Universal inverter copying and reading method based on distributed power supply access unit

Abstract

The invention relates to the technical field of photovoltaic data acquisition, in particular to a general inverter reading method based on a distributed power supply access unit. The method is used for converting the standard format data interaction message issued by the acquisition terminal into the MODBUS protocol supported by the photovoltaic inverter through the distributed power supply access unit. The method comprises the following steps: S1, carrying out address self-adaption on a distributed power supply access unit and a photovoltaic inverter; and S2, protocol self-adaption is carried out on the distributed power supply access unit and the photovoltaic inverter. Aiming at the problems of low address self-adaption efficiency and long consumed time in the existing method, the address field is divided into the high-priority block and the low-priority block, and detection is performed according to the priority sequence, so that the long consumed time caused by traversing according to the address field sequence is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic data acquisition, and more specifically, to a general reading method for inverters based on a distributed power supply access unit. Background Art

[0002] With the development of photovoltaic technology, more and more photovoltaic inverters are involved in photovoltaic power generation and feed power into the grid. To ensure the sustainable development of distributed photovoltaic power generation technology, promote the utilization of new energy while ensuring the safety and power supply reliability of the grid, it is necessary to strengthen the monitoring and control of distributed power supply access.

[0003] The distributed power supply access unit, as the currently promoted monitoring device, has functions such as communication protocol conversion, data acquisition, power quality monitoring, remote / local control, etc., and supports the acquisition terminal to monitor the photovoltaic inverter through it.

[0004] However, photovoltaic inverters from different manufacturers have one or even multiple sets of custom MODBUS protocols, resulting in the inability to monitor photovoltaic inverters from different manufacturers through a unified command. The Chinese invention patent with the patent number 202310359457.0 discloses a protocol adaptation method between a photovoltaic protocol converter and a photovoltaic inverter. Its technical solution includes the following steps: the converter sends address adaptation messages with different address domains to the inverter; the inverter replies after receiving the message; if the reply from the inverter is received, the converter determines that this address is the inverter address; the converter sends a protocol adaptation message with the above address as the address domain, that is, a custom protocol, to the inverter; if the content of the inverter register matches the content of the register in the received message, it is determined that this message is the protocol supported by the inverter, and the inverter replies to the converter to complete the protocol adaptation; otherwise, the converter continues to send a new custom protocol to the inverter until the protocol adaptation is completed. However, it is found in the use of this method that the step of address adaptation has low efficiency and results in a long time-consuming address adaptation. Summary of the Invention

[0005] Based on this, in view of the problems of low efficiency and long time consumption of address adaptation in the existing method, it is necessary to provide a general reading method for inverters based on a distributed power supply access unit.

[0006] The present invention is implemented by the following technical solutions:

[0007] In a first aspect, the present invention discloses a general reading method for inverters based on a distributed power supply access unit, which is used to convert the standard format data interaction message sent by the acquisition terminal into the MODBUS protocol supported by the photovoltaic inverter through the distributed power supply access unit.

[0008] The general reading method for inverters based on a distributed power access unit includes the following steps:

[0009] S1. The distributed power access unit performs address self - adaptation with the photovoltaic inverter.

[0010] Among them, S1 includes:

[0011] S101. The distributed power access unit divides the address domain from 1 to 247 into high - priority blocks and low - priority blocks.

[0012] S102. The distributed power access unit probes the high - priority blocks.

[0013] If the probe is successful, lock the corresponding address as the photovoltaic inverter address and perform S2.

[0014] If traversing the high - priority blocks and the probe is not successful, perform S103.

[0015] S103. The distributed power access unit probes the low - priority blocks.

[0016] If the probe is successful, lock the corresponding address as the photovoltaic inverter address and perform S2.

[0017] If traversing the low - priority blocks and the probe is not successful, end.

[0018] S2. The distributed power access unit performs protocol self - adaptation with the photovoltaic inverter.

[0019] The general reading method for inverters based on a distributed power access unit implements the method or process according to the embodiments of the present disclosure.

[0020] In a second aspect, the present invention discloses a distributed power access unit, which adopts the general reading method for inverters based on a distributed power access unit as disclosed in the first aspect.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. Aiming at the problems of low address self - adaptation efficiency and long time consumption in the existing method, the present invention divides the address domain into high - priority blocks and low - priority blocks, and probes according to the priority order, shortening the long time consumption caused by traversing in the order of the address domain.

[0023] 2. The present invention adopts a sub - block division method for high - priority blocks, and uses time - division multiplexing technology to probe the addresses in each high - priority sub - block in parallel, effectively shortening the overall probing time for high - priority blocks.

[0024] 3. The present invention provides two types of solutions for low-priority blocks, with high flexibility: Solution 1 adopts the method of sub-block division, and parallel detection is carried out on the addresses within each low-priority sub-block by using time-division multiplexing technology, effectively shortening the overall detection time for low-priority blocks; Solution 2 is based on the method of jump detection to reduce the number of detections.

[0025] 4. The present invention also provides a dynamic update method for high-priority blocks and low-priority blocks, enabling them to increase the address hit rate based on historical data. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is the topological connection diagram of the acquisition terminal, distributed power access unit, and photovoltaic inverter proposed in Embodiment 1 of the present invention;

[0028] Figure 2 It is the flowchart of the inverter general reading method based on the distributed power access unit provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0030] It should be noted that when a component is referred to as "installed on" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "set on" another component, it can be directly set on the other component or there may be an intermediate component at the same time. When a component is considered to be "fixed to" another component, it can be directly fixed to the other component or there may be an intermediate component at the same time.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used in the description of this invention herein are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0032] Embodiment

[0033] First of all, it should be noted that this invention is an improvement on an existing patent (a Chinese invention patent with the patent number 202310359457.0, a protocol adaptation method between a photovoltaic protocol converter and a photovoltaic inverter).

[0034] Specifically, referring to Figure 1 , this invention uses a distributed power access unit to convert the standard format data interaction message sent by the acquisition terminal into the MODBUS protocol supported by the photovoltaic inverter. That is to say, this invention replaces the photovoltaic protocol converter in the existing patent with a distributed power access unit.

[0035] Among them, it is recommended that the acquisition terminal and the distributed power access unit be communicatively connected by RS485 or HPLC; it is recommended that the photovoltaic inverter and the distributed power access unit be communicatively connected by RS485.

[0036] Referring to Figure 2 , this invention also provides a general inverter reading method based on the distributed power access unit - that is, the distributed power access unit can use this method to achieve the above functions.

[0037] As Figure 2 shown, a general inverter reading method based on the distributed power access unit includes:

[0038] S1, the distributed power access unit adapts the address with the photovoltaic inverter;

[0039] S2, the distributed power access unit adapts the protocol with the photovoltaic inverter.

[0040] It should be noted that this invention only improves the address adaptation compared with the existing patent and does not modify the protocol adaptation (only replaces the photovoltaic protocol converter in the existing patent with a distributed power access unit). Therefore, S2 will not be elaborated here.

[0041] For the address adaptation of existing patents, the traditional polling method is adopted: sending a message to address 1 → waiting for a response (such as 50 ms) → no response → sending a message to address 2 → waiting for a response (such as 50 ms) →..., then it takes at least 247×50 ms = 12.35 seconds to traverse from 1 to 247. It can be seen that most of the time is wasted on waiting for the timeout of unresponsive addresses.

[0042] The following details S1 of this method, which includes:

[0043] S101, the distributed power access unit divides the address domain from 1 to 247 into high-priority blocks and low-priority blocks.

[0044] The high-priority blocks and low-priority blocks are divided according to the probability distribution of address detection and the requirements of efficiency optimization to achieve the goal of quickly locating the effective inverter address.

[0045] That is to say, the high-priority block is the address range where there is a high probability of an effective inverter address - it can be the manufacturer's default address or the user-specified address.

[0046] The low-priority block is the address range where there is a low probability of an effective inverter address, that is, the part of the address domain except the initial value of the high-priority block.

[0047] It should be noted that the high-priority blocks and low-priority blocks can remain unchanged all the time; it can also be designed to dynamically update the high-priority blocks and low-priority blocks based on the historical data of address adaptation - specifically, the methods for dynamic update include:

[0048] Obtain the historical data of address adaptation within a preset period (generally designed to look back a period of time T from the current moment, and the value of T can be adjusted according to the actual situation), and count the number of times each address is successfully detected;

[0049] Add the addresses with the number of successful detections greater than a preset threshold one to the high-priority block;

[0050] Add the addresses with the number of successful detections less than a preset threshold two to the low-priority block;

[0051] The remaining addresses remain unchanged; among them, the preset threshold two is less than the preset threshold one.

[0052] It should be noted that the values of the preset threshold two and the preset threshold one can be adjusted according to the actual situation.

[0053] In addition, the initial value of the high-priority block is the manufacturer's default address or the user-specified address, and the initial value of the low-priority block is the part of the address domain except the initial value of the high-priority block.

[0054] S102, the distributed power access unit detects the high-priority block;

[0055] If the detection is successful, lock the corresponding address as the PV inverter address and perform S2;

[0056] If the traversal of the high-priority block and the detection are both unsuccessful, perform S103.

[0057] Based on the division of S1, the high-priority block should be detected preferentially. However, if the traversal is still carried out in the order of the address domain, it still takes a long time; therefore, S102 is recommended to adopt the following method:

[0058] Divide the high-priority block into multiple high-priority sub-blocks, and parallelly detect the addresses within each high-priority sub-block by using the time-division multiplexing technology.

[0059] Among them, the time slot of a single address within a single high-priority sub-block is t 高 ;

[0060] t 高 = t1 ,高 + t2 ,高 ;

[0061] In the formula, t 1,高 represents the time taken for the distributed power access unit to send a message to a single address within a single high-priority sub-block; t 2,高 represents the listening response time of the distributed power access unit to a single address within a single high-priority sub-block.

[0062] It should be noted that RS-485 is a half-duplex communication - only allowing a single device to send data at the same time; then, the time-division multiplexing technology does not send multiple messages simultaneously at the physical layer, but simulates the parallel effect in the time dimension. Specifically, the time-division multiplexing divides time into multiple fixed-length time slots, and only processes the detection task of one address within each time slot and quickly switches the target address between different time slots to reduce the idle waiting time.

[0063] The following is an example for illustration:

[0064] If the high-priority block is [1, 50], then traversing and detecting according to the address domain takes 50 × 50 ms = 2500 ms;

[0065] If according to S1 of this case, it can be divided into 5 high-priority sub-blocks with 10 addresses in a group - [1, 10], [11, 20], [21, 30], [31, 40], [41, 50]. t 高 is designed as 10 ms, t 1,高 is designed as 2 ms, t2,高 It is designed to be 8 ms. Then, start block detection from [1, 10] - send a detection message for address 1 and randomly listen for responses. If a response is received within 8 ms, lock address 1. If no response is received after 8 ms, start sending a detection message for address 2 and randomly listen for responses, and so on until [1, 10] is traversed. If [1, 10] is not hit, jump to [11, 20], and so on until [1, 50] is traversed. Then the total time taken to traverse 5 high - priority sub - blocks is 5×10×10 ms = 500 ms, significantly shortening the duration.

[0066] S103, the distributed power access unit detects the low - priority block;

[0067] If the detection is successful, lock the corresponding address as the PV inverter address and perform S2;

[0068] If traversing the low - priority block and the detection is not successful, end;

[0069] ① The low - priority block can adopt a similar method to the high - priority block:

[0070] Divide the low - priority block into multiple low - priority sub - blocks, and use time - division multiplexing technology to detect the addresses of each low - priority sub - block in parallel;

[0071] Among them, the time slot for a single address within a single low - priority sub - block is t 低 ;

[0072] t 低 =t1 ,低 +t2 ,低 ;

[0073] In the formula, t 1,低 represents the time taken for the distributed power access unit to send a message to a single address within a single low - priority sub - block; t 2,低 represents the time taken for the distributed power access unit to listen for responses to a single address within a single low - priority sub - block.

[0074] The detection principle of the low - priority block is the same as that of the high - priority block, and no specific example will be given here.

[0075] It should be noted that considering the difference in hit rate between the low - priority block and the high - priority block, it is recommended that t 1,低 =t 1,高 ; t 2,高 ≥t 2,低 . Generally, set t 2,高 to be smaller than t 2,低 , so as to achieve a quick skip and further reduce the waiting time.

[0076] In addition, the following settings can be added:

[0077] If there is no response from M consecutive addresses within a certain low-priority sub-block, then skip the subsequent other addresses within this low-priority sub-block and start probing the starting address of the next low-priority sub-block; M represents a preset quantity threshold - its value can be adjusted according to the actual situation. This can accelerate the probing of sub-blocks.

[0078] ② The low-priority block can also adopt a jump-probing method to reduce the number of probes.

[0079] It should be noted that the jump-probing can adopt a fixed step size or a gradually decreasing step size.

[0080] Ⅰ. If the fixed-step-size method is adopted, then S103 is designed as:

[0081] S1031, starting from the first address of the low-priority block, perform jump-probing towards the second address of the low-priority block according to the preset step size step;

[0082] Among them, the first address is initialized as the starting address and the second address is initialized as the ending address;

[0083] S1032, if a certain jump-probing in S1031 is successful, then lock the corresponding address as the PV inverter address and perform S2;

[0084] If all jump-probings in S1031 are unsuccessful, then take the address after the first address as the first address and return to S1031.

[0085] Among them, the value of the preset step size step is selected according to the actual situation, and generally 5 is taken.

[0086] Of course, S103 can also be designed as:

[0087] S1031, starting from the first address of the low-priority block, perform jump-probing towards the second address of the low-priority block according to the preset step size step;

[0088] Among them, the first address is initialized as the ending address and the second address is initialized as the starting address;

[0089] S1032, if a certain jump-probing in S1031 is successful, then lock the corresponding address as the PV inverter address and perform S2;

[0090] If all jump-probings in S1031 are unsuccessful, then take the address before the first address as the first address and return to S1031.

[0091] The difference between the above two methods lies in the detection direction - the former is from the beginning to the end, and the latter is from the end to the beginning.

[0092] II. If the method of gradually reducing the step size is adopted, then S103 is designed as follows:

[0093] Starting from the first address of the low-priority block, according to the preset step size step n Perform the nth round of jump detection towards the second address of the low-priority block; n≥1;

[0094] If a jump detection is successful in the nth round, lock the corresponding address as the photovoltaic inverter address and perform S2;

[0095] If all jump detections in the nth round are unsuccessful, then starting from the first address of the low-priority block, according to the preset step size step n+1 Perform the (n + 1)th jump detection towards the second address of the low-priority block; where 1≤step n+1 <step n ;

[0096] Among them, the first address is initialized to the starting address, and the second address is initialized to the ending address;

[0097] Or, the first address is initialized to the ending address, and the second address is initialized to the starting address.

[0098] It should be noted that step n+1 and step n can be designed to differ by 1, or can be designed to differ by a value greater than 1 to adapt to different situations. For example, step1 can be set to 5, step2 can be set to 4, step3 can be set to 3, step4 can be set to 2, step5 can be set to 1; or, step1 can be set to 5, step2 can be set to 2, step3 can be set to 1.

[0099] In summary, detect the high-priority block and the low-priority block to achieve address self-adaptation, and then normally perform S2.

[0100] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A general reading method for inverters based on distributed power access units, characterized in that, It is used to convert the standard format data interaction message sent by the acquisition terminal into the MODBUS protocol supported by the photovoltaic inverter through the distributed power access unit; The inverter general reading method based on the distributed power access unit includes: S1. The distributed power access unit performs address self - adaptation with the photovoltaic inverter; Among them, S1 includes: S101. The distributed power access unit divides the address domain from 1 to 247 into high - priority blocks and low - priority blocks according to priority; S102. The distributed power access unit probes the high - priority blocks; If the probe is successful, lock the corresponding address as the photovoltaic inverter address and perform S2; If the traversal of the high - priority blocks and the probe are both unsuccessful, then perform S103; S103. The distributed power access unit probes the low - priority blocks; If the probe is successful, lock the corresponding address as the photovoltaic inverter address and perform S2; If the traversal of the low - priority blocks and the probe are both unsuccessful, then end; S2. The distributed power access unit performs protocol self - adaptation with the photovoltaic inverter.

2. The general reading method of the inverter based on the distributed power access unit according to claim 1, characterized in that, In S102, the high - priority block is divided into multiple high - priority sub - blocks, and the addresses within each high - priority sub - block are probed in parallel using time - division multiplexing technology; Among them, the time slot of a single address within a single high-priority sub-block is t 高 ; t 高 = t1 ,高 + t2 ,高 ; where t 1,高 represents the time taken for the distributed power access unit to send a message to a single address within a single high-priority sub-block; t 2,高 represents the listening response time of the distributed power access unit to a single address within a single high-priority sub-block.

3. The general reading method of the inverter based on the distributed power access unit according to claim 2, characterized in that, In S103, the low - priority block is divided into multiple low - priority sub - blocks, and the addresses of each low - priority sub - block are probed in parallel using time - division multiplexing technology; Among them, the time slot of a single address within a single low-priority sub-block is t 低 ; t 低 = t1 ,低 + t2 ,低 ; where t 1,低 represents the time taken for the distributed power access unit to send a message to a single address within a single low-priority sub-block; t 2,低 represents the listening response time of the distributed power access unit to a single address within a single low-priority sub-block.

4. The inverter general reading method based on a distributed power access unit according to claim 3, wherein t 1,低 = t 1,高 ; t 2,高 ≥ t 2,低 ; Or / and, the number of addresses in a single high - priority sub - block is less than the number of addresses in a single low - priority sub - block.

5. The inverter general reading method based on the distributed power access unit according to claim 3, characterized in that, In S103, if there is no response for M consecutive addresses within a certain low - priority sub - block, skip the subsequent other addresses within this low - priority sub - block and start probing from the start address of the next low - priority sub - block; M represents a preset quantity threshold.

6. The general reading method of the inverter based on the distributed power access unit according to claim 1, characterized in that S103 includes: S1031. Starting from the first address of the low - priority block, perform jump - type probing towards the second address of the low - priority block according to the preset step size step; Among them, the first address is initialized as the start address, and the second address is initialized as the end address; S1032. If a certain jump - type probing in S1031 is successful, lock the corresponding address as the photovoltaic inverter address and perform S2; If all jump - type probings in S1031 are unsuccessful, use the address after the first address as the first address and return to S1031.

7. The inverter general reading method based on a distributed power access unit according to claim 1, characterized in that S103 includes: Starting from the first address of the low-priority block, perform the nth round of jump detection towards the second address of the low-priority block according to the preset step step n where n≥1; If a certain jump - type probing in the nth round is successful, lock the corresponding address as the photovoltaic inverter address and perform S2; If all the skip detections in the n-th round are unsuccessful, then starting from the first address of the low-priority block, a (n + 1)-th skip detection will be performed towards the second address of the low-priority block according to the preset step size step n+1 where 1 ≤ step n+1 < step n ; Among them, the first address is initialized as the start address, and the second address is initialized as the end address; Or, the first address is initialized as the end address, and the second address is initialized as the start address.

8. The general reading method of the inverter based on the distributed power access unit according to claim 1, characterized in that, In S1, the high - priority block and the low - priority block are dynamically updated based on the historical data of address self - adaptation; Among them, the initial value of the high - priority block is the manufacturer - default address or the user - specified address; The initial value of the low - priority block is the part of the address domain except the initial value of the high - priority block.

9. The inverter general reading method based on a distributed power access unit according to claim 8, wherein The method for dynamically updating the high - priority block and the low - priority block includes: Obtain the historical data of address self - adaptation within the preset period and count the number of times each address is successfully probed; Addresses with the number of successful detections greater than a first preset threshold are added to the high-priority block; Addresses with the number of successful detections less than a second preset threshold are added to the low-priority block; The remaining addresses remain unchanged; Among them, the second preset threshold is less than the first preset threshold.

10. A distributed power access unit, characterized in that, It adopts the general inverter reading method based on the distributed power access unit described in any one of claims 1-9.

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