CN110768359B - 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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- CN110768359B CN110768359B CN201911158475.2A CN201911158475A CN110768359B CN 110768359 B CN110768359 B CN 110768359B CN 201911158475 A CN201911158475 A CN 201911158475A CN 110768359 B CN110768359 B CN 110768359B
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- 238000002474 experimental method Methods 0.000 description 6
- 239000002699 waste material Substances 0.000 description 5
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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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- 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
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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 photovoltaic power supply system, relates to the field of new energy, and aims to improve the energy utilization rate of a photovoltaic energy power supply system. 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 DC bus voltage is related to the output voltage of the DC power supply device; determining the running state of the direct current power supply device according to the voltage of the direct current bus; and adjusting the output voltage of the photovoltaic power supply device according to the direct-current bus voltage and the running 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
With the development of the fifth generation (5G) mobile network, the energy consumption and environmental protection problems brought by the mobile network are becoming more serious. In order to solve the problems of energy consumption and environmental protection brought by the network, communication operators need to invest a large amount of operation cost.
In order to reduce the operation cost, photovoltaic energy has been widely used in the communication field as a renewable clean energy. The existing photovoltaic power supply device can be divided into a direct current-alternating current (DC-AC) type photovoltaic power supply device and a DC-DC type photovoltaic power supply device according to the difference of the photovoltaic controller, wherein the DC-DC type photovoltaic power supply device can supply power in a time-sharing manner through the photovoltaic controller and the DC power supply device and can also supply power with the DC power supply device.
When the photovoltaic power supply device outputs voltage through the photovoltaic controller, static voltage output is adopted, the capability of dynamically adjusting the output voltage is not realized, and when the voltage on the direct current bus fluctuates, the photovoltaic power supply device can possibly output voltage, so that photovoltaic energy waste is caused, and the energy utilization rate of the photovoltaic power supply device is low.
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 the output voltage of the photovoltaic power supply device and the direct current bus voltage; the DC bus voltage is related to the output voltage of the DC power supply device; determining the running state of the direct current power supply device according to the voltage of the direct current bus; and adjusting the output voltage of the photovoltaic power supply device according to the direct-current bus voltage and the running 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 DC bus voltage is related to the output voltage of the DC 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 running state of the direct current power supply device according to the direct current bus voltage acquired by the communication module; and the adjusting module is used for adjusting the output voltage of the photovoltaic power supply device according to the direct-current bus voltage acquired by the communication module and the running 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 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 the output voltage of the photovoltaic power supply device and the direct current bus voltage; the DC bus voltage is related to the output voltage of the DC power supply device; determining the running state of the direct current power supply device according to the voltage of the direct current bus; and adjusting the output voltage of the photovoltaic power supply device according to the direct-current bus voltage and the running 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 working state of the direct current power supply device and the direct current bus voltage, so that the photovoltaic power supply device always supplies power to a direct current load, and the photovoltaic energy waste caused by the change of the running state of the direct current power supply device 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 order to solve the problems of energy consumption and environmental protection caused by the rapid development of a mobile network, communication operators generally adopt a photovoltaic power supply device and a direct current power supply device to jointly supply power to communication equipment when establishing a communication station at present. In actual work, when the working state of the direct current power supply device changes or the power of a direct current load changes, the voltage of a direct current bus connected with the direct current power supply device changes, and the output of the photovoltaic power supply device is further influenced; meanwhile, the change of the illumination condition or the change of the environmental temperature can also cause the change of the output power of the photovoltaic power supply device, thereby influencing the output of the photovoltaic power supply device. The change of the dc bus voltage or the output of the photovoltaic power supply device may cause the photovoltaic power supply device to fail to output electric energy (if the output voltage of the photovoltaic power supply device is less than the dc bus voltage), thereby causing the waste of the photovoltaic energy.
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.
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-mentioned 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 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; the dc bus voltage is related to the output voltage of the dc power supply.
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, for example, the analysis module may acquire an input current, an input voltage, an output current, and an output voltage of the photovoltaic controller, and a resistance of a line between the photovoltaic controller and the dc bus; the monitoring module can acquire direct current bus voltage and terminal voltage of the storage battery pack, and the analysis module can acquire system parameters acquired by the monitoring module through communication with the monitoring module. The communication between the analysis module and the monitoring module may be a wired communication or a wireless communication, and the embodiment of the present invention is not limited thereto.
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. And the photovoltaic power supply device determines the running state of the direct current power supply device according to the voltage of the direct current bus.
Specifically, the operation state of the dc power supply device includes a floating charge state, a uniform charge state and a discharge state, and the uniform charge state includes a current-limiting charge state and a voltage-limiting charge state. Because the direct current supply device is in different running states, the direct current bus has different voltage values, so the monitoring module can determine the running state of the direct current supply device according to the voltage of the direct current bus.
For example, the monitoring module may determine the operation state of the dc power supply device with reference to the dc bus voltage shown in fig. 3, such as that the dc power supply device is in a float state and the dc bus voltage is maintained at a float voltage during a time period T1; in a time period T2, the direct current power supply device is in a discharging state, and the direct current bus voltage is gradually reduced from the float charging voltage to a cut-off voltage; in a time period T3, 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 time period T4, the direct current power supply device is in a voltage-limiting charging state, and the voltage of the direct current bus is gradually reduced from cut-off voltage to float charging voltage; during the time period T4, the dc power supply again enters the float state and the dc bus voltage remains at the float voltage. Referring to fig. 3, the monitoring module may determine the operation state of the dc power supply device according to the change of the dc bus voltage.
The floating charge voltage is a voltage value for keeping a floating charge state after the storage battery pack finishes charging; the overload voltage is the maximum voltage for charging the storage battery pack, and when the voltage of the direct-current bus exceeds the overload voltage, the storage battery pack is possibly overcharged, so that the storage battery pack is damaged; the cut-off voltage is the lowest voltage of the battery pack discharge, and when the terminal voltage of the battery pack decreases to the cut-off voltage, if the battery pack continues to discharge, the battery pack may be damaged. When the direct current power supply device is in a uniform charging state, the terminal voltage of the storage battery pack changes along with the voltage of the direct current bus; when the direct current power supply device is in a discharging state, the voltage of a direct current bus changes along with the terminal voltage of the storage battery pack; when the direct current power supply device is in a floating charge state, the voltage of the direct current bus is kept at a floating charge voltage; therefore, the monitoring module can determine the running state of the direct current power supply device according to the direct current bus voltage. It should be noted that the overload voltage, the float voltage and the cut-off voltage can be acquired by the monitoring module, and the storage battery packs with different capacities have different overload voltages, float voltages and cut-off voltages.
The correlation between the dc bus voltage and the output voltage of the dc power supply device means that the dc bus voltage varies with the output voltage of the dc power supply device when the dc power supply device is in the floating charge state and the uniform charge state.
103. The photovoltaic power supply device adjusts output voltage according to the voltage of the direct current bus and the running state.
Specifically, when the dc power supply device is in different operating states, the dc bus voltage will change accordingly. Therefore, in order to enable the photovoltaic power supply device to continuously supply power to the direct current load, the output voltage of the photovoltaic power supply device can be controlled to be correspondingly adjusted according to the direct current bus voltage and the running state of the direct current power supply device.
Optionally, as shown in fig. 4, when the dc power supply device is in the float charging state, step 103 may include:
1031. and if the output current of the photovoltaic power supply device is zero, adjusting the output voltage of the photovoltaic power supply device to increase, so that the photovoltaic power supply device transmits current to the direct current bus.
Specifically, when the input current of the photovoltaic controller is not zero, the input voltage is greater than the turn-on voltage of the photovoltaic controller, and the output current of the photovoltaic controller is zero, the voltage of the photovoltaic controller connected to the dc bus may be smaller than the voltage of the dc bus. Therefore, the output voltage of the photovoltaic power supply device can be increased, so that the first access voltage is larger than the voltage of the direct current bus, and the photovoltaic power supply device can transmit current to the direct current bus. The first access voltage is the voltage of the photovoltaic power supply device accessing the direct current bus, namely the voltage of the photovoltaic controller accessing the direct current bus.
Because the output power of the photovoltaic power supply device is unchanged under the condition that the illumination condition is unchanged, and the first access voltage is the voltage of the photovoltaic controller accessed to the direct current bus, when the output voltage of the photovoltaic controller is increased, the output current of the photovoltaic controller is reduced. Accordingly, the difference between the output voltage of the photovoltaic controller and the voltage drop increases, i.e. the first access voltage increases. Therefore, the output voltage of the photovoltaic controller can be adjusted to enable the first access voltage to be larger than the direct-current bus voltage, and the photovoltaic power supply device can supply power to the direct-current load.
1032. If the output current of the photovoltaic power supply device is not zero, the output voltage of the photovoltaic power supply device is adjusted, and the first access voltage corresponding to the output voltage of the photovoltaic power supply device is in a first range.
The first range is used for avoiding overload charging of the storage battery pack caused by overlarge first access voltage in a floating charging state.
Specifically, the output current of the photovoltaic power supply device is not zero, and may be obtained after the adjustment in step 1031, or may be collected and determined by the analysis module without the adjustment in step 1031. Because the storage battery pack is charged to saturation when the direct current power supply device is in a floating state, if the difference value between the first access voltage and the direct current bus voltage is too large, the photovoltaic power supply device can 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 supplies power to the direct-current load without damaging the storage battery pack, the first access voltage should be kept within a first range, the lower limit of the first range may be the direct-current bus voltage, the upper limit may be the direct-current bus voltage plus a preset value, and the first access voltage cannot be equal to the lower limit of the first range.
For example, the first range may be obtained through experiments according to the capacity of the 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 first access voltage and the direct-current bus voltage is greater than 0.3V, overcharge of the storage battery pack can be caused, namely the preset value is 0.3V. At this time, the first range may be 54V to 54.3V, and the first access voltage is any value between greater than 54V and less than or equal to 54.3V. In practice, the first range may be obtained by different experiments on the capacity of the battery pack, and the present invention is not limited thereto.
It should be noted that the preset value is not only to ensure that the photovoltaic power supply apparatus supplies power to the dc load, but also to determine, through experiments, that when a difference between the first access voltage and the dc bus voltage is smaller than or equal to the preset value, the output power of the photovoltaic power supply apparatus is larger. Certainly, when the difference between the first access voltage and the dc bus voltage is less than or equal to the preset value, the photovoltaic controller may further perform Maximum Power Point Tracking (MPPT) on the first access voltage within the first range, 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, as shown in fig. 4, when the dc power supply device is in the charge balancing state, step 103 may further include:
1033. when the direct current power supply device is in a current-limiting charging state, if the direct current bus voltage is in a second range, the output voltage of the photovoltaic power supply device is controlled to be reduced, and the output current of the photovoltaic power supply device is enabled to be zero.
Specifically, as shown in fig. 3, when the dc power supply device charges the storage battery, the dc bus voltage gradually increases along with the completion progress of the charging of the storage battery pack. 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 voltage of the direct current bus is in a second range, the photovoltaic power supply device does not supply power to the direct current load any more.
For example, the second range 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 second range may be 56.1V to 56.4V, that is, when the dc bus voltage is greater than or equal to 56.1V and less than or equal to 56.4V, the output voltage of the photovoltaic power supply device is controlled to be reduced, and no power is supplied to the dc load.
1034. When the direct current power supply device is in a voltage-limiting charging state, the output voltage of the photovoltaic power supply device is increased by a first adjustment step length, so that the output current of the photovoltaic power supply device is not zero.
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.
1035. And if the difference value between the second access voltage corresponding to the output voltage of the photovoltaic power supply device after adjustment and the direct-current bus voltage is larger than the preset value, reducing the output voltage of the whole photovoltaic power supply device by a second adjustment step length to enable the second access voltage to be in a first range.
The second access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus, and the first adjustment step length is larger than the second adjustment step length.
Specifically, in step 1034, 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 adjustment step length, if the difference between the second access voltage and the dc bus voltage is greater than the preset value, the output voltage of the photovoltaic power supply device needs to be decreased by the second adjustment step length, so that the second access voltage is in the first range. When the output voltage of the photovoltaic power supply device is increased according to the first adjustment step length, the second access voltage of the photovoltaic power supply device to the direct current bus may jump the first range, that is, the second access voltage is directly adjusted from the minimum value smaller than the first range to the maximum value larger than the first range, for example, the first range is 54V to 54.3V, and the second access voltage may be adjusted from 54V to 54.4V. Therefore, when the difference value between the second access voltage and the direct-current bus voltage is larger than the preset value, the output voltage of the photovoltaic controller can be controlled to be reduced by a second adjustment step length, and the second access voltage is enabled to be in the first range.
Optionally, when the dc power supply device is in a discharging state, the dc power supply device stops supplying power to the dc load, the storage battery pack and the photovoltaic power supply device supply power to the dc load together, the storage battery pack starts to discharge, the terminal voltage of the storage battery pack gradually decreases along with the discharge, and the dc bus voltage also gradually decreases along with the terminal voltage of the storage battery pack. Therefore, the output voltage of the photovoltaic power supply device can be kept unchanged, and the photovoltaic power supply device can continuously supply power for the direct-current load.
It should be noted that, in the embodiment of the present invention, the photovoltaic controller has an operation starting voltage, and the photovoltaic controller does not operate when the input voltage of the photovoltaic controller is less than the operation starting voltage, so that the implementation of the above control method needs to ensure that the input voltage of the photovoltaic controller is greater than the operation starting voltage of the photovoltaic controller.
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 the output voltage of the photovoltaic power supply device and the direct current bus voltage; the DC bus voltage is related to the output voltage of the DC power supply device; determining the running state of the direct current power supply device according to the voltage of the direct current bus; and adjusting the output voltage of the photovoltaic power supply device according to the direct-current bus voltage and the running state. The photovoltaic power supply device provided by the embodiment of the invention can adjust the output voltage of the photovoltaic controller in real time according to the working state of the direct current power supply device and the direct current bus voltage, so that the photovoltaic power supply device always supplies power to a direct current load, and the photovoltaic energy waste caused by the change of the running state of the direct current power supply device is avoided.
As shown in fig. 5, an embodiment of the present invention further provides a photovoltaic power supply apparatus 20, including:
a communication module 201, configured to obtain a dc bus voltage from a dc power supply device; the dc bus voltage is related to the output voltage of the dc power supply.
The obtaining module 202 is configured to obtain an output voltage of the photovoltaic power supply apparatus.
And the processing module 203 is configured to determine an operating state of the dc power supply device according to the dc bus voltage obtained by the communication module 201.
And an adjusting module 204, configured to adjust the output voltage of the photovoltaic power supply apparatus obtained by the obtaining module 202 according to the dc bus voltage obtained by the communication module 201 and the operating state determined by the processing module 203.
Optionally, the operation state of the dc power supply device includes a float charging state.
The obtaining module 202 is further configured to obtain an output current of the photovoltaic power supply apparatus;
the adjusting module 204 is specifically configured to: when the processing module 203 determines that the dc power supply device is in the floating charge state, if the output current of the photovoltaic power supply device 20 is zero, the output voltage of the photovoltaic power supply device 20 is adjusted to increase, so that the photovoltaic power supply device 20 transmits current to the dc bus;
if the output current of the photovoltaic power supply device 20 is not zero, adjusting the output voltage of the photovoltaic power supply device 20 to make the first access voltage corresponding to the output voltage of the photovoltaic power supply device 20 in a first range; the first connection voltage is a voltage of the photovoltaic power supply device 20 connected to the dc bus.
Optionally, the operation state of the dc power supply device includes a charge equalization state, and the charge equalization state includes current-limiting charging and voltage-limiting charging.
The adjusting module 204 is specifically configured to: when the processing module 203 determines that the dc power supply device is in the current-limiting charging state, if the dc bus voltage is in the second range, the output voltage of the photovoltaic power supply device 20 is controlled to decrease, so that the output current of the photovoltaic power supply device 20 is zero.
The adjustment module is further specifically configured to: when the processing module 203 determines that the dc power supply device is in the voltage-limiting charging state, the output voltage of the photovoltaic power supply device 20 is increased by a first adjustment step length, so that the output current of the photovoltaic power supply device 20 is not zero;
if the difference value between the second access voltage corresponding to the adjusted output voltage of the photovoltaic power supply device 20 and the direct-current bus voltage is greater than the preset value, reducing the output voltage of the entire photovoltaic power supply device 20 by a second adjustment step length to enable the second access voltage to be within a first range; the second access voltage is a voltage of the photovoltaic power supply device 20 accessed to the direct current bus, and the first adjustment step length is larger than the second adjustment step length.
Optionally, when the dc power supply device is in a discharging state, the dc power supply device stops supplying power to the dc load, and the storage battery pack and the photovoltaic power supply device 20 supply power to the dc load together. The storage battery pack starts to discharge, the terminal voltage of the storage battery pack is gradually reduced along with the discharge, and the direct-current bus voltage is also gradually reduced along with the terminal voltage of the storage battery pack. Therefore, the output voltage of the photovoltaic power supply device 20 can be kept unchanged, and the photovoltaic power supply device 20 can continuously supply power for the direct-current load.
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 DC bus voltage is related to the output voltage of the DC 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 running state of the direct current power supply device according to the direct current bus voltage acquired by the communication module; and the adjusting module is used for adjusting the output voltage of the photovoltaic power supply device according to the direct-current bus voltage acquired by the communication module and the running state determined by the processing module. The photovoltaic power supply device provided by the embodiment of the invention can adjust the output voltage of the photovoltaic controller in real time according to the working state of the direct current power supply device and the direct current bus voltage, so that the photovoltaic power supply device always supplies power to a direct current load, and the photovoltaic energy waste caused by the change of the running state of the direct current power supply device 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 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 parameter comprises the output voltage of the photovoltaic power supply device and the direct current bus voltage; the direct current bus voltage is related to the output voltage of the direct current power supply device;
the photovoltaic power supply device determines the running state of the direct current power supply device according to the direct current bus voltage; the running states of the direct current power supply device comprise a floating charge state, a uniform charge state and a discharge state; the charge equalizing state comprises current-limiting charging and voltage-limiting charging;
and the photovoltaic power supply device adjusts the output voltage of the photovoltaic power supply device according to the direct current bus voltage and the running state.
2. The voltage control method of claim 1, wherein the operating condition comprises a float state, the first system parameter further comprising an output current of a photovoltaic power supply; the photovoltaic power supply device adjusting the output voltage of the photovoltaic power supply device according to the direct current bus voltage and the operation state comprises the following steps:
when the direct current power supply device is in a floating charge state, if the output current of the photovoltaic power supply device is zero, adjusting the output voltage of the photovoltaic power supply device to increase, so that the photovoltaic power supply device transmits current to a direct current bus;
if the output current of the photovoltaic power supply device is not zero, adjusting the output voltage of the photovoltaic power supply device to enable a first access voltage corresponding to the output voltage of the photovoltaic power supply device to be in a first range; the first access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus; the lower limit of the first range is the voltage of the direct current bus, the upper limit is the voltage of the direct current bus plus a preset value, and the first access voltage cannot be equal to the lower limit of the first range.
3. The voltage control method of claim 1, wherein the operating state comprises a charge equalization state comprising current limited charging and voltage limited charging; the photovoltaic power supply device adjusting the output voltage of the photovoltaic power supply device according to the direct current bus voltage and the operation state comprises the following steps:
when the direct current power supply device is in the current-limiting charging state, if the direct current bus voltage is in a second range, controlling the output voltage of the photovoltaic power supply device to be reduced, and enabling the output current of the photovoltaic power supply device to be zero; the upper limit of the second range is the overload voltage and the lower limit is the overload voltage minus a preset value.
4. The voltage control method according to claim 3, further comprising:
when the direct current power supply device is in the voltage-limiting charging state, increasing the output voltage of the photovoltaic power supply device by a first adjustment step length to enable the output current of the photovoltaic power supply device not to be zero;
if the difference value between the second access voltage corresponding to the adjusted output voltage of the photovoltaic power supply device and the direct-current bus voltage is larger than a preset value, reducing the output voltage of the entire photovoltaic power supply device by a second adjustment step length to enable the second access voltage to be in a first range; the second access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus, and the first adjustment step length is larger than the second adjustment step length.
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 direct current bus voltage is related to the output voltage of 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 running state of the direct current power supply device according to the direct current bus voltage acquired by the communication module; the running states of the direct current power supply device comprise a floating charge state, a uniform charge state and a discharge state; the charge equalizing state comprises current-limiting charging and voltage-limiting charging;
and the adjusting module is used for adjusting the output voltage of the photovoltaic power supply device acquired by the acquiring module according to the direct-current bus voltage acquired by the communication module and the running state determined by the processing module.
6. The photovoltaic power supply of claim 5, wherein the operating state comprises a float state;
the acquisition module is further used for acquiring the output current of the photovoltaic power supply device;
the adjustment module is specifically configured to: when the processing module determines that the direct current power supply device is in a floating charge state, if the output current of the photovoltaic power supply device is zero, adjusting the output voltage of the photovoltaic power supply device to increase, so that the photovoltaic power supply device transmits current to a direct current bus;
if the output current of the photovoltaic power supply device is not zero, adjusting the output voltage of the photovoltaic power supply device to enable a first access voltage corresponding to the output voltage of the photovoltaic power supply device to be in a first range; the first access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus.
7. The photovoltaic power supply device according to claim 5, wherein the operating state comprises a charge equalization state, the charge equalization state comprising current limited charging and voltage limited charging; the adjustment module is specifically configured to:
when the processing module determines that the direct current power supply device is in the current-limiting charging state, if the direct current bus voltage is in a second range, the output voltage of the photovoltaic power supply device is controlled to be reduced, and the output current of the photovoltaic power supply device is enabled to be zero.
8. The photovoltaic power supply apparatus according to claim 7, wherein the adjusting module is further specifically configured to:
when the processing module determines that the direct current power supply device is in the voltage-limiting charging state, increasing the output voltage of the photovoltaic power supply device by a first adjustment step length to enable the output current of the photovoltaic power supply device not to be zero;
if the difference value between the second access voltage corresponding to the adjusted output voltage of the photovoltaic power supply device and the direct-current bus voltage is larger than a preset value, reducing the output voltage of the entire photovoltaic power supply device by a second adjustment step length to enable the second access voltage to be in a first range; the second access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus, and the first adjustment step length is larger than the second adjustment step length.
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;
the photovoltaic power supply device comprises a photovoltaic controller and an analysis module, and the direct current power supply device comprises a monitoring module;
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 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 running states of the direct current power supply device comprise a floating charge state, a uniform charge state and a discharge state; the charge equalizing state comprises current-limiting charging and voltage-limiting charging;
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.
10. The photovoltaic power system of claim 9, wherein the photovoltaic power unit further comprises a photovoltaic panel, the dc power unit further comprises utility power and rectifying equipment;
the photovoltaic panel is used for converting solar energy into electric energy and supplying power to 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 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 includes a terminal voltage of the battery pack.
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| CN102545299B (en) * | 2010-12-08 | 2014-04-09 | 中国电信股份有限公司 | Solar photovoltaic power generation system and power supply method for communication |
| US9906038B2 (en) * | 2015-01-29 | 2018-02-27 | Cyboenergy, Inc. | Smart renewable power generation system with grid and DC source flexibility |
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| CN205792438U (en) * | 2016-06-30 | 2016-12-07 | 扬州华鼎电器有限公司 | A kind of photovoltaic module string power optimized system |
| CN109560539A (en) * | 2018-10-26 | 2019-04-02 | 珠海瓦特电力设备有限公司 | A kind of method, circuit and the device of photovoltaic direct-furnish DC power system power distribution |
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