CN111064263B - Voltage control method, photovoltaic power supply device and system - Google Patents

Abstract

Embodiments of the present invention provide a voltage control method, a photovoltaic power supply device, and a system, which relate to the field of new energy and are used to improve the energy utilization rate of a photovoltaic power supply system. The method includes: the photovoltaic power supply device obtains the first system parameter; the first system parameter Including the output voltage of the photovoltaic power supply device and the DC bus voltage; the photovoltaic power supply device determines the charging status of the DC power supply device according to the DC bus voltage; the charging status includes current-limited charging and voltage-limited charging; the photovoltaic power supply device adjusts the output according to the DC bus voltage and charging status Voltage. The invention is used for dynamically adjusting the output voltage of a photovoltaic power supply device.

Description

Voltage control method, photovoltaic power supply device and system

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 system.

Background technique

The current photovoltaic power supply system includes a photovoltaic power supply device, a DC power supply device and a DC bus connected thereto. The photovoltaic power supply device and the DC power supply device usually provide time-sharing power supply. According to the charge and discharge state of the battery pack in the photovoltaic power supply system, the operating state of the DC power supply device may include a floating charge state, a discharge state and an equal charge state. When the DC power supply device is in the state of equal charging, the DC bus voltage changes in real time, and the output voltage of the photovoltaic power supply device is generally output in a static output mode. Therefore, when the DC bus voltage becomes larger, the output voltage of the photovoltaic power supply device may be lower than the DC The bus voltage causes the power of the photovoltaic power supply device to fail to output, resulting in waste of photovoltaic energy.

Contents of the invention

Embodiments of the present invention provide a voltage control method, a photovoltaic power supply device, and a system for dynamically adjusting the output voltage of the photovoltaic power supply system and improving the energy utilization rate of the photovoltaic power supply system.

In order to achieve the above object, embodiments of the present invention adopt the following technical solutions:

In the first aspect, a voltage control method is provided, which is applied to a photovoltaic power supply system. The photovoltaic power supply system includes a DC bus, a photovoltaic power supply device connected to the DC bus, and a DC power supply device. The method includes: the photovoltaic power supply device acquires a first system parameter; The first system parameter includes the output voltage of the photovoltaic power supply device and the DC bus voltage; the photovoltaic power supply device determines the charging state of the DC power supply device according to the DC bus voltage; the charging state includes current-limited charging and voltage-limited charging; state of charge to adjust the output voltage.

In the second aspect, a photovoltaic power supply device is provided, including: a communication module, used to obtain the DC bus voltage from the DC power supply device; an acquisition module, used to obtain the output voltage of the photovoltaic power supply device; The DC bus voltage determines the charging state of the DC power supply device; the charging state includes current-limited charging and voltage-limited charging; the adjustment module is used to adjust the output voltage obtained by the acquisition module according to the DC bus voltage obtained by the communication module and the charging state determined by the processing module.

In the third aspect, a photovoltaic power supply system is provided, including: a photovoltaic power supply device for converting solar energy into electric energy and supplying power to a DC load; a DC power supply device for supplying power to a DC load and charging a battery pack; a DC bus , used to transmit the electric energy of the photovoltaic power supply device and the DC power supply device to the battery pack and the DC load; the battery pack is used for energy storage, and supplies power to the DC load when the DC power supply device is out of power.

Embodiments of the present invention provide a voltage control method, a photovoltaic power supply device, and a system. The method includes: the photovoltaic power supply device acquires first system parameters; the first system parameters include the output voltage of the photovoltaic power supply device and the DC bus voltage; the photovoltaic power supply device according to The DC bus voltage determines the charging status of the DC power supply device; the charging status includes current-limited charging and voltage-limited charging; the photovoltaic power supply device adjusts the output voltage according to the DC bus voltage and charging status. The photovoltaic power supply system provided by the embodiments of the present invention can adjust the output voltage of the photovoltaic power supply device in real time according to the DC bus voltage changes in the current-limited charging state and voltage-limited charging state when the DC power supply device is in the equal charge state, ensuring that the photovoltaic power supply device While supplying power to DC loads, avoid overcharging of the battery pack.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic structural diagram of a photovoltaic power supply system provided by an embodiment of the present invention;

FIG. 2 is a schematic flow diagram of a voltage control method provided by an embodiment of the present invention;

Fig. 3 is a schematic diagram of a DC bus voltage in different operating states of a DC power supply device provided by an embodiment of the present invention;

FIG. 4 is a second schematic flow diagram of a voltage control method provided by an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a photovoltaic power supply device provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to 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 for example, illustration or illustration. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present invention shall not be construed as being more preferred or more advantageous than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete manner.

In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as "first" and "second" are used to distinguish the same or similar items with basically the same functions and functions. A skilled person can understand that words such as "first" and "second" do not limit the quantity and execution order.

In the existing photovoltaic power supply system, the output voltage of the photovoltaic power supply device remains a static output. When the DC power supply device is in the equal charge state, the DC bus voltage changes in real time according to the charging progress of the battery pack. Therefore, if the photovoltaic power supply device maintains a static output, the access voltage of the photovoltaic power supply device to the DC bus may be lower than the DC bus voltage, making the photovoltaic The power supply device cannot supply power to the DC load, resulting in waste of photovoltaic energy.

In view of the above problems, as shown in FIG. 1 , an embodiment of the present invention provides a photovoltaic power supply system, including: a photovoltaic power supply device 01 , a DC power supply device 02 , a DC bus 03 , a battery pack 04 and a DC load 05 .

Referring to Figure 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 the DC bus 03, and the input end of the battery pack 04 and the input end of the DC load 05 are connected to the DC bus 03, the photovoltaic power supply device 01 and DC power supply device 02 transmit electric energy to battery pack 04 and DC load 05 through DC bus 03 . It should be noted that the voltages everywhere on the DC bus 03 are the same.

Among them, the photovoltaic power supply device 01 is used to convert solar energy into electric energy and supply power to a DC load 05 .

The DC power supply device 02 is used for supplying power to the DC load 05 and charging the battery pack 04 .

The DC bus 03 is used to transmit the electric energy of the photovoltaic power supply device 01 and the DC power supply device 02 to the battery pack 04 and the DC load 05 .

The battery pack 04 is used for energy storage, and for supplying power to the DC load 05 when the DC power supply device 02 is powered off.

Specifically, the power generated by the photovoltaic power supply device 01 is less than the power of the DC load 05, and the photovoltaic power supply device 01 cannot supply power to the DC load 05 alone. The photovoltaic power supply device 01 can supply power to the DC load 05 together with the DC power supply device 02 or the battery pack 04. It is also possible to supply power to the DC load 05 only through the DC power supply device 02 .

Optionally, the photovoltaic power supply device 01 includes a photovoltaic panel 011 , a photovoltaic controller 012 and an analysis module 013 , and the DC power supply device 02 includes a mains 021 , a rectifying device 022 and a monitoring module 023 .

The photovoltaic panel 011 is used to convert solar energy into electrical energy and supply power to the DC load 05.

The photovoltaic controller 012 is used to adjust the output current and output voltage of the photovoltaic panel 011 so that the photovoltaic power supply device 01 can continuously supply power to the DC load 05 while outputting the voltage at the maximum power point.

An analysis module 013, configured to obtain a first system parameter; the first system parameter is a system parameter of the photovoltaic power supply system, including the output voltage of the photovoltaic controller 012;

The analysis module 013 is also used to adjust the output voltage of the photovoltaic controller 012 according to the operating state of the DC power supply device 02 , so that the photovoltaic power supply device 01 can continuously supply power to the DC load 05 .

Specifically, the first system parameters also include: the input current, input voltage and output current of the photovoltaic controller 012 , and the working start voltage of the photovoltaic controller 012 and the line resistance between the photovoltaic controller 012 and the DC bus 03 .

The mains power 021 is used to charge the battery pack 04 and supply power to the DC load 05 .

The rectifying device 022 is used to convert the alternating current of the mains 021 into direct current, and provide charging voltage for the battery pack 04 .

A monitoring module 023, configured to obtain a second system parameter; the second system parameter includes a DC bus voltage and a terminal voltage of the battery pack 04;

The monitoring module 023 is further configured to determine the operating state of the DC power supply device 02 according to the terminal voltage of the battery pack 04 .

Optionally, since the DC bus 03 has different voltage values when the DC power supply device 02 is in different operating states, the monitoring module 023 can determine the operating status of the DC power supply device 02 according to the DC bus voltage.

It should be noted that the above-mentioned first system parameter may include the 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, here When , the analysis module 013 can obtain the parameter information collected by the monitoring module 023 through communication with the monitoring module 023 .

According to the above photovoltaic power supply system, as shown in Figure 2, an embodiment of the present invention provides a voltage control method, which is applied to a photovoltaic power supply system. The photovoltaic power supply system includes a DC bus, a photovoltaic power supply device connected to the DC bus, and a DC power supply device. The method is used to dynamically adjust the output voltage of the photovoltaic power supply device when the DC power supply device is in the equal charge state, specifically including:

101. The photovoltaic power supply device acquires a first system parameter.

Wherein, the first system parameter includes the output voltage of the photovoltaic power supply device and the DC bus voltage.

Specifically, the first system parameter can be collected by the analysis module of the photovoltaic power supply device and the monitoring module of the DC power supply device. For example, the analysis module can collect the output voltage of the photovoltaic power supply device, and the monitoring module can collect the DC bus voltage. The analysis module can obtain the system parameters collected by the monitoring module through communication with the monitoring module. The communication between the analysis module and the monitoring module can be wired communication or wireless communication, which is not limited in this embodiment of the present invention.

It should be noted that, in the embodiment of the present invention, the output voltage of the photovoltaic power supply device is also the output voltage of the photovoltaic controller.

102. Determine the charging state of the DC power supply device according to the DC bus voltage.

Wherein, the charging state includes current-limited charging and voltage-limited charging.

Specifically, because the equalizing charging state includes current-limiting charging and voltage-limiting charging, and the DC bus voltage has different voltage values in different charging states, so when the DC power supply device is in different charging states, the output voltage of the photovoltaic power supply device should be corresponding adjustment. Since the DC bus voltage is lower than the floating charge voltage of the storage battery when the DC power supply device is in the equal charge state, and the changes in the DC bus voltage during the current-limited charging and voltage-limited charging stages are different, the DC power supply device can be determined according to the change in the DC bus voltage. charging. The float charge voltage is the terminal voltage when the battery pack maintains the float charge state.

Exemplarily, the charging state of the DC power supply device can be determined by the monitoring module of the DC power supply device according to the DC bus voltage. As shown in FIG. voltage; in the T2 time period, the DC power supply device is in the discharge state, and the DC bus voltage gradually decreases from the floating charging voltage to the cut-off voltage; in the T3 time period, the DC power supply device is in the current-limited charging state, and the DC bus voltage gradually increases from the cut-off voltage. up to the overload voltage; in the time period T4, the DC power supply device is in the voltage-limited charging state, and the DC bus voltage gradually decreases from the cut-off voltage to the floating charging voltage; in the time period T4, the DC power supply device enters the floating charging state again, and the DC bus voltage maintained at the float voltage. Referring to FIG. 3 , the monitoring module can determine the charging state of the DC power supply device according to the change of the DC bus voltage.

103. Adjust the output voltage according to the DC bus voltage and charging state.

Specifically, in order to avoid waste of photovoltaic energy, when the DC bus voltage changes according to the change of charging state, the output voltage of the photovoltaic power supply device is adjusted in real time, so that the input voltage corresponding to the output voltage of the photovoltaic power supply device is greater than the DC bus voltage.

Optionally, the first system parameter further includes the output current of the photovoltaic power supply device and the overload voltage of the battery pack, and the output current of the photovoltaic power supply device is also the output current of the photovoltaic controller. As shown in Figure 4, when the DC power supply device is in the current-limited charging state, step 103 includes:

1031. If the first difference between the overload voltage and the DC bus voltage is greater than or equal to a first preset value, adjust the output voltage so that the output voltage corresponding to the first access voltage is within a preset range.

Wherein, the overload voltage is the maximum charging voltage of the battery pack, and the first access voltage is the voltage at which the photovoltaic power supply device is connected to the DC bus.

Specifically, when the DC power supply device is in the current-limited charging state, the DC power supply device charges the battery pack, and the DC bus voltage gradually rises to the overload voltage. Since the photovoltaic power supply device supplies power to the DC load at the same time when the DC power supply device is in the current-limited charging state, the first access voltage is greater than the DC bus voltage. Therefore, when the DC bus voltage reaches the overload voltage, if the photovoltaic power supply device continues to supply power to the DC load, the first access voltage connected to the DC bus may cause overcharging of the battery pack and damage the battery pack. Therefore, in practice, in the current-limited charging state, the photovoltaic power supply device cannot continue to supply power to the DC load. When the first difference between the overload voltage and the DC bus voltage is less than or equal to the first preset value, the photovoltaic power supply device should be adjusted. Output voltage, so that the photovoltaic power supply device no longer supplies power to the DC load, avoiding the addition of the first access voltage to overcharge the battery pack when the DC bus voltage is close to the overload voltage; and when the first difference between the overload voltage and the DC bus voltage is greater than or When it is equal to the first preset value, the photovoltaic power supply device can supply power to the DC load, and the first access voltage can be greater than the DC bus voltage, less than or equal to any value in the DC bus voltage plus the first preset value, that is, the preset The range is greater than the DC bus voltage and less than or equal to the DC bus voltage plus the first preset value.

Exemplarily, as shown in FIG. 3 , the overload voltage of the 48V battery pack may be 56.4V, the floating charge voltage may be 54V, and the cut-off voltage may be 43.2V. The first preset value can be determined according to the difference between the first access voltage and the DC bus voltage in the floating charge state. For example, in the float charge state, the difference between the first access voltage and the DC bus voltage is 0.3V, then the first The preset value can also be 0.3V. In the embodiment of the present invention, when the first difference between the overload voltage and the DC bus voltage is greater than or equal to 0.3V, the photovoltaic power supply device can continuously supply power to the DC load. At this time, the first access voltage can be greater than the DC bus voltage, It is less than or equal to any value in the DC bus voltage plus the first preset value. If the DC bus voltage is 50V at this time, the first access voltage can be any value in 50V-50.3V.

1032. If the difference between the overload voltage and the DC bus voltage is less than a first preset value, reduce the output voltage to make the output current zero.

Specifically, as shown in FIG. 3 , when the DC power supply device charges the storage battery, the DC bus voltage gradually increases as the storage battery pack is charged. Since the battery pack has an overload voltage, in order to avoid overcharging of the battery pack, the maximum DC bus voltage can be the overload voltage of the battery pack. With the charging of the battery pack, the terminal voltage of the battery pack gradually approaches the DC bus voltage, and the charging of the battery pack is basically completed at this time.

Since the DC bus voltage has reached the overload voltage when the current-limited charging is completed, when the photovoltaic power supply device continues to output power to the DC bus, the output voltage of the photovoltaic power supply device may cause the DC bus voltage to be greater than the overload voltage, thereby overcharging the battery pack , damage the battery pack. Therefore, when the DC bus voltage reaches the overload voltage, the output voltage of the photovoltaic power supply device should be reduced so that the photovoltaic power supply device no longer outputs electric energy to the DC bus, so as to avoid the DC bus voltage being greater than the overload voltage due to the output of the photovoltaic power supply device, resulting in battery failure. Group damage.

Of course, when the photovoltaic power supply device supplies power to the DC load, the access voltage of the photovoltaic power supply device is always greater than the DC bus voltage, and 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 overcharging of the battery pack when the DC bus voltage is close to the overload voltage, the output voltage of the photovoltaic power supply device can be controlled to decrease, so that the photovoltaic power supply device no longer supplies power to the DC load, that is, when the difference between the overload voltage and the DC bus voltage When the value is less than the first preset value, the photovoltaic power supply device no longer supplies power to the DC load.

Exemplarily, the first preset value can be obtained through experiments according to the capacity of the battery pack. For example, for a 48V battery pack, the overload voltage is 56.4V. It can be determined through experiments that the first preset value can be 0.3V, that is, the DC bus voltage is greater than Or equal to 56.1V, when less than or equal to 56.4V, control the output voltage of the photovoltaic power supply device to decrease, and no longer supply power to the DC load.

Optionally, when the DC power supply device is in the voltage-limited charging state, step 103 further includes:

1033. Increase the output voltage with the first step, so that the second access voltage corresponding to the output voltage is greater than the DC bus voltage.

Wherein, the second access voltage is the voltage at which the photovoltaic power supply device is connected to the DC bus.

Specifically, when the current-limited charging of the battery pack is completed, because some batteries in the battery pack may not be fully charged due to uneven charging, the DC power supply device enters the voltage-limited charging state, and the output voltage of the DC power supply device gradually decreases. As the floating charge voltage is lowered, the DC bus voltage and the terminal voltage of the storage battery are also gradually reduced to the float charge voltage. At this time, because the DC bus voltage is already lower than the overload voltage, the output voltage of the photovoltaic power supply device can be controlled to increase and continue to supply power to the DC load.

As shown in Figure 3, in the voltage-limited charging state, because the DC bus voltage is gradually reduced, when the output voltage of the photovoltaic power supply device is controlled to increase to increase the second access voltage, the photovoltaic power supply device can The output voltage of is gradually increased with the first adjustment step, so that the output current is not zero.

1034. If the second difference between the second access voltage and the DC bus voltage is greater than a second preset value, reduce the output voltage with a second step size so that the second difference is smaller than the second preset value.

Specifically, in step 1033, after controlling the output voltage of the photovoltaic power supply device to increase with the first step so that the output current of the photovoltaic power supply device is not zero, if the difference between the second access voltage and the DC bus voltage is greater than For the second preset value, it is also necessary to reduce the output voltage of the photovoltaic power supply device with the first step, so that the second difference is smaller than the second preset value.

Since the output voltage of the photovoltaic power supply device increases according to the first step, the second difference of the second access voltage of the photovoltaic power supply device to the DC bus may be greater than the second preset value, such as the DC bus voltage is 54V, the first The second preset value is 0.3V. When adjusting the output voltage of the photovoltaic power supply device with the first step, the second access voltage may be adjusted from 54V to 54.4V. At this time, the second difference is greater than the second preset value, so it is necessary to The output voltage of the photovoltaic power supply device is reduced with a second step size, so that the second difference is smaller than a second preset value.

It should be noted that the above-mentioned first preset value may be the same as the second preset value, and the first step length is greater than the second step length.

An embodiment of the present invention provides a voltage control method, including: the photovoltaic power supply device obtains the first system parameter; the first system parameter includes the output voltage of the photovoltaic power supply device and the DC bus voltage; the photovoltaic power supply device determines the DC power supply device according to the DC bus voltage Charging state; the charging state includes current-limited charging and voltage-limited charging; the photovoltaic power supply device adjusts the output voltage according to the DC bus voltage and the charging state. The photovoltaic power supply system provided by the embodiments of the present invention can adjust the output voltage of the photovoltaic power supply device in real time according to the DC bus voltage changes in the current-limited charging state and voltage-limited charging state when the DC power supply device is in the equal charge state, ensuring that the photovoltaic power supply device While supplying power to DC loads, avoid overcharging of the battery pack.

As shown in Figure 5, the embodiment of the present invention also provides a photovoltaic power supply device 20, including:

The communication module 201 is configured to obtain a DC bus voltage from a DC power supply device.

The acquiring module 202 is configured to acquire the output voltage of the photovoltaic power supply device 20 .

The processing module 203 is configured to determine the charging state of the DC power supply device according to the DC bus voltage acquired by the communication module 201; the charging state includes current-limited charging and voltage-limited charging.

The adjusting module 204 is configured to adjust the output voltage obtained by the obtaining module 202 according to the DC bus voltage obtained by the communication module 201 and the charging state determined by the processing module 203 .

Optionally, the communication module 201 is also configured to obtain the overload voltage of the battery pack from the DC power supply device.

The obtaining module 202 is also used to obtain the output current of the photovoltaic power supply device 20 .

The adjustment module 204 is specifically used to adjust the output voltage so that the output voltage corresponds to the first preset value if the first difference between the overload voltage and the DC bus voltage is greater than or equal to the first preset value when the DC power supply device is in the current-limited charging state. The access voltage is within a preset range; the overload voltage is the maximum voltage for charging the battery pack, and the first access voltage is the voltage at which the photovoltaic power supply device 20 is connected to the DC bus;

If the difference between the overload voltage and the DC bus voltage is smaller than the first preset value, the output voltage is reduced to make the output current zero.

Optionally, the adjustment module 204 is also specifically configured to increase the output voltage with the first step when the DC power supply device is in the voltage-limited charging state, so that the second access voltage corresponding to the output voltage is greater than the DC bus voltage; the second The access voltage is the voltage at which the photovoltaic power supply device 20 is connected to the DC bus.

Optionally, the adjustment module 204 is also specifically configured to reduce the output voltage with a second step size if the second difference between the second access voltage and the DC bus voltage is greater than a second preset value, so that the second difference less than the second preset value.

An embodiment of the present invention provides a photovoltaic power supply device, including: a communication module, used to obtain the DC bus voltage from the DC power supply device; an acquisition module, used to obtain the output voltage of the photovoltaic power supply device; The DC bus voltage determines the charging state of the DC power supply device; the charging state includes current-limited charging and voltage-limited charging; the adjustment module is used to adjust the output voltage obtained by the acquisition module according to the DC bus voltage obtained by the communication module and the charging state determined by the processing module. The photovoltaic power supply device provided by the embodiment of the present invention can adjust the output voltage of the photovoltaic power supply device in real time according to the DC bus voltage change in the current-limited charging state and the voltage-limited charging state when the DC power supply device is in the equal charge state, ensuring that the photovoltaic power supply device While supplying power to DC loads, avoid overcharging of the battery pack.

Through the description of the above embodiments, those skilled in the art can clearly understand that for the convenience and brevity of the description, only the division of the above-mentioned functional modules is used as an example for illustration. In practical applications, the above-mentioned functions can be allocated according to needs It is completed by different functional modules, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

In the several embodiments provided in this application, it should be understood that the disclosed devices and methods may be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the modules or units is only a logical function division, and there may be other division methods in actual implementation. For example a plurality of units or components may be combined or may be integrated into another device, or some features may be omitted, or not implemented. In another point, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be in electrical, mechanical or other forms. A unit described as a separate component may or may not be physically separated, and a component shown as a unit may be one physical unit or multiple physical units, which may be located in one place or distributed to multiple different places. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units. If an integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the software product is stored in a storage medium Among them, several instructions are included to make a device (which may be a single-chip microcomputer, a chip, etc.) or a processor (processor) execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media capable of storing program codes such as U disk, mobile hard disk, ROM, RAM, magnetic disk or optical disk.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. All should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (6)

1. A voltage control method is applied to a photovoltaic power supply system, the photovoltaic power supply system comprises a direct current bus, and a photovoltaic power supply device and a direct current power supply device which are connected with the direct current bus, and the method is characterized by comprising the following steps:

the photovoltaic power supply device acquires a first system parameter; the first system parameter comprises an output voltage of the photovoltaic power supply device and a direct current bus voltage;

the photovoltaic power supply device determines the charging state of the direct current power supply device according to the direct current bus voltage; the charging state comprises current-limiting charging and voltage-limiting charging;

the photovoltaic power supply device adjusts the output voltage according to the direct current bus voltage and the charging state;

the first system parameters further comprise the output current of the photovoltaic power supply device and the overload voltage of the storage battery pack; when the dc power supply device is in a current-limiting charging state, the adjusting, by the photovoltaic power supply device, the output voltage according to the dc bus voltage and the charging state includes:

if the first difference value between the overload voltage and the direct current bus voltage is larger than or equal to a first preset value, adjusting the output voltage to enable the output voltage to be in a preset range corresponding to a first access voltage; the overload voltage is the maximum voltage charged by the storage battery pack, and the first access voltage is the voltage of the photovoltaic power supply device accessed to the direct-current bus;

and if the difference value between the overload voltage and the direct current bus voltage is smaller than a first preset value, reducing the output voltage to enable the output current to be zero.

2. The voltage control method of claim 1, wherein when the dc power supply is in a voltage limited charging state, the adjusting the output voltage by the photovoltaic power supply according to the dc bus voltage and the charging state further comprises:

increasing the output voltage by a first step length to enable a second access voltage corresponding to the output voltage to be larger than the direct current bus voltage; the second access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus.

3. The voltage control method of claim 2, further comprising, after increasing the output voltage by the first step size:

and if the second difference value between the second access voltage and the direct current bus voltage is greater than a second preset value, reducing the output voltage by a second step length to enable the second difference value to be smaller than the second preset value.

4. A photovoltaic power supply apparatus, comprising:

the communication module is used for acquiring direct-current bus voltage from the direct-current power supply device;

the acquisition module is used for acquiring the output voltage of the photovoltaic power supply device;

the processing module is used for determining the charging state of the direct current power supply device according to the direct current bus voltage acquired by the communication module; the charging state comprises current-limiting charging and voltage-limiting charging;

the adjusting module is used for adjusting the output voltage acquired by the acquiring module according to the direct-current bus voltage acquired by the communication module and the charging state determined by the processing module;

the communication module is also used for acquiring the overload voltage of the storage battery pack from the direct-current power supply device;

the acquisition module is also used for acquiring the output current of the photovoltaic power supply device;

the adjusting module is specifically configured to, when the dc power supply device is in a current-limiting charging state, adjust the output voltage if a first difference between the overload voltage and the dc bus voltage is greater than or equal to a first preset value, so that the output voltage is within a preset range corresponding to a first access voltage; the overload voltage is the maximum voltage charged by the storage battery pack, and the first access voltage is the voltage of the photovoltaic power supply device accessed to the direct-current bus;

and if the difference value between the overload voltage and the direct current bus voltage is smaller than a first preset value, reducing the output voltage to enable the output current to be zero.

5. Photovoltaic power supply device according to claim 4,

the adjusting module is further specifically configured to increase the output voltage by a first step length when the dc power supply device is in a voltage-limiting charging state, so that a second access voltage corresponding to the output voltage is greater than the dc bus voltage; the second access voltage is the voltage of the photovoltaic power supply device accessed to the direct current bus.

6. The photovoltaic power supply device according to claim 5, wherein the adjusting module is further configured to decrease the output voltage by a second step length if a second difference between the second access voltage and the dc bus voltage is greater than a second preset value, so that the second difference is smaller than the second preset value.

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