A control method, controller and computer-readable storage medium for an energy storage system

Abstract

The present invention discloses a control method, a controller, and a computer-readable storage medium for an energy storage system, wherein the energy storage system includes an energy storage component, a DC-DC device, a DC bus, and a DC-AC device coupled in sequence; the DC-DC device includes a power inductor element, and the DC-AC device is connected to a power grid; when the power grid charges the energy storage component, the control method includes the following steps: obtaining a first electrical parameter value of the power inductor element, the first electrical parameter value being used to characterize the load condition of the DC-DC device; when the first electrical parameter value exceeds a first preset threshold, increasing the voltage of the DC bus according to the first electrical parameter value to reduce the peak-to-peak current ripple of the power inductor element; the control method can reduce the peak-to-peak current ripple of the power inductor element in the DC-DC device, so that the energy storage system meets the energy storage standard requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage systems, and in particular to a control method, a controller, and a computer-readable storage medium for an energy storage system. Background Art

[0002] Energy storage systems typically include a DC / DC device coupled to an energy storage component. The DC / DC device converts the voltage and then transmits the current to the DC / AC device via the DC bus, which then transmits it to the grid or load. The DC / DC device includes a power inductor. Energy storage industry standards require that the peak-to-peak current ripple of the power inductor in a DC / DC device cannot exceed 10%. This peak-to-peak current ripple is directly related to the inductance of the power inductor. However, in actual applications, due to factors such as price and size, the inductance of the power inductor cannot reach an excessively large value. Therefore, when the current flowing through the power inductor is large, the peak-to-peak current ripple in the power inductor is excessive, exceeding the standard requirements. Summary of the Invention

[0003] The object of the present invention is to overcome the above-mentioned defects or problems existing in the background technology and provide a control method, controller and computer-readable storage medium for an energy storage system. The control method can reduce the peak-to-peak current ripple of the power inductor element in the DC-DC device, so that the energy storage system meets the energy storage standard requirements.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A control method for an energy storage system, the energy storage system comprising a sequentially coupled energy storage component, a DC-DC device, a DC bus, and a DC-AC device; the DC-DC device comprising a power inductor element, and the DC-AC device being connected to a power grid; the control method comprising the following steps when the power grid charges the energy storage component: obtaining a first electrical parameter value of the power inductor element, the first electrical parameter value being used to characterize a load condition of the DC-DC device; and when the first electrical parameter value exceeds a first preset threshold, increasing the voltage of the DC bus according to the first electrical parameter value to reduce peak-to-peak current ripple of the power inductor element.

[0006] Furthermore, the first preset threshold is determined by multiplying the full-load electrical parameter of the DC-DC device by a preset load factor, and the preset load factor is between 0.6 and 0.8.

[0007] Furthermore, the first electrical parameter value is the current value of the power inductor element, and the full-load electrical parameter is the full-load current of the DC-DC device.

[0008] Furthermore, the DC-DC device is provided with a bus voltage control loop for controlling the voltage of the DC bus; increasing the voltage of the DC bus according to the first electrical parameter value includes: determining a bus voltage set value according to the first electrical parameter value; determining a set value of the bus voltage control loop according to the determined bus voltage set value, so as to increase the voltage of the DC bus through the bus voltage control loop.

[0009] Furthermore, determining a bus voltage set value based on the first electrical parameter value includes: determining a bus voltage set value corresponding to the first electrical parameter value based on a preset UI curve; wherein the preset UI curve is used to characterize the one-to-one correspondence between the current value of the power inductor element and the bus voltage set value, and the current value of the power inductor element and the bus voltage set value are in direct proportion.

[0010] In addition, the present invention also provides a controller, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the energy storage system control method as described above when executing the computer program.

[0011] In addition, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the energy storage system control method as described in any one of the above items are implemented.

[0012] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0013] This energy storage system control method is particularly applicable to the process of charging energy storage components by the power grid. By obtaining a first electrical parameter value of a power inductor element in a DC-DC device in real time and determining that the first electrical parameter value exceeds a first preset threshold, the voltage of a DC bus connected to the DC-DC device is increased. As the input voltage of the DC-DC device increases, the voltage amplitude occupied by its own peak-to-peak voltage ripple decreases. Because the output voltage of the DC-DC device remains unchanged compared to normal conditions when the energy storage component is charging, the average current value of the power inductor element also remains essentially unchanged. At the same time, the current value of the power inductor element is affected by the input voltage of the DC-DC device. Therefore, the current amplitude occupied by the peak-to-peak current ripple in the power inductor element is reduced, thereby meeting the requirements of energy storage industry standards.

[0014] Among them, the amplitude of the increase in the input voltage of the DC-DC device, that is, the corresponding bus voltage set value is determined by a preset UI curve. The bus voltage set value corresponds to the first electrical parameter value, that is, the current value of the power inductor element. When the current value of the power inductor element is small, the corresponding bus voltage set value is also small, and when the current value of the power inductor element is large, the corresponding bus voltage set value is also large, thereby increasing the input voltage of the DC-DC device and reducing the current amplitude occupied by the peak-to-peak ripple of the power inductor element current. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic diagram of an embodiment of the electrical connection of an energy storage inversion system provided by the present invention. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] In the claims, description and drawings of the present invention, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" is for the purpose of distinguishing different objects rather than for describing a specific order.

[0019] In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise expressly defined, directional words such as the terms "center", "transverse", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the specific scope of protection of the present invention.

[0020] In the claims, description and above-mentioned drawings of the present invention, unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two parties, that is, including non-detachable fixed connection, detachable fixed connection, integral connection and fixed connection through other devices or elements.

[0021] In the claims, description and drawings of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0022] See also Figure 1 , Figure 1 A schematic diagram of an embodiment of the electrical connection of an energy storage system provided by the present invention is shown. The energy storage system mainly includes an energy storage component, a DC-DC device, a DC bus and a DC-AC device coupled in sequence, wherein the DC-DC device includes a power inductor element, and the DC-AC device has two output ends, one of which is connected to the grid end and the other is connected to the load end.

[0023] An embodiment of the present invention provides a control method for an energy storage system. The control method is used to reduce the peak-to-peak current ripple of a power inductor element in a DC-DC device when the power grid charges the energy storage component. The control method mainly includes the following steps:

[0024] Obtain a first electrical parameter value of the power inductor element, where the first electrical parameter value is used to characterize the load condition of the DC-DC device; when the first electrical parameter value exceeds a first preset threshold, increase the voltage of the DC bus according to the first electrical parameter value to reduce the peak-to-peak current ripple of the power inductor element.

[0025] The first preset threshold is determined by multiplying the full-load electrical parameter of the DC-DC device by a preset load factor. The preset load factor is between 0.6 and 0.8. In this embodiment, the preset load factor is set to 0.7.

[0026] In addition, the first electrical parameter value is the current value of the power inductor element, and the full-load electrical parameter is the full-load current of the DC-DC device.

[0027] That is, in this embodiment, the current value of the inductor element in the DC-DC device is detected and obtained in real time. After the current value exceeds 0.7 times the full-load current value of the DC-DC device, the voltage of the DC bus is increased to reduce the peak-to-peak current ripple of the power inductor element.

[0028] Among them, a bus voltage control loop for controlling the DC bus voltage is provided in the DC-DC device. When the DC bus voltage needs to be increased, a bus voltage set value is first determined based on the first electrical parameter value, that is, the current value of the inductor element in the DC-DC device. Then, a set value of the bus voltage control loop is determined based on the bus voltage set value, so as to increase the DC bus voltage through the bus voltage control loop.

[0029] Specifically, the bus voltage set value is determined based on the correspondence between a preset UI curve and the first electrical parameter value. The UI curve is used to characterize the one-to-one correspondence between the current value of the power inductor element and the bus voltage set value, and the current value of the power inductor element and the bus voltage set value are in a positive proportional relationship.

[0030] The UI curve can be determined through experiments or theoretical calculations based on actual conditions. It can be in the form of a linear relationship. When it is a linear relationship, the slope is positive. It should also be noted that the bus voltage set value and the corresponding power inductor current value must meet the requirement of avoiding overmodulation. That is, the slope of the linear relationship should not be too large to ensure charging safety.

[0031] The energy storage system control method provided in this embodiment is particularly applicable to the process of charging an energy storage component by a power grid. By obtaining a first electrical parameter value of a power inductor element in a DC-DC device in real time and determining that the first electrical parameter value exceeds a first preset threshold, the voltage of the DC bus connected to the DC-DC device is increased. As the input voltage of the DC-DC device increases, the voltage amplitude occupied by its own peak-to-peak voltage ripple decreases. Because the output voltage of the DC-DC device remains unchanged compared to normal conditions when the energy storage component is charging, the average current value of the power inductor element also remains essentially unchanged. At the same time, the current value of the power inductor element is affected by the input voltage of the DC-DC device. Therefore, the peak-to-peak current ripple in the power inductor element reduces the current amplitude, thereby meeting the requirements of energy storage industry standards.

[0032] Among them, the amplitude of the increase in the input voltage of the DC-DC device, that is, the corresponding bus voltage set value is determined by a preset UI curve. The bus voltage set value corresponds to the first electrical parameter value, that is, the current value of the power inductor element. When the current value of the power inductor element is small, the corresponding bus voltage set value is also small, and when the current value of the power inductor element is large, the corresponding bus voltage set value is also large, thereby increasing the input voltage of the DC-DC device and reducing the current amplitude occupied by the peak-to-peak ripple of the power inductor element current.

[0033] In addition, based on the above method, this embodiment also discloses a controller, which includes at least one processor and memory, and a computer program stored in the memory and runable on the processor, and may also include a display screen, a communication interface, and a bus. The processor, display screen, memory, and communication interface can communicate with each other via the bus. The display screen is configured to display a user guide interface preset in the initial setting mode. The communication interface can transmit information. The processor can call the logic instructions in the memory to execute the method in the above embodiment.

[0034] In addition, the logical instructions in the above-mentioned memory can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. The memory, as a computer-readable storage medium, can be configured to store software programs, computer executable programs, such as program instructions or modules corresponding to the methods in the embodiments of the present disclosure. The processor executes the functional application and data processing by running the software programs, instructions or modules stored in the memory, that is, implementing the methods in the above-mentioned embodiments.

[0035] The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system and at least one application required for a function; the data storage area may store data created based on the use of the terminal device, etc. In addition, the memory may include high-speed random access memory and may also include non-volatile memory. For example, a variety of media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, may also be a transient storage medium.

[0036] The above description and embodiments are intended to explain the scope of protection of the present invention, but do not constitute a limitation thereto. Modifications, equivalent substitutions, or other improvements to the embodiments of the present invention or portions thereof that can be obtained by a person of ordinary skill in the art through logical analysis, reasoning, or limited experimentation based on the teachings of the present invention or the above embodiments, combined with common knowledge, ordinary technical knowledge in the field, and / or prior art, should all be included within the scope of protection of the present invention.

Claims

1. A control method for an energy storage system, wherein the energy storage system comprises an energy storage component, a DC-DC device, a DC bus, and a DC-AC device coupled in sequence; the DC-DC device comprises a power inductor element, and the DC-AC device is connected to a power grid; wherein: The control method comprises the following steps when the power grid charges the energy storage component: Acquiring a first electrical parameter value of the power inductor element, where the first electrical parameter value is used to characterize a load condition of the DC-DC device; When the first electrical parameter value exceeds a first preset threshold, increasing the voltage of the DC bus according to the first electrical parameter value to reduce the peak-to-peak current ripple of the power inductor element; The first preset threshold is determined by multiplying the full-load electrical parameter of the DC-DC device by a preset load factor, wherein the preset load factor is between 0.6 and 0.8; The first electrical parameter value is the current value of the power inductor element, and the full-load electrical parameter is the full-load current of the DC-DC device.

2. The control method of an energy storage system according to claim 1, wherein: The DC-DC device is provided with a bus voltage control loop for controlling the voltage of the DC bus; Increasing the voltage of the DC bus according to the first electrical parameter value includes: Determining a bus voltage given value according to the first electrical parameter value; A set value of the bus voltage control loop is determined according to the determined bus voltage set value, so as to increase the voltage of the DC bus through the bus voltage control loop.

3. The control method of an energy storage system according to claim 2, wherein: Determining a bus voltage given value according to the first electrical parameter value includes: The bus voltage set value corresponding to the first electrical parameter value is determined according to a preset UI curve; wherein the preset UI curve is used to characterize the one-to-one correspondence between the current value of the power inductor element and the bus voltage set value, and the current value of the power inductor element and the bus voltage set value are in a positive proportional relationship.

4. A controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the energy storage system control method as described in any one of claims 1 to 3 are implemented.

5. A computer-readable storage medium storing a computer program, wherein: When the computer program is executed by a processor, the steps of the energy storage system control method as described in any one of claims 1 to 3 are implemented.

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