CN118174572A

CN118174572A - Control method and device of photovoltaic system, photovoltaic system and electronic equipment

Info

Publication number: CN118174572A
Application number: CN202410599376.2A
Authority: CN
Inventors: 包鑫康; 肖云鹏
Original assignee: Hefei Sigeyuan Intelligent Technology Co ltd
Current assignee: Hefei Sigeyuan Intelligent Technology Co ltd
Priority date: 2024-05-15
Filing date: 2024-05-15
Publication date: 2024-06-11

Abstract

The application discloses a control method and device of a photovoltaic system, the photovoltaic system and electronic equipment, and belongs to the technical field of photovoltaics. The method includes obtaining a current duty cycle of each of the boost converters in the inverter; determining a control signal phase shift angle for each of the boost converters in the inverter based on the current duty cycles of the at least two boost converters; and controlling the boost converter to be conducted according to the phase shift angle of the control signal of the boost converter so as to minimize current ripple input into the direct current arc fault detection unit. The method can enable the current ripple of the input direct current arc fault detection unit to be minimum, is suitable for the condition that the input photovoltaic power is different, ensures the normal operation of the direct current arc fault detection unit, reduces the missed judgment and the erroneous judgment of the direct current arc fault detection unit, ensures the safe and reliable operation of the photovoltaic system, and reduces the system cost.

Description

Control method and device of photovoltaic system, photovoltaic system and electronic equipment

Technical Field

The application belongs to the technical field of photovoltaics, and particularly relates to a control method and device of a photovoltaic system, the photovoltaic system and electronic equipment.

Background

The string inverter realizes the high-efficiency utilization of each path of photovoltaic string through multi-path power tracking, has the remarkable advantage of being free from the influence of the performance difference and the local shadow shielding of the photovoltaic cell assemblies among strings, and is widely applied to various photovoltaic systems. The string inverter is generally formed by cascading two stages of conversion circuits, wherein the former stage is a multi-path direct current Boost conversion circuit (Boost DC-DC), and the latter stage is a direct current alternating current inverter circuit (DC-AC).

The inverter is typically configured with a direct-current Arc-detection (AFCI) unit that, by identifying an Arc Fault signature in the Circuit, opens the power Circuit before the Arc Fault develops into a fire or the Circuit is shorted. The AFCI unit judges through sampling analysis of the cable current, and when arc faults occur on the direct current side, the cable current generates a characteristic arc fault frequency spectrum which is different from that in normal operation in a frequency band of 10kHz-100 kHz.

However, when multiple Boost parallel operation is performed, the common AFCI unit may superimpose current ripple of the input Boost inductor, resulting in a substantial increase in the magnitude of the current ripple of the input AFCI unit. Because the switching frequency of the inverter system is usually in the frequency range of 10kHz-100kHz, the frequency range belongs to the characteristic frequency range of direct current arc faults, and the increase of the ripple amplitude of the input Boost inductor current can obviously interfere the normal operation of the AFCI device, so that the direct current arc faults are missed and misjudged, and the safe and reliable operation of the photovoltaic system is seriously endangered.

Disclosure of Invention

The present application aims to solve at least one of the technical problems existing in the prior art. Therefore, the application provides a control method and device of a photovoltaic system, the photovoltaic system and electronic equipment, which can minimize current ripple input into an AFCI, ensure normal operation of the AFCI and improve safety and reliability of the photovoltaic system.

In a first aspect, the present application provides a control method of a photovoltaic system, the photovoltaic system including at least two photovoltaic modules, an inverter and a dc arc fault detection unit, the inverter including at least two boost converters connected in parallel, the method comprising:

acquiring a current duty cycle of each boost converter in the inverter;

Determining a control signal phase shift angle for each of the boost converters in the inverter based on the current duty cycles of the at least two boost converters;

According to the control signal phase shifting angle of the boost converter, the boost converter is controlled to be conducted so as to enable current ripple input into the direct current arc fault detection unit to be minimum, the direct current arc fault detection unit comprises at least two sampling ends which are in one-to-one correspondence with the at least two boost converters, the sampling ends are arranged at the input ends of the inductors of the boost converters, and the direct current arc fault detection unit is used for detecting the direct current arc fault of the photovoltaic module based on current signals sampled by the sampling ends.

According to the control method of the photovoltaic system, the current duty ratio of the boost converter is used for representing the difference condition of photovoltaic input power, the control signal phase shift angle of each boost converter is calculated according to the current duty ratio, the boost converter is controlled to be conducted by the control signal phase shift angle, the current ripple of the input direct current arc fault detection unit is enabled to be minimum, the control method is suitable for the condition that the input photovoltaic power is different, normal operation of the direct current arc fault detection unit is guaranteed, leakage judgment and misjudgment of the direct current arc fault detection unit are reduced, safe and reliable operation of the photovoltaic system is guaranteed, and system cost is reduced.

According to one embodiment of the application, said determining a control signal phase shift angle for each of said boost converters in said inverter based on said current duty cycles of said at least two boost converters comprises:

Constructing a current ripple relation of an inductor input into the boost converter by taking a duty ratio as a parameter;

Based on the current ripple relation of the at least two boost converters, constructing an interference ripple relation of the inverter by taking a duty ratio and a phase shift angle as parameters;

and solving the interference ripple relation based on the current duty ratios of the at least two boost converters to obtain the control signal phase shifting angle of each boost converter.

According to an embodiment of the present application, the constructing an interference ripple relation of the inverter based on the current ripple relation of the at least two boost converters with a duty cycle and a phase shift angle as parameters includes:

Determining a peak-to-valley value of a current ripple of an inductance input to the at least two boost converters based on the current ripple relation of the boost converters;

The disturbance ripple relation is constructed based on the peak-to-valley value of the current ripple of the inductance input to the at least two boost converters.

According to one embodiment of the application, said solving the interference ripple relation based on the current duty cycles of the at least two boost converters comprises:

The interference ripple relation is solved based on the current duty cycle of the at least two boost converters, with the minimum peak-to-valley value of the current ripple of the inductance input to the at least two boost converters being the target.

According to one embodiment of the application, the interference ripple relation is as follows:

；

Wherein, Representing current ripple input to the DC arc fault detection unit,/>Phase shift angle representing turn-on of kth boost converter relative to 1 st boost converter, k= … n,/>Current ripple representing the inductance of the input j-th boost converter, j= … n,/>Representing the current time,/>Representing a switching period of the inverter;

peak value representing current ripple of inductance input to the at least two boost converters,/> A valley representing a current ripple of an inductance input to the at least two boost converters.

According to one embodiment of the application, the current ripple relation is as follows:

；

Wherein, Representing the current ripple of the j-th boost converter input to the inductor, j= … n,/>Representing the duty cycle corresponding to the jth boost converter,/>Indicating the current time.

and based on the current duty ratios of the at least two boost converters, performing table lookup operation on a phase shift angle mapping table of the inverter, and determining the control signal phase shift angle of each boost converter, wherein the phase shift angle mapping table is used for storing the mapping relation between the duty ratio and the phase shift angle.

According to one embodiment of the present application, the phase shift angle map is obtained by:

acquiring a duty cycle set of the at least two boost converters and an interference ripple relation of the inverter;

And traversing the duty cycle set, and solving the interference ripple relation to obtain the phase-shifting angle mapping table.

According to one embodiment of the application, the obtaining the current duty cycle of each of the boost converters in the inverter includes:

Acquiring current input voltages of the at least two boost converters and direct current bus voltages of the inverter;

The current duty cycle of the boost converter is determined based on the dc bus voltage and the current input voltage of the boost converter.

In a second aspect, the present application provides a control device for a photovoltaic system, the photovoltaic system including at least two photovoltaic modules, an inverter and a dc arc fault detection unit, the inverter including at least two boost converters connected in parallel, the device comprising:

an acquisition module for acquiring a current duty cycle of each of the boost converters in the inverter;

A processing module for determining a control signal phase shift angle for each of the boost converters in the inverter based on the current duty cycles of the at least two boost converters;

The control module is used for controlling the boost converter to be conducted according to the phase shifting angle of the control signal of the boost converter so as to enable current ripple input into the direct current arc fault detection unit to be minimum, the direct current arc fault detection unit comprises at least two sampling ends which are in one-to-one correspondence with the at least two boost converters, the sampling ends are arranged at the input ends of the inductors of the boost converters, and the direct current arc fault detection unit is used for detecting the direct current arc fault of the photovoltaic module based on current signals sampled by the sampling ends.

In a third aspect, the present application provides a photovoltaic system comprising:

At least two photovoltaic modules;

an inverter comprising at least two boost converters connected in parallel;

the direct current arc fault detection unit comprises at least two sampling ends which are in one-to-one correspondence with the at least two boost converters, the sampling ends are arranged at the input ends of the inductors of the boost converters, and the direct current arc fault detection unit is used for detecting the direct current arc fault of the photovoltaic module based on current signals sampled by the sampling ends;

And the controller is connected with the inverter and the direct current arc fault detection unit and is used for executing the control method of the photovoltaic system in the first aspect.

According to the photovoltaic system disclosed by the application, the controller characterizes the difference condition of the photovoltaic input power through the current duty ratio of the boost converter, calculates the control signal phase shifting angle of each boost converter according to the current duty ratio, controls the boost converter to be conducted, can enable the current ripple of the input direct current arc fault detection unit to be minimum, is suitable for the condition that the input photovoltaic power is different, ensures the normal operation of the direct current arc fault detection unit, reduces the omission judgment and the misjudgment of the direct current arc fault detection unit, ensures the safe and reliable operation of the photovoltaic system, and reduces the system cost.

According to one embodiment of the application, the controller is further configured to control all switching devices of the inverter to be turned off when the dc arc fault detection unit detects that the dc arc fault occurs in the photovoltaic module.

According to one embodiment of the application, the inverter comprises ten of the boost converters connected in parallel;

each boost converter is connected with one photovoltaic module, or each boost converter is connected with at least two photovoltaic modules in parallel.

According to one embodiment of the application, the direct current arc fault detection unit comprises a current transformer, the current transformer comprises at least two primary windings and one secondary winding, the at least two primary windings and the secondary winding are coupled, the sampling ends are connected with the primary windings in a one-to-one correspondence manner, and the direct current arc fault detection unit is used for detecting direct current arc faults based on current signals of the secondary windings.

In a fourth aspect, the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the control method of the photovoltaic system according to the first aspect when executing the computer program.

In a fifth aspect, the present application provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a method of controlling a photovoltaic system as described in the first aspect above.

In a sixth aspect, the present application provides a computer program product comprising a computer program which, when executed by a processor, implements a method of controlling a photovoltaic system as described in the first aspect above.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Drawings

The foregoing and/or additional aspects and advantages of the application will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic flow chart of a control method of a photovoltaic system according to an embodiment of the present application;

FIG. 2 is a schematic circuit diagram of a photovoltaic system according to an embodiment of the present application;

fig. 3 is a schematic diagram of output of control signals of two boost converters in a photovoltaic system according to an embodiment of the present application;

FIG. 4 is a schematic diagram of current ripple cancellation of two boost converters in a photovoltaic system provided by an embodiment of the present application;

FIG. 5 is a second flow chart of a control method of a photovoltaic system according to an embodiment of the present application;

FIG. 6 is a schematic diagram of current ripple input to an AFCI without phase shifting angle for two boost converters in the related art;

FIG. 7 is a schematic diagram of the current ripple of the input AFCI with two boost converters of the related art at a fixed pi phase shift angle;

FIG. 8 is a schematic diagram of current ripple input into an AFCI at a phase shift angle of two boost converters in a photovoltaic system provided by an embodiment of the present application;

FIG. 9 is a schematic diagram of a difference in phase angle between two boost converter interval control signals compared to an input AFCI current ripple without phase angle in a photovoltaic system provided by an embodiment of the present application;

FIG. 10 is a schematic diagram of the difference in ripple of input AFCI current in a photovoltaic system with two boost converters spaced apart by a control signal phase shift angle compared to a fixed pi phase shift angle provided by an embodiment of the present application;

FIG. 11 is a second schematic circuit diagram of a photovoltaic system according to an embodiment of the present application;

Fig. 12 is a schematic diagram showing the output of control signals of n boost converters in a photovoltaic system according to an embodiment of the present application;

FIG. 13 is a second flow chart of a control method of a photovoltaic system according to an embodiment of the present application;

fig. 14 is a schematic structural diagram of a control device of a photovoltaic system according to an embodiment of the present application;

fig. 15 is a schematic hardware diagram of an electronic device according to an embodiment of the present application.

Reference numerals:

The system comprises a direct current arc fault detection unit 200, a signal processing unit 210, a controller 300, a direct current bus 400 and a power grid 500.

Detailed Description

The technical solutions of the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which are obtained by a person skilled in the art based on the embodiments of the present application, fall within the scope of protection of the present application.

The terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged, as appropriate, such that embodiments of the present application may be implemented in sequences other than those illustrated or described herein, and that the objects identified by "first," "second," etc. are generally of a type, and are not limited to the number of objects, such as the first object may be one or more. Furthermore, in the description and claims, "and/or" means at least one of the connected objects, and the character "/", generally means that the associated object is an "or" relationship.

The method for controlling the photovoltaic system, the device for controlling the photovoltaic system, the electronic device and the readable storage medium provided by the embodiment of the application are described in detail below by specific embodiments and application scenes thereof with reference to the accompanying drawings.

The photovoltaic system comprises at least two photovoltaic modules, an inverter and a direct current arc fault detection unit 200.

The photovoltaic module is used for converting the light energy into electric energy, the photovoltaic module is connected with the inverter, and the inverter converts the photovoltaic direct-current electric energy into alternating-current electric energy and outputs the alternating-current electric energy.

The direct current Arc Fault detection unit 200 (AFCI) in the photovoltaic system detects the direct current Arc Fault of the photovoltaic system by identifying the Arc Fault characteristic signals in the connection Circuit of the photovoltaic module and the inverter, and breaks the Circuit before the Arc Fault develops into a fire or the Circuit is short-circuited, so as to ensure the safe operation of the photovoltaic system.

In this embodiment, the inverter comprises at least two boost converters connected in parallel.

The boost converter can convert the low-voltage electric energy input by the photovoltaic module into high-voltage electric energy.

In this embodiment, each boost converter may be connected to one photovoltaic module, and each boost converter may also be connected to two or more photovoltaic modules in parallel.

In actual implementation, the inverter further includes a DC bus 400 and an inverter circuit (DC-AC), at least two boost converters are connected in parallel to the DC bus 400, the DC bus 400 is connected to the inverter circuit, and the inverter circuit converts the high-voltage DC power output by the boost converters into AC power.

In this embodiment, the dc arc fault detection unit 200 includes at least two sampling terminals corresponding to at least two boost converters one by one, the sampling terminals are disposed at the input terminals of the inductors of the boost converters, and the dc arc fault detection unit 200 is configured to perform dc arc fault detection on the photovoltaic module based on the current signals sampled by the sampling terminals.

Each sampling end of the direct current arc fault detection unit 200 correspondingly collects current signals on a connecting loop of one boost converter, namely, a plurality of photovoltaic modules of a photovoltaic system and a plurality of boost converters of an inverter share one direct current arc fault detection unit 200 for detection, and the direct current arc fault detection cost of the system is lower.

It will be appreciated that when multiple boost converters in an inverter are operated in parallel, the common dc arc fault detection unit 200 will superimpose current ripple input to the inductances of the different boost converters.

The photovoltaic system comprises two photovoltaic modules, and the inverter comprises two boost converters which are connected in parallel.

As shown in fig. 2, the photovoltaic modules PV ₁ and PV ₂ are respectively connected to a boost converter, and the dc arc fault detection unit 200 has two sampling terminals, one sampling terminal is connected between the photovoltaic modules PV ₁ and the inductor L ₁ of the boost converter, and the other sampling terminal is connected between the photovoltaic modules PV ₂ and the inductor L ₂ of the boost converter.

In this embodiment, during inverter operation, the common dc arc fault detection unit 200 will superimpose current ripple input to the inductor L ₁ and the inductor L ₂. In some embodiments, the dc arc fault detection unit 200 includes a current transformer, where the current transformer includes at least two primary windings and one secondary winding, the at least two primary windings and the secondary winding are coupled, and the sampling end is connected to the primary windings in a one-to-one correspondence, and the dc arc fault detection unit 200 is configured to perform dc arc fault detection based on a current signal of the secondary winding.

The current signals collected by the sampling ends are coupled with the primary winding and the secondary winding, and the plurality of boost converters share one current transformer to superpose current ripples of inductances input to different boost converters.

The embodiment of the application provides a control method of a photovoltaic system, which considers the situation that the input power of different boost converters is different, takes the duty ratio of a plurality of boost converters as a control object, realizes the minimum ripple control of the current of the input direct current arc fault detection unit 200 of the boost converters, ensures the accuracy of the direct current arc fault detection unit 200 for detecting the direct current arc fault, improves the safety and the reliability of the system, and reduces the cost of the system.

The execution main body of the control method of the photovoltaic system provided by the embodiment of the application can be an electronic device or a functional module or a functional entity capable of realizing the control method of the photovoltaic system in the electronic device, and the control method of the photovoltaic system provided by the embodiment of the application is described below by taking the electronic device as the execution main body.

As shown in fig. 1, the control method of the photovoltaic system includes: step 110, step 120 and step 130.

Step 110, obtaining a current duty cycle of each boost converter in the inverter.

In this step, for each boost converter in the inverter, the current duty ratio corresponding to the boost converter at the current time is acquired.

For example, as shown in fig. 2, the photovoltaic module PV ₁ and the photovoltaic module PV ₂ are respectively connected to a boost converter, the current duty cycle corresponding to the connection of the photovoltaic module PV ₁ to the boost converter is D ₁, and the corresponding switching devices Q ₁₁ are closed and Q ₁₂ are opened for a duration percentage of one switching cycle; the current duty cycle of the photovoltaic module PV ₂ connected to the boost converter is D ₂, and the corresponding switching devices Q ₂₁ are closed and Q ₂₂ are open for a percentage of the duration of one switching cycle.

It can be appreciated that due to the different aging degree, illumination intensity, conversion efficiency and other factors between the photovoltaic modules, there may be a difference between the input powers of the photovoltaic modules, i.e. there may be a difference between the powers of the boost converters connected in parallel.

In this embodiment, the voltage of the input boost converter of the photovoltaic module PV ₁ is U _pv1, the voltage of the input boost converter of the photovoltaic module PV ₂ is U _pv2, and the two boost converters are connected in parallel to the dc bus 400.

It is understood that two or more boost converters are connected in parallel to a common dc bus, and the output power of the dc bus is determined according to the input powers of the two or more boost converters, and the difference condition of the input powers of the boost converters can be represented by the duty ratios corresponding to the boost converters.

In actual implementation, for an inverter comprising two boost converters, when the boost converter is operating in continuous mode, there isAnd/>The relation of (2) may be a voltage of a DC bus/>And the duty cycle of the boost converter to characterize the difference in input power of the boost converter.

Step 120, determining a control signal phase shift angle for each boost converter in the inverter based on the current duty cycles of the at least two boost converters.

In this step, according to the condition of the input power of the boost converter reflected by the current duty cycle of the boost converter, the control signal phase shift angle of each boost converter in the inverter is calculated, and the phase of the current input inductance of the boost converter is adjusted by the control signal phase shift angle, so that the current ripple of the direct current arc fault detection unit 200 shared by different boost converter inputs can cancel each other.

The phase shift angle of the control signal refers to the phase difference which is staggered when the boost converters connected in parallel in the inverter output currents, namely the phase difference which is staggered when signals for controlling the switching devices of the boost converters are switched.

It should be noted that the control signal phase shift angle is a relative value, and the control signal phase shift angle of each boost converter in the inverter is different.

When the inverter includes two boost converters, the phase shift angle of the control signal of one boost converter is 0, and the phase shift angle of the control signal of the other boost converter is α, which means that the signals between the two boost converters that control the switching devices need to be shifted from each other by α.

When the inverter includes three boost converters, the phase shift angle of the control signal of one boost converter is 0, the phase shift angles of the control signals of the other two boost converters are α1 and α2, and signals for controlling the switching devices between the other two boost converters and the boost converter which is 0 need to be staggered by α1 and α2 respectively.

Step 130, the boost converter is controlled to be turned on according to the phase shift angle of the control signal of the boost converter, so as to minimize the current ripple input to the dc arc fault detection unit 200.

In this step, according to the phase shift angle of the control signal of each boost converter, the switching device of the boost converter may be controlled to trigger and conduct, so as to adjust the signal input phases of the boost converters in the inverter, and the current ripple of the input inductor in the different boost converters may cancel each other when entering the common dc arc fault detection unit 200, so that the current ripple of the input dc arc fault detection unit 200 is minimum, and the normal operation of the dc arc fault detection unit 200 is ensured.

As shown in fig. 2, the photovoltaic modules PV ₁ and PV ₂ are respectively connected to a boost converter, and the dc arc fault detection unit 200 has two sampling terminals, one sampling terminal is disposed at the input terminal of the inductor L ₁ of the boost converter, and the other sampling terminal is disposed at the input terminal of the inductor L ₂ of the boost converter.

In this embodiment, the current duty cycle of the photovoltaic module PV ₁ connected to the boost converter is D ₁, the current duty cycle of the photovoltaic module PV ₂ connected to the boost converter is D ₂, and the control signal phase shifting angles of the two boost converters are calculated according to D ₁ and D ₂.

The phase shift angle of the control signal corresponding to the photovoltaic module PV ₁ connected to the boost converter is 0, and the phase shift angle of the control signal corresponding to the photovoltaic module PV ₂ connected to the boost converter is alpha.

As shown in fig. 3, the phase difference of the triggering conduction of the switching devices controlling the boost converter is α, i.e. the carrier phase shift α of the switching devices of the boost converter is turned on.

As shown in fig. 4, f _s is the switching frequency of the boost converter, calculated according to the switching period T _s, f _s=1/T_s, the current ripple i _L1 of the inductor L ₁ and the current ripple i _L2 of the inductor L ₂ in the inverter cancel each other, so that the current ripple i ₀ of the input dc arc fault detection unit 200 is minimum, and the current ripple amplitude of the input dc arc fault detection unit 200 is reduced and superimposed.

According to the control method of the photovoltaic system, provided by the embodiment of the application, the current duty ratio of the boost converters is used for representing the difference condition of photovoltaic input power, the control signal phase shift angle of each boost converter is calculated according to the current duty ratio, the boost converters are controlled to be conducted by the control signal phase shift angle, the current ripple input into the direct current arc fault detection unit 200 can be enabled to be minimum, the control method is suitable for the condition that the input photovoltaic power is different, the normal operation of the direct current arc fault detection unit 200 is ensured, the omission judgment and the misjudgment of the direct current arc fault detection unit 200 are reduced, the safe and reliable operation of the photovoltaic system is ensured, and the system cost is reduced.

In some embodiments, determining a control signal phase shift angle for each of the boost converters in the inverter based on the current duty cycles of the at least two boost converters may include:

constructing a current ripple relation of the inductance of the input boost converter by taking the duty ratio as a parameter;

based on the current ripple relation of at least two boost converters, constructing an interference ripple relation of an inverter by taking a duty ratio and a phase shift angle as parameters;

and solving an interference ripple relation based on the current duty ratios of at least two boost converters to obtain a control signal phase shift angle of each boost converter.

In this embodiment, a current ripple relation of the inductance input to each boost converter is constructed with the duty cycle of each boost converter in the inverter as a parameter, which characterizes the current ripple condition of the input inductance when the boost converter is operated at a certain duty cycle.

For example, as shown in fig. 2, the duty cycle of the photovoltaic module PV ₁ connected to the boost converter is denoted as D ₁, and the duty cycle of the photovoltaic module PV ₂ connected to the boost converter is denoted as D ₂.

The voltage of the input boost converter of the photovoltaic module PV ₁ is U _pv1, the voltage of the input boost converter of the photovoltaic module PV ₂ is U _pv2, and the parallel multi-channel boost converter is connected to the direct current bus 400.

When the boost converter Q ₁₁ connected to the photovoltaic module PV ₁ is closed, Q ₁₂ is open, the inductor current of inductor L ₁ rises with a fixed slope K ₁,。

When the Q ₁₁ of the photovoltaic module PV ₁ connected to the boost converter is off, Q ₁₂ is on, the inductor current drops with a fixed slope K ₂,。

The current ripple i _L1 of the inductance of the boost converter to which the photovoltaic module PV ₁ is connected can be expressed as a piecewise function over time as follows:

；

wherein T _s is a switching period, and T represents the current time.

Similarly, the current ripple i _L2 of the inductance of the boost converter to which the photovoltaic module PV ₂ is connected can be expressed as a piecewise function over time as follows:

；

wherein T _s is a switching period, and T represents the current time.

When the boost converter is operating in continuous mode, there isAnd/>The piecewise function form of the current ripple of the inductance of the two boost converters can be transformed as follows:

；

Wherein U _bus is the voltage of the dc bus 400, and T _s is the switching period.

In actual implementation, a current ripple relation of the inductor of the input boost converter may be constructed according to a duty cycle related to the input power of the boost converter, where the inductor L ₁, the inductor L ₂, the switching period T _s, and the voltage U _bus of the dc bus 400 are generally constant with specific values, and the inductance in the same inverter is generally equal,。

Order theThe current ripple relation of the inductances of the two boost converters can be obtained as follows:

；

Wherein, Current ripple characteristics characterizing the inductance of a boost converter to which a photovoltaic module PV ₁ is connected,/>The current ripple characteristics characterizing the inductance of the boost converter to which the photovoltaic module PV ₂ is connected.

In this embodiment, the current ripple characteristic input across the inductance of the boost converter may be characterized by a parameter of the duty cycle of the boost converter, i.e., the current ripple relation is parameterized by the duty cycle as an unknown quantity.

In some embodiments, the current ripple relation is as follows:

；

Wherein, Current ripple representing input inductance of jth boost converter, j= … n,/>Representing the duty cycle corresponding to the jth boost converter,/>Indicating the current time.

For example, for an inverter comprising n boost converters, the current ripple relation comprises:

；

…

。

It will be appreciated that the current ripple input to the dc arc fault detection unit 200 is the result of the mutual influence of the current ripple of the inductances of the plurality of boost converters, and the phase shift angle is introduced as an unknown based on the current ripple relation, and an interference ripple relation of the inverter is constructed, and the current duty cycle of each boost converter in the inverter is brought into the inverter, and the control signal phase shift angle of each boost converter is obtained by the interference ripple relation.

In some embodiments, constructing the interference ripple relation of the inverter with the duty cycle and the phase shift angle as parameters based on the current ripple relation of the at least two boost converters may include:

determining a peak-to-valley value of current ripple of an inductor input to the at least two boost converters based on a current ripple relation of the boost converters;

An interference ripple relation is constructed based on the peak-to-valley values of the current ripple of the inductances input to the at least two boost converters.

Wherein, the peak-valley value refers to the difference between the peak value and the valley value in a certain time range.

In this embodiment, the current ripple of the input dc arc fault detection unit 200 is a current ripple of the inductors of the plurality of boost converters, and according to the current ripple relation of each boost converter, a phase shift angle parameter is introduced, which characterizes the peak value and the valley value of the current ripple of the superimposed current ripple of the input inductors of all the boost converters of the inverter under the control of the phase shift angle, and according to the difference between the peak value and the valley value, an interference ripple relation of the current ripple of the input dc arc fault detection unit 200 is constructed.

In some embodiments, the interference ripple relation is as follows:

；

Taking an example in which the inverter comprises two boost converters.

The current ripple relation of the inductances of the two boost converters is as follows:

；

Order the ，/>The interference ripple relation of the current ripple input to the dc arc fault detection unit 200 is as follows:

；/>

；

Wherein, Y represents current ripple of the input direct current arc fault detection unit 200, and alpha is a phase shift angle to be solved;

peak value of current ripple of the input inductance for both boost converters, The dip of the current ripple of the inductor is input for both boost converters.

In some embodiments, solving the interference ripple relation based on the current duty cycles of the at least two boost converters includes:

The interference ripple relation is solved based on the current duty cycle of the at least two boost converters, with the goal of minimizing the peak-to-valley value of the current ripple of the inductor input to the at least two boost converters.

In this embodiment, the current ripple of the inductors of the different boost converters is cancelled by the phase difference, and the peak-to-valley value of the current ripple of all the inductors of the input inverter is targeted to be minimum, and under the condition of determining the current duty cycle, the optimal phase shift angle of each boost converter, that is, the control signal phase shift angle, is solved.

In actual execution, in a switching period, the on-off of a switching device of the boost converter is controlled through a control signal phase-shifting angle, so that the current ripple input into the direct current arc fault detection unit 200 is minimum, the normal operation of the direct current arc fault detection unit 200 can be ensured, the missed judgment and the misjudgment of the direct current arc fault detection unit 200 are reduced, and the safe and reliable operation of a photovoltaic system is ensured.

TABLE 1

In some embodiments, determining a control signal phase shift angle for each of the boost converters in the inverter based on the current duty cycles of the at least two boost converters comprises:

And based on the current duty ratio of at least two boost converters, performing table lookup operation on a phase shift angle mapping table of the inverter, and determining a control signal phase shift angle of each boost converter.

The phase shift angle mapping table is used for storing the mapping relation between the duty ratio and the phase shift angle.

In this embodiment, the phase-shift angle mapping table may be obtained by experimental verification parameters or the like, or may be obtained by solving the above-mentioned interference ripple relation.

In actual implementation, according to the current duty ratios of all the boost converters in the inverter, table lookup operation is performed in the phase shift angle mapping table, so as to obtain the control signal phase shift angle corresponding to each boost converter.

For example, the inverter includes two boost converters, and corresponding control signal phase shift angles are found in the phase shift angle maps shown in tables 1 and 2 according to the current duty cycles of the two boost converters.

The control signal phase shift angle is a relative value, the control signal phase shift angle of one boost converter is 0, and the control signal phase shift angle found in the phase shift angle mapping table is the phase shift angle of the other boost converter relative to the control signal phase shift angle of the boost converter, that is, the phase difference of signals of the switching devices of the two boost converters, which are staggered with each other.

TABLE 2

In this embodiment, table 1 shows the control signal phase shift angle values for one of the boost converters having a duty cycle D ₁ in the range of 0.05-0.95 and the other boost converter having a duty cycle D ₂ in the range of 0.05-0.50; table 2 shows control signal phase shift angle values for one of the boost converters having a duty cycle D ₁ in the range of 0.05-0.95 and the other boost converter having a duty cycle D ₂ in the range of 0.55-0.95.

It should be noted that when the inverter includes more than two boost converters, the phase-shifting angle mapping table of the inverter is multidimensional, and the phase-shifting angle mapping table may include two or more sub-tables, where each sub-table is used to represent the value of the phase-shifting angle of the control signal corresponding to the duty ratio of two adjacent boost converters in parallel connection.

In some embodiments, the phase shift angle map is obtained by:

acquiring a duty cycle set of at least two boost converters and an interference ripple relation of an inverter;

traversing the duty cycle set, and solving the interference ripple relation to obtain the phase shift angle mapping table.

The duty cycle set comprises a plurality of feasible duty cycle values of each boost converter, the duty cycle set is traversed, interference ripple relation of the inverter is solved, the optimal control signal phase shift angle corresponding to each duty cycle is obtained, the phase shift angle mapping table is obtained, direct lookup in the follow-up practical application process is facilitated, the phase shift angle mapping table is determined, and control efficiency is improved.

For example, the inverter includes two boost converters, and the interference ripple relation of the current ripple input to the dc arc fault detection unit 200 is as follows:

；

traversing the duty cycle set, solving the interference ripple relation, obtaining a phase-shift angle mapping table, directly looking up a table to determine the phase-shift angle mapping table, controlling the switching device of the boost converter to trigger conduction according to the phase-shift angle of the control signal obtained by looking up the table, so that the current ripple input into the direct current arc fault detection unit 200 is minimum, the safe and reliable operation of the photovoltaic system is ensured, and the system cost is reduced.

In some embodiments, obtaining the current duty cycle of each boost converter in the inverter includes:

acquiring current input voltages of at least two boost converters and DC bus voltages of an inverter;

In this embodiment, the current duty cycle of the boost converter may be calculated by taking the current input voltage of the boost converter (i.e., the output voltage of the connected photovoltaic module) and the dc bus voltage of the inverter.

For example, as shown in fig. 2, the photovoltaic module PV ₁ and the photovoltaic module PV ₂ are each connected to one boost converter, the voltage input to the boost converter by the photovoltaic module PV ₁ is U _pv1, the voltage input to the boost converter by the photovoltaic module PV ₂ is U _pv2, and the two boost converters are connected in parallel to the dc bus 400.

When the boost converter is operating in continuous mode, there isAnd/>The current duty cycle for the photovoltaic module PV ₁ to connect to the boost converter is D ₁ and the current duty cycle for the photovoltaic module PV ₂ to connect to the boost converter is D ₂.

The control method of the photovoltaic system is applied to the photovoltaic system, and the current duty ratio is calculated by collecting the output voltage of the photovoltaic module and the DC bus voltage of the inverter, and the corresponding control signal phase shift angle is solved, so that the minimum current ripple input into the DC arc fault detection unit 200 is realized, the detection performance of the DC arc fault detection unit 200 of the system is improved, the safety and reliability of the system are improved, and the system cost is reduced.

A specific embodiment is described below.

As shown in fig. 5, for an inverter comprising two boost converters, the solution is traversed such that the optimum phase shift angle α is such thatTaking the minimum value.

The set of the optimal control signal phase shift angles α (D ₁,D₂) for both boost converters, i.e. the phase shift angle map, is obtained.

Collecting output voltages U _pv1 and U _pv2 of two paths of photovoltaic modules, namely, inputting the voltages of two boost converters, collecting the voltages at a direct-current bus voltage U _bus, and calculating the current duty ratios D ₁ and D of the two boost converters _2.

According to the current duty ratios D ₁ and D ₂, the control signal phase shift angle alpha (D ₁,D₂) of the optimal ripple control is obtained through table lookup, and the phase shift angles of the two boost converters are set to be alpha, so that the minimum ripple control of the input AFCI is realized.

Fig. 6 is a schematic diagram of current ripple of the input AFCI when two boost converters have no phase shift angle, and as shown in fig. 6, the maximum value of the current ripple of the input AFCI when no phase shift angle reaches 0.500 at each duty cycle D ₁、D₂.

Fig. 7 is a schematic diagram of current ripple of the input AFCI when pi-shifted angles of the two boost converters are fixed in the related art, and as shown in fig. 7, the maximum value of the current ripple of the input AFCI when pi-shifted angles are fixed is 0.385 in each duty cycle D ₁、D₂. Fig. 8 is a schematic diagram of current ripple of an input AFCI when two boost converters in the photovoltaic system provided by the embodiment of the application interval control signals phase shift, and as shown in fig. 8, the maximum value of the input AFCI current ripple when interval optimal control signals phase shift is only 0.285 under the condition of each duty ratio D ₁、D₂.

In this embodiment, the xy axis of the graph corresponds to the input duty cycle of the respective boost converter, and the z axis represents the current ripple (normalized value) of the input AFCI, which can be represented by U _bus/L.

Fig. 9 is a schematic diagram showing the difference between the phase shift angles of two boost converter interval control signals in the photovoltaic system provided by the embodiment of the application compared with the input AFCI current ripple without the phase shift angle, as shown in fig. 9, under the condition of each duty ratio D ₁、D₂, the phase shift angle α can effectively reduce the input AFCI current ripple relative to the non-phase shift angle, and as can be seen from the figure, under the optimal phase shift angle control, the phase shift angle α scheme can reduce the current ripple by 86.0% compared with the non-phase shift angle scheme.

Fig. 10 is a schematic diagram showing the difference between the phase shift angles of two boost converter interval control signals in the photovoltaic system provided by the embodiment of the application compared with the fixed pi phase shift angle input AFCI current ripple, as shown in fig. 10, under the condition of each duty ratio D ₁、D₂, the phase shift angle α can effectively reduce the input AFCI current ripple relative to the fixed pi phase shift angle, and as can be seen from the figure, under the control of the optimal phase shift angle, the phase shift angle α scheme can reduce the current ripple by 66.6% compared with the fixed pi phase shift angle scheme.

In the embodiment, the current duty ratio of the boost converter is obtained, the phase shift angle of the control signal is calculated, the minimum ripple control of the input AFCI current is realized under the condition that the input power of different boost converters is different through the scheme of changing the phase shift angle, the detection performance of the AFCI is improved, the safety and the reliability of the system are improved, and the cost of the system is reduced.

According to the control method of the photovoltaic system provided by the embodiment of the application, the execution main body can be a control device of the photovoltaic system. In the embodiment of the application, a control device of a photovoltaic system is taken as an example to execute a control method of the photovoltaic system, and the control device of the photovoltaic system provided by the embodiment of the application is described.

The embodiment of the application also provides a control device of the photovoltaic system, the photovoltaic system comprises at least two photovoltaic modules, an inverter and a direct current arc fault detection unit 200, and the inverter comprises at least two boost converters connected in parallel.

As shown in fig. 14, the control device of the photovoltaic system includes:

An acquisition module 1410 for acquiring a current duty cycle of each boost converter in the inverter;

A processing module 1420 to determine a control signal phase shift angle for each of the boost converters in the inverter based on the current duty cycles of the at least two boost converters;

The control module 1430 is configured to control the boost converter to be turned on according to a phase shift angle of a control signal of the boost converter, so as to minimize current ripple of an inductor of the input dc arc fault detection unit 200, where the dc arc fault detection unit 200 includes at least two sampling ends corresponding to the at least two boost converters one by one, the sampling ends are disposed at an input end of the inductor of the boost converter, and the dc arc fault detection unit 200 is configured to perform dc arc fault detection on the photovoltaic module based on a current signal sampled by the sampling ends.

According to the control device of the photovoltaic system, provided by the embodiment of the application, the current duty ratio of the boost converters is used for representing the difference condition of photovoltaic input power, the control signal phase shift angle of each boost converter is calculated according to the current duty ratio, the boost converters are controlled to be conducted by the control signal phase shift angle, the current ripple input into the direct current arc fault detection unit 200 can be enabled to be minimum, the control device is suitable for the condition that the input photovoltaic power is different, the normal operation of the direct current arc fault detection unit 200 is ensured, the omission judgment and the misjudgment of the direct current arc fault detection unit 200 are reduced, the safe and reliable operation of the photovoltaic system is ensured, and the system cost is reduced.

In some embodiments, processing module 1420 is configured to construct a current ripple relation of the inductance of the input boost converter with the duty cycle as a parameter;

In some embodiments, processing module 1420 is configured to determine a peak-to-valley value of a current ripple of an inductance of at least two boost converters based on a current ripple relation of the boost converters;

In some embodiments, the processing module 1420 is configured to solve the interference ripple relation based on the current duty cycles of the at least two boost converters with the goal of minimizing the peak-to-valley value of the current ripple input to the inductances of the at least two boost converters.

In some embodiments, the interference ripple relation is as follows:

；

Wherein, Representing current ripple of input DC arc fault detection unit,/>Phase shift angle representing turn-on of kth boost converter relative to 1 st boost converter, k= … n,/>Current ripple representing inductance input to jth boost converter, j= … n,/>Representing the current time,/>Representing a switching period of the inverter;

peak value representing current ripple of inductance input to at least two boost converters,/> A valley of a current ripple representing an inductance of the input at least two boost converters.

In some embodiments, the current ripple relation is as follows:

；

In some embodiments, the processing module 1420 is configured to perform a table look-up operation on a phase shift angle mapping table of the inverter based on the current duty cycles of at least two boost converters, to determine a control signal phase shift angle of each boost converter, where the phase shift angle mapping table is used to store a mapping relationship between the duty cycle and the phase shift angle.

In some embodiments, the phase shift angle map is obtained by:

In some embodiments, an acquisition module 1410 for acquiring the current input voltage of at least two boost converters and the dc bus voltage of the inverter;

The control device of the photovoltaic system in the embodiment of the application can be electronic equipment or a component in the electronic equipment, such as an integrated circuit or a chip.

The control device of the photovoltaic system provided by the embodiment of the present application can implement each process implemented by the embodiment of the method of fig. 1, and in order to avoid repetition, a detailed description is omitted here.

The embodiment of the application also provides a photovoltaic system.

The photovoltaic system includes at least two photovoltaic modules, an inverter, a direct current arc fault detection unit 200, and a controller 300.

In actual implementation, each boost converter may be connected to one photovoltaic module, or each boost converter may be connected to two or more photovoltaic modules in parallel.

The direct current arc fault detection unit 200 comprises at least two sampling ends corresponding to the at least two photovoltaic modules one by one, the sampling ends are arranged at the input ends of the inductors of the boost converter, and the direct current arc fault detection unit 200 is used for detecting the direct current arc fault of the photovoltaic modules based on current signals sampled by the sampling ends.

The controller 300 is connected to the inverter and the dc arc fault detection unit 200, and the controller 300 is used to perform the control method of the photovoltaic system described above.

In actual implementation, the controller 300 may be connected with a sampling device in the photovoltaic system, obtain parameters such as the current duty ratio of the boost converter of the inverter, the current input voltage, and the dc bus voltage of the inverter, calculate, and write a phase shift angle mapping table into the controller 300, and look up a table to obtain the phase shift angle of the control signal.

According to the photovoltaic system provided by the embodiment of the application, the controller 300 characterizes the difference condition of the photovoltaic input power through the current duty ratio of the boost converter, calculates the control signal phase shift angle of each boost converter according to the current duty ratio, and controls the boost converter to be conducted, so that the current ripple of the input direct current arc fault detection unit 200 is minimum, the photovoltaic system is suitable for the condition that the input photovoltaic power is different, the normal operation of the direct current arc fault detection unit 200 is ensured, the leakage judgment and the misjudgment of the direct current arc fault detection unit 200 are reduced, the safe and reliable operation of the photovoltaic system is ensured, and the system cost is reduced.

In some embodiments, the controller 300 is further configured to control all switching devices of the inverter to be turned off in a case where the dc arc fault detection unit 200 detects that the photovoltaic module has a dc arc fault.

In this embodiment, the dc arc fault detection unit 200 includes a signal processing unit 210, where the signal processing unit 210 processes the received current signal to determine whether a dc arc fault occurs, and when determining that the dc arc fault occurs, the controller 300 outputs information to the controller 300, and the controller 300 controls all switching devices of the inverter to be turned off, so as to ensure the safety of the photovoltaic system.

For example, as shown in fig. 2, the photovoltaic system includes a photovoltaic module PV ₁ and a photovoltaic module PV ₂, and when it is determined that a dc arc fault occurs, Q ₁₁ and Q ₁₂ of the boost converter connected to the photovoltaic module PV ₁ are disconnected, and Q ₂₁ and Q ₂₂ of the boost converter connected to the photovoltaic module PV ₂ are disconnected.

The photovoltaic system acquires the current duty ratio of the boost converter, calculates the phase shift angle of the control signal, realizes minimum ripple control of the input AFCI current under the condition that the input power of different boost converters is different through the scheme of changing the phase shift angle, improves the detection performance of the AFCI, increases the safety and the reliability of the system, and reduces the cost of the system.

In some embodiments, the inverter includes ten boost converters in parallel; each boost converter is connected with one photovoltaic module, or each boost converter is connected with at least two photovoltaic modules in parallel.

The 10 boost converters corresponding to the inverters are connected in parallel to the direct current bus 400, the direct current arc fault detection unit 200 is provided with 10 sampling ends in total, the sampling ends are arranged at the input ends of the inductors of the boost converters, the 10 boost converters share one direct current arc fault detection unit 200, and the direct current arc fault detection unit 200 superimposes current ripples input to the inductors of different boost converters.

In this embodiment, the controller 300 may obtain parameters such as the current duty cycle of each boost converter of the inverter, the current input voltage, and the dc bus voltage of the inverter, and calculate by using the interference ripple relation, to obtain a phase shift angle of the control signal corresponding to each boost converter.

The interference ripple relation may be as follows:

；/>

In this embodiment, the phase shift angle of the control signal of the 1 st boost converter is 0, Phase shift angle indicating turn-on of the 2 nd boost converter relative to the 1 st boost converter,/>Indicating the phase shift angle of the turn-on of the 3 rd boost converter relative to the 1 st boost converter, and so on.

By calculating the phase shift angle of the control signal, under the condition that the input power of different boost converters is different, the minimum ripple control of the input AFCI current is realized, the influence of the current ripple superposition of the inductance of the different boost converters on the detection performance of the AFCI is prevented, the safety and the reliability of the system are improved, and the cost of the system is reduced.

In some embodiments, the dc arc fault detection unit 200 includes a current transformer, where the current transformer includes at least two primary windings and one secondary winding, the at least two primary windings and the secondary winding are coupled, and the sampling end is connected to the primary windings in a one-to-one correspondence, and the dc arc fault detection unit 200 is configured to perform dc arc fault detection based on a current signal of the secondary winding.

As shown in fig. 2, the current transformer includes 2 primary windings, which are respectively connected to the inductor L ₁ and the inductor L ₂, current signals collected by the two primary windings are i _L1 and i _L2, current signals output by the corresponding secondary windings are i _o, and the signal processing unit 210 of the dc arc fault detection unit 200 performs dc arc fault detection according to the current signal i _o.

As shown in fig. 11, the current transformer includes n primary windings, which are respectively connected to the inductor L ₁ and the inductor L ₂ … inductor L _n, the current signals collected by the n primary windings are i _L1、i_L2…i_Ln, the current signal output by the corresponding secondary winding is i _o, and the signal processing unit 210 of the dc arc fault detection unit 200 performs dc arc fault detection according to the current signal i _o.

It can be understood that the current signals collected by the plurality of sampling ends are coupled with the primary winding and the secondary winding, the plurality of boost converters share one current transformer, the current transformers superimpose current ripples input to inductances of different boost converters, the controller carries out conduction control of the boost converters by calculating a phase shift angle of a control signal, the minimum ripple control of input current can be realized, the influence of the current ripple superposition on the detection performance of the direct current arc fault detection unit 200 is prevented, the safety and the reliability of the system are improved, and the common current transformer can also reduce the system cost.

The controller calculates the phase shift angle of the control signal to conduct control of the boost converter, and is also applicable to other situations where current ripple superposition of the boost converter occurs.

The photovoltaic system of the embodiment of the application controls the conduction of the boost converter by calculating the phase shift angle of the control signal, can effectively prevent the superposition of current ripple from influencing the detection performance of the direct current arc fault detection unit 200, and improves the safety and reliability of the system.

A specific embodiment is described below.

As shown in fig. 11, the photovoltaic system includes n photovoltaic modules PV ₁、PV₂…PV_n, n boost converters corresponding to the inverters are connected in parallel to a DC bus 400, a capacitor C _bus is disposed on the DC bus 400, the DC bus 400 is connected to an inverter circuit DC-AC, and the converted AC power is integrated into a power grid 500.

As shown in fig. 13, the solution is traversed using a program such that the following equation takes a minimum value:

；

Wherein,

；

；/>

…

；

In this embodiment, the traversal solution yields a phase shift angle map of the optimal control signal phase shift angle α₁(D₁,D₂,...D_n),α₂(D₁,D₂,...D_n),...α_n-1(D₁,D₂,...D_n) for the plurality of boost converters at each duty cycle D ₁,D₂,...D_n.

And collecting output voltage U _pv1,U_pv2,...U_pvn of the multi-path photovoltaic module, collecting direct-current bus voltage U _bus, and calculating to obtain the current duty ratios D ₁,D₂,...D_n of the plurality of boost converters.

According to the current duty ratio D ₁,D₂,...D_n, looking up a table to obtain an optimal control signal phase shift angle α₁(D₁,D₂,...D_n),α₂(D₁,D₂,...D_n),...α_n-1(D₁,D₂,...D_n).

In this embodiment, the phase shift angles of the plurality of boost converters are set to be α ₁,α₂,...α_n-1, as shown in fig. 12, the phase shift angle of the 2 nd boost converter relative to the 1 st boost converter is set to be α ₁, the phase shift angle of the 3rd boost converter relative to the 1 st boost converter is set to be α ₃, and so on, finally, the minimum ripple control of the input AFCI current of the plurality of boost converters is realized, the condition of difference in input power is applicable, the minimum current ripple control can be realized for the photovoltaic system under each working condition, the detection performance of the AFCI is improved, and the safe and reliable operation of the system is ensured.

In some embodiments, as shown in fig. 15, an electronic device 1500 is further provided in the embodiments of the present application, which includes a processor 1501, a memory 1502 and a computer program stored in the memory 1502 and capable of running on the processor 1501, where the program when executed by the processor 1501 realizes the respective processes of the above-mentioned embodiments of the control method of the photovoltaic system, and the same technical effects are achieved, and for avoiding repetition, a detailed description is omitted herein.

The electronic device in the embodiment of the application includes the mobile electronic device and the non-mobile electronic device.

The embodiment of the application also provides a non-transitory computer readable storage medium, on which a computer program is stored, which when executed by a processor, implements the processes of the control method embodiment of the photovoltaic system, and can achieve the same technical effects, and in order to avoid repetition, the description is omitted here.

Wherein the processor is a processor in the electronic device described in the above embodiment. The readable storage medium includes computer readable storage medium such as computer readable memory ROM, random access memory RAM, magnetic or optical disk, etc.

The embodiment of the application also provides a computer program product, which comprises a computer program, and the computer program realizes the control method of the photovoltaic system when being executed by a processor.

The embodiment of the application further provides a chip, the chip comprises a processor and a communication interface, the communication interface is coupled with the processor, the processor is used for running programs or instructions, the processes of the control method embodiment of the photovoltaic system can be realized, the same technical effects can be achieved, and the repetition is avoided, and the description is omitted here.

It should be understood that the chips referred to in the embodiments of the present application may also be referred to as system-on-chip chips, chip systems, or system-on-chip chips, etc.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of the present application is not limited to performing the functions in the order shown or discussed, but may also include performing the functions in a substantially simultaneous manner or in an opposite order depending on the functions involved, e.g., the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art in the form of a computer software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) comprising instructions for causing a terminal (which may be a mobile phone, a computer, a server, or a network device, etc.) to perform the method according to the embodiments of the present application.

The embodiments of the present application have been described above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present application and the scope of the claims, which are to be protected by the present application.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A control method of a photovoltaic system, characterized in that the photovoltaic system comprises at least two photovoltaic modules, an inverter and a direct current arc fault detection unit, the inverter comprising at least two boost converters connected in parallel, the method comprising:

acquiring a current duty cycle of each boost converter in the inverter;

2. The method of claim 1, wherein the determining a control signal phase shift angle for each of the boost converters in the inverter based on the current duty cycles of the at least two boost converters comprises:

3. The method according to claim 2, wherein the constructing the disturbance ripple relation of the inverter based on the current ripple relation of the at least two boost converters with a duty cycle and a phase shift angle as parameters includes:

4. A control method of a photovoltaic system according to claim 3, wherein said solving the interference ripple relation based on the current duty cycles of the at least two boost converters comprises:

5. A method of controlling a photovoltaic system according to claim 3, wherein the disturbance ripple relation is as follows:

；

6. The method of claim 2, wherein the current ripple relation is as follows:

；

7. The method of any of claims 1-6, wherein the determining a control signal phase shift angle for each of the boost converters in the inverter based on the current duty cycles of the at least two boost converters comprises:

8. The method of claim 7, wherein the phase-shift angle map is obtained by:

9. The method of any one of claims 1-6, wherein the obtaining a current duty cycle of each of the boost converters in the inverter comprises:

10. A control device of a photovoltaic system, characterized in that the photovoltaic system comprises at least two photovoltaic modules, an inverter and a direct current arc fault detection unit, the inverter comprises at least two boost converters connected in parallel, the device comprises

11. A photovoltaic system, comprising:

At least two photovoltaic modules;

an inverter comprising at least two boost converters connected in parallel;

a controller connected to the inverter and the dc arc fault detection unit, the controller being configured to perform the control method of the photovoltaic system according to any one of claims 1 to 9.

12. The photovoltaic system of claim 11, wherein the controller is further configured to control all switching devices of the inverter to open if the dc arc fault detection unit detects that the photovoltaic module is experiencing a dc arc fault.

13. The photovoltaic system of claim 11, wherein the inverter comprises ten of the boost converters in parallel;

14. The photovoltaic system of any of claims 11-13, wherein the dc arc fault detection unit comprises a current transformer comprising at least two primary windings and one secondary winding, the at least two primary windings and the secondary winding being coupled, the sampling terminals being connected in one-to-one correspondence with the primary windings, the dc arc fault detection unit being configured to perform dc arc fault detection based on a current signal of the secondary winding.

15. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the control method of the photovoltaic system according to any of claims 1-9 when executing the program.

16. A non-transitory computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed by a processor, implements a method of controlling a photovoltaic system according to any one of claims 1-9.