Method, device, storage medium and electronic equipment for quickly identifying load mutation

Abstract

The application discloses a method and device for rapidly identifying load mutation, a storage medium and electronic equipment, and the method comprises the following steps: detecting the instantaneous output power P of an energy storage inverter once every PWM switching cycle in the same identification cycle; calculating the load mutation depth d corresponding to each PWM switching cycle according to the following formula: wherein P0 is the instantaneous output power of the current PWM switching cycle, P1 is the instantaneous output power of the upper half of the identification cycle, and P2 is the instantaneous output power of the previous identification cycle; and adjusting the control parameters of the energy storage inverter according to the calculation result to control the output duty cycle of the current PWM switching until the load mutation depth d is less than a first preset threshold. The load mutation identification time of the application only needs one PWM switching cycle, which can effectively shorten the dynamic response delay time, guarantee the rapidity of load mutation detection, and guarantee the accuracy of load mutation detection.

Description

Technical Field

[0001] This invention relates to the field of energy storage inverter technology, and in particular to methods, devices, storage media and electronic devices for rapidly identifying load changes. Background Technology

[0002] In off-grid mode, energy storage inverters need to quickly identify load abrupt changes. Traditional methods identify these changes by detecting the 20ms effective value of the output power. However, this requires detecting the power's effective value over 20ms, resulting in a 20ms delay in dynamic response and failing to achieve optimal load abrupt change identification. Furthermore, the traditional method requires a single detection unit to monitor multiple instantaneous power changes compared to the previous cycle, which can easily lead to misjudgments, especially with RCD loads. The accuracy and speed of load abrupt change identification severely restrict the development of energy storage inverters. Summary of the Invention

[0003] The purpose of this invention is to provide a method, apparatus, storage medium, and electronic device for rapid identification of load mutations. The load mutation identification time only requires one PWM switching cycle, which can effectively shorten the dynamic response delay time and ensure both the speed and accuracy of load mutation detection.

[0004] To achieve the above objectives, this invention discloses a method for rapidly identifying load surges, applicable to energy storage inverters in off-grid mode. The method for rapidly identifying load surges includes the following steps:

[0005] S1. Within the same identification cycle, the instantaneous output power P of the energy storage inverter is detected once every PWM switching cycle.

[0006] S2. Calculate the load transition depth d for each PWM switching cycle according to the following formula:

[0007]

[0008] Where P0 is the instantaneous output power of the current PWM switching cycle, P1 is the instantaneous output power of the first half of the identification cycle, P2 is the instantaneous output power of the previous identification cycle, A is the first weighting factor, and B is the second weighting factor.

[0009] S3. Adjust the control parameters of the energy storage inverter according to the calculation results to control the output duty cycle of the current PWM switch until the load change depth d is less than the first preset threshold.

[0010] Preferably, the identification period is twice the power frequency period of the power grid where the energy storage inverter is located.

[0011] Preferably, step S1 specifically includes:

[0012] S11. Within the same identification cycle, the instantaneous output voltage U and instantaneous output current I of the energy storage inverter are detected once every PWM switching cycle.

[0013] S12. Calculate the instantaneous output power P of the energy storage inverter in each PWM switching cycle according to the following formula:

[0014] P = U × I.

[0015] Preferably, after step S12, the method further includes:

[0016] S13. Sequentially save all instantaneous output power P within the same recognition period using sliding mode.

[0017] Preferably, step S3 specifically includes:

[0018] S31. If the load change depth d corresponding to any PWM switching cycle is greater than or equal to the second preset threshold, then it is determined that the output load of the energy storage inverter has changed within the current identification cycle.

[0019] S32. Adjust the Kp parameter value and Ki parameter value of the control loop of the energy storage inverter according to the load mutation depth d corresponding to the current PWM switching cycle, so as to control the output duty cycle of the current PWM switch until the load mutation depth d corresponding to at least one PWM switching cycle after the current PWM switching cycle in the current identification cycle is less than or equal to the first preset threshold.

[0020] Preferably, both the first weighting factor A and the second weighting factor B are 50%.

[0021] Preferably, the instantaneous output power P of each PWM switching cycle within the same identification period has the same phase angle.

[0022] Accordingly, the present invention also discloses a device for rapidly identifying load surges, applicable to energy storage inverters in off-grid mode, the device comprising:

[0023] The detection module is configured to detect the instantaneous output power P of the energy storage inverter once every PWM switching cycle within the same identification period;

[0024] The processing unit is configured to calculate the load mutation depth d corresponding to each PWM switching cycle according to the following formula:

[0025]

[0026] Where P0 is the instantaneous output power of the current PWM switching cycle, P1 is the instantaneous output power of the previous PWM switching cycle, P2 is the instantaneous output power of the previous two PWM switching cycles, A is the first weighting factor, and B is the second weighting factor.

[0027] The adjustment unit is configured to adjust the control parameters of the energy storage inverter based on the calculation results, so as to control the output duty cycle of the current PWM switch until the load mutation depth d is less than a first preset threshold.

[0028] Accordingly, the present invention also discloses a storage medium for storing a computer program, which, when executed by a processor, implements the method for rapidly identifying load mutations as described above.

[0029] Accordingly, the present invention also discloses an electronic device comprising a memory and a processor, wherein the memory stores executable instructions, and when the executable instructions are executed by at least one processor, the processor performs the fast load mutation identification method as described above.

[0030] Compared with the prior art, the present invention calculates the load mutation depth d corresponding to each PWM switching cycle in the same identification cycle, and adjusts the control parameters of the energy storage inverter according to the calculation results so that the load mutation depth d is less than the first preset threshold. Its load mutation identification time only requires one PWM switching cycle, which can effectively shorten the dynamic response delay time, ensuring both the speed and accuracy of load mutation detection. Attached Figure Description

[0031] Figure 1 This is a flowchart of the rapid load mutation identification method of the present invention;

[0032] Figure 2 This is the control loop of the rapid load mutation identification method of the present invention;

[0033] Figure 3 This is a schematic diagram showing the change in instantaneous output power P of the energy storage inverter of the present invention. Detailed Implementation

[0034] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0035] Please see Figures 1-3 As shown, the rapid load change identification method of this embodiment is applicable to energy storage inverters in off-grid mode. The rapid load change identification method includes the following steps:

[0036] S1. Within the same identification cycle, the instantaneous output power P of the energy storage inverter is detected once every PWM switching cycle.

[0037] Preferably, the identification period is twice the power frequency period of the power grid where the energy storage inverter is located.

[0038] Preferably, the instantaneous output power P of each PWM switching cycle within the same identification period has the same phase angle.

[0039] This embodiment uses the energy storage inverter with AC mains power as the input voltage as an example for illustration:

[0040] With a mains input voltage of 220V and an AC frequency of 50Hz, the power frequency period in this embodiment is 20ms, which means the identification period in this embodiment is 20ms.

[0041] Assuming the PWM switching frequency of the energy storage inverter in this embodiment is 20kHz, then each PWM switching cycle is 50μs. Therefore, 800 instantaneous output powers P can be detected within the same identification cycle, with each instantaneous output power P corresponding to one PWM switching cycle. Since the instantaneous output power P of each PWM switching cycle within the same identification cycle has the same phase angle, all instantaneous output powers P within the same identification cycle have the same phase angle, facilitating subsequent direct calculation of load surges.

[0042] S2. Calculate the load transition depth d for each PWM switching cycle according to the following formula:

[0043]

[0044] Where P0 is the instantaneous output power of the current PWM switching cycle, P1 is the instantaneous output power of the first half of the identification cycle, P2 is the instantaneous output power of the previous identification cycle, A is the first weighting factor, and B is the second weighting factor.

[0045] In this embodiment, P1 is the instantaneous output power during the first 20ms of the current PWM switching cycle, and P2 is the instantaneous output power during the first 40ms of the current PWM switching cycle.

[0046] Preferably, both the first weighting factor A and the second weighting factor B are 50%.

[0047] It is understood that in this embodiment, the two parts of the above formula are set to have the same weight. In other embodiments, the two parts of the above formula can be set to different weights according to actual needs to meet more calculation requirements.

[0048] S3. Adjust the control parameters of the energy storage inverter according to the calculation results to control the output duty cycle of the current PWM switch until the load change depth d is less than the first preset threshold.

[0049] Preferably, step S1 specifically includes:

[0050] S11. Within the same identification cycle, the instantaneous output voltage U and instantaneous output current I of the energy storage inverter are detected once every PWM switching cycle.

[0051] S12. Calculate the instantaneous output power P of the energy storage inverter in each PWM switching cycle according to the following formula:

[0052] P = U × I.

[0053] Preferably, after step S12, the method further includes:

[0054] S13. Sequentially save all instantaneous output power P within the same recognition period using sliding mode.

[0055] Understandably, all of the above data is stored in the RAM area of ​​the control chip, and the instantaneous output power P of the energy storage inverter under each PWM switching cycle is saved in sliding mode.

[0056] Preferably, step S3 specifically includes:

[0057] S31. If the load change depth d corresponding to any PWM switching cycle is greater than or equal to the second preset threshold, then it is determined that the output load of the energy storage inverter has changed within the current identification cycle.

[0058] Specifically, the second preset threshold is set to 10%. That is, when the load change depth d corresponding to any PWM switching cycle is greater than or equal to 10%, it is determined that the output load of the energy storage inverter has changed within the current identification cycle, and at this time, the energy storage inverter enters the fast response mode.

[0059] S32. Adjust the Kp parameter value and Ki parameter value of the control loop of the energy storage inverter according to the load mutation depth d corresponding to the current PWM switching cycle, so as to control the output duty cycle of the current PWM switch until the load mutation depth d corresponding to at least one PWM switching cycle after the current PWM switching cycle in the current identification cycle is less than or equal to the first preset threshold.

[0060] Specifically, the first preset threshold here is set to 5%. That is, when the energy storage inverter enters the fast response mode, the control chip controls the Kp and Ki parameter values ​​of the control loop according to the load change depth d corresponding to the current PWM switching cycle, so as to change the dynamic response characteristics of the control loop and realize the control of the output duty cycle of the current PWM switch. This greatly improves the dynamic response characteristics of the control loop, significantly improves the output stability of the energy storage inverter, and solves the problem of severe voltage drop in the output of the energy storage inverter caused by untimely load change recognition.

[0061] After the above adjustments, if the load mutation depth d corresponding to at least one PWM switching cycle after the current PWM switching cycle in the current identification cycle is less than or equal to the first preset threshold, then the energy storage inverter will resume entering the steady-state mode to ensure the steady-state accuracy of the energy storage inverter.

[0062] It should be noted that the control methods such as input, feedback, compensation, and adjustment of the control loop are well known to those skilled in the art and will not be elaborated here.

[0063] Accordingly, the present invention also discloses a device for rapidly identifying load surges, applicable to energy storage inverters in off-grid mode, the device comprising:

[0064] The detection module is configured to detect the instantaneous output power P of the energy storage inverter once every PWM switching cycle within the same identification period;

[0065] The processing unit is configured to calculate the load mutation depth d corresponding to each PWM switching cycle according to the following formula:

[0066]

[0067] Where P0 is the instantaneous output power of the current PWM switching cycle, P1 is the instantaneous output power of the previous PWM switching cycle, P2 is the instantaneous output power of the previous two PWM switching cycles, A is the first weighting factor, and B is the second weighting factor.

[0068] The adjustment unit is configured to adjust the control parameters of the energy storage inverter based on the calculation results, so as to control the output duty cycle of the current PWM switch until the load mutation depth d is less than a first preset threshold.

[0069] Accordingly, the present invention also discloses a storage medium for storing a computer program, which, when executed by a processor, implements the method for rapidly identifying load mutations as described above.

[0070] Accordingly, the present invention also discloses an electronic device comprising a memory and a processor, wherein the memory stores executable instructions, and when the executable instructions are executed by at least one processor, the processor performs the fast load mutation identification method as described above.

[0071] Combination Figures 1-3The present invention calculates the load mutation depth d corresponding to each PWM switching cycle in the same identification cycle, and adjusts the control parameters of the energy storage inverter according to the calculation results so that the load mutation depth d is less than the first preset threshold. Its load mutation identification time only requires one PWM switching cycle, which can effectively shorten the dynamic response delay time, ensuring both the speed and accuracy of load mutation detection.

[0072] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for rapidly identifying load surges, applicable to energy storage inverters in off-grid mode, characterized in that, The rapid method for identifying load mutations includes the following steps: Within the same identification cycle, the instantaneous output power P of the energy storage inverter is detected once every PWM switching cycle; The load transition depth d for each PWM switching cycle is calculated sequentially using the following formula: Where P0 is the instantaneous output power of the current PWM switching cycle, P1 is the instantaneous output power of the first half of the identification cycle, P2 is the instantaneous output power of the previous identification cycle, A is the first weighting factor, and B is the second weighting factor. The control parameters of the energy storage inverter are adjusted based on the calculation results to control the output duty cycle of the current PWM switch until the load change depth d is less than the first preset threshold.

2. The method for rapidly identifying load mutations as described in claim 1, characterized in that, The identification period is twice the power frequency period of the power grid where the energy storage inverter is located.

3. The rapid load mutation identification method as described in claim 1, characterized in that, Within the same identification cycle, the instantaneous output power P of the energy storage inverter is detected once every PWM switching cycle, specifically including: Within the same identification cycle, the instantaneous output voltage U and instantaneous output current I of the energy storage inverter are detected once every PWM switching cycle; The instantaneous output power P of the energy storage inverter during each PWM switching cycle is calculated using the following formula: P = U × I.

4. The rapid method for identifying load mutations as described in claim 3, characterized in that, The instantaneous output power P of the energy storage inverter in each PWM switching cycle is calculated according to the following formula: P = U × I, followed by: The instantaneous output power P within the same recognition period is saved sequentially using sliding mode.

5. The method for rapidly identifying load mutations as described in claim 1, characterized in that, The step of adjusting the control parameters of the energy storage inverter based on the calculation results to control the output duty cycle of the current PWM switch until the load change depth d is less than the first preset threshold specifically includes: If the load change depth d corresponding to any PWM switching cycle is greater than or equal to the second preset threshold, then the output load of the energy storage inverter is determined to have changed within the current identification cycle. The Kp and Ki parameter values ​​of the control loop of the energy storage inverter are adjusted according to the load mutation depth d corresponding to the current PWM switching cycle to control the output duty cycle of the current PWM switch until the load mutation depth d corresponding to at least one PWM switching cycle after the current PWM switching cycle in the current identification cycle is less than or equal to the first preset threshold.

6. The method for rapidly identifying load mutations as described in claim 1, characterized in that, The first weighting factor A and the second weighting factor B are both 50%.

7. The rapid method for identifying load mutations as described in claim 1, characterized in that, The instantaneous output power P of each PWM switching cycle within the same identification period has the same phase angle.

8. A device for rapidly identifying sudden load changes, applicable to energy storage inverters in off-grid mode, characterized in that, The rapid load mutation identification device includes: The detection module is configured to detect the instantaneous output power P of the energy storage inverter once every PWM switching cycle within the same identification period; The processing unit is configured to calculate the load mutation depth d corresponding to each PWM switching cycle according to the following formula: Where P0 is the instantaneous output power of the current PWM switching cycle, P1 is the instantaneous output power of the previous PWM switching cycle, P2 is the instantaneous output power of the previous two PWM switching cycles, A is the first weighting factor, and B is the second weighting factor. The adjustment unit is configured to adjust the control parameters of the energy storage inverter based on the calculation results, so as to control the output duty cycle of the current PWM switch until the load mutation depth d is less than a first preset threshold.

9. A storage medium for storing computer programs, characterized in that: When the program is executed by the processor, it implements the method for rapidly identifying load mutations as described in any one of claims 1 to 7.

10. An electronic device, characterized in that: It includes a memory and a processor, wherein the memory stores executable instructions, and when the executable instructions are executed by at least one processor, the processor performs the fast load mutation identification method as described in any one of claims 1 to 7.

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