CN108879743B - Hybrid energy storage power distribution method and system - Google Patents

Hybrid energy storage power distribution method and system Download PDF

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Publication number
CN108879743B
CN108879743B CN201810800204.1A CN201810800204A CN108879743B CN 108879743 B CN108879743 B CN 108879743B CN 201810800204 A CN201810800204 A CN 201810800204A CN 108879743 B CN108879743 B CN 108879743B
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power
energy storage
frequency power
type energy
frequency
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CN108879743A (en
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李学斌
张燚
陈海波
刘剑
陈世龙
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China Energy Engineering Group Tianjin Electric Power Design Institute Co ltd
Tianjin Jindian Power Supply Design Co ltd
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China Energy Engineering Group Tianjin Electric Power Design Institute Co ltd
Tianjin Jindian Power Supply Design Co ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28Arrangements for balancing of the load in a network by storage of energy

Abstract

The invention provides a hybrid energy storage power distribution method and a system, which relate to the technical field of power control and comprise the following steps: filtering low-frequency power components in power to be compensated of the power type energy storage device by adopting a second-order filtering method to obtain a corresponding high-frequency power instruction; obtaining a low-frequency power instruction of the energy type energy storage device according to the compensation power instruction and the high-frequency power instruction of the energy type energy storage device; and providing a high-frequency power instruction through the power type energy storage device, controlling the energy storage state according to the high-frequency power instruction, and simultaneously providing a low-frequency power instruction through the energy type energy storage device. According to the invention, the high-frequency power instruction is distributed to the power type energy storage device by constructing second-order filtering, and the low-frequency power instruction is distributed to the energy type energy storage device, so that the service life of the energy type energy storage device and the optimal charge state of the power type energy storage device are prolonged, the control strategy of an energy storage system is simplified, the capacity selection of the power type energy storage device is reduced, and the cost is saved.

Description

Hybrid energy storage power distribution method and system
Technical Field
The invention relates to the technical field of power control, in particular to a hybrid energy storage power distribution method and system.
Background
Due to different energy storage principles, energy storage devices such as lithium batteries and the like have high energy density, short cycle service life and poor capability of bearing high-power discharge, while power storage devices such as super capacitors and the like have high power density, long cycle service life and low energy density and can bear high-power discharge. In view of the above, some researchers have proposed a hybrid system of lithium batteries and super capacitors to make the energy storage system have high energy density and high power density and improve the performance of the energy storage system.
In a hybrid energy storage system, real-time power distribution of an energy type energy storage device and a power type energy storage device is a problem to be solved firstly in the hybrid energy storage system. In specific applications, the power command borne by the hybrid energy storage system can be determined according to requirements, such as compensating high-frequency components in the smooth wind power output or maintaining system power balance when the main power supply is made in an independent micro-grid. At present, among a plurality of methods for distributing power in a hybrid energy storage system, a distribution method based on power fluctuation property better conforms to the technical characteristics of each energy storage device in the hybrid energy storage system.
However, in this method, at the handover frequency, the output signal of the conventional low-pass filtering stage may contain higher high-frequency signal components, and the output signal of the conventional high-pass filtering stage may contain higher low-frequency signal components. This low frequency signal component is given for super capacitor's power, and great low frequency power can cause super capacitor's overcharge or overdischarge, and its influence mainly divide into two aspects, and one is super capacitor's overcharge or overdischarge can reduce super capacitor and undertake the ability of high frequency power, and the second is super capacitor of selecting great capacity for avoiding because super capacitor's overcharge and overdischarge, and the cost is higher.
Disclosure of Invention
In view of the above, the present invention provides a hybrid energy storage power allocation method and system, in which a high-frequency power command is allocated to a power type energy storage device, and a low-frequency power command is allocated to an energy type energy storage device, so as to prolong the service life of the power type energy storage device and the optimal state of charge of the energy type energy storage device, simplify the control strategy of an energy storage system, reduce the capacity selection of the power type energy storage device, and save the cost.
In a first aspect, an embodiment of the present invention provides a hybrid energy storage power distribution method, where the method includes:
a filtering step: filtering low-frequency power components in power to be compensated of the power type energy storage device by adopting a second-order filtering method to obtain a corresponding high-frequency power instruction;
a calculation step: obtaining a low-frequency power instruction of the energy type energy storage device according to the compensation power of the energy type energy storage device and the high-frequency power instruction;
a distribution step: and providing the high-frequency power instruction through a power type energy storage device, controlling the energy storage state according to the high-frequency power instruction, and providing the low-frequency power instruction through an energy type energy storage device.
With reference to the first aspect, an embodiment of the present invention provides a first possible implementation manner of the first aspect, wherein in the filtering step, the compensation power of the power storage device is calculated according to the following formula:
wherein, Pins_SC(s) is the power to be compensated for by the power type energy storage device, PHESS(s) is a power command, Pins_LBAnd(s) is the power to be compensated of the energy storage device, s is a complex variable of a complex field, and T is a filtering time constant.
With reference to the first aspect, an embodiment of the present invention provides a second possible implementation manner of the first aspect, wherein the energy storage device should compensate power according to the following equation:
wherein, Pins_LB(s) is the power to be compensated for by the energy storage device, PHESS(s) is the power command, s is the complex variable of the complex field, and T is the filter time constant.
With reference to the first aspect, an embodiment of the present invention provides a third possible implementation manner of the first aspect, wherein in the filtering step, the high-frequency power command is calculated according to the following formula:
wherein, Pins_SC'(s) is the high frequency power command, Pins_SC(s) For which the power storage device should compensate for power, PHESS(s) is the power command, s is the complex variable, and T is the filter time constant.
With reference to the first aspect, an embodiment of the present invention provides a fourth possible implementation manner of the first aspect, wherein in the calculating step, the low-frequency power instruction is calculated according to the following formula:
wherein, Pins_LB'(s) is the low frequency power command, Pins_SC'(s) is the high frequency power command, PHESS(s) is the power command, s is the complex variable, and T is the filter time constant.
With reference to the first aspect, an embodiment of the present invention provides a fifth possible implementation manner of the first aspect, where the power type energy storage device includes a super capacitor, and the energy type energy storage device includes a lithium battery.
In a second aspect, an embodiment of the present invention further provides a hybrid energy storage power distribution system, where the system includes:
the filtering unit is used for filtering low-frequency power components in power to be compensated of the power type energy storage device by adopting a second-order filtering method to obtain a corresponding high-frequency power instruction;
the computing unit is used for obtaining a low-frequency power instruction of the energy type energy storage device according to the compensation power of the energy type energy storage device and the high-frequency power instruction;
and the distribution unit is used for providing the high-frequency power instruction through a power type energy storage device, controlling the energy storage state according to the high-frequency power instruction and simultaneously providing the low-frequency power instruction through an energy type energy storage device.
With reference to the second aspect, an embodiment of the present invention provides a first possible implementation manner of the second aspect, wherein, in the filtering unit, the high-frequency power command is calculated according to the following formula:
wherein, Pins_SC'(s) is the high frequency power command, Pins_SC(s) is the power to be compensated for by the power type energy storage device, PHESS(s) is the power command, s is the complex variable, and T is the filter time constant.
With reference to the second aspect, an embodiment of the present invention provides a second possible implementation manner of the second aspect, wherein in the calculating unit, the low-frequency power instruction is calculated according to the following formula:
wherein, Pins_LB'(s) is the low frequency power command, Pins_SC'(s) is the high frequency power command, PHESS(s) is the power command, s is the complex variable, and T is the filter time constant.
In combination with the second aspect, the present invention provides a third possible implementation manner of the second aspect, where the power type energy storage device includes a super capacitor, and the energy type energy storage device includes a lithium battery.
The embodiment of the invention has the following beneficial effects:
the invention provides a hybrid energy storage power distribution method and a system, comprising the following steps: filtering low-frequency power components in power to be compensated of the power type energy storage device by adopting a second-order filtering method to obtain a corresponding high-frequency power instruction; obtaining a low-frequency power instruction of the energy type energy storage device according to the compensation power instruction and the high-frequency power instruction of the energy type energy storage device; and providing a high-frequency power instruction through the power type energy storage device, controlling the energy storage state according to the high-frequency power instruction, and simultaneously providing a low-frequency power instruction through the energy type energy storage device. According to the invention, the high-frequency power instruction is distributed to the power type energy storage device by constructing second-order filtering, and the low-frequency power instruction is distributed to the energy type energy storage device, so that the service life of the energy type energy storage device and the optimal charge state of the power type energy storage device are prolonged, the control strategy of an energy storage system is simplified, the capacity selection of the power type energy storage device is reduced, and the cost is saved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart of a hybrid energy storage power distribution method according to an embodiment of the present invention;
fig. 2 is a bode diagram of a conventional low-pass filtering unit according to a first embodiment of the present invention;
fig. 3 is a bode diagram of a conventional high-pass filtering link according to a first embodiment of the present invention;
fig. 4 is a bode diagram of a new high-pass filtering link according to an embodiment of the present invention;
fig. 5 is a bode diagram of a new low-pass filtering stage according to an embodiment of the present invention;
fig. 6 is a circuit diagram of an RC filter network according to a second embodiment of the present invention;
fig. 7 is a state of charge curve diagram of a super capacitor according to a first-order filtering algorithm provided in the second embodiment of the present invention;
fig. 8 is a super capacitor availability curve diagram of the first-order filtering algorithm according to the second embodiment of the present invention;
fig. 9 is a state of charge curve diagram of a super capacitor based on a second-order filtering algorithm according to a second embodiment of the present invention;
fig. 10 is a diagram illustrating a second-order filtering algorithm-based availability curve of a super capacitor according to a second embodiment of the present invention;
fig. 11 is a schematic diagram of a hybrid energy storage power distribution system according to a third embodiment of the present invention.
Icon:
100-a filtering unit; 200-a computing unit; 300-allocation unit.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. 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.
In a hybrid energy storage system, real-time power distribution of an energy type energy storage device and a power type energy storage device is a problem to be solved firstly in the hybrid energy storage system. In a specific application, the power command borne by the hybrid energy storage system can be determined according to the requirement. At present, among a plurality of methods for distributing power in a hybrid energy storage system, a distribution method based on power fluctuation property better conforms to the technical characteristics of each energy storage device in the hybrid energy storage system. However, in this method, at the handover frequency, the output signal of the conventional low-pass filtering stage may contain higher high-frequency signal components, and the output signal of the conventional high-pass filtering stage may contain higher low-frequency signal components. This low frequency signal component is given for super capacitor's power, and great low frequency power can cause super capacitor's overcharge or overdischarge, and its influence mainly divide into two aspects, and one is super capacitor's overcharge or overdischarge can reduce super capacitor and undertake the ability of high frequency power, and the second is super capacitor of selecting great capacity for avoiding because super capacitor's overcharge and overdischarge, and the cost is higher.
Based on this, according to the hybrid energy storage power distribution method and system provided by the embodiment of the invention, the high-frequency power instruction is distributed to the power type energy storage device, and the low-frequency power instruction is distributed to the energy type energy storage device, so that the service life of the energy type energy storage device and the optimal charge state of the power type energy storage device can be prolonged, the control strategy of the energy storage system is simplified, the capacity selection of the power type energy storage device is reduced, and the cost is saved.
For the convenience of understanding the embodiment, the hybrid energy storage power distribution method disclosed in the embodiment of the present invention will be described in detail first.
The first embodiment is as follows:
fig. 1 is a flowchart of a hybrid energy storage power distribution method according to an embodiment of the present invention.
The traditional hybrid energy storage power distribution method adopts a first-order low-pass filtering method, wherein the power to be compensated of an energy type energy storage device (taking a lithium battery as an example) is shown in a formula (1), and the power to be compensated of a power type energy storage device (taking a super capacitor as an example) is shown in a formula (2):
wherein, Pins_LB(s) is the power to be compensated for, P, of the lithium batteryins_SC(s) is the power to be compensated for by the super capacitor, PHESS(s) is the power command, s is the complex variable of the complex field, and T is the filter time constant.
When the filter time constant T is 0.1s, the handover frequency ω is as shown in equation (3):
the bode plot of the conventional low-pass filter transfer function in equation (1) is shown in fig. 2. As can be seen from fig. 2, the output amplitude of the conventional low-pass filtering element is-3 dB at the handover frequency, i.e. at this frequency, the output amplitude is 0.707 times the input amplitude, and it can be seen that the output signal may contain higher high-frequency signal components near the handover frequency.
The bode plot of the conventional high-pass filter transfer function in equation (2) is shown in fig. 3. As can be seen from fig. 3, the output amplitude of the conventional high-pass filtering element is-3 dB at the crossover frequency, i.e. at this frequency, the output amplitude is 0.707 times the input amplitude, and it can be seen that the output signal may contain high low-frequency signal components near the crossover frequency.
Based on the above conventional power distribution method, the present embodiment provides a new hybrid energy storage power distribution method. Referring to fig. 1, the hybrid energy storage power distribution method mainly includes the following steps:
a filtering step S110: filtering low-frequency power components in power to be compensated of the power type energy storage device by adopting a second-order filtering method to obtain a corresponding high-frequency power instruction;
calculation step S120: obtaining a low-frequency power instruction of the energy type energy storage device according to the compensation power instruction and the high-frequency power instruction of the energy type energy storage device;
specifically, near the handover frequency, the high-frequency power command obtained by using the formula (2) contains a higher low-frequency power component, so that the low-frequency power component in the formula (2) is further filtered to obtain a formula (4), which is the high-frequency power command P of the super capacitorins_SC'(s) to obtain the corresponding low-frequency power instruction P of the lithium batteryins_LB'(s) is as shown in formula (5).
An assignment step S130: and providing a high-frequency power instruction through the power type energy storage device, controlling the energy storage state according to the high-frequency power instruction, and simultaneously providing a low-frequency power instruction through the energy type energy storage device.
Specifically, bode diagrams corresponding to the transfer functions of the formula (4) and the formula (5) are respectively shown in fig. 4 and 5. The crossover frequency of the bode graph shown in fig. 4 is still 10rad/s, and at the crossover frequency, the output amplitude of the new high-pass filtering link is-6 dB, that is, at the frequency, the output amplitude is 0.501 times of the input amplitude, and in addition, compared with the conventional high-frequency filtering link, the slope of the amplitude-frequency asymptote line of the low-frequency region is 2 times of that of the conventional high-frequency filtering link, so that the new high-pass filtering link has stronger capability of filtering low-frequency components and trafficability of high-frequency components under the condition that the crossover frequency is not changed, so that the super capacitor can avoid the overcharge or overdischarge of the super capacitor caused by the low-frequency power while bearing the high-frequency power, and the capability of the super capacitor to bear the high-frequency power is increased.
The cross-over frequency of the bode plot shown in fig. 5 has a small change compared to fig. 2, the passing performance around 10rad/s is slightly higher than that of the conventional low-pass filtering link, and the slope of the amplitude-frequency asymptote in the high-frequency region is substantially the same as that of fig. 2, so that the characteristics of the new low-frequency filtering link are substantially the same as those of the conventional method.
In addition, the transfer function shown in equation (4) has two differential elements, so the filtering method has an important property: regardless of power command PHESSHow(s) varies, high frequency power command Pins_SC'(s) the integral over time always goes to 0, and the complex variable s changing to 0 is related to the filter time constant T, i.e. the power type energy storage element always has the tendency to return to the original energy storage state while providing high frequency power, and the low frequency power can be regarded as being provided by the energy type energy storage element. Therefore, the hybrid energy storage power distribution method provided by the embodiment can enable the energy type energy storage element to meet the requirement of high-frequency power without adding other control strategies, and meanwhile, the energy type energy storage element cannot stay in the states of overcharge and overdischarge, so that the output requirement of the high-frequency power is met during the operation of the hybrid energy storage device.
Example two:
fig. 6 is a circuit diagram of an RC filter network according to a second embodiment of the present invention.
The embodiment specifically analyzes the hybrid energy storage power allocation method, particularly the allocation step S130, provided by the foregoing embodiment based on the RC filter network.
Will power instruction PHESS(s) high frequency Power Command P for super capacitorins_SC(s) as the respective voltage values of the RC filter network circuit, as shown in fig. 6.
In the initial state, UCPower command P equal to 0HESSAfter input, Pins_SC、UCAnd i (t) start to change, the formula (6) is given:
when the circuit is in steady state, UC0, i.e. the integral of the current is 0, UCThe time constant of attenuation 0 is T' ═ 2RC ═ 2T, and the power instruction of this part of frequency components does not belong to the high-frequency power range, and can be regarded as being provided by the lithium battery energy storage. Thus, it is possible to provideThis process is present throughout the operation of the hybrid energy storage system.
Further, since the high frequency power command P is consideredins_SCThe integral of(s) over time always goes to 0, so the harsher case, the unit stage power instruction P, is selectedHESSAnd(s) is 1/s as the power command of the hybrid energy storage system, and assuming that the initial condition is 0, the output power command of the super capacitor energy storage is formula (7) according to formula (4):
performing inverse Laplace transform on the formula (7) to obtain a super capacitor time domain power instruction, as shown in a formula (8):
integrating equation (8) for the time t in the interval (0, + ∞) is the energy that the super capacitor needs to provide in the step power command, as shown in equation (9):
it can be seen that, by adopting the hybrid energy storage power distribution provided by the above embodiment, while the super capacitor is enabled to store energy and output high-frequency power, there is an attenuation component irrelevant to the input power command and the filtering process, the attenuation is a trend that the super capacitor returns to its initial energy storage state, and the time constant of the attenuation component is 2T, and it can be regarded as the attenuation power component provided by the storage battery. Under the action of the attenuation component, the super capacitor tends to return to the initial energy storage state, so that the method can enable the super capacitor to always tend to the maximum high-frequency power output state under the condition of not increasing other control strategies, and the capacity of compensating high-frequency power is enhanced.
If the integral link acts on the formula (7) and then inverse laplace transform is performed, the time domain variation trend of the capacity demand of the super capacitor energy storage in response to the unit step power instruction can be obtained, as shown in the formula (10):
in order to analyze the variation trend of the energy storage capacity requirement of the super capacitor, P is setins_SC' (T) 0, to obtain T TfWhen T is T, it can be seen by combining equations (7) and (10)fCapacity E of super capacitor for energy storageSCReaches a maximum value, t>TfThe latter decreases monotonically and approaches 0. Thus, t can be adjusted>TfTime Pins_SC' (t) as the recovery power back to its initial state of charge. It is to be noted that this recovered power is present throughout the charging and discharging of the supercapacitor energy storage, here only denoted ESCChange when monotonously reducedTrends were studied for their power recovery characteristics.
To Pins_SC(t) derivation to give formula (11):
let dPins_SC' (T)/dt is 0, and T is 2TfIt can be known that the energy storage power of the super capacitor is T2TfTime reaches an extreme value, t>2TfMonotonically increases (or decreases) to 0 while taking into account t>2TfIn time, has a formula (12)
Thus, t>2TfWhen the energy storage and recovery power of the super capacitor tends to 0, the speed is slower than that of the super capacitorTherefore, compared with the high-frequency power borne by the super capacitor energy storage, the recovery power is low-frequency power, and the low-frequency recovery power is borne by the lithium battery energy storage in the hybrid energy storage system. Because the capacity of the super capacitor for storing energy is smaller, the low-frequency recovery power can not influence the available capacity and the operation of the lithium battery for storing energy, and simultaneously, the super capacitor for storing energy can be ensured to tend to the optimal working state.
When a first-order filtering algorithm is adopted, the super capacitor mainly responds to a high-frequency component in a power instruction, but a relatively low-frequency power instruction near a cut-off frequency is also included, so that the charge state of the super capacitor is greatly fluctuated, as shown in fig. 7. Meanwhile, in the period of 14.48h to 14.54h, as the power requirement maintains a larger value within 3min, the capacity accumulation of the super capacitor is caused, the charge state of the super capacitor reaches the maximum limit, and the corresponding capacity availability of the super capacitor is also reduced to 0, as shown in fig. 8.
The simulation results are shown in fig. 9 and 10 by using the second-order filtering power distribution method. In fig. 9, the state of charge of the super capacitor is well controlled, and is substantially maintained within 30% -70% in response time, and simultaneously, the capacity accumulation effect is eliminated in a period of 14.48 h-14.54 h, and the super capacitor gradually returns to the initial state of charge after reaching a peak value. As can be seen from FIG. 10, the availability of the super capacitor maintains a high level during the response period, which is not lower than 0.6 during the 14.48h to 14.54h period, and a faster recovery is obtained.
Example three:
fig. 11 is a schematic diagram of a hybrid energy storage power distribution system according to a third embodiment of the present invention.
The embodiment provides a hybrid energy storage power distribution system, which is used for implementing the hybrid energy storage power distribution method in the embodiment. Referring to fig. 11, the hybrid energy storage power distribution system mainly includes the following units:
the filtering unit 100 is configured to filter a low-frequency power component in power to be compensated of the power storage device by using a second-order filtering method, so as to obtain a corresponding high-frequency power instruction;
specifically, the high-frequency power command is calculated according to the formula (4) in the above embodiment.
The calculation unit 200 is configured to obtain a low-frequency power instruction of the energy storage device according to the power and high-frequency power instruction to be compensated of the energy storage device;
specifically, the low frequency power command is calculated according to equation (5) in the above embodiment.
The distribution unit 300 is configured to provide a high-frequency power instruction through the power type energy storage device, control the energy storage state according to the high-frequency power instruction, and provide a low-frequency power instruction through the energy type energy storage device.
Further, the power type energy storage device includes but is not limited to a super capacitor, and the energy type energy storage device includes but is not limited to a lithium battery.
The system provided by the embodiment of the present invention has the same implementation principle and technical effect as the foregoing method embodiment, and for the sake of brief description, no mention is made in the system embodiment, and reference may be made to the corresponding contents in the foregoing method embodiment.
The hybrid energy storage power distribution method and system provided by the above embodiments are applicable to, but not limited to, the following ranges: the method comprises the following steps of power distribution of an energy type energy storage device and a power type energy storage device in the hybrid energy storage system, wind power output in a smooth wind power plant and power distribution of the energy storage system, power distribution of a distributed power source and the energy storage system in an independent micro-grid, and required capacity calculation of the power type energy storage device in the hybrid energy storage system.
According to the hybrid energy storage power distribution method and system, high-frequency power is borne by the power type energy storage device, so that the service life of the energy type energy storage device is prolonged; under the condition of not increasing an additional control strategy, the power type energy storage is in the optimal state of charge, and the control strategy of the energy storage system is simplified; due to the compensation and integration characteristics of the low-frequency power, the capacity selection of the power type energy storage device is reduced, and the cost is saved.
The embodiment of the invention has the following beneficial effects:
the invention provides a hybrid energy storage power distribution method and a system, comprising the following steps: filtering low-frequency power components in power to be compensated of the power type energy storage device by adopting a second-order filtering method to obtain a corresponding high-frequency power instruction; obtaining a low-frequency power instruction of the energy type energy storage device according to the compensation power instruction and the high-frequency power instruction of the energy type energy storage device; and providing a high-frequency power instruction through the power type energy storage device, controlling the energy storage state according to the high-frequency power instruction, and simultaneously providing a low-frequency power instruction through the energy type energy storage device. According to the invention, the high-frequency power instruction is distributed to the power type energy storage device by constructing second-order filtering, and the low-frequency power instruction is distributed to the energy type energy storage device, so that the service life of the energy type energy storage device and the optimal charge state of the power type energy storage device are prolonged, the control strategy of an energy storage system is simplified, the capacity selection of the power type energy storage device is reduced, and the cost is saved.
The embodiment of the present invention further provides an electronic device, which includes a memory and a processor, where the memory stores a computer program that can be run on the processor, and the processor implements the steps of the hybrid energy storage power allocation method provided in the foregoing embodiment when executing the computer program.
The embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the hybrid energy storage power allocation method of the foregoing embodiment are performed.
In the description of the present invention, it should be noted that the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one logical division, and there may be other divisions when actually implemented, and for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (4)

1. A hybrid energy storage power distribution method, the method comprising:
a filtering step: filtering low-frequency power components in power to be compensated of the power type energy storage device by adopting a second-order filtering method to obtain a corresponding high-frequency power instruction;
a calculation step: obtaining a low-frequency power instruction of the energy type energy storage device according to the compensation power of the energy type energy storage device and the high-frequency power instruction;
a distribution step: providing the high-frequency power instruction through a power type energy storage device, controlling an energy storage state according to the high-frequency power instruction, and simultaneously providing the low-frequency power instruction through an energy type energy storage device;
in the filtering step, the high frequency power command is calculated according to the following formula:
wherein, Pins_SC'(s) is the high frequency power command, Pins_SC(s) is the power to be compensated for by the power type energy storage device, PHESS(s) is a power command, s is a complex variable, and T is a filtering time constant;
in the calculating step, the low frequency power command is calculated according to the following equation:
wherein, Pins_LB'(s) is the low frequency power command, Pins_SC'(s) is the high frequency power command, PHESS(s) is a power command, s is a complex variable, and T is a filtering time constant;
in the filtering step, the compensation power of the power type energy storage device is calculated according to the following formula:
wherein, Pins_SC(s) is the power to be compensated for by the power type energy storage device, PHESS(s) is a power command, Pins_LB(s) is that the energy storage device should compensate for power,s is a complex variable of the complex field, and T is a filtering time constant;
the compensation power of the energy type energy storage device is calculated according to the following formula:
wherein, Pins_LB(s) is the power to be compensated for by the energy storage device, PHESS(s) is the power command, s is the complex variable of the complex field, and T is the filter time constant.
2. The method of claim 1, wherein the power type energy storage device comprises a super capacitor and the energy type energy storage device comprises a lithium battery.
3. A hybrid energy storage power distribution system, the system comprising:
the filtering unit is used for filtering low-frequency power components in power to be compensated of the power type energy storage device by adopting a second-order filtering method to obtain a corresponding high-frequency power instruction;
the computing unit is used for obtaining a low-frequency power instruction of the energy type energy storage device according to the compensation power of the energy type energy storage device and the high-frequency power instruction;
the distribution unit is used for providing the high-frequency power instruction through a power type energy storage device, controlling the energy storage state according to the high-frequency power instruction and simultaneously providing the low-frequency power instruction through the energy type energy storage device;
in the filtering unit, the high frequency power command is calculated according to the following formula:
wherein, Pins_SC'(s) is the high frequency power command, Pins_SC(s) is that the power type energy storage device should compensatePower, PHESS(s) is a power command, s is a complex variable, and T is a filtering time constant;
in the calculating unit, the low frequency power command is calculated according to the following equation:
wherein, Pins_LB'(s) is the low frequency power command, Pins_SC'(s) is the high frequency power command, PHESS(s) is a power command, s is a complex variable, and T is a filtering time constant;
in the filtering unit, the compensation power of the power type energy storage device is calculated according to the following formula:
wherein, Pins_SC(s) is the power to be compensated for by the power type energy storage device, PHESS(s) is a power command, Pins_LB(s) is the power to be compensated of the energy storage device, s is a complex variable of a complex field, and T is a filtering time constant;
the compensation power of the energy type energy storage device is calculated according to the following formula:
wherein, Pins_LB(s) is the power to be compensated for by the energy storage device, PHESS(s) is the power command, s is the complex variable of the complex field, and T is the filter time constant.
4. The system of claim 3, wherein the power storage device comprises a super capacitor and the energy storage device comprises a lithium battery.
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