Clock synchronization method of energy storage system, energy storage converter and energy storage system

Abstract

The embodiment of the present application relates to the technical field of energy storage systems, and provides a clock synchronization method of an energy storage system, an energy storage converter and an energy storage system, the method comprising: obtaining a cable length between a first controller and a second controller closest to the first controller, obtaining a first cable distance, and determining a first delay time according to at least the first cable distance, the first delay time being a phase difference value between a clock of the second controller closest to the first controller and a clock of the first controller; and sending the first delay time to the second controller within a preset time period, so that the second controller adds the clock of the second controller and the first delay time, thereby realizing clock synchronization between the first controller and the second controller closest to the first controller. The clock synchronization method of the energy storage system can at least solve the problem that the clock synchronization of the first controller and the second controller in the prior art energy storage system needs optical fiber electrical connection, resulting in high cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage systems, and particularly relates to a clock synchronization method of an energy storage system, an energy storage converter and an energy storage system. BACKGROUND

[0002] A power conversion system (PCS), also known as an energy storage inverter, is one of the core devices in an energy storage system. The PCS includes power conversion components (such as IGBTs), control components, protection components, communication modules, and heat dissipation systems (such as including heat sinks, fans, or liquid cooling plates), and other components.

[0003] In the PCS, the master and slave architectures are usually used to implement distributed control, functional division, and system expansion functions. The functions of the master include system control and management, data processing and analysis, and user interface and interaction. The functions of the slave include local control and execution and cooperative operation. The master and slave perform their respective functions in the PCS system. The master is responsible for centralized control, data management, and user interaction. The slave is responsible for specific power conversion and local control. Through the cooperative work of the master and the slave, the PCS system can achieve efficient, flexible, and reliable operation.

[0004] In the prior art energy storage system, optical fibers are often used to electrically connect the first controller and the second controller, resulting in high cost. SUMMARY

[0005] Embodiments of the present application provide a clock synchronization method of an energy storage system, an energy storage converter and an energy storage system, which at least solve the problem of high cost caused by the need for optical fiber electrical connection for clock synchronization of the first controller and the second controller in the prior art energy storage system.

[0006] According to some embodiments of the present application, the present application provides a clock synchronization method of an energy storage system, which is applied to a first controller in the energy storage system. The first controller is electrically connected to one of all second controllers in the energy storage system by a cable. The second controller electrically connected to the first controller is in series connection with other second controllers by the cable. The first controller and the second controllers have the same structure. The first controller comprises a digital signal processor and a field programmable gate array. The digital signal processor and the field programmable gate array are in bidirectional communication. The field programmable gate array of the first controller is electrically connected to the field programmable gate array of the first controller by the cable. The first controller is used to centrally control the second controllers. The second controllers are used to adjust the power of the energy storage system. The method comprises the following steps: obtaining the cable length between the first controller and the second controller closest to the first controller to obtain a first cable distance, and determining a first delay time according to at least the first cable distance. The first delay time is the phase difference value between the clock of the second controller closest to the first controller and the clock of the first controller. The first delay time is sent to the second controllers within a preset time period, so that the second controllers add the clock of the second controllers and the first delay time to realize the clock synchronization between the first controller and the second controller closest to the first controller.

[0007] In some embodiments, after the first delay time is sent to the second controllers within a preset time period, the method further comprises the following steps: in the case that there is at least one faulty device in all the second controllers, and the faulty device is the second controller closest to the first controller, issuing a shutdown instruction to the second controllers other than the second controller electrically connected to the first controller to control the second controllers other than the second controller electrically connected to the first controller to shut down; in the case that there is at least one faulty device in all the second controllers, and the faulty device is not the second controller closest to the first controller, issuing the shutdown instruction to a target controller to control the target controller to shut down. The target controller is the second controller other than the faulty device and all the second controllers between the faulty device and the first controller.

[0008] In some embodiments, after sending the first delay time to the second controller within the preset time period, the method further comprises: obtaining a current cable distance between the first controller and the second controller closest to the first controller after a preset time period; determining that the second controller does not need to be synchronized again in a case that an absolute value of a difference between the current cable distance and the first cable distance is less than or equal to a preset difference; and determining a difference between a clock of the second controller closest to the first controller and a clock of the first controller according to at least the current cable distance to obtain a current delay time, and sending the current delay time to the second controller within the preset time period to make the second controller add the clock of the second controller and the current delay time.

[0009] In some embodiments, before sending the first delay time to the second controller within the preset time period, the method further comprises: obtaining a first time mapping relationship, the first time mapping relationship being a mapping relationship between the preset time period and a range in which the first cable distance is located; and determining the corresponding preset time period according to the first time mapping relationship and the first cable distance.

[0010] In some embodiments, determining the first delay time according to at least the first cable distance comprises: obtaining a second time mapping relationship, the second time mapping relationship being a mapping relationship between the first delay time and a range in which the first cable distance is located; and determining the corresponding first delay time according to the second time mapping relationship and the first cable distance.

[0011] In some embodiments, determining the first delay time according to at least the first cable distance comprises: determining the first delay time according to t = L / v, where t is the first delay time, v is a propagation speed of a signal of the first controller in the cable, and L is the first cable distance.

[0012] According to some embodiments of the present application, another aspect of the embodiments of the present application provides a clock synchronization method of an energy storage system, applied to a second controller in the energy storage system, a first controller and one of all the second controllers in the energy storage system are electrically connected by a cable, the second controller electrically connected with the first controller and other second controllers are connected in series by the cable, the first controller and the second controller have the same structure, the first controller includes a digital signal processor and a field programmable gate array, the digital signal processor and the field programmable gate array are in bidirectional communication, the field programmable gate array of the first controller and the field programmable gate array of the second controller are electrically connected by the cable, the first controller is used for centralized control of each second controller, and the second controller is used for adjusting the power of the energy storage system, the method comprises the following steps: receiving a first delay time sent by the first controller, and adding a clock of the second controller and the first delay time to realize clock synchronization between the first controller and the second controller closest to the first controller; obtaining a cable length between the second controller and a next second controller to obtain a second cable distance, and determining a second delay time according to at least the second cable distance, the second delay time being a phase difference value between the clock of the second controller and the clock of the next second controller, and the second controller and the next second controller being electrically connected by a cable; and sending the first delay time to the second controller within a preset time period, so that the next second controller adds the clock of the next second controller and the second delay time to realize clock synchronization between the second controller and the next second controller.

[0013] In some embodiments, after the first delay time is sent to the second controller within the preset time period, the method further comprises: receiving a shutdown instruction sent by the first controller, and switching the state of the second controller to a shutdown state, wherein, in the case that there is at least one faulty device in all the second controllers, and the faulty device is the second controller closest to the first controller, the first controller issues a shutdown instruction to other second controllers except the second controller electrically connected to the first controller, to control other second controllers except the second controller electrically connected to the first controller to shut down; in the case that there is at least one faulty device in all the second controllers, and the faulty device is not the second controller closest to the first controller, the first controller issues the shutdown instruction to a target controller to control the target controller to shut down, the target controller being other second controllers except the faulty device and all the second controllers between the faulty device and the first controller.

[0014] In some embodiments, after the first delay time is sent to the next second controller, the method further comprises: receiving a current delay time sent by the first controller, and adding the clock of the second controller to the current delay time, wherein, after a preset time period, the first controller obtains the cable length between the first controller and the second controller closest to the first controller to obtain a current cable distance; in the case that the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference value, the first controller determines that the second controller does not need to be synchronized again, the first cable distance being the cable length between the first controller and the second controller closest to the first controller; in the case that the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference value, the first controller determines the phase difference between the clock of the second controller closest to the first controller and the clock of the first controller according to at least the current cable distance to obtain the current delay time, and sends the current delay time to the second controller within the preset time period.

[0015] In some embodiments, the receiving the first delay time sent by the first controller comprises: receiving the first delay time sent by the first controller within the preset time period; wherein the first controller obtains a first time mapping relationship, the first time mapping relationship being a mapping relationship between the preset time period and a range in which a first cable distance is located, the first cable distance being a cable length between the first controller and the second controller closest to the first controller; the first controller determines a corresponding preset time period according to the first time mapping relationship and the first cable distance; the first controller determines the first delay time according to t=L / v, or the first controller obtains a second time mapping relationship, the second time mapping relationship being a mapping relationship between the first delay time and a range in which the first cable distance is located; the first controller determines a corresponding first delay time according to the second time mapping relationship and the first cable distance, wherein t is the first delay time, v is a signal propagation speed of the first controller in the cable, and L is the first cable distance.

[0016] According to some embodiments of the present application, a further aspect of the embodiments of the present application provides an energy storage converter, comprising: an obtaining unit configured to obtain a cable length between a first controller and a second controller closest to the first controller, to obtain a first cable distance, and to determine a first delay time according to at least the first cable distance, the first delay time being a phase difference value between a clock of the second controller closest to the first controller and a clock of the first controller; and a first processing unit configured to send the first delay time to the second controller within a preset time period, so that the second controller adds the clock of the second controller and the first delay time to achieve clock synchronization between the first controller and the second controller closest to the first controller.

[0017] In some embodiments, the energy storage converter further comprises: a second processing unit configured to, after the first delay time is sent to the second controllers within the preset time period, if there is at least one faulty device in all the second controllers and the faulty device is the second controller closest to the first controller, issue a shutdown instruction to the second controllers other than the second controller electrically connected to the first controller to control the second controllers other than the second controller electrically connected to the first controller to shut down; and a third processing unit configured to, if there is at least one faulty device in all the second controllers and the faulty device is the second controller not closest to the first controller, issue the shutdown instruction to a target controller to control the target controller to shut down, the target controller being the second controller other than the faulty device and all the second controllers between the faulty device and the first controller.

[0018] In some embodiments, the energy storage converter further comprises: a fourth processing unit configured to, after the first delay time is sent to the second controllers within the preset time period, obtain a current cable distance between the first controller and the second controller closest to the first controller after a preset time period; a first determination unit configured to, if an absolute value of a difference between the current cable distance and the first cable distance is less than or equal to a preset difference value, determine that the second controllers do not need to be synchronized again; and a second determination unit configured to, if the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to the preset difference value, determine a difference between a clock of the second controller closest to the first controller and a clock of the first controller according to at least the current cable distance, obtain a current delay time, and send the current delay time to the second controllers within the preset time period, so that the second controllers add the clock of the second controller to the current delay time.

[0019] In some embodiments, the energy storage converter further comprises: a fifth processing unit configured to, before the first delay time is sent to the second controllers within the preset time period, obtain a first time mapping relationship, the first time mapping relationship being a mapping relationship between the preset time period and the first cable distance; and a sixth processing unit configured to determine a corresponding preset time period according to the first time mapping relationship and the first cable distance.

[0020] According to some embodiments of the present application, the energy storage system is provided in another aspect of the present application, comprising: a first controller and a plurality of second controllers, the first controller is electrically connected with one of all the second controllers in the energy storage system by a cable, the second controller electrically connected with the first controller is in series with other second controllers by the cable, the first controller and the second controller are the same structure, the first controller comprises a digital signal processor, a field programmable gate array, and the digital signal processor and the field programmable gate array are in bidirectional communication, the field programmable gate array of the first controller and the field programmable gate array of the first controller are electrically connected by the cable, the first controller is used for centralized control of each second controller, the second controller is used for adjusting the power of the energy storage system, the first controller is used for executing any one of the methods, and each second controller is used for executing any one of the methods.

[0021] The technical scheme provided by the embodiments of the present application has at least the following advantages: the transmission speed of the signal in the cable is much lower than the speed of light, and the specific value depends on the material and structure of the cable. At least according to the first cable distance, the first delay time is determined, and the estimated first delay time of the signal from the first controller to the second controller can be calculated; through such a delay compensation mechanism during the delay, the required first delay time can be automatically calculated and applied according to the length of the cable, and when the signal reaches the second controller, the second controller can receive the signal on time due to the compensation of the advance sending, and synchronization is realized. In the parallel architecture of multiple second controllers, the signal is transmitted from the first controller to the first second controller, from the first second controller to the second second controller, and so on, and all devices can realize accurate clock synchronization. Although the signal transmission delay is increased by using the cable instead of the optical fiber, this problem can be overcome by introducing the delay compensation mechanism. Compared with the optical fiber, the cost of the cable is significantly reduced, thereby solving the problem that the clock synchronization of the first controller and the second controller in the energy storage system of the prior art requires optical fiber electrical connection, resulting in high cost. BRIEF DESCRIPTION OF DRAWINGS

[0022] One or more embodiments are illustrated by way of example in the drawings that are for illustrative purposes only, and not for the purposes of limiting the embodiments, unless otherwise specifically stated in the embodiments, the drawings in the drawings do not constitute proportional limitation; in order to more clearly illustrate the technical schemes of the embodiments or the prior art, the drawings needed in the embodiments will be briefly introduced below, and obviously, the drawings in the following description can also obtain other drawings without creative labor for those skilled in the art.

[0023] Figure 1 A flowchart of a clock synchronization method of a first energy storage system;

[0024] Figure 2 A structural diagram of an energy storage converter;

[0025] Figure 3 A flowchart of a clock synchronization method of a first energy storage system;

[0026] Figure 4 A structural diagram of an energy storage system;

[0027] Figure 5 A schematic diagram of an energy storage system. DETAILED DESCRIPTION

[0028] As can be known from the background art, in the energy storage converter, the architecture of the master and the slave is usually used to realize functions such as distributed control, function division and system expansion, the functions of the master include system control and management, data processing and analysis, user interface and interaction, the functions of the slave include local control and execution and cooperative operation. The master and the slave perform their respective functions in the energy storage converter system, the master is responsible for centralized control, data management and user interaction, and the slave is responsible for specific power conversion and local control. Through the cooperative work of the master and the slave, the energy storage converter system can realize efficient, flexible and reliable operation. In the prior art energy storage system, optical fibers are often used to electrically connect the first controller and the second controller, thereby resulting in high cost. In order to solve the problem that the clock synchronization of the first controller and the second controller in the prior art energy storage system needs optical fiber electrical connection, thereby resulting in high cost, the embodiments of the present application provide a clock synchronization method of an energy storage system, an energy storage converter and an energy storage system.

[0029] In the description of the embodiments of the present application, the technical terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0030] In this document, reference to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combined with other embodiments.

[0031] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent: there is A, there is A and B, and there is B. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0032] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0033] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0034] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0035] In the corresponding drawings of the embodiments of the present application, in order to better understand and facilitate the description, the thickness and area of the layer are enlarged. When describing that a component (such as a layer, a film, a region or a substrate) is on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing that a component is on the surface of another component or a component surface is formed or provided with another component, it means that there is no third component between the two components. In addition, when describing that a component is "formed" on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on the edge of the entire surface.

[0036] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise specified, other components are not excluded and can be further included. In addition, when a layer, film, region, plate, or the like is referred to as "on / under" another component, it can be "directly on" the other component (i.e., between the other component and the surface of the other component, no other component is present), or another component can be present therebetween. In addition, when a layer, film, region, plate, or the like is "directly on" another component, or when a layer, film, region, plate, or the like is on the surface of another component, it means that no other component is present therebetween.

[0037] The terms used in the description of various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of various embodiments described and the appended claims, "the aforementioned parts" is also intended to include the plural form, unless the context clearly indicates otherwise. Among them, the components include layers, films, regions, or plates and the like.

[0038] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present application, many technical details are presented in order to enable the reader to better understand the present application. However, the technical solutions claimed by the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0039] The present application provides a clock synchronization method of an energy storage system, applied to a first controller in the energy storage system, the first controller is electrically connected to one of all second controllers in the energy storage system by a cable, the second controller electrically connected to the first controller is connected to other second controllers by the cable, the first controller and the second controller have the same structure, the first controller includes a digital signal processor and a field programmable gate array, the digital signal processor and the field programmable gate array communicate with each other, the field programmable gate array of the first controller is electrically connected to the field programmable gate array of the first controller by the cable, the first controller is used to control the second controllers, and the second controller is used to adjust the power of the energy storage system, as shown in the figure, the method comprises: Figure 1 As shown in the figure, the method comprises:

[0040] In step S101, the length of the cable between the first controller and the second controller closest to the first controller is obtained, the first cable distance is obtained, and the first delay time is determined according to at least the first cable distance, the first delay time is the phase difference between the clock of the second controller closest to the first controller and the clock of the first controller;

[0041] Step S102, the first delay time is sent to the second controller within a preset time period, so that the second controller adds the clock of the second controller to the first delay time, to realize the clock synchronization between the first controller and the second controller closest to the first controller.

[0042] In the above step, the transmission speed of the signal in the cable is much lower than the speed of light, and the specific value depends on the material and structure of the cable. At least according to the first cable distance, the first delay time is determined, and the estimated first delay time of the signal from the first controller to the second controller can be calculated; through the delay compensation mechanism of such a delay, the required first delay time can be automatically calculated and applied according to the length of the cable, and when the signal reaches the second controller, the second controller can receive the signal on time due to the compensation of the advance sending, and synchronization is realized. In the parallel architecture of multiple second controllers, the signal is transmitted from the first controller to the first second controller, from the first second controller to the second second controller, and so on, and all devices can realize accurate clock synchronization. Although the signal transmission delay will increase by using the cable instead of the optical fiber, this problem can be overcome by introducing the delay compensation mechanism. Compared with the optical fiber, the cost of the cable is significantly reduced, thereby solving the problem that the clock synchronization of the first controller and the second controller in the energy storage system of the prior art requires optical fiber electrical connection, resulting in high cost.

[0043] In some embodiments, after the first delay time is sent to the second controller within a preset time period, the method further comprises: in the case that there is at least one faulty device in all the second controllers, and the faulty device is the second controller closest to the first controller, issuing a shutdown instruction to other second controllers except the second controller electrically connected to the first controller, to control other second controllers except the second controller electrically connected to the first controller to shut down; in the case that there is at least one faulty device in all the second controllers, and the faulty device is not the second controller closest to the first controller, issuing the shutdown instruction to the target controller to control the target controller to shut down, the target controller being other second controllers except the faulty device and all the second controllers between the faulty device and the first controller.

[0044] The application also provides a specific use scenario of the processing flow of the faulty device: in a large distributed photovoltaic power station, multiple PCSs (energy storage converters) are connected to each other through cables to form a highly coordinated group. Carrier wave synchronization and interruption synchronization are needed between these converters to ensure the uniformity of power conversion and the stability of the power grid. The control system of the power station consists of a master (first controller) and multiple slaves (second controllers), and the master is responsible for monitoring and managing the operating state of the entire PCS group.

[0045] Specific process: when the system monitoring finds that the slave (second controller) closest to the master has failed, the master immediately recognizes this situation. Taking into account the cable transmission and signal delay factors, the master will send a shutdown instruction to all slaves except the closest slave, ensuring that these devices will not be affected by the faulty slave's false signals and will not produce uncoordinated actions, thereby avoiding the entire system from falling into chaos. If the faulty device is not the slave closest to the master, but is located anywhere else in the system, the master adopts a more delicate strategy. It only sends a shutdown instruction to the target controller, i.e., all slaves except the faulty device and all slaves between the faulty device and the master. In this way, the system can minimize the impact of the faulty device on the overall operation of the system and maintain the maximum range of system functions.

[0046] The beneficial effects of a specific use scenario of the processing flow of the faulty device: by quickly isolating the faulty device and controlling the affected devices to shut down, the propagation of faulty signals can be effectively prevented, and system-level instability or safety accidents can be avoided. This is particularly important for large power facilities such as photovoltaic power stations, as any small failure can lead to serious consequences; while isolating the faulty device, the system can maintain the normal operation of most other devices, reducing unnecessary energy loss and avoiding economic losses caused by the complete shutdown of the system. In particular, for devices that are not directly affected by the faulty device, continuing to operate can ensure the continuity of power supply and economic benefits; shutting down only the affected devices means that the fault area is clearly defined, making it easy for maintenance personnel to quickly locate the fault point and repair it. This method simplifies the fault recovery process, shortens the time for the system to return to normal operation, and improves maintenance efficiency; in the case of partial device shutdown, the system can automatically adjust the load distribution of the remaining devices to ensure that the overall output power is as close as possible to the predetermined target, optimizing the use efficiency of resources, especially in emergency situations, this dynamic scheduling capability is particularly important; when the system is expanded or the device layout changes, this hierarchical fault management mechanism allows the system to make local adjustments or repairs without affecting most devices, enhancing the adaptability and flexibility of the system in a dynamic environment.

[0047] In some embodiments, after the first delay time is sent to the second controller within the preset time period, the method further comprises: obtaining a current cable distance between the first controller and the second controller closest to the first controller after the preset time period; determining that the second controller does not need to be synchronized again if the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference; and determining a current delay time between the clock of the second controller closest to the first controller and the clock of the first controller according to the current cable distance, and sending the current delay time to the second controller within the preset time period, so that the second controller adds the clock of the second controller to the current delay time.

[0048] The preset difference value is determined by reference to the following: assuming that the system requires a clock synchronization accuracy of 10 microseconds, the signal transmission speed in the copper cable is 200,000 kilometers per second (about 67% of the speed of light), and the cable length measurement error is 0.1 meters. According to the formula t = L / v for calculating the signal transmission time, it can be calculated that a 1-meter change in cable length results in a signal transmission time change of about 5 microseconds. Considering the measurement error and system stability, the preset difference value can be set to 2 meters, which ensures that even if the cable length changes by 2 meters, the signal delay change will not exceed the system required clock synchronization accuracy, while avoiding too frequent signal delay adjustment.

[0049] The application also provides a specific use scenario that ignores the influence of cable length. In a certain energy storage system, the master (first controller) and slave (second controller) need to be synchronized by a carrier signal to ensure that the power conversion operations of all PCS devices remain consistent. The cable length between the master and the slave is originally fixed, but during system maintenance or expansion, the cable length may be adjusted. For example, in order to optimize the system layout or add more devices, the cable may be shortened or lengthened.

[0050] Specific operating procedures: Upon system startup or initial cable length setting, the host reads and stores the cable length information (first cable distance) and calculates the signal transmission delay (first delay time) based on the cable length. This delay time is then sent to the slave device, which adjusts its clock accordingly. After the system has been running for a period of time, the host periodically (e.g., every 24 hours or less) re-detects the cable length (current cable distance). If the difference between the current cable distance and the stored first cable distance is less than or equal to a preset difference (e.g., a preset difference of 3 meters, meaning the change in cable length has a negligible impact on signal delay), the system determines that resynchronization is unnecessary because the change in cable length does not significantly affect signal transmission delay. If the difference between the current cable distance and the first cable distance exceeds the preset difference, the host recalculates the signal transmission delay time (current delay time) and sends it to the slave device. The slave device adjusts its clock signal based on the received current delay time to ensure synchronization with the host's clock.

[0051] The benefits of ignoring the impact of cable length in a specific application scenario: Dynamically monitoring changes in cable length and automatically adjusting clock synchronization allows the system to adapt to various layout requirements and changing operating environments, improving overall system adaptability and flexibility. When cable length changes are minor, complex clock synchronization readjustments are unnecessary, reducing maintenance and debugging workload and lowering system maintenance costs. Through regular monitoring and timely adjustments when necessary, the system ensures that carrier signal synchronization remains within acceptable error range even with cable length changes, guaranteeing real-time performance and stability. When system expansion is needed, new devices can be quickly connected and synchronized without manually reconfiguring synchronization parameters for all devices, improving the efficiency and convenience of system expansion. Compared to using fiber optics or other high-cost, low-latency transmission media, the dynamic cable length compensation mechanism allows the use of lower-cost cables while maintaining the required synchronization accuracy, achieving an optimal balance between cost and performance.

[0052] In some embodiments, before sending the first delay time to the second controller within a preset time period, the method further includes: obtaining a first time mapping relationship, wherein the first time mapping relationship is a mapping relationship between the preset time period and the range of the first cable distance; and determining the corresponding preset time period based on the first time mapping relationship and the first cable distance.

[0053] Specifically, there is a direct relationship between cable length and signal transmission delay. By establishing a mapping relationship, the system can accurately calculate the signal transmission delay according to different cable lengths, thereby more accurately adjusting the preset time period and ensuring high precision of clock synchronization between devices. This is crucial for power electronic devices that require precise control of signal phase and frequency. When the cable in the system changes due to device addition, layout adjustment, or maintenance needs, quickly adjusting the preset time period through the mapping relationship can ensure that the system can maintain stable synchronization even in the case of cable length changes. This dynamic adjustment capability enables the system to adapt to changing operating environments, improving overall flexibility and adaptability. During the system design phase, by establishing a mapping relationship, the required preset time period under different cable lengths can be calculated in advance, reducing the need for complex system synchronization circuitry. This method simplifies system design, reduces research and development costs and design cycles, and also reduces the need for real-time computing resources during system operation. Small changes in cable length can result in significant differences in signal delay, which can affect system synchronization performance. By adjusting the preset time period through the mapping relationship in a timely manner, synchronization errors caused by cable length changes can be effectively avoided, reducing system failure rates and improving overall operational reliability. When determining the preset time period, the system can allocate resources for signal processing and data transmission based on the mapping relationship between cable actual length and time delay, avoiding resource waste while ensuring efficient execution of critical synchronization operations. The existence of the mapping relationship allows the system to automatically adapt to cable length changes, reducing the amount of system maintenance and debugging work caused by cable length changes. This not only saves maintenance time but also reduces maintenance costs, improving system maintainability and long-term economic benefits.

[0054] In some embodiments, the first delay time is determined according to at least the first cable distance, including: obtaining a second time mapping relationship, the second time mapping relationship being a mapping relationship of the first delay time and a range in which the first cable distance is located; and determining the corresponding first delay time according to the second time mapping relationship and the first cable distance.

[0055] Specifically, the second time mapping relationship encompasses multiple variables that affect signal transmission, making the calculation of delay time more detailed and closer to the actual value. For example, under the same cable length, the influence of different temperature conditions on signal transmission speed can be taken into account, resulting in a more accurate delay time. By considering various factors, including environmental factors and cable characteristics, the system can better resist the impact of external condition fluctuations and ensure stability under different operating conditions. This is particularly important in scenarios with large climate changes or harsh working environments. The second time mapping relationship allows the system to automatically adjust the delay time based on real-time cable characteristics and environmental conditions without human intervention. This automated adaptive capability greatly improves the operational convenience and efficiency of power electronic systems that require long-term stable operation. During the initial design of the system, designers can use the second time mapping relationship to make more accurate timing planning and circuit design, ensuring the coordinated operation of all devices under different operating conditions and avoiding design flaws caused by inaccurate signal delay estimation. Delay time adjustment based on the second time mapping relationship reduces uncertainty during the debugging process, and the system can enter a stable operating state more quickly after deployment. In addition, since the system can adapt to environmental changes, maintenance workload and time are also reduced.

[0056] Other factors determine the first delay time in combination with cable length: temperature influence: temperature changes can affect the dielectric constant of cable materials, thereby affecting signal transmission speed. When determining the first delay time, real-time temperature data collected by temperature sensors can be combined to adjust the impact of cable length on delay time through table lookup or function calculation. Cable type and material: different types (such as coaxial, twisted pair, optical fiber) and materials of cables have a significant impact on signal transmission speed. In the second time mapping relationship, the relationship between different types of cables and delay time can be included to accurately calculate the delay according to different cable types. Signal frequency: high-frequency signal transmission decays more severely in the cable than low-frequency signal, which can cause changes in delay time. Therefore, when determining the first delay time, the signal frequency variable can also be considered, especially when the system operates in different frequency modes. Cable aging degree: over time, cables may naturally age, causing their characteristics to change and affecting signal transmission. By regularly testing the impedance and delay characteristics of the cable and updating the mapping relationship, the delay time changes caused by cable aging can be compensated. Electromagnetic interference: external electromagnetic interference can affect signal transmission, causing additional delay. Adding the relationship between EMI level and delay time in the second time mapping relationship allows the system to maintain good synchronization performance in strong EMI environments.

[0057] In some embodiments, the first delay time is determined according to at least the first cable distance, including: determining the first delay time according to t = L / v, where t is the first delay time, v is a signal propagation speed of the first controller in the cable, and L is the first cable distance.

[0058] Specifically, the formula t = L / v is based on the propagation theory of electromagnetic waves in a medium, and the application of this formula ensures the scientificity and accuracy of signal transmission delay calculation. The propagation speed v of electromagnetic waves is not only related to the physical properties of the medium, such as the permittivity and permeability of the cable, but also affected by environmental factors such as temperature and humidity. Understanding and applying these theories helps to more accurately estimate signal delay. Through this formula, the cable length L can be directly converted into the delay time t of signal transmission without complex simulation or experimental testing. This simplifies the calculation of delay time in the system design and debugging process, reducing development costs. In a multi-machine synchronization system, accurate calculation of signal delay is crucial for achieving synchronization between devices. Using the formula t = L / v ensures that the signal delay received by each slave controller is accurately calculated based on the actual cable length between it and the master controller, thereby improving the synchronization accuracy of the entire system and ensuring the stability and efficiency of system performance. During system operation, the cable length may change due to device layout adjustment, fault repair, or system expansion. Through the formula t = L / v, the system can quickly respond to changes in cable length, recalculate signal delay, and ensure dynamic adjustment of synchronization between devices, enhancing the flexibility and adaptability of the system.

[0059] According to some embodiments of the present application, a further aspect of the embodiments of the present application provides an energy storage converter, as shown in Figure 2 including:

[0060] The acquisition unit 21 is configured to acquire the cable length between the first controller and the second controller closest to the first controller, obtain a first cable distance, and determine a first delay time according to at least the first cable distance, where the first delay time is the phase difference between the clock of the second controller closest to the first controller and the clock of the first controller.

[0061] The first processing unit 22 is configured to send the first delay time to the second controller within a preset time period, so that the second controller adds the clock of the second controller to the first delay time to achieve synchronization between the clock of the first controller and the clock of the second controller closest to the first controller.

[0062] The energy storage converter can ensure that the signal transmission delay between the second controller and the first controller is accurately calculated and compensated by obtaining the first cable distance and determining the first delay time accordingly. This enables the second controller to accurately adjust its clock phase and keep synchronization with the first controller, thereby optimizing the coordination of signals and the power conversion process in the system and improving the overall efficiency of the system. In a multi-controller parallel system, poor clock synchronization can cause signal inconsistency, which in turn can cause power conversion imbalance or voltage and current fluctuations. The synchronization mechanism using the first cable distance and the first delay time can effectively prevent these problems and ensure stable system operation, avoiding system failure or safety hazards caused by signal coordination errors. In the system design phase, the traditional method of estimating signal delay based on cable length often requires a large number of experimental verification and correction. By directly obtaining the first cable distance and calculating the first delay time through the obtaining unit, system designers can more easily design the clock synchronization circuit, reducing the workload of the debugging stage and speeding up the system development process. In practical applications, cable layout may change due to device location adjustment, system expansion, or fault repair. By sending the first delay time to the second controller within a preset time period through the first processing unit, the system can automatically adapt to changes in cable layout and maintain the continuous effectiveness of clock synchronization between devices. When the system fails, maintenance personnel can quickly locate the problem by checking the cable length and the first delay time without the need for complex signal analysis or circuit diagnosis. During fault recovery, as long as the measurement of the first cable distance is accurate, the clock synchronization can be quickly restored by re-sending the first delay time.

[0063] In some embodiments, the energy storage converter further comprises: a second processing unit configured to, after sending the first delay time to the second controller within a preset time period, in the case that there is at least one faulty device in all the second controllers and the faulty device is the second controller closest to the first controller, issue a shutdown instruction to the second controllers other than the second controller electrically connected to the first controller to control the second controllers other than the second controller electrically connected to the first controller to shut down; and a third processing unit configured to, in the case that there is at least one faulty device in all the second controllers and the faulty device is not the second controller closest to the first controller, issue the shutdown instruction to a target controller to control the target controller to shut down, the target controller being the second controller other than the faulty device and all the second controllers between the faulty device and the first controller.

[0064] The application also provides a specific use scenario of the processing flow of the faulty device: in a large distributed photovoltaic power station, multiple PCSs (energy storage converters) are connected to each other through cables to form a highly coordinated group. Carrier wave synchronization and interruption synchronization are needed between these converters to ensure the uniformity of power conversion and the stability of the power grid. The control system of the power station consists of a master (first controller) and multiple slaves (second controllers), and the master is responsible for monitoring and managing the operating state of the entire PCS group.

[0065] Specific process: when the system monitoring finds that the slave (second controller) closest to the master has failed, the master immediately recognizes this situation. Taking into account the cable transmission and signal delay factors, the master will send a shutdown instruction to all slaves except the closest slave, ensuring that these devices will not be affected by the faulty slave's false signals and will not produce uncoordinated actions, thereby avoiding the entire system from falling into chaos. If the faulty device is not the slave closest to the master, but is located anywhere else in the system, the master adopts a more delicate strategy. It only sends a shutdown instruction to the target controller, i.e., all slaves except the faulty device and all slaves between the faulty device and the master. In this way, the system can minimize the impact of the faulty device on the overall operation of the system and maintain the maximum range of system functions.

[0066] The beneficial effects of a specific use scenario of the processing flow of the faulty device: by quickly isolating the faulty device and controlling the affected devices to shut down, the propagation of faulty signals can be effectively prevented, and system-level instability or safety accidents can be avoided. This is particularly important for large power facilities such as photovoltaic power stations, as any small failure can lead to serious consequences; while isolating the faulty device, the system can maintain the normal operation of most other devices, reducing unnecessary energy loss and avoiding economic losses caused by the complete shutdown of the system. In particular, for devices that are not directly affected by the faulty device, continuing to operate can ensure the continuity of power supply and economic benefits; shutting down only the affected devices means that the fault area is clearly defined, making it easy for maintenance personnel to quickly locate the fault point and repair it. This method simplifies the fault recovery process, shortens the time for the system to return to normal operation, and improves maintenance efficiency; in the case of partial device shutdown, the system can automatically adjust the load distribution of the remaining devices to ensure that the overall output power is as close as possible to the predetermined target, optimizing the use efficiency of resources, especially in emergency situations, this dynamic scheduling capability is particularly important; when the system is expanded or the device layout changes, this hierarchical fault management mechanism allows the system to make local adjustments or repairs without affecting most devices, enhancing the adaptability and flexibility of the system in a dynamic environment.

[0067] In some embodiments, the energy storage converter further comprises: a fourth processing unit configured to, after sending the first delay time to the second controller within the preset time period, obtain a current cable distance between the first controller and the second controller closest to the first controller after a preset time period; a first determining unit configured to, in a case that an absolute value of a difference between the current cable distance and the first cable distance is less than or equal to a preset difference value, determine that the second controller does not need to be synchronized again; and a second determining unit configured to, in a case that the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to the preset difference value, determine a difference between a clock of the second controller closest to the first controller and a clock of the first controller according to at least the current cable distance, obtain a current delay time, and send the current delay time to the second controller within the preset time period, so that the second controller adds the clock of the second controller and the current delay time.

[0068] The application also provides a specific use scenario of ignoring the influence of cable length. In a certain energy storage system, the master (first controller) and the slave (second controller) need to be synchronized by a carrier signal to ensure that the power conversion operations of all PCS devices are consistent. The cable length between the master and the slave is originally fixed, but it may be adjusted during system maintenance or expansion. For example, in order to optimize the system layout or add more devices, the cable may be shortened or lengthened.

[0069] Specific operation process: When the system starts or the cable length is set for the first time, the master reads and stores the length information of the cable (first cable distance), calculates the signal transmission delay (first delay time) according to the cable length, sends the delay time to the slave, and the slave adjusts the clock synchronization according to the received delay time. After the system runs for a period of time, the master re-detects the length of the cable (current cable distance) regularly (for example, every 24 hours or shorter period). If the difference between the current cable distance and the stored first cable distance is less than or equal to a preset difference value (for example, the preset difference value can be 3 meters, which means that the change of the cable length can be ignored), the system determines that it does not need to be synchronized again, because the change of the cable length will not significantly affect the signal transmission delay. If the difference between the current cable distance and the first cable distance exceeds the preset difference value, the master will re-calculate the delay time of the signal transmission (current delay time) and send it to the slave. The slave adjusts its own clock signal according to the received current delay time to ensure that the clock is synchronized with the master.

[0070] A specific use case that ignores the cable length effect: dynamically monitor the cable length changes and automatically adjust the clock synchronization, so that the system can adapt to various arrangement requirements and changes in operating environment, improving the overall adaptability and flexibility of the system. In the case of small changes in cable length, there is no need to re-adjust the complex clock synchronization, reducing the maintenance and debugging workload, and reducing the system maintenance cost. Through regular monitoring and immediate adjustment when necessary, the system can ensure that the synchronization of the carrier signal is still within an acceptable error range in the case of cable length changes, ensuring the real-time and stability of the system operation. When the system needs to be expanded, the new equipment can be quickly connected and synchronized, without the need to manually reconfigure the synchronization parameters of all devices, improving the efficiency and convenience of system expansion. Compared with using optical fiber or other high-cost, low-delay transmission media, the dynamic cable length compensation mechanism allows the use of lower-cost cables while maintaining the required synchronization accuracy of the system, achieving an optimal balance between cost and performance.

[0071] In some embodiments, the above energy storage converter further comprises: a fifth processing unit for obtaining a first time mapping relationship before the first delay time is sent to the second controller within a preset time period, the first time mapping relationship being a mapping relationship between the preset time period and the first cable; a sixth processing unit for determining the corresponding preset time period according to the first time mapping relationship and the first cable distance.

[0072] In particular, there is a direct relationship between cable length and signal transmission delay. By establishing a mapping relationship, the system can accurately calculate the signal transmission delay according to different cable lengths, thereby more accurately adjusting the preset time period and ensuring high precision of clock synchronization between devices. This is crucial for power electronic devices that require precise control of signal phase and frequency. When the cable in the system changes due to device addition, layout adjustment, or maintenance needs, quickly adjusting the preset time period through the mapping relationship can ensure that the system can maintain stable synchronization even in the case of cable length changes. This dynamic adjustment capability enables the system to adapt to changing operating environments, improving overall flexibility and adaptability. During the system design phase, by establishing a mapping relationship, the required preset time period under different cable lengths can be calculated in advance, reducing the need for complex system synchronization circuitry. This method simplifies system design, reduces research and development costs and design cycles, and also reduces the need for real-time computing resources during system operation. Small changes in cable length can result in significant differences in signal delay, which can affect system synchronization performance. By adjusting the preset time period through the mapping relationship in a timely manner, synchronization errors caused by cable length changes can be effectively avoided, reducing system failure rates and improving overall operational reliability. When determining the preset time period, the system can allocate resources for signal processing and data transmission based on the mapping relationship between cable actual length and time delay, avoiding resource waste while ensuring efficient execution of critical synchronization operations. The existence of the mapping relationship allows the system to automatically adapt to cable length changes, reducing the amount of system maintenance and debugging work caused by cable length changes. This not only saves maintenance time but also reduces maintenance costs, improving system maintainability and long-term operational economic benefits.

[0073] In some embodiments, the acquisition unit further includes: an acquisition module for acquiring a second time mapping relationship, the second time mapping relationship being a mapping relationship for the first delay time and the range of the first cable distance; and a first determination module for determining the corresponding first delay time according to the second time mapping relationship and the first cable distance.

[0074] Specifically, the second time mapping relationship encompasses multiple variables that affect signal transmission, which makes the calculation of delay time more detailed and closer to the actual value. For example, under the same cable length, the influence of different temperature conditions on signal transmission speed can be taken into account, resulting in a more accurate delay time. By considering various factors, including environmental factors and cable characteristics, the system can better withstand the impact of external condition fluctuations and ensure stability under different operating conditions. This is particularly important in scenarios where the climate changes greatly or the working environment is harsh. The second time mapping relationship allows the system to automatically adjust the delay time based on real-time cable characteristics and environmental conditions without human intervention. This automated adaptive capability greatly improves the operational convenience and efficiency of power electronic systems that need to operate stably for a long time. During the initial design of the system, designers can use the second time mapping relationship to make more accurate timing planning and circuit design, ensuring the coordinated operation of all devices under different operating conditions and avoiding design flaws caused by inaccurate signal delay estimation. Delay time adjustment based on the second time mapping relationship reduces uncertainty during the debugging process, and the system can enter a stable operating state more quickly after deployment. In addition, since the system can adapt to environmental changes, maintenance workload and time are also reduced.

[0075] In some embodiments, the acquisition unit further includes a second determination module configured to determine the first delay time according to t = L / v, where t is the first delay time, v is the propagation speed of the signal of the first controller in the cable, and L is the first cable distance.

[0076] According to some embodiments of the present application, another aspect of the embodiments of the present application provides a clock synchronization method of an energy storage system. The method is applied to a second controller in the energy storage system. A first controller is electrically connected to one of all second controllers in the energy storage system through a cable. The second controller electrically connected to the first controller is connected to other second controllers through the cable. The first controller and the second controller have the same structure. The first controller includes a digital signal processor and a field programmable gate array. The digital signal processor and the field programmable gate array communicate with each other. The field programmable gate array of the first controller is electrically connected to the field programmable gate array of the second controller through the cable. The first controller is used to centrally control the second controllers. The second controller is used to adjust the power of the energy storage system, as shown in the figure. The method includes: Figure 3

[0077] ​Step S301, receiving the first delay time sent by the first controller, and adding the clock of the second controller to the first delay time to achieve the clock synchronization between the first controller and the second controller closest to the first controller;

[0078] Step S302, obtaining the cable length between the second controller and the next second controller to obtain the second cable distance, and determining the second delay time according to at least the second cable distance, the second delay time being the phase difference value between the clock of the second controller and the clock of the next second controller, and the second controller and the next second controller being electrically connected by a cable;

[0079] Step S303, sending the first delay time to the second controller within a preset time period, so that the next second controller adds the clock of the next second controller to the second delay time to achieve the clock synchronization between the second controller and the next second controller.

[0080] The principle of the second delay time is the same as that of the first delay time, and thus will not be described here.

[0081] In the above steps, the transmission speed of the signal in the cable is much lower than the speed of light, and the specific value depends on the material and structure of the cable. At least according to the first cable distance, the first delay time is determined, and the estimated first delay time of the signal from the first controller to the second controller can be calculated. Through such a delay compensation mechanism during the delay time, the required first delay time can be automatically calculated and applied according to the length of the cable. When the signal reaches the second controller, the second controller can receive the signal on time due to the compensation sent in advance, and synchronization is achieved. In the parallel architecture of multiple second controllers, the signal is transmitted from the first controller to the first second controller, from the first second controller to the second second controller, and so on, and all devices can achieve precise clock synchronization. Although the signal transmission delay will increase by using the cable instead of the optical fiber, this problem can be overcome by introducing the delay compensation mechanism. Compared with the optical fiber, the cost of the cable is significantly reduced, thereby solving the problem of high cost caused by the optical fiber electrical connection required for the clock synchronization of the first controller and the second controller in the energy storage system of the prior art.

[0082] In some embodiments, after sending the first delay time to the second controller within the preset time period, the method further comprises: receiving a shutdown instruction sent by the first controller, and switching the state of the second controller to a shutdown state; wherein, when there is at least one faulty device in all the second controllers, and the faulty device is the second controller closest to the first controller, the first controller issues a shutdown instruction to the second controllers other than the second controller electrically connected to the first controller, to control the second controllers other than the second controller electrically connected to the first controller to shut down; when there is at least one faulty device in all the second controllers, and the faulty device is not the second controller closest to the first controller, the first controller issues the shutdown instruction to the target controller to control the target controller to shut down, and the target controller is the second controller other than the faulty device and all the second controllers between the faulty device and the first controller.

[0083] Specifically, by quickly isolating the faulty device and controlling the affected devices to shut down, the propagation of the fault signal can be effectively prevented, and system-level instability or safety accidents can be avoided. This is particularly important for large power facilities such as photovoltaic power stations, because any small fault can lead to serious consequences; while the faulty device is isolated, the system can maintain the normal operation of most other devices, reducing unnecessary energy loss and avoiding economic losses caused by system-wide shutdown. In particular, for devices that are not directly affected by the faulty device, continuing to operate can ensure the continuity of power supply and economic benefits; only shutting down the affected devices means that the fault area is clearly defined, facilitating maintenance personnel to quickly locate the fault point and repair. This method simplifies the fault recovery process, shortens the time for the system to return to normal operation, and improves maintenance efficiency; in the case of partial device shutdown, the system can automatically adjust the load distribution of the remaining devices to ensure that the overall output power is as close as possible to the predetermined target, optimizing the use efficiency of resources, especially in emergency situations, this dynamic scheduling capability is particularly important; when the system is expanded or the device layout is changed, this hierarchical fault management mechanism allows the system to make local adjustments or repairs without affecting most devices, enhancing the adaptability and flexibility of the system in a dynamic environment.

[0084] In some embodiments, after the first delay time is sent to the next second controller, the method further comprises: receiving a current delay time sent by the first controller, adding the clock of the second controller to the current delay time, wherein the first controller obtains the cable length between the first controller and the second controller closest to the first controller after a preset time period, to obtain a current cable distance; in the case that the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference value, the first controller determines that it is not necessary to synchronize the second controller again, and the first cable distance is the cable length between the first controller and the second controller closest to the first controller; in the case that the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference value, the first controller determines the phase difference between the clock of the second controller closest to the first controller and the clock of the first controller according to at least the current cable distance, to obtain the current delay time, and sends the current delay time to the second controller within the preset time period.

[0085] Specifically, the dynamic monitoring of the cable length change and the automatic clock synchronization adjustment enable the system to adapt to various arrangement requirements and operating environment changes, thereby improving the overall adaptability and flexibility of the system. In the case of small cable length change, complex clock synchronization adjustment does not need to be performed again, thereby reducing the maintenance and debugging workload and lowering the system maintenance cost. Through regular monitoring and immediate adjustment when necessary, the system can ensure that the synchronization of the carrier signal is still within an acceptable error range in the case of cable length change, thereby ensuring the real-time performance and stability of the system operation. When the system needs to be expanded, the newly added equipment can be quickly connected and adjusted, without the need to manually reconfigure the synchronization parameters of all the equipment, thereby improving the efficiency and convenience of system expansion. Compared with the use of optical fiber or other high-cost and low-delay transmission media, the dynamic cable length compensation mechanism allows the use of lower-cost cables while maintaining the required synchronization accuracy of the system, thereby achieving an optimal balance between cost and performance.

[0086] In some embodiments, the receiving the first delay time sent by the first controller comprises: receiving the first delay time sent by the first controller within the preset time period; wherein the first controller obtains a first time mapping relationship, the first time mapping relationship is a mapping relationship between the preset time period and a range in which a first cable distance is located, the first cable distance is a cable length between the first controller and a second controller closest to the first controller; the first controller determines the corresponding preset time period according to the first time mapping relationship and the first cable distance; the first controller determines the first delay time according to t = L / v, or the first controller obtains a second time mapping relationship, the second time mapping relationship is a mapping relationship between the first delay time and a range in which the first cable distance is located; the first controller determines the corresponding first delay time according to the second time mapping relationship and the first cable distance, wherein t is the first delay time, v is a signal propagation speed of the first controller in the cable, and L is the first cable distance.

[0087] Specifically, there is a direct relationship between cable length and signal transmission delay. By establishing a mapping relationship, the system can accurately calculate the signal transmission delay according to different cable lengths, thereby more accurately adjusting the preset time period and ensuring high precision of clock synchronization between devices. The second time mapping relationship covers multiple variables that affect signal transmission, which makes the calculation of delay time more detailed and closer to the actual value. For example, under the same cable length, the influence of different temperature conditions on signal transmission speed can be taken into account to obtain a more accurate delay time. The formula t = L / v is based on the propagation theory of electromagnetic waves in medium, and the application of this formula ensures the scientificity and accuracy of signal transmission delay calculation. The propagation speed v of electromagnetic waves is not only related to the physical properties of the medium, such as the dielectric constant and magnetic permeability of the cable, but also affected by environmental factors such as temperature and humidity. Understanding and applying these theories helps to more accurately estimate signal delay.

[0088] According to some embodiments of the present application, in a further aspect, the present application provides a power storage system, such as Figure 4As shown, the energy storage system comprises a first controller and a plurality of second controllers (i.e., second controller 1 to second controller n), the first controller is electrically connected to one of all the second controllers in the energy storage system by a cable, the second controller electrically connected to the first controller is in series connection with other second controllers by the cable, the first controller and the second controller are of the same structure, the first controller comprises a digital signal processor, a field programmable gate array, and the digital signal processor (DSP) and the field programmable gate array (FPGA) are in bidirectional communication, the field programmable gate array of the first controller is electrically connected to the field programmable gate array of the second controller by the cable, the first controller is used for centralized control of each second controller, the second controller is used for adjusting the power of the energy storage system, and the first controller is used for executing any of the methods, and each second controller is used for executing any of the methods.

[0089] In the energy storage system, the transmission speed of signals in the cable is much lower than the speed of light, and the specific value depends on the material and structure of the cable. At least according to the first cable distance, a first delay time is determined, and an estimated first delay time of signal transmission from the first controller to the second controller can be calculated; through such a delay compensation mechanism during delay, the required first delay time can be automatically calculated and applied according to the length of the cable, and when the signal reaches the second controller, the second controller can receive the signal on time due to the compensation of the advance sending, realize synchronization, and in the parallel architecture of multiple second controllers, the signal is transmitted from the first controller to the first second controller, from the first second controller to the second second controller, and so on, and all devices can realize accurate clock synchronization. Although the signal transmission delay will increase by using the cable instead of the optical fiber, this problem can be overcome by introducing the delay compensation mechanism. Compared with the optical fiber, the cost of the cable is significantly reduced, thereby solving the problem that the clock synchronization of the first controller and the second controller in the energy storage system in the prior art requires optical fiber electrical connection, resulting in high cost.

[0090] As shown in Figure 5 The working principle of the energy storage system is shown: the energy storage system comprises a host and a plurality of slaves (slave 1, slave 2, …, slave n), the host and the slaves each comprise an ARM, a DSP and an FPGA, the ARM and the FPGA are in bidirectional communication, the FPGA and the DSP are in bidirectional communication, the ARM and the DSP do not directly communicate, and data transmission between the ARM and the DSP needs to be realized via the FPGA. The application realizes signal transmission in a step-by-step transmission manner, as shown in Figure 5The dashed line in the figure indicates that the master FPGA transmits the synchronization signal to the first slave FPGA, the first slave FPGA transmits the synchronization signal to the second slave FPGA, and so on. Each FPGA synchronizes the received synchronization signal to the local DSP.

[0091] DSP (Digital Signal Processor) is a processor that processes digital signals. The FPGA (Field-Programmable Gate Array) is used to synchronize the clock of the DSP. In high-speed signal transmission scenarios such as FPGA clock synchronization, the high-speed data processing capability of the FPGA can ensure that the signal will not have delay accumulation or distortion during transmission. ARM is used to provide various cable distances.

[0092] ARM (Advanced RISC Machine) is a processor architecture widely used in mobile phones, tablets, embedded systems and other devices. It is based on the design of a reduced instruction set computer, with high energy efficiency and good performance.

[0093] DSP (Digital Signal Processor) is a processor that processes digital signals. It is commonly used in audio, video, communication and other fields that require fast digital signal processing. Compared with general-purpose processors, DSP has higher processing speed and efficiency, and is suitable for real-time processing tasks.

[0094] FPGA (Field-Programmable Gate Array) is a highly programmable chip that can be configured with different logic functions through hardware description languages such as VHDL or Verilog. The flexibility of FPGA makes it suitable for prototyping, complex computing tasks and applications that require high parallel processing.

[0095] Those skilled in the art can understand that the above embodiments are specific examples of the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. A clock synchronization method for an energy storage system, applied to a first controller in the energy storage system, wherein the first controller is electrically connected to one of all second controllers in the energy storage system via a cable, and the second controller electrically connected to the first controller is connected in series with other second controllers via the cable, the first controller and the second controllers have the same structure, the first controller includes a digital signal processor and a field-programmable gate array (FPGA), the digital signal processor and the FPGA communicate bidirectionally, and the FPGA of the first controller is electrically connected to itself via the cable, the first controller is used to centrally control each of the second controllers, and the second controllers are used to adjust the power of the energy storage system, characterized in that... include: The cable length between the first controller and the second controller closest to the first controller is obtained to obtain a first cable distance, and a first delay time is determined based at least on the first cable distance. The first delay time is the phase difference between the clock of the second controller closest to the first controller and the clock of the first controller. The first delay time is sent to the second controller within a preset time period, so that the second controller adds the clock of the second controller to the first delay time, thereby achieving clock synchronization between the first controller and the second controller closest to the first controller.

2. The clock synchronization method for an energy storage system according to claim 1, characterized in that, After sending the first delay time to the second controller within a preset time period, the method further includes: If at least one of the second controllers is faulty, and the faulty device is the second controller closest to the first controller, a shutdown command is issued to the other second controllers besides the second controller electrically connected to the first controller, so as to control the shutdown of the other second controllers besides the second controller electrically connected to the first controller; If at least one of the faulty devices exists among all the second controllers, and the faulty device is not the second controller closest to the first controller, a shutdown command is issued to the target controller to control the target controller to shut down. The target controller is any other second controller besides the faulty device and all the second controllers between the faulty device and the first controller.

3. The clock synchronization method for an energy storage system according to claim 1, characterized in that, After sending the first delay time to the second controller within a preset time period, the method further includes: After a preset time period, the cable length between the first controller and the second controller closest to the first controller is obtained, and the current cable distance is obtained. If the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference, it is determined that there is no need to synchronize the second controller again; If the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference, at least based on the current cable distance, the difference between the clock of the second controller closest to the first controller and the clock of the first controller is determined to obtain the current delay time, and the current delay time is sent to the second controller within the preset time period so that the second controller adds the clock of the second controller to the current delay time.

4. The clock synchronization method for an energy storage system according to claim 1, characterized in that, Before sending the first delay time to the second controller within a preset time period, the method further includes: Obtain the first time mapping relationship, which is the mapping relationship between the preset time period and the range of the first cable distance; The corresponding preset time period is determined based on the first time mapping relationship and the first cable distance.

5. The clock synchronization method for an energy storage system according to claim 1, characterized in that, Determining the first delay time based at least on the first cable distance includes: Obtain a second time mapping relationship, which is a mapping relationship between the first delay time and the range of the first cable distance; The corresponding first delay time is determined based on the second time mapping relationship and the first cable distance.

6. The clock synchronization method for an energy storage system according to claim 1, characterized in that, Determining the first delay time based at least on the first cable distance includes: The first delay time is determined according to t=L / v, where t is the first delay time, v is the propagation speed of the signal from the first controller in the cable, and L is the distance of the first cable.

7. A clock synchronization method for an energy storage system, applied to a second controller in the energy storage system, wherein a first controller is electrically connected to one of all second controllers in the energy storage system via a cable, and the second controller electrically connected to the first controller is connected in series with other second controllers via the same cable, the first controller and the second controllers have the same structure, the first controller includes a digital signal processor and a field-programmable gate array (FPGA), the digital signal processor and the FPGA communicate bidirectionally, and the FPGA of the first controller is electrically connected to itself via the same cable, the first controller is used to centrally control each of the second controllers, and the second controllers are used to adjust the power of the energy storage system, characterized in that... include: The clock of the first controller is received and the clock of the second controller is added to the first delay time to achieve clock synchronization between the first controller and the second controller closest to the first controller. The cable length between the second controller and the next second controller is obtained to obtain the second cable distance, and a second delay time is determined at least based on the second cable distance. The second delay time is the phase difference between the clock of the second controller and the clock of the next second controller. The second controller and the next second controller are electrically connected by a cable. The first delay time is sent to the second controller within a preset time period, so that the next second controller adds the clock of the next second controller to the second delay time, thereby achieving clock synchronization between the second controller and the next second controller.

8. The clock synchronization method for an energy storage system according to claim 7, characterized in that, After sending the first delay time to the second controller within a preset time period, the method further includes: The system receives a shutdown command from the first controller and switches its own state to a shutdown state. If at least one faulty device exists among all the second controllers, and the faulty device is the second controller closest to the first controller, the first controller issues a shutdown command to all other second controllers except those electrically connected to the first controller to control the shutdown of these other second controllers. If at least one faulty device exists among all the second controllers, and the faulty device is not the second controller closest to the first controller, the first controller issues the shutdown command to a target controller to control the shutdown of the target controller. The target controller is any second controller other than the faulty device and all second controllers between the faulty device and the first controller.

9. The clock synchronization method for an energy storage system according to claim 7, characterized in that, After sending the first delay time to the next second controller, the method further includes: The system receives the current delay time sent by the first controller, adds the clock of the second controller to the current delay time, wherein the first controller obtains the cable length between the first controller and the second controller closest to the first controller after a preset time period to obtain the current cable distance; if the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference, the first controller determines that it is not necessary to synchronize the second controller again, where the first cable distance is the cable length between the first controller and the second controller closest to the first controller; if the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to the preset difference, the first controller at least determines the phase difference between the clock of the second controller closest to the first controller and the clock of the first controller based on the current cable distance to obtain the current delay time, and sends the current delay time to the second controller within the preset time period.

10. The clock synchronization method for an energy storage system according to claim 7, characterized in that, Receiving the first delay time sent by the first controller includes: Receive the first delay time sent by the first controller within the preset time period; Wherein, the first controller acquires a first time mapping relationship, which is a mapping relationship between the preset time period and the range of the first cable distance, where the first cable distance is the cable length between the first controller and the second controller closest to the first controller; the first controller determines the corresponding preset time period based on the first time mapping relationship and the first cable distance; the first controller determines the first delay time based on t=L / v, or the first controller acquires a second time mapping relationship, which is a mapping relationship between the first delay time and the range of the first cable distance; the first controller determines the corresponding first delay time based on the second time mapping relationship and the first cable distance, where t is the first delay time, v is the propagation speed of the signal from the first controller in the cable, and L is the first cable distance.

11. An energy storage converter, characterized in that, include: The acquisition unit is configured to acquire the cable length between the first controller and the second controller closest to the first controller, obtain a first cable distance, and determine a first delay time based at least on the first cable distance, wherein the first delay time is the phase difference between the clock of the second controller closest to the first controller and the clock of the first controller; The first processing unit is configured to send the first delay time to the second controller within a preset time period, so that the second controller adds the clock of the second controller to the first delay time, thereby achieving clock synchronization between the first controller and the second controller closest to the first controller; The energy storage converter further includes: a second processing unit, configured to, after sending the first delay time to the second controller within a preset time period, if at least one faulty device exists among all the second controllers, and the faulty device is the second controller closest to the first controller, issue a shutdown command to other second controllers besides the second controller electrically connected to the first controller to control the shutdown of the other second controllers besides the second controller electrically connected to the first controller; and a third processing unit, configured to, if at least one of the faulty devices exists among all the second controllers, and the faulty device is not the second controller closest to the first controller, issue the shutdown command to a target controller to control the shutdown of the target controller, wherein the target controller is other second controllers besides the faulty device and all second controllers between the faulty device and the first controller.

12. The energy storage converter according to claim 11, characterized in that, The energy storage converter also includes: The fourth processing unit is configured to send the first delay time to the second controller within a preset time period, and after a preset time period, obtain the cable length between the first controller and the second controller closest to the first controller to obtain the current cable distance; The first determining unit is configured to determine that, if the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference, it is unnecessary to synchronize the second controller again. The second determining unit is configured to, when the absolute value of the difference between the current cable distance and the first cable distance is less than or equal to a preset difference, at least based on the current cable distance, determine the difference between the clock of the second controller closest to the first controller and the clock of the first controller, obtain the current delay time, and send the current delay time to the second controller within the preset time period, so that the second controller adds the clock of the second controller to the current delay time.

13. The energy storage converter according to claim 11, characterized in that, The energy storage converter also includes: The fifth processing unit is used to obtain a first time mapping relationship before sending the first delay time to the second controller within a preset time period. The first time mapping relationship is the mapping relationship between the preset time period and the first cable. The sixth processing unit is used to determine the corresponding preset time period based on the first time mapping relationship and the first cable distance.

14. An energy storage system, characterized in that, include: The system comprises a first controller and a plurality of second controllers. The first controller is electrically connected to one of all the second controllers in the energy storage system via a cable. The second controller electrically connected to the first controller is connected in series with the other second controllers via the same cable. The first controller and the second controllers have identical structures. The first controller includes a digital signal processor, a field-programmable gate array (FPGA), and a control. The digital signal processor and the FPGA communicate bidirectionally. The FPGA of the first controller is electrically connected to itself via the cable. The first controller is used to centrally control each of the second controllers. The second controllers are used to adjust the power of the energy storage system. The first controller is used to perform the method according to any one of claims 1 to 6. Each of the second controllers is used to perform the method according to any one of claims 7 to 10.

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