Building block type parallel coordination control method and system for modular converter

Abstract

The invention discloses a modular converter building block type parallel coordination control method and system, and the method comprises the steps: enabling different AC / DC modules to be connected in parallel through a parallel module, and enabling the different AC / DC modules to employ different IDs to carry out the identification of the operation data, which is actively and periodically uploaded by the AC / DC modules; a rapid communication mode is established between the plurality of AC / DC modules connected in parallel and the coordination controller, and the maximum number of AC / DC module ID numbers are preset by the coordination controller; when the coordination controller receives communication data corresponding to a certain ID, the online state of an AC / DC module of the ID is judged; when the AC / DC modules are in an on-line state, the coordination controller analyzes the received operation data of the on-line AC / DC modules, obtains the fault code of each module, and counts the AC / DC modules of which the fault codes are not zero to obtain the number of non-fault modules; and the coordination controller sends a control message to the AC / DC module which is on line and is not faulty, and performs periodic control on the AC / DC module. According to the AC / DC module, plug-and-play parallel connection can be achieved, and reliability and UDC direct current voltage stabilization and VF alternating current voltage stabilization performance are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics and flexible distribution networks, and in particular to a modular converter building block parallel coordinated control method and system. Background Art

[0002] As an important means of grid-connected power generation and flexible control of power grids, power electronics technology has developed rapidly. In recent years, with the access of massive distributed power sources and new loads such as charging piles, the application of high-power converters has increased significantly. Typical application scenarios include distributed energy storage, flexible interconnection and power quality management.

[0003] The high-power centralized converter solution has a high degree of customization and is not easy to expand in capacity; the switching frequency is low and the noise is high; the technical threshold is high and the production and debugging efficiency is low. The modular solution can make up for these shortcomings; however, due to the large number of parallel modules, it will also face new problems such as AC side resonance, no-load circulating current, and load current sharing. In addition, the overall external performance of the modular converter solution is slightly worse than that of the centralized one, especially the VF AC voltage regulation performance is its shortcoming. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a modular converter building block parallel coordinated control method and system to solve the problem that the existing modular solutions cannot achieve flexible configuration of converter capacity and improve equipment carrying capacity and reliability.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides a modular converter building block parallel coordinated control method, comprising: the AC ports of all parallel modules of the modular converter are connected to the AC busbar, and the DC ports are connected to the DC busbar; the AC busbar is connected to the AC circuit breaker, the DC busbar is connected to the DC fault protection unit, and the DC fault protection unit is connected to the DC circuit breaker, and the method comprises:

[0009] The parallel connection module connects different AC / DC modules in parallel, and the different AC / DC modules use different IDs to identify the operation data actively periodically sent by the AC / DC modules;

[0010] The multiple parallel AC / DC modules establish a fast communication mode with the coordination controller, and the coordination controller presets a maximum number of AC / DC module ID numbers; when the coordination controller receives communication data corresponding to a certain ID, it determines the online status of the AC / DC module of the ID;

[0011] When the AC / DC module is in an online state, the coordination controller parses the received operation data of the online AC / DC module and obtains the fault code of each module, counts the AC / DC modules whose fault codes are not zero, and obtains the number of non-faulty modules;

[0012] The coordination controller sends a control message to an online and non-faulty AC / DC module to perform periodic control on the AC / DC module.

[0013] As a preferred solution of the modular inverter building block parallel coordinated control method described in the present invention, when the coordinated controller receives communication data corresponding to a certain ID, judging the online status of the AC / DC module of the ID also includes: if the coordinated controller fails to receive the communication data of the ID within a continuous setting time, the AC / DC module of the ID is in an offline state.

[0014] As a preferred solution of the modular converter building block parallel coordinated control method of the present invention, wherein: the control message sent by the coordinated controller to the AC / DC module that is online and not faulty includes at least the working mode, start / stop, reset, power command, and voltage command;

[0015] The AC / DC modular converter has the following operating modes: PQ constant power operating mode, UDC DC voltage stabilization operating mode, and VF AC voltage stabilization operating mode.

[0016] As a preferred solution of the modular converter building block parallel coordinated control method of the present invention, wherein: the AC / DC modular converter whole machine operates in the PQ constant power working mode, including: setting each AC / DC module to work in the PQ constant power working mode, and the coordination controller evenly distributes power to the online and non-faulty AC / DC modules according to the active power instruction and reactive power instruction of the host computer;

[0017] When any AC / DC module is offline, the AC / DC module automatically detects the loss of the coordination controller control message and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module;

[0018] When any AC / DC module fails, the AC / DC module will automatically shut down, the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will reallocate the power instructions to the online and non-faulty AC / DC modules.

[0019] As a preferred solution of the modular converter building block parallel coordinated control method of the present invention, wherein: the AC / DC modular converter whole machine operates in the UDC DC voltage stabilization working mode includes: adopting the UDC drooping mode in parallel, the master-slave working mode, setting the master AC / DC module to work in the UDC DC voltage stabilization working mode, setting the slave AC / DC module to work in the UDC drooping working mode;

[0020] The total active power of the AC / DC modular converter is determined by the load or distributed power source connected to the DC side. The coordination controller counts the total active power sent by all online modules and evenly distributes it to the online and non-faulty AC / DC modules according to the reactive power instruction of the host computer.

[0021] When any slave AC / DC module goes offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller reallocates the power instructions to the online and non-faulty AC / DC modules.

[0022] When any slave AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will redistribute the power command to the online and non-faulty AC / DC modules;

[0023] When any main AC / DC module is offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the UDC voltage regulation working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module;

[0024] When any main AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the UDC voltage regulation working mode, and the coordination controller redistributes the power instructions to the online and non-faulty AC / DC modules.

[0025] As a preferred solution of the modular converter building block parallel coordinated control method of the present invention, wherein: the AC / DC modular converter whole machine operates in the VF AC voltage stabilization working mode including:

[0026] Adopt VF droop mode parallel connection, master-slave working mode, set the master AC / DC module to work in VF AC voltage regulation working mode, set the slave AC / DC module to work in VF droop working mode; before starting operation, the coordination controller actively sends phase synchronization signals to each AC / DC module;

[0027] The total active power and total reactive power of the AC / DC modular converter are determined by the load or distributed power source connected to the AC side. The coordination controller counts the total active power and total reactive power sent by all online modules and evenly distributes them to the online and non-faulty AC / DC modules.

[0028] As a preferred solution of the modular converter building block parallel coordinated control method of the present invention, it also includes:

[0029] When any slave AC / DC module goes offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller reallocates the power instructions to the online and non-faulty AC / DC modules.

[0030] When any slave AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will reallocate power commands to online and non-faulty AC / DC modules.

[0031] When any main AC / DC module is offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the VF AC voltage stabilization working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module;

[0032] When any main AC / DC module fails, the AC / DC module will automatically shut down. The number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the VF AC voltage regulation working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module.

[0033] In a second aspect, the present invention provides a modular converter building block parallel coordinated control system, wherein the AC ports of all parallel modules of the modular converter are connected to the AC busbar, and the DC ports are connected to the DC busbar; the AC busbar is connected to the AC circuit breaker, the DC busbar is connected to the DC fault protection unit, and the DC fault protection unit is connected to the DC circuit breaker, and the system comprises:

[0034] A data identification module, used for the parallel connection module to connect different AC / DC modules in parallel, and the different AC / DC modules use different IDs to identify the operation data actively periodically sent by the AC / DC modules;

[0035] A judgment module is used for establishing a fast communication mode between the plurality of parallel AC / DC modules and the coordination controller, wherein the coordination controller presets a maximum number of AC / DC module ID numbers; when the coordination controller receives communication data corresponding to a certain ID, it judges the online status of the AC / DC module of the ID;

[0036] A fault statistics module, used for, when the AC / DC module is in an online state, the coordination controller to parse the received operation data of the online AC / DC module and obtain the fault code of each module, count the AC / DC modules whose fault codes are not zero, and obtain the number of non-faulty modules;

[0037] The coordination control module is used for the coordination controller to send control messages to the AC / DC modules that are online and not at fault, and to perform periodic control on the AC / DC modules.

[0038] In a third aspect, the present invention provides a computing device, comprising:

[0039] Memory and processor;

[0040] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the modular converter building block parallel coordinated control method are implemented.

[0041] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the modular converter building block parallel coordinated control method.

[0042] Compared with the prior art, the present invention has the following beneficial effects: when designing the AC / DC module circuit, the present invention suppresses high-frequency ripple and avoids high-frequency resonance through the LCL filter, suppresses high-frequency circulating current between modules through the common-mode filter, and suppresses low-frequency circulating current between modules through the current inner loop control strategy, which provides the hardware basic conditions for plug-and-play building block parallel connection. The AC / DC module actively and periodically uploads the operating data and identifies it with different ID numbers; the coordination controller automatically identifies the online AC / DC modules, counts the number of non-faulty modules, performs periodic control on the online and non-faulty AC / DC modules, and actively removes offline or faulty modules, which provides a flexible communication and control mechanism for plug-and-play building block parallel connection. In the UDC DC voltage regulation and VF AC voltage regulation working modes, the droop mode is adopted in parallel, and each module has the voltage source characteristics, and the carrying capacity and reliability of the whole machine are significantly enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0044] Figure 1 An electrical schematic diagram of a main circuit of a modular converter according to a modular converter building block parallel coordinated control method and system according to an embodiment of the present invention;

[0045] Figure 2 A block diagram of the AC / DC module current inner loop control of a modular converter building block parallel coordinated control method and system according to an embodiment of the present invention;

[0046] Figure 3 A wiring diagram of a whole machine coordination controller of a modular converter building block parallel coordination control method and system according to an embodiment of the present invention;

[0047] Figure 4 A schematic diagram of the communication and control mechanism between the whole machine coordination controller and the AC / DC module of a modular converter building block parallel coordination control method and system according to an embodiment of the present invention;

[0048] Figure 5 A schematic diagram of a method for parallel control of AC / DC modules in a typical working mode of a modular converter building block parallel coordinated control method and system according to an embodiment of the present invention;

[0049] Figure 6A schematic diagram of an experimental scheme of a PQ constant power and UDC DC voltage stabilization working mode of a modular converter building block parallel coordinated control method and system according to an embodiment of the present invention;

[0050] Figure 7 A schematic diagram of an experimental scheme of a whole machine VF AC voltage stabilization working mode of a modular converter building block parallel coordinated control method and system according to an embodiment of the present invention;

[0051] Figure 8 This is an AC voltage waveform diagram when the whole machine VF AC voltage stabilization working mode of a modular converter building block parallel coordinated control method and system described in one embodiment of the present invention is started. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0053] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0054] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0055] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0056] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0057] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Example 1

[0059] Reference Figure 1 to Figure 5 , is an embodiment of the present invention, which provides a modular converter building block parallel coordinated control method, including: the AC ports of all parallel modules of the modular converter are connected to the AC busbar, and the DC ports are connected to the DC busbar; the AC busbar is connected to the AC circuit breaker, the DC busbar is connected to the DC fault protection unit, and the DC fault protection unit is connected to the DC circuit breaker. The method includes:

[0060] The parallel module connects different AC / DC modules in parallel, and different AC / DC modules use different IDs to identify the operation data actively periodically sent by the AC / DC modules;

[0061] Multiple parallel AC / DC modules establish a fast communication mode with the coordination controller, and the coordination controller presets the maximum number of AC / DC module ID numbers; when the coordination controller receives communication data corresponding to a certain ID, it determines the online status of the AC / DC module of the ID;

[0062] When the AC / DC module is in an online state, the coordination controller parses the received operation data of the online AC / DC module and obtains the fault code of each module, counts the AC / DC modules with fault codes not zero, and obtains the number of non-faulty modules;

[0063] The coordination controller sends control messages to the AC / DC modules that are online and not at fault, and performs periodic control on the AC / DC modules.

[0064] It should be noted that the coordination controller can preset a maximum number of AC / DC module ID numbers according to the communication requirements with the AC / DC modules. When the AC / DC modules are connected to the CAN bus, the ID numbers of the various AC / DC modules cannot be the same.

[0065] In an optional embodiment, when the AC / DC module communicates with the coordination controller, the coordination controller may set the maximum number of supported modules to 8, and the corresponding number of AC / DC module ID numbers is 8, and the ID range may be 0-7.

[0066] It should also be noted that the AC side of the AC / DC module in the embodiment of the present application includes an LCL filter and a common mode filter; when designing the AC / DC module circuit, the crossover frequency of the LCL filter on the AC side of the AC / DC module is less than the switching frequency, suppressing high-frequency ripple currents above the switching frequency to avoid AC parallel resonance, which is expressed as:

[0067]

[0068] Among them, f c is the LCL filter crossover frequency, L1, L2, C f are the LCL filter parameters, f sw is the switching frequency of the three-phase full-bridge of the AC / DC module.

[0069] The common mode filter on the AC side of the AC / DC module has a power frequency impedance much greater than the AC side line impedance, which suppresses high-frequency circulating currents between modules.

[0070] In the AC / DC module control strategy, the current inner loop includes a positive-sequence current regulator, a negative-sequence current regulator, and a zero-sequence current regulator. The zero-sequence current regulator also includes zero-sequence current DC component, zero-sequence current power frequency component, zero-sequence current third harmonic component, zero-sequence current sixth harmonic component regulation, etc., to suppress the low-frequency circulating current of the AC / DC module in parallel.

[0071] The coordination controller is connected to the touch screen through the serial port or network port. The touch screen displays the home page, parameter setting page, module information page, data curve page, fault information page, etc.; the input terminal of the coordination controller is connected to the emergency stop button, AC circuit breaker status, DC circuit breaker status and other feedback signals; the output terminal of the coordination controller is connected to the operation indicator light, fault indicator light, cabinet door fan and other control signals.

[0072] In an embodiment of the present application, when the coordination controller receives communication data corresponding to a certain ID, judging the online status of the AC / DC module of the ID also includes: if the coordination controller fails to receive the communication data of the ID within a continuous setting time, the AC / DC module of the ID is in an offline state.

[0073] In an optional embodiment, when the coordination controller receives communication data corresponding to a certain ID, if the communication data of the ID is not received for 3 consecutive seconds, the AC / DC module of the ID is in an offline state.

[0074] In the embodiment of the present application, the control message sent by the coordination controller to the AC / DC module that is online and not faulty includes at least the working mode, start / stop, reset, power command, and voltage command;

[0075] The AC / DC modular converter has the following operating modes: PQ constant power operating mode, UDC DC voltage stabilization operating mode, and VF AC voltage stabilization operating mode.

[0076] In the embodiment of the present application, the AC / DC modular converter operates in the PQ constant power working mode, including: setting each AC / DC module to work in the PQ constant power working mode, and coordinating the controller to evenly distribute power to the online and non-faulty AC / DC modules according to the active power instruction and reactive power instruction of the host computer; specifically, the active power instruction Pref_i and the reactive power instruction Qref_i of each non-faulty module are respectively expressed as:

[0077] Pref_i=Pref / MK_OK_Num

[0078] Qref_i=Qref / MK_OK_Num

[0079] Among them, Pref is the active power command, Qref is the reactive power command, and MK_OK_Num is the number of non-faulty modules.

[0080] When any AC / DC module is offline, the AC / DC module automatically detects the loss of the coordination controller control message and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module;

[0081] When any AC / DC module fails, the AC / DC module will automatically shut down, the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will reallocate the power instructions to the online and non-faulty AC / DC modules.

[0082] In the embodiment of the present application, the AC / DC modular converter operates in the UDC DC voltage regulation working mode, including: adopting the UDC droop mode in parallel, the master-slave working mode, setting the master AC / DC module to work in the UDC DC voltage regulation working mode, and setting the slave AC / DC module to work in the UDC droop working mode;

[0083] It should be noted that the DC voltage droop coefficient of the AC / DC module is set large enough to eliminate the influence of the DC voltage sampling error, and the no-load active circulating current is small enough.

[0084] In the embodiment of the present application, the total active power of the AC / DC modular converter is determined by the load or distributed power source connected to the DC side. The coordination controller counts the total active power sent by all online modules and distributes it evenly to the online and non-faulty AC / DC modules according to the reactive power instruction of the host computer; specifically,

[0085] Pref_i=SYS_P_PCS / MK_OK_Num

[0086] Among them, SYS_P_PCS is the total active power.

[0087] When any slave AC / DC module is offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller redistributes the power command to the online and non-faulty AC / DC modules; specifically,

[0088] Qref_i=Qref / MK_OK_Num

[0089] When any slave AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will redistribute the power command to the online and non-faulty AC / DC modules;

[0090] When any main AC / DC module is offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the UDC voltage regulation working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module;

[0091] When any main AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the UDC voltage regulation working mode, and the coordination controller redistributes the power instructions to the online and non-faulty AC / DC modules.

[0092] In the embodiment of the present application, the AC / DC modular converter operates in the VF AC voltage stabilization working mode including:

[0093] Adopt VF droop mode parallel connection, master-slave working mode, set the master AC / DC module to work in VF AC voltage regulation working mode, set the slave AC / DC module to work in VF droop working mode; before starting operation, the coordination controller actively sends phase synchronization signals to each AC / DC module;

[0094] It should be noted that in the VF droop working mode, the voltage droop coefficient of the AC / DC module or the grid-side virtual impedance is set large enough to eliminate the influence of the AC voltage sampling error, and the no-load reactive circulating current is small enough.

[0095] The total active power and total reactive power of the AC / DC modular converter are determined by the load or distributed power source connected to the AC side. The coordination controller counts the total active power and total reactive power sent by all online modules and evenly distributes them to the online and non-faulty AC / DC modules. Specifically,

[0096] Pref_i=SYS_P_PCS / MK_OK_Num

[0097] Qref_i=SYS_Q_PCS / MK_OK_Num

[0098] Among them, SYS_Q_PCS is the total reactive power.

[0099] In the embodiment of the present application, it also includes:

[0100] When any slave AC / DC module goes offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller reallocates the power instructions to the online and non-faulty AC / DC modules.

[0101] When any slave AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will reallocate power commands to online and non-faulty AC / DC modules.

[0102] When any main AC / DC module is offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the VF AC voltage stabilization working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module;

[0103] When any main AC / DC module fails, the AC / DC module will automatically shut down. The number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the VF AC voltage regulation working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module.

[0104] The above is a schematic scheme of a modular converter building block parallel coordinated control method of this embodiment. It should be noted that the technical scheme of this modular converter building block parallel coordinated control system and the technical scheme of the modular converter building block parallel coordinated control method described above belong to the same concept, and the details of the technical scheme of the modular converter building block parallel coordinated control system not described in detail in this embodiment can all be referred to the description of the technical scheme of the modular converter building block parallel coordinated control method described above.

[0105] In this embodiment, a modular converter building block parallel coordinated control system is provided. The AC ports of all parallel modules of the modular converter are connected to the AC busbar, and the DC ports are connected to the DC busbar; the AC busbar is connected to the AC circuit breaker, the DC busbar is connected to the DC fault protection unit, and the DC fault protection unit is connected to the DC circuit breaker. The system includes:

[0106] The data identification module is used for the parallel module to connect different AC / DC modules in parallel. Different AC / DC modules use different IDs to identify the operation data actively periodically sent by the AC / DC modules.

[0107] The judgment module is used for establishing a fast communication mode between multiple parallel AC / DC modules and the coordination controller. The coordination controller presets the maximum number of AC / DC module ID numbers. When the coordination controller receives communication data corresponding to a certain ID, it judges the online status of the AC / DC module of the ID.

[0108] The fault statistics module is used to coordinate the controller to parse the received operation data of the online AC / DC module and obtain the fault code of each module when the AC / DC module is in the online state, and count the AC / DC modules with fault codes not zero to obtain the number of non-faulty modules;

[0109] The coordination control module is used to coordinate the controller to send control messages to the AC / DC modules that are online and not at fault, and perform periodic control on the AC / DC modules.

[0110] This embodiment further provides a computing device, which is applicable to the modular converter building block parallel coordinated control method, including:

[0111] Memory and processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the modular converter building block parallel coordinated control method proposed in the above embodiment.

[0112] This embodiment further provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for implementing modular converter building block parallel coordinated control as proposed in the above embodiment is implemented.

[0113] The storage medium proposed in this embodiment and the method for implementing modular converter building block parallel coordinated control proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0114] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0115] Example 2

[0116] Reference Figure 6 to Figure 8 , is an embodiment of the present invention. This embodiment is different from the first embodiment in that this embodiment verifies the beneficial effects of the present invention through specific test experiments.

[0117] In this embodiment, an AC / DC converter with 5 modules connected in parallel is used as the test device, and the IDs of the 5 modules are 0 to 4 respectively; a high-power AC / DC converter is used as the accompanying test device. When the test device works in the VF AC voltage stabilization working mode, its DC side needs to be connected to the DC power supply in advance. When 4 modules are inserted into the test device as a whole, the number of online modules is identified as 4, and the capacity of the whole machine is 200kVA; when 5 modules are inserted into the test device as a whole, the number of online modules is identified as 5, and the capacity of the whole machine automatically becomes 250kVA, realizing flexible configuration of the converter capacity. In this embodiment, the actual power data of the modules recorded are all positive with the AC / DC module rectification.

[0118] like Figure 6 As shown, where: 1) When the 250kVA test equipment operates in PQ constant power working mode;

[0119] The high-power AC / DC test equipment is operated in the UDC voltage stabilization mode to establish a DC voltage of DC750V. The equipment under test is operated in the PQ constant power mode, the total active power command is set to 150kW, and the actual power data of the five modules are recorded, as shown in Table 1:

[0120] Table 1 Power data

[0121] Module ID 0 1 2 3 4 Active power (kW) 30.5 30.2 29.7 29.6 30.1

[0122] At this time, unplug the parallel communication line of the module with ID=1, and the module with ID=1 stops working due to a fault. The actual power data of the five modules are recorded, as shown in Table 2:

[0123] Table 2 Power data

[0124] Module ID 0 1 2 3 4 Active power (kW) 37.9 0 37.1 37.2 37.6

[0125] It can be seen from Table 1 and Table 2 that in the PQ constant power working mode, within the capacity range of the tested equipment, the output power is not affected, and the present invention can improve the reliability of the equipment, while in the traditional solution, module failure will cause the equipment to shut down.

[0126] 2) When the 250kVA equipment under test is running in UDC voltage stabilization mode;

[0127] The device under test is operated in the UDC voltage stabilization mode to establish a DC voltage of DC750V. The high-power AC / DC test equipment is operated in the PQ constant power mode and connected to the grid as the DC electronic load of the device under test. The total active power command is set to -150kW. The actual power data of the five modules of the device under test are recorded, as shown in Table 3:

[0128] Table 3 Power data

[0129] Module ID 0 1 2 3 4 Active power (kW) 29.1 29.4 30.8 32.3 32.2

[0130] At this time, unplug the parallel communication line of the module with ID=0 (main module), the module with ID=0 fails and stops, and the module with ID=1 automatically becomes the main module. The actual power data of the five modules are recorded, as shown in Table 4:

[0131] Table 4 Power data

[0132] Module ID 0 1 2 3 4 Active power (kW) 0 36.6 38.4 39.7 39.5

[0133] It can be seen from Table 3 and Table 4 that in the UDC voltage stabilization working mode, within the capacity range of the tested equipment, the DC load is not affected, and the present invention can improve the reliability of the equipment. However, in the traditional solution, a main module failure will cause the DC voltage to collapse and the equipment to shut down due to failure.

[0134] like Figure 7 As shown in the figure, when the 250kVA test equipment operates in the VF AC voltage stabilization working mode,

[0135] The output voltage of the 50kW DC power supply is DC750V; the tested equipment is operated in the VF AC voltage stabilization working mode, and the three-phase AC voltage is AC380V. The AC voltage waveform at startup is shown in Figure 8 The high-power AC / DC test equipment is operated in the PQ constant power working mode and connected to the AC power grid established by the test equipment. The total active power command is set to 150kW as the AC electronic load of the test equipment. The actual power data of the five modules of the test equipment are recorded, as shown in Table 5:

[0136] Table 5 Power data

[0137] Module ID 0 1 2 3 4 Active power (kW) -28.5 -27.6 -30.4 -31.5 -32.3

[0138] At this time, unplug the parallel communication line of the module with ID=0 (main module), the module with ID=0 fails and stops, and the module with ID=1 automatically becomes the main module. The actual power data of the five modules are recorded, as shown in Table 6:

[0139] Table 6 Power data

[0140] Module ID 0 1 2 3 4 Active power (kW) 0 -36.2 -38.3 -39.2 -36.9

[0141] It can be seen from Table 3 and Table 4 that in the VF AC voltage stabilization working mode, within the capacity range of the tested equipment, the AC load is not affected, while in the traditional solution, the failure of the main module will cause the AC voltage frequency to collapse and the equipment to shut down. In the VF AC voltage stabilization working mode, the present invention adopts the droop mode parallel connection, and each module has the voltage source characteristic, which can improve the carrying capacity and reliability of the whole machine.

[0142] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A modular converter building block parallel coordinated control method, characterized in that: The AC ports of all parallel modules of the modular converter are connected to the AC busbar, and the DC ports are connected to the DC busbar; the AC busbar is connected to the AC circuit breaker, the DC busbar is connected to the DC fault protection unit, and the DC fault protection unit is connected to the DC circuit breaker. The method includes: The parallel connection module connects different AC / DC modules in parallel, and the different AC / DC modules use different IDs to identify the operation data actively periodically sent by the AC / DC modules; The multiple parallel AC / DC modules establish a fast communication mode with the coordination controller, and the coordination controller presets a maximum number of AC / DC module ID numbers; when the coordination controller receives communication data corresponding to a certain ID, it determines the online status of the AC / DC module of the ID; When the AC / DC module is in an online state, the coordination controller parses the received operation data of the online AC / DC module and obtains the fault code of each module, counts the AC / DC modules whose fault codes are not zero, and obtains the number of non-faulty modules; The coordination controller sends a control message to an online and non-faulty AC / DC module to perform periodic control on the AC / DC module.

2. The modular converter building block parallel coordinated control method according to claim 1, characterized in that: When the coordination controller receives communication data corresponding to a certain ID, judging the online status of the AC / DC module of the ID also includes: if the coordination controller fails to receive the communication data of the ID within a continuous setting time, the AC / DC module of the ID is in an offline state.

3. The modular converter building block parallel coordinated control method according to claim 2, characterized in that: The control message sent by the coordination controller to the AC / DC module that is online and not at fault includes at least the working mode, start / stop, reset, power command, and voltage command; The AC / DC modular converter has the following operating modes: PQ constant power operating mode, UDC DC voltage stabilization operating mode, and VF AC voltage stabilization operating mode.

4. The modular converter building block parallel coordinated control method according to claim 3, characterized in that: The AC / DC modular converter is operated in the PQ constant power working mode, including: setting each AC / DC module to work in the PQ constant power working mode, and coordinating the controller to evenly distribute power to the online and non-faulty AC / DC modules according to the active power instruction and reactive power instruction of the host computer; When any AC / DC module is offline, the AC / DC module automatically detects the loss of the coordination controller control message and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module; When any AC / DC module fails, the AC / DC module will automatically shut down, the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will reallocate the power instructions to the online and non-faulty AC / DC modules.

5. The modular converter building block parallel coordinated control method according to claim 3 or 4, characterized in that: The AC / DC modular converter operates in the UDC DC voltage regulation mode, including: parallel connection in the UDC droop mode, master-slave working mode, setting the master AC / DC module to work in the UDC DC voltage regulation mode, and setting the slave AC / DC module to work in the UDC droop working mode; The total active power of the AC / DC modular converter is determined by the load or distributed power source connected to the DC side. The coordination controller counts the total active power sent by all online modules and evenly distributes it to the online and non-faulty AC / DC modules according to the reactive power instruction of the host computer. When any slave AC / DC module goes offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller reallocates the power instructions to the online and non-faulty AC / DC modules. When any slave AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will redistribute the power command to the online and non-faulty AC / DC modules; When any main AC / DC module is offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the UDC voltage regulation working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module; When any main AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the UDC voltage regulation working mode, and the coordination controller redistributes the power instructions to the online and non-faulty AC / DC modules.

6. The modular converter building block parallel coordinated control method according to claim 5, characterized in that: The AC / DC modular converter operates in the VF AC voltage stabilization mode including: Adopt VF droop mode parallel connection, master-slave working mode, set the master AC / DC module to work in VF AC voltage regulation working mode, set the slave AC / DC module to work in VF droop working mode; before starting operation, the coordination controller actively sends phase synchronization signals to each AC / DC module; The total active power and total reactive power of the AC / DC modular converter are determined by the load or distributed power source connected to the AC side. The coordination controller counts the total active power and total reactive power sent by all online modules and evenly distributes them to the online and non-faulty AC / DC modules.

7. The modular converter building block parallel coordinated control method according to claim 6, characterized in that: Also includes: When any slave AC / DC module goes offline, the AC / DC module automatically detects the loss of the coordination controller control message and shuts down due to a fault; The number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller redistributes the power instructions to the online and non-faulty AC / DC modules. When any slave AC / DC module fails, the AC / DC module will automatically shut down; the number of non-faulty modules in the coordination controller will be reduced by 1, and the coordination controller will reallocate power commands to online and non-faulty AC / DC modules. When any main AC / DC module is offline, the AC / DC module automatically detects that the control message of the coordination controller is lost and shuts down due to a fault; the number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the VF AC voltage stabilization working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module; When any main AC / DC module fails, the AC / DC module will automatically shut down. The number of non-faulty modules in the coordination controller is reduced by 1, and the coordination controller sets the AC / DC module with the next ID as the main module in turn, working in the VF AC voltage regulation working mode, and the coordination controller redistributes the power command to the online and non-faulty AC / DC module.

8. A modular converter building block parallel coordinated control system, characterized in that: The AC ports of all parallel modules of the modular converter are connected to the AC busbar, and the DC ports are connected to the DC busbar; the AC busbar is connected to the AC circuit breaker, the DC busbar is connected to the DC fault protection unit, and the DC fault protection unit is connected to the DC circuit breaker. The system includes: A data identification module, used for the parallel connection module to connect different AC / DC modules in parallel, and the different AC / DC modules use different IDs to identify the operation data actively periodically sent by the AC / DC modules; A judgment module is used for establishing a fast communication mode between the plurality of parallel AC / DC modules and the coordination controller, wherein the coordination controller presets a maximum number of AC / DC module ID numbers; when the coordination controller receives communication data corresponding to a certain ID, it judges the online status of the AC / DC module of the ID; A fault statistics module, used for, when the AC / DC module is in an online state, the coordination controller to parse the received operation data of the online AC / DC module and obtain the fault code of each module, count the AC / DC modules whose fault codes are not zero, and obtain the number of non-faulty modules; The coordination control module is used for the coordination controller to send control messages to the AC / DC modules that are online and not at fault, and to perform periodic control on the AC / DC modules.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the modular converter building block parallel coordinated control method described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the modular converter building block parallel coordinated control method according to any one of claims 1 to 7.

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