Self-adaptive net following-net construction hybrid synchronization device

Abstract

The utility model discloses a self-adaptive network following-constructing hybrid synchronizer. The device comprises a signal acquisition module, a human-computer interface, a memory, a processor and a digital communication interface, the signal acquisition module is used for acquiring a grid-connected point three-phase voltage signal, a three-phase current signal and a direct-current bus voltage signal, and sending the signals to the processor through the digital communication interface; the human-computer interface is used for inputting a plurality of oscillation voltage fixed values and a plurality of oscillation current fixed values and sending the oscillation voltage fixed values and the oscillation current fixed values to the processor through the digital communication interface, and the processor sends the received oscillation voltage fixed values and the oscillation current fixed values to the memory for storage; the processor is used for obtaining the hybrid synchronization reference phase and outputting the hybrid synchronization reference phase. By utilizing the scheme of the utility model, the self-adaptive mixing of a network following synchronization mode and a network construction synchronization mode can be realized, so that the converter has good oscillation stability under different power grid conditions.

Description

Technical Field

[0001] This utility model generally relates to the field of power system analysis and control technology. More specifically, this utility model relates to an adaptive grid-connection hybrid synchronization device. Background Technology

[0002] In existing technologies, wind power, photovoltaic power, and other new energy sources are connected to the power grid via power electronic converters. The grid synchronization methods for these converters include grid-following synchronization (also known as phase-locked loop synchronization) and grid-connected synchronization. Converters using grid-following synchronization possess active support capabilities for frequency and voltage in strong power grids, exhibiting good strong power grid oscillation characteristics and improving power grid frequency and voltage stability. Converters using grid-connected synchronization possess active support capabilities for frequency and voltage in weak power grids, exhibiting good weak power grid oscillation characteristics and improving power grid frequency and voltage stability.

[0003] However, converters using grid synchronization are at risk of oscillation and instability in weak power grids. Converters using grid-connected synchronization are at risk of oscillation and instability in strong power grids, and multiple converters using grid-connected synchronization operate in parallel, also at risk of oscillation and instability.

[0004] In view of this, there is an urgent need to provide an adaptive grid-following and grid-building hybrid synchronization scheme, which combines the advantages of the converter adopting grid-following and grid-building synchronization methods respectively, so that the converter has good oscillation stability under different grid conditions. Utility Model Content

[0005] In order to solve at least one or more of the technical problems mentioned above, this utility model proposes an inertial flywheel control scheme based on reinforcement learning in several aspects.

[0006] In a first aspect, this utility model provides an adaptive grid-connection hybrid synchronization device, comprising: a signal acquisition module, a human-machine interface, a memory, a processor, and a digital communication interface; the signal acquisition module is used to acquire three-phase voltage signals, three-phase current signals, and DC bus voltage signals at the grid connection point, and transmit them to the processor through the digital communication interface; the human-machine interface is used to input multiple oscillation voltage setpoints and multiple oscillation current setpoints, and transmit them to the processor through the digital communication interface; the processor sends the received multiple oscillation voltage setpoints and multiple oscillation current setpoints to the memory for storage; the processor is used to sequentially acquire the grid connection reference frequency, the phase-locked loop reference frequency, the oscillation component amplitude of the three-phase voltage signal at the grid connection point, the oscillation component amplitude of the three-phase current signal at the grid connection point, the phase-locked loop coefficient, and the hybrid synchronization reference phase, and output the hybrid synchronization reference phase.

[0007] In some embodiments, the signal acquisition module includes a voltage transformer, a current transformer, and a DC voltage sensor.

[0008] In some embodiments, the signal acquisition module further includes an operational amplifier and an analog-to-digital converter. The operational amplifier is connected to the voltage transformer, the current transformer, and the DC voltage sensor, respectively, and the analog-to-digital converter is connected to the operational amplifier.

[0009] In some embodiments, the human-machine interface includes a display screen and buttons.

[0010] In some embodiments, the memory is a read-only memory or a random access memory.

[0011] In some embodiments, the processor is a microcontroller or a digital signal processor.

[0012] In some embodiments, the digital communication interface adopts an SPI interface, I... 2 C interface or UART interface.

[0013] In some embodiments, the adaptive tracking-networking hybrid synchronization device further includes a host computer and a serial communication interface, wherein the host computer communicates with the processor via serial communication.

[0014] By using the adaptive grid-connection hybrid synchronization device provided above, this embodiment of the invention obtains a hybrid synchronization reference phase by using the three-phase voltage signal, three-phase current signal, and DC bus voltage signal acquired by the signal acquisition module at the grid connection point, as well as multiple oscillation voltage settings and multiple oscillation current settings input by the human-machine interface as inputs to the processor. This enables the adaptive hybridization of grid-connection synchronization and grid-connection synchronization, resulting in good oscillation stability of the converter under different grid conditions. Attached Figure Description

[0015] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0016] Figure 1 This diagram illustrates the composition of an adaptive tracking network-network hybrid synchronization device according to some embodiments of the present invention;

[0017] Figure 2 A schematic diagram of the composition of an adaptive tracking network-network hybrid synchronization device according to other embodiments of the present invention is shown;

[0018] Figure 3 A schematic diagram of the signal acquisition module according to an embodiment of the present invention is shown;

[0019] Figure 4 A schematic diagram of the processor composition according to an embodiment of the present invention is shown. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0021] It should be understood that the terms "comprising" and "including" used in the specification and claims of this utility model indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0022] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0023] As used in this specification and claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0024] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0025] This utility model provides an adaptive grid-following and grid-building hybrid synchronization scheme, which can achieve an adaptive hybrid of grid-following and grid-building synchronization methods, so that the converter has good oscillation stability under different grid conditions.

[0026] Figure 1 An exemplary flowchart of an adaptive tracking network-network hybrid synchronization device 100 according to some embodiments of the present invention is shown.

[0027] like Figure 1 As shown, the adaptive tracking network-network hybrid synchronization device 100 includes a signal acquisition module 110, a human-machine interface 120, a memory 130, a processor 140, and a digital communication interface 150. Both human-machine interfaces 120 and processor 140 communicate with each other through the digital communication interface 150. The memory 130 is connected to the processor 140.

[0028] Specifically, the signal acquisition module 110 is used to acquire the three-phase voltage signal, three-phase current signal, and DC bus voltage signal at the grid connection point, and send them to the processor 140 through a digital communication interface. The human-machine interface 120 is used to input multiple oscillation voltage settings and multiple oscillation current settings, and send them to the processor 140 through a digital communication interface 150. The processor 140 sends the received multiple oscillation voltage settings and multiple oscillation current settings to the memory 130 for storage. The processor 140 is used to sequentially acquire the grid reference frequency, the phase-locked loop reference frequency, the oscillation component amplitude of the three-phase voltage signal at the grid connection point, the oscillation component amplitude of the three-phase current signal at the grid connection point, the phase-locked loop coefficient, and the hybrid synchronization reference phase, and output the hybrid synchronization reference phase.

[0029] Specifically, the hybrid synchronous reference phase can be output to the human-machine interface 120 for display.

[0030] In other embodiments of this utility model, the aforementioned device 100 may further include a host computer and a serial communication interface. The following is in conjunction with... Figure 2 The specific composition of the aforementioned device 100 in other embodiments is described.

[0031] Figure 2 A schematic diagram of the composition of an adaptive tracking network-network hybrid synchronization device 100 according to other embodiments of the present invention is shown.

[0032] like Figure 2 As shown, the aforementioned device 100 includes, in addition to the aforementioned signal acquisition module 110, human-machine interface 120, memory 130, processor 140, and digital communication interface 150, a host computer 160 and a serial communication interface 170. Specifically, the host computer 160 communicates with the aforementioned processor 140 through the serial communication interface 170.

[0033] Specifically, the host computer 160 can be used to receive and display the hybrid synchronization reference phase sent by the processor 140. The host computer 160 can also be used to receive multiple oscillation voltage settings and multiple oscillation current settings input by the user, and send them to the processor 140 through the serial communication interface 170. The processor 140 will then send the received multiple oscillation voltage settings and multiple oscillation current settings to the memory 130 for storage.

[0034] In embodiments of this utility model, the exemplary specific composition of the aforementioned signal acquisition module 110 can be found in [reference needed]. Figure 3 . Figure 3 A schematic diagram of the signal acquisition module according to an embodiment of the present invention is shown. Figure 3 As shown, the signal acquisition module 110 includes a voltage transformer 111, a current transformer 112, a DC voltage sensor 113, an operational amplifier 114, and an analog-to-digital converter 115. The operational amplifier 114 is connected to the voltage transformer 111, the current transformer 112, and the DC voltage sensor 113, respectively, and the analog-to-digital converter 115 is connected to the operational amplifier 114.

[0035] In this embodiment of the invention, a voltage transformer 111 acquires the three-phase voltage signal at the grid connection point, a current transformer 112 acquires the three-phase current signal at the grid connection point, and a DC voltage sensor 113 acquires the DC bus voltage signal. Then, an operational amplifier 114 amplifies the three-phase voltage signal, current signal, and DC bus voltage signal acquired by the voltage transformer 111, the current transformer 112, and the DC voltage sensor 113. Next, an analog-to-digital converter 115 converts the amplified analog signal into a digital signal and sends it to the processor 140 via a digital communication interface 150.

[0036] In the embodiments of this utility model, the voltage transformer 111, the current transformer 112, the DC voltage sensor 113, the operational amplifier 114, and the analog-to-digital converter 115 can all be electronic devices or electronic components in the prior art, and this utility model does not impose any limitations on them.

[0037] In embodiments of this invention, the human-machine interface 120 may include a display screen and buttons. Specifically, the display screen may be a touch screen or a non-touch screen. When the display screen is a touch screen, the aforementioned buttons may include function buttons and numeric buttons, or only function buttons. When the display screen is a non-touch screen, the aforementioned buttons include function buttons and numeric buttons.

[0038] Specifically, the aforementioned function keys may include power buttons, confirmation buttons, delete buttons, cancel buttons, etc. When the display screen is a touch screen, the function keys may include only power buttons, or they may include power buttons and one or more of the other categories of function keys listed above. When the display screen is a non-touch screen, the function keys include all categories of function keys listed above.

[0039] In embodiments of this utility model, users can input multiple oscillation voltage settings and multiple oscillation current settings through the human-machine interface 120 or the host computer 160, which allows users to flexibly select the human-machine interface or the host computer as needed.

[0040] In some embodiments of this utility model, the user can input the first oscillation voltage setpoint A through the human-machine interface 120 or the host computer 160. u1 Second oscillation voltage setting A u2 First oscillation current setting A i1 Second oscillation current setting A i2 .

[0041] When the user inputs multiple oscillation voltage and multiple oscillation current settings through the human-machine interface 120, the multiple oscillation voltage and multiple oscillation current settings are sent to the processor 140 through the digital communication interface 150. The processor 140 then sends the received multiple oscillation voltage and multiple oscillation current settings to the memory 130 for storage.

[0042] When the user inputs multiple oscillation voltage and multiple oscillation current settings through the host computer 160, the multiple oscillation voltage and multiple oscillation current settings are sent to the processor 140 through the serial communication interface 170. The processor 140 then sends the received multiple oscillation voltage and multiple oscillation current settings to the memory 130 for storage.

[0043] In embodiments of this utility model, multiple oscillation voltage and current settings can be set instantly via the human-machine interface 120 or the host computer 160, and the processor 140 processes the received multiple oscillation voltage and current settings in real time. Alternatively, multiple oscillation voltage and current settings can be pre-input via the human-machine interface 120 or the host computer 160, and the processor 140 sends the received multiple oscillation voltage and current settings to the memory 130 for storage. When the processor 140 needs to process the multiple oscillation voltage and current settings, it retrieves them from the memory 130.

[0044] In embodiments of this invention, the aforementioned memory 130 may be a read-only memory or a random access memory. Specifically, the read-only memory may include electrically erasable programmable read-only memory (EEPROM), and the random access memory may include phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), etc. The aforementioned memory 130 may also be selected from other types of memory according to the application scenario and actual needs, and this invention does not impose any limitations.

[0045] The memory 130 can be used to store multiple oscillation voltage settings and multiple oscillation current settings for the processor 140 to recall. The memory 130 can also be used to store algorithms for the processor 140 to recall in order to implement corresponding functions.

[0046] In the embodiments of this utility model, the aforementioned digital communication interface 150 is used to realize communication between the signal acquisition module 110 and the processor 140, and between the human-machine interface 120 and the processor 140. It can adopt an SPI interface, an I2C interface, or a UART interface. The aforementioned digital communication interface 150 can also be selected with other types of interfaces according to the application scenario and actual needs, and this utility model does not impose any restrictions.

[0047] In embodiments of this utility model, the aforementioned host computer 160 can be a computer, mobile terminal, or the like. The host computer 160 can also be selected from other devices depending on the application scenario and actual needs; this utility model does not impose any limitations on this.

[0048] In the embodiments of this utility model, the aforementioned serial communication interface 170 is used to realize communication between the host computer 160 and the processor 140, and it can adopt an RJ45 port, RS485 interface, RS232 interface or USB interface. The aforementioned serial communication interface 170 can also be selected with other interfaces according to the application scenario and actual needs, and this utility model does not impose any restrictions.

[0049] In embodiments of this invention, the aforementioned processor 140 may be a microcontroller or a digital signal processor. The processor 140 may also be selected from other types of control units depending on the application scenario and actual needs; this invention does not impose any limitations on these selections.

[0050] In an embodiment of this utility model, the processor 140 calls the algorithm stored in the memory 130 to obtain the grid reference frequency, the phase-locked loop reference frequency, the amplitude of the oscillation component of the three-phase voltage signal at the grid connection point, the amplitude of the oscillation component of the three-phase current signal at the grid connection point, the phase-locked loop coefficient, and the hybrid synchronization reference phase. The following is in conjunction with... Figure 4 The corresponding virtual units of processor 140 are described.

[0051] Figure 4 A schematic diagram of the processor composition according to an embodiment of the present invention is shown.

[0052] like Figure 4As shown, the processor 140 includes a power calculation module 141, an oscillation monitoring module 142, a network synchronization module 143, a phase-locked loop (PLL) synchronization module 144, a PLL coefficient calculation module 145, and a hybrid synchronization module 146. Specifically, the hybrid synchronization module 146, in addition to outputting the acquired hybrid synchronization reference phase θ to the human-machine interface 120 or the host computer 160, also outputs the acquired hybrid synchronization reference phase θ to the signal acquisition module 110.

[0053] In an embodiment of this utility model, the power calculation module 141 is used to calculate the three-phase voltage signal u at the grid connection point obtained from the signal acquisition module 110. abc and the three-phase current signal i at the grid connection point abc Obtain the active power P output at the grid connection point.

[0054] In this embodiment of the invention, the oscillation monitoring module 142 is used to monitor the first oscillation voltage setpoint A input by the user through the human-machine interface 120 or the host computer 160. u1 Second oscillation current setting A i2 Calculate the three-phase voltage signal u at the grid connection point abc and the three-phase current signal i at the grid connection point abc The amplitude of the oscillation component, i.e., solving for the three-phase voltage signal u at the grid connection point. abc and the three-phase current signal i at the grid connection point abc Amplitude at frequencies other than the power frequency (e.g., 50Hz).

[0055] Specifically, when the voltage amplitude at a certain frequency is higher than A u1 Or the current amplitude is higher than A i1 When this happens, the output oscillation voltage amplitude A u,m Output oscillation current amplitude A i,m (m=1,2,…,n), where m represents the m-th oscillation component and n represents the total number of oscillation voltages / currents; otherwise, the output A u,1 =0, A i,1 =0.

[0056] In this embodiment of the invention, the network synchronization module 143 generates a network reference frequency Δω based on the DC bus voltage signal acquired by the signal acquisition module 110 or the active power P output by the power calculation module 141. Specifically, the generation of the network reference frequency Δω based on the output active power P can be achieved through existing active power synchronization mechanisms, such as droop control and virtual synchronization control, which are not limited in this invention. The generation of the network reference frequency Δω based on the DC bus voltage signal acquired by the signal acquisition module 110 can be achieved through a DC bus voltage synchronization mechanism, also known as matching control, which is not limited in this invention.

[0057] In an embodiment of this utility model, the three-phase voltage signal u at the grid connection point acquired by the signal acquisition module 110 is... abc Three-phase current signal at grid connection point iabc The hybrid synchronization module 146 currently outputs the hybrid synchronization reference phase θ, which is then input to the Parker transform stage to obtain the d-axis component u of the three-phase voltage at the grid connection point. d and q-axis component u q The phase-locked loop synchronization module 144 is used to synchronize the q-axis component u of the three-phase voltage at the grid connection point. q The input is fed into the PI control loop to obtain the phase-locked loop reference frequency Δω. PLL .

[0058] In this embodiment of the invention, the phase-locked loop coefficient calculation module 145 is used to calculate the sum A of the oscillation voltage amplitudes output by the oscillation monitoring module 142. u,sum And the sum of the amplitudes of the oscillating currents, A i,sum Then, the sum of the oscillation voltage amplitudes A was compared. u,sum The second oscillation voltage setting A can be input by the user through the human-machine interface 120 or the host computer 160. u2 The sum of the amplitudes of the oscillating currents A i,sum The second oscillation current setting A can be input by the user through the human-machine interface 120 or the host computer 160. i2 The phase-locked loop coefficient K is adaptively adjusted.

[0059] Specifically, when A u,sum u2 And A i,sum i2 When the condition is met, set the output K to 0; otherwise, set K to a positive number, and A... u,sum and A i,sum The larger the value, the larger K becomes. In the embodiments of this utility model, the adjustment range of the phase-locked loop coefficient K needs to be determined based on the converter control structure, control parameters, and the grid conditions. This utility model does not impose any limitations on this.

[0060] In this embodiment of the invention, the hybrid synchronization module 146 adaptively adjusts the converter-grid synchronization mode according to the system oscillation, specifically by calculating the hybrid synchronization reference phase θ using the following formula:

[0061] Where, ω ref Here, s is the set reference angular frequency, Δω is the Laplace operator, Δω is the network reference frequency output by the network synchronization module 143, ΔωPLL is the phase-locked loop reference frequency output by the phase-locked loop synchronization module 144, and K is the phase-locked loop coefficient output by the phase-locked loop coefficient calculation module 145.

[0062] ​​In summary, through the solution provided above, this utility model embodiment obtains a hybrid synchronization reference phase by using the three-phase voltage signal, three-phase current signal, and DC bus voltage signal acquired by the signal acquisition module, as well as multiple oscillation voltage settings and multiple oscillation current settings input by the human-machine interface, and achieves an adaptive hybrid of grid-connected synchronization mode and grid-connected synchronization mode, so that the converter has good oscillation stability under different grid conditions.

[0063] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of the present invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in the practice of the present invention. The appended claims are intended to define the scope of protection of the present invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. An adaptive tracking-network hybrid synchronization device, characterized in that, include: Signal acquisition module, human-machine interface, memory, processor, and digital communication interface; The signal acquisition module is used to acquire the three-phase voltage signal, three-phase current signal and DC bus voltage signal at the grid connection point, and send them to the processor through the digital communication interface; The human-machine interface is used to input multiple oscillation voltage setpoints and multiple oscillation current setpoints, and send them to the processor through a digital communication interface. The processor will send the received multiple oscillation voltage setpoints and multiple oscillation current setpoints to the memory for storage. The processor is used to sequentially acquire the grid reference frequency, the phase-locked loop reference frequency, the amplitude of the oscillation component of the three-phase voltage signal at the grid connection point, the amplitude of the oscillation component of the three-phase current signal at the grid connection point, the phase-locked loop coefficient, and the hybrid synchronization reference phase, and output the hybrid synchronization reference phase.

2. The adaptive tracking-network-network hybrid synchronization device according to claim 1, characterized in that, The signal acquisition module includes a voltage transformer, a current transformer, and a DC voltage sensor.

3. The adaptive tracking-network-network hybrid synchronization device according to claim 2, characterized in that, The signal acquisition module further includes an operational amplifier and an analog-to-digital converter. The operational amplifier is connected to the voltage transformer, the current transformer and the DC voltage sensor respectively, and the analog-to-digital converter is connected to the operational amplifier.

4. The adaptive tracking-network-network hybrid synchronization device according to claim 1, characterized in that, The human-machine interface includes a display screen and buttons.

5. The adaptive tracking-network-network hybrid synchronization device according to claim 1, characterized in that, The memory may be a read-only memory or a random access memory.

6. The adaptive tracking-network-network hybrid synchronization device according to claim 1, characterized in that, The processor is a microcontroller or a digital signal processor.

7. The adaptive tracking-network-network hybrid synchronization device according to claim 1, characterized in that, The digital communication interface adopts an SPI interface and an I interface. 2 C interface or UART interface.

8. The adaptive tracking-network-network hybrid synchronization device according to claim 1, characterized in that, It also includes a host computer and a serial communication interface, wherein the host computer communicates with the processor via serial communication.

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