CN113422378A - Comprehensive energy system of energy hub - Google Patents
Comprehensive energy system of energy hub Download PDFInfo
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- CN113422378A CN113422378A CN202110696443.9A CN202110696443A CN113422378A CN 113422378 A CN113422378 A CN 113422378A CN 202110696443 A CN202110696443 A CN 202110696443A CN 113422378 A CN113422378 A CN 113422378A
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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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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
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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
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
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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
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
- H02J9/061—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for DC powered loads
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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
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
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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
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/28—The renewable source being wind energy
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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
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B10/00—Integration of renewable energy sources in buildings
- Y02B10/70—Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
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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
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
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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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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention relates to a comprehensive energy system of an energy hub, which comprises a power generation unit, an energy storage battery pack and a control unit, wherein the energy storage battery pack is arranged at an outlet of the power generation unit, the power generation unit is connected to a bus through a feeder, the control unit switches and adjusts the working state of the energy storage battery pack, overshooting and overdischarging of the energy storage battery pack are protected, power tracking is carried out on the power generation unit, a controller of the control unit adopts an energy storage smoothing control strategy, variable time constant control is carried out on the charge state of the energy storage battery pack on the basis of a low-pass filtering smoothing control strategy, and fuzzy control is introduced; the comprehensive energy system provided by the invention forms a wind-solar hybrid power generation system, and adopts an energy storage smoothing control strategy, so that the energy storage battery pack can stabilize the fluctuation of the output power of wind power and solar power generation, and the service life of the energy storage battery pack is taken into consideration.
Description
Technical Field
The invention belongs to the technical field of multi-energy systems, and particularly relates to a comprehensive energy system of an energy hub.
Background
The traditional large power grid mainly adopts a power supply mode of centralized power generation and remote power transmission, the influence range is expanded when a power grid accident occurs, the requirements of users on higher and higher safety and reliability of electric energy are difficult to meet, under the common pressure of energy crisis, environmental problems and power requirements, new energy power generation becomes an important method for solving the contradictions, distributed power sources form a micro-grid system for combined power generation and control, the characteristics of distributed power sources such as dispersion and random variation can be effectively solved, and the benefit of distributed power generation can be improved. The microgrid is a small-sized power generation and distribution system composed of a distributed power supply, an energy conversion device, a load and protection device, a monitoring system and the like, and as the application of the microgrid is gradually increased and the installation capacity is continuously increased, the research of a control strategy becomes a very critical link.
Due to the uncertainty of wind and light energy sources, a wind power generation system and a photovoltaic power generation system cannot stably supply power, so that the energy storage battery pack is difficult to smooth the fluctuation of the output power of an intermittent power source through regular energy absorption and release. Therefore, the energy storage battery pack can maximally suppress the fluctuation of the wind power and solar power generation output power within a limited capacity range only by making a reasonable smooth control strategy, and simultaneously, the service life of the energy storage battery pack is considered.
Disclosure of Invention
The invention aims to solve the problems in the background art, and provides a comprehensive energy system of an energy hub, which converges the generated energy of wind and light resources together and then uniformly supplies the collected generated energy to a load to form a wind-solar hybrid power generation system, and adopts an energy storage smooth control strategy to ensure that an energy storage battery pack stabilizes the fluctuation of the output power of wind power generation and solar power generation and also considers the service life of the energy storage battery pack.
The purpose of the invention is realized as follows:
a comprehensive energy system of an energy hub comprises a power generation unit, an energy storage battery pack and a control unit, wherein the energy storage battery pack is arranged at an outlet of the power generation unit, the power generation unit is connected to a bus through a feeder line, the power generation unit comprises a wind-electricity and light-electricity complementary power supply system consisting of a photovoltaic array and a wind generating set, and the control unit switches and adjusts the working state of the energy storage battery pack, protects the overshoot and the over-discharge of the energy storage battery pack and tracks the power of the power generation unit;
the controller of the control unit adopts an energy storage smoothing control strategy, controls the charge state of the energy storage battery pack by a variable time constant on the basis of a low-pass filtering smoothing control strategy, introduces fuzzy control and improves the automatic adjustment capability of the SOC.
Preferably, the output end of the wind generating set is provided with an unloading circuit which is used as a protection circuit of the wind generating set.
Preferably, the energy storage battery pack is a hybrid energy storage battery pack consisting of two layers of energy storage, wherein the first layer of energy storage pack is mainly used for smoothing power components with rapid fluctuation and is suitable for energy storage with rapid response, such as flywheel energy storage, super capacitor energy storage, superconducting energy storage and some chemical batteries, and the second layer of energy storage pack is mainly used for smoothing power components with slow fluctuation speed and is suitable for energy storage with slow response, such as pumped storage energy storage, compressed air energy storage, thermal energy storage and partial chemical energy storage.
Preferably, the controller of the control unit comprises a voltage detection circuit module and a current detection circuit module, the electric energy generated by the wind generating set is rectified by three phases to output direct current as one path of a double input circuit, and the photovoltaic array generates electricity as the other path of the double input circuit and is converted into stable direct current by a double input Boost circuit to be supplied to the energy storage battery pack and the load.
Preferably, the electric energy generated by the wind generating set is converted into electric energy for charging the energy storage battery pack through an alternating current-direct current conversion circuit in the wind power generating circuit under the control of a single chip microcomputer of the controller, and the electric energy is supplied to a load;
the electric energy generated by the photovoltaic array is converted into the electric energy for charging the energy storage battery pack under the control of the singlechip of the controller through the direct current voltage stabilizer circuit in the light energy power generation circuit, and the electric energy is supplied to a load.
Preferably, the grid-connected operation mode is entered when the controller of the control unit detects that the access point voltage of the power generation unit is higher than the access point allowable minimum voltage, and the island operation mode is entered when the controller of the control unit detects that the access point voltage of the power generation unit is lower than the access point allowable minimum voltage.
Preferably, the energy storage smoothing control strategy is based on the existing low-pass filtering smoothing control strategy, the SOC variable time constant is controlled, fuzzy control is introduced, the automatic adjustment capability of the SOC is improved, and the out-of-limit condition of the SOC of the energy storage battery pack is reduced.
Preferably, the control unit of the invention changes the amplitude of the output power of the wind power generation and the photovoltaic power generation by charging and discharging the storage battery of the energy storage battery pack, so that the power injected into the power distribution network is more stable, and in the energy storage smooth control strategy based on the low-pass filtering principle, in the low-pass filtering control of the timing constant, the target output power P of the energy storage battery pack after the low-pass filtering is performed0Satisfies the following conditions:
P0=[1/（1+τs）]×Pwp(ii) a Wherein P iswpThe total output power of the wind power and the photovoltaic power generation is shown, tau is a smoothing time constant of the energy storage battery pack, and s is a differential operator;
according to power balance having PB=P0-Pwp，PBFor the power absorbed or discharged by the energy-storage battery, when PBWhen the power is more than 0, the energy storage battery pack discharges power, and when P is greater than 0BWhen the power is less than 0, the energy storage battery pack absorbs power;
at tkAt time = kt (k =1,2,3 … n), there are:
P0(k)=[τ/(τ+t)]×P0(k-1)+[t/(τ+t)]×Pwp(k)，P0(k) and P0(k-1) represents the power injected into the power grid by the energy storage battery pack at the kt moment and the (k-1) t moment respectively, and Pwp(k) The total output power of the wind power and the photovoltaic power generation at the kt moment;
then there is P0(k)-P0(k-1)=tPB(k) τ, the smoothing time constant τ therefore ranges from:
τ≥∣tPB(k)/ΔPB∣。
preferably, the capacity of the energy storage battery pack is set as EBThen, there are:
EB(k)=[τtPwp(k)+τEB(k-1)]/(τ+t)，EB(k) and EBAnd (k-1) represents the electric quantity of the energy storage battery pack at the kt moment and the (k-1) t moment respectively.
Preferably, the energy storage smoothing control strategy comprises the following steps:
a1, adjusting the smoothing time constant tau of the first-order low-pass filter in real time on line according to the capacity of the energy storage battery pack;
a2, total power output value P of power generation unitwpAfter first-order low-pass filtering, according to PB=P0-PwpCalculating to obtain a given reference value P of the output of the energy storage battery packB-refSo as to obtain the smoothed power value P merged into the power distribution network0；
A3, adding an SOC active regulator, and adding a power adjustment quantity delta P after a filter with a variable time constant when the power change rate of the power generation unit is smallBThe energy storage battery pack can be quickly restored to a reasonable range, the service life of the battery is prolonged, and the smooth control effect is improved.
Preferably, let SOChighFor maximum state of charge, SOC, of the safe operating zone of the energy storage battery packlowFor energy storage batteriesMinimum state of charge, SOC, of group safe operating areamaxIs the critical value of the higher region of the SOC of the energy storage battery pack, SOCminThe time constant of the basic low-pass filtering smoothing control strategy is tau for the critical value of the SOC overcharge region of the energy storage battery pack0，τcTime constant, τ, for charging energy storage battery packfTime constant, k, for discharging an energy storage battery1、k2、k3Respectively representing the change rate of the smoothing time constant in different intervals, the following are provided:
s1, current SOCmaxWhen the SOC (k) is less than or equal to 100 percent, the working SOC of the energy storage battery pack enters an overcharge region, which is a one-way working region, the energy storage battery pack is forbidden to be charged, and only the energy storage battery pack is allowed to be discharged, and the method comprises the following steps:
s1-1, when PBLet the smoothing time constant tau be less than 0c=0, preventing overcharge of the energy storage battery pack;
s1-2, when PBWhen > 0, let the smoothing time constant tauf=k1[SOC(t)-SOCmax]+τ0Discharging the energy storage battery pack;
s2, current SOChigh≤SOC(k)＜SOCmaxDuring, for the higher interval of SOC, the energy storage group battery is less charged, and discharge more, then have:
s2-1, when PBLet the smoothing time constant tau be less than 0c=k2[SOC(t)-SOChigh]+τ0Limiting charging of the energy storage battery pack;
s2-2, when PBWhen > 0, let the smoothing time constant tauf=k3[SOC(t)-SOChigh]+τ0The energy storage battery pack discharges more;
s3, current SOClow＜SOC(k)＜SOChighThen, for the SOC safe working area, the smooth control strategy is processed according to the low-pass filtering control strategy of the timing constant, and let tauc=τf=τ0The output of the energy storage battery pack is reduced;
s4, current SOCmin＜SOC(k)≤SOClowDuring, for the interval that SOC is lower, the energy storage group battery charges more, discharges less, then has:
s4-1, when PBLet the smoothing time constant tau be less than 0c=k3[SOClow-SOC(t)]+τ0Charging the energy storage battery pack more;
s4-2, when PBWhen > 0, let the smoothing time constant tauf=k2[SOClow-SOC(t)]+τ0Limiting discharge of the energy storage battery pack;
s5, when 0% < SOC (k) ≦ SOCminDuring the time, get into SOC and cross the interval of putting, for one-way workspace, forbid the energy storage group battery and discharge, only allow its to charge, then have:
s5-1, when PBLet the smoothing time constant tau be less than 0c=k1[SOCmin-SOC(t)]+τ0Charging the energy storage battery pack more;
s5-2, when PBWhen > 0, let the smoothing time constant taufAnd =0, preventing the energy storage battery pack from over-discharging.
Preferably, the SOC active regulator adopts a fuzzy control algorithm and corrects the output P of the energy storage batteryB-refAnd active regulation control of the energy storage battery pack when the SOC is too high or too low is realized.
Compared with the prior art, the invention has the beneficial effects that:
1. the comprehensive energy system of the energy hub adopts an energy storage smooth control strategy to enable an energy storage battery pack to stabilize the fluctuation of the output power of wind power and solar power generation and take the service life of a storage battery of the energy storage battery pack into consideration, the energy storage smooth control strategy is to control an SOC variable time constant on the basis of the existing low-pass filtering smooth control strategy, and a fuzzy control SOC active regulator is introduced to improve the automatic regulation capability of the SOC and reduce the out-of-limit condition of the SOC of the energy storage battery pack.
2. The invention provides a comprehensive energy system of an energy hub, which takes wind power generation and solar power generation as energy sources of a whole power supply system, the principle of the wind power generation system is that wind energy is firstly converted into mechanical energy, then the mechanical energy drives a generator, finally the generator outputs alternating current, the alternating current is processed by an AC/DC rectifier to obtain direct current, then a DC/DC converter obtains stable voltage, a solar panel absorbs the solar energy and converts the solar energy into the direct current, the stable voltage is obtained by the DC/DC converter, a sub-control unit supplies the obtained electric energy to a load group, if the electric energy is surplus under the condition of satisfying the normal work of the load group, the surplus electric energy is stored in an energy storage battery pack, and when a storage battery pack in the energy storage battery pack is fully filled, the surplus electric energy is unloaded by an unloading circuit, avoiding damage to the equipment.
3. According to the comprehensive energy system of the energy hub, the energy storage battery pack is centrally arranged at the outlet of the power generation unit, so that the wide area smoothing function of the wind power generator group and the natural complementarity of wind power generation and photovoltaic power generation can be better utilized, the capacity of required energy storage can be reduced, and the cost is saved.
Drawings
Fig. 1 is a schematic diagram of an integrated energy system of an energy hub according to the present invention.
Fig. 2 is a schematic diagram of a control unit of an integrated energy system of an energy hub according to the present invention.
Fig. 3 is a schematic circuit diagram of a control unit of an integrated energy system of an energy hub according to the present invention.
Fig. 4 is a schematic diagram of a controller for an integrated energy system of an energy hub according to the present invention.
Fig. 5 is a schematic diagram of the energy storage smoothing control strategy of the integrated energy system of the energy hub.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by those skilled in the art without any creative work based on the embodiments of the present invention belong to the protection scope of the present invention.
Example 1
With reference to fig. 1, an integrated energy system of an energy hub includes a power generation unit, an energy storage battery pack, and a control unit, where the energy storage battery pack is configured at an outlet of the power generation unit, the power generation unit is connected to a bus through a feeder, the power generation unit includes a wind-electricity and light-electricity complementary power supply system composed of a photovoltaic array and a wind power generator set, and the control unit switches and adjusts a working state of the energy storage battery pack, protects overshoot and overdischarge of the energy storage battery pack, and tracks power of the power generation unit.
The output end of the wind generating set is provided with an unloading circuit which is used as a protection circuit of the wind generating set.
The energy storage battery pack is a hybrid energy storage battery pack consisting of two layers of energy storage, wherein the first layer of energy storage pack is mainly used for smoothing power components with rapid fluctuation and is suitable for using energy storage with rapid response, such as flywheel energy storage, super capacitor energy storage, superconducting energy storage and some chemical batteries for energy storage, and the second layer of energy storage pack is mainly used for smoothing power components with slower fluctuation speed and is suitable for using energy storage with slow response, such as pumped storage energy storage, compressed air energy storage, thermal energy storage and partial chemical energy storage.
Wind power generation and solar power generation are used as energy sources of the whole power supply system, the principle of the wind power generation system is that wind energy is firstly converted into mechanical energy, then the mechanical energy drives a generator, finally the generator outputs alternating current, the alternating current is processed by an AC/DC rectifier to obtain direct current, stable voltage is obtained by a DC/DC converter, solar panels absorb and convert the solar energy into the direct current, the stable voltage is obtained by the DC/DC converter, a branch control unit supplies the obtained electric energy to a load group, if the electric energy is surplus under the condition that the normal work of the load group is met, the surplus electric energy is stored in an energy storage battery pack, and when a storage battery pack in the energy storage battery pack is fully charged, the surplus electric energy is unloaded by an unloading circuit, so that the damage to equipment is avoided.
Example 2
With reference to fig. 1-4, the electric energy generated by the wind generating set is converted into electric energy for charging the energy storage battery pack through an ac/dc conversion circuit in the wind power generating circuit under the control of a single chip of the controller, and is supplied to a load; the electric energy generated by the photovoltaic array is converted into the electric energy for charging the energy storage battery pack under the control of the singlechip of the controller through the direct current voltage stabilizer circuit in the light energy power generation circuit, and the electric energy is supplied to a load.
The controller of the control unit comprises a voltage detection circuit module and a current detection circuit module, electric energy generated by the wind generating set is rectified by three phases to output direct current as one path of a double input circuit, and the photovoltaic array generates electricity as the other path of the double input circuit and becomes stable direct current to supply to an energy storage battery pack and a load through a double input Boost circuit.
The working steps of the control unit are as follows:
1) the output voltage of the power generation unit is controlled at the maximum power point voltage through the DC/DC converter, and the maximum power output of the power generation unit is realized;
2) delivering the electric energy to an energy storage battery pack or a load;
3) the control of the energy storage battery is realized through the charge and discharge circuit of the energy storage battery pack, and the storage battery of the energy storage battery pack is ensured not to be over-charged and over-discharged to influence the service life of the storage battery.
Example 3
With reference to fig. 5, the controller of the control unit adopts an energy storage smoothing control strategy, and on the basis of the low-pass filtering smoothing control strategy, the controller controls the state of charge of the energy storage battery pack by a variable time constant, introduces fuzzy control, and improves the automatic adjustment capability of the SOC.
The energy storage smoothing control strategy comprises the following steps:
a1, adjusting the smoothing time constant tau of the first-order low-pass filter in real time on line according to the capacity of the energy storage battery pack;
a2, total power output value P of power generation unitwpAfter first-order low-pass filtering, according to PB=P0-PwpCalculating to obtain a given reference value P of the output of the energy storage battery packB-refSo as to obtain the smoothed power value P merged into the power distribution network0；
A3, adding an SOC active regulator, and adding a power adjustment quantity delta P after a filter with a variable time constant when the power change rate of the power generation unit is smallBThe energy storage battery pack can be quickly restored to a reasonable range, the service life of the battery is prolonged, and the smooth control effect is improved.
The control unit of the invention changes the amplitude of the wind power and photovoltaic power generation output power by charging and discharging the storage battery of the energy storage battery pack, so that the power injected into the power distribution network is more stable, in the energy storage smooth control strategy based on the low-pass filtering principle, in the low-pass filtering control of the timing constant, the target output power P of the energy storage battery pack after the low-pass filtering is carried out0Satisfies the following conditions:
P0=[1/（1+τs）]×Pwp(ii) a Wherein P iswpThe total output power of the wind power and the photovoltaic power generation is shown, tau is a smoothing time constant of the energy storage battery pack, and s is a differential operator;
according to power balance having PB=P0-Pwp，PBFor the power absorbed or discharged by the energy-storage battery, when PBWhen the power is more than 0, the energy storage battery pack discharges power, and when P is greater than 0BWhen the power is less than 0, the energy storage battery pack absorbs power;
at tkAt time = kt (k =1,2,3 … n), there are:
P0(k)=[τ/(τ+t)]×P0(k-1)+[t/(τ+t)]×Pwp(k)，P0(k) and P0(k-1) represents the power injected into the power grid by the energy storage battery pack at the kt moment and the (k-1) t moment respectively, and Pwp(k) The total output power of the wind power and the photovoltaic power generation at the kt moment;
then there is P0(k)-P0(k-1)=tPB(k) τ, the smoothing time constant τ therefore ranges from:
τ≥∣tPB(k)/ΔPB∣。
setting the capacity of the energy storage battery pack to be EBThen, there are:
EB(k)=[τtPwp(k)+τEB(k-1)]/(τ+t)，EB(k) and EBAnd (k-1) represents the electric quantity of the energy storage battery pack at the kt moment and the (k-1) t moment respectively.
Setting SOChighFor maximum state of charge, SOC, of the safe operating zone of the energy storage battery packlowFor minimum state of charge, SOC, of safe working area of energy storage battery packmaxIs the critical value of the higher region of the SOC of the energy storage battery pack, SOCminThe time constant of the basic low-pass filtering smoothing control strategy is tau for the critical value of the SOC overcharge region of the energy storage battery pack0，τcTime constant, τ, for charging energy storage battery packfTime constant, k, for discharging an energy storage battery1、k2、k3Respectively representing the change rate of the smoothing time constant in different intervals, the following are provided:
s1, current SOCmaxWhen the SOC (k) is less than or equal to 100 percent, the working SOC of the energy storage battery pack enters an overcharge region, which is a one-way working region, the energy storage battery pack is forbidden to be charged, and only the energy storage battery pack is allowed to be discharged, and the method comprises the following steps:
s1-1, when PBLet the smoothing time constant tau be less than 0c=0, preventing overcharge of the energy storage battery pack;
s1-2, when PBWhen > 0, let the smoothing time constant tauf=k1[SOC(t)-SOCmax]+τ0Discharging the energy storage battery pack;
s2, current SOChigh≤SOC(k)＜SOCmaxDuring, for the higher interval of SOC, the energy storage group battery is less charged, and discharge more, then have:
s2-1, when PBLet the smoothing time constant tau be less than 0c=k2[SOC(t)-SOChigh]+τ0Limiting charging of the energy storage battery pack;
s2-2, when PBWhen > 0, let the smoothing time constant tauf=k3[SOC(t)-SOChigh]+τ0The energy storage battery pack discharges more;
s3, current SOClow＜SOC(k)＜SOChighThen, for the SOC safe working area, the smooth control strategy is processed according to the low-pass filtering control strategy of the timing constant, and let tauc=τf=τ0The output of the energy storage battery pack is reduced;
s4, current SOCmin＜SOC(k)≤SOClowIn time, in the lower SOC interval, store energyThe battery pack is charged more and discharged less, so that the following steps are provided:
s4-1, when PBLet the smoothing time constant tau be less than 0c=k3[SOClow-SOC(t)]+τ0Charging the energy storage battery pack more;
s4-2, when PBWhen > 0, let the smoothing time constant tauf=k2[SOClow-SOC(t)]+τ0Limiting discharge of the energy storage battery pack;
s5, when 0% < SOC (k) ≦ SOCminDuring the time, get into SOC and cross the interval of putting, for one-way workspace, forbid the energy storage group battery and discharge, only allow its to charge, then have:
s5-1, when PBLet the smoothing time constant tau be less than 0c=k1[SOCmin-SOC(t)]+τ0Charging the energy storage battery pack more;
s5-2, when PBWhen > 0, let the smoothing time constant taufAnd =0, preventing the energy storage battery pack from over-discharging.
The SOC active regulator adopts a fuzzy control algorithm and corrects the output P of the energy storage batteryB-refAnd active regulation control of the energy storage battery pack when the SOC is too high or too low is realized.
The control strategy provided by the invention fully considers the SOC of the energy storage battery, avoids the overcharge and the overdischarge of the battery, and also designs the SOC active regulator by utilizing a fuzzy control algorithm, so that the SOC of the energy storage battery can be quickly recovered to a reasonable range when in an extreme state, and the service life of the energy storage battery is prolonged.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalents and substitutions made within the scope of the present invention should be included.
Claims (6)
1. An integrated energy system of an energy hub, characterized by: the system comprises a power generation unit, an energy storage battery pack and a control unit, wherein the energy storage battery pack is arranged at an outlet of the power generation unit, the power generation unit is connected to a bus through a feeder line, the power generation unit comprises a wind-electricity and light-electricity complementary power supply system consisting of a photovoltaic array and a wind generating set, and the control unit switches and adjusts the working state of the energy storage battery pack, protects the overshoot and the over-discharge of the energy storage battery pack and tracks the power of the power generation unit;
the controller of the control unit adopts an energy storage smoothing control strategy, controls the charge state of the energy storage battery pack by a variable time constant on the basis of a low-pass filtering smoothing control strategy, introduces fuzzy control and improves the automatic adjustment capability of the SOC.
2. An integrated energy system of an energy hub according to claim 1, characterized in that: the output end of the wind generating set is provided with an unloading circuit which is used as a protection circuit of the wind generating set.
3. An integrated energy system of an energy hub according to claim 1, characterized in that: the energy storage battery pack is a hybrid energy storage battery pack consisting of a first layer of energy storage pack and a second layer of energy storage pack, wherein the first layer of energy storage pack is used for smoothing power components with rapid fluctuation, and the second layer of energy storage pack is used for smoothing power components with slower fluctuation speed.
4. An integrated energy system of an energy hub according to claim 1, characterized in that: the controller of the control unit comprises a voltage detection circuit module and a current detection circuit module, electric energy generated by the wind generating set is rectified by three phases to output direct current as one path of a double input circuit, and the photovoltaic array generates electricity as the other path of the double input circuit and becomes stable direct current to supply to an energy storage battery pack and a load through a double input Boost circuit.
5. An integrated energy system of an energy hub according to claim 1, characterized in that: the electric energy generated by the wind generating set is converted into the electric energy for charging the energy storage battery pack under the control of a singlechip of the controller through an alternating current-direct current conversion circuit in the wind power generating circuit and is supplied to a load;
the electric energy generated by the photovoltaic array is converted into the electric energy for charging the energy storage battery pack under the control of the singlechip of the controller through the direct current voltage stabilizer circuit in the light energy power generation circuit, and the electric energy is supplied to a load.
6. An integrated energy system of an energy hub according to claim 1, characterized in that: and when the controller of the control unit detects that the voltage of the access point of the power generation unit is lower than the lowest voltage allowed by the access point, the control unit enters an island operation mode.
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