CN-114665495-B - Control method, device and control system of energy storage system

Abstract

The invention discloses a control method, a device and a control system of an energy storage system, which are applied to a high-low-rate energy storage system, wherein the high-low-rate energy storage system comprises a high-rate energy storage subsystem and a low-rate energy storage subsystem, and by predicting a power grid side load curve and a power generation side power generation curve of a preset future time period, and obtaining an energy storage charging and discharging curve of a preset future time period, and adopting different high and low multiplying power control strategies for a high and low multiplying power energy storage system to enter a scene mainly charged or a scene mainly discharged based on the energy storage charging and discharging curve. The high-low-rate energy storage system provided by the invention can provide different charge and discharge strategies under different charge and discharge scenes, and can better cope with short-term peak load through the high-rate energy storage subsystem, so that the cycle life of the battery is prolonged, and the service life of the energy storage system is prolonged.

Inventors

• QIAN CHAO
• SHAO JUNWEI
• CAI XINGLONG
• DONG PUYUN
• XU QINGQING

Assignees

• 阳光储能技术有限公司

Dates

Publication Date

20260512

Application Date

20220413

Claims (17)

1. 1. The control method of the energy storage system is characterized by being applied to a high-low-rate energy storage system, wherein the high-low-rate energy storage system comprises a high-rate energy storage subsystem and a low-rate energy storage subsystem, and the control method comprises the following steps: predicting a power grid side load curve and a power generation side power generation curve of a preset future time period; Generating an energy storage charging and discharging curve of the high-low multiplying power energy storage system in the preset future time period based on the power grid side load curve and the power generation side power generation curve; Determining that the high-low-rate energy storage system enters a scene mainly charged or a scene mainly discharged according to the magnitude relation between the current state of charge of the low-rate energy storage subsystem and the minimum threshold value and the maximum threshold value of the low-rate state of charge; When the high-low multiplying power energy storage system enters a scene mainly subjected to charging or a scene mainly subjected to discharging, determining a corresponding high-low multiplying power control strategy based on the energy storage charging and discharging curve.
2. 2. The control method according to claim 1, wherein determining that the high-low-power energy storage system enters a charge-based scenario or a discharge-based scenario according to the magnitude relation between the current state of charge of the low-power energy storage subsystem and a low-power state of charge minimum threshold and a low-power state of charge maximum threshold, respectively, comprises: When the current state of charge is not greater than the minimum threshold value of the low-rate state of charge, determining that the high-low-rate energy storage system enters a scene mainly charged; and when the current state of charge is not less than the maximum threshold value of the low-rate state of charge, determining that the high-low-rate energy storage system enters a scene mainly subjected to discharge.
3. 3. The control method according to claim 1, wherein when the high-low-rate energy storage system enters a charge-dominant scene or a discharge-dominant scene, determining a corresponding high-low-rate control strategy based on the energy storage charge-discharge curve includes: when the high-low multiplying power energy storage system enters a scene mainly charged, the high-low multiplying power control strategy mainly charged by the energy storage system is adopted based on the energy storage charging and discharging curve, and the method specifically comprises the following steps: And controlling the high-low-rate energy storage system to charge mainly, and controlling the charge and discharge of the energy of the high-low-rate energy storage system in combination with different time scales of the energy storage charge and discharge curve.
4. 4. The control method according to claim 3, wherein the controlling the high-low-rate energy storage system to charge mainly includes controlling charging and discharging of energy of the high-low-rate energy storage system in combination with different time scales of the energy storage charging and discharging curve, including: acquiring high-rate to-be-charged energy of the high-rate energy storage subsystem and low-rate to-be-charged energy of the low-rate energy storage subsystem; dividing the energy storage charge-discharge curve into a long time scale, a medium time scale and a short time scale according to a preset dividing standard; Determining first charging energy corresponding to the long time scale, second charging energy corresponding to the medium time scale and third charging energy corresponding to the short time scale; When the high-low-rate energy storage system is mainly charged, determining a first charge-discharge control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem according to the magnitude relation between the first charge energy and the high-rate energy to be charged and the magnitude relation between the first charge energy and the low-rate energy to be charged; The charge-discharge time length in the first charge-discharge control strategy is determined based on the magnitude relation between the second charge energy and the third charge energy.
5. 5. The control method according to claim 4, wherein the predetermined dividing criteria is that, based on the positive and negative of the charge and discharge current and the minimum time scale T delta , when the charge and discharge mode is changed in nT delta , the high, middle and low time scales are divided according to the difference of n; If there is no current direction transition in nT delta , then n 1 is denoted as a long time scale factor, n 2 is denoted as a medium time scale factor, and n 3 is denoted as a low time scale factor, where n 1 ＞n 2 ＞n 3 is denoted to ensure that the minimum time interval is not less than the minimum time scale differentiation amount T min ; Correspondingly, n 1 T delta represents the long time scale, n 2 T delta represents the medium time scale, and n 3 T delta represents the short time scale.
6. 6. The control method according to claim 4, wherein when the high-low-rate energy storage system is mainly charged, determining a first charge-discharge control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem according to the magnitude relation between the first charge energy and the high-rate energy to be charged and the low-rate energy to be charged, includes: judging whether the first charging energy is larger than the sum of the high-rate energy to be charged and the low-rate energy to be charged; If so, under the condition that the electric quantity of the high-rate energy storage subsystem meets the long-time scale discharging working condition, charging and discharging the high-rate energy storage subsystem are conducted preferentially, then the low-rate energy storage subsystem is charged, the charging time length charges the low-rate energy storage subsystem by the larger one of the second charging energy and the third charging energy, and after the low-rate energy storage subsystem is fully charged, the high-rate energy storage subsystem is charged until the high-rate energy storage subsystem is fully charged.
7. 7. The control method of claim 6, wherein the first charge-discharge control strategy further comprises: If not, judging whether the first charging energy is larger than the low-rate energy to be charged or not; And when the high-low-rate energy storage subsystem has discharge requirements, the high-rate energy storage subsystem is controlled to discharge, when the electric quantity of the high-rate energy storage subsystem is low, the high-rate energy storage subsystem is charged preferentially, and the low-rate energy storage subsystem is charged again under the condition that the discharge function of the high-rate energy storage subsystem is met.
8. 8. The control method of claim 7, wherein the first charge-discharge control strategy further comprises: If the first charging energy is not larger than the low-rate energy to be charged, judging whether the sum of the first charging energy and the high-rate energy to be charged is larger than the low-rate energy to be charged or not; If so, charging the low-rate energy storage subsystem preferentially, wherein the charging time period charges the low-rate energy storage subsystem by the larger one of the second charging energy and the third charging energy; and when the high-low-rate energy storage system does not have the discharge requirement, controlling the high-rate energy storage subsystem to charge the low-rate energy storage subsystem until the residual energy in the high-rate energy storage subsystem is charged into the low-rate energy storage subsystem.
9. 9. The control method of claim 8, wherein the first charge-discharge control strategy further comprises: And if not, charging the high-rate energy storage subsystem preferentially, wherein the charging time length is longer than the larger of the second charging energy and the third charging energy to charge the high-rate energy storage subsystem, and when the high-rate energy storage subsystem is full, charging the low-rate energy storage subsystem again.
10. 10. The control method according to claim 1, wherein when the high-low-rate energy storage system enters a charge-dominant scene or a discharge-dominant scene, determining a corresponding high-low-rate control strategy based on the energy storage charge-discharge curve includes: When the high-low multiplying power energy storage system enters a scene mainly based on discharge, the high-low multiplying power control strategy mainly based on discharge of the energy storage system is adopted based on the energy storage charging and discharging curve, and the method specifically comprises the following steps: and controlling the high-low-rate energy storage system to discharge mainly, and controlling the energy of the high-low-rate energy storage system to charge and discharge according to different time scales of the energy storage charge and discharge curve, wherein the low-rate energy storage subsystem mainly discharges.
11. 11. The control method according to claim 10, wherein the controlling the discharging of the high-low-rate energy storage system is mainly performed, and the charging and discharging control is performed by combining the energy of the high-low-rate energy storage system with different time scales of the energy storage charging and discharging curve, including: acquiring high-rate to-be-discharged energy of the high-rate energy storage subsystem and low-rate to-be-discharged energy of the low-rate energy storage subsystem; dividing the energy storage charge-discharge curve into a long time scale, a medium time scale and a short time scale according to a preset dividing standard; determining first discharge energy corresponding to the long time scale, second discharge energy corresponding to the medium time scale and third discharge energy corresponding to the short time scale; When the high-low-rate energy storage system mainly discharges, determining a second charge-discharge control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem according to the magnitude relation between the first discharge energy and the high-rate energy to be discharged and the magnitude relation between the first discharge energy and the low-rate energy to be discharged; The charge-discharge time length in the second charge-discharge control strategy is determined based on the magnitude relation between the second discharge energy and the third discharge energy.
12. 12. The control method according to claim 11, wherein when the high-low-rate energy storage system is mainly discharged, determining a second charge-discharge control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem according to the magnitude relation between the first discharge energy and the high-rate energy to be discharged and the low-rate energy to be discharged, includes: judging whether the first discharge energy is larger than the sum of the high-rate energy to be discharged and the low-rate energy to be discharged; If so, the low-rate energy storage subsystem is controlled to discharge only, the high-rate energy storage subsystem is controlled to charge and discharge independently, and the charging and discharging time length takes the larger of the second discharging energy and the third discharging energy as the charging and discharging of the high-rate energy storage subsystem until the high-rate energy storage subsystem and the low-rate energy storage subsystem are discharged.
13. 13. The control method of claim 12, wherein the second charge-discharge control strategy further comprises: If not, judging whether the first discharge energy is larger than the low-rate energy to be discharged or not; if so, the low-rate energy storage subsystem is preferentially controlled to discharge, the larger one of the second discharge energy and the third discharge energy is used as the low-rate energy storage subsystem in the discharge time period, the high-rate energy storage subsystem is controlled to charge and discharge, and when the high-rate energy storage subsystem is about to be fully charged, the high-rate energy storage subsystem is mainly discharged, so that the low-rate energy storage subsystem is ensured to discharge only.
14. 14. The control method of claim 13, wherein the second charge-discharge control strategy further comprises: when the first discharge energy is not larger than the low-rate to-be-discharged energy, judging whether the sum of the first discharge energy and the high-rate to-be-discharged energy is larger than the low-rate to-be-discharged energy or not; If so, the low-rate energy storage subsystem is preferably discharged, the discharging time length takes the larger one of the second discharging energy and the third discharging energy as the low-rate energy storage subsystem, the high-rate energy storage subsystem is charged when the high-low rate energy storage subsystem has a charging requirement, and the low-rate energy storage subsystem is controlled to discharge to the high-rate energy storage subsystem when the high-low rate energy storage subsystem has no charging requirement.
15. 15. The control method of claim 14, wherein the second charge-discharge control strategy further comprises: and if not, discharging the high-rate energy storage subsystem preferentially, wherein the discharging time length takes the larger one of the second discharging energy and the third discharging energy as the high-rate energy storage subsystem, and discharging the low-rate energy storage subsystem when the high-rate energy storage subsystem is empty.
16. 16. The control device of the energy storage system is characterized by being applied to a high-low-rate energy storage system, wherein the high-low-rate energy storage system comprises a high-rate energy storage subsystem and a low-rate energy storage subsystem, and the control device comprises: The curve prediction unit is used for predicting a power grid side load curve and a power generation side power generation curve of a preset future time period; The curve generation unit is used for generating an energy storage charging and discharging curve of the high-low-rate energy storage system in the preset future time period based on the power grid side load curve and the power generation side power generation curve; The charge-discharge scene determining unit is used for determining that the high-low-magnification energy storage system enters a scene mainly charged or a scene mainly discharged according to the magnitude relation between the current state of charge of the low-magnification energy storage subsystem and the minimum threshold value and the maximum threshold value of the low-magnification state of charge; And the control unit is used for determining a corresponding high-low rate control strategy based on the energy storage charging and discharging curve when the high-low rate energy storage system enters a scene mainly charged or a scene mainly discharged.
17. 17. An energy storage system comprising the control device of claim 16.

Description

Control method, device and control system of energy storage system Technical Field The present invention relates to the field of energy storage systems, and in particular, to a control method, apparatus and control system for an energy storage system. Background In energy storage systems, particularly lithium iron phosphate energy storage systems, the cycle life of a battery is typically calculated in complete charge-discharge cycles, whereas when the battery is not fully charged, cycles at different depths of discharge (Depth Of Discharge, DOD) will translate the cycle life of the battery. In the lithium iron phosphate energy storage system, if the depth of discharge is always in the plateau period, the estimation of the battery SOC (State of Charge) will deviate, so that the error of the cycle life conversion coefficient of the battery is larger, and the battery manufacturer will increase the cycle life conversion coefficient as much as possible, so as to reduce the service life of the battery, resulting in the reduction of the cycle life of the battery, and further in the reduction of the service life of the energy storage system. Disclosure of Invention In view of the above, the present invention discloses a control method, a device and a control system for an energy storage system, so as to improve the cycle life of a battery and prolong the service life of the energy storage system. The control method of the energy storage system is applied to a high-low-rate energy storage system, wherein the high-low-rate energy storage system comprises a high-rate energy storage subsystem and a low-rate energy storage subsystem, and the control method comprises the following steps: predicting a power grid side load curve and a power generation side power generation curve of a preset future time period; Generating an energy storage charging and discharging curve of the high-low multiplying power energy storage system in the preset future time period based on the power grid side load curve and the power generation side power generation curve; Determining that the high-low-rate energy storage system enters a scene mainly charged or a scene mainly discharged according to the magnitude relation between the current state of charge of the low-rate energy storage subsystem and the minimum threshold value and the maximum threshold value of the low-rate state of charge; When the high-low multiplying power energy storage system enters a scene mainly subjected to charging or a scene mainly subjected to discharging, determining a corresponding high-low multiplying power control strategy based on the energy storage charging and discharging curve. Optionally, the determining, according to the magnitude relation between the current state of charge of the low-rate energy storage subsystem and the minimum threshold value of the low-rate state of charge and the maximum threshold value of the low-rate state of charge, that the high-rate energy storage subsystem enters a scenario mainly charged or a scenario mainly discharged includes: When the current state of charge is not greater than the minimum threshold value of the low-rate state of charge, determining that the high-low-rate energy storage system enters a scene mainly charged; and when the current state of charge is not less than the maximum threshold value of the low-rate state of charge, determining that the high-low-rate energy storage system enters a scene mainly subjected to discharge. Optionally, when the high-low rate energy storage system enters a charging-based scene or a discharging-based scene, determining a corresponding high-low rate control strategy based on the energy storage charging-discharging curve, including: When the high-low multiplying power energy storage system enters a scene mainly charged, adopting a high-low multiplying power control strategy mainly charged by the energy storage system based on the energy storage charging and discharging curve, and specifically comprising the following steps: And controlling the high-low-rate energy storage system to charge mainly, and controlling the charge and discharge of the energy of the high-low-rate energy storage system in combination with different time scales of the energy storage charge and discharge curve. Optionally, the controlling the high-low multiplying power energy storage system to charge mainly includes performing charge-discharge control on energy of the high-low multiplying power energy storage system in combination with different time scales of the energy storage charge-discharge curve, including: acquiring high-rate to-be-charged energy of the high-rate energy storage subsystem and low-rate to-be-charged energy of the low-rate energy storage subsystem; dividing the energy storage charge-discharge curve into a long time scale, a medium time scale and a short time scale according to a preset dividing standard; Determining first charging energy corresponding to the long time scale, second charging