Energy storage converter charging and discharging control method and system

Abstract

The application provides a kind of energy storage converter charge-discharge control method and system, and the charge-discharge control method includes: S1: obtaining the charge-discharge efficiency table of energy storage converter;S2: after energy storage converter receives charge-discharge instruction, start charging / discharging to charge-discharge object;S3: during the process of charging and discharging, the current voltage value of charge-discharge object is monitored in real time or periodically, and the corresponding highest charge-discharge efficiency is obtained according to the charge-discharge efficiency table, and then the required power and rated power ratio corresponding to the highest charge-discharge efficiency is obtained;S4: according to the required power and rated power ratio, the required power of energy storage converter during charging and discharging is calculated, and it is simultaneously adjusted as the actual power of energy storage converter during charging and discharging.This scheme can make energy storage converter run with the highest charge-discharge efficiency corresponding to the current voltage value of charge-discharge object during the process of charging and discharging, which can improve the charge-discharge efficiency and reduce the energy loss during the process of charging and discharging.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a charging and discharging control method and system for an energy storage converter. Background Technology

[0002] A power storage converter (PCS) controls the charging and discharging process of a battery, converting AC to DC power, and can directly supply power to AC loads in the absence of a power grid. As a key component in energy storage conversion, the charging and discharging efficiency of the power storage converter is a crucial performance parameter. Existing power storage converters only focus on the product's peak efficiency point, neglecting the actual charging and discharging efficiency of the power storage converter.

[0003] Currently, the mainstream charging and discharging control method for energy storage converters is constant power charging and discharging. The host computer inputs the target charging and discharging power, and the energy storage converter operates continuously at that power. However, the voltage of the energy storage converter is constantly changing during both charging and discharging. Under different battery voltages and power levels, the actual charging and discharging efficiency of the energy storage converter varies. Some manufacturers also offer constant current and constant voltage charging and discharging modes; however, constant power, constant voltage, and constant current charging and discharging cannot ensure that the energy storage converter always operates within its high-efficiency range. Summary of the Invention

[0004] Based on the problems existing in the prior art, the present invention aims to solve the technical problem that the existing charge and discharge control methods cannot enable the energy storage converter to maintain a high charge and discharge efficiency at all times.

[0005] This invention provides a charging and discharging control method for an energy storage converter, comprising the following steps:

[0006] S1: Obtain the charging / discharging efficiency table of the energy storage converter. The charging / discharging efficiency table includes the highest charging / discharging efficiency of the energy storage converter corresponding to different voltage values ​​of the charging / discharging object during the charging / discharging process, and the ratio of the actual power of the energy storage converter to the rated power when charging / discharging.

[0007] S2: After receiving the charging / discharging command from the background, the energy storage converter begins to charge / discharge the object.

[0008] S3: During the charging / discharging process, monitor the current voltage value of the object being charged / discharged in real time or periodically, obtain the highest charging / discharging efficiency corresponding to the current voltage value according to the charging / discharging efficiency table, and then obtain the ratio of the required power to the rated power according to the highest charging / discharging efficiency.

[0009] S4: Calculate the required power of the energy storage converter during charging / discharging based on the ratio of the required power to the rated power, and simultaneously adjust it to the actual power of the energy storage converter during charging / discharging, so that the energy storage converter operates at the highest charging / discharging efficiency corresponding to the current voltage value of the object being charged / discharged throughout the charging / discharging process.

[0010] According to an embodiment of the present invention, in step S2, before the energy storage converter starts charging / discharging the object after receiving the charging / discharging command, the following steps are also included:

[0011] Obtain the initial voltage value of the object to be charged / discharged, look up the charging / discharge efficiency table to get the highest charging / discharge efficiency corresponding to the initial voltage value, and look up the charging / discharge efficiency table again to get the ratio of the actual power to the rated power of the energy storage converter when charging / discharging corresponding to the highest charging / discharging efficiency;

[0012] The initial power at which the energy storage converter begins charging / discharging is calculated based on the ratio of the actual power to the rated power. The energy storage converter then begins charging / discharging the object using the calculated initial power.

[0013] According to one embodiment of the present invention, both the initial voltage value and the current voltage value are acquired by a voltage sensor.

[0014] According to an embodiment of the present invention, in step S3, when obtaining the highest charge / discharge efficiency corresponding to the current voltage value based on the charge / discharge efficiency table, and when obtaining the ratio of actual power to rated power corresponding to the highest charge / discharge efficiency based on the highest charge / discharge efficiency, linear interpolation is used to obtain the highest charge / discharge efficiency corresponding to the current voltage value that is not recorded in the charge / discharge efficiency table, and the ratio of actual power to rated power of the energy storage converter corresponding to the highest charge / discharge efficiency.

[0015] According to one embodiment of the present invention, the charge / discharge efficiency of the energy storage converter is obtained by multiple measurements using a power analyzer at different voltage points on the DC side of the energy storage power station system and at different power points of the energy storage converter.

[0016] According to one embodiment of the present invention, the object being charged / discharged is a battery pack.

[0017] The present invention also provides a charging and discharging control system for an energy storage converter, comprising:

[0018] The charge / discharge efficiency table records the highest charge / discharge efficiency of the energy storage converter corresponding to different voltage values ​​of the object being charged / discharged during the charging / discharging process, as well as the ratio of the power required by the energy storage converter to the rated power when charging / discharging.

[0019] The communication module establishes a communication connection with the energy storage converter and is used to send the received charging / discharging commands from the background to the energy storage converter. The energy storage converter charges / discharges the object according to the received charging / discharging commands.

[0020] A voltage monitoring module is used to monitor the current voltage value of the object being charged / discharged in real time or periodically during the charging / discharging process;

[0021] The query module establishes a communication or electrical connection with the charge / discharge efficiency table and the voltage monitoring module respectively, in order to query the charge / discharge efficiency table to obtain the highest charge / discharge efficiency corresponding to the current voltage value of the charge / discharge object and the ratio of the required power to the rated power corresponding to the highest charge / discharge efficiency;

[0022] The calculation module establishes a communication or electrical connection with the query module to calculate the required power of the energy storage converter during charging / discharging based on the ratio of the required power to the rated power.

[0023] The adjustment module establishes communication or electrical connections with the calculation module and the energy storage converter, respectively, to simultaneously and synchronously adjust the actual power of the energy storage converter during charging / discharging based on the calculated power required by the energy storage converter during charging / discharging.

[0024] According to one embodiment of the present invention, the voltage monitoring module is a voltage sensor.

[0025] The beneficial effects of this invention are:

[0026] This invention provides a charging and discharging control method and system for an energy storage converter. Based on the voltage change characteristics of the charging / discharging object during the charging / discharging process, the method collects the current voltage value of the charging / discharging object in real time or periodically, obtains the highest charging / discharging efficiency corresponding to the current voltage value according to a charging / discharging efficiency table, and then obtains the ratio of the required power to the rated power based on the highest charging / discharging efficiency. Next, the method calculates the required power of the energy storage converter during charging / discharging based on the obtained ratio of required power to rated power, and simultaneously adjusts it to the actual power of the energy storage converter during charging / discharging. This ensures that the energy storage converter operates at the highest charging / discharging efficiency corresponding to the current voltage value of the charging / discharging object throughout the charging / discharging process, thereby improving charging / discharging efficiency and reducing energy loss during charging / discharging. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments or prior art, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic block diagram of a charging and discharging control system for an energy storage converter provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic flowchart of the charging and discharging control method for an energy storage converter provided in an embodiment of the present invention. Detailed Implementation

[0030] The following descriptions of the embodiments are made with reference to the accompanying illustrations to illustrate specific embodiments in which the invention can be implemented.

[0031] This invention provides a charging and discharging control system for an energy storage converter, the structure of which is as follows: Figure 1 As shown, the system includes a charge / discharge efficiency table, a communication module, a voltage monitoring module, a query module, a calculation module, and an adjustment module. The charge / discharge efficiency table records the highest charge / discharge efficiency of the energy storage converter corresponding to different voltage values ​​of the object being charged / discharged, and the ratio of the power required for charging / discharging to the rated power. The communication module establishes a communication connection with the energy storage converter and sends received charge / discharge commands from the background to the energy storage converter, which then charges / discharges the object according to the received commands. The voltage monitoring module monitors the current voltage value of the object being charged / discharged in real time or periodically during the charging / discharging process. Specifically, the voltage monitoring module... The system is a voltage sensor. The query module establishes communication or electrical connections with the charge / discharge efficiency table and the voltage monitoring module to query the charge / discharge efficiency table to obtain the highest charge / discharge efficiency corresponding to the current voltage value of the object being charged / discharged, as well as the ratio of the required power to the rated power corresponding to the highest charge / discharge efficiency. The calculation module establishes communication or electrical connections with the query module to calculate the required power of the energy storage converter during charging / discharging based on the obtained ratio of the required power to the rated power. The adjustment module establishes communication or electrical connections with the calculation module and the energy storage converter to simultaneously and synchronously adjust the actual power of the energy storage converter during charging / discharging based on the calculated required power of the energy storage converter.

[0032] This invention provides a charging and discharging control method for an energy storage converter, the steps of which are as follows: Figure 2 As shown, it includes the following steps:

[0033] S1: Obtain the charging / discharging efficiency table of the energy storage converter. The charging / discharging efficiency table includes the highest charging / discharging efficiency of the energy storage converter corresponding to different voltage values ​​of the charging / discharging object during the charging / discharging process, and the ratio of the actual power of the energy storage converter to the rated power when charging / discharging.

[0034] S2: After receiving the charging / discharging command from the background, the energy storage converter begins to charge / discharge the object.

[0035] S3: During the charging / discharging process, monitor the current voltage value of the object being charged / discharged in real time or periodically, obtain the highest charging / discharging efficiency corresponding to the current voltage value according to the charging / discharging efficiency table, and then obtain the ratio of the required power to the rated power according to the highest charging / discharging efficiency.

[0036] S4: Calculate the required power of the energy storage converter during charging / discharging based on the ratio of the required power to the rated power, and simultaneously adjust it to the actual power of the energy storage converter during charging / discharging, so that the energy storage converter operates at the highest charging / discharging efficiency corresponding to the current voltage value of the object being charged / discharged throughout the charging / discharging process.

[0037] According to an embodiment of the present invention, in step S2, before the energy storage converter starts charging / discharging the object after receiving the charging / discharging command, the following steps are also included:

[0038] Obtain the initial voltage value of the object to be charged / discharged, look up the charging / discharge efficiency table to get the highest charging / discharge efficiency corresponding to the initial voltage value, and look up the charging / discharge efficiency table again to get the ratio of the actual power to the rated power of the energy storage converter when charging / discharging corresponding to the highest charging / discharging efficiency;

[0039] The initial power at which the energy storage converter begins charging / discharging is calculated based on the ratio of the actual power to the rated power. The energy storage converter then begins charging / discharging the object using the calculated initial power.

[0040] Specifically, taking a battery pack as the object of charging / discharging, the energy storage converter provided by the present invention performs the following process when charging / discharging the battery pack:

[0041] Step 1: Using a power analyzer, multiple measurements are taken at different voltage points on the DC side of the energy storage power station system and at the power point of the energy storage converter to obtain a table of charge / discharge efficiency of the energy storage converter when charging / discharging the battery pack. Table 1 shows the charge / discharge efficiency table of a certain model of energy storage converter. It records the highest charge / discharge efficiency of the energy storage converter corresponding to different voltage values ​​of the battery pack during the charging / discharging process, as well as the ratio of the power required by the energy storage converter to the rated power when charging / discharging. Specifically, different specifications and models of energy storage converters correspond to different charge / discharge efficiency tables, while energy storage converters of the same specification and model can share a single charge / discharge efficiency table.

[0042] As can be seen from Table 1, at the same voltage point of the battery pack, the efficiency of the same type of energy storage inverter varies by 1%-3% when charged / discharged at different power. In one charge / discharge cycle, the difference in charge / discharge efficiency can reach 2%-6%. In addition, more heat is generated when charging / discharging at low efficiency (a larger proportion of electrical energy is converted into heat energy when operating at low efficiency; the proportion of electrical energy converted into heat energy is relatively smaller when operating at high efficiency), and additional heat dissipation equipment is required, which consumes more energy.

[0043] It should be noted that Table 1 only shows the maximum charge / discharge efficiency of the energy storage converter and the ratio of the power required for charging / discharging to the rated power of the energy storage converter for three voltage values ​​(700V, 800V, 900V) of the battery pack during charging / discharging. However, in actual charging / discharging operation, since the voltage value of the battery pack is continuous and constantly changing, the actual charge / discharge efficiency table should provide more voltage values, such as 698V, 699V, 700V, 701V, 702V, ..., 800V, 801V, ... , and the smaller the scale interval between adjacent voltage values, the better. For example, 700V, 701V, ... The table uses voltage values ​​of 0.1V, 700.2V, ..., 701V to allow for direct lookup of the battery pack voltage, the corresponding maximum charge / discharge efficiency of the energy storage converter, and the ratio of the required power to the rated power during charging / discharging. For example, when the collected voltage values ​​are 710V, 715V, 720.02V, and 745.37V, these values ​​are recorded in the charge / discharge efficiency table. Therefore, the table can be directly consulted to obtain the corresponding maximum charge / discharge efficiency and the ratio of the required power to the rated power during charging / discharging. Furthermore, even if the maximum charge / discharge efficiency and the ratio of the required power to the rated power for the collected voltage values ​​cannot be directly obtained from the charge / discharge efficiency table, the larger voltage range and smaller voltage division values ​​in the charge / discharge efficiency table can provide more accurate data when using interpolation.

[0044] Table 1. Charge / Discharge Efficiency of a Certain Type of Energy Storage Converter

[0045]

[0046]

[0047] Step 2: After receiving the charging / discharging command from the background, the communication module sends the charging / discharging command to the energy storage converter. After receiving the charging / discharging command, the energy storage converter collects the initial voltage value of the battery pack to be charged / discharged through the voltage sensor. The query module queries the charging / discharging efficiency table to obtain the highest charging / discharging efficiency corresponding to the initial voltage value, and queries the charging / discharging efficiency table again to obtain the ratio of the power required by the energy storage converter to the rated power when charging / discharging at the highest charging / discharging efficiency.

[0048] Step 3: The calculation module calculates the initial power required for the energy storage converter to start charging / discharging based on the ratio of actual power to rated power. The energy storage converter then starts charging / discharging the battery pack using the calculated initial power.

[0049] Step 4: During the charging and discharging process of the battery pack, the voltage sensor monitors the current voltage value of the battery pack in real time or periodically, and obtains the highest charging / discharging efficiency corresponding to the current voltage value according to the charging / discharging efficiency table, and then obtains the ratio of the required power to the rated power according to the highest charging / discharging efficiency.

[0050] In obtaining the highest charge / discharge efficiency corresponding to the current voltage value from the charge / discharge efficiency table, and the ratio of required power to rated power corresponding to the highest charge / discharge efficiency, linear interpolation can be used to obtain the highest charge / discharge efficiency not recorded in the charge / discharge efficiency table for the current voltage value, and the ratio of required power to rated power of the energy storage converter corresponding to the highest charge / discharge efficiency. Since linear interpolation is a simple interpolation method widely used in mathematics, computer graphics, and other fields, and is existing technology, this embodiment does not provide a detailed explanation of how to use linear interpolation to obtain parameter data not recorded in the charge / discharge efficiency table.

[0051] Step 5: The calculation module calculates the required power of the energy storage converter during charging / discharging based on the ratio of the required power to the rated power. At the same time, the adjustment module adjusts it to the actual power of the energy storage converter during charging / discharging, so that the energy storage converter operates at the highest charging / discharging efficiency corresponding to the current voltage value of the object being charged / discharged throughout the charging / discharging process.

[0052] In summary, the energy storage converter charging and discharging control method and system provided by this invention, based on the voltage change characteristics of the charging / discharging object during the charging / discharging process, collects the current voltage value of the charging / discharging object in real time or periodically during the charging / discharging process, obtains the highest charging / discharging efficiency corresponding to the current voltage value according to the charging / discharging efficiency table, and then obtains the ratio of the required power to the rated power according to the highest charging / discharging efficiency; then, calculates the required power of the energy storage converter during charging / discharging based on the obtained ratio of the required power to the rated power, and simultaneously adjusts it to the actual power of the energy storage converter during charging / discharging, so that the energy storage converter operates at the highest charging / discharging efficiency corresponding to the current voltage value of the charging / discharging object throughout the charging / discharging process, thereby improving charging / discharging efficiency and reducing energy loss during the charging / discharging process.

[0053] It should be noted that although the present invention has been disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A method for charge and discharge control of an energy storage converter, characterized by, The method comprises the following steps: S1: obtaining a charge / discharge efficiency table of the energy storage converter, the charge / discharge efficiency table comprising a highest charge / discharge efficiency of the energy storage converter corresponding to different voltage values of a charge / discharge object in a charge / discharge process and a ratio of an actual power to a rated power of the energy storage converter in the charge / discharge process; S2: after the energy storage converter receives a charge / discharge instruction from a background, the energy storage converter starts to charge / discharge the charge / discharge object; S3: during the charge / discharge process, a current voltage value of the charge / discharge object is monitored in real time or periodically, the highest charge / discharge efficiency corresponding to the current voltage value is obtained according to the charge / discharge efficiency table, and a corresponding ratio of a required power to the rated power is obtained according to the highest charge / discharge efficiency; S4: the required power of the energy storage converter in the charge / discharge process is calculated according to the ratio of the required power to the rated power, and the required power is simultaneously adjusted to be the actual power of the energy storage converter in the charge / discharge process, so that the energy storage converter operates at the highest charge / discharge efficiency corresponding to the current voltage value of the charge / discharge object throughout the charge / discharge process.

2. The energy storage inverter charging and discharging control method of claim 1, wherein, Before the energy storage converter starts to charge / discharge the charge / discharge object after receiving the charge / discharge instruction in step S2, the method further comprises the following steps: an initial voltage value of the charge / discharge object is obtained, the highest charge / discharge efficiency corresponding to the initial voltage value is obtained by querying the charge / discharge efficiency table, and the ratio of the actual power to the rated power of the energy storage converter in the charge / discharge process corresponding to the highest charge / discharge efficiency is obtained by querying the charge / discharge efficiency table again; an initial power of the energy storage converter when starting to charge / discharge is calculated according to the ratio of the actual power to the rated power, and the energy storage converter starts to charge / discharge the charge / discharge object at the calculated initial power.

3. The energy storage converter charging and discharging control method of any one of claims 1 or 2, wherein, The initial voltage value and the current voltage value are both obtained by a voltage sensor.

4. The energy storage inverter charging and discharging control method of claim 1, wherein, In step S3, when the highest charge / discharge efficiency corresponding to the current voltage value is obtained according to the charge / discharge efficiency table and the ratio of the actual power to the rated power corresponding to the highest charge / discharge efficiency is obtained according to the highest charge / discharge efficiency, the linear interpolation method is used to obtain the highest charge / discharge efficiency corresponding to the current voltage value and the ratio of the actual power to the rated power corresponding to the highest charge / discharge efficiency, which are not recorded in the charge / discharge efficiency table.

5. The energy storage inverter charging and discharging control method of claim 1, wherein, The charge / discharge efficiency table of the energy storage converter is obtained by a power analyzer through multiple measurements at different voltage points on a direct current side of an energy storage power station system and power points of the energy storage converter.

6. The energy storage inverter charging and discharging control method of claim 1, wherein, The charge / discharge object is a battery pack.

7. An energy storage converter charge-discharge control system, characterized by, The method comprises: a charge / discharge efficiency table in which the highest charge / discharge efficiency of the energy storage converter corresponding to different voltage values of a charge / discharge object in a charge / discharge process and a ratio of a required power to a rated power of the energy storage converter in the charge / discharge process are recorded; a communication module, which is communicatively connected with the energy storage converter and is used to send a received charge / discharge instruction from a background to the energy storage converter, and the energy storage converter charges / discharges the charge / discharge object according to the received charge / discharge instruction; a voltage monitoring module, which is used to monitor a current voltage value of the charge / discharge object in real time or periodically during the charge / discharge process; The query module is in communication or electrical connection with the charge / discharge efficiency table and the voltage monitoring module, respectively, and is configured to query the charge / discharge efficiency table to obtain the highest charge / discharge efficiency corresponding to the current voltage value of the charge / discharge object and the required power-to-rated power ratio corresponding to the highest charge / discharge efficiency; The calculation module is in communication or electrical connection with the query module, and is configured to calculate the required power of the energy storage converter during charge / discharge according to the obtained required power-to-rated power ratio; The adjustment module is in communication or electrical connection with the calculation module and the energy storage converter, respectively, and is configured to simultaneously and synchronously adjust the actual power of the energy storage converter during charge / discharge according to the calculated required power of the energy storage converter during charge / discharge.

8. The energy storage inverter charge and discharge control system of claim 7, wherein, The voltage monitoring module is a voltage sensor.

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