Control method, device, equipment, medium and product of dual active bridge inverter

Abstract

The present application relates to a control method, apparatus, device, medium, and product for a dual-active bridge inverter. The method comprises: obtaining an input voltage of the dual-active bridge inverter; determining a current adjustment value for the dual-active bridge inverter based on fluctuations in the input voltage; obtaining a current reference value, determining control parameters based on the updated current reference value and the current adjustment value, and using the control parameters to control the operation of the dual-active bridge inverter and adjust the grid-connected current output from the grid-connected port of the dual-active bridge inverter. This method can stabilize voltage and reduce grid-connected current distortion.

Description

Technical Field

[0001] The present application relates to the field of power grid technology, and in particular to a control method, device, equipment, medium and product for a dual active bridge inverter. Background Art

[0002] With the development of new energy technologies, wind power generation systems have also made great progress. In wind power generation systems, inverters feed the voltage output by the generator into the power grid.

[0003] Currently, dual-active bridge microinverters can be used as loads for low-voltage bus capacitors in wind power systems. In this case, the inverter is required to be able to stabilize the voltage of the low-voltage bus capacitor. The current output by the dual-active bridge microinverter is fed into the grid and needs to be synchronized with the grid to meet the phase requirements. The output current needs to be at the same frequency and phase as the grid current. However, the energy stored in the low-voltage bus capacitor is limited. Therefore, changes in the instantaneous power output of the inverter will directly affect the voltage on the low-voltage bus capacitor. Therefore, when the inverter is operating normally, a large ripple will be introduced on the low-voltage bus capacitor. In existing wind power generation systems, the control strategy adopts a conventional dual-loop control strategy. Under this control strategy, in order to keep the DC input voltage stable at the reference point, the output current needs to be adjusted frequently within a single grid cycle, resulting in large distortion of the current connected to the grid. Summary of the Invention

[0004] Based on this, it is necessary to provide a control method, device, equipment, medium and product for a dual active bridge inverter that can stabilize voltage and reduce grid current distortion to address the above technical problems.

[0005] In a first aspect, the present application provides a control method for a dual active bridge inverter, the method comprising:

[0006] Obtain the input voltage of the dual active bridge inverter;

[0007] Determine the current adjustment of the dual active bridge inverter according to the fluctuation of the input voltage;

[0008] A current reference value is obtained, a control parameter is determined according to the updated current reference value and the current adjustment amount, and the control parameter is used to control the operation of the dual active bridge inverter to adjust the grid-connected current output from the grid-connected port of the dual active bridge inverter.

[0009] In one embodiment, the method further comprises:

[0010] After every half power grid cycle, the effective value of the current is calculated according to the pre-established first corresponding relationship between the instantaneous value and the effective value and the instantaneous value of the current;

[0011] The current reference value is calculated according to the pre-established second corresponding relationship between the effective value and the reference value and the current effective value, and the calculated current reference value is determined as the current reference value of the current half grid cycle.

[0012] In one embodiment, determining the control parameter based on the updated current reference value and the current adjustment amount includes:

[0013] Calculate the current peak value of the current control cycle according to the updated current peak value and current adjustment amount, and calculate the current instantaneous value according to the current peak value;

[0014] A control parameter is determined according to the instantaneous value of the current; wherein the control parameter includes at least one of an inner phase shift angle and an outer phase shift angle.

[0015] In one embodiment, determining a current adjustment amount of a dual active bridge inverter according to fluctuations in an input voltage includes:

[0016] When the fluctuation of the input voltage meets the adjustment trigger condition, the voltage excess is calculated based on the input voltage and the preset voltage range;

[0017] The voltage excess is converted according to a pre-established voltage-current conversion relationship to obtain a current adjustment amount of the dual active bridge inverter.

[0018] In one embodiment, the method further comprises:

[0019] In the case where the input voltage exceeds the preset voltage range, it is determined that the fluctuation of the input voltage meets the adjustment trigger condition.

[0020] In one embodiment, the method further comprises:

[0021] Calculate the voltage error according to the input voltage and the reference voltage;

[0022] Calculate the error range based on the preset voltage range and the reference voltage;

[0023] When the voltage error exceeds the error range, it is determined that the fluctuation of the input voltage meets the adjustment trigger condition.

[0024] In one embodiment, the method further comprises:

[0025] When the dual-active bridge inverter is in a preset working state, obtaining a voltage fluctuation range of the low-voltage bus capacitor; wherein the preset working state includes that the input device of the dual-active bridge inverter is a constant-voltage DC source, and the power of the constant-voltage DC source is greater than the peak output power of the dual-active bridge inverter;

[0026] The preset voltage range is determined according to the voltage fluctuation range of the low-voltage bus capacitor.

[0027] In a second aspect, the present application further provides a control device for a dual active bridge inverter, the device comprising:

[0028] An input voltage acquisition module, used to obtain the input voltage of the dual active bridge inverter;

[0029] An adjustment amount determination module, used to determine the current adjustment amount of the dual active bridge inverter according to the fluctuation of the input voltage;

[0030] The control module is used to obtain a current reference value, determine a control parameter according to the updated current reference value and the current adjustment amount, and use the control parameter to control the operation of the dual active bridge inverter and adjust the grid-connected current output by the dual active bridge inverter from the grid-connected port.

[0031] In a third aspect, the present application further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0032] Obtain the input voltage of the dual active bridge inverter;

[0033] Determine the current adjustment of the dual active bridge inverter according to the fluctuation of the input voltage;

[0034] A current reference value is obtained, a control parameter is determined according to the updated current reference value and the current adjustment amount, and the control parameter is used to control the operation of the dual active bridge inverter to adjust the grid-connected current output from the grid-connected port of the dual active bridge inverter.

[0035] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the following steps are implemented:

[0036] Obtain the input voltage of the dual active bridge inverter;

[0037] Determine the current adjustment of the dual active bridge inverter according to the fluctuation of the input voltage;

[0038] A current reference value is obtained, a control parameter is determined according to the updated current reference value and the current adjustment amount, and the control parameter is used to control the operation of the dual active bridge inverter to adjust the grid-connected current output from the grid-connected port of the dual active bridge inverter.

[0039] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the following steps:

[0040] Obtain the input voltage of the dual active bridge inverter;

[0041] Determine the current adjustment of the dual active bridge inverter according to the fluctuation of the input voltage;

[0042] A current reference value is obtained, a control parameter is determined according to the updated current reference value and the current adjustment amount, and the control parameter is used to control the operation of the dual active bridge inverter to adjust the grid-connected current output from the grid-connected port of the dual active bridge inverter.

[0043] The control method, device, equipment, medium, and product for the dual-active bridge inverter described above obtain the input voltage of the dual-active bridge inverter; determine the current adjustment amount of the dual-active bridge inverter based on the fluctuation of the input voltage; obtain a current reference value, determine control parameters based on the updated current reference value and the current adjustment amount, and use the control parameters to control the operation of the dual-active bridge inverter and adjust the grid-connected current output from the grid-connected port of the dual-active bridge inverter. The embodiments of the present application adjust the grid-connected current output by the dual-active bridge inverter based on the fluctuation of the input voltage of the dual-active bridge inverter, which not only achieves the effect of stabilizing the voltage but also reduces the distortion of the grid-connected current. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1a is a structural schematic diagram of a wind power generation system in one embodiment;

[0046] Figure 1b 1 is a schematic structural diagram of a dual active bridge inverter in one embodiment;

[0047] Figure 2 1 is a flow chart of a control method for a dual active bridge inverter in one embodiment;

[0048] Figure 3 A schematic flow chart of a step of determining control parameters in one embodiment;

[0049] Figure 4 1 is a flow chart of a step of updating a current reference value in one embodiment;

[0050] Figure 5 FIG1 is a flow chart of the steps of determining the current adjustment amount in one embodiment;

[0051] Figure 6 Schematic diagram of a flow chart of determining whether an adjustment trigger condition is met in one embodiment;

[0052] Figure 7 Schematic diagram of a flow chart of the step of determining a preset voltage range in one embodiment;

[0053] Figure 8 is a flow chart of a control method for a dual active bridge inverter in another embodiment;

[0054] Figure 9 is a structural block diagram of a control device for a dual active bridge inverter in one embodiment;

[0055] Figure 10 FIG. 1 is a diagram showing the internal structure of an electronic device in one embodiment. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0057] First, before specifically introducing the technical solutions of the embodiments of the present application, the technical background or technical evolution context on which the embodiments of the present application are based is introduced. With the development of new energy technologies, wind power generation systems have also made great progress. Figure 1a A small direct-drive wind power generation system shown uses a rectifier bridge to rectify the current output by the generator stator. Changes in wind speed will cause DC side voltage fluctuations. The grid-side converter is used to stabilize the voltage and feed it into the grid.

[0058] The grid-side converter can be used as Figure 1b The dual-active bridge microinverter shown in the figure acts as a load for the low-voltage bus capacitor in a wind power system. In this case, the inverter must be able to stabilize the voltage of the low-voltage bus capacitor. The output current of the dual-active bridge microinverter is fed into the grid and needs to be synchronized with the grid to meet phase requirements. The output current must be in the same frequency and phase as the grid current.

[0059] However, the energy stored in the low-voltage bus capacitor is limited. Therefore, changes in the inverter's instantaneous output power directly affect the voltage on the low-voltage bus capacitor, introducing significant ripple on the low-voltage bus capacitor during normal inverter operation. Existing wind power generation systems employ a conventional dual-loop control strategy. To maintain the DC input voltage at a stable reference point, this strategy requires frequent adjustments to the output current within a single grid cycle, resulting in significant distortion in the current fed into the grid.

[0060] In response to the above problems, an embodiment of the present application provides a control method for a dual-active bridge inverter. According to the fluctuation of the input voltage of the dual-active bridge inverter, the grid-connected current output by the dual-active bridge inverter is adjusted, which not only achieves the effect of stabilizing the voltage, but also reduces the distortion of the grid-connected current.

[0061] In an exemplary embodiment, Figure 2 As shown, a control method for a dual active bridge inverter is provided, and the method is applied to Figure 1a The following steps are described using the grid-side converter, i.e., the dual active bridge inverter, in the wind power generation system as an example:

[0062] Step 101: Obtain the input voltage of the dual active bridge inverter.

[0063] The dual-active bridge inverter acts as a load for the low-voltage bus capacitor. Therefore, the input voltage of the dual-active bridge inverter can be obtained by detecting the voltage of the low-voltage bus capacitor. Alternatively, a voltage sensor can be provided to collect the input voltage of the dual-active bridge inverter.

[0064] It should be noted that the method for obtaining the input voltage is not limited to the above example, and other methods may also be used.

[0065] Step 102: Determine the current adjustment amount of the dual active bridge inverter according to the fluctuation of the input voltage.

[0066] A correspondence between the input voltage fluctuation and the current adjustment is pre-established. After obtaining the input voltage, the input voltage fluctuation can be determined based on the input voltage and a preset reference voltage. Then, the current adjustment is calculated based on the correspondence and the input voltage fluctuation.

[0067] For example, the input voltage fluctuation ΔU and the current adjustment ΔI gmref The corresponding relationship between them is ΔU=K*ΔI gmref , assuming the input voltage is U1 and the reference voltage is Uref, the fluctuation of the input voltage ΔU=U1-Uref=K*ΔI gmref , the current adjustment ΔI can be calculated gmref .

[0068] Step 103 : obtaining a current reference value, determining a control parameter according to the updated current reference value and the current adjustment amount, and controlling the operation of the dual active bridge inverter using the control parameter to adjust the grid-connected current outputted from the grid-connected port of the dual active bridge inverter.

[0069] The current reference value is updated every half grid cycle based on the instantaneous current value. After the current adjustment is determined, the current reference value determined in the previous half grid cycle is retrieved. The current peak value for the current control cycle is calculated based on the updated current adjustment and the current reference value. The control parameters are then determined based on the pre-established correspondence between the current peak value and the control parameter and the current peak value for the current control cycle.

[0070] The dual active bridge inverter is controlled by control parameters. The dual active bridge inverter adjusts the grid-connected current output from the grid-connected port according to the control parameters. The grid-connected port is the port where the dual active bridge inverter is connected to the grid.

[0071] In the above embodiment, the input voltage of the dual-active bridge inverter is obtained; based on the fluctuation of the input voltage, the current adjustment amount of the dual-active bridge inverter is determined; a current reference value is obtained, and control parameters are determined based on the updated current reference value and the current adjustment amount. The control parameters are used to control the operation of the dual-active bridge inverter and adjust the grid-connected current output from the grid-connected port of the dual-active bridge inverter. The embodiment of the present application adjusts the grid-connected current output by the dual-active bridge inverter based on the fluctuation of the input voltage of the dual-active bridge inverter, which not only achieves the effect of voltage stabilization but also reduces the distortion of the grid-connected current.

[0072] In an exemplary embodiment, Figure 3 As shown, the present application updates the current reference value once every half grid cycle, and the updating process may include the following steps:

[0073] Step 201 : calculating the effective value of the current according to the pre-established first correspondence between the instantaneous value and the effective value and the instantaneous value of the current every half power grid cycle.

[0074] A first correspondence between instantaneous value and effective value is pre-established, and the instantaneous value of current is calculated every half power grid cycle, and the instantaneous value of current is substituted into the first correspondence to calculate and obtain the effective value of current.

[0075] Step 202 : Calculate a current reference value based on a pre-established second correspondence between the effective value and the reference value and the current effective value, and determine the calculated current reference value as the current reference value for the current half grid cycle.

[0076] A second corresponding relationship between the effective value and the reference value is established in advance, the calculated current effective value is substituted into the second corresponding relationship for calculation to obtain the current reference value, and the calculated current reference value is determined as the current reference value of the current half grid cycle.

[0077] In some embodiments, the second correspondence includes a valid value and The product of is the reference value, that is, Igmbase = *I grms , where I gmbase is the current reference value, I grms is the effective value of current.

[0078] The complete update process may include: when the grid is riding, according to the current peak value I gmref The instantaneous current value I is calculated by the sine value of the phase-locked angle sinθ of the grid voltage gref , the instantaneous current value I gref Substituting into the above first corresponding relationship for calculation, we can get the effective value of current I grms ; Then the effective value of the current I grms Substituting into the above second corresponding relationship for calculation, the new current reference value I can be obtained. gmbase（n+1） ; Where n is the serial number of half a grid cycle.

[0079] In the above embodiment, every half grid cycle, the current effective value is calculated based on a pre-established first correspondence between the instantaneous value and the effective value and the instantaneous current value; the current reference value is calculated based on a pre-established second correspondence between the effective value and the reference value and the current effective value, and the current reference value is determined as the current reference value for the current half grid cycle. In the embodiment of the present application, by updating the current reference value once every half grid cycle, the accuracy of the instantaneous current value can be improved, thereby more accurately adjusting the grid-connected current and reducing grid-connected current distortion.

[0080] In an exemplary embodiment, Figure 4 As shown, in the above embodiment, “determining the control parameter according to the updated current reference value and the current adjustment amount” may include the following steps:

[0081] Step 301 : Calculate the current peak value of the current control cycle according to the updated current reference value and the current adjustment value, and calculate the current instantaneous value according to the current peak value.

[0082] Obtain the current reference value determined during the first half of the grid cycle. Calculate the peak current value for the current control cycle based on the current adjustment and the current reference value. Then, multiply the peak current value for the current control cycle by the sine value of the grid voltage phase-lock angle, sinθ. The product is the instantaneous current value.

[0083] For example, the current reference value determined in the first half of the grid cycle is I gmbase（n） , the current adjustment amount is ΔI gmref , according to I gmbase（n） and ΔI gmref Calculate the current peak value I of the current control cycle gmref , where n is the number of half a power grid cycle. The instantaneous current value Igref (t)=I gmref *sinθ(t), θ(t) is the grid phase angle at time t.

[0084] Step 302: Determine a control parameter according to the instantaneous value of the current.

[0085] The control parameter includes at least one of an inner phase shift angle and an outer phase shift angle.

[0086] The instantaneous value of the current is input into the grid-connected current loop, which can calculate the inner phase shift angle and the outer phase shift angle.

[0087] In the above embodiment, the current peak value of the current in the current control cycle is calculated based on the updated current reference value and current adjustment amount, and the instantaneous current value is calculated based on the current peak value; and the control parameters are determined based on the instantaneous current value. In the embodiment of the present application, the current peak value of the current in the current control cycle is recalculated based on the current adjustment amount and the current reference value, and a more accurate instantaneous current value can be calculated, thereby determining control parameters more suitable for the dual-active bridge inverter, thereby enabling the dual-active bridge inverter to adjust the grid-connected current in a timely manner and reduce grid-connected current distortion.

[0088] In an exemplary embodiment, Figure 5 As shown, in the above embodiment, “determining the current adjustment amount of the dual active bridge inverter according to the fluctuation of the input voltage” may include the following steps:

[0089] Step 401 : When the fluctuation of the input voltage meets the adjustment triggering condition, the voltage excess is calculated according to the input voltage and a preset voltage range.

[0090] After obtaining the input voltage of the dual-active bridge inverter, the system determines whether the input voltage fluctuation meets the adjustment trigger conditions. If the adjustment trigger conditions are not met, the grid-connected current does not need to be adjusted. If the adjustment trigger conditions are met, the grid-connected current does need to be adjusted. In this case, the voltage excess is calculated based on the input voltage and the preset voltage range.

[0091] For example, if the input voltage exceeds the upper limit of the preset voltage range, the difference between the input voltage and the upper limit of the preset voltage range is calculated to obtain the voltage excess. If the input voltage exceeds the lower limit of the preset voltage range, the difference between the lower limit of the preset voltage range and the input voltage is calculated to obtain the voltage excess.

[0092] Step 402 : converting the voltage excess according to a pre-established voltage-current conversion relationship to obtain a current adjustment value of the dual active bridge inverter.

[0093] Establish voltage-current conversion relationship in advance, such as ΔU=K*ΔI gmrefAfter determining the voltage excess ΔU, the voltage excess ΔU is substituted into the voltage-current conversion relationship to calculate the current adjustment ΔI of the dual active bridge inverter. gmref .

[0094] In the above embodiment, when the input voltage fluctuation meets the adjustment trigger condition, the voltage excess is calculated based on the input voltage and the preset voltage range; the voltage excess is converted according to the pre-established voltage-to-current conversion relationship to obtain the current adjustment value of the dual-active bridge inverter. The embodiment of the present application determines whether the grid-connected current needs to be adjusted based on the input voltage fluctuation, and can promptly calculate the current adjustment value, thereby adjusting the grid-connected current in a timely manner.

[0095] In an exemplary embodiment, the process of determining whether the adjustment trigger condition is met may include: when the input voltage exceeds a preset voltage range, determining that the fluctuation of the input voltage meets the adjustment trigger condition.

[0096] After obtaining the input voltage of the dual active bridge inverter, the input voltage is compared with the preset voltage range. If the input voltage does not exceed the preset voltage range, it is determined that the fluctuation of the input voltage does not meet the adjustment trigger condition and the grid-connected current does not need to be adjusted.

[0097] If the input voltage exceeds the preset voltage range, the input voltage fluctuation is determined to meet the adjustment trigger condition, and the grid-connected current needs to be adjusted. In this case, the voltage excess is calculated, and the current adjustment amount of the dual-active bridge inverter is calculated based on the voltage excess. Then, the control parameters are determined based on the current adjustment amount. The control parameters are used to control the dual-active bridge inverter, thereby adjusting the grid-connected current output by the dual-active bridge inverter.

[0098] In the above embodiment, when the input voltage exceeds the preset voltage range, it is determined that the fluctuation of the input voltage meets the adjustment trigger condition. The embodiment of the present application determines whether the fluctuation of the input voltage meets the adjustment trigger condition based on the preset voltage range, providing a basis for determining whether to adjust the grid-connected current.

[0099] In an exemplary embodiment, Figure 6 As shown, the process of determining whether the adjustment trigger condition is met may further include the following steps:

[0100] Step 501: Calculate a voltage error according to an input voltage and a reference voltage.

[0101] The voltage error is the difference between the reference voltage and the input voltage. For example, the input voltage is Vbus sample , the reference voltage is Vbus ref , voltage error Err = Vbus ref -Vbus sample.

[0102] Step 502 : Calculate an error range based on a preset voltage range and a reference voltage.

[0103] The upper limit of the error range is the difference between the upper limit of the preset voltage range and the reference voltage; the lower limit of the error range is the difference between the reference voltage and the lower limit of the preset voltage range. For example, the upper limit of the preset voltage range is VupperLimit, the lower limit of the preset voltage range is VunderLimit, and the upper limit of the error range Err_upperLimit = VupperLimit - Vbus ref , the lower limit of the error range Err_underLimit = Vbus ref -VunderLimit.

[0104] Step 503: When the voltage error exceeds the error range, determine whether the fluctuation of the input voltage meets the adjustment trigger condition.

[0105] If the voltage error does not exceed the upper limit of the error range, nor does it exceed the lower limit of the error range, it is determined that the fluctuation of the input voltage does not meet the adjustment trigger condition, and the grid-connected current does not need to be adjusted.

[0106] If the voltage error exceeds the upper limit of the error range, or if the voltage error exceeds the lower limit of the error range, the input voltage fluctuation is determined to meet the adjustment trigger condition, and the grid-connected current needs to be adjusted. In this case, if the voltage error exceeds the upper limit of the error range, the difference between the voltage error and the upper limit of the error range is calculated to obtain the voltage excess; if the voltage error exceeds the lower limit of the error range, the difference between the lower limit of the error range and the voltage error is calculated to obtain the voltage excess. After calculating the voltage excess, the current adjustment of the dual-active bridge inverter is calculated based on the voltage-current conversion relationship and the voltage excess. Then, control parameters are determined based on the current adjustment, and the dual-active bridge inverter is controlled using the control parameters to adjust the grid-connected current output from the grid-connected port of the dual-active bridge inverter.

[0107] In the above embodiment, the voltage error is calculated based on the input voltage and the reference voltage; the error range is calculated based on the preset voltage range and the reference voltage; and if the voltage error exceeds the error range, the input voltage fluctuation is determined to meet the adjustment trigger condition. This embodiment of the present application determines whether the adjustment trigger condition is met based on the input voltage, the reference voltage, and the preset voltage range, providing a basis for determining whether to adjust the grid-connected current.

[0108] In an exemplary embodiment, Figure 7 As shown, the process of determining the preset voltage range may include the following steps:

[0109] Step 601: When the dual active bridge inverter is in a preset working state, obtain a voltage fluctuation range of a low-voltage bus capacitor.

[0110] The preset working state includes that the input device of the dual active bridge inverter is a constant voltage DC source, and the power of the constant voltage DC source is greater than the peak output power of the dual active bridge inverter.

[0111] When determining the preset voltage range, a constant voltage DC source is used as an input device for the dual-active bridge inverter, and the power of the constant voltage DC source is set to be greater than the peak output power of the dual-active bridge inverter. The dual-active bridge inverter operates in this state, and then the voltage fluctuation range of the low-voltage bus capacitor when the dual-active bridge inverter is operating is obtained.

[0112] Step 602: Determine a preset voltage range based on the voltage fluctuation range of the low-voltage bus capacitor.

[0113] The upper limit of the voltage fluctuation range of the low-voltage bus capacitor is determined as the upper limit of the preset voltage range; the lower limit of the voltage fluctuation range of the low-voltage bus capacitor is determined as the lower limit of the preset voltage range. Alternatively, the upper limit of the voltage fluctuation range of the low-voltage bus capacitor is adjusted to obtain the upper limit of the preset voltage range; the lower limit of the voltage fluctuation range of the low-voltage bus capacitor is adjusted to obtain the lower limit of the preset voltage range.

[0114] In the above embodiment, when the dual-active bridge inverter is in a preset operating state, the voltage fluctuation range of the low-voltage bus capacitor is obtained; and the preset voltage range is determined based on the voltage fluctuation range of the low-voltage bus capacitor. In the embodiment of the present application, a constant-voltage DC source is used to stabilize the input voltage of the dual-active bridge inverter, thereby determining a relatively accurate preset voltage range, so that the need for grid-connected current adjustment can be accurately determined based on the preset voltage range.

[0115] In an exemplary embodiment, a control method for a dual active bridge inverter is provided, wherein the method is applied to Figure 1a The grid-side converter in the wind power generation system is used as an example to illustrate the process, which includes the following steps:

[0116] Step 1: When the dual active bridge inverter is in a preset working state, obtain the voltage fluctuation range of the low-voltage bus capacitor.

[0117] The preset working state includes that the input device of the dual active bridge inverter is a constant voltage DC source, and the power of the constant voltage DC source is greater than the peak output power of the dual active bridge inverter.

[0118] Step 2: Determine a preset voltage range based on the voltage fluctuation range of the low-voltage bus capacitor.

[0119] Step 3: Obtain the input voltage of the dual active bridge inverter.

[0120] Step 4, when the input voltage exceeds the preset voltage range, determine that the fluctuation of the input voltage meets the adjustment trigger condition, and / or, calculate the voltage error based on the input voltage and the reference voltage; calculate the error range based on the preset voltage range and the reference voltage; when the voltage error exceeds the error range, determine that the fluctuation of the input voltage meets the adjustment trigger condition.

[0121] Step 5: When the fluctuation of the input voltage meets the adjustment trigger condition, the voltage excess is calculated according to the input voltage and the preset voltage range.

[0122] Step 6: convert the voltage excess according to the pre-established voltage-current conversion relationship to obtain the current adjustment value of the dual active bridge inverter.

[0123] Step 7: Obtain a current reference value based on the instantaneous current value.

[0124] Step 8: Calculate the current peak value of the current control cycle according to the updated current reference value and the current adjustment amount, and calculate the current instantaneous value according to the current peak value.

[0125] Among them, every half grid cycle, the current effective value is calculated based on a pre-established first correspondence between the instantaneous value and the effective value and the instantaneous value of the current; the current reference value is calculated based on a pre-established second correspondence between the effective value and the reference value and the effective value of the current, and the calculated current reference value is determined as the current reference value of the current half grid cycle.

[0126] Step 9: Determine a control parameter according to the instantaneous value of the current; wherein the control parameter includes at least one of an inner phase shift angle and an outer phase shift angle.

[0127] Step 10: Use the control parameters to control the operation of the dual active bridge inverter and adjust the grid-connected current output from the grid-connected port of the dual active bridge inverter.

[0128] The above process can refer to Figure 8As shown, during grid ride-through, the instantaneous current value is calculated based on the peak current value, the effective current value is calculated based on the instantaneous current value, and the current reference value is updated based on the effective current value. During the current control cycle (50μs), if the input voltage fluctuation meets the adjustment trigger condition, the current adjustment amount is calculated based on the input voltage fluctuation. The current peak value for the current control cycle is calculated based on the updated current reference value and the current adjustment amount. The instantaneous current value is then calculated based on the peak current value. The control parameters are then determined based on the instantaneous current value. These control parameters are used to control the operation of the dual-active bridge inverter and adjust the grid-connected current output by the dual-active bridge inverter. Within a 1ms cycle, the startup conditions are checked and upper limits for the output power and grid-connected current are set.

[0129] In the above embodiment, the grid-connected current output by the dual active bridge inverter is adjusted according to the fluctuation of the input voltage of the dual active bridge inverter, which not only achieves the effect of voltage stabilization but also reduces the distortion of the grid-connected current.

[0130] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0131] Based on the same inventive concept, embodiments of the present application also provide a dual-active bridge inverter control device for implementing the aforementioned dual-active bridge inverter control method. The solution provided by this device is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more of the following dual-active bridge inverter control device embodiments can be found in the aforementioned limitations of the dual-active bridge inverter control method and will not be further elaborated here.

[0132] In an exemplary embodiment, Figure 9 As shown, a control device for a dual active bridge inverter is provided, comprising:

[0133] An input voltage acquisition module 701 is used to acquire the input voltage of the dual active bridge inverter;

[0134] An adjustment amount determination module 702 is configured to determine a current adjustment amount of the dual active bridge inverter according to fluctuations in the input voltage;

[0135] The control module 703 is used to obtain a current reference value, determine a control parameter according to the updated current reference value and the current adjustment amount, and use the control parameter to control the operation of the dual active bridge inverter to adjust the grid-connected current output by the dual active bridge inverter from the grid-connected port.

[0136] In one embodiment, the apparatus further comprises:

[0137] an effective value determination module, configured to calculate the effective value of the current according to a pre-established first correspondence between the instantaneous value and the effective value and the instantaneous value of the current every half power grid cycle;

[0138] The reference value updating module is used to calculate the current reference value according to the pre-established second corresponding relationship between the effective value and the reference value and the current effective value, and determine the calculated current reference value as the current peak value of the current half grid cycle.

[0139] In one embodiment, the control module 703 is specifically used to calculate the current peak value of the current control cycle based on the updated current reference value and the current adjustment amount, and calculate the instantaneous current value based on the current peak value; determine the control parameters based on the instantaneous current value; wherein the control parameters include at least one of the inner phase shift angle and the outer phase shift angle.

[0140] In one embodiment, the adjustment amount determination module 702 is specifically configured to calculate a voltage excess amount based on the input voltage and a preset voltage range when the fluctuation of the input voltage meets the adjustment trigger condition; and convert the voltage excess amount according to a pre-established voltage-to-current conversion relationship to obtain a current adjustment amount of the dual active bridge inverter.

[0141] In one embodiment, the apparatus further comprises:

[0142] The first judgment module is configured to determine whether the fluctuation of the input voltage meets the adjustment triggering condition when the input voltage exceeds a preset voltage range.

[0143] In one embodiment, the apparatus further comprises:

[0144] An error amount determination module is used to calculate a voltage error amount according to an input voltage and a reference voltage;

[0145] An error range determination module is used to calculate the error range based on a preset voltage range and a reference voltage;

[0146] The second judgment module is used to determine whether the fluctuation of the input voltage meets the adjustment trigger condition when the voltage error exceeds the error range.

[0147] In one embodiment, the apparatus further comprises:

[0148] a fluctuation range determination module, configured to obtain a voltage fluctuation range of the low-voltage bus capacitor when the dual-active bridge inverter is in a preset operating state; wherein the preset operating state includes an input device of the dual-active bridge inverter being a constant-voltage DC source, and the power of the constant-voltage DC source being greater than the peak output power of the dual-active bridge inverter;

[0149] The voltage range determination module is used to determine a preset voltage range according to the voltage fluctuation range of the low-voltage bus capacitor.

[0150] Each module in the control device for the dual-active bridge inverter described above can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in an electronic device in hardware form, or can be stored in a memory in the electronic device in software form, so that the processor can call and execute the corresponding operations of each module.

[0151] In an exemplary embodiment, an electronic device is provided. The electronic device can be set in an inverter, and its internal structure can be as shown in FIG. Figure 10 As shown. The electronic device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the electronic device is used to store control data of the dual active bridge inverter. The input / output interface of the electronic device is used to exchange information between the processor and an external device. The communication interface of the electronic device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a control method for a dual active bridge inverter is implemented.

[0152] Those skilled in the art will understand that Figure 10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the electronic device to which the solution of the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0153] In an exemplary embodiment, a non-transitory computer-readable storage medium including instructions, such as a memory including instructions, is also provided. The instructions are executable by a processor of an electronic device to perform the above method. For example, the non-transitory computer-readable storage medium may be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, or the like.

[0154] In an exemplary embodiment, a computer program product is also provided. When executed by a processor, the computer program can implement the above method. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, part or all of the above method can be implemented in whole or in part according to the processes or functions described in the embodiments of this application.

[0155] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the 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 above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), data processing logic devices based on quantum computing, and the like.

[0156] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0157] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A control method for a dual active bridge inverter, characterized in that: Applied to a wind power system, the method includes: Obtaining an input voltage of the dual active bridge inverter; determining a current adjustment amount of the dual active bridge inverter according to the fluctuation of the input voltage and a pre-established correspondence between the fluctuation amount of the input voltage and the current adjustment amount; After every half power grid cycle, the effective value of the current is calculated according to the pre-established first corresponding relationship between the instantaneous value and the effective value and the instantaneous value of the current; Calculating a current reference value based on a pre-established second correspondence between an effective value and a reference value and the current effective value, and determining the calculated current reference value as the current reference value for the current half grid cycle; Obtaining a current reference value, determining a control parameter based on the current reference value updated every half grid cycle and the current adjustment amount, and using the control parameter to control the operation of the dual active bridge inverter to adjust the grid-connected current output by the dual active bridge inverter from the grid-connected port; The step of determining the control parameter based on the current reference value updated every half grid cycle and the current adjustment amount includes: Calculating the current peak value of the current control cycle according to the current reference value updated in each half grid cycle and the current adjustment amount, and calculating the current instantaneous value according to the current peak value; A control parameter is determined according to the instantaneous value of the current; wherein the control parameter includes at least one of an inner phase shift angle and an outer phase shift angle.

2. The method according to claim 1, characterized in that The determining the current adjustment amount of the dual active bridge inverter according to the fluctuation of the input voltage and a pre-established correspondence between the fluctuation amount of the input voltage and the current adjustment amount includes: When the fluctuation of the input voltage meets the adjustment trigger condition, calculating the voltage excess amount according to the input voltage and a preset voltage range; The voltage excess is converted according to the corresponding relationship between the input voltage fluctuation amount and the current adjustment amount to obtain the current adjustment amount of the dual active bridge inverter.

3. The method according to claim 2, characterized in that The method further comprises: In a case where the input voltage exceeds the preset voltage range, it is determined that the fluctuation of the input voltage meets the adjustment triggering condition.

4. The method according to claim 2, characterized in that The method further comprises: Calculating a voltage error according to the input voltage and the reference voltage; Calculating an error range according to the preset voltage range and the reference voltage; When the voltage error exceeds the error range, it is determined that the fluctuation of the input voltage meets the adjustment trigger condition.

5. The method according to claim 2, characterized in that The method further comprises: When the dual-active bridge inverter is in a preset working state, obtaining a voltage fluctuation range of the low-voltage bus capacitor; wherein the preset working state includes that the input device of the dual-active bridge inverter is a constant-voltage DC source, and the power of the constant-voltage DC source is greater than the peak output power of the dual-active bridge inverter; The preset voltage range is determined according to the voltage fluctuation range of the low-voltage bus capacitor.

6. A control device for a dual active bridge inverter, characterized in that: Applied to a wind power system, the device comprises: An input voltage acquisition module, configured to acquire the input voltage of the dual active bridge inverter; an adjustment amount determining module, configured to determine a current adjustment amount of the dual active bridge inverter according to the fluctuation of the input voltage and a pre-established correspondence between the fluctuation amount of the input voltage and the current adjustment amount; an effective value determination module, configured to calculate the effective value of the current according to a pre-established first correspondence between the instantaneous value and the effective value and the instantaneous value of the current every half power grid cycle; a reference value updating module, configured to calculate a current reference value based on a pre-established second correspondence between the effective value and the reference value and the current effective value, and determine the calculated current reference value as the current reference value for the current half grid cycle; a control module, configured to obtain a current reference value, determine a control parameter based on the current reference value updated every half grid cycle and the current adjustment amount, and use the control parameter to control the operation of the dual active bridge inverter to adjust the grid-connected current output by the dual active bridge inverter from the grid-connected port; Among them, the control module is specifically used to calculate the current peak value of the current control cycle based on the current reference value updated in each half grid cycle and the current adjustment amount, and calculate the instantaneous current value based on the current peak value; determine the control parameters based on the instantaneous current value; wherein, the control parameters include at least one of the inner phase shift angle and the outer phase shift angle.

7. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

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

9. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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