls DC/AC, photovoltaic DC/DC, battery DC/DC and super capacitor DC/DC in a normal grid-connected mode and a low-voltage grid-connected mode, and effectively restrains the power fluctuation of the light storage hybrid micro-grid system in the grid-connected mode.
Description
Technical Field
The invention belongs to the technical field of light storage grid-connected control, and particularly relates to a light storage grid-connected control method and device for stabilizing photovoltaic power fluctuation.
Background
In recent years, installed capacities of new energy resources such as photovoltaic power, wind power and the like are increased unprecedentedly, but due to inherent fluctuation, randomness and non-schedulability of distributed power generation, the stability of a power grid is challenged, a series of problems such as poor grid-connected electric energy quality and difficulty in absorption occur, and high permeability access and effective utilization of distributed power generation are limited.
Aiming at the problems encountered in the development of the distributed energy, the stored energy brings the light for people, can be used as a load to be charged when the electricity consumption is low, can be used as a power supply to be discharged when the electricity consumption is high, can effectively stabilize power fluctuation and cut peaks and fill valleys, can participate in frequency modulation and voltage regulation and demand response of a power grid, realizes large-scale high-permeability access of distributed power generation, and supports distributed power generation and a micro-grid.
The light-storage hybrid micro-grid system comprises a direct-current power supply system and an alternating-current power supply system, wherein the direct-current power supply system is composed of a photovoltaic power generation system and an energy storage system, the alternating-current power supply system is composed of a DC/AC converter, and the energy storage system comprises a battery system and/or a super capacitor system. For example, chinese patent application publication No. CN103078340A discloses a light storage hybrid micro-grid system including a photovoltaic power generation system, a battery system, a super capacitor system, and an ac power supply system. However, for the optical storage hybrid micro-grid system, the file does not effectively distinguish the grid-connected mode of the hybrid micro-grid system, and does not finely control the dc/dc converter corresponding to the storage battery, the dc/dc converter corresponding to the super capacitor, the dc/dc converter corresponding to the photovoltaic, and the dc/ac converter, so that the stable operation of the power grid in the grid-connected mode of the optical storage hybrid micro-grid system cannot be ensured.
Disclosure of Invention
The invention aims to provide a light storage grid-connected control method and device for stabilizing photovoltaic power fluctuation, which are used for solving the problem of large power grid fluctuation in the grid-connected mode of the existing light storage hybrid micro-grid system.
In order to solve the technical problems, the technical scheme of the invention is as follows:
the invention provides a light storage grid-connected control method for stabilizing photovoltaic power fluctuation, which aims at a light storage mixed micro-grid system and comprises a photovoltaic panel, a photovoltaic DC/DC converter connected with the photovoltaic panel, a battery DC/DC converter connected with the battery, a super capacitor and a super capacitor DC/DC converter connected with the super capacitor, wherein the photovoltaic DC/DC converter, the battery DC/DC converter and the super capacitor DC/DC converter are all used for being connected with an alternating current power grid through DC/AC converters, and the light storage grid-connected control method for stabilizing the photovoltaic power fluctuation comprises the following steps: 1) collecting grid-connected voltage of the light-storage hybrid micro-grid system; 2) when the grid-connected voltage of the light-storage hybrid micro-grid system is larger than or equal to a first set value and smaller than or equal to a second set value, the light-storage hybrid micro-grid system is judged to be in a normal grid-connected mode, first fixed voltage control is carried out on a DC/AC converter, MPPT control is carried out on a photovoltaic DC/DC converter, first filtering stabilization control is carried out on a battery DC/DC converter, and hot standby control is carried out on a super-capacitor DC/DC converter; 3) when the grid-connected voltage of the light storage mixed micro-grid system is lower than a first set value, the light storage mixed micro-grid system is judged to be in a low-voltage grid-connected mode, reactive power setting control and current limiting control are conducted on the DC/AC converter, power limiting control is conducted on the photovoltaic DC/DC converter, hot standby control is conducted on the battery DC/DC converter, and second voltage setting control is conducted on the super capacitor DC/DC converter.
The method has the beneficial effects that: the method realizes the fine control of DC/AC, photovoltaic DC/DC, battery DC/DC and super capacitor DC/DC in the light storage power generation system in a low-voltage grid-connected mode in a normal grid-connected mode, and effectively stabilizes the power fluctuation of the light storage hybrid micro-grid system in the grid-connected mode.
Further, when a scheduling instruction is received in a grid-connected mode, the invention further provides more refined control over DC/AC, photovoltaic DC/DC, battery DC/DC and super capacitor DC/DC in the optical storage power generation system, in the step 2), if the scheduling instruction is detected, the optical storage hybrid micro-grid system is judged to be in the scheduling grid-connected mode, the scheduling operation control is carried out on the DC/AC converter, the MPPT control is carried out on the photovoltaic DC/DC converter, the third constant voltage control is carried out on the battery DC/DC converter, and the second filtering stabilization control is carried out on the super capacitor DC/DC converter.
Further, the present invention proposes a method for achieving photovoltaic fluctuation power stabilization using a high-pass filter, and in order to improve the service life of a battery, the first filtering stabilization control is achieved by a high-pass filter, and a time constant of the high-pass filter changes according to a change in the remaining capacity of the battery.
Furthermore, the invention provides a specific method for adjusting the time constant of the high-pass filter according to the remaining capacity of the battery, so as to better improve the service life of the lithium battery, wherein the time constant of the high-pass filter changes according to the change of the remaining capacity of the battery as follows: when the battery is in a charging state, if the residual capacity of the battery is greater than or equal to a first residual capacity set value, controlling the time constant of the high-pass filter to be reduced along with the increase of the residual capacity of the battery; when the battery is in a discharging state, if the residual capacity of the battery is between the first residual capacity set value and the second residual capacity set value, the time constant for controlling the high-pass filter is reduced along with the reduction of the residual capacity of the battery.
The invention also provides a light storage grid-connected control device for stabilizing photovoltaic power fluctuation, which comprises a processor, a memory and a computer program which is stored on the memory and can run on the processor, wherein the processor executes the computer program to realize the following steps: 1) collecting grid-connected voltage of the light-storage hybrid micro-grid system; 2) when the grid-connected voltage of the light-storage hybrid micro-grid system is larger than or equal to a first set value and smaller than or equal to a second set value, the light-storage hybrid micro-grid system is judged to be in a normal grid-connected mode, first fixed voltage control is carried out on a DC/AC converter, MPPT control is carried out on a photovoltaic DC/DC converter, first filtering stabilization control is carried out on a battery DC/DC converter, and hot standby control is carried out on a super-capacitor DC/DC converter; 3) when the grid-connected voltage of the light storage mixed micro-grid system is lower than a first set value, the light storage mixed micro-grid system is judged to be in a low-voltage grid-connected mode, reactive power setting control and current limiting control are conducted on the DC/AC converter, power limiting control is conducted on the photovoltaic DC/DC converter, hot standby control is conducted on the battery DC/DC converter, and second voltage setting control is conducted on the super capacitor DC/DC converter.
The device of the invention has the following beneficial effects: the method realizes the fine control of DC/AC, photovoltaic DC/DC, battery DC/DC and super capacitor DC/DC in the light storage power generation system in a low-voltage grid-connected mode in a normal grid-connected mode, and effectively stabilizes the power fluctuation of the light storage hybrid micro-grid system in the grid-connected mode.
Further, when a scheduling instruction is received in a grid-connected mode, the invention further provides more refined control over DC/AC, photovoltaic DC/DC, battery DC/DC and super capacitor DC/DC in the optical storage power generation system, in the step 2), if the scheduling instruction is detected, the optical storage hybrid micro-grid system is judged to be in the scheduling grid-connected mode, the scheduling operation control is carried out on the DC/AC converter, the MPPT control is carried out on the photovoltaic DC/DC converter, the third constant voltage control is carried out on the battery DC/DC converter, and the second filtering stabilization control is carried out on the super capacitor DC/DC converter.
Further, the present invention proposes an apparatus for achieving photovoltaic fluctuating power smoothing using a high-pass filter, and in order to improve the service life of a battery, the first filtering smoothing control is achieved by a high-pass filter whose time constant changes according to a change in the remaining capacity of the battery.
Furthermore, the invention provides a specific method for adjusting the time constant of the high-pass filter according to the remaining capacity of the battery, so as to better improve the service life of the lithium battery, wherein the time constant of the high-pass filter changes according to the change of the remaining capacity of the battery as follows: when the battery is in a charging state, if the residual capacity of the battery is greater than or equal to a first residual capacity set value, controlling the time constant of the high-pass filter to be reduced along with the increase of the residual capacity of the battery; when the battery is in a discharging state, if the residual capacity of the battery is between the first residual capacity set value and the second residual capacity set value, the time constant for controlling the high-pass filter is reduced along with the reduction of the residual capacity of the battery.
Drawings
Fig. 1 is a schematic structural diagram of a conventional optical storage hybrid micro-grid system;
fig. 2 is a schematic diagram of a control method of the DC/AC converter in the normal grid-connected mode in embodiment 1 of the method of the present invention;
fig. 3 is a schematic diagram of a control method of the photovoltaic DC/DC converter in the normal grid-connected mode in embodiment 1 of the method of the present invention;
fig. 4 is a schematic diagram of a control method of the battery DC/DC converter in the normal grid-connected mode in embodiment 1 of the method of the present invention;
fig. 5 is a schematic diagram of a control method of the super capacitor DC/DC converter in a normal grid-connected mode in embodiment 1 of the method of the present invention;
fig. 6 is a circuit diagram of a high-pass filter in the normal grid-connected mode in embodiment 1 of the method of the present invention;
fig. 7 is a battery SOC-time constant curve diagram in the normal grid-connection mode in embodiment 1 of the method of the present invention;
fig. 8 is a schematic diagram of a method for controlling a DC/AC converter in a low-voltage grid-connected mode according to embodiment 1 of the method of the present invention;
fig. 9 is a schematic diagram of a control method of the photovoltaic DC/DC converter in the low-voltage grid-connected mode in embodiment 1 of the method of the present invention;
fig. 10 is a schematic diagram of a method for controlling a battery DC/DC converter in a low-voltage grid-connected mode according to embodiment 1 of the present invention;
fig. 11 is a schematic diagram of a control method of the super capacitor DC/DC converter in the low-voltage grid-connected mode in embodiment 1 of the method of the present invention;
fig. 12 is a control logic diagram of three grid-connected modes in embodiment 2 of the method of the present invention;
fig. 13 is a schematic diagram of a method for controlling a DC/AC converter in a scheduling grid-connected mode according to embodiment 2 of the present invention;
fig. 14 is a schematic diagram of a method for controlling a battery DC/DC converter in a scheduling grid-connected mode according to embodiment 2 of the method of the present invention;
fig. 15 is a schematic diagram of a method for controlling a super capacitor DC/DC converter in a scheduling grid-connected mode in embodiment 2 of the method of the present invention.
Detailed Description
The following further describes embodiments of the present invention with reference to the drawings.
The light storage grid-connected control method for stabilizing photovoltaic power fluctuation is explained by taking an energy storage system comprising a lithium battery system and a super capacitor system as an example, the structural schematic diagram of a corresponding light storage hybrid micro-grid is shown in fig. 1, the light storage hybrid micro-grid comprises a photovoltaic panel, a photovoltaic DC/DC converter connected with the photovoltaic panel, a lithium battery, a battery DC/DC converter connected with the battery, a super capacitor and a super capacitor DC/DC converter connected with the super capacitor, and the photovoltaic DC/DC converter, the battery DC/DC converter and the super capacitor DC/DC converter are all connected with an alternating current grid through DC/AC converters.
the light storage grid-connected control method for stabilizing photovoltaic power fluctuation in the embodiment comprises the following steps: grid-connected voltage of the light storage hybrid micro-grid system is collected, and whether the light storage hybrid micro-grid system is in a normal grid-connected mode or a low-voltage grid-connected mode is judged according to the range of the grid-connected voltage.
When the grid-connected voltage of the optical storage hybrid micro-grid system is larger than or equal to a first set value and smaller than or equal to a second set value, the optical storage hybrid micro-grid system is judged to be in a normal grid-connected mode, first constant voltage control is carried out on a DC/AC converter, and a voltage outer ring is provided with a given direct-current bus voltage value UDCrefAnd the actually acquired voltage value U of the direct current busDCMaking difference, and outputting active given current value by the difference value through a PI (proportional-integral) controller
Idle given current value
According to the actual situation, the inner ring is set, and dq decoupling control is adopted to realize grid-connected current control, as shown in fig. 2; MPPT control, i.e. maximum power point control, of a photovoltaic DC/DC converter is performed by collecting the voltage U output by a photovoltaic arrayPVAnd current iPVThe output voltage U of the photovoltaic array is measured by maximum power point algorithm (MPPT)mpptAdjusted to the optimum position and the actual photovoltaic array output voltage UPVMaking a difference, and outputting a duty ratio through a PI controller to control a photovoltaic DC/DC module so as to finally realize the maximum power output of the photovoltaic array, as shown in FIG. 3; the first frequency stabilizing control, namely the medium-high frequency stabilizing control, is carried out on the battery DC/DC converter, namely the low-frequency signal of the photovoltaic output power is filtered by a high-pass filter, and the medium-high frequency signal is obtained and used as the given power P of the lithium battery DC/DCbatrefDividing the current voltage of the lithium battery by the current voltage of the lithium battery to obtain a given output current i* batAnd then outputs the current i with the actual DC/DC output current on the lithium battery sidebatPerforming difference, outputting a variable duty ratio through PI control, and finally controlling a lithium battery DC/DC to realize medium-high frequency power stabilization of the optical storage system, as shown in FIG. 4; the hot standby control is carried out on the super capacitor DC/DC converter, which means that the super capacitor is at the momentDC/DC is active, but the output current is zero,
setting charging and discharging current for the super capacitor side DC/DC, iCThe actual charging and discharging current is the super capacitor side DC/DC, as shown in FIG. 5.
In a normal grid-connected mode, medium-high frequency stabilizing control on a lithium battery DC/DC converter is mainly realized through a high-pass filter, photovoltaic medium-frequency and high-frequency power signals output by the photovoltaic output power through the high-pass filter are used for charging a positive lithium battery and discharging a negative lithium battery, and a linear relation between a time constant tau and a lithium battery SOC is established. FIG. 6 is a circuit diagram of a second order high pass filter according to which a transfer function H(s) is established:
order: the time constant tau is RC,
cut-off frequency of pass band
The passband cut-off frequency is inversely proportional to the time constant, the smaller the time constant is, the larger the passband cut-off frequency is, and the smaller the power compensated by the lithium battery is.
An SOC-tau working curve is drawn according to the principle, as shown in FIG. 7, when the battery is in a charging state and the remaining capacity of the battery is less than a first remaining capacity set value a, the time constant of the high-pass filter is tau2＝R2C2(ii) a If the residual capacity of the battery is greater than or equal to the first residual capacity set value a, the time constant for controlling the high-pass filter is reduced along with the increase of the residual capacity of the batteryIs small.
When the battery is in a discharging state and the residual capacity of the battery is larger than a second residual capacity set value c, the time constant of the high-pass filter is tau2＝R2C2(ii) a If the residual battery capacity is between the first residual capacity set value a and the second residual capacity set value c, controlling the time constant of the high-pass filter to be reduced along with the reduction of the residual battery capacity; when the residual capacity of the battery is less than the first residual capacity set value a, the time constant of the high-pass filter is tau1＝R1C1. And designing a lithium battery charging curve equation and a lithium battery discharging curve equation according to the figure 7.
Lithium battery charging curve equation:
lithium battery discharge curve equation:
when the grid-connected voltage of the light-storage mixed micro-grid system is lower than a first set value, the light-storage mixed micro-grid system is judged to be in a low-voltage grid-connected mode, reactive power given control and current limiting control are carried out on a DC/AC converter,
edfor the effective value of the network phase voltage, P*The active power which is actually required to be output is provided, so that the actual output active power and the actual output reactive power are respectively given by actual conditions, and the inner loop control is dq decoupling control, as shown in fig. 8; the power limiting control of the photovoltaic DC/DC converter refers to increasing or decreasing U through an MPPT power limiting algorithmmpptThe purpose of limiting the photovoltaic output power is achieved, as shown in fig. 9; performing hot standby control on the battery DC/DC converter, wherein the control current on the lithium battery side is set to be zero, and at the moment, the lithium battery DC/DC converter is in an operating state, but does not output current, as shown in FIG. 10; to super capacitor DCThe second constant voltage control is performed by the/DC converter, which means that the voltage outer ring adopts a stable DC bus voltage, the current inner ring controls the output of the current at the side of the super capacitor, and finally the purpose of stabilizing the DC bus voltage is achieved by controlling the PWM duty ratio, as shown in fig. 11.
In the present embodiment, a lithium battery is used, and as another embodiment, a lead-acid battery or the like may be used.
In this example, a is 10%, b is 95%, and c is 97%; in another embodiment, values close to the above values may be used, such as 10.1% for a, 94.9% for b, and 97.2% for c.
In the embodiment, a linear relation between the time constant tau of the second-order high-pass filter and the SOC of the lithium battery is established, as other implementation modes, the first-order high-pass filter, the third-order high-pass filter and the like can be adopted, and when the first-order high-pass filter and the third-order high-pass filter are adopted, the corresponding time constants are adjusted according to the residual electric quantity of the lithium battery; in addition, instead of adjusting the time constant τ of the intermediate stage according to the above linear relationship, a plurality of piecewise time constants may be set according to the remaining capacity of the lithium battery in the intermediate stage.
The method for fixing the time constant in the middle stage is abandoned, the flexibility is improved, and the service life of the lithium battery is prolonged.
According to the embodiment, the DC/AC, the photovoltaic DC/DC, the battery DC/DC and the super capacitor DC/DC in the optical storage power generation system are finely controlled in the low-voltage grid-connected mode in the normal grid-connected mode, and the power fluctuation of the optical storage hybrid micro-grid system in the grid-connected mode is effectively suppressed.
Embodiment 2 of the grid-connected control method for stabilizing photovoltaic power fluctuation:
the difference between this embodiment and the above embodiment is that this embodiment further includes fine control in the scheduling grid-connected mode, as shown in fig. 12.
When the grid-connected voltage of the optical storage hybrid micro-grid system is larger than or equal to a first set value and smaller than or equal to a second set value, if a scheduling instruction exists, the optical storage power generation system is judged to be in a scheduling grid-connected mode, and scheduling operation control is carried out on the DC/AC converterWhen receiving the output instruction of the superior dispatching system, the active output P can be set according to the requirementrefAnd reactive power
As shown in fig. 13; MPPT control is still performed on the photovoltaic DC/DC converter, as shown in fig. 3; performing stable DC bus voltage control on the lithium battery DC/DC converter, i.e. third constant voltage control, which means that the voltage outer ring adopts stable DC bus voltage, the current inner ring controls the output of current at the side of the lithium battery, and finally the purpose of stabilizing the DC bus voltage is achieved by controlling the PWM duty ratio, as shown in fig. 14; carrying out second frequency stabilizing control, namely high-frequency stabilizing control on the super-capacitor DC/DC converter, and obtaining a high-frequency signal P of photovoltaic power through a high-pass filterCrefAnd obtaining the given charging and discharging current of the DC/DC at the side of the super capacitor through calculation
And the actual charging and discharging current i of the super capacitor side DC/DCcAnd (3) performing difference making, adjusting by a PI controller, outputting a modulation wave, controlling and outputting a variable duty ratio by PWM, and finally realizing the control of the given output power of the super capacitor, as shown in FIG. 15. The super capacitor DC/DC converter is subjected to high-frequency stabilizing control, the bandwidth of a filtering signal can be reduced by setting the passband cut-off frequency of the high-pass filter, and the high-frequency signal filtering effect is realized.
According to the embodiment, the DC/AC, the photovoltaic DC/DC, the battery DC/DC and the super capacitor DC/DC in the optical storage power generation system are finely controlled in the low-voltage grid-connected mode in the scheduling grid-connected mode, and the power fluctuation of the optical storage hybrid micro-grid system in the grid-connected mode is effectively suppressed.
Light storage grid-connected control device embodiment for stabilizing photovoltaic power fluctuation
The optical storage grid-connected control device for stabilizing photovoltaic power fluctuation in the embodiment comprises a processor, a memory and a computer program which is stored on the memory and can run on the processor, wherein the processor executes the computer program to realize the steps in the embodiment of the optical storage grid-connected control method for stabilizing photovoltaic power fluctuation.
Since the related steps have been described in detail in the embodiment of the light storage grid-connected control method for stabilizing photovoltaic power fluctuation, no further description is given here.
Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (4)
1. A light storage grid-connected control method for stabilizing photovoltaic power fluctuation comprises a photovoltaic panel, a photovoltaic DC/DC converter connected with the photovoltaic panel, a battery DC/DC converter connected with the battery, a super capacitor and a super capacitor DC/DC converter connected with the super capacitor, wherein the photovoltaic DC/DC converter, the battery DC/DC converter and the super capacitor DC/DC converter are all connected with an alternating current power grid through DC/AC converters, and is characterized in that the light storage grid-connected control method for stabilizing photovoltaic power fluctuation comprises the following steps:
1) collecting grid-connected voltage of the light-storage hybrid micro-grid system;
2) when the grid-connected voltage of the light-storage hybrid micro-grid system is larger than or equal to a first set value and smaller than or equal to a second set value, the light-storage hybrid micro-grid system is judged to be in a normal grid-connected mode, first fixed voltage control is carried out on a DC/AC converter, MPPT control is carried out on a photovoltaic DC/DC converter, first filtering stabilization control is carried out on a battery DC/DC converter, and hot standby control is carried out on a super-capacitor DC/DC converter;
3) when the grid-connected voltage of the light storage mixed micro-grid system is lower than a first set value, the light storage mixed micro-grid system is judged to be in a low-voltage grid-connected mode, reactive power setting control and current limiting control are carried out on a DC/AC converter, power limiting control is carried out on a photovoltaic DC/DC converter, hot standby control is carried out on a battery DC/DC converter, and second voltage setting control is carried out on a super capacitor DC/DC converter;
the first filtering stabilizing control is realized by a second-order high-pass filter, and the second-order high-pass filter is sequentially provided with two RC branches from an input end to an output end; the time constant of the second-order high-pass filter changes according to the change of the residual capacity of the battery, and when the battery is in a charging state:
when the battery is in a discharge state:
2. The optical storage grid-connected control method for stabilizing photovoltaic power fluctuation according to claim 1, wherein in the step 2), if a scheduling instruction is detected, it is determined that the optical storage hybrid microgrid system is in a scheduling grid-connected mode, the DC/AC converter is controlled according to the scheduling instruction, MPPT control is performed on the photovoltaic DC/DC converter, third constant voltage control is performed on the battery DC/DC converter, and second filtering stabilization control is performed on the super capacitor DC/DC converter.
3. A grid-connected photovoltaic control apparatus for stabilizing photovoltaic power fluctuation, the apparatus comprising a processor and a memory, and a computer program stored in the memory and operable on the processor, the processor implementing the following steps when executing the computer program:
1) collecting grid-connected voltage of the light-storage hybrid micro-grid system;
2) when the grid-connected voltage of the light-storage hybrid micro-grid system is larger than or equal to a first set value and smaller than or equal to a second set value, the light-storage hybrid micro-grid system is judged to be in a normal grid-connected mode, first fixed voltage control is carried out on a DC/AC converter, MPPT control is carried out on a photovoltaic DC/DC converter, first filtering stabilization control is carried out on a battery DC/DC converter, and hot standby control is carried out on a super-capacitor DC/DC converter;
3) when the grid-connected voltage of the light storage mixed micro-grid system is lower than a first set value, the light storage mixed micro-grid system is judged to be in a low-voltage grid-connected mode, reactive power setting control and current limiting control are carried out on a DC/AC converter, power limiting control is carried out on a photovoltaic DC/DC converter, hot standby control is carried out on a battery DC/DC converter, and second voltage setting control is carried out on a super capacitor DC/DC converter;
the first filtering stabilizing control is realized by a second-order high-pass filter, and the second-order high-pass filter is sequentially provided with two RC branches from an input end to an output end; the time constant of the second-order high-pass filter changes according to the change of the residual capacity of the battery, and when the battery is in a charging state:
when the battery is in a discharge state:
4. The grid-connected optical storage control device for stabilizing photovoltaic power fluctuation according to claim 3, wherein in the step 2), if a scheduling instruction is detected, it is determined that the hybrid optical storage microgrid system is in a scheduling grid-connected mode, the DC/AC converter is controlled according to the scheduling instruction, the MPPT control is performed on the photovoltaic DC/DC converter, the third constant voltage control is performed on the battery DC/DC converter, and the second filtering stabilization control is performed on the super capacitor DC/DC converter.
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