A feedforward control method, device, inverter and medium of an inverter

Abstract

The present application relates to a feedforward control method, device, inverter and medium of an inverter. Among them, the feedforward control method of the inverter includes: obtaining the power of each port in the photovoltaic energy storage system in real time; the power of each port includes the photovoltaic side power, the battery side power and the inverter side power; aiming at the sum of the power of each port being always equal to zero at any moment, determining the current feedforward current based on the operation mode of the inverter; and performing voltage stabilization control on the DC bus voltage of the inverter based on the feedforward current, ensuring the stability of the DC bus of the hybrid inverter in the photovoltaic energy storage system, avoiding the occurrence of under-voltage or over-voltage faults of the bus voltage, and further ensuring the stability of grid-connected and off-grid operation.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic power generation, and in particular, to a feed-forward control method, device, inverter, and medium for an inverter. Background Art

[0002] Solar photovoltaic power generation belongs to clean and renewable energy. Developing and widely applying photovoltaic power generation technology plays an important role in alleviating the shortage of conventional energy and reducing environmental pollution.

[0003] Photovoltaic power generation is the process of converting solar energy into electrical energy. Its output power varies greatly due to environmental factors such as solar radiation intensity and temperature. As a result, the photovoltaic power generation power changes significantly throughout the day. If it cannot respond in a timely manner, when the inverter is operating in parallel with the grid, when the photovoltaic power generation power suddenly increases or decreases, it may cause overvoltage or undervoltage faults in the DC bus, resulting in the inverter shutting down due to a fault; when the inverter is operating off-grid, the disturbance amounts include not only the photovoltaic power generation power but also the load power. If the load power is disturbed rapidly and over a large range, it will also cause the occurrence of undervoltage or overvoltage faults in the bus voltage, resulting in the inverter shutting down due to a fault, thus affecting the stability of the photovoltaic energy storage system operating off-grid. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a feed-forward control method, device, inverter, and medium for an inverter.

[0005] In a first aspect, an embodiment of the present application provides a feed-forward control method for an inverter, which is applied to a photovoltaic energy storage system. The photovoltaic energy storage system includes a photovoltaic module, a storage battery, and an inverter. The inverter is connected to the power grid and a load. The method includes:

[0006] Obtain the power of each port in the photovoltaic energy storage system in real time; the power of each port includes the photovoltaic-side power, the battery-side power, and the inverter-side power;

[0007] Taking the sum of the power of each port at any moment to be always equal to zero as the goal, determine the current feed-forward current based on the operating mode of the inverter;

[0008] Based on the feed-forward current, perform voltage stabilization control on the DC bus voltage of the inverter.

[0009] In one of the embodiments, when the operating mode of the inverter is grid-connected:

[0010] Based on the photovoltaic-side power and the battery-side power, determine the first feed-forward power;

[0011] Based on the first feed-forward power and the grid voltage, determine the first feed-forward current.

[0012] In one embodiment, the step of stabilizing the DC bus voltage of the inverter based on the feedforward current includes:

[0013] Superimpose the first feedforward current on the current output by the DC bus voltage loop on the inverter side as the reference input current value of the inverter current loop;

[0014] Based on the reference input current value of the inverter side current loop, perform voltage stabilization control on the DC bus voltage of the inverter.

[0015] In one embodiment, the step of stabilizing the DC bus voltage of the inverter based on the reference input current of the inverter side current loop includes:

[0016] Adjust the output current of the inverter side current loop to the reference input current value of the inverter side current loop.

[0017] In one embodiment, when the operating mode of the inverter is off-grid:

[0018] Based on the power on the photovoltaic side and the power on the inverter side, determine the second feedforward power;

[0019] Based on the second feedforward power and the battery voltage, determine the second feedforward current.

[0020] In one embodiment, the step of stabilizing the DC bus voltage of the inverter based on the feedforward current includes:

[0021] Superimpose the second feedforward current on the current output by the DC bus voltage loop on the battery side as the reference input current value of the battery current loop;

[0022] Based on the reference input current value of the battery side current loop, perform voltage stabilization control on the DC bus voltage of the inverter.

[0023] In one embodiment, the step of stabilizing the DC bus voltage of the inverter based on the reference input current of the battery side current loop includes:

[0024] Adjust the output current of the battery side current loop to the reference input current of the battery side current loop.

[0025] Second, the embodiment of the present application further provides a feedforward control device for an inverter, which is applied to a photovoltaic energy storage system. The feedforward control device includes:

[0026] An acquisition module, configured to acquire the power of each port in the photovoltaic energy storage system in real time; the power of each port includes the power on the photovoltaic side, the power on the battery side, and the power on the inverter side;

[0027] A determining module, configured to determine a current feed-forward current based on an operating mode of the inverter, with the goal that the sum of the powers of all ports at any moment is always equal to zero.

[0028] A control module, configured to perform a voltage stabilization control on a DC bus voltage of the inverter based on the feed-forward current.

[0029] In a third aspect, an embodiment of the present application further provides an inverter, where the inverter includes the feed-forward control device as described in the second aspect above, and the feed-forward control device is configured to perform a voltage stabilization control on a DC bus voltage of the inverter.

[0030] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. The computer program, when executed by a processor, implements the method as described in the first aspect above.

[0031] The above-mentioned feed-forward control method, device, inverter, and medium of the inverter obtain the powers of all ports in the photovoltaic energy storage system in real time; the powers of all ports include a photovoltaic-side power, a battery-side power, and an inverter-side power; with the goal that the sum of the powers of all ports at any moment is always equal to zero, determine a current feed-forward current based on the operating mode of the inverter; and perform a voltage stabilization control on the DC bus voltage of the inverter based on the feed-forward current, thereby solving the technical problem that when the photovoltaic power or the load power in the photovoltaic energy storage system undergoes a rapid and large-range disturbance, it causes overvoltage and undervoltage faults in the DC bus, resulting in the inverter shutting down due to a fault, thus affecting the stability of the photovoltaic energy storage system in grid-connected and off-grid operations. It ensures the stability of the DC bus of the hybrid inverter in the photovoltaic energy storage system, avoids the occurrence of undervoltage or overvoltage faults of the bus voltage, and guarantees the stability of grid-connected and off-grid operations.

[0032] Details of one or more embodiments of the present application are set forth in the following drawings and description, so as to make other features, objects, and advantages of the present application more concise and understandable. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The illustrative embodiments and descriptions thereof of the present application are used to explain the present application, and do not constitute an improper limitation to the present application. In the drawings:

[0034] Figure 1 is a structural block diagram of a photovoltaic energy storage system in an embodiment;

[0035] Figure 2 is a flowchart of a feed-forward control method of an inverter in an embodiment;

[0036] Figure 3 is a feed-forward control block diagram during grid connection in an embodiment;

[0037] Figure 4 is the feedforward control block diagram during off-grid operation in an embodiment;

[0038] Figure 5 is the structural block diagram of the feedforward control device of the inverter in an embodiment. Detailed implementation manners

[0039] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be described and explained below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments provided in the present application without creative efforts fall within the scope of protection of the present application.

[0040] Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, the present application can be applied to other similar scenarios based on these drawings without creative efforts. In addition, it can also be understood that although the efforts made in this development process may be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacturing or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be understood that the content disclosed in the present application is insufficient.

[0041] Referring to "embodiment" in the present application means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those of ordinary skill in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments without conflict.

[0042] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the ordinary meanings understood by those with ordinary skills in the technical field to which this application belongs. The words such as "a", "an", "one kind", "the" and the like involved in this application do not indicate a quantity limitation and may represent a singular or plural number. The terms "include", "comprise", "have" and any variations thereof involved in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may further include steps or units not listed, or may further include other steps or units inherent to these processes, methods, products or devices. The similar words such as "connect", "be connected", "couple" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "plurality" involved in this application means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, "A and / or B" may represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. The terms "first", "second", "third" and the like involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0043] The feedforward control method of the inverter provided by the embodiment of this application can be applied to, for example, Figure 1 the photovoltaic energy storage system shown in the figure. The photovoltaic energy storage system includes a photovoltaic module 102, a storage battery 104, and an inverter 106, and the inverter 106 is connected to the power grid and the load. Among them, the inverter in the photovoltaic energy storage system is a hybrid inverter, and the hybrid inverter automatically switches to the grid-connected operation mode or the off-grid operation mode according to the power grid state.

[0044] The embodiment of this application provides a feedforward control method of an inverter. Taking the application of this method to Figure 1 the photovoltaic energy storage system in the figure as an example for illustration, as Figure 2 shown in the figure, the method includes the following steps:

[0045] Step 202, obtain the power of each port in the photovoltaic energy storage system in real time; the power of each port includes the photovoltaic side power, the battery side power, and the inverter side power.

[0046] Step 204, with the goal that the sum of the powers of each port at any moment is always equal to zero, determine the current feedforward current based on the operation mode of the inverter.

[0047] Specifically, for a photovoltaic energy storage inverter system, the energy of each port is balanced in real time, and the decoupling and buffering of energy are achieved through the DC bus. Whether in the off-grid mode or the grid-connected mode, it is essentially the control of the energy flow of each port. Considering the positive and negative directions of the power of each port, the sum of the photovoltaic side power (PV power), the battery side power, and the inverter side power (AC power) is always equal to zero.

[0048] Among them, the main difference between the grid-connected mode and the off-grid mode lies in whether it depends on the external power grid. The grid-connected mode depends on the power grid and does not operate during power outages, while the off-grid mode can operate independently without relying on the power grid. The inverter in the photovoltaic energy storage system automatically switches to grid-connected operation or off-grid operation according to the grid status. When operating in grid-connected mode, the DC bus voltage is controlled by the inverter side, and when operating in off-grid mode, the DC bus voltage is controlled by the battery side. Therefore, according to the power of each port in the photovoltaic energy storage system obtained in real time, the sum of the photovoltaic side power, the battery side power, and the inverter side power is always equal to zero, and the magnitude of the current feedforward under the current grid-connected mode or off-grid mode is calculated.

[0049] Step 206, based on the feedforward current, perform voltage stabilization control on the DC bus voltage of the inverter.

[0050] In the above feedforward control method of the inverter, by obtaining the power of each port in the photovoltaic energy storage system in real time; the power of each port includes the photovoltaic side power, the battery side power, and the inverter side power; with the goal that the sum of the power of each port is always equal to zero at any time, based on the operating mode of the inverter, determine the current feedforward current; based on the feedforward current, perform voltage stabilization control on the DC bus voltage of the inverter, which solves the technical problem that when the photovoltaic power or the load power in the photovoltaic energy storage system undergoes rapid and large-scale disturbances, it causes overvoltage and undervoltage faults in the DC bus, resulting in the inverter shutting down due to faults, thus affecting the stability of the photovoltaic energy storage system in grid-connected and off-grid operations, ensuring the stability of the DC bus of the hybrid inverter in the photovoltaic energy storage system, avoiding the occurrence of undervoltage or overvoltage faults in the bus voltage, and further ensuring the stability of grid-connected and off-grid operations.

[0051] It should be noted that the power of the three ports is always equal to zero at any time, AC power + PV power + battery power = 0, which can be transformed into the following two equations:

[0052] AC power = - (PV power + battery power)

[0053] Battery power = - (AC power + PV power)

[0054] Among them, PV power is greater than or equal to 0, AC power is defined as positive from the inverter side to the power grid and negative from the power grid to the inverter, and battery power is defined as negative for charging and positive for discharging.

[0055] In one embodiment, when the operating mode of the inverter is grid-connected, a first feedforward power is determined based on the PV-side power and the battery-side power; a first feedforward current is determined based on the first feedforward power and the grid voltage.

[0056] Specifically, when operating in grid connection, the DC bus voltage is controlled by the inverter side. If the current inverter is in grid-connected operation, the calculation formula for the corresponding first feedforward power (AC power) is as follows:

[0057] AC power = -(PV power + battery power)

[0058] In the formula, PV power is the PV-side power at the current moment obtained, battery power is the battery-side power at the current moment obtained, and AC power is the first feedforward power calculated based on the PV-side power and the battery-side power at the current moment; then, based on the first feedforward power and the grid voltage, a first feedforward current is determined. The calculation formula for the first feedforward current (AC feedforward current) is as follows:

[0059] AC feedforward current = AC power / grid voltage

[0060] In one embodiment, the step of stabilizing the DC bus voltage of the inverter based on the feedforward current includes the following:

[0061] The first feedforward current is superimposed on the current output by the DC bus voltage loop on the inverter side as the reference input current value of the inverter current loop; based on the reference input current value of the inverter side current loop, the DC bus voltage of the inverter is stabilized.

[0062] Specifically, the output current of the inverter side current loop is adjusted to the reference input current value of the inverter side current loop to achieve voltage stabilization control of the DC bus voltage of the inverter.

[0063] Exemplarily, the output current of the inverter side current loop is adjusted to the reference input current value of the inverter side current loop through a current loop PI regulator.

[0064] As Figure 3 shown, a feedforward control block diagram during grid connection is presented. In the figure, I dc_out (s) is the current output by the DC bus voltage loop on the inverter side, i ref (s) is the reference input current of the inverter side current loop; I g (s) is the grid current, V g (s)is the grid voltage, G i (s) is the current loop PI regulator, d(s) is the output of the inverter current loop, G inv (s) is the inverter transfer function, e(s) is the arm output voltage, i inv (s) is the inverter inductance current. When the inverter is operating in parallel with the grid, through AC power = -(PV power + battery power), AC feedforward current = AC power / grid voltage, the feedforward compensation term, i.e., the AC feedforward current, is obtained by real-time calculation. The feedforward compensation term is superimposed on the current I dc_out (s) output from the existing DC bus voltage loop on the inverter side and acts together on the reference input current i ref (s) of the inverter current loop, and the current loop PI regulator G i (s) is used to adjust the output of the inverter current loop d(s) .

[0065] In the above embodiments, if the current inverter is operating in parallel with the grid, the AC feedforward current is superimposed on the output from the existing DC bus voltage loop on the inverter side and acts together on the reference input of the inverter current loop. If the current photovoltaic module and energy storage battery jointly discharge to the grid, when the power of the photovoltaic panel rapidly decreases due to occlusion or weather changes, the AC feedforward current will also rapidly decrease (the feedforward current is positive), and the power input to the grid will also decrease, so that the power on the input and output sides of the DC bus remains balanced. If the response is slow and the inverter side still outputs power at the original level, it will cause a rapid decrease in the bus voltage or even power reverse injection. If the PV power increases, the AC feedforward current will also increase synchronously. The above feedforward control method is also applicable to the working condition where the photovoltaic and the grid charge the battery, and at this time the feedforward current is negative.

[0066] In the above embodiments, by introducing the feedforward quantity of power, this rapid change quantity is advanced to act on the input of the loop, so that the input and output energies at both ends of the DC bus remain balanced, and the bus voltage will not fluctuate greatly. Through feedforward control, the stability of the DC bus of the hybrid inverter in the photovoltaic energy storage system is ensured, and further the stability of the parallel operation is guaranteed.

[0067] In one of the embodiments, when the operating mode of the inverter is off-grid, the second feedforward power is determined based on the photovoltaic side power and the inverter side power; the second feedforward current is determined based on the second feedforward power and the battery voltage.

[0068] Specifically, if the current inverter is operating in off-grid mode and the DC bus voltage during off-grid operation is controlled by the battery side, the calculation formula for the corresponding second feed-forward power (battery power) is as follows:

[0069] Battery power = -(PV power + AC power)

[0070] Wherein, the PV power is the power on the PV side at the current moment, and the AC power is the power on the inverter side at the current moment. It should be noted that if the current inverter is operating in off-grid mode, the power on the inverter side at the current moment is equal to the load power at the current moment. The battery power in the formula is the second feed-forward power calculated based on the power on the PV side and the power on the inverter side at the current moment; then, based on the second feed-forward power and the battery voltage, the second feed-forward current is determined. The calculation formula for the second feed-forward current (battery feed-forward current) is as follows:

[0071] Battery feed-forward current = Battery power / Battery voltage

[0072] In one embodiment, the step of stabilizing the DC bus voltage of the inverter based on the feed-forward current includes the following:

[0073] Superimpose the second feed-forward current and the current output from the DC bus voltage loop on the battery side as the reference input current value for the battery current loop; based on the reference input current value of the battery side current loop, perform voltage stabilization control on the DC bus voltage of the inverter.

[0074] Specifically, by adjusting the output current of the battery side current loop to the reference input current of the battery side current loop, voltage stabilization control of the DC bus voltage of the inverter is achieved.

[0075] Exemplarily, the output current of the inverter side current loop is adjusted to the reference input current value of the inverter side current loop through a PI regulator of the battery current loop.

[0076] As Figure 4 shown, a feed-forward control block diagram during off-grid operation is presented. In the figure, I dc_out (s) is the current output from the DC bus voltage loop on the battery side, i bat_ref (s) is the reference input current of the battery side current loop; G i_bat (s) is the PI regulator of the battery current loop, d(s) is the output of the battery current loop, G bat (s) is the transfer function on the battery side, ebat (s) is the battery voltage. When the inverter is operating in off-grid mode, the battery power = -(PV power + AC power), and the battery feedforward current = battery power / battery voltage. The feedforward compensation term, i.e., the battery feedforward current, is calculated in real time and added to the current output by the DC bus voltage loop on the battery side I dc_out (s) and they act together on the reference input current of the battery-side current loop i ref (s) , and the PI regulator of the battery current loop is used G i_bat (s) to regulate the output of the battery current loop d(s) .

[0077] In the above embodiments, if the current inverter is operating in off-grid mode, the battery feedforward current is added to the existing output of the battery-side bus voltage loop and they act together on the reference input of the battery current loop. When the inverter is operating in off-grid mode, the disturbance quantities include not only the PV power but also the load power (i.e., the inverter AC power). If the load power suddenly changes, according to the battery feedforward power = -(PV power + AC power), when the PV power is greater than the load power, the battery feedforward current becomes negative, that is, it switches to the charging state; when the PV power is less than the load power, the battery feedforward current is positive, that is, it switches to the discharging state. According to the positive and negative of the feedforward current, the charge and discharge states are switched in time to balance the difference between the PV power and the load power of the system in real time. If the charge and discharge current response on the battery side is not timely, when the load suddenly increases, the DC bus voltage may be quickly pulled down, and when the load suddenly decreases, the bus voltage may be instantaneously pulled up to a very high level. The same is true for the change of the PV power.

[0078] In the above embodiments, the magnitudes of the PV power and the AC power are calculated in real time, and the feedforward quantity of the power is introduced to quickly sense their changes. The changing power is applied to the battery side, and the battery balances the system power in real time. When the load suddenly increases or decreases or the PV power changes, the charge and discharge power of the battery will also change quickly, ensuring the stability of the power on the DC bus and preventing faults such as a decrease (undervoltage fault) or an increase (overvoltage fault) in the bus voltage due to a sudden increase or decrease in the load. Through feedforward control, the stability of the DC bus of the hybrid inverter in the photovoltaic energy storage system is ensured, and thus the stability of the off-grid operation is guaranteed.

[0079] According to the operating mode of the current inverter, the present application calculates the corresponding feed-forward power in real time, further calculates the feed-forward current, and applies it in advance to the input of the loop, so as to keep the input and output energy at both ends of the DC bus balanced and prevent the bus voltage from fluctuating significantly. Ensure that when the PV power or load power in the photovoltaic energy storage system undergoes rapid and large-scale disturbances, the DC bus voltage is always maintained stable, avoiding the occurrence of under-voltage or over-voltage faults of the bus voltage, and ensuring the stability of the DC bus of the photovoltaic energy storage hybrid inverter through feed-forward control, thereby ensuring the stability of grid-connected and off-grid operation.

[0080] Based on the same inventive concept, an embodiment of the present application further provides a feed-forward control device for an inverter, which is applied to a photovoltaic energy storage system. The photovoltaic energy storage system includes a photovoltaic module, an energy storage battery, and an inverter. The inverter is connected to the power grid and a load, as Figure 5 shown. The feed-forward control device includes an acquisition module 10, a determination module 20, and a control module 30, where:

[0081] The acquisition module 10 is configured to acquire the power of each port in the photovoltaic energy storage system in real time; the power of each port includes the photovoltaic-side power, the battery-side power, and the inverter-side power;

[0082] The determination module 20 is configured to determine the current feed-forward current based on the operating mode of the inverter with the goal that the sum of the powers of each port at any moment is always equal to zero;

[0083] The control module 30 is configured to perform voltage stabilization control on the DC bus voltage of the inverter based on the feed-forward current.

[0084] In one embodiment, the determination module 20 is further configured to, when the operating mode of the inverter is grid-connected, determine a first feed-forward power based on the photovoltaic-side power and the battery-side power; and determine a first feed-forward current based on the first feed-forward power and the grid voltage.

[0085] In one embodiment, the control module 30 is further configured to superimpose the first feed-forward current and the current output by the DC bus voltage loop on the inverter side as the reference input current value of the inverter current loop; and perform voltage stabilization control on the DC bus voltage of the inverter based on the reference input current value of the inverter current loop.

[0086] In one embodiment, the control module 30 is further configured to adjust the output current of the inverter current loop to the reference input current value of the inverter current loop.

[0087] In one embodiment, the determining module 20 is further configured to, when the operating mode of the inverter is off-grid, determine a second feedforward power based on the PV-side power and the inverter-side power; and determine a second feedforward current based on the second feedforward power and the battery voltage.

[0088] In one embodiment, the control module 30 is further configured to superimpose the second feedforward current on the current output by the battery-side DC bus voltage loop as the reference input current value of the battery current loop; and perform a voltage stabilization control on the DC bus voltage of the inverter based on the reference input current value of the battery-side current loop.

[0089] In one embodiment, the control module 30 is further configured to adjust the output current of the battery-side current loop to the reference input current of the battery-side current loop.

[0090] Each module in the above feedforward control device of the inverter can be implemented in whole or in part by software, hardware, and their combination. The above modules can be embedded in the processor in the computer device in the form of hardware or independent of the processor, or stored in the memory in the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0091] Based on the same inventive concept, an embodiment of the present application further provides an inverter, which includes the feedforward control device as described in the above embodiment, and the feedforward control device is used to perform voltage stabilization control on the DC bus voltage of the inverter.

[0092] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0093] Step 202, obtain the power of each port in the PV energy storage system in real time; the power of each port includes the PV-side power, the battery-side power, and the inverter-side power;

[0094] Step 204, with the goal that the sum of the powers of each port at any moment is always equal to zero, determine the current feedforward current based on the operating mode of the inverter;

[0095] Step 206, perform voltage stabilization control on the DC bus voltage of the inverter based on the feedforward current.

[0096] In one embodiment, when the operating mode of the inverter is grid-connected, the processor further implements the following steps when executing the computer program:

[0097] Determine a first feedforward power based on the PV-side power and the battery-side power;

[0098] Determine a first feedforward current based on the first feedforward power and the grid voltage.

[0099] In one embodiment, when the processor executes the computer program, the following steps are further implemented:

[0100] Superimpose the first feedforward current on the current output by the DC bus voltage loop on the inverter side as the reference input current value of the inverter current loop;

[0101] Based on the reference input current value of the inverter side current loop, perform voltage stabilization control on the DC bus voltage of the inverter.

[0102] In one embodiment, when the processor executes the computer program, the following steps are further implemented:

[0103] Adjust the output current of the inverter side current loop to the reference input current value of the inverter side current loop.

[0104] In one embodiment, when the operating mode of the inverter is off-grid, when the processor executes the computer program, the following steps are further implemented:

[0105] Determine a second feedforward power based on the photovoltaic side power and the inverter side power;

[0106] Determine a second feedforward current based on the second feedforward power and the battery voltage.

[0107] In one embodiment, when the processor executes the computer program, the following steps are further implemented:

[0108] Superimpose the second feedforward current on the current output by the DC bus voltage loop on the battery side as the reference input current value of the battery current loop;

[0109] Based on the reference input current value of the battery side current loop, perform voltage stabilization control on the DC bus voltage of the inverter.

[0110] In one embodiment, when the processor executes the computer program, the following steps are further implemented:

[0111] Adjust the output current of the battery side current loop to the reference input current of the battery side current loop.

[0112] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0113] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0114] The above embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A feedforward control method for an inverter, which is applied to a photovoltaic energy storage system. The photovoltaic energy storage system includes a photovoltaic module, an energy storage battery, and an inverter. The inverter is connected to the power grid and a load, and is characterized in that, The method includes: Obtaining the power of each port in the photovoltaic energy storage system in real time; the power of each port includes the photovoltaic side power, the battery side power, and the inverter side power; Taking the sum of the powers of each port at any time being always equal to zero as the goal, and determining the current feed-forward current based on the operating mode of the inverter; Based on the feed-forward current, performing voltage stabilization control on the DC bus voltage of the inverter; When the operating mode of the inverter is grid-connected: Determining a first feed-forward power based on the photovoltaic side power and the battery side power; Determining a first feed-forward current based on the first feed-forward power and the grid voltage; When the operating mode of the inverter is off-grid: Determining a second feed-forward power based on the photovoltaic side power and the inverter side power; Determining a second feed-forward current based on the second feed-forward power and the battery voltage.

2. The method according to claim 1, wherein The performing voltage stabilization control on the DC bus voltage of the inverter based on the feed-forward current includes: Superimposing the first feed-forward current and the current output by the DC bus voltage loop on the inverter side as the reference input current value of the inverter current loop; Based on the reference input current value of the inverter side current loop, performing voltage stabilization control on the DC bus voltage of the inverter.

3. The method according to claim 2, characterized in that, The performing voltage stabilization control on the DC bus voltage of the inverter based on the reference input current of the inverter side current loop includes: Adjusting the output current of the inverter side current loop to the reference input current value of the inverter side current loop.

4. The method according to claim 1, wherein The performing voltage stabilization control on the DC bus voltage of the inverter based on the feed-forward current includes: Superimposing the second feed-forward current and the current output by the DC bus voltage loop on the battery side as the reference input current value of the battery current loop; Based on the reference input current value of the battery side current loop, performing voltage stabilization control on the DC bus voltage of the inverter.

5. The method according to claim 4, characterized in that, The performing voltage stabilization control on the DC bus voltage of the inverter based on the reference input current of the battery side current loop includes: Adjusting the output current of the battery side current loop to the reference input current of the battery side current loop.

6. A feedforward control device for an inverter, which is applied to a photovoltaic energy storage system, is characterized in that The feed-forward control device includes: An acquisition module for obtaining the power of each port in the photovoltaic energy storage system in real time; the power of each port includes the photovoltaic side power, the battery side power, and the inverter side power; A determination module for taking the sum of the powers of each port at any time being always equal to zero as the goal, and determining the current feed-forward current based on the operating mode of the inverter; when the operating mode of the inverter is grid-connected: determining a first feed-forward power based on the photovoltaic side power and the battery side power; determining a first feed-forward current based on the first feed-forward power and the grid voltage; when the operating mode of the inverter is off-grid: determining a second feed-forward power based on the photovoltaic side power and the inverter side power; determining a second feed-forward current based on the second feed-forward power and the battery voltage; A control module for performing voltage stabilization control on the DC bus voltage of the inverter based on the feed-forward current.

7. An inverter, characterized in that, The inverter includes the feed-forward control device as claimed in claim 6, and the feed-forward control device is used for performing voltage stabilization control on the DC bus voltage of the inverter.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method according to any one of claims 1 to 5.

Images