CN110707679A - Voltage control method and photovoltaic power supply device and system - Google Patents
Voltage control method and photovoltaic power supply device and system Download PDFInfo
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- CN110707679A CN110707679A CN201911159747.0A CN201911159747A CN110707679A CN 110707679 A CN110707679 A CN 110707679A CN 201911159747 A CN201911159747 A CN 201911159747A CN 110707679 A CN110707679 A CN 110707679A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/10—Parallel operation of dc sources
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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
Abstract
The embodiment of the invention provides a voltage control method, a photovoltaic power supply device and a system, relates to the field of new energy, and is used for improving the energy utilization rate of the photovoltaic power supply device, and the method comprises the following steps: the photovoltaic power supply device acquires a first system parameter; the first system parameters comprise output voltage and output current of the photovoltaic power supply device, and line resistance and direct current bus voltage between the photovoltaic power supply device and a direct current bus; the photovoltaic power supply device determines an access voltage corresponding to the output voltage according to the output voltage, the output current and the resistance; the access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus; the photovoltaic power supply device adjusts output voltage according to the voltage of the direct current bus, so that the access voltage corresponding to the output voltage is greater than the voltage of the direct current bus and less than or equal to threshold voltage; the threshold voltage is determined based on the dc bus voltage and a predetermined floating voltage. The photovoltaic power supply device is used for improving the energy utilization rate 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 current photovoltaic power supply system 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 running state of the direct current power supply device can comprise a floating charge state, a discharge state and an even charge state according to the charge-discharge state of a storage battery pack in the photovoltaic power supply system. When the dc power supply device is in the uniform charging state, the dc bus voltage is affected by the power load of the dc load to generate fluctuation, and the output voltage of the photovoltaic power supply device is generally output in a static output manner.
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 improving the energy utilization rate of the photovoltaic power supply device.
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 output voltage and output current of the photovoltaic power supply device, and line resistance and direct current bus voltage between the photovoltaic power supply device and a direct current bus; the photovoltaic power supply device determines an access voltage corresponding to the output voltage according to the output voltage, the output current and the resistance; the access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus; the photovoltaic power supply device adjusts output voltage according to the voltage of the direct current bus, so that the access voltage corresponding to the output voltage is greater than the voltage of the direct current bus and less than or equal to threshold voltage; the threshold voltage is determined based on the dc bus voltage and a predetermined floating voltage.
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 and the output current of the photovoltaic power supply device and the line resistance between the photovoltaic power supply device and the direct current bus; the processing module is used for determining access voltage corresponding to the output voltage according to the output voltage, the output current and the resistance acquired by the acquisition module; the access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus; 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, so that the access voltage corresponding to the output voltage is greater than the direct current bus voltage and less than or equal to the threshold voltage; the threshold voltage is determined based on the dc bus voltage and a predetermined floating voltage.
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 a direct current load and a storage battery pack; 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 output voltage and output current of the photovoltaic power supply device, and line resistance and direct current bus voltage between the photovoltaic power supply device and a direct current bus; the photovoltaic power supply device determines an access voltage corresponding to the output voltage according to the output voltage, the output current and the resistance; the access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus; the photovoltaic power supply device adjusts output voltage according to the voltage of the direct current bus, so that the access voltage corresponding to the output voltage is greater than the voltage of the direct current bus and less than or equal to threshold voltage; the threshold voltage is determined based on the dc bus voltage and a predetermined floating voltage. According to the voltage control method provided by the embodiment of the invention, when the direct current power supply device is in a floating charge state, the output voltage of the photovoltaic power supply device is correspondingly adjusted according to the change of the direct current bus voltage, so that the access voltage corresponding to the output voltage is greater than the direct current bus voltage, the photovoltaic power supply device is ensured to continuously supply power to a direct current load, and the energy utilization rate of the photovoltaic power supply device is 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 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 flow chart of a voltage control method 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 practical experimental tests, it is found that the electric load of the direct current load in the photovoltaic power supply system has certain fluctuation, and the fluctuation can cause the change of the direct current bus current, so that the change of the direct current bus voltage is caused. The output voltage of the existing photovoltaic power supply device generally adopts a static output mode to supply power for the direct current load, and when the power load of the direct current load changes and the voltage of the direct current bus changes, if the output voltage of the photovoltaic power supply device is smaller than the changed voltage of the direct current bus, the photovoltaic power supply device cannot output the voltage, and further 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 pack 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 01, including an 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 013, as well as the operating turn-on voltage of the photovoltaic controller 013 and the line resistance between the photovoltaic controller 013 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.
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 floating state, and specifically includes:
101. the photovoltaic power supply device obtains a first system parameter.
The first system parameters comprise output voltage and output current of the photovoltaic power supply device, line resistance between the photovoltaic power supply device and the direct-current bus and 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 system, for example, the analysis module may acquire an output current and an output voltage of the photovoltaic power supply device, and a line resistance between the photovoltaic power supply device and the dc bus; the monitoring module can acquire the voltage of a direct current bus and the voltage of the terminal of the storage battery. 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 current and the output voltage of the photovoltaic controller are also the output current and the output voltage of the photovoltaic power supply apparatus.
102. The photovoltaic power supply device determines the access voltage corresponding to the output voltage according to the output voltage, the output current and the resistance.
The access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus.
Specifically, because there is a resistance in a line between the photovoltaic power supply device and the dc bus, when the photovoltaic power supply device transmits voltage to the dc bus, there is a partial voltage consumption, that is, there is a voltage drop between the photovoltaic power supply device and the dc bus. Since the current between the photovoltaic power supply device and the dc bus is the output current of the photovoltaic power supply device, the voltage drop is equal to the product of the output current of the photovoltaic power supply device and the above resistance. The input voltage can be determined by the difference between the output voltage of the photovoltaic power supply and the voltage drop.
For example, if the output voltage of the photovoltaic power supply device is 58V, the output current is 5A, and the resistance between the photovoltaic power supply device and the dc bus is 1 Ω, the voltage drop between the photovoltaic power supply device and the dc bus is 5A × 1 Ω — 5V, and the access voltage is 58V-5V — 53V.
103. The photovoltaic power supply device adjusts output voltage according to the voltage of the direct current bus, and the access voltage corresponding to the output voltage is larger than the voltage of the direct current bus and smaller than threshold voltage.
Wherein, the threshold voltage is determined according to the DC bus voltage and the preset floating voltage.
Specifically, when the dc power supply device is in a floating state, the storage battery pack is charged to saturation, and if the difference between the access voltage and the dc bus voltage is too large, the photovoltaic power supply device may continue to charge the storage battery pack, so that the storage battery pack is overcharged and damaged. Therefore, in order to ensure that the photovoltaic power supply device does not damage the storage battery pack while supplying power to the direct current load, the access voltage has a certain threshold value, for example, the access voltage is greater than the direct current bus voltage and is less than or equal to the threshold voltage. The threshold voltage is the voltage of the direct current bus plus a preset floating voltage, and if the preset floating voltage is 0.3V, the threshold voltage is the voltage of the direct current bus plus 0.3V.
And if the access voltage is greater than the threshold voltage, controlling the output voltage of the photovoltaic power supply device to be reduced by a second step length, so that the access voltage corresponding to the output voltage is correspondingly reduced, and the adjusted access voltage is greater than the direct-current bus voltage and less than or equal to the threshold voltage.
Optionally, the adjustment of the output voltage of the photovoltaic power supply device may also be performed according to a difference between the access voltage and the dc bus voltage, and if the difference between the access voltage and the dc bus voltage is greater than a second preset value, the output voltage of the photovoltaic power supply device is reduced, so that the access voltage corresponding to the output voltage of the photovoltaic power supply device is smaller than the second preset value.
For example, the preset floating voltage may be obtained through experiments according to the capacity of the secondary battery pack. For example, the floating charge voltage of the 48V storage battery pack is 54V, and the voltage of the direct current bus is kept at 54V when the direct current power supply device is in a floating state. Experiments can determine that when the difference between the access voltage and the dc bus voltage is greater than 0.3V, overcharge of the battery pack may be caused, that is, the second preset value is 0.3V. At this time, the access voltage may be any value between more than 54V and less than or equal to 54.3V.
When the value of the access voltage is greater than 54.3V, the second step length may be 0.05V, and the photovoltaic power supply device controls the output voltage to decrease by an adjustment step length of 0.05V, so that the access voltage is any value between greater than 54V and less than or equal to 54.3V. Of course, in practice, the preset floating voltage may be obtained through experiments according to different capacities of the battery pack, the present invention is not limited thereto, and the second step size of 0.05V is only an example, and can be set as required by those skilled in the art.
It is noted that the second preset value is the same as the preset floating voltage. The second preset value is not only for ensuring that the photovoltaic power supply device supplies power to the direct-current load, but also for determining through experiments that the output power of the photovoltaic power supply device is larger when the difference value between the access voltage and the direct-current bus voltage is smaller than or equal to the second preset value. Certainly, when the difference between the access voltage and the dc bus voltage is less than or equal to the second preset value, the photovoltaic controller may also perform Maximum Power Point Tracking (MPPT) on the access voltage when the difference between the access voltage and the dc bus voltage is less than the second preset value, so that the photovoltaic power supply device maintains maximum power output. Through the control, the photovoltaic power supply device can continuously supply power for the direct current load, can also provide input of maximum power for the direct current load, and improves the power supply efficiency.
Optionally, the first system parameter further includes a float voltage, and the float voltage is a terminal voltage of the storage battery pack in a float state. The floating charging voltage can be acquired by a monitoring module of a direct current power supply system, and storage battery packs with different capacities have different floating charging voltages.
Before step 103, as shown in fig. 3, the method further includes:
102A, a first difference between the dc bus voltage and the float voltage is determined.
Specifically, the floating charge voltage is a rated floating charge voltage of the storage battery pack, and in practice, when the dc bus supplies voltage to the storage battery pack to keep the storage battery pack in a floating charge state, the dc bus voltage may be greater than the rated floating charge voltage of the storage battery pack to keep the storage battery pack in the floating charge state. However, the first difference between the direct current bus voltage and the rated floating charge voltage of the storage battery pack cannot be overlarge, so that the storage battery pack is prevented from being overcharged when the direct current bus voltage is overlarge.
102B, if the first difference is larger than a first preset value, reducing the output voltage by a first step length to enable the first difference to be smaller than the first preset value.
Specifically, as can be seen from the step 103, when the access voltage and the dc bus voltage are greater than the first preset value, the battery pack may be overcharged. In practice, since the dc bus voltage may be higher than the float voltage by a certain range, before the corresponding access voltage is adjusted according to the output voltage of the photovoltaic power supply device, a first difference between the dc bus voltage and the float voltage should be determined, and when the first difference is greater than a first preset value, if the access voltage is greater than the dc bus voltage plus the preset float voltage, overcharging of the storage battery pack may be caused, that is, the difference between the access voltage and the float voltage should be less than or equal to the first preset value plus a second preset value, where if the first preset value is 0.2V, the second preset value is 0.3V, and the float voltage is 54V, the access voltage should be greater than 54.2V, and less than or equal to 54.5V; if the access voltage is larger than 54.5V, the output voltage is adjusted to enable the access voltage to be larger than 54.2V and smaller than or equal to 54.5V.
It should be noted that the first preset value and the second preset value are only exemplary, and when the first preset value is 0.2V, the first step length may be 0.1V. Of course, a person skilled in the art can also set the first preset value, the second preset value and the first step length according to actual requirements.
Optionally, the first system parameter further includes an input voltage and a starting voltage of the photovoltaic controller, and the input voltage and the starting voltage of the photovoltaic controller may be acquired by an analysis module of the photovoltaic power supply device.
After step 102B, further comprising:
and 102C, if the input voltage of the photovoltaic controller is greater than the starting voltage and the output current of the photovoltaic controller is zero, increasing the output voltage by a third step length to enable the output current to be greater than zero.
The starting voltage is the lowest voltage of the photovoltaic controller.
Specifically, when the input voltage of the photovoltaic controller is greater than the turn-on voltage, the photovoltaic controller normally operates, and the output current of the photovoltaic controller is zero, which may be caused by the fact that the access voltage corresponding to the output voltage of the photovoltaic controller is less than the dc bus voltage. Therefore, the output voltage of the photovoltaic controller can be increased, the corresponding access voltage is larger than the direct-current bus voltage, the output current of the photovoltaic controller is not zero, and the photovoltaic power supply device supplies power to the direct-current load.
Because the direct current power supply system is in a floating charge state, the third step length of the output voltage increase of the photovoltaic controller cannot be too large, so that the situation that the access voltage corresponding to the output voltage of the photovoltaic controller is too large due to the fact that the third step length is too large, and the storage battery pack is overcharged is avoided. For example, the third step length may be 0.08V.
Optionally, as shown in fig. 4, step 102C specifically includes:
102C1, increasing the output voltage by a third step length to make the access voltage corresponding to the output voltage greater than the direct current bus voltage.
And 102C2, determining a second difference value between the access voltage and the DC bus voltage, and if the second difference value is greater than the first preset value, reducing the output voltage by the first step length to enable the second difference value to be smaller than the first preset value.
Specifically, after the output voltage of the photovoltaic power supply device is adjusted to be greater than the dc bus voltage according to step 102C1 and the output current of the photovoltaic power supply device is not zero, it is further determined whether the access voltage corresponding to the output voltage of the photovoltaic power supply device is a value greater than the dc bus voltage and less than or equal to the threshold voltage. And when the second difference value is larger than the preset floating voltage, reducing the output voltage of the photovoltaic power supply device by the first step length to enable the second difference value to be smaller than or equal to the preset floating voltage. In essence, after the step 102C1 is executed, the step 102C2 is a loop of the step 103, that is, the output voltage of the photovoltaic power supply device is adjusted, so that the access voltage corresponding to the output voltage of the photovoltaic power supply device is greater than the dc bus voltage and less than or equal to the threshold voltage, so as to avoid the overcharge of the storage battery pack caused by the excessively large access voltage corresponding to the output voltage of the photovoltaic power supply device.
The voltage control method provided by the embodiment of the invention comprises the following steps: the photovoltaic power supply device acquires a first system parameter; the first system parameters comprise output voltage and output current of the photovoltaic power supply device, and line resistance and direct current bus voltage between the photovoltaic power supply device and a direct current bus; the photovoltaic power supply device determines an access voltage corresponding to the output voltage according to the output voltage, the output current and the resistance; the access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus; the photovoltaic power supply device adjusts output voltage according to the voltage of the direct current bus, so that the access voltage corresponding to the output voltage is greater than the voltage of the direct current bus and less than or equal to threshold voltage; the threshold voltage is determined based on the dc bus voltage and a predetermined floating voltage. According to the voltage control method provided by the embodiment of the invention, when the direct current power supply device is in a floating charge state, the output voltage of the photovoltaic power supply device is correspondingly adjusted according to the change of the direct current bus voltage, so that the access voltage corresponding to the output voltage is greater than the direct current bus voltage, the photovoltaic controller is ensured to continuously supply power to the direct current load, and the energy utilization rate of the photovoltaic power supply device is improved.
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 and an output current of the photovoltaic power supply device 20, and a line resistance between the photovoltaic power supply device and the dc bus.
The processing module 203 is configured to determine an access voltage corresponding to the output voltage according to the output voltage, the output current, and the resistance acquired by the acquisition module 202; the access voltage is the voltage of the photovoltaic power supply device 20 accessed to the direct current bus.
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, so that an access voltage corresponding to the output voltage is greater than the dc bus voltage and less than or equal to a threshold voltage; the threshold voltage is determined according to the direct current bus voltage and a preset floating voltage.
Optionally, the communication module 201 is further configured to obtain a float voltage from the dc power supply device; the float charge voltage is a terminal voltage when the battery pack is in a float charge state.
The adjusting module 204 is further configured to determine a first difference between the dc bus voltage and the float voltage; if the first difference is larger than the first preset value, the output voltage is reduced by the first step length, and the first difference is smaller than the first preset value.
Optionally, the obtaining module 202 is further configured to obtain an input voltage and a starting voltage of the photovoltaic controller; the starting voltage is the lowest voltage at which the photovoltaic controller works.
The adjusting module 204 is further configured to increase the output voltage by a third step length when the input voltage of the photovoltaic controller is greater than the turn-on voltage and the output current of the photovoltaic controller is zero, so that the output current is greater than zero.
Optionally, the adjusting module 204 is specifically configured to: increasing the output voltage by the third step length to enable the access voltage corresponding to the output voltage to be larger than the direct current bus voltage; and determining a second difference value between the access voltage and the direct-current bus voltage, and if the second difference value is greater than a second preset value, reducing the output voltage by the first step length to enable the second difference value to be smaller than the second preset value.
The photovoltaic power supply device provided by the embodiment of the invention 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 and the output current of the photovoltaic power supply device and the line resistance between the photovoltaic power supply device and the direct current bus; the processing module is used for determining access voltage corresponding to the output voltage according to the output voltage, the output current and the resistance acquired by the acquisition module; the access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus; 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, so that the access voltage corresponding to the output voltage is greater than the direct current bus voltage and less than or equal to the threshold voltage; the threshold voltage is determined based on the dc bus voltage and a predetermined floating voltage. According to the photovoltaic power supply device provided by the embodiment of the invention, when the direct current power supply device is in a floating charge state, the output voltage of the photovoltaic power supply device is correspondingly adjusted according to the change of the direct current bus voltage, so that the access voltage corresponding to the output voltage is greater than the direct current bus voltage, the photovoltaic power supply device is ensured to continuously supply power to a direct current load, and the energy utilization rate of the photovoltaic power supply device is improved.
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 can be realized in a form of hardware, and can also be realized in a 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 (10)
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 parameters comprise output voltage and output current of the photovoltaic power supply device, and line resistance and direct-current bus voltage between the photovoltaic power supply device and a direct-current bus;
the photovoltaic power supply device determines an access voltage corresponding to the output voltage according to the output voltage, the output current and the resistor; the access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus;
the photovoltaic power supply device adjusts the output voltage according to the direct current bus voltage, so that the access voltage corresponding to the output voltage is greater than the direct current bus voltage and less than or equal to a threshold voltage; the threshold voltage is determined according to the direct current bus voltage and a preset floating voltage.
2. The voltage control method of claim 1, wherein the first system parameter further comprises a float voltage, and the photovoltaic power supply apparatus adjusts the output voltage according to the dc bus voltage such that the input voltage corresponding to the output voltage is greater than the dc bus voltage and less than or equal to a threshold voltage, further comprising:
determining a first difference between the dc bus voltage and the float voltage; the floating charge voltage is the terminal voltage of the storage battery in a floating charge state;
and if the first difference is larger than a first preset value, reducing the output voltage by a first step length to enable the first difference to be smaller than the first preset value.
3. The voltage control method of claim 2, wherein the first system parameters further comprise an input voltage and a turn-on voltage of a photovoltaic controller, further comprising:
if the input voltage of the photovoltaic controller is greater than the starting voltage and the output current of the photovoltaic controller is zero, increasing the output voltage by a third step length to enable the output current to be greater than zero; the starting voltage is the lowest voltage of the photovoltaic controller.
4. The voltage control method of claim 3, wherein the increasing the output voltage in a third step comprises:
increasing the output voltage by a third step length to enable the access voltage corresponding to the output voltage to be larger than the direct current bus voltage;
and determining a second difference value between the access voltage and the direct current bus voltage, and if the second difference value is greater than a second preset value, reducing the output voltage by a first step length to enable the second difference value to be smaller than the second preset value.
5. 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 and the output current of the photovoltaic power supply device and the line resistance between the photovoltaic power supply device and the direct current bus;
the processing module is used for determining access voltage corresponding to the output voltage according to the output voltage, the output current and the resistance which are acquired by the acquisition module; the access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus;
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, so that the access voltage corresponding to the output voltage is greater than the direct current bus voltage and less than or equal to a threshold voltage; the threshold voltage is determined according to the direct current bus voltage and a preset floating voltage.
6. Photovoltaic power supply device according to claim 5,
the communication module is further used for acquiring a float charging voltage from the direct current power supply device; the floating charge voltage is the terminal voltage of the storage battery in a floating charge state;
the adjusting module is further configured to determine a first difference between the dc bus voltage and the float voltage; and if the first difference is larger than a first preset value, reducing the output voltage by a first step length to enable the first difference to be smaller than the first preset value.
7. Photovoltaic power supply device according to claim 6,
the acquisition module is also used for acquiring the input voltage and the starting voltage of the photovoltaic controller; the starting voltage is the lowest working voltage of the photovoltaic controller;
and the adjusting module is also used for increasing the output voltage by a third step length when the input voltage of the photovoltaic controller is greater than the starting voltage and the output current of the photovoltaic controller is zero, so that the output current is greater than zero.
8. The photovoltaic power supply device according to claim 7, wherein the adjusting module is specifically configured to:
increasing the output voltage by a third step length to enable the access voltage corresponding to the output voltage to be larger than the direct current bus voltage;
and determining a second difference value between the access voltage and the direct current bus voltage, and if the second difference value is greater than a second preset value, reducing the output voltage by a first step length to enable the second difference value to be smaller than the second preset value.
9. A photovoltaic power supply system, comprising: the system comprises a photovoltaic power supply device, a direct current bus and a storage battery pack;
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;
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.
10. The photovoltaic power supply system according to claim 9, wherein the photovoltaic power supply device comprises a photovoltaic panel, a photovoltaic controller and an analysis module, and the dc power supply device comprises a mains supply, a rectifying device and a monitoring module;
the photovoltaic panel is used for converting solar energy into electric energy and supplying power to the direct current load;
the photovoltaic controller is used for adjusting the output current and the output voltage of the photovoltaic panel to enable the photovoltaic power supply device to continuously supply power for the direct-current load;
the analysis module is used for acquiring a first system parameter; the first system parameter is a system parameter of the photovoltaic power supply system, and comprises an output voltage of a photovoltaic controller;
the analysis module is further configured to adjust an output voltage of the photovoltaic controller according to an operating state of the dc power supply device, so that the photovoltaic power supply device continuously supplies power to the dc load;
the commercial power is used for charging the storage battery pack and supplying power to the direct-current load;
the rectifying equipment is used for converting alternating current of the commercial power into direct current;
the monitoring module is used for acquiring a second system parameter; the second system parameter comprises a terminal voltage of the storage battery pack;
the monitoring module is further used for determining the running state of the direct current power supply device according to the terminal voltage of the storage battery pack.
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