CN111900712A - Direct-current micro-grid energy balance control method and system based on hybrid energy storage - Google Patents
Direct-current micro-grid energy balance control method and system based on hybrid energy storage Download PDFInfo
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- CN111900712A CN111900712A CN202010898475.2A CN202010898475A CN111900712A CN 111900712 A CN111900712 A CN 111900712A CN 202010898475 A CN202010898475 A CN 202010898475A CN 111900712 A CN111900712 A CN 111900712A
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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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/10—Parallel operation of dc sources
- H02J1/12—Parallel operation of dc generators with converters, e.g. with mercury-arc rectifier
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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
- 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
Abstract
The invention relates to a direct-current micro-grid energy balance control method and system based on hybrid energy storage. Determining a balance relation between the power of each module of a direct current micro-grid energy flow structure model and the power of a direct current bus; determining the balance power of the hybrid energy storage module according to the balance relation; HHT decomposition is carried out on the balanced power, and a power distribution result is determined; carrying out SOC estimation on the super capacitor and the storage battery to determine an estimation result; adjusting the power distribution result according to the estimation result and the overcharge and overdischarge protection rule, and determining the adjusted power distribution result; and inputting the adjusted power distribution result into a bidirectional Buck/Boost converter to realize the balance control of the output power of the storage battery and the super capacitor. The invention can give full play to the advantages of the hybrid energy storage equipment, reduce the use cost of the hybrid energy storage equipment, prevent the hybrid energy storage equipment from being overcharged and overdischarged and realize the energy balance of the direct-current micro-grid on the premise of safety and high efficiency.
Description
Technical Field
The invention relates to the field of direct-current power transmission of a power system, in particular to a direct-current micro-grid energy balance control method and system based on hybrid energy storage.
Background
At present, with the gradual development of renewable energy utilization, how to mine the value and benefit of distributed energy and apply the value and benefit becomes a research hotspot direction. The concept of a microgrid has been proposed, which has the advantage of being able to operate both on-grid and off-grid independently. The direct-current micro-grid is widely applied to a low-voltage distribution network due to the fact that the number of electric energy conversion links is small, the electric energy quality is high, and the energy control is convenient. Because new energy such as wind energy, solar energy and the like has strong volatility and intermittence, when the direct-current micro-grid is separated from the large power grid, the micro-grid is difficult to maintain stable bus voltage, and therefore an energy storage device can be added to realize energy balance of the micro-grid so as to maintain stable bus voltage. The hybrid energy storage equipment comprises two energy storage devices, namely a super capacitor and a storage battery, the super capacitor is high in response frequency, high in power density, low in response frequency of the storage battery and high in energy density, and the combination of the super capacitor and the storage battery can comprehensively meet the requirements of a micro-grid on the energy storage devices. The energy storage device releases or absorbs power to realize micro-grid energy balance. At present, in order to realize the efficient operation of the hybrid energy storage device, power needing to be balanced is mainly decomposed into two power signals, namely a high-frequency power signal and a low-frequency power signal, wherein the high-frequency power is borne by a super capacitor, and the low-frequency power signal is borne by a storage battery. And the power control method is realized by the respective power converters. The control method can fully exert the advantages of the storage battery and the super capacitor, and some demonstration projects are applied at present.
In the existing control method, a first-order filter adopts a constant time coefficient to decompose a power signal, only the characteristics of a microgrid and energy storage equipment are considered, and the SOC (state of charge) of a storage battery or a super capacitor is not considered. This is an important parameter for measuring the working state of the energy storage device, and the energy storage device cannot work normally within a certain range. Therefore, the hybrid energy storage device is caused to work in an abnormal SOC working area by the control method, and the service life of the energy storage device is greatly reduced. Further, the energy storage device may be in an overcharge and overdischarge working state, and the use safety of the energy storage device is reduced.
Disclosure of Invention
The invention aims to provide a method and a system for controlling energy balance of a direct-current micro-grid based on hybrid energy storage, and the method and the system are used for solving the problems that energy storage equipment is overcharged and overdischarged due to the fact that hybrid energy storage SOC is not considered when micro-grid energy balance control is carried out, the service life is greatly reduced, the use safety cannot be guaranteed and the like.
In order to achieve the purpose, the invention provides the following scheme:
a direct-current micro-grid energy balance control method based on hybrid energy storage comprises the following steps:
establishing a direct-current micro-grid energy flow structure model; the direct-current micro-grid energy flow structure model comprises a current load module, a hybrid energy storage module and a new energy power generation equipment module; the output ends of the current load module, the hybrid energy storage module and the new energy power generation equipment module are all connected in parallel on a direct current bus, and the terminal of the direct current bus is connected with a public power grid through a grid-side exchanger; the hybrid energy storage module comprises a storage battery and a super capacitor;
determining a balance relation between the power of each module of the direct-current microgrid energy flow structure model and the power of the direct-current bus according to the direct-current microgrid energy flow structure model;
determining the balance power of the hybrid energy storage module according to the balance relation;
performing Hilbert-yellow HHT decomposition on the balance power of the hybrid energy storage module to determine a power distribution result; the power distribution result comprises distributed reference power of the storage battery and distributed reference power of the super capacitor;
carrying out state of charge (SOC) estimation on the super capacitor and the storage battery, and determining an estimation result;
adjusting the power distribution result according to the estimation result and an overcharge and overdischarge protection rule, and determining the adjusted power distribution result;
inputting the adjusted power distribution result into a bidirectional Buck/Boost converter, and returning to the step of determining the balanced power of the hybrid energy storage module according to the balance relation until the balance control of the output power of the storage battery and the super capacitor is realized; the bidirectional Buck/Boost converter is used for power bidirectional flow control of charging and discharging of the storage battery and the super capacitor.
Optionally, the hilbert-yellow HHT decomposition is performed on the balanced power of the hybrid energy storage module, and a power allocation result is determined, which specifically includes:
performing empirical mode decomposition on the balance power of the hybrid energy storage module as a time domain quantity to obtain the balance power after the empirical mode decomposition;
hilbert transformation is carried out on the balance power after the empirical mode decomposition to obtain balance power after Hilbert transformation;
determining a complex frequency domain analytic signal according to the balance power after the empirical mode decomposition and the balance power after the Hilbert transformation;
determining an instantaneous frequency according to the complex frequency domain analytic signal;
performing least square fitting on the instantaneous frequency to determine an initial value of a filtering time constant of a first-order filter;
determining a first-order filter according to the initial value of the filtering time constant of the first-order filter;
determining the power allocation result using the first order filter.
Optionally, the estimating the state of charge SOC of the super capacitor and the storage battery, and determining the estimation result specifically includes:
and performing SOC estimation on the super capacitor and the storage battery by adopting an EKF mode to determine an estimation result.
Optionally, the adjusting the power distribution result according to the estimation result and the overcharge and overdischarge protection rule to determine the adjusted power distribution result specifically includes:
carrying out SOC partition on the super capacitor and the storage battery to obtain a partition schematic diagram;
comparing the estimation result with the partition diagram to obtain a comparison result;
performing first adjustment on the power distribution result according to the comparison result;
and performing secondary adjustment on the power distribution result after the primary adjustment according to the overcharge and overdischarge protection rule to obtain an adjusted power distribution result.
A direct current microgrid energy balance control system based on mixed energy storage comprises:
the direct-current micro-grid energy flow structure model building module is used for building a direct-current micro-grid energy flow structure model; the direct-current micro-grid energy flow structure model comprises a current load module, a hybrid energy storage module and a new energy power generation equipment module; the output ends of the current load module, the hybrid energy storage module and the new energy power generation equipment module are all connected in parallel on a direct current bus, and the terminal of the direct current bus is connected with a public power grid through a grid-side exchanger; the hybrid energy storage module comprises a storage battery and a super capacitor;
the balance relation determining module is used for determining the balance relation between the power of each module of the direct current microgrid energy flow structure model and the power of the direct current bus according to the direct current microgrid energy flow structure model;
the balance power determining module is used for determining the balance power of the hybrid energy storage module according to the balance relation;
the power distribution result determining module is used for performing Hilbert-yellow HHT decomposition on the balance power of the hybrid energy storage module and determining a power distribution result; the power distribution result comprises distributed reference power of the storage battery and distributed reference power of the super capacitor;
the estimation result determining module is used for estimating the state of charge (SOC) of the super capacitor and the storage battery and determining an estimation result;
the adjusted power distribution result determining module is used for adjusting the power distribution result according to the estimation result and the overcharge and overdischarge protection rule and determining the adjusted power distribution result;
the balance control module is used for inputting the adjusted power distribution result into a bidirectional Buck/Boost converter and returning to the step of determining the balanced power of the hybrid energy storage module according to the balance relation until the balance control of the output power of the storage battery and the output power of the super capacitor is realized; the bidirectional Buck/Boost converter is used for power bidirectional flow control of charging and discharging of the storage battery and the super capacitor.
Optionally, the power allocation result determining module specifically includes:
the balance power determination unit after empirical mode decomposition is used for performing empirical mode decomposition on the balance power of the hybrid energy storage module as a time domain quantity to obtain the balance power after empirical mode decomposition;
the balance power determination unit after Hilbert transform is used for performing Hilbert transform on the balance power after empirical mode decomposition to obtain the balance power after Hilbert transform;
the complex frequency domain analytic signal determining unit is used for determining a complex frequency domain analytic signal according to the balance power after the empirical mode decomposition and the balance power after the Hilbert transformation;
an instantaneous frequency determining unit, configured to determine an instantaneous frequency according to the complex frequency domain analytic signal;
the first-order filter filtering time constant initial value determining unit is used for performing least square fitting on the instantaneous frequency to determine a first-order filter filtering time constant initial value;
the first-order filter determining unit is used for determining a first-order filter according to the initial value of the filtering time constant of the first-order filter;
a power allocation result determining unit for determining the power allocation result using the first order filter.
Optionally, the estimation result determining module specifically includes:
and the estimation result determining unit is used for estimating the SOC of the super capacitor and the storage battery by adopting an extended Kalman filter EKF mode and determining an estimation result.
Optionally, the adjusted power allocation result determining module specifically includes:
the partition schematic diagram determining unit is used for carrying out SOC partition on the super capacitor and the storage battery to obtain a partition schematic diagram;
the comparison result determining unit is used for comparing the estimation result with the partition schematic diagram to obtain a comparison result;
a power distribution result first adjustment unit, configured to perform first adjustment on the power distribution result according to the comparison result;
and the power distribution result secondary adjustment unit is used for carrying out secondary adjustment on the power distribution result after the primary adjustment according to the overcharge and overdischarge protection rule to obtain an adjusted power distribution result.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
according to the direct-current micro-grid energy balance control method and system based on hybrid energy storage, the balance relation between the power of each module of the direct-current micro-grid energy flow structure model and the power of the direct-current bus is determined according to the direct-current micro-grid energy flow structure model, and the balance power of the hybrid energy storage module is determined according to the balance relation; performing Hilbert-Huang HHT decomposition on the balance power of the hybrid energy storage module, determining a power distribution result, performing SOC estimation on the super capacitor and the storage battery, and determining an estimation result; adjusting the power distribution result according to the estimation result and an overcharge and overdischarge protection rule, and determining the adjusted power distribution result; and applying the adjusted power distribution result to a power converter of the hybrid energy storage equipment to realize balance control. The problems that when the energy balance control of the micro-grid is carried out, the energy storage equipment is overcharged and over-discharged due to the fact that the hybrid energy storage SOC is not considered, the service life is greatly reduced, and the use safety cannot be guaranteed are solved. The advantages of the hybrid energy storage device can be fully exerted, the use cost of the hybrid energy storage device is reduced, the hybrid energy storage device is prevented from being overcharged and over-discharged, and the energy balance of the direct-current micro-grid is realized on the premise of safety and high efficiency.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
Fig. 1 is a schematic flow chart of a hybrid energy storage based direct-current microgrid energy balance control method provided by the invention;
fig. 2 is a schematic structural diagram of a dc microgrid energy flow structural model provided by the present invention;
fig. 3 is a schematic diagram of the hybrid energy storage based dc microgrid energy balance control logic provided in the present invention;
FIG. 4 is a schematic diagram of a storage battery and a super capacitor SOC partition provided by the invention;
FIG. 5 is a schematic diagram of the control logic of the bidirectional Buck/Boost converter provided;
fig. 6 is a schematic structural diagram of a hybrid energy storage based direct-current microgrid energy balance control system provided by the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a method and a system for controlling energy balance of a direct-current micro-grid based on hybrid energy storage, and the method and the system are used for solving the problems that energy storage equipment is overcharged and overdischarged due to the fact that hybrid energy storage SOC is not considered when micro-grid energy balance control is carried out, the service life is greatly reduced, the use safety cannot be guaranteed and the like.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Fig. 1 is a schematic flow chart of a method for controlling energy balance of a dc microgrid based on hybrid energy storage provided by the present invention, fig. 3 is a schematic logic diagram of controlling energy balance of a dc microgrid based on hybrid energy storage provided by the present invention, as shown in fig. 1 and fig. 3, the method for controlling energy balance of a dc microgrid based on hybrid energy storage provided by the present invention includes:
s101, establishing a direct-current microgrid energy flow structure model as shown in figure 2; the direct-current micro-grid energy flow structure model comprises a current load module, a hybrid energy storage module and a new energy power generation equipment module; the output ends of the current load module, the hybrid energy storage module and the new energy power generation equipment module are all connected in parallel on a direct current bus, and the terminal of the direct current bus is connected with a public power grid through a grid-side exchanger; the hybrid energy storage module comprises a storage battery and a super capacitor.
As a specific embodiment, the new energy power generation module adopts wind power generation equipment, which has better volatility and can better verify the advantages of the energy control method. The storage battery is a lithium battery, has large capacity, can be repeatedly charged and discharged, and can well verify the effect of the storage battery in the hybrid energy storage equipment.
And S102, determining a balance relation between the power of each module of the direct-current microgrid energy flow structure model and the power of the direct-current bus according to the direct-current microgrid energy flow structure model.
S103, determining the balance power of the hybrid energy storage module according to the balance relation. The DC load module, the hybrid energy storage module, the new energy power generation equipment module and the DC bus measure the power P of the DC load through the power detection deviceloadThe balance power of the hybrid energy storage module is PhessThe power of the new energy power generation module is PwAnd the power of the DC bus is PdcThe balance relation formula of the power of the direct-current micro-grid is as follows: pdc＝Pw+Phess-PloadGo forward and go forwardAnd the balance power P of the hybrid energy storage module can be calculatedhessBalanced power P of hybrid energy storage modulehessThe power P being borne by the accumulatorbBears power P with super capacitorcAnd (4) forming.
S104, balancing power P of the hybrid energy storage modulehessPerforming Hilbert-Huang HHT decomposition to determine a power distribution result; the power distribution result includes a distributed reference power P of the storage batteryb1And reference power P distributed by the super capacitorc1。
S104 specifically comprises the following steps:
and carrying out empirical mode decomposition on the balance power of the hybrid energy storage module as a time domain quantity to obtain the balance power after the empirical mode decomposition.
Firstly, the balance power P ishessAs a time domain quantity Phess(t)EMD was performed, the decomposition procedure was as follows:
wherein c isi(t) is the function of each natural mode after decomposition, and r is a function in which a natural mode cannot be obtained monotonously.
And Hilbert transform is carried out on the balance power after the empirical mode decomposition to obtain the balance power after the Hilbert transform. Namely, each inherent mode function in the balanced power after empirical mode decomposition is formulated
A Hilbert transform is performed.
And determining a complex frequency domain analytic signal according to the balance power after the empirical mode decomposition and the balance power after the Hilbert transformation. Namely using the formula
A complex frequency domain analytic signal is determined.
Determining an instantaneous frequency from the complex frequency domain analytic signal
And performing least square fitting on the instantaneous frequency to determine an initial value of a filtering time constant of a first-order filter.
And determining a first-order filter according to the initial value of the filtering time constant of the first-order filter.
Determining the power allocation result using the first order filter.
The specific process of determining the power allocation result by using the first-order filter is as follows:
s105, carrying out SOC estimation on the super capacitor and the storage battery, and determining an estimation result;
s105 specifically comprises the following steps:
and performing SOC estimation on the super capacitor and the storage battery by adopting an EKF mode to determine an estimation result.
And S106, adjusting the power distribution result according to the estimation result and the overcharge and overdischarge protection rule, and determining the adjusted power distribution result.
S106 specifically comprises:
and carrying out SOC partition on the super capacitor and the storage battery to obtain a partition schematic diagram, and the partition schematic diagram is shown in FIG. 4.
And comparing the estimation result with the partition diagram to obtain a comparison result.
And adjusting the power distribution result for the first time according to the comparison result.
Adjusting the initial value t of the first-order filter filtering time constantsIs ts+ Δ t, so as to change the required borne power of the super capacitor to Pc2, and the corresponding borne power of the storage battery to Pb2。
The specific adjusting process comprises the following steps:
1) when in the inhibited discharge region: the super capacitor is limited to discharge, when the hybrid energy storage module is charged, power is distributed to the super capacitor as much as possible, and delta t is adjusted according to the charge-discharge state of the super capacitor;
2) when in the discharge alert zone: the output principle of the super capacitor is that less discharge is carried out and more charge is carried out, the purpose is to delay the descending trend of the SOC of the super capacitor, and delta t is adjusted according to the charge-discharge state of the super capacitor;
3) when in normal work area: the output of the super capacitor and the storage battery is not adjusted, and delta t is 0;
4) when in the charging alert zone: the output principle of the super capacitor is that less charge is carried out and more discharge is carried out, the rising trend of the SOC of the super capacitor is delayed, and delta t is adjusted according to the charge-discharge state of the super capacitor;
5) when in the charge inhibition zone: the super capacitor is charged statically and can only discharge. Adjusting delta t according to the charge-discharge state of the super capacitor;
and performing secondary adjustment on the power distribution result after the primary adjustment according to the overcharge and overdischarge protection rule to obtain an adjusted power distribution result. Namely, the super capacitor borne power is adjusted to be P according to the overcharge and overdischarge protection rulec3Corresponding to the battery bearing power Pb3So as to avoid the overcharge and the overdischarge of the super capacitor. The overcharge and overdischarge protection method specifically comprises the following steps:
1) when in the discharge-inhibiting region:
super capacitor:
a storage battery:
2) when in the charge inhibited region:
super capacitor:
a storage battery:
wherein subscript c represents a super capacitor, subscript b represents a battery, SOCmax、SOCmin、SOChigh、SOClowCorresponding to the SOC partition boundary value.
S107, inputting the adjusted power distribution result into a bidirectional Buck/Boost converter, and returning to the step of determining the balanced power of the hybrid energy storage module according to the balance relation until the balance control of the output power of the storage battery and the output power of the super capacitor is realized; the bidirectional Buck/Boost converter is used for power bidirectional flow control of charging and discharging of the storage battery and the super capacitor, and control logic is shown in figure 5.
The method comprises the steps of firstly carrying out energy balance analysis on a direct current microgrid to obtain power required to be balanced by hybrid energy storage equipment, decomposing the power required to be balanced by using a HHT combined first-order filter, bearing high-frequency power by a super capacitor and low-frequency power by a storage battery, judging the working state of the energy storage equipment by comparing SOC partitions according to the estimation result of the hybrid energy storage SOC, accordingly carrying out corresponding power distribution adjustment, further adjusting the distributed power by using an overcharge and overdischarge protection rule on the basis of avoiding the overcharge and overdischarge of the hybrid energy storage equipment, and finally finishing input and output control on the hybrid energy storage power by a bidirectional Buck/Boost converter according to the distributed power, thereby realizing the energy balance of the direct current microgrid. The hybrid energy storage device performs energy control consideration by combining the state SOC of the hybrid energy storage device, and has high use efficiency and high use safety.
Fig. 6 is a schematic structural diagram of a dc microgrid energy balance control system based on hybrid energy storage provided by the present invention, and as shown in fig. 6, the dc microgrid energy balance control system based on hybrid energy storage provided by the present invention includes:
the direct-current microgrid energy flow structure model building module 601 is used for building a direct-current microgrid energy flow structure model; the direct-current micro-grid energy flow structure model comprises a current load module, a hybrid energy storage module and a new energy power generation equipment module; the output ends of the current load module, the hybrid energy storage module and the new energy power generation equipment module are all connected in parallel on a direct current bus, and the terminal of the direct current bus is connected with a public power grid through a grid-side exchanger; the hybrid energy storage module comprises a storage battery and a super capacitor.
The balance relationship determining module 602 is configured to determine, according to the dc microgrid energy flow structure model, a balance relationship between the power of each module of the dc microgrid energy flow structure model and the power of the dc bus.
The balance power determining module 603 is configured to determine the balance power of the hybrid energy storage module according to the balance relationship;
the power distribution result determining module 604 is configured to perform hilbert-yellow HHT decomposition on the balanced power of the hybrid energy storage module, and determine a power distribution result; the power distribution result comprises distributed reference power of the storage battery and distributed reference power of the super capacitor.
The estimation result determination module 605 is configured to perform state of charge SOC estimation on the super capacitor and the storage battery, and determine an estimation result.
The adjusted power distribution result determining module 606 is configured to adjust the power distribution result according to the estimation result and the overcharge-overdischarge protection rule, and determine an adjusted power distribution result.
The balance control module 607 is configured to input the adjusted power distribution result to a bidirectional Buck/Boost converter, and return to the step of determining the balanced power of the hybrid energy storage module according to the balance relationship until balance control over the output power of the storage battery and the super capacitor is achieved; the bidirectional Buck/Boost converter is used for power bidirectional flow control of charging and discharging of the storage battery and the super capacitor.
The power allocation result determining module 604 specifically includes:
and the balanced power determination unit after empirical mode decomposition is used for performing empirical mode decomposition on the balanced power of the hybrid energy storage module as a time domain quantity to obtain the balanced power after empirical mode decomposition.
And the balanced power determination unit after Hilbert transform is used for performing Hilbert transform on the balanced power after empirical mode decomposition to obtain the balanced power after Hilbert transform.
And the complex frequency domain analysis signal determining unit is used for determining a complex frequency domain analysis signal according to the balance power after the empirical mode decomposition and the balance power after the Hilbert transformation.
And the instantaneous frequency determining unit is used for determining the instantaneous frequency according to the complex frequency domain analytic signal.
And the first-order filter filtering time constant initial value determining unit is used for performing least square fitting on the instantaneous frequency to determine a first-order filter filtering time constant initial value.
And the first-order filter determining unit is used for determining a first-order filter according to the initial value of the filtering time constant of the first-order filter.
A power allocation result determining unit for determining the power allocation result using the first order filter.
The estimation result determining module 605 specifically includes:
and the estimation result determining unit is used for estimating the SOC of the super capacitor and the storage battery by adopting an extended Kalman filter EKF mode and determining an estimation result.
The adjusted power allocation result determining module 606 specifically includes:
and the partition schematic diagram determining unit is used for carrying out SOC partition on the super capacitor and the storage battery to obtain a partition schematic diagram.
And the comparison result determining unit is used for comparing the estimation result with the partition schematic diagram to obtain a comparison result.
And the power distribution result first-time adjusting unit is used for adjusting the power distribution result for the first time according to the comparison result.
And the power distribution result secondary adjustment unit is used for carrying out secondary adjustment on the power distribution result after the primary adjustment according to the overcharge and overdischarge protection rule to obtain an adjusted power distribution result.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (8)
1. A direct-current microgrid energy balance control method based on hybrid energy storage is characterized by comprising the following steps:
establishing a direct-current micro-grid energy flow structure model; the direct-current micro-grid energy flow structure model comprises a current load module, a hybrid energy storage module and a new energy power generation equipment module; the output ends of the current load module, the hybrid energy storage module and the new energy power generation equipment module are all connected in parallel on a direct current bus, and the terminal of the direct current bus is connected with a public power grid through a grid-side exchanger; the hybrid energy storage module comprises a storage battery and a super capacitor;
determining a balance relation between the power of each module of the direct-current microgrid energy flow structure model and the power of the direct-current bus according to the direct-current microgrid energy flow structure model;
determining the balance power of the hybrid energy storage module according to the balance relation;
performing Hilbert-yellow HHT decomposition on the balance power of the hybrid energy storage module to determine a power distribution result; the power distribution result comprises distributed reference power of the storage battery and distributed reference power of the super capacitor;
carrying out state of charge (SOC) estimation on the super capacitor and the storage battery, and determining an estimation result;
adjusting the power distribution result according to the estimation result and an overcharge and overdischarge protection rule, and determining the adjusted power distribution result;
inputting the adjusted power distribution result into a bidirectional Buck/Boost converter, and returning to the step of determining the balanced power of the hybrid energy storage module according to the balance relation until the balance control of the output power of the storage battery and the super capacitor is realized; the bidirectional Buck/Boost converter is used for power bidirectional flow control of charging and discharging of the storage battery and the super capacitor.
2. The method as claimed in claim 1, wherein the step of performing hilbert-yellow HHT decomposition on the balanced power of the hybrid energy storage module to determine the power distribution result specifically comprises:
performing empirical mode decomposition on the balance power of the hybrid energy storage module as a time domain quantity to obtain the balance power after the empirical mode decomposition;
hilbert transformation is carried out on the balance power after the empirical mode decomposition to obtain balance power after Hilbert transformation;
determining a complex frequency domain analytic signal according to the balance power after the empirical mode decomposition and the balance power after the Hilbert transformation;
determining an instantaneous frequency according to the complex frequency domain analytic signal;
performing least square fitting on the instantaneous frequency to determine an initial value of a filtering time constant of a first-order filter;
determining a first-order filter according to the initial value of the filtering time constant of the first-order filter;
determining the power allocation result using the first order filter.
3. The hybrid energy storage based direct current microgrid energy balance control method according to claim 1, characterized in that the estimation of the state of charge (SOC) of the super capacitor and the storage battery and the determination of the estimation result specifically comprise:
and performing SOC estimation on the super capacitor and the storage battery by adopting an EKF mode to determine an estimation result.
4. The method as claimed in claim 1, wherein the step of determining the adjusted power distribution result by adjusting the power distribution result according to the estimation result and the overcharge-overdischarge protection rule comprises:
carrying out SOC partition on the super capacitor and the storage battery to obtain a partition schematic diagram;
comparing the estimation result with the partition diagram to obtain a comparison result;
performing first adjustment on the power distribution result according to the comparison result;
and performing secondary adjustment on the power distribution result after the primary adjustment according to the overcharge and overdischarge protection rule to obtain an adjusted power distribution result.
5. The utility model provides a direct current microgrid energy balance control system based on mix energy storage which characterized in that includes:
the direct-current micro-grid energy flow structure model building module is used for building a direct-current micro-grid energy flow structure model; the direct-current micro-grid energy flow structure model comprises a current load module, a hybrid energy storage module and a new energy power generation equipment module; the output ends of the current load module, the hybrid energy storage module and the new energy power generation equipment module are all connected in parallel on a direct current bus, and the terminal of the direct current bus is connected with a public power grid through a grid-side exchanger; the hybrid energy storage module comprises a storage battery and a super capacitor;
the balance relation determining module is used for determining the balance relation between the power of each module of the direct current microgrid energy flow structure model and the power of the direct current bus according to the direct current microgrid energy flow structure model;
the balance power determining module is used for determining the balance power of the hybrid energy storage module according to the balance relation;
the power distribution result determining module is used for performing Hilbert-yellow HHT decomposition on the balance power of the hybrid energy storage module and determining a power distribution result; the power distribution result comprises distributed reference power of the storage battery and distributed reference power of the super capacitor;
the estimation result determining module is used for estimating the state of charge (SOC) of the super capacitor and the storage battery and determining an estimation result;
the adjusted power distribution result determining module is used for adjusting the power distribution result according to the estimation result and the overcharge and overdischarge protection rule and determining the adjusted power distribution result;
the balance control module is used for inputting the adjusted power distribution result into a bidirectional Buck/Boost converter and returning to the step of determining the balanced power of the hybrid energy storage module according to the balance relation until the balance control of the output power of the storage battery and the output power of the super capacitor is realized; the bidirectional Buck/Boost converter is used for power bidirectional flow control of charging and discharging of the storage battery and the super capacitor.
6. The system of claim 5, wherein the power distribution result determination module specifically comprises:
the balance power determination unit after empirical mode decomposition is used for performing empirical mode decomposition on the balance power of the hybrid energy storage module as a time domain quantity to obtain the balance power after empirical mode decomposition;
the balance power determination unit after Hilbert transform is used for performing Hilbert transform on the balance power after empirical mode decomposition to obtain the balance power after Hilbert transform;
the complex frequency domain analytic signal determining unit is used for determining a complex frequency domain analytic signal according to the balance power after the empirical mode decomposition and the balance power after the Hilbert transformation;
an instantaneous frequency determining unit, configured to determine an instantaneous frequency according to the complex frequency domain analytic signal;
the first-order filter filtering time constant initial value determining unit is used for performing least square fitting on the instantaneous frequency to determine a first-order filter filtering time constant initial value;
the first-order filter determining unit is used for determining a first-order filter according to the initial value of the filtering time constant of the first-order filter;
a power allocation result determining unit for determining the power allocation result using the first order filter.
7. The system according to claim 5, wherein the estimation result determining module specifically comprises:
and the estimation result determining unit is used for estimating the SOC of the super capacitor and the storage battery by adopting an extended Kalman filter EKF mode and determining an estimation result.
8. The system of claim 5, wherein the adjusted power distribution result determining module specifically comprises:
the partition schematic diagram determining unit is used for carrying out SOC partition on the super capacitor and the storage battery to obtain a partition schematic diagram;
the comparison result determining unit is used for comparing the estimation result with the partition schematic diagram to obtain a comparison result;
a power distribution result first adjustment unit, configured to perform first adjustment on the power distribution result according to the comparison result;
and the power distribution result secondary adjustment unit is used for carrying out secondary adjustment on the power distribution result after the primary adjustment according to the overcharge and overdischarge protection rule to obtain an adjusted power distribution result.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112865067A (en) * | 2021-01-14 | 2021-05-28 | 武汉工程大学 | Power distribution method and system of hybrid energy storage system and electronic equipment |
| CN115001122A (en) * | 2022-08-04 | 2022-09-02 | 深圳市今朝时代股份有限公司 | Super capacitor electric energy storage management system based on data analysis |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106998072A (en) * | 2017-05-15 | 2017-08-01 | 国网江苏省电力公司电力科学研究院 | A kind of mixed energy storage system capacity configuration optimizing method for optimizing operation towards power distribution network |
| CN107425531A (en) * | 2017-07-24 | 2017-12-01 | 武汉理工大学 | Renewable energy power generation output-power fluctuation smoothing method based on EMD |
| CN109088421A (en) * | 2018-08-28 | 2018-12-25 | 河海大学 | Mixed energy storage system capacity configuration optimizing method based on FDM |
| CN109103941A (en) * | 2018-10-26 | 2018-12-28 | 贵州电网有限责任公司 | It is a kind of that method is stabilized based on the fluctuation of the wind-powered electricity generation of HHT and filtering algorithm |
| CN110148958A (en) * | 2019-06-10 | 2019-08-20 | 南京工程学院 | A kind of mixed energy storage system control strategy based on the sagging control of SOC balance |
-
2020
- 2020-08-31 CN CN202010898475.2A patent/CN111900712A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106998072A (en) * | 2017-05-15 | 2017-08-01 | 国网江苏省电力公司电力科学研究院 | A kind of mixed energy storage system capacity configuration optimizing method for optimizing operation towards power distribution network |
| CN107425531A (en) * | 2017-07-24 | 2017-12-01 | 武汉理工大学 | Renewable energy power generation output-power fluctuation smoothing method based on EMD |
| CN109088421A (en) * | 2018-08-28 | 2018-12-25 | 河海大学 | Mixed energy storage system capacity configuration optimizing method based on FDM |
| CN109103941A (en) * | 2018-10-26 | 2018-12-28 | 贵州电网有限责任公司 | It is a kind of that method is stabilized based on the fluctuation of the wind-powered electricity generation of HHT and filtering algorithm |
| CN110148958A (en) * | 2019-06-10 | 2019-08-20 | 南京工程学院 | A kind of mixed energy storage system control strategy based on the sagging control of SOC balance |
Non-Patent Citations (2)
| Title |
|---|
| 徐玉涛等: "基于HHT与滤波算法的风电波动平抑策略研究", 《电气传动》 * |
| 王宇: "超级电容与蓄电池混合储能系统的能量管理与控制研究", 《中国优秀硕士学位论文全文数据库 工程科技II辑》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112865067A (en) * | 2021-01-14 | 2021-05-28 | 武汉工程大学 | Power distribution method and system of hybrid energy storage system and electronic equipment |
| CN112865067B (en) * | 2021-01-14 | 2022-11-01 | 武汉工程大学 | Power distribution method and system of hybrid energy storage system and electronic equipment |
| CN115001122A (en) * | 2022-08-04 | 2022-09-02 | 深圳市今朝时代股份有限公司 | Super capacitor electric energy storage management system based on data analysis |
| CN115001122B (en) * | 2022-08-04 | 2022-11-29 | 深圳市今朝时代股份有限公司 | Super capacitor electric energy storage management system based on data analysis |
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