CN111064263B - Voltage control method, photovoltaic power supply device and system - Google Patents
Voltage control method, photovoltaic power supply device and system Download PDFInfo
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- CN111064263B CN111064263B CN202010014685.0A CN202010014685A CN111064263B CN 111064263 B CN111064263 B CN 111064263B CN 202010014685 A CN202010014685 A CN 202010014685A CN 111064263 B CN111064263 B CN 111064263B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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Abstract
The embodiment of the invention provides a voltage control method, a photovoltaic power supply device and a photovoltaic power supply system, relates to the field of new energy, and is used for improving the energy utilization rate of a photovoltaic power supply system, and the method comprises the following steps: the photovoltaic power supply device acquires a first system parameter; the first system parameters comprise the output voltage of the photovoltaic power supply device and the direct current bus voltage; the photovoltaic power supply device determines the charging state of the direct current power supply device according to the voltage of the direct current bus; the charging state comprises current-limiting charging and voltage-limiting charging; the photovoltaic power supply device adjusts output voltage according to the direct current bus voltage and the charging state. The photovoltaic power supply device is used for dynamically adjusting the output voltage of the photovoltaic power supply device.
Description
Technical Field
The invention relates to the field of new energy, in particular to a voltage control method, a photovoltaic power supply device and a photovoltaic power supply system.
Background
The photovoltaic power supply system at present comprises a photovoltaic power supply device, a direct current power supply device and a direct current bus connected with the photovoltaic power supply device, wherein the photovoltaic power supply device and the direct current power supply device are generally powered in a time-sharing mode. According to the charging and discharging states of the storage battery pack in the photovoltaic power supply system, the running state of the direct current power supply device can comprise a floating charging state, a discharging state and an even charging state. When the dc power supply device is in the uniform charging state, the dc bus voltage changes in real time, and the output voltage of the photovoltaic power supply device is generally output in a static output manner, so that when the dc bus voltage becomes large, the output voltage of the photovoltaic power supply device may be smaller than the dc bus voltage, which causes the electric energy of the photovoltaic power supply device to be unable to be output, and the photovoltaic energy to be wasted.
Disclosure of Invention
The embodiment of the invention provides a voltage control method, a photovoltaic power supply device and a photovoltaic power supply system, which are used for dynamically adjusting the output voltage of a photovoltaic power supply system and improving the energy utilization rate of the photovoltaic power supply system.
In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:
in a first aspect, a voltage control method is provided, which is applied to a photovoltaic power supply system, where the photovoltaic power supply system includes a dc bus, and a photovoltaic power supply device and a dc power supply device that are connected to the dc bus, and the method includes: the photovoltaic power supply device acquires a first system parameter; the first system parameters comprise the output voltage of the photovoltaic power supply device and the direct current bus voltage; the photovoltaic power supply device determines the charging state of the direct current power supply device according to the voltage of the direct current bus; the charging state comprises current-limiting charging and voltage-limiting charging; the photovoltaic power supply device adjusts output voltage according to the direct current bus voltage and the charging state.
In a second aspect, a photovoltaic power supply apparatus is provided, including: the communication module is used for acquiring direct-current bus voltage from the direct-current power supply device; the acquisition module is used for acquiring the output voltage of the photovoltaic power supply device; the processing module is used for determining the charging state of the direct current power supply device according to the direct current bus voltage acquired by the communication module; the charging state comprises current-limiting charging and voltage-limiting charging; and the adjusting module is used for adjusting the output voltage obtained by the obtaining module according to the direct current bus voltage obtained by the communication module and the charging state determined by the processing module.
In a third aspect, a photovoltaic power supply system is provided, including: the photovoltaic power supply device is used for converting solar energy into electric energy and supplying power to a direct current load; the direct current power supply device is used for supplying power to a direct current load and charging the storage battery pack; the direct current bus is used for transmitting the electric energy of the photovoltaic power supply device and the direct current power supply device to the storage battery pack and the direct current load; and the storage battery pack is used for storing energy and supplying power to the direct current load when the direct current power supply device is powered off.
The embodiment of the invention provides a voltage control method, a photovoltaic power supply device and a photovoltaic power supply system, wherein the method comprises the following steps: the photovoltaic power supply device acquires a first system parameter; the first system parameters comprise the output voltage of the photovoltaic power supply device and the direct current bus voltage; the photovoltaic power supply device determines the charging state of the direct current power supply device according to the voltage of the direct current bus; the charging state comprises current-limiting charging and voltage-limiting charging; the photovoltaic power supply device adjusts output voltage according to the direct current bus voltage and the charging state. According to the photovoltaic power supply system provided by the embodiment of the invention, when the direct current power supply device is in the uniform charging state, the output voltage of the photovoltaic power supply device can be adjusted in real time according to the voltage change of the direct current bus in the current-limiting charging state and the voltage-limiting charging state, so that the photovoltaic power supply device is ensured to supply power to a direct current load, and meanwhile, the overcharge of a storage battery pack is avoided.
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, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a photovoltaic power supply system according to an embodiment of the present invention;
fig. 2 is a first schematic flow chart of a voltage control method according to an embodiment of the present invention;
fig. 3 is a schematic diagram of dc bus voltages of a dc power supply device in different operating states according to an embodiment of the present invention;
fig. 4 is a schematic flow chart of a voltage control method according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a photovoltaic power supply apparatus according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that, in the embodiments of the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "e.g.," an embodiment of the present invention is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion.
For the convenience of clearly describing the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, the words "first", "second", and the like are used for distinguishing the same items or similar items with basically the same functions and actions, and those skilled in the art can understand that the words "first", "second", and the like are not limited in number or execution order.
In the existing photovoltaic power supply system, the output voltage of the photovoltaic power supply device keeps static output. When the direct current power supply device is in a uniform charging state, the voltage of the direct current bus changes in real time according to the charging progress of the storage battery pack, so that if the photovoltaic power supply device keeps static output, the access voltage of the photovoltaic power supply device to the direct current bus is possibly smaller than the voltage of the direct current bus, the photovoltaic power supply device cannot supply power to a direct current load, and photovoltaic energy is wasted.
In view of the above problem, as shown in fig. 1, an embodiment of the present invention provides a photovoltaic power supply system, including: the photovoltaic power supply device 01, the direct current power supply device 02, the direct current bus 03, the storage battery 04 and the direct current load 05.
Referring to fig. 1, the output end of the photovoltaic power supply device 01 and the output end of the dc power supply device 02 are connected to a dc bus 03, the input end of the storage battery 04 and the input end of the dc load 05 are connected to the dc bus 03, and the photovoltaic power supply device 01 and the dc power supply device 02 transmit electric energy to the storage battery 04 and the dc load 05 through the dc bus 03. Note that the voltages at the positions on the dc bus 03 are the same.
The photovoltaic power supply device 01 is used for converting solar energy into electric energy and supplying power to the direct current load 05.
A dc power supply device 02 for supplying power to the dc load 05 and charging the battery pack 04.
And the direct-current bus 03 is used for transmitting the electric energy of the photovoltaic power supply device 01 and the direct-current power supply device 02 to the storage battery group 04 and the direct-current load 05.
And the storage battery group 04 is used for storing energy and supplying power to the direct current load 05 when the direct current power supply device 02 is powered off.
Specifically, the power generation power of the photovoltaic power supply device 01 is smaller than the power of the direct-current load 05, the photovoltaic power supply device 01 cannot supply power to the direct-current load 05 alone, the photovoltaic power supply device 01 and the direct-current power supply device 02 or the storage battery 04 can supply power to the direct-current load 05 together, and the direct-current power supply device 02 can supply power to the direct-current load 05 only.
Optionally, the photovoltaic power supply apparatus 01 includes a photovoltaic panel 011, a photovoltaic controller 012, and an analysis module 013, and the dc power supply apparatus 02 includes a utility power 021, a rectification device 022, and a monitoring module 023.
And the photovoltaic panel 011 is used for converting solar energy into electric energy and supplying power to the direct current load 05.
And the photovoltaic controller 012 is configured to adjust the output current and the output voltage of the photovoltaic panel 011, so that the photovoltaic power supply device 01 continuously supplies power to the dc load 05 and outputs the voltage at the maximum power point.
An analysis module 013, configured to obtain a first system parameter; the first system parameter is a system parameter of the photovoltaic power supply system, including the output voltage of the photovoltaic controller 012;
the analyzing module 013 is further configured to adjust an output voltage of the photovoltaic controller 012 according to an operation state of the dc power supply device 02, so that the photovoltaic power supply device 01 continuously supplies power to the dc load 05.
Specifically, the first system parameter further includes: the input current, the input voltage, and the output current of the photovoltaic controller 012, as well as the operating start voltage of the photovoltaic controller 012 and the line resistance between the photovoltaic controller 012 and the dc bus 03.
And the mains supply 021 is used for charging the storage battery 04 and supplying power to the direct-current load 05.
And a rectifying device 022 for converting the ac power of the utility power 021 into dc power and supplying a charging voltage to the battery pack 04.
A monitoring module 023 configured to obtain a second system parameter; the second system parameters comprise direct current bus voltage and terminal voltage of the storage battery pack 04;
the monitoring module 023 is further configured to determine an operating state of the dc power supply device 02 according to the terminal voltage of the battery pack 04.
Optionally, when the dc power supply device 02 is in different operation states, the dc bus 03 has different voltage values, so the monitoring module 023 may determine the operation state of the dc power supply device 02 according to the dc bus voltage.
It is noted that the first system parameter may include a second system parameter, and the first system parameter and the second system parameter may be acquired by the analysis module 013; of course, the first system parameter may not include the second system parameter, and in this case, the analysis module 013 may obtain the parameter information collected by the monitoring module 023 through communication with the monitoring module 023.
According to the above photovoltaic power supply system, as shown in fig. 2, an embodiment of the present invention provides a voltage control method applied to a photovoltaic power supply system, where the photovoltaic power supply system includes a dc bus, and a photovoltaic power supply device and a dc power supply device connected to the dc bus, and the method is used to dynamically adjust an output voltage of the photovoltaic power supply device when the dc power supply device is in a charge balancing state, and specifically includes:
101. the photovoltaic power supply device obtains a first system parameter.
The first system parameter comprises the output voltage of the photovoltaic power supply device and the direct-current bus voltage.
Specifically, the first system parameter may be acquired by an analysis module of the photovoltaic power supply device and a monitoring module of the dc power supply device, and if the analysis module can acquire the output voltage of the photovoltaic power supply device, the monitoring module can acquire the dc bus voltage. The analysis module may obtain the system parameters acquired by the monitoring module through communication with the monitoring module, and the communication between the analysis module and the monitoring module may be wired communication or wireless communication, which is not limited in the embodiments of the present invention.
It should be noted that, in the embodiment of the present invention, the output voltage of the photovoltaic power supply apparatus is also the output voltage of the photovoltaic controller.
102. And determining the charging state of the direct current power supply device according to the direct current bus voltage.
Wherein the charging state comprises current-limiting charging and voltage-limiting charging.
Specifically, the charging equalization state includes current-limiting charging and voltage-limiting charging, and the dc bus voltage has different voltage values in different charging states, so that the output voltage of the photovoltaic power supply device should be adjusted accordingly when the dc power supply device is in different charging states. When the direct current power supply device is in the uniform charging state, the direct current bus voltage is smaller than the floating charging voltage of the storage battery pack, and the change of the direct current bus voltage in the current-limiting charging stage and the voltage-limiting charging stage is different, so that the charging state of the direct current power supply device can be determined according to the change of the direct current bus voltage. The float voltage is a terminal voltage at which the battery pack maintains a float state.
For example, the charging state of the dc power supply device may be determined by the monitoring module of the dc power supply device according to the dc bus voltage, as shown in fig. 3, during the time period T1, the dc power supply device is in the floating charging state, and the dc bus voltage is maintained at the floating charging voltage; in the T2 time period, the direct current power supply device is in a discharging state, and the voltage of the direct current bus is gradually reduced from the floating charging voltage to a cut-off voltage; in a T3 time period, the direct current power supply device is in a current-limiting charging state, and the voltage of the direct current bus is gradually increased from a cut-off voltage to an overload voltage; in a T4 time period, the direct current power supply device is in a voltage-limiting charging state, and the voltage of a direct current bus is gradually reduced from cut-off voltage to float charging voltage; and in the T4 time period, the direct current power supply device enters the floating charging state again, and the direct current bus voltage is kept at the floating charging voltage. Referring to fig. 3, the monitoring module may determine the charging state of the dc power supply device according to a change in the dc bus voltage.
103. And adjusting the output voltage according to the DC bus voltage and the charging state.
Specifically, in order to avoid the waste of photovoltaic energy, when the voltage of the direct current bus changes according to the change of the charging state, the output voltage of the photovoltaic power supply device is adjusted in real time, so that the access voltage corresponding to the output voltage of the photovoltaic power supply device is larger than the voltage of the direct current bus.
Optionally, the first system parameter further includes an output current of the photovoltaic power supply device and an overload voltage of the storage battery pack, and the output current of the photovoltaic power supply device is also an output current of the photovoltaic controller. As shown in fig. 4, when the dc power supply device is in the current-limiting charging state, step 103 includes:
1031. and if the first difference value between the overload voltage and the direct current bus voltage is greater than or equal to a first preset value, adjusting the output voltage to enable the output voltage to be in a preset range corresponding to the first access voltage.
The overload voltage is the maximum voltage for charging the storage battery pack, and the first access voltage is the voltage for accessing the photovoltaic power supply device to the direct-current bus.
Specifically, when the dc power supply device is in a current-limiting charging state, the dc power supply device charges the storage battery pack, and the dc bus voltage gradually increases to an overload voltage. When the direct current power supply device is in a current-limiting charging state, the photovoltaic power supply device supplies power to the direct current load at the same time, and the first access voltage is larger than the direct current bus voltage. Therefore, when the voltage of the dc bus reaches the overload voltage, if the photovoltaic power supply device continues to supply power to the dc load, the first access voltage connected to the dc bus may cause the overcharge of the storage battery pack, and damage the storage battery pack. Therefore, in practice, in a current-limiting charging state, the photovoltaic power supply device cannot continuously supply power to the dc load, and when a first difference between the overload voltage and the dc bus voltage is less than or equal to a first preset value, the output voltage of the photovoltaic power supply device should be adjusted so that the photovoltaic power supply device does not supply power to the dc load any more, thereby avoiding that the storage battery pack is overcharged due to the addition of the first access voltage when the dc bus voltage approaches the overload voltage; when the first difference between the overload voltage and the dc bus voltage is greater than or equal to the first preset value, the photovoltaic power supply apparatus may supply power to the dc load, and the first access voltage may be any value of greater than the dc bus voltage and less than or equal to the dc bus voltage plus the first preset value, that is, the preset range is greater than the dc bus voltage and less than or equal to the dc bus voltage plus the first preset value.
For example, as shown in fig. 3, the overload voltage of a 48V battery pack may be 56.4V, the float voltage may be 54V, and the cutoff voltage may be 43.2V. The first preset value may be determined according to a difference between the first access voltage and the dc bus voltage in the floating charge state, and if the difference between the first access voltage and the dc bus voltage in the floating charge state is 0.3V, the first preset value may also be 0.3V. In the embodiment of the present invention, when the first difference between the overload voltage and the dc bus voltage is greater than or equal to 0.3V, the photovoltaic power supply apparatus may continuously supply power to the dc load, and the first access voltage may be any value greater than the dc bus voltage and less than or equal to the dc bus voltage plus the first preset value, so that when the dc bus voltage is 50V, the first access voltage may be any value from 50V to 50.3V.
1032. And if the difference value between the overload voltage and the direct current bus voltage is smaller than a first preset value, reducing the output voltage to enable the output current to be zero.
Specifically, as shown in fig. 3, when the dc power supply device charges the battery, the dc bus voltage gradually increases as the battery pack is charged. Since the battery pack has an overload voltage, the maximum dc bus voltage may be the overload voltage of the battery pack to avoid overcharging of the battery pack. Along with the charging of the storage battery pack, the terminal voltage of the storage battery pack gradually approaches the voltage of the direct-current bus, and the storage battery pack is basically charged at the moment.
When the current-limiting charging is completed, the voltage of the direct-current bus reaches the overload voltage, so that when the photovoltaic power supply device continues to output electric energy to the direct-current bus, the output voltage of the photovoltaic power supply device can cause the voltage of the direct-current bus to be larger than the overload voltage, and further, the storage battery pack is overcharged and damaged. Therefore, when the voltage of the direct current bus reaches the overload voltage, the output voltage of the photovoltaic power supply device is reduced, so that the photovoltaic power supply device does not output electric energy to the direct current bus any more, and the damage to the storage battery pack caused by the fact that the voltage of the direct current bus is larger than the overload voltage due to the output of the photovoltaic power supply device is avoided.
Of course, since the photovoltaic power supply device always has an access voltage greater than the dc bus voltage when supplying power to the dc load, the access voltage of the photovoltaic power supply device may cause the dc bus voltage to exceed the overload voltage. Therefore, in order to avoid the phenomenon that the storage battery pack is overcharged when the voltage of the direct current bus is close to the overload voltage, the output voltage of the photovoltaic power supply device can be controlled to be reduced, so that the photovoltaic power supply device does not supply power to the direct current load any more, namely when the difference value between the overload voltage and the voltage of the direct current bus is smaller than a first preset value, the photovoltaic power supply device does not supply power to the direct current load any more.
For example, the first preset value may be obtained through experiments according to the capacity of the battery pack, for example, a battery pack of 48V, and the overload voltage is 56.4V, and it may be determined through experiments that the first preset value may be 0.3V, that is, when the dc bus voltage is greater than or equal to 56.1V, and is less than or equal to 56.4V, the output voltage of the photovoltaic power supply device is controlled to decrease, and no power is supplied to the dc load.
Optionally, when the dc power supply device is in the voltage-limiting charging state, step 103 further includes:
1033. and increasing the output voltage by the first step length to enable the second access voltage corresponding to the output voltage to be larger than the direct current bus voltage.
And the second access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus.
Specifically, when the current-limiting charging of the storage battery pack is completed, because partial batteries possibly exist in the storage battery pack and the charging is not completely completed due to uneven charging, the direct-current power supply device enters a voltage-limiting charging state at the moment, the output voltage of the direct-current power supply device is gradually reduced to float charging voltage, and the direct-current bus voltage and the terminal voltage of the storage battery pack are gradually reduced to float charging voltage. At this time, because the voltage of the direct current bus is already smaller than the overload voltage, the output voltage of the photovoltaic power supply device can be controlled to increase, and power supply to the direct current load is continued.
As shown in fig. 3, in the voltage-limited charging state, because the dc bus voltage is gradually decreased, when the output voltage of the photovoltaic power supply device is controlled to increase and the second access voltage is increased, the output voltage of the photovoltaic power supply device can be gradually increased by the first adjustment step length, so that the output current is not zero.
1034. And if the second difference between the second access voltage and the direct current bus voltage is greater than a second preset value, reducing the output voltage by a second step length to enable the second difference to be smaller than the second preset value.
Specifically, in step 1033, after the output current of the photovoltaic power supply device is not zero by controlling the output voltage of the photovoltaic power supply device to increase by the first step length, if the difference between the second access voltage and the dc bus voltage is greater than the second preset value, the output voltage of the photovoltaic power supply device also needs to be decreased by the first step length, so that the second difference is smaller than the second preset value.
When the output voltage of the photovoltaic power supply device is increased according to the first step length, a second difference value of a second access voltage of the photovoltaic power supply device, which is accessed to the direct current bus, may be greater than a second preset value, for example, the voltage of the direct current bus is 54V, the second preset value is 0.3V, when the output voltage of the photovoltaic power supply device is adjusted according to the first step length, the second access voltage may be adjusted from 54V to 54.4V, and at this time, the second difference value is greater than the second preset value, so that the output voltage of the photovoltaic power supply device needs to be reduced according to the second step length, and the second difference value is smaller than the second preset value.
It should be noted that the first preset value may be the same as the second preset value, and the first step size is larger than the second step size.
An embodiment of the present invention provides a voltage control method, including: the photovoltaic power supply device acquires a first system parameter; the first system parameters comprise the output voltage of the photovoltaic power supply device and the direct current bus voltage; the photovoltaic power supply device determines the charging state of the direct current power supply device according to the voltage of the direct current bus; the charging state comprises current-limiting charging and voltage-limiting charging; the photovoltaic power supply device adjusts output voltage according to the direct current bus voltage and the charging state. According to the photovoltaic power supply system provided by the embodiment of the invention, when the direct current power supply device is in the uniform charging state, the output voltage of the photovoltaic power supply device can be adjusted in real time according to the voltage change of the direct current bus in the current-limiting charging state and the voltage-limiting charging state, so that the photovoltaic power supply device is ensured to supply power to a direct current load, and meanwhile, the overcharge of a storage battery pack is avoided.
As shown in fig. 5, an embodiment of the present invention further provides a photovoltaic power supply apparatus 20, including:
the communication module 201 is configured to obtain a dc bus voltage from a dc power supply device.
The obtaining module 202 is configured to obtain an output voltage of the photovoltaic power supply apparatus 20.
The processing module 203 is configured to determine a charging state of the dc power supply device according to the dc bus voltage obtained by the communication module 201; the charging states include current-limited charging and voltage-limited charging.
And an adjusting module 204, configured to adjust the output voltage obtained by the obtaining module 202 according to the dc bus voltage obtained by the communication module 201 and the charging state determined by the processing module 203.
Optionally, the communication module 201 is further configured to obtain an overload voltage of the battery pack from the dc power supply device.
The obtaining module 202 is further configured to obtain an output current of the photovoltaic power supply apparatus 20.
The adjusting module 204 is specifically configured to, when the dc power supply device is in a current-limiting charging state, adjust an output voltage if a first difference between an overload voltage and a dc bus voltage is greater than or equal to a first preset value, so that the output voltage is within a preset range corresponding to a first access voltage; the overload voltage is the maximum voltage charged by the storage battery pack, and the first access voltage is the voltage of the photovoltaic power supply device 20 accessed to the direct-current bus;
and if the difference value between the overload voltage and the direct current bus voltage is smaller than a first preset value, reducing the output voltage to enable the output current to be zero.
Optionally, the adjusting module 204 is further specifically configured to increase the output voltage by the first step when the dc power supply device is in the voltage-limiting charging state, so that a second access voltage corresponding to the output voltage is greater than the dc bus voltage; the second access voltage is a voltage of the photovoltaic power supply device 20 accessed to the dc bus.
Optionally, the adjusting module 204 is further specifically configured to decrease the output voltage by a second step length if a second difference between the second access voltage and the dc bus voltage is greater than a second preset value, so that the second difference is smaller than the second preset value.
The embodiment of the invention provides a photovoltaic power supply device, which comprises: the communication module is used for acquiring direct-current bus voltage from the direct-current power supply device; the acquisition module is used for acquiring the output voltage of the photovoltaic power supply device; the processing module is used for determining the charging state of the direct current power supply device according to the direct current bus voltage acquired by the communication module; the charging state comprises current-limiting charging and voltage-limiting charging; and the adjusting module is used for adjusting the output voltage obtained by the obtaining module according to the direct current bus voltage obtained by the communication module and the charging state determined by the processing module. When the direct current power supply device is in the uniform charging state, the photovoltaic power supply device provided by the embodiment of the invention can adjust the output voltage of the photovoltaic power supply device in real time according to the voltage change of the direct current bus in the current-limiting charging state and the voltage-limiting charging state, so that the photovoltaic power supply device is ensured to supply power to a direct current load, and meanwhile, the overcharge of a storage battery pack is avoided.
Through the above description of the embodiments, it is clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device may be divided into different functional modules to complete all or part of the above described functions.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the modules or units is only one logical function division, and there may be other division ways in actual implementation. For example, various elements or components may be combined or may be integrated into another device, or some features may be omitted, or not implemented. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form. Units described as separate parts may or may not be physically separate, and parts displayed as units may be one physical unit or a plurality of physical units, may be located in one place, or may be distributed to a plurality of different places. 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 integrated unit may be implemented in the form of hardware, or may also be implemented in the form of a software functional unit. The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or partially contributed to by the prior art, or all or part of the technical solutions may be embodied in the form of a software product, where the software product is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, or the like) or a processor (processor) 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: various media capable of storing program codes, such as a U disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (6)
1. A voltage control method is applied to a photovoltaic power supply system, the photovoltaic power supply system comprises a direct current bus, and a photovoltaic power supply device and a direct current power supply device which are connected with the direct current bus, and the method is characterized by comprising the following steps:
the photovoltaic power supply device acquires a first system parameter; the first system parameter comprises an output voltage of the photovoltaic power supply device and a direct current bus voltage;
the photovoltaic power supply device determines the charging state of the direct current power supply device according to the direct current bus voltage; the charging state comprises current-limiting charging and voltage-limiting charging;
the photovoltaic power supply device adjusts the output voltage according to the direct current bus voltage and the charging state;
the first system parameters further comprise the output current of the photovoltaic power supply device and the overload voltage of the storage battery pack; when the dc power supply device is in a current-limiting charging state, the adjusting, by the photovoltaic power supply device, the output voltage according to the dc bus voltage and the charging state includes:
if the first difference value between the overload voltage and the direct current bus voltage is larger than or equal to a first preset value, adjusting the output voltage to enable the output voltage to be in a preset range corresponding to a first access voltage; the overload voltage is the maximum voltage charged by the storage battery pack, and the first access voltage is the voltage of the photovoltaic power supply device accessed to the direct-current bus;
and if the difference value between the overload voltage and the direct current bus voltage is smaller than a first preset value, reducing the output voltage to enable the output current to be zero.
2. The voltage control method of claim 1, wherein when the dc power supply is in a voltage limited charging state, the adjusting the output voltage by the photovoltaic power supply according to the dc bus voltage and the charging state further comprises:
increasing the output voltage by a first step length to enable a second access voltage corresponding to the output voltage to be larger than the direct current bus voltage; the second access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus.
3. The voltage control method of claim 2, further comprising, after increasing the output voltage by the first step size:
and if the second difference value between the second access voltage and the direct current bus voltage is greater than a second preset value, reducing the output voltage by a second step length to enable the second difference value to be smaller than the second preset value.
4. A photovoltaic power supply apparatus, comprising:
the communication module is used for acquiring direct-current bus voltage from the direct-current power supply device;
the acquisition module is used for acquiring the output voltage of the photovoltaic power supply device;
the processing module is used for determining the charging state of the direct current power supply device according to the direct current bus voltage acquired by the communication module; the charging state comprises current-limiting charging and voltage-limiting charging;
the adjusting module is used for adjusting the output voltage acquired by the acquiring module according to the direct-current bus voltage acquired by the communication module and the charging state determined by the processing module;
the communication module is also used for acquiring the overload voltage of the storage battery pack from the direct-current power supply device;
the acquisition module is also used for acquiring the output current of the photovoltaic power supply device;
the adjusting module is specifically configured to, when the dc power supply device is in a current-limiting charging state, adjust the output voltage if a first difference between the overload voltage and the dc bus voltage is greater than or equal to a first preset value, so that the output voltage is within a preset range corresponding to a first access voltage; the overload voltage is the maximum voltage charged by the storage battery pack, and the first access voltage is the voltage of the photovoltaic power supply device accessed to the direct-current bus;
and if the difference value between the overload voltage and the direct current bus voltage is smaller than a first preset value, reducing the output voltage to enable the output current to be zero.
5. Photovoltaic power supply device according to claim 4,
the adjusting module is further specifically configured to increase the output voltage by a first step length when the dc power supply device is in a voltage-limiting charging state, so that a second access voltage corresponding to the output voltage is greater than the dc bus voltage; the second access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus.
6. The photovoltaic power supply device according to claim 5, wherein the adjusting module is further configured to decrease the output voltage by a second step length if a second difference between the second access voltage and the dc bus voltage is greater than a second preset value, so that the second difference is smaller than the second preset value.
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