Control method and device of charge-discharge circuit, direct current side controller and storage medium

Abstract

The application provides a control method and device of a charge-discharge circuit, a direct-current side controller and a storage medium. The charge-discharge circuit comprises a direct-current side controller and an alternating-current side controller; the method is applied to the direct-current side controller and comprises the following steps: when the charge-discharge circuit is in a discharge mode, obtaining a direct-current current target value and a direct-current current sampling value of the charge-discharge circuit; performing loop control on the direct-current current sampling value according to the direct-current current target value to obtain a grid-connected current given value; sending the grid-connected current given value to the alternating-current side controller through an emergency frame in a preset communication mode, so that the alternating-current side controller controls a grid-connected current sampling value; in the preset communication mode, an emergency frame is inserted every N query frames, and the time interval for the direct-current side controller to send two data frames is the switching requirement time length of the charge-discharge mode of the charge-discharge circuit / (N+1). The application can make the direct-current current of the charge-discharge circuit quickly and stably reach the target value within the switching requirement time.

Description

Technical Field

[0001] This invention relates to the field of charging and discharging circuit technology, and in particular to a control method, device, DC-side controller, and storage medium for a charging and discharging circuit. Background Technology

[0002] The charging and discharging circuit enables bidirectional energy flow between the battery and the power grid, and has two operating modes: discharging mode and charging mode. In discharging mode, the circuit discharges to the grid; in charging mode, it charges the battery. The circuit also features a fast switching function for charging and discharging modes, requiring a switching time of no more than 20ms.

[0003] When the charging / discharging circuit is in discharge mode, the host computer sends the target DC current value to the DC-side controller as the target value for DC current control. However, in discharge mode, the magnitude of the DC current in the charging / discharging circuit is determined by both AC-side and DC-side parameters. Existing technology lacks a control method for the charging / discharging circuit in discharge mode that ensures the DC current stably reaches the target DC current value within the required switching time. Summary of the Invention

[0004] This invention provides a control method, device, DC-side controller, and storage medium for a charging and discharging circuit, to solve the problem that the prior art lacks a control method for a charging and discharging circuit in discharge mode, so that the DC current of the charging and discharging circuit can stably reach the target DC current value within the required switching time.

[0005] In a first aspect, embodiments of the present invention provide a control method for a charging and discharging circuit, the charging and discharging circuit including a DC-side controller and an AC-side controller; the control method is applied to the DC-side controller, and the control method includes:

[0006] When the charging and discharging circuit is in the discharging mode, the target value of the DC current and the sampled value of the DC current of the charging and discharging circuit are obtained.

[0007] Based on the target value of DC current, loop control is performed on the sampled value of DC current to obtain the grid-connected current setpoint;

[0008] The grid-connected current setpoint is sent to the AC-side controller via an emergency frame in the preset communication mode; the grid-connected current setpoint is used to instruct the AC-side controller to control the grid-connected current sample value according to the grid-connected current setpoint.

[0009] In the preset communication mode, an emergency frame is inserted every N query frames. The time interval between two data frames sent by the DC side controller is the charging and discharging mode switching requirement duration of the charging and discharging circuit / (N+1), where N≥1.

[0010] In one possible implementation, loop control is performed on the sampled DC current values ​​based on the target DC current value to obtain the grid-connected current setpoint, including:

[0011] Obtain the difference between the target DC current value and the sampled DC current value;

[0012] Input the difference into the PI controller to obtain the grid-connected current setpoint.

[0013] In one possible implementation, the initial integral value of the PI controller = target DC current value * battery voltage sample value * efficiency of charging / discharging circuit / grid voltage sample value * preset adjustment coefficient.

[0014] In one possible implementation, in the preset communication mode, the communication rate is 38400bps, and both the DC-side controller and the AC-side controller send data frames in a polling manner.

[0015] In one possible implementation, the default communication mode is full-duplex communication.

[0016] In a second aspect, embodiments of the present invention provide a control device for a charging and discharging circuit, the charging and discharging circuit including a DC-side controller and an AC-side controller; the control device is applied to the DC-side controller, and the control device includes:

[0017] The acquisition module is used to acquire the target value of DC current and the sampled value of DC current of the charging and discharging circuit when the charging and discharging circuit is in the discharging mode.

[0018] The loop control module is used to perform loop control on the sampled DC current value according to the target DC current value to obtain the grid-connected current setpoint.

[0019] The transmitting module is used to send the grid-connected current setpoint to the AC-side controller via an emergency frame in a preset communication mode; the grid-connected current setpoint is used to instruct the AC-side controller to control the grid-connected current sample value according to the grid-connected current setpoint.

[0020] In the preset communication mode, an emergency frame is inserted every N query frames. The time interval between two data frames sent by the DC side controller is the charging and discharging mode switching requirement duration of the charging and discharging circuit / (N+1), where N≥1.

[0021] In one possible implementation, the loop control module is specifically used for:

[0022] Obtain the difference between the target DC current value and the sampled DC current value;

[0023] Input the difference into the PI controller to obtain the grid-connected current setpoint.

[0024] Thirdly, embodiments of the present invention provide a DC-side controller, including a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the control method of the charging and discharging circuit as described in the first aspect or any possible implementation thereof.

[0025] Fourthly, embodiments of the present invention provide a charging and discharging circuit, including an AC side controller and a DC side controller as described in the third aspect;

[0026] The DC-side controller and the AC-side controller communicate through a preset communication method.

[0027] Fifthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the control method for the charging and discharging circuit as described in the first aspect or any possible implementation thereof.

[0028] This invention provides a control method, device, DC-side controller, and storage medium for a charging and discharging circuit. The charging and discharging circuit includes a DC-side controller and an AC-side controller. The method is applied to the DC-side controller. When the charging and discharging module is in discharge mode, the method performs loop control on the DC current sample value according to the DC current target value to obtain the grid-connected current setpoint. The grid-connected current setpoint is then sent to the AC-side controller via an emergency frame in a preset communication mode. This allows the AC-side controller to control the grid-connected current sample value according to the grid-connected current setpoint. In the preset communication mode, an emergency frame is inserted every N query frames. The time interval between the DC-side controller sending two data frames is the charging and discharging mode switching requirement duration of the charging and discharging circuit / (N+1), where N≥1. This enables the DC current of the charging and discharging circuit to quickly and stably reach the DC current target value within the switching requirement time. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the charging and discharging circuit provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the control method for the charging and discharging circuit provided in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of another control method for a charging and discharging circuit provided in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the transmission mechanism of existing half-duplex communication methods;

[0034] Figure 5 This is a schematic diagram of the transmission mechanism of the full-duplex communication method provided in the embodiments of the present invention;

[0035] Figure 6 This is a schematic diagram of the host's state machine under the existing half-duplex communication method;

[0036] Figure 7 This is a schematic diagram of the state machine of the slave device under the existing half-duplex communication method;

[0037] Figure 8 This is a schematic diagram of the state machine of the controller for transmitting data in full-duplex communication mode provided in an embodiment of the present invention;

[0038] Figure 9 This is a schematic diagram of the state machine of the controller receiving data in full-duplex communication mode provided in an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of the structure of the control device for the charging and discharging circuit provided in an embodiment of the present invention;

[0040] Figure 11 This is a schematic diagram of the DC-side controller provided in an embodiment of the present invention. Detailed Implementation

[0041] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0043] See Figure 1 The charging and discharging circuit has one end for connecting to the battery and the other end for connecting to the power grid. It may include a DC-DC module and a DC-AC module. The DC-DC module is used to connect to the battery, and the DC-AC module is used to connect to the power grid.

[0044] The charging and discharging circuit also includes a DC-side controller and an AC-side controller, which can communicate with each other via a sequential SCI (Serial Communication Interface). The DC-side controller is used to control the DC-DC module, and the AC-side controller is used to control the DC-AC module.

[0045] The host computer communicates with the DC-side controller via SCI / CAN (Controller Area Network).

[0046] The current used by the charging and discharging circuit at the end connected to the battery is called direct current, and the current used by the charging and discharging circuit at the end connected to the power grid is called grid-connected current.

[0047] In discharge mode, the host computer sends the target DC current value (also called the discharge current target value) to the DC-side controller as the control target value for the DC current. However, the magnitude of the DC current in discharge mode is determined by the load size. In the discharge direction, the grid side is the load, and the grid-connected current is the actual load current. According to the law of conservation of power, the formula for calculating the grid-connected current is as follows:

[0048] Grid-connected current = (DC current * battery voltage) * efficiency of charging / discharging circuit / grid voltage. Wherein, efficiency of charging / discharging circuit = output power of charging / discharging circuit / input power of charging / discharging circuit.

[0049] However, the controlled object is the grid-connected current on the AC side, while the control effect is on the DC side, manifested as whether the DC current has reached the discharge current target value. Communication between the two sides operates in a master-slave mode, transmitting one data frame every 150ms, which is slow and far from meeting the 20ms requirement for charge / discharge switching. If the discharge current target value is converted into the grid-connected current target value before being transmitted to the AC-side controller, the slow communication speed between the front and rear stages will cause the target value received by the AC side to lag, thus affecting the control result. To address this problem, a solution is proposed: transmitting the direction of discharge current change through the I / O pins of the front and rear stage communication.

[0050] Slow communication speed between the front-end and rear-end stages leads to poor discharge current control. Therefore, the direction of discharge current change can be transmitted via I / O pins connected between the front-end and rear-end stages. The DC-side controller compares the target discharge current value with the sampled DC current value. If the sampled DC current value is less than the target discharge current value, it sends a high-level signal to the AC-side controller; otherwise, it sends a low-level signal. Upon receiving the I / O signal, the AC-side controller adjusts the direction of grid current increase / decrease based on the signal level and adjusts the increment / decrease step size according to time requirements.

[0051] This scheme controls the grid-connected current via I / O, achieving a fast and stable target discharge current value, and the implementation process is simple. However, for charging and discharging circuits, there are no idle I / Os available between the preceding and following stages, therefore this scheme cannot be implemented. To address this problem, this invention proposes a control method for charging and discharging circuits, detailed below.

[0052] See Figure 2 The diagram illustrates a flowchart of the control method for a charging and discharging circuit provided in an embodiment of the present invention. The charging and discharging circuit may include a DC-side controller and an AC-side controller, and the DC-side controller may be the main actuator for executing the control method of the charging and discharging circuit.

[0053] See Figure 2 The control method for the above-mentioned charging and discharging circuit includes:

[0054] In S201, when the charging and discharging circuit is in the discharging mode, the target value of the DC current and the sampled value of the DC current of the charging and discharging circuit are acquired.

[0055] When the charging and discharging circuit is in discharge mode, the host computer sends the target DC current value to the DC-side controller. The DC-side controller can use existing methods to sample the actual DC current and obtain the sampled DC current value.

[0056] The DC current target value is the DC current that the charging and discharging circuit needs to control to this target value. The DC current sample value is the DC current value obtained from the current actual sampling.

[0057] In S202, the DC current sample value is controlled by loop control based on the DC current target value to obtain the grid-connected current setpoint.

[0058] In this embodiment, the sampled DC current value is controlled in a loop based on the target DC current value, and the resulting loop output is the grid-connected current setpoint. This grid-connected current setpoint, also known as the target grid-connected current value, can be used as the setpoint for the AC side current loop. The AC side controller needs to control the grid-connected current of the charging and discharging circuit to this setpoint.

[0059] In S203, the grid-connected current setpoint is sent to the AC-side controller via an emergency frame in the preset communication mode; the grid-connected current setpoint is used to instruct the AC-side controller to control the grid-connected current sample value according to the grid-connected current setpoint.

[0060] In the preset communication mode, an emergency frame is inserted every N query frames. The time interval between two data frames sent by the DC side controller is the charging and discharging mode switching requirement duration of the charging and discharging circuit / (N+1), where N≥1.

[0061] The DC-side controller can send the grid-connected current setpoint to the AC-side controller via an emergency frame in a preset communication mode. After receiving the grid-connected current setpoint, the AC-side controller performs loop control on the sampled grid-connected current value based on the setpoint, so that the sampled grid-connected current value changes to match the grid-connected current setpoint.

[0062] Because the preset communication method inserts an emergency frame every N query frames, when the DC-side controller needs to send the grid-connected current setpoint to the AC-side controller, it can directly send this information via the emergency frame. Furthermore, the time interval between the DC-side controller sending two data frames is the required duration of the charging / discharging mode switching of the charging / discharging circuit / (N+1), where N≥1. Therefore, it can be guaranteed that the grid-connected current setpoint is sent to the AC-side controller within the required duration of the charging / discharging mode switching of the charging / discharging circuit, thereby ensuring that the DC current of the charging / discharging circuit reaches the target DC current value within the required duration of the charging / discharging mode switching of the charging / discharging circuit.

[0063] The charging / discharging mode switching requirement time for the charging / discharging circuit refers to the time required for the circuit to complete the switching between charging and discharging modes. This time can be set according to actual needs; for example, it can be the aforementioned 20ms, or other durations such as 30ms, 15ms, etc. N is a positive integer. For example, when N=1, the preset communication method inserts an emergency frame every other query frame, i.e., an emergency frame is inserted between every two query frames, such as... Figure 5 As shown, at this time, the time interval between two data frames sent by the DC-side controller is the charging and discharging mode switching requirement duration of the charging and discharging circuit / 2; when N = 2, the preset communication mode inserts an emergency frame every 2 query frames. At this time, the time interval between two data frames sent by the DC-side controller is the charging and discharging mode switching requirement duration of the charging and discharging circuit / 3, and so on.

[0064] In a preferred embodiment, N = 1.

[0065] In this embodiment, when the charging / discharging module is in discharge mode, loop control is performed on the DC current sample value according to the DC current target value to obtain the grid current setpoint. The grid current setpoint is then sent to the AC side controller via an emergency frame in a preset communication mode. This allows the AC side controller to control the grid current sample value according to the grid current setpoint. In the preset communication mode, an emergency frame is inserted every N query frames. The time interval between the DC side controller sending two data frames is the charging / discharging mode switching requirement time of the charging / discharging circuit / (N+1), where N≥1. This enables the DC current of the charging / discharging circuit to quickly and stably reach the DC current target value within the switching requirement time.

[0066] In some embodiments, S202 may include:

[0067] Obtain the difference between the target DC current value and the sampled DC current value;

[0068] Input the difference into the PI controller to obtain the grid-connected current setpoint.

[0069] See Figure 3 The difference between the target DC current value and the sampled DC current value is obtained by subtracting the sampled DC current value. This difference is then input into the PI controller for PI control, resulting in the grid-connected current setpoint Id. The PI controller is a proportional-integral controller.

[0070] In this embodiment, the target discharge current value is sent from the host computer to the DC-side controller. The DC-side controller performs PI loop control on the DC current based on the target discharge current value. PI loop control ensures that the DC current stably and accurately tracks the target discharge current value. The loop output Id is sent to the AC-side controller via communication between the front and rear stages, serving as the current loop reference for the AC side and controlling the grid-connected current.

[0071] In some embodiments, the initial integral value of the PI controller = target DC current value * battery voltage sample value * efficiency of charging and discharging circuit / grid voltage sample value * preset adjustment coefficient.

[0072] In this embodiment, an initial value is assigned to the integral of the PI controller. This initial value is the initial input value of the integral element of the PI controller, which can be calculated according to the above formula.

[0073] The preset adjustment coefficient can be a value in the range of 0-1. This value is the experimental adjustment coefficient, which ensures that the initial value of the integral will not cause serious overshoot in the loop, and that the time for the grid-connected current to track Id is as short as possible.

[0074] In some embodiments, in a preset communication mode, the communication rate is 38400bps, and both the DC-side controller and the AC-side controller send data frames in a polling manner.

[0075] In some embodiments, the default communication mode is full-duplex communication.

[0076] It should be noted that the preset communication mode can also be a half-duplex communication mode that meets the above requirements (an emergency frame is inserted every N query frames, the time interval between two data frames sent by the DC side controller is the charging and discharging mode switching requirement of the charging and discharging circuit / (N+1), N≥1, etc.), and no specific restrictions are made here.

[0077] In some specific application scenarios, in order to meet the time requirements for rapid switching between charging and discharging, the front-end and back-end communication architecture and communication baud rate also need to be modified accordingly. The modifications are as follows:

[0078] 1) The communication baud rate has been changed from the original 19200bps to 38400bps;

[0079] 2) The communication architecture is changed from half-duplex to full-duplex, and the time interval between two data frames is shortened from 150ms to the charging and discharging mode switching time requirement of the charging and discharging circuit / (N+1); where, if the charging and discharging mode switching time requirement of the charging and discharging circuit is 20ms and N=1, then the time interval between two data frames is shortened to 10ms.

[0080] 3) An emergency frame is inserted every N data frames, and the DC current loop output Id is sent to the AC side controller via the emergency frame.

[0081] The existing half-duplex communication method's transmission mechanism refers to... Figure 4 The transmission mechanism of the full-duplex communication method in this embodiment of the invention refers to... Figure 5 .

[0082] The existing half-duplex communication method is changed to the full-duplex communication method described in this embodiment of the invention. The specific changes are shown in Table 1. The example is given with a charging and discharging mode switching time of 20ms and N=1.

[0083] Table 1 Summary of Changes in Communication Mechanism

[0084]

[0085]

[0086] in, Figure 6 This is the state machine of the host under the existing half-duplex communication mode, namely the state machine of the DC side controller. Figure 7 This is the state machine of the slave device under the existing half-duplex communication mode, that is, the state machine of the AC side controller. Figure 8 This is the state machine of the controller for transmitting data in full-duplex communication mode, as provided in the embodiments of the present invention. Figure 9 This is the state machine of the controller receiving data in full-duplex communication mode provided in the embodiments of the present invention.

[0087] The control method for the charging and discharging circuit provided in this embodiment of the invention uses a DC-side controller to perform PI control on the DC current. The loop output is used as the grid-connected current setpoint and transmitted to the AC-side controller through front-end and rear-end communication. The communication architecture between the front-end and rear-end is changed from half-duplex to full-duplex to speed up the baud rate. This ensures that the charging and discharging circuit can quickly and stably reach the target value of the discharge current in the discharge direction. The solution is practical and effective, simple to implement, and does not consume too many resources. It can be used as a reference for other projects.

[0088] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0089] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0090] Figure 10 A schematic diagram of the control device for the charging and discharging circuit provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below:

[0091] The charging and discharging circuit includes a DC-side controller and an AC-side controller. For example... Figure 10 As shown, the control device 30 for the charging and discharging circuit is applied to the DC-side controller. The control device 30 for the charging and discharging circuit includes: an acquisition module 31, a loop control module 32, and a transmission module 33.

[0092] The acquisition module 31 is used to acquire the target value of DC current and the sampled value of DC current of the charging and discharging circuit when the charging and discharging circuit is in the discharging mode.

[0093] The loop control module 32 is used to perform loop control on the DC current sample value according to the DC current target value to obtain the grid-connected current setpoint;

[0094] The sending module 33 is used to send the grid-connected current setpoint to the AC side controller through an emergency frame in a preset communication mode; the grid-connected current setpoint is used to instruct the AC side controller to control the grid-connected current sample value according to the grid-connected current setpoint.

[0095] In the preset communication mode, an emergency frame is inserted every N query frames. The time interval between two data frames sent by the DC side controller is the charging and discharging mode switching requirement duration of the charging and discharging circuit / (N+1), where N≥1.

[0096] In one possible implementation, the loop control module 32 is specifically used for:

[0097] Obtain the difference between the target DC current value and the sampled DC current value;

[0098] Input the difference into the PI controller to obtain the grid-connected current setpoint.

[0099] In one possible implementation, the initial integral value of the PI controller = target DC current value * battery voltage sample value * efficiency of charging / discharging circuit / grid voltage sample value * preset adjustment coefficient.

[0100] In one possible implementation, in the preset communication mode, the communication rate is 38400bps, and both the DC-side controller and the AC-side controller send data frames in a polling manner.

[0101] In one possible implementation, the default communication mode is full-duplex communication.

[0102] Figure 11 This is a schematic diagram of the DC-side controller provided in an embodiment of the present invention. Figure 11 As shown, the DC-side controller 4 in this embodiment includes a processor 40 and a memory 41. The memory 41 stores a computer program 42, and the processor 40 calls and runs the computer program 42 stored in the memory 41 to execute the steps in the control method embodiments of the various charging and discharging circuits described above, for example... Figure 2 S201 to S203 are shown. Alternatively, the processor 40 is used to call and run the computer program 42 stored in the memory 41 to implement the functions of each module / unit in the above-described device embodiments, for example... Figure 10 The functions of modules / units 31 to 33 shown.

[0103] For example, the computer program 42 can be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 42 in the DC-side controller 4. For example, the computer program 42 can be divided into... Figure 10 Modules / units 31 to 33 are shown.

[0104] The DC-side controller 4 may be a device such as a DSP. The DC-side controller 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that... Figure 11 This is merely an example of the DC-side controller 4 and does not constitute a limitation on the DC-side controller 4. It may include more or fewer components than shown, or combine certain components, or different components. For example, the DC-side controller may also include input / output devices, network access devices, buses, etc.

[0105] The processor 40 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0106] The memory 41 can be an internal storage unit of the DC-side controller 4, such as a hard disk or RAM of the DC-side controller 4. The memory 41 can also be an external storage device of the DC-side controller 4, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the DC-side controller 4. Furthermore, the memory 41 can include both internal storage units and external storage devices of the DC-side controller 4. The memory 41 is used to store the computer program and other programs and data required by the DC-side controller. The memory 41 can also be used to temporarily store data that has been output or will be output.

[0107] Corresponding to the DC-side controller described above, this embodiment of the invention also provides a charging and discharging circuit, including an AC-side controller and a DC-side controller as described above;

[0108] The DC-side controller and the AC-side controller communicate through a preset communication method.

[0109] For a detailed description of the charging and discharging circuit, please refer to the foregoing description, which will not be repeated here.

[0110] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0111] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0112] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0113] In the embodiments provided by this invention, it should be understood that the disclosed device / DC-side controller and method can be implemented in other ways. For example, the device / DC-side controller embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0114] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0115] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0116] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the control methods for the various charging and discharging circuits described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0117] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A control method of a charge-discharge circuit, characterized by, The charging and discharging circuit comprises a direct current side controller and an alternating current side controller; the control method is applied to the direct current side controller, and the control method comprises the following steps: When the charging and discharging circuit is in a discharging mode, a direct current target value and a direct current sampling value of the charging and discharging circuit are obtained; According to the direct current target value, loop control is performed on the direct current sampling value to obtain a grid-connected current given value; The grid-connected current given value is sent to the alternating current side controller through an emergency frame in a preset communication mode; the grid-connected current given value is used to instruct the alternating current side controller to control a grid-connected current sampling value according to the grid-connected current given value; the preset communication mode is a full-duplex communication mode; In the preset communication mode, one emergency frame is inserted every N query frames, and a time interval for the direct current side controller to send two data frames is a charging and discharging mode switching requirement time length of the charging and discharging circuit / (N+1), N≥1; In the preset communication mode, the direct current side controller and the alternating current side controller both send data frames in a polling mode.

2. The control method of the charge and discharge circuit according to claim 1, characterized by, The loop control comprises the following steps: A difference value between the direct current target value and the direct current sampling value is obtained; The difference value is input into a PI controller to obtain the grid-connected current given value.

3. The control method of the charge and discharge circuit according to claim 2, characterized by, An integral quantity initial value of the PI controller is equal to the direct current target value* a battery voltage sampling value* an efficiency of the charging and discharging circuit / a grid voltage sampling value* a preset adjustment coefficient.

4. The control method of the charge and discharge circuit according to claim 1, characterized by, In the preset communication mode, a communication rate is 38400 bps.

5. A control device of a charge-discharge circuit, characterized by comprising: The control device is used for executing the control method of the charging and discharging circuit as claimed in any one of claims 1 to 4; the charging and discharging circuit comprises a direct current side controller and an alternating current side controller; the control device is applied to the direct current side controller, and the control device comprises the following modules: An obtaining module is configured to, when the charging and discharging circuit is in a discharging mode, obtain a direct current target value and a direct current sampling value of the charging and discharging circuit; A loop control module is configured to, according to the direct current target value, perform loop control on the direct current sampling value to obtain a grid-connected current given value; A sending module is configured to send the grid-connected current given value to the alternating current side controller through an emergency frame in a preset communication mode; the grid-connected current given value is used to instruct the alternating current side controller to control a grid-connected current sampling value according to the grid-connected current given value; In the preset communication mode, one emergency frame is inserted every N query frames, and a time interval for the direct current side controller to send two data frames is a charging and discharging mode switching requirement time length of the charging and discharging circuit / (N+1), N≥1.

6. The control device of the charge and discharge circuit according to claim 5, characterized by The loop control module is specifically configured to: A difference value between the direct current target value and the direct current sampling value is obtained; The difference value is input into a PI controller to obtain the grid-connected current given value.

7. A direct current side controller, characterized by, The computer program is stored in the memory and is invoked and run by the processor to execute the control method of the charge-discharge circuit according to any one of claims 1 to 4.

8. A charge-discharge circuit characterized by comprising: The DC side controller and the AC side controller communicate through a preset communication mode. The DC side controller and the AC side controller communicate through a preset communication mode.

9. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 8. The computer program is stored in the memory and is invoked and run by the processor to execute the control method of the charge-discharge circuit according to any one of claims 1 to 4.

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