Virtual impedance compensation control method and related device

Abstract

This application provides a virtual impedance compensation control method and related apparatus. The method includes: if a first bidirectional energy interaction module is determined to be the master, then multiple current values ​​of other bidirectional energy interaction modules are obtained through a communication module; the average current value of the multiple bidirectional energy interaction modules is determined; the average current value is sent to the other bidirectional energy interaction modules through the communication module; and a virtual impedance control strategy is executed based on the average current value. By introducing CAN bus communication and distinguishing between master and slave modules, the master obtains the current sampling value of the slave through the CAN bus, the master feeds back the average current value to the slave, and the bidirectional energy interaction modules execute the virtual impedance control strategy based on the average current value. This can suppress reactive circulating current and eliminate the problem of output voltage drop through distributed current balancing, which is beneficial to improving the stability of off-grid parallel systems.

Description

Technical Field

[0001] This application belongs to the field of bidirectional energy interaction technology, specifically relating to a virtual impedance compensation control method and related devices. Background Technology

[0002] V2G (Vehicle-to-Grid) refers to the bidirectional flow of energy between electric vehicles and the power grid via bidirectional charging and discharging devices. Electric vehicles can both draw power from the grid as loads and feed power back to the grid as distributed power sources. Off-grid V2G, on the other hand, involves multiple V2G-enabled electric vehicle charging stations disconnecting from the public grid to form an independent microgrid system. This system operates by coordinating and controlling power supply to local loads. In this mode, the system needs to autonomously establish voltage and frequency references and achieve power sharing among multiple modules.

[0003] The V2G module adopts a two-stage power conversion architecture: the front-end AC main circuit can be selected from a three-phase four-bridge topology, a three-phase three-bridge topology, or an active ANPC topology; the rear-end DC side uses a dual active bridge or a bidirectional full-bridge resonant circuit. The front-end AC side can freely achieve bidirectional energy flow control. When the V2G module operates in off-grid mode, the control algorithm based on the digital signal processor (DSP) executes Clark-Park coordinate transformation, converting the three-phase stationary coordinate system variables into two-phase rotating coordinate system DC variables. A voltage-frequency control strategy is adopted: the outer voltage loop maintains a stable AC output voltage amplitude, while the nested inductor current inner loop achieves rapid dynamic tracking, making the system equivalent to a controlled voltage source. In scenarios where multiple V2G modules are connected in parallel off-grid, this system constitutes a multi-voltage source parallel structure, resulting in reactive power circulating current issues. Summary of the Invention

[0004] This application provides a virtual impedance compensation control method and related apparatus. By introducing CAN bus communication and distinguishing between master and slave units among multiple bidirectional energy interaction modules, the master unit obtains the current sampling value of the slave unit through the CAN bus. The master unit feeds back the average current value to the slave unit. The bidirectional energy interaction module executes a virtual impedance control strategy based on the average current value, which can suppress reactive circulating current and eliminate the problem of output voltage drop through distributed current balancing, thereby improving the stability of off-grid parallel systems.

[0005] In a first aspect, embodiments of this application provide a virtual impedance compensation control method, the method comprising:

[0006] Determine whether the first bidirectional energy interaction module is the host;

[0007] If the first bidirectional energy interaction module is determined to be the host, then the communication module is used to obtain multiple current values ​​of the other bidirectional energy interaction modules besides the first bidirectional energy interaction module.

[0008] The average current value of the multiple bidirectional energy interaction modules is determined based on multiple current values ​​and the current value of the first bidirectional energy interaction module.

[0009] The average current value is sent to the other bidirectional energy interaction modules (excluding the first bidirectional energy interaction module) among the plurality of bidirectional energy interaction modules through the communication module;

[0010] Based on the average current, a virtual impedance control strategy is executed;

[0011] If it is determined that the first bidirectional energy interaction module is not the host, then the current value of the first bidirectional energy interaction module is sent to the host through the communication module.

[0012] In one possible example, the average current includes a first average current along the D-axis and a second average current along the Q-axis; the execution of a virtual impedance control strategy based on the average current includes:

[0013] Determine the virtual impedance coefficient, the first current component of the output current on the D-axis, the second current component on the Q-axis, the preset values, and the reference value of the rated voltage;

[0014] The first output voltage of the D-axis voltage loop is determined based on the first current component, the first average current, the virtual impedance coefficient, and the rated voltage reference value.

[0015] The second output voltage of the Q-axis voltage loop is determined based on the second current component, the second current average, the preset value, and the virtual impedance coefficient.

[0016] In one possible example, determining the first output voltage of the D-axis voltage loop based on the first current component, the first current mean, the virtual impedance coefficient, and the rated voltage reference value includes:

[0017] The difference between the first current mean and the first current component is determined to obtain the first current difference;

[0018] The first value is obtained by determining the product between the first current difference and the virtual impedance coefficient;

[0019] The difference between the rated voltage reference value and the first value is determined to obtain the second value;

[0020] The second value is used as the first output voltage of the D-axis voltage loop.

[0021] In one possible example, determining the second output voltage of the Q-axis voltage loop based on the second current component, the second current average, a preset value, and the virtual impedance coefficient includes:

[0022] The difference between the second current mean and the first current component is determined to obtain the second current difference;

[0023] The product between the second current difference and the virtual impedance coefficient is determined to obtain the third value;

[0024] The difference between the preset value and the third value is determined to obtain the fourth value;

[0025] The fourth value is used as the second output voltage of the Q-axis voltage loop.

[0026] In one possible example, after sending the current value of the first bidirectional energy interaction module to the host, the process includes:

[0027] Determine the target time period during which the first bidirectional energy interaction module does not receive a heartbeat message from the host;

[0028] If the target time period is determined to be longer than the preset time period, then the host is determined to be offline, and the first bidirectional energy interaction module is determined to be the new host.

[0029] In one possible example, after determining that the first bidirectional energy interaction module is the new host, the method further includes:

[0030] When a new second bidirectional energy interaction module is detected in the off-grid parallel system, the second bidirectional energy interaction module is determined to be a slave device.

[0031] In one possible example, before determining whether the first bidirectional energy interaction module is the host, the method further includes:

[0032] Determine the master-slave status of the multiple bidirectional energy interaction modules;

[0033] Obtain the power-on command from the monitoring platform;

[0034] Determine if there is an alarm in the first bidirectional energy interaction module;

[0035] If it is determined that there is an alarm in the first bidirectional energy interaction module, then an alarm message is sent to the monitoring platform;

[0036] Secondly, embodiments of this application provide a virtual impedance compensation control device applied to a first bidirectional energy interaction module in an off-grid parallel system. The off-grid parallel system includes multiple bidirectional energy interaction modules, a communication module, and a monitoring platform. The communication module connects the multiple bidirectional energy interaction modules and the monitoring platform. The first bidirectional energy interaction module is any one of the multiple bidirectional energy interaction modules. The virtual impedance compensation control device includes a judgment unit, an acquisition unit, a determination unit, a transmission unit, and a processing unit.

[0037] The judgment unit is used to determine whether the first bidirectional energy interaction module is a host;

[0038] The acquisition unit is used to acquire multiple current values ​​of other bidirectional energy interaction modules besides the first bidirectional energy interaction module through the communication module if it is determined that the first bidirectional energy interaction module is the host.

[0039] The determining unit is used to determine the average current value of the plurality of bidirectional energy interaction modules based on the plurality of current values ​​and the current value of the first bidirectional energy interaction module.

[0040] The transmission unit is used to send the average current value to the other bidirectional energy interaction modules among the plurality of bidirectional energy interaction modules, excluding the first bidirectional energy interaction module, through the communication module.

[0041] The processing unit is configured to execute a virtual impedance control strategy based on the average current value.

[0042] The transmission unit is further configured to, if it is determined that the first bidirectional energy interaction module is not the host, send the current value of the first bidirectional energy interaction module to the host through the communication module.

[0043] A third aspect of this application provides an electronic device including: a processor and a memory; and one or more programs stored in the memory and configured to be executed by the processor, the programs including instructions for some or all of the steps as described in the first aspect.

[0044] A fourth aspect of this application provides a computer-readable storage medium for storing a computer program that causes a computer to perform some or all of the steps described in the first aspect of this application.

[0045] A fifth aspect of this application provides a computer program product, comprising a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps described in the first aspect of this application. This computer program product may be a software installation package.

[0046] As can be seen from the embodiments of this application, the first bidirectional energy interaction module first determines whether it is a master. If it is determined to be a master, it obtains multiple current values ​​from the other bidirectional energy interaction modules (excluding the first one) through the communication module. Then, based on the multiple current values ​​and the current value of the first module, it determines the average current of the multiple bidirectional energy interaction modules. Furthermore, it sends the average current to the other bidirectional energy interaction modules (excluding the first one) through the communication module. Finally, it executes a virtual impedance control strategy based on the average current. If it is determined that the first module is not a master, it sends its current value to the master through the communication module. By introducing CAN bus communication and distinguishing between master and slave modules, the master obtains the current sampling value of the slave through the CAN bus, feeds back the average current to the slave, and the bidirectional energy interaction modules execute a virtual impedance control strategy based on the average current. This can suppress reactive circulating current and eliminate the output voltage drop problem through distributed current balancing, which is beneficial to improving the stability of the off-grid parallel system. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the architecture of an off-grid parallel equivalent model provided in an embodiment of this application;

[0049] Figure 2 This is a schematic diagram of the architecture of a virtual impedance compensation control system provided in an embodiment of this application;

[0050] Figure 3 This is a schematic diagram of the architecture of a bidirectional energy interaction module provided in an embodiment of this application;

[0051] Figure 4This is a flowchart illustrating a virtual impedance compensation control method provided in an embodiment of this application;

[0052] Figure 5 This is a schematic diagram of a process for implementing a virtual impedance control strategy provided in an embodiment of this application;

[0053] Figure 6 This is a schematic diagram of a master-slave switching process provided in an embodiment of this application;

[0054] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0055] Figure 8 This is a block diagram of the functional units of a virtual impedance compensation control device provided in an embodiment of this application. Detailed Implementation

[0056] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0057] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0058] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0059] In the embodiments of this application, "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone; A and B exist simultaneously; B exists alone. Among them, A and B can be singular or plural.

[0060] In this embodiment, the symbol " / " can indicate that the preceding and following objects are in an "or" relationship. Alternatively, the symbol " / " can also represent a division sign, i.e., performing a division operation. For example, A / B can mean A divided by B.

[0061] In the embodiments of this application, "at least one item" or its similar expression refers to any combination of these items, including any combination of a single item or a plurality of items. "One or more" means one or more, while "multiple" means two or more. For example, "at least one item" of a, b, or c can represent the following seven cases: a, b, c; a and b; a and c; b and c; a, b, and c. Each of a, b, and c can be an element or a set containing one or more elements.

[0062] In the embodiments of this application, "equal to" can be used with "greater than" and is applicable to technical solutions used when "greater than" is used; it can also be used with "less than" and is applicable to technical solutions used when "less than" is used. When "equal to" is used with "greater than", it is not used with "less than"; when "equal to" is used with "less than", it is not used with "greater than".

[0063] To better understand the solutions of the embodiments of this application, the electronic devices, related concepts and background that may be involved in the embodiments of this application will be introduced below.

[0064] The electronic device described in this application embodiment is a device with wireless communication capabilities, and may be referred to as a terminal, user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal device, vehicle-mounted terminal device, industrial control terminal device, UE unit, UE station, mobile station, remote station, remote terminal device, mobile device, UE terminal device, wireless communication device, UE agent, or UE device, etc. The terminal device can be fixed or mobile. It should be noted that the terminal device can support at least one wireless communication technology, such as LTE, New Radio (NR), Wideband Code Division Multiple Access (WCDMA), etc. For example, terminal devices can be mobile phones, tablets, desktop computers, laptops, all-in-one computers, in-vehicle terminals, virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, electronic devices or other processing devices connected to a wireless modem, wearable devices, terminal devices in future mobile communication networks, or terminal devices in future evolved public land mobile networks (PLMNs), etc.

[0065] like Figure 1 As shown, in the equivalent model of V2G off-grid parallel operation, it is assumed that the output potentials of the two V2G modules are respectively and Assuming that the output voltage phase and amplitude are theoretically controlled to be nearly identical, i.e. = However, the unequal line impedances of the two V2G modules will still cause a voltage deviation at the common coupling point PCC. ≠ This deviation will trigger reactive power circulating current. In actual parallel systems, the two V2G modules generate a continuous potential difference due to the DSP's sampling error, i.e. ≠ When the line impedance mismatch is superimposed, the circulating current may cause abnormal energy transfer between modules (for example, one V2G module transfers energy to another V2G module through a common coupling point), which may eventually lead to an overvoltage fault on the DC bus of the receiving module.

[0066] To address the aforementioned problems, this application provides a virtual impedance compensation control method and related apparatus.

[0067] Please see Figure 2 , Figure 2 This is a schematic diagram of the architecture of a virtual impedance compensation control system provided in an embodiment of this application. Figure 2 As shown, the virtual impedance compensation control system 1 includes multiple bidirectional energy interaction modules (first bidirectional energy interaction module, second bidirectional energy interaction module, ..., nth bidirectional energy interaction module), communication module 10 and monitoring platform 20. Communication module 10 is connected to multiple bidirectional energy interaction modules and monitoring platform 20 respectively.

[0068] The first bidirectional energy interaction module can be any one of multiple bidirectional energy interaction modules.

[0069] The communication module can be a CAN communication module.

[0070] Among them, the two-way energy interaction module is a V2G module, such as Figure 3 As shown, a single bidirectional energy interaction module includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first inductor L1, a second inductor L2, a third inductor L3, a first resistor R1, a second resistor R2, a third resistor R3, an inverter, a voltage loop, a current loop, a PWM module, and a multiplier. PCC represents the common coupling point, abc represents the three-phase stationary coordinate system, dq represents the two-phase rotating coordinate system, and abc / dq represents the conversion of three-phase AC quantities into two-phase DC quantities through Clark-Park transformation. IL_abc represents the three-phase inductor current sampling value, Uo_abc represents the three-phase voltage sampling value, Io_abc represents the three-phase output current sampling value, and the current value of the bidirectional energy interaction module.

[0071] The inverter is connected to the first capacitor C1. The inverter is connected to the first terminal of the first inductor L1, the first terminal of the second inductor L2, the first terminal of the third inductor L3, and the PWM module. The second terminal of the first inductor L1 is connected to the first terminal of the second capacitor C2 and the first terminal of the first resistor R1. The second terminal of the second inductor L2 is connected to the first terminal of the third capacitor C3 and the first terminal of the second resistor R2. The second terminal of the third inductor L3 is connected to the first terminal of the fourth capacitor C4 and the first terminal of the third resistor R3. The second terminal of the second capacitor is connected to the second terminal of the third capacitor and the second terminal of the fourth capacitor. The second terminal of the first resistor R1 is connected to the common coupling point. The second terminal of the second resistor R2 is connected to the common coupling point. The second terminal of the third resistor R3 is connected to the common coupling point. The multiplier is connected to the voltage loop and the current loop. The voltage loop and the current loop are connected to the PWM module. The communication module is used to send the first average current value avg_ld of the D-axis and the second average current value avg_lq of the Q-axis to the bidirectional energy interaction module.

[0072] Users can issue commands through the monitoring platform, including but not limited to module operating mode commands and power on / off commands.

[0073] In one possible example, the first bidirectional energy interaction module first determines whether it is the host. If it is determined to be the host, it obtains multiple current values ​​of the other bidirectional energy interaction modules (excluding the first one) through the communication module 10. Then, based on the multiple current values ​​and the current value of the first one, it determines the average current of the multiple bidirectional energy interaction modules. It then sends the average current to the other bidirectional energy interaction modules (excluding the first one) through the communication module 10. Based on the average current, it executes a virtual impedance control strategy. If it is determined that the first bidirectional energy interaction module is not the host, it sends the current value of the first one to the host through the communication module 10. By introducing CAN bus communication and distinguishing between master and slave units among multiple bidirectional energy interaction modules, the master unit obtains the current sampling value of the slave unit through the CAN bus, and feeds back the average current value to the slave unit. The bidirectional energy interaction module executes a virtual impedance control strategy based on the average current value, which can suppress reactive circulating current and eliminate the problem of output voltage drop through distributed current balancing, thus improving the stability of off-grid parallel systems.

[0074] Please see Figure 4 , Figure 4This is a flowchart illustrating a virtual impedance compensation control method provided in an embodiment of this application, applied to a first bidirectional energy interaction module in an off-grid parallel system. The off-grid parallel system includes multiple bidirectional energy interaction modules, a communication module, and a monitoring platform. The communication module connects the multiple bidirectional energy interaction modules and the monitoring platform respectively. The first bidirectional energy interaction module is any one of the multiple bidirectional energy interaction modules. The method includes:

[0075] Step S401: Determine whether the first bidirectional energy interaction module is the host.

[0076] Among them, communication can be achieved through a communication module, and the master-slave status of multiple bidirectional energy interaction modules can be defined.

[0077] Step S402: If it is determined that the first bidirectional energy interaction module is the host, then the communication module obtains multiple current values ​​of the other bidirectional energy interaction modules besides the first bidirectional energy interaction module.

[0078] The multiple current values ​​include multiple D-axis current values ​​and multiple Q-axis current values ​​of multiple bidirectional energy interaction modules. Each bidirectional energy interaction module has a corresponding D-axis current value and a Q-axis current value. The three-phase output current of a single bidirectional energy interaction module can be sampled and converted into two-phase DC current through Clark-Park transformation.

[0079] Step S403: Determine the average current value of the multiple bidirectional energy interaction modules based on the multiple current values ​​and the current value of the first bidirectional energy interaction module.

[0080] The average current includes the first average current along the D-axis and the second average current along the Q-axis.

[0081] Step S404: The average current value is sent to the other bidirectional energy interaction modules (excluding the first bidirectional energy interaction module) among the plurality of bidirectional energy interaction modules through the communication module.

[0082] Step S405: Execute a virtual impedance control strategy based on the average current value.

[0083] Among them, the virtual impedance control strategy establishes a dynamic voltage compensation mechanism through current feedback. By reducing the output voltage, it effectively increases the system output impedance, thereby suppressing the voltage deviation between parallel modules.

[0084] Each bidirectional energy interaction module, upon receiving the average current value, executes a virtual impedance control strategy based on that average current value.

[0085] Step S406: If it is determined that the first bidirectional energy interaction module is not the host, then the current value of the first bidirectional energy interaction module is sent to the host through the communication module.

[0086] The master unit can obtain the current value from the slave unit via the CAN bus (the frame ID contains the module number identifier) ​​every 10ms, determine the average current value, and broadcast it to the slave unit. The slave unit needs to report its current value via CAN communication every 1ms.

[0087] As can be seen from the embodiments of this application, the first bidirectional energy interaction module first determines whether it is a master. If it is determined to be a master, it obtains multiple current values ​​from the other bidirectional energy interaction modules (excluding the first one) through the communication module. Then, based on the multiple current values ​​and the current value of the first module, it determines the average current of the multiple bidirectional energy interaction modules. Furthermore, it sends the average current to the other bidirectional energy interaction modules (excluding the first one) through the communication module. Finally, it executes a virtual impedance control strategy based on the average current. If it is determined that the first module is not a master, it sends its current value to the master through the communication module. By introducing CAN bus communication and distinguishing between master and slave modules, the master obtains the current sampling value of the slave through the CAN bus, feeds back the average current to the slave, and the bidirectional energy interaction modules execute a virtual impedance control strategy based on the average current. This can suppress reactive circulating current and eliminate the output voltage drop problem through distributed current balancing, which is beneficial to improving the stability of the off-grid parallel system.

[0088] Please see Figure 5 In implementing the virtual impedance control strategy based on the average current, the above method may include the following steps:

[0089] Step S501: Determine the virtual impedance coefficient, the first current component of the output current of the first bidirectional energy interaction module on the D-axis, the second current component on the Q-axis, the preset value, and the rated voltage reference value.

[0090] Step S502: Determine the first output voltage of the D-axis voltage loop based on the first current component, the first average current, the virtual impedance coefficient, and the rated voltage reference value.

[0091] Step S503: Determine the second output voltage of the Q-axis voltage loop based on the second current component, the second average current, the preset value, and the virtual impedance coefficient.

[0092] The preset value can be set manually or by system default, and there is no restriction here. For example, the preset value is 0.

[0093] The rated voltage reference value can be set manually or by system default, and is not limited here. The rated voltage reference values ​​of different bidirectional energy interaction modules can be the same or different, and are not limited here.

[0094] As can be seen, in this embodiment, a dynamic voltage compensation mechanism is established through current feedback. By reducing the output voltage, the system output impedance is effectively increased, thereby suppressing the voltage deviation between parallel modules and improving the system stability.

[0095] In one possible example, regarding the determination of the first output voltage of the D-axis voltage loop based on the first current component, the first average current, the virtual impedance coefficient, and the rated voltage reference value, the above method may include the following steps: determining the difference between the first average current and the first current component to obtain a first current difference; determining the product between the first current difference and the virtual impedance coefficient to obtain a first value; determining the difference between the rated voltage reference value and the first value to obtain a second value; and using the second value as the first output voltage of the D-axis voltage loop.

[0096] The formula for the first output voltage is as follows:

[0097]

[0098] in, This is the first output voltage. This is the reference value for the rated voltage. This is the virtual impedance coefficient. The first average current, This is the first current component along the D-axis.

[0099] In this context, without introducing current averaging, as the load current increases, the voltage compensation term... The absolute value of increases accordingly, causing the voltage loop setpoint to... As the load continues to decrease, this positive feedback characteristic causes the AC output voltage to gradually drop as the load increases. This leads to two problems: firstly, the output voltage accuracy far exceeds the allowable range (deviating from the set value). Secondly, under extreme operating conditions, the AC undervoltage protection may be triggered, causing all modules to uncontrollably disconnect from the parallel system.

[0100] As can be seen, in this example, a dynamic voltage compensation mechanism is established through current feedback. By reducing the D-axis output voltage, the system output impedance is effectively increased, thereby suppressing voltage deviations between parallel modules and improving system stability.

[0101] In one possible example, regarding the determination of the second output voltage of the Q-axis voltage loop based on the second current component, the second average current, a preset value, and a virtual impedance coefficient, the above method may include the following steps: determining the difference between the second average current and the first current component to obtain a second current difference; determining the product between the second current difference and the virtual impedance coefficient to obtain a third value; determining the difference between the preset value and the third value to obtain a fourth value; and using the fourth value as the second output voltage of the Q-axis voltage loop.

[0102] The formula for the second output voltage is as follows:

[0103]

[0104] in, This is the second output voltage; 0 represents a preset value. This is the virtual impedance coefficient. The second average current. This is the second current component along the Q axis.

[0105] As can be seen, in this example, a dynamic voltage compensation mechanism is established through current feedback. By reducing the Q-axis output voltage, the system output impedance is effectively increased, thereby suppressing the voltage deviation between parallel modules and improving the system stability.

[0106] like Figure 6 As shown, after sending the current value of the first bidirectional energy interaction module to the host, the above method may include the following steps:

[0107] Step S601: Determine the target time period during which the first bidirectional energy interaction module does not receive a heartbeat message from the host;

[0108] Step S602: If it is determined that the target time period is longer than the preset time period, then the host is determined to be offline, and the first bidirectional energy interaction module is determined to be the new host.

[0109] The preset time period can be set manually or by system default, and there is no limitation here. For example, the preset time period is 20ms.

[0110] Among them, a master-slave switching mechanism can be designed. If the slave does not collect the heartbeat message from the master, the timer will start to accumulate. When the slave does not receive the heartbeat message from the master within 20ms, it is determined that the master is offline. The master may have interrupted CAN communication, been removed from the parallel system, or experienced a failure. The master-slave role switching is automatically triggered, that is, the original master is downgraded to a slave and a new master is selected from the preset priorities.

[0111] As can be seen, in this example, the master-slave switching mechanism is designed to avoid the inability to properly compensate for virtual impedance when the master goes offline, which helps to improve the stability of the system.

[0112] In one possible example, after determining that the first bidirectional energy interaction module is a new host, the above method may further include the following step: when a second bidirectional energy interaction module is detected to be newly connected in the off-grid parallel system, the second bidirectional energy interaction module is determined to be a slave.

[0113] Among them, the bidirectional energy interaction module supports hot-swapping. When a new module is reconnected to the parallel system, it can be classified as a slave and added to the group that supplies current.

[0114] When a bidirectional energy interaction module is detected to have been removed from the parallel system, the host promptly updates the average current.

[0115] As can be seen from this example, designing the handling methods for adding and removing new modules in a parallel system is beneficial to improving the stability of the system.

[0116] In one possible example, before determining whether the first bidirectional energy interaction module is a host, the above method may further include the following steps: classifying the master and slave states of the plurality of bidirectional energy interaction modules; obtaining a power-on command from the monitoring platform; determining whether the first bidirectional energy interaction module has an alarm; if it is determined that the first bidirectional energy interaction module has an alarm, sending alarm information to the monitoring platform; if it is determined that the first bidirectional energy interaction module does not have an alarm, performing a soft start power-on.

[0117] The master-slave status of multiple bidirectional energy interaction modules can be determined by CAN communication based on preset priorities. These preset priorities can be determined by factors such as serial number, hardware performance, parameters, and operating status; no specific limitations are specified here.

[0118] The V2G module operates in off-grid mode. When the DC side is powered on, all variables such as power-on / off commands and loop parameters are initialized. The operation of the V2G module in off-grid mode depends on the command issued by the user through the monitoring platform. The monitoring platform issues a power-on command to the module, and the module will perform a series of soft-start operations.

[0119] The V2G module's DSP detects alarms. If an alarm is detected, the alarm information is sent to the monitoring platform. If no alarm is detected, the next step of soft-start is performed. Each module successfully starts up after a soft-start without any alarms.

[0120] As can be seen, in this example, by dividing the master and slave states and performing alarm detection on the bidirectional energy interaction module, the normal soft start of the bidirectional energy interaction module is ensured, which helps to improve the stability of the system.

[0121] Please see Figure 7 , Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application, applied to a first bidirectional energy interaction module in an off-grid parallel system. The off-grid parallel system includes multiple bidirectional energy interaction modules, a communication module, and a monitoring platform. The communication module is connected to the multiple bidirectional energy interaction modules and the monitoring platform respectively. The first bidirectional energy interaction module is any one of the multiple bidirectional energy interaction modules. Figure 7 As shown, the electronic device includes a processor, a memory, a communication interface, and one or more programs, wherein the one or more programs are stored in the memory, and the one or more programs are configured to be executed by the processor according to the following instructions:

[0122] Determine whether the first bidirectional energy interaction module is the host;

[0123] If the first bidirectional energy interaction module is determined to be the host, then the communication module is used to obtain multiple current values ​​of the other bidirectional energy interaction modules besides the first bidirectional energy interaction module.

[0124] The average current value of the multiple bidirectional energy interaction modules is determined based on multiple current values ​​and the current value of the first bidirectional energy interaction module.

[0125] The average current value is sent to the other bidirectional energy interaction modules (excluding the first bidirectional energy interaction module) among the plurality of bidirectional energy interaction modules through the communication module;

[0126] Based on the average current, a virtual impedance control strategy is executed;

[0127] If it is determined that the first bidirectional energy interaction module is not the host, then the current value of the first bidirectional energy interaction module is sent to the host through the communication module.

[0128] As can be seen, in this embodiment, the electronic device first determines whether the first bidirectional energy interaction module is the master. If the first bidirectional energy interaction module is determined to be the master, it obtains multiple current values ​​of the other bidirectional energy interaction modules (excluding the first one) through the communication module. Then, based on the multiple current values ​​and the current value of the first bidirectional energy interaction module, it determines the average current of the multiple bidirectional energy interaction modules. Furthermore, it sends the average current to the other bidirectional energy interaction modules (excluding the first one) through the communication module. Finally, it executes a virtual impedance control strategy based on the average current. If the first bidirectional energy interaction module is determined not to be the master, it sends its current value to the master through the communication module. By introducing CAN bus communication and distinguishing between master and slave modules, the master obtains the current sampling value of the slave module through the CAN bus, and the master feeds back the average current to the slave. The bidirectional energy interaction modules execute a virtual impedance control strategy based on the average current, which can suppress reactive circulating current and eliminate the output voltage drop problem through distributed current balancing, thus improving the stability of the off-grid parallel system.

[0129] In one possible example, the average current includes a first average current along the D-axis and a second average current along the Q-axis; regarding the execution of the virtual impedance control strategy based on the average current, the above procedure includes instructions for performing the following steps:

[0130] Determine the virtual impedance coefficient, the first current component of the output current on the D-axis, the second current component on the Q-axis, the preset values, and the reference value of the rated voltage;

[0131] The first output voltage of the D-axis voltage loop is determined based on the first current component, the first average current, the virtual impedance coefficient, and the rated voltage reference value.

[0132] The second output voltage of the Q-axis voltage loop is determined based on the second current component, the second current average, the preset value, and the virtual impedance coefficient.

[0133] In one possible example, regarding the determination of the first output voltage of the D-axis voltage loop based on the first current component, the first current mean, the virtual impedance coefficient, and the rated voltage reference value, the above procedure includes instructions for performing the following steps:

[0134] The difference between the first current mean and the first current component is determined to obtain the first current difference;

[0135] The first value is obtained by determining the product between the first current difference and the virtual impedance coefficient;

[0136] The difference between the rated voltage reference value and the first value is determined to obtain the second value;

[0137] The second value is used as the first output voltage of the D-axis voltage loop.

[0138] In one possible example, regarding the determination of the second output voltage of the Q-axis voltage loop based on the second current component, the second current mean, a preset value, and a virtual impedance coefficient, the above procedure includes instructions for performing the following steps:

[0139] The difference between the second current mean and the first current component is determined to obtain the second current difference;

[0140] The product between the second current difference and the virtual impedance coefficient is determined to obtain the third value;

[0141] The difference between the preset value and the third value is determined to obtain the fourth value;

[0142] The fourth value is used as the second output voltage of the Q-axis voltage loop.

[0143] In one possible example, after sending the current value of the first bidirectional energy interaction module to the host, the above procedure further includes instructions for performing the following steps:

[0144] Determine the target time period during which the first bidirectional energy interaction module does not receive a heartbeat message from the host;

[0145] If the target time period is determined to be longer than the preset time period, then the host is determined to be offline, and the first bidirectional energy interaction module is determined to be the new host.

[0146] In one possible example, after determining that the first bidirectional energy interaction module is the new host, the above procedure further includes instructions for performing the following steps:

[0147] When a new second bidirectional energy interaction module is detected in the off-grid parallel system, the second bidirectional energy interaction module is determined to be a slave device.

[0148] In one possible example, before determining whether the first bidirectional energy interaction module is the host, the above program also includes instructions for performing the following steps:

[0149] Determine the master-slave status of the multiple bidirectional energy interaction modules;

[0150] Obtain the power-on command from the monitoring platform;

[0151] Determine if there is an alarm in the first bidirectional energy interaction module;

[0152] If it is determined that there is an alarm in the first bidirectional energy interaction module, then an alarm message is sent to the monitoring platform;

[0153] If it is determined that there is no alarm in the first bidirectional energy interaction module, then a soft start is performed.

[0154] The above primarily describes the solutions of the embodiments of this application from the perspective of the method execution process. It is understood that, in order to achieve the above functions, the electronic device includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments provided herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware 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 implementation should not be considered beyond the scope of this application.

[0155] This application embodiment can divide the electronic device into functional units according to the above method example. For example, each function can be divided into a separate functional unit, or two or more functions can be integrated into one processing unit. The integrated unit can be implemented in hardware or as a software functional unit. It should be noted that the unit division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0156] When dividing each function into modules according to its corresponding function. Figure 8 A functional unit block diagram of a virtual impedance compensation control device is given, such as... Figure 8 As shown, a first bidirectional energy interaction module is applied in an off-grid parallel system. The off-grid parallel system includes multiple bidirectional energy interaction modules, a communication module, and a monitoring platform. The communication module connects the multiple bidirectional energy interaction modules and the monitoring platform. The first bidirectional energy interaction module is any one of the multiple bidirectional energy interaction modules. The device includes a judgment unit 801, an acquisition unit 802, a determination unit 803, a transmission unit 804, and a processing unit 805.

[0157] The judgment unit 801 is used to determine whether the first bidirectional energy interaction module is a host;

[0158] The acquisition unit 802 is used to acquire multiple current values ​​of other bidirectional energy interaction modules besides the first bidirectional energy interaction module through the communication module if it is determined that the first bidirectional energy interaction module is the host.

[0159] The determining unit 803 is used to determine the average current value of the plurality of bidirectional energy interaction modules based on the plurality of current values ​​and the current value of the first bidirectional energy interaction module.

[0160] The transmission unit 804 is used to send the average current value to the other bidirectional energy interaction modules among the plurality of bidirectional energy interaction modules, excluding the first bidirectional energy interaction module, through the communication module.

[0161] The processing unit 805 is used to execute a virtual impedance control strategy based on the average current value.

[0162] The transmission unit 804 is further configured to send the current value of the first bidirectional energy interaction module to the host through the communication module if it is determined that the first bidirectional energy interaction module is not the host.

[0163] As can be seen from the embodiments of this application, the virtual impedance compensation control device first determines whether the first bidirectional energy interaction module is the master. If the first bidirectional energy interaction module is determined to be the master, it obtains multiple current values ​​from the other bidirectional energy interaction modules (excluding the first one) through the communication module. Then, based on the multiple current values ​​and the current value of the first bidirectional energy interaction module, it determines the average current value of the multiple bidirectional energy interaction modules. Furthermore, it sends the average current value to the other bidirectional energy interaction modules (excluding the first one) through the communication module. Finally, it executes a virtual impedance control strategy based on the average current value. If the first bidirectional energy interaction module is determined not to be the master, it sends the current value of the first bidirectional energy interaction module to the master through the communication module. By introducing CAN bus communication and distinguishing between master and slave devices among the multiple bidirectional energy interaction modules, the master obtains the current sampling value of the slave device through the CAN bus, and the master feeds back the average current value to the slave device. The bidirectional energy interaction modules execute a virtual impedance control strategy based on the average current value, which can suppress reactive circulating current and eliminate the problem of output voltage drop through distributed current balancing, thus improving the stability of the off-grid parallel system.

[0164] In one possible example, the average current includes a first average current along the D-axis and a second average current along the Q-axis; in terms of executing the virtual impedance control strategy based on the average current, the determining unit 803 is specifically configured to:

[0165] Determine the virtual impedance coefficient, the first current component of the output current on the D-axis, the second current component on the Q-axis, the preset values, and the reference value of the rated voltage;

[0166] The first output voltage of the D-axis voltage loop is determined based on the first current component, the first average current, the virtual impedance coefficient, and the rated voltage reference value.

[0167] The second output voltage of the Q-axis voltage loop is determined based on the second current component, the second current average, the preset value, and the virtual impedance coefficient.

[0168] In one possible example, regarding the determination of the first output voltage of the D-axis voltage loop based on the first current component, the first current mean, the virtual impedance coefficient, and the rated voltage reference value, the determining unit 803 is specifically used for:

[0169] The difference between the first current mean and the first current component is determined to obtain the first current difference;

[0170] The first value is obtained by determining the product between the first current difference and the virtual impedance coefficient;

[0171] The difference between the rated voltage reference value and the first value is determined to obtain the second value;

[0172] The second value is used as the first output voltage of the D-axis voltage loop.

[0173] In one possible example, regarding the determination of the second output voltage of the Q-axis voltage loop based on the second current component, the second current mean, a preset value, and the virtual impedance coefficient, the determining unit 803 is specifically used for:

[0174] The difference between the second current mean and the first current component is determined to obtain the second current difference;

[0175] The product between the second current difference and the virtual impedance coefficient is determined to obtain the third value;

[0176] The difference between the preset value and the third value is determined to obtain the fourth value;

[0177] The fourth value is used as the second output voltage of the Q-axis voltage loop.

[0178] In one possible example, after sending the current value of the first bidirectional energy interaction module to the host, the determining unit 803 is further specifically used for:

[0179] Determine the target time period during which the first bidirectional energy interaction module does not receive a heartbeat message from the host;

[0180] If the target time period is determined to be longer than the preset time period, then the host is determined to be offline, and the first bidirectional energy interaction module is determined to be the new host.

[0181] In one possible example, after determining that the first bidirectional energy interaction module is the new host, the determining unit 803 is further specifically used for:

[0182] When a new second bidirectional energy interaction module is detected in the off-grid parallel system, the second bidirectional energy interaction module is determined to be a slave device.

[0183] In one possible example, before determining whether the first bidirectional energy interaction module is the host, the processing unit 805 is further specifically used for:

[0184] Determine the master-slave status of the multiple bidirectional energy interaction modules;

[0185] Obtain the power-on command from the monitoring platform;

[0186] Determine if there is an alarm in the first bidirectional energy interaction module;

[0187] If it is determined that there is an alarm in the first bidirectional energy interaction module, then an alarm message is sent to the monitoring platform;

[0188] If it is determined that there is no alarm in the first bidirectional energy interaction module, then a soft start is performed.

[0189] It should be noted that all relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0190] The electronic device provided in this embodiment is used to execute the above-described virtual impedance compensation control method, and therefore can achieve the same effect as the above-described implementation method.

[0191] When using integrated units, the electronic device may include a processing module, a storage module, and a communication module. The processing module can be used to control and manage the actions of the electronic device; for example, it can support the electronic device in executing the steps performed by the aforementioned functional units. The storage module can support the electronic device in executing stored program code and data. The communication module can support communication between the electronic device and other devices.

[0192] The processing module can be a processor or a controller. It can implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module can be a memory. The communication module can specifically be a radio frequency circuit, a Bluetooth chip, a Wi-Fi chip, or other devices that interact with other electronic devices.

[0193] This application also provides a computer storage medium storing a computer program for electronic data interchange, which causes a computer to perform some or all of the steps of any of the methods described in the above method embodiments, wherein the computer includes an electronic device.

[0194] This application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of any of the methods described in the above method embodiments. The computer program product may be a software installation package, and the computer includes a control platform.

[0195] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0196] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0197] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above 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 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 or other forms.

[0198] The units described above 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.

[0199] Furthermore, the functional units in the various embodiments of this application 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.

[0200] If the aforementioned integrated units are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0201] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage device, which may include: a flash drive, a read-only memory, a random access memory, a magnetic disk, or an optical disk, etc.

[0202] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A virtual impedance compensation control method, characterized in that, A first bidirectional energy interaction module is applied in an off-grid parallel system, the off-grid parallel system including multiple bidirectional energy interaction modules, a communication module, and a monitoring platform, the communication module connecting the multiple bidirectional energy interaction modules and the monitoring platform respectively, and the first bidirectional energy interaction module being any one of the multiple bidirectional energy interaction modules; the method includes: Determine whether the first bidirectional energy interaction module is the host; If the first bidirectional energy interaction module is determined to be the host, then the communication module is used to obtain multiple current values ​​of the other bidirectional energy interaction modules besides the first bidirectional energy interaction module. The average current value of the multiple bidirectional energy interaction modules is determined based on multiple current values ​​and the current value of the first bidirectional energy interaction module. The average current value is sent to the other bidirectional energy interaction modules (excluding the first bidirectional energy interaction module) among the plurality of bidirectional energy interaction modules through the communication module; Based on the average current, a virtual impedance control strategy is executed; If it is determined that the first bidirectional energy interaction module is not the host, then the current value of the first bidirectional energy interaction module is sent to the host through the communication module.

2. The method according to claim 1, characterized in that, The average current includes a first average current along the D-axis and a second average current along the Q-axis; the execution of a virtual impedance control strategy based on the average current includes: Determine the virtual impedance coefficient, the first current component of the output current on the D-axis, the second current component on the Q-axis, the preset values, and the reference value of the rated voltage; The first output voltage of the D-axis voltage loop is determined based on the first current component, the first average current, the virtual impedance coefficient, and the rated voltage reference value. The second output voltage of the Q-axis voltage loop is determined based on the second current component, the second current average, the preset value, and the virtual impedance coefficient.

3. The method according to claim 2, characterized in that, The step of determining the first output voltage of the D-axis voltage loop based on the first current component, the first average current, the virtual impedance coefficient, and the rated voltage reference value includes: The difference between the first current mean and the first current component is determined to obtain the first current difference; The first value is obtained by determining the product between the first current difference and the virtual impedance coefficient; The difference between the rated voltage reference value and the first value is determined to obtain the second value; The second value is used as the first output voltage of the D-axis voltage loop.

4. The method according to claim 2, characterized in that, The step of determining the second output voltage of the Q-axis voltage loop based on the second current component, the second current average, a preset value, and the virtual impedance coefficient includes: The difference between the second current mean and the second current component is determined to obtain the second current difference; The product between the second current difference and the virtual impedance coefficient is determined to obtain the third value; The difference between the preset value and the third value is determined to obtain the fourth value; The fourth value is used as the second output voltage of the Q-axis voltage loop.

5. The method according to claim 1, characterized in that, After sending the current value of the first bidirectional energy interaction module to the host, the process includes: Determine the target time period during which the first bidirectional energy interaction module does not receive a heartbeat message from the host; If the target time period is determined to be longer than the preset time period, then the host is determined to be offline, and the first bidirectional energy interaction module is determined to be the new host.

6. The method according to claim 5, characterized in that, After determining that the first bidirectional energy interaction module is the new host, the method further includes: When a new second bidirectional energy interaction module is detected in the off-grid parallel system, the second bidirectional energy interaction module is determined to be a slave device.

7. The method according to claim 1, characterized in that, Before determining whether the first bidirectional energy interaction module is the host, the method further includes: Determine the master-slave status of the multiple bidirectional energy interaction modules; Obtain the power-on command from the monitoring platform; Determine if there is an alarm in the first bidirectional energy interaction module; If it is determined that there is an alarm in the first bidirectional energy interaction module, then an alarm message is sent to the monitoring platform; If it is determined that there is no alarm in the first bidirectional energy interaction module, then a soft start is performed.

8. A virtual impedance compensation control device, characterized in that, A first bidirectional energy interaction module is applied in an off-grid parallel system. The off-grid parallel system includes multiple bidirectional energy interaction modules, a communication module, and a monitoring platform. The communication module connects the multiple bidirectional energy interaction modules and the monitoring platform. The first bidirectional energy interaction module is any one of the multiple bidirectional energy interaction modules. The virtual impedance compensation control device includes a judgment unit, an acquisition unit, a determination unit, a transmission unit, and a processing unit. The judgment unit is used to determine whether the first bidirectional energy interaction module is a host; The acquisition unit is used to acquire multiple current values ​​of the other bidirectional energy interaction modules besides the first bidirectional energy interaction module through the communication module if it is determined that the first bidirectional energy interaction module is the host. The determining unit is used to determine the average current value of the plurality of bidirectional energy interaction modules based on the plurality of current values ​​and the current value of the first bidirectional energy interaction module. The transmission unit is used to send the average current value to the other bidirectional energy interaction modules among the plurality of bidirectional energy interaction modules, excluding the first bidirectional energy interaction module, through the communication module. The processing unit is configured to execute a virtual impedance control strategy based on the average current value. The transmission unit is further configured to, if it is determined that the first bidirectional energy interaction module is not the host, send the current value of the first bidirectional energy interaction module to the host through the communication module.

9. An electronic device, characterized in that, It includes a processor and a memory, the memory being used to store one or more programs and configured to be executed by the processor, the programs including instructions for performing the steps of the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, A computer program for storing electronic data interchange, wherein the computer program causes a computer to perform the method as described in any one of claims 1-7.

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