Photovoltaic power station time synchronization method, data acquisition terminal, inverter and system

Abstract

The invention discloses a photovoltaic power station time synchronization method, a data acquisition terminal, an inverter and a system, and the method comprises the steps: taking the data acquisition terminal as an extension medium, taking a server as a master clock, taking the data acquisition terminal as a slave clock, carrying out the time synchronization with the server based on a preset time protocol, and after the data acquisition terminal and the server complete the time synchronization, carrying out the time synchronization. The data acquisition terminal sends the time synchronization message to the at least one inverter, so that the at least one inverter performs time synchronization with the data acquisition terminal according to the time synchronization message, and high-precision time synchronization between the server and the inverter is realized in a pure software mode on the basis of not increasing hardware cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication technology, in particular to a photovoltaic power station time synchronization method, a data acquisition terminal, an inverter and a system. BACKGROUND

[0002] The high-precision time synchronization technology of the whole station inverter is a core technology in a large photovoltaic power station system, which can ensure that the time references of all devices (such as a background, a data acquisition terminal and an inverter) in the photovoltaic power station are highly consistent, and the precision error is within 1 ms.

[0003] The IEEE 1588 Precision Time Protocol (PTP) can achieve sub-microsecond synchronization of devices in a network, has the characteristics of high precision and high reliability, and mainly benefits from the hardware timestamp, which can capture the hardware timestamp at the physical layer or the network driver layer to reduce the influence of the protocol stack delay and jitter, and significantly improve the precision of time synchronization. However, the acquisition of the physical layer timestamp requires special hardware support. In the photovoltaic power station, if the time synchronization of the server and the inverter is to be realized, a network port and a hardware chip need to be added to the inverter end, which increases the hardware cost. SUMMARY

[0004] Therefore, the present application provides a photovoltaic power station time synchronization method, a data acquisition terminal, an inverter and a system, which realize high-precision time synchronization between a server and an inverter by a pure software method without increasing hardware cost.

[0005] To solve the above problems, the technical scheme provided by the present application is as follows:

[0006] The first aspect of the present application provides a photovoltaic power station time synchronization method applied to a data acquisition terminal, and the photovoltaic power station time synchronization method comprises the following steps:

[0007] Taking a server as a master clock, time synchronization is performed with the server based on a preset time protocol;

[0008] Time synchronization messages are sent to at least one inverter, so that the at least one inverter performs time synchronization with the data acquisition terminal according to the time synchronization messages.

[0009] In a possible implementation, the sending of the time synchronization messages to the at least one inverter comprises the following steps:

[0010] The time synchronization messages sent by an application core of the data acquisition terminal are sent to a real-time core;

[0011] The communication delay between the application core and the real-time core is compensated by using a metronome, and the timer of the real-time core is corrected according to the communication delay;

[0012] At the next whole second of the timer, triggering the real-time core to send a time synchronization message to at least one inverter.

[0013] In a possible implementation, the sending of the time synchronization message to at least one inverter comprises:

[0014] The time synchronization message is sent to the at least one inverter through power carrier communication fast regulation.

[0015] The second aspect of the present application provides a photovoltaic power station time synchronization method applied to an inverter, and the photovoltaic power station time synchronization method comprises:

[0016] In a case where a data acquisition terminal takes a server as a master clock and a preset time protocol is used to complete time synchronization with the server, a time synchronization message sent by the data acquisition terminal is received;

[0017] Time synchronization is performed with the data acquisition terminal according to the time synchronization message.

[0018] In a possible implementation, the receiving of the time synchronization message sent by the data acquisition terminal comprises:

[0019] The time synchronization message sent by the data acquisition terminal is received through power carrier communication fast regulation.

[0020] In a possible implementation, the time synchronization with the data acquisition terminal according to the time synchronization message comprises:

[0021] In a case where the time synchronization message is received for the first time, time synchronization is performed with the data acquisition terminal according to time information in the time synchronization message and a power carrier communication link time delay;

[0022] In a case where the time synchronization message is received again, a clock error with the data acquisition terminal is determined according to time information in the time synchronization message and a power carrier communication link time delay;

[0023] In a case where the clock error is within a preset range, a local clock is adjusted according to the time information in the time synchronization message.

[0024] In a possible implementation, the photovoltaic power station time synchronization method further comprises:

[0025] In a case where the clock error is not within the preset range, the receiving of the time synchronization message sent by the data acquisition terminal is performed;

[0026] If the clock errors determined according to the received time synchronization messages are all not within the preset range within a preset time, a local clock is adjusted according to time information in the latest received time synchronization message.

[0027] The third aspect of the present application provides a data acquisition terminal for performing the photovoltaic power station time synchronization method of the first aspect or any implementation manner of the first aspect.

[0028] The fourth aspect of the present application provides an inverter for performing the photovoltaic power station time synchronization method of the first aspect or any implementation manner of the first aspect.

[0029] The fourth aspect of the present application provides a photovoltaic power station system comprising a server, at least one data acquisition terminal of the third aspect and at least one inverter of the fourth aspect corresponding to the data acquisition terminal.

[0030] The server is in communication connection with the at least one data acquisition terminal.

[0031] The data acquisition terminal is in communication connection with the at least one inverter.

[0032] The photovoltaic power station time synchronization method provided by the embodiments of the present application takes the data acquisition terminal as a transmission medium and takes the server as a master clock and the data acquisition terminal as a slave clock to perform time synchronization with the server based on a preset time protocol. After the data acquisition terminal and the server complete time synchronization, the data acquisition terminal sends a time synchronization message to at least one inverter, so that the at least one inverter performs time synchronization with the data acquisition terminal according to the time synchronization message. In this way, high-precision time synchronization between the server and the inverter is realized by a pure software manner without increasing hardware cost. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The flowchart of the photovoltaic power station time synchronization method provided by the embodiments of the present application is shown.

[0034] Figure 2 The single-cycle interaction diagram of the master clock and the slave clock provided by the embodiments of the present application is shown.

[0035] Figure 3 The multi-cycle interaction diagram of the master clock and the slave clock provided by the embodiments of the present application is shown.

[0036] Figure 4 The flowchart of another photovoltaic power station time synchronization method provided by the embodiments of the present application is shown.

[0037] Figure 5 The structure diagram of the photovoltaic power station system provided by the embodiments of the present application is shown. DETAILED DESCRIPTION

[0038] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation part of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0039] The embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art can know that, with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0040] The terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, and this is only a way of distinguishing the objects with the same attributes in the description of the embodiments of the present application. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, so that the processes, methods, systems, products or equipment containing a series of units do not have to be limited to those units, but can include other units not clearly listed or inherent to these processes, methods, products or equipment.

[0041] There are currently many time synchronization methods, each of which uses a corresponding time synchronization source, such as a network time protocol (NTP) server, B code, GPS, atomic clock, IEEE 1588 precision time protocol (PTP), each of which has its own advantages and disadvantages:

[0042] The network time protocol (NTP) server is simple to deploy and does not require external lines, but is only suitable for environments with network connections and relies on network connections, and network delays and instability can affect the time synchronization accuracy;

[0043] B code time synchronization can only synchronize the inverters under a single subarray at a time, and cannot simultaneously synchronize the inverters under multiple subarrays in the entire station, and increases the cost of the customer's power station on site, and has low implementability;

[0044] GPS satellite signals can provide high-precision time references with an accuracy of microseconds, but require a good satellite signal reception environment, and indoor or signal-shielded environments may not work properly and are susceptible to interference, such as signal shielding or electromagnetic interference, which can affect the time synchronization accuracy;

[0045] Atomic clocks can provide high-precision time synchronization accuracy and excellent stability, but are relatively expensive for power stations and complex to maintain;

[0046] IEEE 1588 precision time protocol (PTP) is suitable for local area network environments, does not require external time sources, has high accuracy, and is suitable for industrial environments that require high-precision synchronization, but requires specialized hardware support to achieve time synchronization accuracy of microseconds, increasing the complexity and cost of the device.

[0047] As can be seen, some of the aforementioned time synchronization methods require the addition of BeiDou time modules, GPS time modules, or hardware chips to improve time synchronization accuracy, thus increasing the hardware cost of time synchronization. Taking the IEEE 1588 Precision Time Protocol (PTP) as an example, to achieve time synchronization between the server and the inverter based on the IEEE 1588 Precision Time Protocol (PTP), a network port and hardware chip need to be added to the inverter, further increasing the hardware cost.

[0048] This embodiment provides a time synchronization method for a photovoltaic power station, applied to a data acquisition terminal in the photovoltaic power station. The data acquisition terminal is a data acquisition, power control, and protocol conversion device used in photovoltaic equipment such as inverters in the photovoltaic power station. The following is a detailed description of the time synchronization method for a photovoltaic power station provided by this application embodiment, with reference to the accompanying drawings.

[0049] Please see Figure 1 , Figure 1 This is a flowchart illustrating a photovoltaic power station time synchronization method provided in an embodiment of this application, as shown below. Figure 1 As shown in the embodiment of this application, a time synchronization method for a photovoltaic power station may include steps 101-102:

[0050] 101: The server serves as the primary clock, and the system synchronizes with the server based on a preset time protocol;

[0051] The system uses the server as the master clock and the data acquisition terminal as the slave clock. It synchronizes with the server based on a preset time protocol. Specifically, the data acquisition terminal interacts with the server based on the preset time protocol, determines the time delay and path delay based on the timestamp of the interaction message, determines the clock error between the terminal and the server based on the time delay and path delay, and synchronizes the time based on the clock error.

[0052] Taking the IEEE 1588 Precision Time Protocol (PTP) as the preset time protocol as an example, the server acts as the PTP master clock, and the data acquisition terminal integrates the PTP framework as the PTP slave clock. The master clock broadcasts an announcement message to the network where the data acquisition terminal is located, announcing its existence and periodically publishing time synchronization messages. The master clock and the slave clock periodically exchange messages.

[0053] like Figure 2 The diagram shown illustrates a single-cycle interaction between the master and slave clocks. One cycle of message interaction includes the following four stages:

[0054] Synchronization (Sync) phase: The master clock sends a Sync message and records the sending timestamp t1; the slave clock records the receiving timestamp t2 when it receives the Sync message.

[0055] Follow_Up stage: the master clock sends a Follow_Up message, the Follow_Up message is embedded with the sending timestamp t1 of the Sync message, and the slave clock parses the Follow_Up message to obtain the timestamp t1 after receiving the message;

[0056] Delay_Req stage: the slave clock sends a Delay_Req message and records the sending timestamp t3, and the master clock records the receiving timestamp t4 when receiving the Delay_Req message;

[0057] Delay_Resp stage: the master clock sends a Delay_Resp message, the Delay_Resp message is embedded with the timestamp t4, and the slave clock parses the Delay_Resp message to obtain the timestamp t4 after receiving the message.

[0058] Let t_offset represent the time delay, and t_delay represent the path delay, then:

[0059] In the Sync stage: t2 = t1 + t_offset + t_delay;

[0060] In the Delay_Resp stage: t4 = t3 - t_offset + t_delay;

[0061] According to the above, t_delay and t_offset can be calculated:

[0062] t_delay = [(t2 - t1) + (t4 - t3)] / 2;

[0063] t_offset = [(t2 - t1) - (t4 - t3)] / 2.

[0064] According to t_offset, the clock error between the master clock and the slave clock is determined, in the case that the clock error is greater than a threshold, the time of the slave clock is directly adjusted, and the phase adjustment of the slave clock is completed; in the case that the clock error is less than or equal to the threshold, the slave clock can keep synchronization with the master clock frequency by fine-tuning the clock frequency of the slave clock.

[0065] For example Figure 3The multi-cycle interaction diagram of the master clock and the slave clock is shown, assuming that the time error of the master clock and the slave clock and the path delay are fixed. If the clock frequencies of the master clock and the slave clock are consistent, the time interval T1n-T1 of the n packets of the Sync message sent by the master clock is the same as the time interval T2n-T2 of the message received by the slave clock. If (T2n-T2) is greater than (T1n-T1), it indicates that the clock frequency of the slave clock is faster than that of the master clock, and the clock frequency of the slave clock needs to be slowed down; otherwise, the clock frequency of the slave clock needs to be accelerated.

[0066] 102: sending a time synchronization message to at least one inverter, so that the at least one inverter synchronizes with the data acquisition terminal according to the time synchronization message.

[0067] The time synchronization message includes time information.

[0068] The data acquisition terminal and the inverter can communicate through various communication links. The time delay of some communication links is relatively fixed, such as a power line carrier (PLC) link. The time delay of some communication links needs to be determined through interactive messages between the data acquisition terminal and the inverter. Therefore, the inverter can synchronize with the data acquisition terminal according to the time information in the time synchronization message and the communication link time delay.

[0069] The embodiment provides a photovoltaic power station time synchronization method. A data acquisition terminal is used as a transmission medium, a server is used as a master clock, and the data acquisition terminal is used as a slave clock to synchronize with the server based on a preset time protocol. After the data acquisition terminal and the server complete time synchronization, the communication connection between the data acquisition terminal and the inverter is multiplexed. The data acquisition terminal sends a time synchronization message to at least one inverter, so that the at least one inverter synchronizes with the data acquisition terminal according to the time synchronization message. The high-precision time synchronization between the server and the inverter is realized through a pure software mode without increasing hardware costs.

[0070] In a possible implementation, the data acquisition terminal includes an application core (also referred to as an A core) and a real-time core (also referred to as an R core). The application core is used to process non-real-time tasks, and the real-time core is used to process real-time response tasks. The actual application scenario is specifically set. After the data acquisition terminal and the server complete time synchronization, the data acquisition terminal sends a time synchronization message issued by the application core to the real-time core, and the real-time core sends the time synchronization message to at least one inverter.

[0071] Since there is a time delay in the inter-core communication between the application core and the real-time core, after the time synchronization message sent by the application core of the data acquisition terminal is sent to the real-time core, the time delay in the communication between the application core and the real-time core needs to be compensated. Specifically, the time delay in the communication between the application core and the real-time core can be compensated by using a metronome. The application core determines the time information in the time synchronization message according to the metronome, and the real-time core acquires the metronome again after receiving the time synchronization message sent by the application core. The difference between the current metronome and the metronome corresponding to the time synchronization message is the time delay in the inter-core communication, which is compensated in the time information of the time synchronization message.

[0072] In addition, the timer of the real-time core also needs to be corrected according to the time delay in the inter-core communication. At the next whole second of the timer, the real-time core triggers the sending of the compensated time synchronization message to at least one inverter.

[0073] In a possible implementation, the data acquisition terminal communicates with the inverter through a power carrier communication link. Since the time delay of the power carrier communication link is relatively stable and can be set according to experimental data, the inverter can synchronize time with the data acquisition terminal according to the time information in the time synchronization message and the time delay of the power carrier communication link, by only sending the time synchronization message to the inverter by the data acquisition terminal.

[0074] In another possible implementation, the data acquisition terminal can also communicate with the inverter through other communication links. If the time delay of the communication link is unstable, the time delay of the communication link needs to be determined through the interactive messages between the data acquisition terminal and the inverter, so as to synchronize time with the data acquisition terminal. The way of determining the time delay of the communication link through the interactive messages between the data acquisition terminal and the inverter is the same as the way of determining the clock error through the interactive messages between the server and the data acquisition terminal in the above embodiment, which will not be described here.

[0075] The embodiment also provides a photovoltaic power station time synchronization method, which is applied to an inverter in a photovoltaic power station. The photovoltaic power station time synchronization method provided by the embodiment of the application will be described in detail below with reference to the accompanying drawings.

[0076] Please refer to Figure 4 , Figure 4 The flowchart of the photovoltaic power station time synchronization method provided by the embodiment of the application is shown in FIG. 4. The photovoltaic power station time synchronization method provided by the embodiment of the application can include steps 401-402. Figure 4

[0077] 401: In the case that the data acquisition terminal synchronizes time with the server based on a preset time protocol with the server as the master clock, receiving the time synchronization message sent by the data acquisition terminal;

[0078] The time synchronization message includes the time information when the data acquisition terminal sends the time synchronization message.​

[0079] 402: Time synchronization is performed according to the time information in the time synchronization message and the data acquisition terminal.

[0080] Specifically, time synchronization is performed according to the time information in the time synchronization message and the communication link delay and the data acquisition terminal.

[0081] In a possible implementation, the inverter receives the time synchronization message sent by the data acquisition terminal through the power carrier communication fast regulation. Since the power carrier communication link delay is relatively stable, the inverter can perform time synchronization with the data acquisition device according to the time information in the time synchronization message and the power carrier communication link delay.

[0082] Specifically, in order to achieve accurate time synchronization, in the case of receiving the time synchronization message for the first time, time synchronization is performed according to the time information in the time synchronization message and the power carrier communication link delay and the data acquisition terminal, to achieve initial time synchronization. In the case of receiving the time synchronization message again subsequently, the clock error with the data acquisition terminal is determined according to the time information in the time synchronization message and the power carrier communication link delay, and time synchronization is performed according to the clock error, where the clock error = local clock - (time information + power carrier communication link delay).

[0083] In a possible implementation, in the case that the clock error is within a preset range (for example, within 1 ms), that is, the clock error is small and within the allowable range, the local clock is adjusted according to the time information in the time synchronization message, to achieve periodic adjustment of the local clock. In the case that the clock error is not within the preset range, since the error is large, in order to avoid the local clock deviation from increasing, the local clock is not adjusted, and the step of receiving the time synchronization message sent by the data acquisition terminal is continued.

[0084] In a short time range, if the clock error determined by the time synchronization message received subsequently is within the preset range, the local clock is adjusted according to the time information in the time synchronization message. If the clock error is not within the preset range within a long time range, for example, within a preset time (for example, 2 min), the clock error is caused by a large local clock deviation, and therefore the local clock is directly adjusted according to the time information in the latest received time synchronization message.

[0085] The photovoltaic power station time synchronization method provided in the embodiment does not depend on a hardware timestamp, does not need to increase a network port and a hardware chip at an inverter end, uses a data acquisition terminal as a transmission medium, uses a server as a master clock, and uses the data acquisition terminal as a slave clock to perform time synchronization with the server. After the data acquisition terminal is successfully time synchronized, the data acquisition terminal further sends a time synchronization message to the inverter through a plc fast adjustment, and the inverter receives the time synchronization message, compensates for a communication link delay, and performs time synchronization. Since it is not necessary to increase hardware costs and increase a network port at the inverter end, on the basis of reducing hardware costs, the server to the inverter full-link 1 ms high-precision time synchronization is realized in a pure software manner.

[0086] The embodiment of the application further provides a data acquisition terminal used for executing the photovoltaic power station time synchronization method.

[0087] Taking a server as a master clock, time synchronization is performed with the server based on a preset time protocol;

[0088] A time synchronization message is sent to at least one inverter, so that the at least one inverter performs time synchronization with the data acquisition terminal according to the time synchronization message.

[0089] Further, the time synchronization message sent to the at least one inverter comprises:

[0090] The time synchronization message sent by an application core of the data acquisition terminal is sent to a real-time core;

[0091] A metronome is used to compensate for a communication delay between the application core and the real-time core, and a timer of the real-time core is corrected according to the communication delay;

[0092] At a next whole second of the timer, the real-time core is triggered to send a time synchronization message to at least one inverter.

[0093] Further, the time synchronization message sent to the at least one inverter comprises:

[0094] The time synchronization message is sent to the at least one inverter through power carrier communication fast adjustment.

[0095] The embodiment of the application further provides an inverter used for executing the photovoltaic power station time synchronization method.

[0096] In a case where a data acquisition terminal performs time synchronization with a server based on a preset time protocol, taking the server as a master clock, a time synchronization message sent by the data acquisition terminal is received;

[0097] Time synchronization is performed with the data acquisition terminal according to the time synchronization message.

[0098] Further, the time synchronization message sent by the data acquisition terminal comprises:

[0099] synchronize with the data acquisition terminal according to the time information in the time synchronization message and the power line communication link time delay.

[0100] Further, the time synchronization with the data acquisition terminal according to the time synchronization message comprises:

[0101] In a case of first receiving the time synchronization message, time synchronization with the data acquisition terminal is performed according to the time information in the time synchronization message and the power line communication link time delay.

[0102] In a case of receiving the time synchronization message again, a clock error with the data acquisition terminal is determined according to the time information in the time synchronization message and the power line communication link time delay.

[0103] In a case that the clock error is within a preset range, a local clock is adjusted according to the time information in the time synchronization message.

[0104] Further, the photovoltaic power station time synchronization method further comprises:

[0105] In a case that the clock error is not within the preset range, the step of receiving the time synchronization message sent by the data acquisition terminal is performed.

[0106] If the clock errors determined according to the received time synchronization messages are all not within the preset range within a preset time, a local clock is adjusted according to the time information in the latest received time synchronization message.

[0107] The embodiment of the present application also provides a photovoltaic power station system, which comprises a server, at least one data acquisition terminal provided by the embodiment of the present application and at least one inverter corresponding to the data acquisition terminal and provided by the embodiment of the present application.

[0108] The server is in communication connection with the at least one data acquisition terminal.

[0109] The data acquisition terminal is in communication connection with the at least one inverter.

[0110] Please refer to Figure 5 The photovoltaic power station system shown in the figure, the server as the master clock, the data acquisition terminal as the slave clock.

[0111] For example, the server can be selected as a PTP time server, a message interaction period (i.e. the period of the time synchronization message sent by the server) is set, and the server is connected to a local area network. The server publishes an announce message to the local area network, announces its existence and periodically publishes a time synchronization message, and periodically interacts with the data acquisition terminal.

[0112] Selecting a PTP clock source on the visual Web interface of the data acquisition terminal, setting the data acquisition terminal as a PTP slave clock, and selecting a network port for interaction between the server and the data acquisition terminal, the network port is connected to the local area network through the interaction machine.

[0113] The data acquisition terminal records a file when the time synchronization with the server is successful, and deletes the file when the time synchronization fails, the file is used to represent whether the PTP time synchronization between the server and the data acquisition terminal is completed. In addition, whether the PTP time synchronization failure occurs can also be checked on the visual Web interface of the data acquisition terminal, if the PTP time synchronization failure occurs, it indicates that the PTP master-slave clock time synchronization fails, if the PTP time synchronization failure does not occur, it indicates that the PTP master-slave clock time synchronization succeeds.

[0114] The data acquisition terminal includes an application core and a real-time core. The application core includes a PTP slave clock module, a port module, and a data processing module (Dp), the user interacts with the port module through the visual Web interface, selects a PTP clock source, sets the data acquisition terminal as a PTP slave clock, makes the PTP slave clock module realize time synchronization with the server, and the user can also interact with the port module through the visual Web interface to issue a data processing task to the data processing module. The real-time core includes a Dsp1 core, and the Dsp1 core communicates with at least one inverter through a PLC communication link.

[0115] In the case that the PTP master-slave clock time synchronization succeeds, the data acquisition terminal periodically issues a time synchronization message from the application core to the real-time core, wherein the time information in the time synchronization message is determined according to the metronome, the real-time core acquires the metronome again after receiving the time synchronization message, the difference between the current metronome and the metronome corresponding to the time synchronization message is the inter-core communication delay, the real-time core compensates the inter-core communication delay to the time information in the time synchronization message, and corrects the timer of the real-time core according to the inter-core communication delay, at the next whole second of the timer, the real-time core sends the compensated time synchronization message to at least one inverter.

[0116] The data acquisition terminal corresponds to at least one inverter, and the real-time core of the data acquisition terminal communicates with the inverter through a power carrier communication link, specifically, issues a time synchronization message to the inverter through the power carrier communication fast adjustment. When the real-time core of the data acquisition terminal issues the time synchronization message to the inverter through the power carrier communication fast adjustment, the polling of the power carrier communication fast adjustment port is performed, since the power carrier communication usually adopts a specific frequency band, the specific frequency band that is suitable for adaptation can be automatically selected through the frequency band judgment, and the frequency band incompatibility is avoided. In addition, in order to prevent the time synchronization message from being lost, the time synchronization message can be issued multiple times (such as 3 times) in each time synchronization period.

[0117] The inverter can be an inverter including a DSP or an inverter including an ARM and a DSP. The inverter receives the time synchronization message. In the case of receiving the time synchronization message for the first time, the inverter synchronizes the time with the data acquisition terminal according to the time information in the time synchronization message and the power line communication link delay. Specifically, the time information in the received time synchronization message is compensated by using the power line communication link delay as the time of the local clock. In the case of receiving the time synchronization message for the second time, the inverter determines the clock error with the data acquisition terminal according to the time information in the time synchronization message and the power line communication link delay. Specifically, the clock error = local clock - (time information + power line communication link delay). In the case that the clock error is within a preset range (for example, within 1 ms), the local clock is adjusted according to the time information in the time synchronization message. In the case that the clock error is not within the preset range, the local clock is not adjusted due to the large error, and the step of receiving the time synchronization message sent by the data acquisition terminal is continued. Within a preset time, if the clock error determined according to the received time synchronization message is within the preset range, the local clock is adjusted according to the time information in the time synchronization message; if the clock error determined according to the received time synchronization message is not within the preset range, the local clock is directly adjusted according to the time information in the latest received time synchronization message.

[0118] In the above embodiments, the implementation can be achieved by software, hardware, firmware or any combination thereof, in whole or in part. When implemented by software, the implementation can be achieved in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the whole or part of the process or function according to the embodiments of the present application is generated. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media. The available media can be magnetic media (such as floppy disk, hard disk, magnetic tape), or semiconductor media (such as solid state disk (SSD)) and the like.

[0119] The embodiments of the present application also provide a readable storage medium for storing the method provided by the above embodiments. For example, random access memory (RAM), flash memory, read only memory (ROM), EPROM memory, non-volatile read only memory (Electronic Programmable ROM, EPROM), register, hard disk, removable disk or any other form of storage medium in the art.

[0120] It should be noted that the various embodiments described in the specification are progressive, and each embodiment focuses on the differences from other embodiments. The same or similar parts of each embodiment can be referred to each other. For the method disclosed in the embodiments, since it corresponds to the product embodiments disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the product embodiments.

[0121] The above description of disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications of the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of time synchronizing a photovoltaic power plant, the method comprising: The photovoltaic power station time synchronization method applied to a data acquisition terminal comprises: Taking a server as a master clock, and synchronizing time with the server based on a preset time protocol; Sending a time synchronization message to at least one inverter, so that the at least one inverter synchronizes time with the data acquisition terminal according to the time synchronization message.

2. The photovoltaic power plant time keeping method according to claim 1, characterized in that, The step of sending the time synchronization message to at least one inverter comprises: Sending the time synchronization message sent by an application core of the data acquisition terminal to a real-time core; Compensating a communication delay between the application core and the real-time core by using a metronome, and correcting a timer of the real-time core according to the communication delay; Triggering the real-time core to send a time synchronization message to at least one inverter at a next whole second of the timer.

3. A method of time synchronizing a photovoltaic power plant according to claim 1 or 2, characterized in that, The step of sending the time synchronization message to at least one inverter comprises: Sending the time synchronization message to the at least one inverter through power carrier communication fast adjustment.

4. A method of time synchronizing a photovoltaic power plant, characterized by, The photovoltaic power station time synchronization method applied to an inverter comprises: In a case that a data acquisition terminal synchronizes time with a server based on a preset time protocol, receiving a time synchronization message sent by the data acquisition terminal; Synchronizing time with the data acquisition terminal according to the time synchronization message.

5. The method of time keeping for a photovoltaic power plant of claim 4, wherein, The step of receiving the time synchronization message sent by the data acquisition terminal comprises: Receiving the time synchronization message sent by the data acquisition terminal through power carrier communication fast adjustment.

6. The photovoltaic power plant time keeping method according to claim 5, characterized in that, The step of synchronizing time with the data acquisition terminal according to the time synchronization message comprises: In a case that the time synchronization message is received for the first time, synchronizing time with the data acquisition terminal according to time information in the time synchronization message and a power carrier communication link delay; In a case that the time synchronization message is received again, determining a clock error with the data acquisition terminal according to time information in the time synchronization message and a power carrier communication link delay; In a case that the clock error is within a preset range, adjusting a local clock according to the time information in the time synchronization message.

7. The method of time keeping for a photovoltaic power plant of claim 6, wherein, The photovoltaic power station time synchronization method further comprises: In a case that the clock error is not within the preset range, performing the step of receiving the time synchronization message sent by the data acquisition terminal; In a case that the clock error determined according to the received time synchronization message is not within the preset range within a preset time, adjusting the local clock according to time information in the latest received time synchronization message.

8. A data collection terminal, characterized by A photovoltaic power station time synchronization method for performing any one of claims 1-3.

9. An inverter, characterized by comprising: A photovoltaic power station time synchronization method for performing any one of claims 4-7.

10. A photovoltaic power plant system, characterized by, Comprise: a server, at least one data acquisition terminal of claim 8, and at least one inverter of claim 9 corresponding to the data acquisition terminal; The server is in communication connection with at least one data acquisition terminal; The data acquisition terminal is in communication connection with at least one inverter.

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