CN111404185B - Charging system control method, controller and system - Google Patents
Charging system control method, controller and system Download PDFInfo
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- CN111404185B CN111404185B CN202010201243.7A CN202010201243A CN111404185B CN 111404185 B CN111404185 B CN 111404185B CN 202010201243 A CN202010201243 A CN 202010201243A CN 111404185 B CN111404185 B CN 111404185B
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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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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
- B60L53/60—Monitoring or controlling charging stations
- B60L53/64—Optimising energy costs, e.g. responding to electricity rates
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02T90/10—Technologies relating to charging of electric vehicles
- Y02T90/12—Electric charging stations
Abstract
The invention provides a control method, a controller and a system of a charging system, which are applied to the technical field of direct current charging. The control method of the charging system provided by the invention refers to the magnitude relation between the current electricity price of the power supply network and the preset discharging electricity price threshold value, controls the discharging process of the energy storage system, avoids the reduction of the benefit of the charging system due to the unreasonable selection of the discharging time, and effectively improves the economic benefit of the direct current charging system.
Description
Technical Field
The invention belongs to the technical field of direct current charging, and particularly relates to a charging system control method, a controller and a system.
Background
A direct current charging system is often provided with a plurality of direct current charging units, and the direct current charging units are used for rapidly charging the electric automobile. With the increase of the number of the direct current charging units, the output power of the direct current charging system is increased, but the power supply network connected with the direct current charging system is difficult to realize low-cost capacity upgrade, and in order to meet the actual use requirement, the loading capacity of the direct current charging system can be improved by increasing the energy storage system.
Referring to fig. 1, fig. 1 is a schematic diagram of a system architecture of a DC charging system in the prior art, in which a centralized rectifier AC/DC is used to perform uniform rectification and conversion on AC power output by a power supply transformer, and the DC power is output to each charging unit connected to a DC bus through the DC bus, and finally each charging unit charges a vehicle to be charged. The direct current charging system is also provided with an energy storage system connected with the direct current bus, and the energy storage system shares part of output power under the condition that the alternating current power supply network cannot meet the actual charging requirement, so that the integral loading capacity of the system is improved. Meanwhile, under the condition that the stored electric quantity of the energy storage system is insufficient, the energy storage system is charged by the alternating current power supply network.
In practical application, the charging process and the discharging process of the energy storage system are inevitably accompanied by energy loss, and the energy loss in the charging/discharging process obviously influences the economic benefit of the direct current charging system. Especially, in the discharging process of the energy storage system, if the discharging time is unreasonable, the direct current charging system can even generate negative benefits.
Disclosure of Invention
In view of the above, the present invention provides a charging system control method, a controller and a system, which control a discharging process of an energy storage system based on electricity price information to improve economic benefits of a dc charging system, and the specific scheme is as follows:
in a first aspect, the present invention provides a charging system control method, including:
acquiring a current electricity price, a preset discharging electricity price threshold value and a current electricity storage percentage of an energy storage system, wherein the preset discharging electricity price threshold value is a minimum electricity price corresponding to a target charging income acquired by the charging system;
comparing the magnitude relation between the current electricity price and the preset discharging electricity price threshold value, and the magnitude relation between the electricity storage percentage and the preset discharging proportion threshold value;
and if the current electricity price is greater than the preset discharging electricity price threshold value and the electricity storage percentage is greater than or equal to the preset discharging proportion threshold value, controlling the energy storage system to enter a discharging allowing mode.
Optionally, after the energy storage system enters the discharge allowing mode, the method further includes:
acquiring direct current bus voltage;
and if the voltage of the direct current bus is smaller than a preset discharge voltage threshold value, controlling the energy storage system to discharge to the direct current bus.
Optionally, the process of determining the preset discharging electricity price threshold includes:
acquiring historical electricity price, a preset income threshold value and charging/discharging efficiency of the energy storage system during energy storage of the energy storage system;
substituting the historical electricity price, the preset income threshold value and the charging/discharging efficiency into the following formula, and determining that the obtained result is a preset discharging electricity price threshold value:
wherein C represents the preset discharge electricity price threshold value;
b represents the historical electricity prices;
y represents the preset revenue threshold;
η 1 representing a charging efficiency of the energy storage system;
η 2 representing the discharge efficiency of the energy storage system.
Optionally, if the charging system control method is applied to a controller of the energy storage system, before or after any step, the method further includes:
acquiring a scheduling discharge instruction;
and responding to the scheduling discharge instruction, and controlling the energy storage system to discharge to the direct current bus.
Optionally, after the controlling the energy storage system to discharge to the dc bus, the method further includes:
acquiring an input current of the charging system;
and if the duration of the input current is less than or equal to the first current threshold reaches a first preset duration, controlling the energy storage system to stop discharging.
Optionally, if the charging system control method is applied to a controller of a charging system, after the controlling the energy storage system to stop discharging, the method further includes:
if the energy storage system is in a waiting mode and the duration of the input current which is greater than the first current threshold reaches a second preset duration threshold, sending a newly increased power limit value so that each charging unit in the charging system outputs charging power according to the newly increased power limit value;
wherein the waiting mode is a mode in which the energy storage system is not in the charge-allowed mode and is not in the discharge-allowed mode.
Optionally, after the obtaining the current electricity price, the preset discharging electricity price threshold, and the current electricity storage percentage of the energy storage system, the method further includes:
comparing the relation between the power storage percentage and a preset charging proportion threshold value;
if the electricity storage percentage is smaller than the preset charging proportion threshold value and meets a preset charging condition, controlling the energy storage system to enter a charging allowing mode;
wherein the preset charging condition includes:
the current electricity price is less than a preset charging electricity price threshold value;
or, under the condition that the direct current bus voltage is not less than the rated voltage, the voltage change rate of the direct current bus voltage is greater than a preset change rate threshold value;
or the difference between the voltage of the direct current bus and the rated voltage is greater than a preset voltage variation, wherein the preset voltage variation is greater than 0.
Optionally, after the energy storage system enters the charge permission mode, the method further includes:
acquiring input current and direct current bus voltage of the charging system;
and if the duration of the input current less than the second current threshold reaches a third preset duration, or the direct current bus voltage is greater than or equal to a preset charging voltage threshold, controlling the energy storage system to charge.
Optionally, after the controlling the energy storage system to charge, the method further includes:
and if the duration of the direct current bus voltage smaller than the preset charging voltage threshold reaches a fourth preset duration, or the duration of the input current larger than a third current threshold reaches a fifth preset duration, controlling the energy storage system to stop charging.
Optionally, if the charging system control method is applied to the controller of the energy storage system, after the obtaining of the current electricity price, the preset discharging electricity price threshold, and the current electricity storage percentage of the energy storage system, the method further includes:
under the condition that the power storage percentage is smaller than the preset charging proportion threshold value, a scheduling charging instruction is obtained;
and responding to the scheduling charging instruction, and controlling the energy storage system to charge.
In a second aspect, the present invention provides a controller for an energy storage system, comprising: a memory and a processor; the memory stores a program suitable for the processor to execute so as to implement the charging system control method corresponding to the controller of the energy storage system according to any one of the first aspect of the invention.
In a third aspect, the present invention provides a system controller of a charging system, comprising: a memory and a processor; the memory stores a program suitable for the processor to execute, so as to implement the charging system control method corresponding to the system controller of the charging system according to any one of the first aspect of the present invention.
In a fourth aspect, the present invention provides a charging system comprising: a system controller, an energy storage system, a centralized rectifier, a dc bus, and at least one charging unit, wherein,
the input end of the centralized rectifier is connected with a power supply network, and the output end of the centralized rectifier is connected with the direct-current bus;
the input end of each charging unit is respectively connected with the direct current bus;
the energy storage system is connected with the direct current bus;
the system controller is respectively connected with the energy storage system, the centralized rectifier and each charging unit;
the controller of the energy storage system and at least one of the system controllers are configured to execute the charging system control method according to any one of the first aspects of the present invention.
Optionally, the charging unit includes: a plurality of DC/DC converters, path selection modules with the number equal to that of the DC/DC converters, at least one charging interface and a unit controller,
the path selection module comprises an input end and at least one output end;
after the input ends of the DC/DC converters are connected in parallel, the input ends of the DC/DC converters are used as the input ends of the charging units to be connected with the direct current bus;
the output end of each DC/DC converter is connected with the input end of the path selection module which is different from the input end of the DC/DC converter;
each output end of each path selection module and each corresponding charging interface have a preset connection relation;
the unit controller is respectively connected with the control end of each path selection module, and controls the connection state of each path selection module and each charging interface according to the control instruction of the system controller.
Optionally, if the charging system includes a plurality of the centralized rectifiers, the system further includes: a split transformer, wherein,
the input end of the individual transformer is connected with a power supply network;
and each output end of the individual transformer is connected with the input end of the different centralized rectifier.
The charging system control method provided by the invention comprises the steps of firstly obtaining the current electricity price, a preset discharging electricity price threshold and the current electricity storage percentage, wherein the preset discharging electricity price threshold is the lowest electricity price corresponding to the target charging income obtained by the charging system, further comparing the magnitude relation between the current electricity price and the preset discharging electricity price threshold, and the magnitude relation between the electricity storage percentage and the preset discharging proportion threshold, and if the current electricity price is greater than the preset discharging electricity price threshold and the electricity storage percentage is greater than or equal to the preset discharging proportion threshold, controlling the energy storage system to enter the discharging allowing mode. According to the charging system control method provided by the invention, the discharging process of the energy storage system is controlled by referring to the magnitude relation between the current electricity price of the power supply network and the preset discharging electricity price threshold, the phenomenon that the income of the charging system is reduced due to unreasonable discharging opportunity selection is avoided, and the economic benefit of the direct current charging system is effectively improved.
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 introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic diagram of a system architecture of a dc charging system in the prior art;
fig. 2 is a flowchart of a charging system control method according to an embodiment of the present invention;
fig. 3 is a flowchart of another charging system control method according to an embodiment of the present invention;
fig. 4 is a block diagram of a controller of an energy storage system according to an embodiment of the present invention;
fig. 5 is a block diagram of a system controller of a charging system according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a charging unit in a charging system according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a path selection module in a charging system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 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.
An embodiment of the present invention provides a charging system control method, and referring to fig. 1, fig. 1 is a flowchart of the charging system control method provided in the embodiment of the present invention, and the method may be applied to a controller, such as a system controller in a charging system or a controller of an energy storage system, which is capable of acquiring preset information, executing a preset calculation program, and outputting a calculation result or a control instruction according to the obtained preset information, in a dc charging system, obviously, a server on a network side may also be used to execute the charging system control method provided in the embodiment of the present invention in some cases; referring to fig. 1, a method for controlling a charging system according to an embodiment of the present invention may include:
s100, obtaining the current electricity price, a preset discharging electricity price threshold value and the current electricity storage percentage of the energy storage system.
Optionally, the current electricity price information may be obtained by accessing an internet, and of course, if the charging system is capable of obtaining the current latest electricity price information, the controller executing the method provided by the embodiment of the present invention may also directly obtain the latest current electricity price from the charging system. The embodiment of the invention does not specifically limit the specific acquisition mode of the current electricity price and the information source.
And the acquisition of the electricity storage percentage can directly access the corresponding storage device in the charging system to acquire the information of the electric quantity stored in the storage device. In the prior art implementation manner, the calculation and storage of the power storage percentage are implemented by corresponding technologies, and the present invention is not limited to this.
As for the acquisition process of the preset discharge electricity price threshold, specific calculation needs to be performed by combining the historical electricity price, the preset income threshold set by the user, and the performance parameters of the energy storage system. This means that, in different situations, the preset discharging electricity price threshold provided by the embodiment of the present invention may be different, but no matter how the preset discharging electricity price threshold changes, the characteristic that the preset discharging electricity price threshold is used as the lowest electricity price for the charging system to obtain the target charging income is unchanged, that is, only in the case that the current electricity price is greater than the preset discharging electricity price threshold, the energy storage system discharges electricity, and the income may be obtained.
Optionally, an embodiment of the present invention provides a method for calculating a preset discharge electricity price threshold, where the specific calculation method is as follows:
assuming that the current electricity price is A, the historical electricity price when the energy storage system stores electric energy is B, the charging efficiency of the energy storage system is eta 1, the discharging efficiency is eta 2, and the charging amount of the energy storage system in the last charging process is E. Based on the above, in order to realize positive benefits in the discharge process of the energy storage system, the following formula (1) needs to be satisfied:
E·η1·η2·A-E·B＞0 (1)
the most conservative power price relationship represented by the formula (2) can be obtained by transforming the formula (1):
in consideration of certain economy, that is, a user wishes to realize a certain economic benefit, a preset benefit threshold value Y may be set, based on which equation (1) may be set to equation (3), where the preset benefit threshold value Y refers to a benefit threshold value per degree of electricity, Y >0, and when Y =0, it is equivalent to the case expressed by equation (1).
E·η1·η2·A-E·B＞E·Y (3)
If equation (3) is appropriately transformed, an equation for calculating the preset discharge electricity price threshold, that is, equation (4), can be obtained:
based on the calculation formula (4), the historical electricity price when the energy storage system stores energy, the preset income threshold value set in advance and the specific charging efficiency and discharging efficiency of the energy storage system are obtained, the obtained parameters are substituted into the calculation formula (4), and the obtained calculation result is the preset discharging electricity price threshold value.
And S110, comparing the size relation between the current electricity price and a preset discharging electricity price threshold value, and comparing the size relation between the electricity storage percentage and a preset discharging proportion threshold value.
After obtaining the required information, the relationship between the current electricity price and the preset discharge electricity price threshold needs to be further compared, and meanwhile, the relationship between the electricity storage percentage and the preset discharge proportion threshold needs to be compared.
The preset discharge proportion threshold is artificially set according to the self characteristics of the energy storage system and the running state of the charging system and by combining running experience.
And S120, controlling the energy storage system to enter a discharging allowing mode under the condition that the current electricity price is larger than a preset discharging electricity price threshold value and the electricity storage percentage is larger than or equal to a preset discharging proportion threshold value.
The current electricity price is larger than a preset discharging electricity price threshold value, which indicates that the basic income requirement can be met; the power storage percentage is larger than or equal to the preset discharge proportion threshold, which indicates that the energy storage system meets the corresponding discharge requirement, the charging object can be charged through the direct current bus, and the energy storage system can be controlled to enter the discharge allowing mode under the condition that the two judgment conditions are met.
In summary, the charging system control method provided by the invention refers to the magnitude relation between the current electricity price of the power supply network and the preset discharging electricity price threshold value, and combines the actual operation condition of the energy storage system to control the discharging process of the energy storage system, so that the reduction of the benefit of the charging system due to the unreasonable selection of the discharging time is avoided, and the economic benefit of the direct current charging system is effectively improved.
Optionally, after the energy storage system is controlled to enter the discharge-allowed mode, the dc bus voltage of the dc bus connected to the energy storage system is further obtained, and if the dc bus voltage is smaller than a preset discharge voltage threshold, it is determined that the energy storage system is required to provide additional charging power output, the energy storage system is controlled to discharge to the dc bus, so as to improve the load carrying capacity of the charging system.
It can be thought that, as the energy storage system discharges to the dc bus, the load pressure of the centralized rectifier in the charging system is definitely shared, the electric energy obtained by the charging system from the ac power grid will be reduced to a certain extent, further, charging objects may also finish charging successively, and under the condition that the output power of the energy storage system is certain, the total input current of the charging system is definitely reduced gradually.
In order to reduce the consumption of the stored electric energy in the energy storage system, the control method provided by the embodiment of the invention further monitors the input current of the charging system after controlling the energy storage system to discharge to the direct current bus, and controls the energy storage system to stop discharging if the duration of the input current of the charging system being less than or equal to the first current threshold reaches a first preset duration, and then the direct current system directly provides the charging power required by the charging object.
It should be particularly emphasized that, as described above, the charging system control method provided in each of the above embodiments may be applied to a system controller of a charging system, and may also be applied to a controller of an energy storage system, where if the charging system control method is applied to the system controller, the system controller must transmit a corresponding control instruction to the energy storage system in a communication manner when controlling a discharging process of the energy storage system, and the transmission of the control instruction is bound to be accompanied by a certain delay, so that the energy storage system cannot timely and rapidly provide electric energy to a dc bus, and dynamic response performance of the entire charging system is affected. Therefore, as a preferred implementation manner, the controller of the energy storage system executes the control method provided in any of the above embodiments, so that the energy storage system realizes autonomous discharge process control, and avoids time delay caused by an instruction transmission process, thereby improving the overall dynamic response performance of the charging system.
Optionally, when the energy storage system actively discharges, the system controller may further send active discharge state information to the system controller synchronously, and when the system controller stops actively discharging, the system controller may send active discharge stop state information to the system controller, so as to ensure that the system controller can timely learn the working state of the energy storage system, and further perform corresponding control.
Under the condition that the energy storage system performs autonomous discharge process control, the energy storage system can also receive a scheduling discharge instruction sent by a system controller of the charging system, and passively discharges to the direct-current bus according to the obtained scheduling discharge instruction, namely, the combination of active control and passive control is realized. As for the timing and the determination condition for the system controller to send the scheduling discharge command, the timing and the determination condition may be implemented according to an implementation manner in the prior art, which is not specifically limited in the present invention.
Based on the above, the charging system control method provided by the invention can realize multiple control modes of active discharge and passive discharge for the energy storage system, and can improve the overall dynamic response capability of the charging system and the stability of the charging system on the premise of ensuring the expected economic benefit.
Optionally, the invention further provides a control method of the charging process of the energy storage system. Referring to fig. 3, fig. 3 is a flowchart of another charging system control method provided in an embodiment of the present invention, where the control method provided in this embodiment may further include:
and S200, acquiring the current electricity price and the current electricity storage percentage of the energy storage system.
Optionally, an optional implementation manner of S200 may be implemented by referring to the step of S100 in the embodiment shown in fig. 2, or the current electricity price obtained in the step of S100 and the current electricity storage percentage of the energy storage system may be directly used.
And S210, comparing the relation between the power storage percentage and a preset charging ratio threshold value.
Similar to the preset discharge ratio threshold, the preset charge ratio threshold is provided in the embodiment of the present invention, if the current power storage percentage of the energy storage system is less than the preset charge ratio threshold, it may be determined that the energy storage system needs to be charged, and conversely, if the current power storage percentage of the energy storage system is greater than or equal to the preset charge ratio threshold, the energy storage system may not be charged temporarily.
Optionally, in practical application, the preset charging ratio threshold and the preset discharging ratio threshold may be set to be the same threshold, and the same threshold is used for determining the two working conditions.
And S220, controlling the energy storage system to enter a charging allowing mode under the condition that the power storage percentage is smaller than a preset charging ratio threshold value and a preset charging condition is met.
In order to more carefully control the charging process of the energy storage system, the embodiment of the present invention further provides a preset charging condition for determining whether the energy storage system needs to be charged, where the preset charging condition includes:
the current electricity price is less than a preset charging electricity price threshold value;
or under the condition that the voltage of the direct current bus is not less than the rated voltage, the voltage change rate of the voltage of the direct current bus is greater than a preset change rate threshold value;
or the difference between the voltage of the direct current bus and the rated voltage is larger than a preset voltage variation, wherein the preset voltage variation is larger than 0.
And under the condition that the power storage percentage is smaller than the preset charging proportion threshold, the energy storage system can be controlled to enter a charging allowing mode when any one of the three conditions is met.
It is conceivable that, for the second and third bars, the change condition of the dc bus voltage is mainly examined, and it is satisfied that either one of the two bars indicates that the dc bus voltage is significantly increased on the basis of the rated voltage, and the increase of the dc bus voltage corresponds to a light load of the charging system.
Optionally, for the second and third preset charging conditions, a preset charging ratio threshold with a higher value may also be set, for example, a second preset charging ratio threshold is set, and the preset charging ratio threshold with the smaller value is defined as a first preset charging ratio threshold, so that: even if the stored electric quantity in the energy storage system is higher, as long as the electric storage percentage is smaller than the second preset charging proportion threshold value, and the voltage of the direct-current bus is obviously increased, the energy storage system can be directly controlled to enter a charging allowing mode, so that the energy storage system can be timely charged when the load of the charging system is lighter.
In summary, the charging system control method provided in the embodiment of the present invention combines the magnitude relationship between the current electricity price and the preset charging electricity price threshold and the change condition of the dc bus voltage to control the charging process of the energy storage system, comprehensively considers the actual operation condition and the charging cost of the charging system, and reasonably controls the selection of the charging time, so that the charging with low cost can be realized under the condition that the charging system is normally operated, and the economic benefit of the energy storage system can be improved.
Optionally, after the energy storage system enters the charging permission mode, the input current and the dc bus voltage of the charging system may be further obtained, and if the duration that the input current of the charging system is smaller than the second current threshold reaches a third preset duration, or the dc bus voltage is greater than or equal to the preset charging voltage threshold, the energy storage system is controlled to be charged. The second current threshold is smaller than the first current threshold, and the preset charging voltage threshold is larger than the preset discharging voltage threshold.
It is conceivable that the examination of the input current of the charging system mainly ensures that the input side of the charging system, especially the load of the centralized rectifier, is not too large to affect the normal operation of the charging system or affect the charging object still being charged in the charging system after the energy storage system starts charging. And for the examination of the voltage of the direct current bus, the load condition of the charging system is mainly measured, and the direct current bus voltage is greater than or equal to the preset charging voltage threshold value, which indicates that the load of the direct current bus is light, so that the charging process of the energy storage system can be carried out.
When the energy storage system is charged, the energy storage system is equivalent to a load connected to the direct current bus and can influence the voltage of the direct current bus and the input current of the charging system, and therefore after the energy storage system starts to be charged, if the duration that the voltage of the direct current bus is smaller than a preset charging voltage threshold reaches a fourth preset duration, or the duration that the input current of the charging system is larger than a third current threshold reaches a fifth preset duration, the energy storage system is controlled to stop charging.
It should be particularly emphasized that, like the discharging process of the energy storage system, the charging system control method provided in the foregoing embodiments may be applied to a system controller of the charging system, and may also be applied to a controller of the energy storage system, if the charging system control method is applied to the system controller, when the system controller controls the charging process of the energy storage system, the system controller must transmit a corresponding control command to the energy storage system in a communication manner, and a transmission delay of the control command may also affect a dynamic response performance of the entire charging system. Therefore, as a preferred implementation manner, the controller of the energy storage system executes the control method of the charging process provided in any of the above embodiments, so that the energy storage system realizes autonomous control of the charging process, and avoids time delay caused by an instruction transmission process, thereby improving the overall dynamic response performance of the charging system.
Optionally, when the energy storage system is actively charged, the active charging state information may be sent to the system controller synchronously, and when the active charging is stopped, the active charging state stopping information may be sent to the system controller, so as to ensure that the system controller can timely learn the working state of the energy storage system, and further perform corresponding control.
Similarly, under the condition that the energy storage system performs autonomous charging process control, the energy storage system can also receive a scheduled charging instruction sent by a system controller of the charging system, and under the condition that the power storage percentage is smaller than a preset charging proportion threshold value, the energy storage system performs a charging process passively according to the obtained scheduled charging instruction. As for the timing and the determination condition for the system controller to send the scheduling charging command, the timing and the determination condition may be implemented according to an implementation manner in the prior art, which is not specifically limited in the present invention.
In practical applications, the energy storage system may not be in the above-mentioned charging-enabled mode, and also may not belong to the above-mentioned discharging-enabled mode, and the method provided by the embodiment of the present invention defines this operation mode of the energy storage system as the waiting mode. When the energy storage system is in a waiting mode, a system controller of the charging system monitors input current of the charging system, when the duration time that the input current is greater than a first current threshold reaches a second preset time threshold, in order to avoid overload of the charging system, the system controller sends a newly increased power limit value to all charging units in the system in a broadcast communication mode, after each charging unit receives the newly increased power limit value, if a charging object is charged, the existing state is maintained, and if the charging object is prepared to be output electric energy, after the charging object is connected, the charging power is output according to the newly increased power limit value, and further increase of the load of the charging system is avoided.
In the waiting mode, the energy storage system continuously acquires the current electricity price and the electricity storage percentage, and waits for a scheduling command so as to switch to the charging allowing mode or the discharging allowing mode at any time.
Optionally, fig. 4 is a hardware structure diagram of a controller of an energy storage system according to an embodiment of the present invention, which is shown in fig. 4 and includes: the method can comprise the following steps: at least one processor 100, at least one communication interface 200, at least one memory 300, and at least one communication bus 400;
in the embodiment of the present invention, the number of the processor 100, the communication interface 200, the memory 300, and the communication bus 400 is at least one, and the processor 100, the communication interface 200, and the memory 300 complete the communication with each other through the communication bus 400; it is clear that the communication connections shown by the processor 100, the communication interface 200, the memory 300 and the communication bus 400 shown in fig. 4 are merely optional;
optionally, the communication interface 200 may be an interface of a communication module, such as an interface of a GSM module;
the processor 100 may be a central processing unit CPU or an Application Specific Integrated Circuit ASIC or one or more Integrated circuits configured to implement embodiments of the present invention.
The processor 100 is specifically configured to execute an application program in the memory, so as to implement the charging system control method executable by the controller of the energy storage system.
Optionally, fig. 5 is a hardware structure diagram of a server provided in the embodiment of the present invention, which is shown in fig. 5 and includes: the method can comprise the following steps: at least one processor 500, at least one communication interface 600, at least one memory 700, and at least one communication bus 800;
in the embodiment of the present invention, the number of the processor 500, the communication interface 600, the memory 700, and the communication bus 800 is at least one, and the processor 500, the communication interface 600, and the memory 700 complete the communication with each other through the communication bus 800; it should be apparent that the communication connections shown by processor 500, communication interface 600, memory 700, and communication bus 800 shown in FIG. 5 are merely optional;
optionally, the communication interface 600 may be an interface of a communication module, such as an interface of a GSM module;
the processor 500 may be a central processing unit CPU, or an Application Specific Integrated Circuit (ASIC), or one or more Integrated circuits configured to implement an embodiment of the invention.
The processor 500 is specifically configured to execute an application program in the memory, so as to implement the charging system control method executable by the system controller of the charging system.
Optionally, an embodiment of the present invention further provides a charging system, including: a system controller, an energy storage system, a centralized rectifier, a dc bus, and at least one charging unit, wherein,
the input end of the centralized rectifier is connected with a power supply network, and the output end of the centralized rectifier is connected with the direct current bus;
the input end of each charging unit is respectively connected with the direct current bus;
the energy storage system is connected with the direct current bus;
the system controller is respectively connected with the energy storage system, the centralized rectifier and each charging unit;
the controller of the energy storage system and at least one of the system controllers are configured to perform the corresponding charging system control method of any of the above method embodiments.
Optionally, referring to fig. 6, fig. 6 is a schematic structural diagram of a charging unit in a charging system provided in an embodiment of the present application, where the charging unit includes: a plurality of DC/DC converters, a number of path selection modules equal to the number of DC/DC converters (fig. 7 shows an alternative structural schematic of the path selection modules), at least one charging interface (shown as O1-On in fig. 6), and a unit controller (not shown in the figure), wherein,
the path selection module comprises an input end and at least one output end;
the input ends of the DC/DC converters are connected in parallel and then are used as the input ends of the charging units to be connected with the direct current bus;
the output end of each DC/DC converter is connected with the input end of the different path selection module;
each output end of each path selection module and each corresponding charging interface have a preset connection relation;
the unit controller is respectively connected with the control end of each path selection module and controls the connection state of each path selection module and each charging interface according to the control instruction of the system controller.
Optionally, if the charging system comprises a plurality of centralized rectifiers, the charging system further comprises a split transformer, wherein,
the input end of the sectional transformer is connected with a power supply network, and the output ends of the sectional transformer are connected with the input ends of the different centralized rectifiers.
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 controller disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for relevant points, reference may be made to the description of the method part.
Those of skill would further appreciate that the various illustrative components and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the components and steps of the various examples have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (14)
1. A charging system control method, comprising:
acquiring a current electricity price, a preset discharging electricity price threshold value and a current electricity storage percentage of an energy storage system, wherein the preset discharging electricity price threshold value is a minimum electricity price corresponding to a target charging income acquired by the charging system;
comparing the magnitude relation between the current electricity price and the preset discharging electricity price threshold value, and the magnitude relation between the electricity storage percentage and the preset discharging proportion threshold value;
if the current electricity price is larger than the preset discharging electricity price threshold value and the electricity storage percentage is larger than or equal to the preset discharging proportion threshold value, controlling the energy storage system to enter a discharging allowing mode;
wherein, if the charging system control method is applied to a controller of the energy storage system, before and after any step, the method further comprises:
acquiring a scheduling discharge instruction;
and responding to the scheduling discharge instruction, and controlling the energy storage system to discharge to the direct current bus.
2. The charging system control method according to claim 1, further comprising, after the energy storage system enters the discharge-allowed mode:
acquiring direct current bus voltage;
and if the voltage of the direct current bus is smaller than a preset discharge voltage threshold value, controlling the energy storage system to discharge to the direct current bus.
3. The charging system control method according to claim 1, wherein the process of determining the preset discharging electricity price threshold value includes:
acquiring historical electricity price, a preset income threshold value and charging/discharging efficiency of the energy storage system during energy storage of the energy storage system;
substituting the historical electricity price, the preset income threshold value and the charging/discharging efficiency into the following formula, and determining that the obtained result is a preset discharging electricity price threshold value:
wherein C represents the preset discharge electricity price threshold;
b represents the historical electricity price;
y represents the preset revenue threshold;
η 1 representing a charging efficiency of the energy storage system;
η 2 representing the discharge efficiency of the energy storage system.
4. The charging system control method according to claim 2, further comprising, after the controlling the energy storage system to discharge to a dc bus:
acquiring an input current of the charging system;
and if the duration of the input current is less than or equal to the first current threshold reaches a first preset duration, controlling the energy storage system to stop discharging.
5. The charging system control method according to claim 4, wherein if the charging system control method is applied to a controller of a charging system, after the controlling the energy storage system to stop discharging, the method further comprises:
if the energy storage system is in a waiting mode and the duration of the input current which is greater than the first current threshold reaches a second preset duration threshold, sending a newly increased power limit value so that each charging unit in the charging system outputs charging power according to the newly increased power limit value;
the waiting mode is a mode in which the energy storage system is not in a charging-allowed mode and is not in a discharging-allowed mode.
6. The charging system control method according to claim 1, further comprising, after the obtaining the current electricity price, the preset discharging electricity price threshold, and the current electricity storage percentage of the energy storage system:
comparing the relation between the power storage percentage and a preset charging proportion threshold value;
if the electricity storage percentage is smaller than the preset charging proportion threshold value and meets a preset charging condition, controlling the energy storage system to enter a charging allowing mode;
wherein the preset charging condition includes:
the current electricity price is less than a preset charging electricity price threshold value;
or, under the condition that the direct current bus voltage is not less than the rated voltage, the voltage change rate of the direct current bus voltage is greater than a preset change rate threshold value;
or the difference value between the voltage of the direct current bus and the rated voltage is larger than a preset voltage variation, wherein the preset voltage variation is larger than 0.
7. The charging system control method according to claim 6, further comprising, after the energy storage system enters the charge permission mode:
acquiring input current and direct current bus voltage of the charging system;
and if the duration of the input current less than the second current threshold reaches a third preset duration, or the direct current bus voltage is greater than or equal to a preset charging voltage threshold, controlling the energy storage system to charge.
8. The charging system control method according to claim 7, further comprising, after the controlling of the charging of the energy storage system:
and if the duration of the direct current bus voltage smaller than the preset charging voltage threshold reaches a fourth preset duration, or the duration of the input current larger than a third current threshold reaches a fifth preset duration, controlling the energy storage system to stop charging.
9. The method according to claim 6, wherein if the charging system control method is applied to the controller of the energy storage system, after the obtaining the current electricity price, the preset discharging electricity price threshold, and the current electricity storage percentage of the energy storage system, the method further comprises:
under the condition that the power storage percentage is smaller than the preset charging proportion threshold value, a scheduling charging instruction is obtained;
and responding to the scheduling charging instruction, and controlling the energy storage system to be charged.
10. A controller for an energy storage system, comprising: a memory and a processor; the memory stores a program adapted to be executed by the processor to implement the charging system control method according to any one of claims 1 to 4 and 6 to 9.
11. A system controller of a charging system, comprising: a memory and a processor; the memory stores a program adapted to be executed by the processor to implement the charging system control method according to any one of claims 1 to 9.
12. An electrical charging system, comprising: a system controller, an energy storage system, a centralized rectifier, a dc bus, and at least one charging unit, wherein,
the input end of the centralized rectifier is connected with a power supply network, and the output end of the centralized rectifier is connected with the direct current bus;
the input end of each charging unit is respectively connected with the direct current bus;
the energy storage system is connected with the direct current bus;
the system controller is respectively connected with the energy storage system, the centralized rectifier and each charging unit;
the controller of the energy storage system and at least one of the system controllers are configured to perform the charging system control method of any one of claims 1 to 9.
13. The charging system according to claim 12, wherein the charging unit includes: a plurality of DC/DC converters, path selection modules with the number equal to that of the DC/DC converters, at least one charging interface and a unit controller,
the path selection module comprises an input end and at least one output end;
after the input ends of the DC/DC converters are connected in parallel, the input ends of the DC/DC converters are used as the input ends of the charging units to be connected with the direct current bus;
the output end of each DC/DC converter is connected with the input end of the path selection module which is different from the input end of the DC/DC converter;
each output end of each path selection module and each corresponding charging interface have a preset connection relation;
the unit controller is respectively connected with the control end of each path selection module, and controls the connection state of each path selection module and each charging interface according to the control instruction of the system controller.
14. The charging system according to claim 12 or 13, wherein if the charging system includes a plurality of the centralized rectifiers, the system further comprises: a split transformer, wherein,
the input end of the line-splitting transformer is connected with a power supply network;
and each output end of the individual transformer is connected with the input end of the different centralized rectifier.
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| CN114204631A (en) * | 2021-12-01 | 2022-03-18 | 始途科技(杭州)有限公司 | Discharging control method, charging control method and device |
| CN115995839B (en) * | 2023-02-27 | 2023-10-13 | 国网浙江电动汽车服务有限公司 | Method, device, equipment and medium for determining working state of multifunctional mobile energy storage vehicle |
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