Double-converter parallel topological structure of alternating-current power transmission system and control method

Abstract

The embodiment of the invention provides a double-converter parallel topological structure of an alternating current power transmission system and a control method. The structure comprises a first converter, a second converter and a power transmission control unit, wherein the first current converter is used for controlling the voltage and the frequency of the alternating current power transmission system, the second current converter is used for controlling the active power and the reactive power of the alternating current power transmission system, and the power transmission control unit is used for control management; the first current converter and the second current converter can control mutual conversion of first frequency three-phase electric energy and second frequency three-phase electric energy, wherein the first frequency is greater than the second frequency; the same side of the first current converter and the second current converter adopts a three-phase parallel connection mode; one ends of the first converter and the second converter which are connected in parallel are connected to a first alternating current system, and the other ends are connected to a second alternating current system; according to the invention, the transmission capability of the converter station can be significantly improved in a sending-out scene after collection of large-capacity new energy.

Description

Technical Field

[0001] The present application relates to the field of power transmission systems, and in particular to a dual-converter parallel topology structure and a control method for an AC power transmission system. Background Art

[0002] At present, large-scale development and utilization of new energy has become a trend in global energy development. However, due to geographical factors, many new energy power stations are connected to the grid at a long distance. Conventional industrial frequency AC methods have certain limitations in such long-distance transmission scenarios, mainly manifested in poor transmission stability and low capacity limit. Therefore, flexible low-frequency AC transmission technology has gradually been applied to new energy grid connection. Compared with industrial frequency AC, flexible low-frequency AC transmission technology has a larger transmission capacity and a longer transmission distance, which can effectively improve the stability and transmission efficiency of long-distance new energy grid connection and meet the needs of large-scale new energy transmission.

[0003] However, with the increase in transmission capacity, the difficulty of designing low-frequency transformers in flexible low-frequency AC systems has increased significantly. Since low-frequency transformers need to adapt to large-capacity and high-power transmission environments, their size and weight have also increased accordingly, which not only increases equipment costs, but also brings higher requirements for installation and maintenance. Therefore, how to reduce the design requirements of low-frequency transformers and reduce their size and weight by optimizing the topology of the converter has become a key technical problem in improving the efficiency of flexible low-frequency AC transmission systems.

[0004] At present, in the existing technology, the interconnection of regional power grids and the long-distance transmission of offshore renewable energy have gradually adopted flexible low-frequency AC transmission systems to achieve aggregation and grid connection. However, these systems generally adopt a single converter valve structure, and still face the problem of excessive transformer size and weight when the capacity is large. Common flexible low-frequency transmission AC switching stations are mostly based on a single converter valve solution. Although this structure can achieve a certain low-frequency transmission effect, in large-capacity application scenarios, the physical volume and weight of the low-frequency transformer increase too quickly, making it difficult to meet actual application requirements. Therefore, the existing technical solutions have obvious limitations in large-scale renewable energy grid connection, and it is difficult to balance the transmission capacity with the requirements of equipment volume and weight. Summary of the invention

[0005] In response to the problems in the prior art, the present application provides a dual-converter parallel topology structure and control method for an AC power transmission system, which can significantly improve the transmission capacity of the converter station in the transmission scenario after large-capacity new energy is collected.

[0006] In order to solve at least one of the above problems, the present application provides the following technical solutions:

[0007] According to a first aspect of an embodiment of the present application, the present application provides a dual-converter parallel topology structure of an AC power transmission system, comprising:

[0008] A first converter, a second converter and a power transmission control unit;

[0009] The first converter is used to control the voltage and frequency of the AC power transmission system, the second converter is used to control the active power and reactive power of the AC power transmission system, and the power transmission control unit is used to control and manage the first converter and the second converter;

[0010] The first converter and the second converter are both capable of controlling the mutual conversion of three-phase electric energy of a first frequency and three-phase electric energy of a second frequency, wherein the first frequency is greater than the second frequency;

[0011] The first converter and the second converter are connected in three-phase parallel on the same side;

[0012] One end of the first converter and the second converter connected in parallel is connected to the first AC system, and the other end is connected to the second AC system.

[0013] According to any embodiment of the present application, the parallel connection mode of the first converter and the second converter includes using a parallel reactor to balance current distribution.

[0014] According to any embodiment of the present application, the first converter and the second converter work in coordination through a synchronization control unit to achieve phase synchronization and power quality between different frequencies.

[0015] According to any implementation of the present application, the synchronization control unit includes:

[0016] A voltage synchronization controller, used to synchronize the output voltage of the first converter with the voltage of the second AC system;

[0017] A power controller is used to adjust the active power and reactive power output of the second converter.

[0018] According to any embodiment of the present application, the input sides of the first converter and the second converter are both connected to a common DC bus for centralized power supply.

[0019] According to any embodiment of the present application, the common DC bus includes a filtering device for suppressing current pulsation to reduce voltage fluctuations and improve system stability.

[0020] According to a second aspect of an embodiment of the present application, the present application provides a control method for a dual-converter parallel topology structure of an AC power transmission system, which is applied to a power transmission control unit of a dual-converter parallel topology structure of an AC power transmission system, comprising:

[0021] Performing voltage / frequency control on the first converter so that the output voltage of the first converter is consistent with the target voltage of the AC system;

[0022] Performing active power / reactive power control on the second converter so as to optimize the power distribution of the system to a preset state;

[0023] The first converter and the second converter are coordinated and controlled by a synchronous control unit, and a parallel reactor is used to balance the current distribution of the first converter and the second converter, so that the phase synchronization and power quality between the first converter and the second converter remain stable.

[0024] According to a third aspect of an embodiment of the present application, the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the control method of the dual-converter parallel topology structure of the AC power transmission system are implemented.

[0025] According to a fourth aspect of an embodiment of the present application, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the control method for a dual-converter parallel topology structure of an AC power transmission system.

[0026] According to a fifth aspect of an embodiment of the present application, the present application provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the steps of the control method of the dual-converter parallel topology structure of the AC power transmission system.

[0027] It can be seen from the above technical scheme that the present application provides a dual-converter parallel topology structure and control method of an AC transmission system, the structure comprising: a first converter, a second converter and a transmission control unit; wherein the first converter is used to control the voltage and frequency of the AC transmission system, the second converter is used to control the active power and reactive power of the AC transmission system, and the transmission control unit is used to control and manage the first converter and the second converter; the first converter and the second converter can both control the mutual conversion of three-phase electric energy of the first frequency and three-phase electric energy of the second frequency, wherein the first frequency is greater than the second frequency; the same side of the first converter and the second converter adopts a three-phase parallel connection method; one end of the parallel first converter and the second converter is connected to the first AC system, and the other end is connected to the second AC system; the present application can significantly improve the transmission capacity of the converter station in the transmission scenario after large-capacity new energy is collected. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a schematic diagram of the voltage and frequency control structure of the first converter in an embodiment of the present application;

[0030] Figure 2 Schematic diagram of active power and reactive power control structure of the second converter in an embodiment of the present application;

[0031] Figure 3 This is a schematic diagram of the application of a dual-converter parallel topology structure in an AC power transmission system according to an embodiment of the present application;

[0032] Figure 4 A schematic flow chart of a control method for a dual-converter parallel topology structure of an AC power transmission system in an embodiment of the present application;

[0033] Figure 5 It is a schematic diagram of the structure of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] The acquisition, storage, use, and processing of data in the technical solution of this application comply with the relevant provisions of national laws and regulations.

[0036] Taking into account the obvious limitations of existing technical solutions in large-scale renewable energy grid connection and the difficulty in balancing the transmission capacity with the requirements of equipment volume and weight, the present application provides a dual-converter parallel topology structure and control method for an AC transmission system, which significantly improves the transmission capacity of the converter station in the transmission scenario after large-capacity renewable energy is collected.

[0037] The dual-converter parallel topology structure of the AC power transmission system provided in this application includes:

[0038] A first converter, a second converter and a power transmission control unit;

[0039] The first converter is used to control the voltage and frequency of the AC power transmission system, the second converter is used to control the active power and reactive power of the AC power transmission system, and the power transmission control unit is used to control and manage the first converter and the second converter;

[0040] The first converter and the second converter are both capable of controlling the mutual conversion of three-phase electric energy of a first frequency and three-phase electric energy of a second frequency, wherein the first frequency is greater than the second frequency;

[0041] The first converter and the second converter are connected in three-phase parallel on the same side;

[0042] One end of the first converter and the second converter connected in parallel is connected to the first AC system, and the other end is connected to the second AC system.

[0043] Specifically, the first converter takes voltage and frequency as control targets, and is mainly responsible for regulating the system voltage and frequency. It can maintain a stable voltage output and adjust the frequency when necessary to adapt to different loads and external environmental changes. The second converter takes active power and reactive power as control targets, and achieves system power balance by adjusting the system's active power (actually transmitted energy) and reactive power (energy to maintain voltage stability), ensuring improved power quality. Such a dual control target design can provide higher flexibility and stability in a diverse power demand environment.

[0044] Furthermore, in this topology, both the first and second converters support three-phase power conversion at different frequencies to achieve flexible conversion between high-frequency and low-frequency power. Specifically, by defining the first frequency to be higher than the second frequency, energy exchange can be performed between different frequencies, so that the system can adapt to longer-distance power transmission needs, meet the scenario requirements of long-distance power transmission and reduce transmission losses. For example, the first frequency may represent a common power grid frequency (such as 50Hz or 60Hz), while the second frequency is a lower frequency that is more suitable for long-distance transmission in a specific scenario. Through the frequency conversion, the system can maintain efficient energy transmission during power transmission and grid connection.

[0045] In terms of implementation, the same side of the first and second converters adopts a three-phase parallel connection method, so that the two can share the current at the same time, thereby reducing the load pressure of a single converter and extending the life of the equipment. The three-phase parallel connection structure not only allows the system to achieve a larger power capacity, suitable for large-scale new energy collection and power transmission application scenarios, but also improves the redundancy and reliability of the system. In addition, one end of the first converter and the second converter in parallel is connected to the first AC system, and the other end is connected to the second AC system, realizing energy conversion and stable transmission between the systems. The first AC system and the second AC system can represent the input and output ends of the power grid, respectively, or two AC power systems with different frequencies. The parallel topology structure can therefore achieve stable and efficient power transmission between different AC systems.

[0046] Preferably, in an optional embodiment, the parallel connection mode of the first converter and the second converter includes using a parallel reactor to balance current distribution.

[0047] Specifically, the shunt reactor is designed as a balancing element between two converters. When the first converter is controlled by voltage and frequency, and the second converter is controlled by active power and reactive power, the system may have uneven current distribution during operation due to the load difference of the converters. The role of the shunt reactor is to balance the current distribution between the two by adjusting the reactance value, so that the current carried by each converter matches its capacity. This balancing mechanism ensures that the system can still operate smoothly even in the case of large load changes.

[0048] In actual implementation, the shunt reactors can be placed at the same side access terminals of the first and second converters (not shown) to maximize their balancing effect. Each converter is equipped with an independent current feedback control loop, which realizes accurate current distribution by real-time monitoring of the output current of the converter and combining the adjustment of the shunt reactor.

[0049] For example, in large-capacity transmission scenarios where new energy sources are integrated, the system often needs to cope with rapidly changing power loads and frequency requirements. The introduction of shunt reactors can achieve stable current distribution during the transmission of large currents, thereby avoiding problems such as voltage fluctuations or converter overload caused by current differences.

[0050] In an optional embodiment, the first converter and the second converter work in coordination via a synchronization control unit to achieve phase synchronization and power quality between different frequencies.

[0051] Specifically, the synchronization control unit may include a phase synchronization controller and a power quality controller. The phase synchronization controller is responsible for monitoring and adjusting the output phase of the two converters to ensure that their output currents maintain the same phase angle when operating in parallel. Through real-time phase detection and feedback control, the phase synchronization controller can automatically adjust the output phase of the converter to eliminate phase deviations caused by load changes or frequency fluctuations.

[0052] In actual operation, the phase synchronization controller continuously detects the voltage and current phases of the first converter and the second converter, and adjusts their output phases in real time through a control algorithm (such as a closed-loop feedback algorithm based on proportional-integral-differential control). If a phase difference is detected, the synchronization controller will send an adjustment instruction to the corresponding converter to keep the outputs of the two consistent, thereby achieving phase synchronization. This phase synchronization mechanism is particularly important in large-scale renewable energy grid connection or frequency conversion scenarios, because phase asynchrony may cause energy loss, uneven equipment load, or severe system oscillations.

[0053] On the other hand, the power quality controller is responsible for maintaining the power quality of the system, including suppressing harmonics, voltage fluctuations and frequency fluctuations. By detecting the output voltage and current waveforms, the power quality controller can analyze and adjust the output of the converter to reduce harmonic content and power quality issues.

[0054] In addition, the synchronous control unit can also ensure the coordination and consistency of the two converters during operation by establishing a master-slave control mechanism. For example, the first converter is set as the master converter to control the voltage and frequency output, while the second converter is set as the slave converter to follow the phase and voltage changes of the master converter to adjust the power. In this way, the first converter can output stable electric energy on the basis of maintaining the stability of the system voltage and frequency, while the second converter is responsible for adjusting the active and reactive power under the guidance of the master converter, thereby optimizing the overall system.

[0055] In an optional embodiment, the synchronization control unit includes:

[0056] A voltage synchronization controller, used to synchronize the output voltage of the first converter with the voltage of the second AC system;

[0057] A power controller is used to adjust the active power and reactive power output of the second converter.

[0058] The main function of the voltage synchronization controller is to synchronize the output voltage of the first converter with the voltage of the second AC system.

[0059] The voltage synchronization controller adopts the closed-loop control principle to detect the difference between the output voltage of the first converter and the voltage of the second AC system in real time, and adjusts the output of the first converter through feedback to ensure that the voltage always remains consistent. For example, the voltage synchronization controller can adjust the output of the converter through a proportional-integral (PI) controller so that its voltage is aligned with the voltage of the second AC system in phase and amplitude, ensuring the smooth transmission of electric energy from the low-frequency system to the high-frequency system, which helps to reduce energy loss and voltage fluctuations.

[0060] In a specific implementation, the voltage synchronization controller can also be combined with a phase-locked loop (PLL) to detect and synchronize the phases of the two voltages. The PLL tracks the phase changes of the second AC system and feeds the phase information back to the first converter to ensure that the output voltage is completely synchronized with the second AC system. In this way, the first converter can respond quickly and maintain synchronization regardless of the voltage amplitude or phase.

[0061] Secondly, the power controller is used to adjust the active power and reactive power output of the second converter to meet the power demand of the system and improve the power quality. The power controller automatically adjusts the active power (actual power transmitted) and reactive power (energy used to maintain system voltage stability) of the second converter by monitoring the power demand of the system in real time.

[0062] In a specific implementation, the power controller can use an independent PI controller to adjust the active power and reactive power separately. The power controller continuously monitors the deviation between the actual power output and the target power, and adjusts the output of the converter according to the deviation. For example, when the system needs more active power, the power controller will increase the active output of the second converter; when the system voltage needs to be stable, the power controller will appropriately increase the reactive power output to maintain the voltage level. In addition, the power controller can also use reactive power compensation technology, such as instantaneous reactive power theory, to reduce harmonics and improve power quality, ensuring that the power quality of the entire system output meets the requirements.

[0063] In an optional embodiment, the input sides of the first converter and the second converter are both connected to a common DC bus for centralized power supply.

[0064] The common DC bus serves as a DC power source collection point for the entire system, providing a stable DC power source for the first converter and the second converter. The common bus can be connected to a DC transmission network, a photovoltaic power generation system, a wind power generation system, and other new energy DC power sources. Through the centralized DC power supply design, the power input can be managed uniformly to ensure that the two converters operate at the same DC voltage and achieve the optimal allocation of power resources. In addition, the centralized power supply design can also simplify the system structure and reduce energy loss caused by multiple power conversions.

[0065] In terms of workflow, the common DC bus first obtains power from the upstream DC power supply, and eliminates the harmonic and pulsating components in the current through the DC filter device to provide a smooth DC input. Subsequently, the first converter and the second converter obtain DC power from the common bus respectively, and perform power conversion according to their own control targets. The first converter is mainly responsible for the regulation of voltage and frequency, while the second converter focuses on the control of active power and reactive power. Through this centralized power supply method, the two converters can work under the same DC input conditions, thereby achieving higher synchronization and coordination.

[0066] In an optional embodiment, the common DC bus includes a filtering device for suppressing current pulsation to reduce voltage fluctuations and improve system stability.

[0067] The filter device can filter out the current pulsation and harmonic interference caused by the fluctuation of new energy input or load change in the DC bus, ensuring that the converter receives a stable DC power supply. For example, the filter device can be a combination of capacitors, inductors or active filters, placed on the DC bus, and eliminate the pulsation component in the current in real time.

[0068] In order to further illustrate the present solution, the present application also provides a specific application example of using the control device of the dual-converter parallel topology structure of the AC power transmission system to realize the control system of the dual-converter parallel topology structure of the AC power transmission system, which specifically includes the following contents:

[0069] Figure 1 The voltage and frequency control structure of the first converter is shown, which is specifically used to adjust the voltage output and frequency response of the system. This control structure adopts a dual closed-loop control design, including inner loop current control and outer loop voltage control to ensure the stability of the output voltage and frequency. The system uses a proportional integral (PI) controller to accurately adjust the current and voltage of the d-axis and q-axis. The d-axis and q-axis components are shown in the figure, and the corresponding feedback processing is performed through the inductor element (ωL) to suppress interference and ensure the output voltage (u d and u q ) and the reference voltage (u d_ref and u q_ref ) to remain consistent.

[0070] In the specific control process, the voltage deviation of the d-axis and q-axis is processed by the PI controller to generate the corresponding current reference value (i d_ref and i q_ref ), and then convert these reference values ​​into actual current output through the current controller, and finally feed back to the output end of the inverter. This design can dynamically adjust the voltage and frequency of the system, effectively cope with load fluctuations, and ensure the stable operation of the system.

[0071] Figure 2 The active power and reactive power control structure of the second converter is shown. Its control goal is to adjust the output active power (P) and reactive power (Q) to ensure the power balance and power quality of the system. This structure also uses a PI controller to adjust the power output, where the d-axis controls the active power and the q-axis controls the reactive power. The control process first calculates the reference value of the active power and reactive power (P ref and Q ref ) is compared with the actual output power, and the error is adjusted by the PI controller to generate the current reference value (i d_ref and i q_ref ), these reference values ​​are further used to control the current output of the d-axis and q-axis.

[0072] In this structure, the power control loop performs feedback regulation on the d-axis and q-axis currents through the inductor element (ωL) to ensure the stability of the power output. Ultimately, through this regulation process, the control system enables the converter to dynamically respond to system requirements, achieve precise control of active and reactive power, and improve system stability and power quality.

[0073] Figure 3 The schematic diagram of the application of the dual-converter parallel topology structure in the AC power transmission system in this application is shown, which is specifically used to realize the conversion of low-frequency AC power and high-frequency AC power to meet the needs of different power grid systems. The figure shows a dual-converter structure, each converter is powered by a 220kV, 20Hz low-frequency voltage source on the input side, and converts it to a 220kV, 50Hz high-frequency voltage on the output side, and finally connected to the power grid.

[0074] exist Figure 3 In the figure, the two "AC / AC" modules represent two inverters, which are responsible for converting low-frequency AC power (20Hz) into high-frequency AC power (50Hz). By transmitting 20Hz low-frequency power, the loss in long-distance transmission can be reduced, and it will be converted to 50Hz before connecting to the power grid to adapt to the standard power grid frequency.

[0075] The input and output ends of each converter are regulated by corresponding transformers. The transformer on the input side is used to adapt the 220kV low-frequency AC power to ensure that it is suitable for entering the AC / AC conversion unit. The transformer on the output side is used to match the voltage output to the grid to ensure that the 220kV, 50Hz high-frequency power can be stably transmitted to the grid.

[0076] The above dual-converter parallel structure not only improves the capacity and stability of the system, but also ensures that the two converters can work synchronously during load fluctuations and frequency conversion to achieve stable power output.

[0077] In order to significantly improve the transmission capacity of the converter station in the transmission scenario after the large-capacity new energy is collected, the present application provides an embodiment of a control method for a dual-converter parallel topology structure of an AC power transmission system, and a transmission control unit for a dual-converter parallel topology structure of an AC power transmission system, see Figure 4 The control method of the dual-converter parallel topology structure of the AC power transmission system specifically includes the following contents:

[0078] Step S101: performing voltage / frequency control on a first converter so that an output voltage of the first converter is consistent with a target voltage of an AC system.

[0079] Step S102: performing active power / reactive power control on the second converter to optimize the power distribution of the system to a preset state.

[0080] Step S103: coordinately control the first converter and the second converter through a synchronization control unit, and use a parallel inductor to balance the current distribution between the first converter and the second converter, so as to keep the phase synchronization and power quality between the first converter and the second converter stable.

[0081] The method provided in the present application first controls the voltage and frequency of the first converter so that its output voltage is consistent with the target voltage of the AC system. Through this control, the first converter can ensure that the voltage level of the system remains stable, thereby meeting the voltage requirements of the power grid and adapting to different load fluctuations.

[0082] At the same time, the active power and reactive power of the second converter are controlled to optimize the power distribution of the system to achieve the preset ideal state. The second converter focuses on adjusting the active and reactive power to ensure the power balance of the system, reduce energy loss, and improve the overall power quality. This control strategy can effectively cope with complex load conditions and ensure that the system can still operate smoothly under changing power supply requirements.

[0083] In addition, the method coordinates the control of the two converters through a synchronous control unit, and configures a parallel reactor between the two to balance the current distribution. The parallel reactor acts as a balancing element, which makes the current distribution of the first converter and the second converter reasonable, avoiding the risk of system instability caused by current imbalance. The synchronous control unit also ensures the phase synchronization of the two converters, so that the overall output power quality of the system remains stable. The innovation of this control method lies in achieving the stability and reliability of the system through the independent realization of dual control objectives (voltage / frequency and active / reactive power) and under the coordination of the synchronous control unit.

[0084] From the above description, it can be seen that the control method of the dual-converter parallel topology structure of the AC transmission system provided in the embodiment of the present application can significantly improve the transmission capacity of the converter station in the transmission scenario after the large-capacity new energy is collected.

[0085] From the hardware level, in order to significantly improve the transmission capacity of the converter station in the transmission scenario after the large-capacity new energy is collected, the present application provides an embodiment of an electronic device for implementing all or part of the content of the control method of the dual-converter parallel topology structure of the AC power transmission system, and the electronic device specifically includes the following content:

[0086] Processor, memory, communication interface and bus; wherein the processor, memory and communication interface communicate with each other through the bus; the communication interface is used to realize information transmission between the control device of the dual converter parallel topology structure of the AC power transmission system and related equipment such as the core business system, user terminal and related database; the logic controller can be a desktop computer, a tablet computer and a mobile terminal, etc., and the present embodiment is not limited thereto. In the present embodiment, the logic controller can be implemented with reference to the embodiment of the control method of the dual converter parallel topology structure of the AC power transmission system in the embodiment, and the embodiment of the control device of the dual converter parallel topology structure of the AC power transmission system, and the contents thereof are incorporated herein, and the repeated parts are not repeated.

[0087] It is understandable that the user terminal may include a smart phone, a tablet electronic device, a network set-top box, a portable computer, a desktop computer, a personal digital assistant (PDA), a vehicle-mounted device, a smart wearable device, etc. Among them, the smart wearable device may include smart glasses, a smart watch, a smart bracelet, etc.

[0088] In practical applications, part of the control method of the dual-converter parallel topology structure of the AC power transmission system can be executed on the electronic device side as described above, or all operations can be completed in the client device. The specific selection can be based on the processing capability of the client device and the limitations of the user's usage scenario. This application does not limit this. If all operations are completed in the client device, the client device may also include a processor.

[0089] The client device may have a communication module (i.e., a communication unit) that can communicate with a remote server to achieve data transmission with the server. The server may include a server on the task scheduling center side, and other implementation scenarios may also include a server on an intermediate platform, such as a server on a third-party server platform that has a communication link with the task scheduling center server. The server may include a single computer device, or a server cluster consisting of multiple servers, or a server structure of a distributed device.

[0090] Figure 5 FIG. 9 is a schematic block diagram of the system structure of the electronic device 9600 according to an embodiment of the present application. Figure 5 As shown, the electronic device 9600 may include a central processor 9100 and a memory 9140; the memory 9140 is coupled to the central processor 9100. It is worth noting that Figure 5 is exemplary; other types of structures may also be used to supplement or replace this structure to implement telecommunication functions or other functions.

[0091] In one embodiment, the control method function of the dual-converter parallel topology structure of the AC power transmission system can be integrated into the central processor 9100. The central processor 9100 can be configured to perform the following control:

[0092] Step S101: performing voltage / frequency control on a first converter so that an output voltage of the first converter is consistent with a target voltage of an AC system.

[0093] Step S102: performing active power / reactive power control on the second converter to optimize the power distribution of the system to a preset state.

[0094] Step S103: coordinately control the first converter and the second converter through a synchronization control unit, and use a parallel inductor to balance the current distribution between the first converter and the second converter, so as to keep the phase synchronization and power quality between the first converter and the second converter stable.

[0095] From the above description, it can be seen that the electronic device provided in the embodiment of the present application significantly improves the transmission capacity of the converter station in the transmission scenario after large-capacity new energy is collected.

[0096] In another embodiment, the control device of the dual-converter parallel topology structure of the AC transmission system can be configured separately from the central processor 9100. For example, the control device of the dual-converter parallel topology structure of the AC transmission system can be configured as a chip connected to the central processor 9100, and the control method function of the dual-converter parallel topology structure of the AC transmission system is implemented through the control of the central processor.

[0097] like Figure 5 As shown, the electronic device 9600 may also include: a communication module 9110, an input unit 9120, an audio processor 9130, a display 9160, and a power supply 9170. It is worth noting that the electronic device 9600 does not necessarily have to include Figure 5 In addition, the electronic device 9600 may also include Figure 5 For components not shown, reference may be made to the prior art.

[0098] like Figure 5 As shown, the central processing unit 9100 is sometimes also referred to as a controller or an operation control, and may include a microprocessor or other processor device and / or logic device. The central processing unit 9100 receives input and controls the operation of various components of the electronic device 9600.

[0099] The memory 9140 may be, for example, one or more of a cache, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory or other suitable devices. The above-mentioned information related to the failure may be stored, and a program for executing the relevant information may also be stored. The CPU 9100 may execute the program stored in the memory 9140 to implement information storage or processing, etc.

[0100] The input unit 9120 provides input to the central processing unit 9100. The input unit 9120 is, for example, a key or a touch input device. The power supply 9170 is used to provide power to the electronic device 9600. The display 9160 is used to display display objects such as images and texts. The display may be, for example, an LCD display, but is not limited thereto.

[0101] The memory 9140 may be a solid-state memory, such as a read-only memory (ROM), a random access memory (RAM), a SIM card, etc. It may also be a memory that saves information even when the power is off, can be selectively erased, and is provided with more data, examples of which are sometimes referred to as EPROMs, etc. The memory 9140 may also be some other type of device. The memory 9140 includes a buffer memory 9141 (sometimes referred to as a buffer). The memory 9140 may include an application / function storage unit 9142, which is used to store application programs and function programs or processes for executing the operation of the electronic device 9600 through the central processor 9100.

[0102] The memory 9140 may also include a data storage unit 9143 for storing data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit 9144 of the memory 9140 may include various drivers for communication functions of the electronic device and / or for executing other functions of the electronic device (such as messaging applications, address book applications, etc.).

[0103] The communication module 9110 is a transmitter / receiver that sends and receives signals via the antenna 9111. The communication module (transmitter / receiver) 9110 is coupled to the central processor 9100 to provide input signals and receive output signals, which may be the same as the case of a conventional mobile communication terminal.

[0104] Based on different communication technologies, multiple communication modules 9110 may be provided in the same electronic device, such as a cellular network module, a Bluetooth module and / or a wireless LAN module, etc. The communication module (transmitter / receiver) 9110 is also coupled to a speaker 9131 and a microphone 9132 via an audio processor 9130 to provide an audio output via the speaker 9131 and receive an audio input from the microphone 9132, thereby realizing a common telecommunication function. The audio processor 9130 may include any suitable buffer, decoder, amplifier, etc. In addition, the audio processor 9130 is also coupled to the central processor 9100, so that recording can be performed on the local machine through the microphone 9132, and the sound stored on the local machine can be played through the speaker 9131.

[0105] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all steps of the control method of the dual-converter parallel topology structure of the AC power transmission system in the above embodiment, where the execution subject is a server or a client. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, all steps of the control method of the dual-converter parallel topology structure of the AC power transmission system in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0106] Step S101: performing voltage / frequency control on a first converter so that an output voltage of the first converter is consistent with a target voltage of an AC system.

[0107] Step S102: performing active power / reactive power control on the second converter to optimize the power distribution of the system to a preset state.

[0108] Step S103: coordinately control the first converter and the second converter through a synchronization control unit, and use a parallel inductor to balance the current distribution between the first converter and the second converter, so as to keep the phase synchronization and power quality between the first converter and the second converter stable.

[0109] From the above description, it can be seen that the computer-readable storage medium provided in the embodiment of the present application significantly improves the transmission capacity of the converter station in the transmission scenario after large-capacity new energy is collected.

[0110] The embodiments of the present application also provide a computer program product capable of implementing all steps of the control method of the dual-converter parallel topology structure of the AC power transmission system in the above-mentioned embodiment, where the execution subject is a server or a client. When the computer program / instruction is executed by a processor, the steps of the control method of the dual-converter parallel topology structure of the AC power transmission system are implemented. For example, the computer program / instruction implements the following steps:

[0111] Step S101: performing voltage / frequency control on a first converter so that an output voltage of the first converter is consistent with a target voltage of an AC system.

[0112] Step S102: performing active power / reactive power control on the second converter to optimize the power distribution of the system to a preset state.

[0113] Step S103: coordinately control the first converter and the second converter through a synchronization control unit, and use a parallel inductor to balance the current distribution between the first converter and the second converter, so as to keep the phase synchronization and power quality between the first converter and the second converter stable.

[0114] From the above description, it can be seen that the computer program product provided in the embodiment of the present application significantly improves the transmission capacity of the converter station in the transmission scenario after large-capacity new energy is collected.

[0115] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0116] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (apparatus), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0117] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0118] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0119] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A dual-converter parallel topology structure of an AC power transmission system, characterized in that: include: A first converter, a second converter and a power transmission control unit; The first converter is used to control the voltage and frequency of the AC power transmission system, the second converter is used to control the active power and reactive power of the AC power transmission system, and the power transmission control unit is used to control and manage the first converter and the second converter; The first converter and the second converter are both capable of controlling the mutual conversion of three-phase electric energy of a first frequency and three-phase electric energy of a second frequency, wherein the first frequency is greater than the second frequency; The first converter and the second converter are connected in three-phase parallel on the same side; One end of the first converter and the second converter connected in parallel is connected to the first AC system, and the other end is connected to the second AC system.

2. The dual converter parallel topology structure according to claim 1, characterized in that: The parallel connection of the first converter and the second converter includes using a parallel reactor to balance current distribution.

3. The dual converter parallel topology structure according to claim 2, characterized in that: The first converter and the second converter work in coordination through a synchronization control unit to achieve phase synchronization and power quality between different frequencies.

4. The dual converter parallel topology structure according to claim 3, characterized in that: The synchronization control unit comprises: A voltage synchronization controller, used to synchronize the output voltage of the first converter with the voltage of the second AC system; A power controller is used to adjust the active power and reactive power output of the second converter.

5. The dual converter parallel topology structure according to any one of claims 1 to 4, characterized in that: The input sides of the first converter and the second converter are both connected to a common DC bus for centralized power supply.

6. The dual converter parallel topology structure according to claim 5, characterized in that: The common DC bus includes a filtering device for suppressing current pulsation to reduce voltage fluctuations and improve system stability.

7. A control method for a dual-converter parallel topology structure of an AC power transmission system, characterized in that: A power transmission control unit of a dual-converter parallel topology structure applied to an AC power transmission system according to claim 3, comprising: Performing voltage / frequency control on the first converter so that the output voltage of the first converter is consistent with the target voltage of the AC system; Performing active power / reactive power control on the second converter so as to optimize the power distribution of the system to a preset state; The first converter and the second converter are coordinated and controlled by a synchronous control unit, and a parallel reactor is used to balance the current distribution of the first converter and the second converter, so that the phase synchronization and power quality between the first converter and the second converter remain stable.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the control method of the dual-converter parallel topology structure of the AC power transmission system described in claim 7 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the control method of the dual-converter parallel topology structure of the AC power transmission system described in claim 7 are implemented.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the control method of the dual-converter parallel topology structure of the AC power transmission system described in claim 7 are implemented.

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