Control method of dual active bridge converter, energy storage equipment and readable storage medium

Abstract

A control method of a dual active bridge converter, an energy storage device and a readable storage medium, the control method comprising: determining a feedforward value of an external phase shift angle and an adjustment value of the external phase shift angle according to an electrical parameter of the dual active bridge converter; and controlling the energy conversion of the dual-active bridge converter according to the feed-forward value of the external phase shift angle and the adjustment value of the external phase shift angle. When the dual active bridge converter performs energy conversion according to the generated driving signal, the feed-forward value of the external phase shift angle can be actively adjusted based on the target alternating current so as to adjust the given value of the external phase shift angle, so that the given value of the external phase shift angle can change along with the change of the target power supply current; therefore, the generated driving signal can actively adjust the output actual alternating current in time, and the purpose of reducing the output current or voltage waveform oscillation of the dual-active bridge converter is achieved.

Description

Technical Field

[0001] This application belongs to the field, and in particular relates to a control method for a dual active bridge converter, an energy storage device, and a readable storage medium. Background Art

[0002] At present, the dual active bridge (DAB) topology is a single-stage topology, which has advantages such as lower device cost and higher transmission efficiency compared to the traditional two-stage grid-connected and off-grid inverter topology (for example, a two-stage topology composed of an LLC resonant circuit and an inverter).

[0003] During the process of switching the energy flow direction in the dual active bridge topology, the positive and negative signs of the external phase shift angle are directly determined by the power reference sign. Therefore, the adjustment of the external phase shift angle needs to be carried out after obtaining the power reference sign. During the actual adjustment process, voltage or current waveform jitter will occur during bidirectional switching, which will affect the output power quality and may cause equipment damage and failures in severe cases. Summary of the Invention

[0004] The purpose of this application is to provide a control method for a dual active bridge converter, an energy storage device, and a readable storage medium, aiming to solve the problem of output current or voltage fluctuations that easily occur when the traditional dual active bridge topology changes the energy flow direction.

[0005] In the first aspect of the embodiments of this application, a control method for a dual active bridge converter is provided. The dual active bridge converter includes a DC-side bridge circuit, a transformer, and an AC-side bridge circuit. The first end of the DC-side bridge circuit is connected to the primary side of the transformer, the second end of the DC-side bridge circuit is used to connect at least one of a DC power supply and a DC load, the secondary side of the transformer is connected to the first end of the AC-side bridge circuit, and the second end of the AC-side bridge circuit is used to connect at least one of a power grid and an AC load. The control method includes: obtaining the actual AC current, target AC current, actual DC voltage, and minimum switching frequency of the dual active bridge converter; determining a feedforward value of the external phase shift angle of the dual active bridge converter according to the target AC current, the actual DC voltage, the minimum switching frequency, and the circuit parameters of the transformer; determining an adjustment value of the external phase shift angle according to the target AC current and the actual AC current; determining a given value of the external phase shift angle according to the feedforward value of the external phase shift angle and the adjustment value of the external phase shift angle; determining a target switching frequency and a target internal phase shift angle according to the minimum switching frequency, the given value of the external phase shift angle, and a preset phase shift ratio; generating a driving signal according to the given value of the external phase shift angle, the target switching frequency, and the target internal phase shift angle, and the driving signal is used to control the dual active bridge converter to perform energy conversion.

[0006] In one embodiment, the circuit parameters of the transformer include the turns ratio of the primary and secondary sides and the leakage inductance of the secondary side; determining the feed-forward value of the external phase shift angle of the dual-active-bridge converter according to the target alternating current, the actual direct current voltage, the minimum switching frequency, and the circuit parameters of the transformer includes: determining the feed-forward value of the external phase shift angle of the dual-active-bridge converter according to the actual direct current voltage, the leakage inductance of the secondary side, the turns ratio of the primary and secondary sides, the minimum switching frequency, and the target alternating current.

[0007] In one embodiment, the feed-forward value of the external phase shift angle has a positive correlation with the minimum switching frequency; the feed-forward value of the external phase shift angle has a positive correlation with the target alternating current; the feed-forward value of the external phase shift angle has a positive correlation with the proportionality coefficient.

[0008] In one embodiment, the feed-forward value of the external phase shift angle has a negative correlation with both the actual direct current voltage and the turns ratio of the primary and secondary sides, and has a positive correlation with the leakage inductance of the secondary side.

[0009] In one embodiment, determining the adjustment value of the external phase shift angle according to the target alternating current and the actual alternating current includes: obtaining a difference according to the target alternating current and the actual alternating current; performing a deviation operation on the difference to obtain the adjustment value of the external phase shift angle.

[0010] In one embodiment, determining the given value of the external phase shift angle according to the feed-forward value of the external phase shift angle and the adjustment value of the external phase shift angle includes: summing the feed-forward value of the external phase shift angle and the adjustment value of the external phase shift angle to obtain the given value of the external phase shift angle.

[0011] In one embodiment, determining the target switching frequency and the target internal phase shift angle according to the minimum switching frequency, the given value of the external phase shift angle, and a preset phase shift ratio includes: obtaining the target internal phase shift angle according to the product of the absolute value of the given value of the external phase shift angle and the preset phase shift ratio; determining the target switching frequency according to the minimum switching frequency, the preset phase shift ratio, and the given value of the external phase shift angle.

[0012] In one embodiment, the target switching frequency has a positive correlation with the minimum switching frequency; the target switching frequency has a negative correlation with the given value of the external phase shift angle.

[0013] A second aspect of the embodiments of the present application provides an energy storage device, including a dual-active-bridge converter, a memory, a processor, and a computer program stored in the memory and executable on the processor. The dual-active-bridge converter includes a DC-side bridge circuit, a transformer, and an AC-side bridge circuit. The first end of the DC-side bridge circuit is connected to the primary side of the transformer, and the second end of the DC-side bridge circuit is used to connect at least one of a DC power supply and a DC load. The secondary side of the transformer is connected to the first end of the AC-side bridge circuit, and the second end of the AC-side bridge circuit is used to connect at least one of a power grid and an AC load. The processor is connected to the dual-active-bridge converter, and when the processor executes the computer program, it implements the control method of the dual-active-bridge converter as described above.

[0014] A third aspect of the embodiments of the present application provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a controller, it implements the steps of the control method of the dual-active-bridge converter as described above.

[0015] The beneficial effects of the embodiments of the present application compared with the related art are as follows: Since the feedforward value of the external phase-shift angle is obtained based on the target AC current, the actual DC voltage, the minimum switching frequency, and the circuit parameters of the transformer, when the target AC current changes, the corresponding feedforward value of the external phase-shift angle can be actively adjusted in a timely manner. Then, based on the feedforward value of the external phase-shift angle and the adjustment value of the external phase-shift angle, the given value of the external phase-shift angle is determined to obtain the drive signal for the dual-active-bridge converter. Therefore, during the output control process, the feedforward value of the external phase-shift angle can be actively adjusted based on the target AC current, and then the given value of the external phase-shift angle is adjusted, so that the given value of the external phase-shift angle can change with the change of the target AC current, thereby enabling the generated drive signal to actively adjust the actual AC current of the output in a timely manner, and further achieving the purpose of reducing the oscillation of the output current or voltage waveform of the dual-active-bridge converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a dual-active-bridge converter provided by an embodiment of the present application;

[0017] Figure 2 It is a circuit schematic diagram of a dual-active-bridge converter provided by an embodiment of the present application;

[0018] Figure 3A It is a timing diagram when the dual-active-bridge converter performs inversion;

[0019] Figure 3B It is a timing diagram when the dual-active-bridge converter performs rectification;

[0020] Figure 4Flow chart of the control method provided by an embodiment of the present application;

[0021] Figure 5 For Figure 4 Specific flow chart of step S200 in

[0022] Figure 6 For Figure 5 Specific flow chart of step S210 in

[0023] Figure 7 For Figure 4 Specific flow chart of step S300 in

[0024] Figure 8 For Figure 4 Specific flow chart of step S500 in

[0025] Figure 9 Control block diagram provided by an embodiment of the present application;

[0026] Figure 10A Simulation waveform diagram when controlled by the traditional method;

[0027] Figure 10B Simulation waveform diagram when controlled by the control method of the embodiment of the present application;

[0028] Figure 11 Schematic diagram of the control device provided by an embodiment of the present application;

[0029] Figure 12 Schematic diagram of the energy storage device provided by an embodiment of the present application;

[0030] Figure 13 Schematic diagram of the computer-readable storage medium provided by an embodiment of the present application. Specific implementation manners

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application will be further described in detail below with reference to 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.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality of" means two or more, unless otherwise specifically defined.

[0034] In the traditional dual-active-bridge converter, since different control logics are required to separately implement the control of charging and discharging (i.e., the forward and reverse flows of energy), the overall control process is relatively complex.

[0035] Please refer to Figure 1 , which is an application scenario diagram of the control method for the dual-active-bridge converter according to the embodiment of this application. Figure 1 The scenario includes a dual-active-bridge converter 10, a DC power supply 20, a DC load 30, a power grid 40, an AC load 50, and a controller 60.

[0036] Specifically, the dual-active-bridge converter 10 includes a DC-side bridge circuit 100, a transformer 200, and an AC-side bridge circuit 300. The first end of the DC-side bridge circuit 100 is connected to the primary side of the transformer 200, and the second end of the DC-side bridge circuit 100 is used to connect to the DC power supply 20 and the DC load 30. The secondary side of the transformer 200 is connected to the first end of the AC-side bridge circuit 300, and the second end of the AC-side bridge circuit 300 is used to connect to the power grid 40 and the AC load 50.

[0037] The DC-side bridge circuit 100 can be used to invert the energy of the DC power supply 20 and transmit it to the transformer 200. The transformer 200 then transmits the energy to the AC-side bridge circuit 300 through the magnetic field. The AC-side bridge circuit 300 can be used to convert the energy and transmit it to the AC load 50 or feed it into the power grid 40. Conversely, the AC-side bridge circuit 300 can be used to convert the energy of the power grid 40 and transmit it to the transformer 200. The transformer 200 then transmits the energy to the DC-side bridge circuit 100 through the magnetic field. The DC-side bridge circuit 100 can be used to rectify the energy and transmit it to the DC load 30. Thus, it can be seen that the dual-active-bridge converter 10 can achieve bidirectional energy flow.

[0038] Among them, the direction in which energy flows from the DC-side bridge circuit 100 to the AC-side bridge circuit 300 can be defined as the forward direction, and the direction in which energy flows from the AC-side bridge circuit 300 to the DC-side bridge circuit 100 is the reverse direction. That is, taking current as an example, when the current flows from the DC-side bridge circuit 100 to the AC-side bridge circuit 300, the sign of the current is positive; when the current flows from the AC-side bridge circuit 300 to the DC-side bridge circuit 100, the sign of the current is negative. It can be understood that among the circuit parameters of the transformer 200, the turns ratio of the primary and secondary windings can be 1:N, where N is a positive number greater than 1. Therefore, the primary side of the transformer 200 can be regarded as the low-voltage side, and the secondary side of the transformer 200 can be regarded as the high-voltage side. The forward flow of energy can be regarded as discharging, and the reverse flow of energy can be regarded as charging. In other embodiments, the turns ratio of the primary and secondary windings is also N:1, which is specifically determined according to whether the transformer is used for step-up or step-down. Of course, in other embodiments, the forward and reverse directions can be reversed, which can be determined according to the actual situation, and all are within the scope of the embodiments of the present application.

[0039] In some embodiments, the DC-side bridge circuit 100 can also be connected only to the DC power supply 20 or the DC load 30. In other embodiments, the AC-side bridge circuit 300 can also be connected only to the AC load 50 or the power grid 40. It can be understood that if the AC-side bridge circuit 300 is connected to the power grid 40, the operating condition of the dual-active-bridge converter 10 at this time can be called the grid-connected condition. If the AC-side bridge circuit 300 is not connected to the power grid 40, the operating condition of the dual-active-bridge converter 10 at this time can be called the off-grid condition.

[0040] In the embodiments of the present application, the DC-side bridge circuit 100 and the AC-side bridge circuit 300 are also respectively connected to the controller 60. The controller 60 can be used to control the DC-side bridge circuit 100 to implement the DC-AC (that is, Direct Current - Alternating Current) conversion function, and control the AC-side bridge circuit 300 to implement the AC-AC (that is, Alternating Current - Alternating Current) conversion function.

[0041] Among them, the DC-side bridge circuit 100 can adopt a full-bridge topology or a half-bridge topology, and the AC-side bridge circuit 300 can also adopt a full-bridge topology or a half-bridge topology, which is not limited here. The controller 60 can adopt a microcontroller unit (MCU) or other control circuits.

[0042] The DC power supply 20 can be a storage battery, a photovoltaic power generation device, or other power supplies that can provide direct current. The DC load 30 can be any electronic load that consumes direct current. It can be understood that since the storage battery can receive energy for charging, the storage battery can also be used as a DC load.

[0043] The power grid 40 can be a municipal power grid, other local power grids, or a microgrid. The AC load 50 can be any electronic load that consumes alternating current. For example, the AC load 50 can be a motor or various AC loads in a household, and for another example, the AC load 50 can be a resistive load, an inductive load, a capacitive load, an RCD load (including a capacitor, a resistor, and a diode), or other non-linear loads, etc.

[0044] Furthermore, if the energy of the dual-active-bridge converter 10 flows forward, the operating condition at this time can be called the inversion condition, that is, the dual-active-bridge converter 10 converts the direct current of the DC power supply 20 into alternating current and then outputs it to the AC load 50 or the power grid 40. If the energy of the dual-active-bridge converter 10 flows backward, the operating condition at this time can be called the rectification condition, that is, the dual-active-bridge converter 10 rectifies the alternating current provided by the power grid 40 or other AC power supplies into direct current and then supplies power to the DC load 30 or charges the DC power supply 20.

[0045] For better understanding, the following takes Figure 2 the circuit shown as an example to further illustrate the dual-active-bridge converter 10. In Figure 2 the dual-active-bridge converter 10 shown, the DC-side bridge circuit 100 adopts a full-bridge topology. The AC-side bridge circuit 300 adopts a half-bridge topology.

[0046] Specifically, as Figure 2 shown, the DC-side bridge circuit 100 includes switching tubes S1 to S4. The switching tubes S1 and S2 are connected in series to form one arm, and the switching tubes S3 and S4 are connected in series to form another arm. The two arms are connected in parallel. The midpoints of the two arms (corresponding to Figure 2 points a and b in) form the first end of the DC-side bridge circuit 100. The two ends of the two arms form the second end of the DC-side bridge circuit 100.

[0047] A first capacitor unit can also be connected in parallel between the DC-side bridge circuit 100 and the DC power supply 20. Among them, the first capacitor unit can include a series-connected capacitor C1 and resistor R1. Of course, in other embodiments, the first capacitor unit can also directly adopt the capacitor C1, or other circuits including the capacitor C1.

[0048] The AC-side bridge circuit 300 includes switching transistors S5 to S8, a second capacitor unit, and a third capacitor unit. The switching transistors S5 to S8 form a first bridge arm, and the second capacitor unit and the third capacitor unit form a second bridge arm. Specifically, the switching transistors S5 and S6 are connected in series and oppositely arranged (i.e., connected in reverse series) to form the upper bridge arm of the first bridge arm, and the switching transistors S7 and S8 are connected in series and oppositely arranged to form the lower bridge arm of the first bridge arm. The upper bridge arm and the lower bridge arm are connected in series to form the first bridge arm. The second capacitor unit forms the upper bridge arm of the second bridge arm, and the third capacitor unit forms the lower bridge arm of the second bridge arm. The second capacitor unit and the third capacitor unit are connected in series to form the second bridge arm. The midpoints of the two bridge arms (corresponding to Figure 2 points c and d therein) form the first end of the AC-side bridge circuit 300. The two ends of the two bridge arms form the second end of the AC-side bridge circuit 300. Among them, the structures of the second capacitor unit and the third capacitor unit can be the same as or similar to that of the first capacitor unit. For example, Figure 2 the second capacitor unit in

[0049] includes a series-connected capacitor C2 and resistor R2, and the third capacitor unit includes a series-connected capacitor C3 and resistor R3. Figure 2 It can be understood that the switching transistors S1 to S4, S5 to S8 can adopt corresponding types of semiconductor switches according to actual situations, such as triodes, MOSFETs, or IGBTs, etc. The present application does not make specific limitations on this. The switching transistors S1 to S4, S5 to S8 can all be used to receive control signals from the controller 60, and then conduct or turn off under the control of the control signals. Among them, the control signal can be a Pulse Width Modulation (PWM) signal, such as

[0050] the control signals of the switching transistors S1 to S8 in k are correspondingly shown as PWM1 to PWM8. The duty cycle and switching frequency of the PWM signal determine the on-off conditions of the switching transistors S1 to S8 (including on-off states, on-off times, on-off durations, etc.), and thus affect the energy transfer of the dual-active-bridge converter 10. k The dual-active-bridge converter 10 may further include a secondary leakage inductance L Figure 2 . The secondary leakage inductance L Figure 2 can be independently set or integrated into the transformer 200 (see k Tr in k ) as a circuit parameter of the transformer 200. For ease of understanding,

[0051] the secondary leakage inductance L Figure 3A and Figure 3B are shown in the circuit of Figure 3A . The secondary leakage inductance L k is connected between the secondary side of the transformer 200 and the midpoint c of the bridge arm.

[0051] Please also refer to Figure 3A and Figure 3B Figure 3A shows the timing diagram when the dual-active-bridge converter 10 realizes forward energy flow.Figure 3B shows the timing diagram when the dual-active-bridge converter 10 realizes the energy reverse flow. Among them, in a complete switching period t s , the operating conditions of the DC-side bridge circuit 100 in the positive and negative half-cycles are symmetric, and the same is true for the AC-side bridge circuit 300. Therefore, Figure 3A and Figure 3B show the timing diagram of the positive half-cycle (t0~t s / 2). The timing diagram of the negative half-cycle (t s / 2~t s ) can refer to the timing diagram of the positive half-cycle and will not be described here.

[0052] Specifically, as Figure 3A shown, the switching tubes of the same bridge arm in the DC-side bridge circuit 100 (i.e., S1 and S2, S3 and S4) conduct alternately at a high frequency, and two switching tubes in different bridge arms and in the diagonal direction in the DC-side bridge circuit 100 (i.e., S1 and S4, S2 and S3) conduct or turn off successively with a certain phase angle difference. Correspondingly, there is also a corresponding phase angle difference between the control signals. This phase angle difference is also called the internal phase-shift angle φ of the DC-side bridge circuit 100, or can also be called the primary-side internal phase-shift angle φ. For example, in this embodiment, the phase angle difference between the control signals of the switching tubes S1 and S4 or the phase angle difference between the control signals of the switching tubes S2 and S3 is called the primary-side internal phase-shift angle φ.

[0053] In the positive or negative half-cycle, for a part of the time, two switching tubes in different bridge arms and in the diagonal direction conduct simultaneously (such as S1 and S4), and for another part of the time, two switching tubes in the same position of different bridge arms conduct simultaneously (such as S1 and S3). It should be understood that the specific on-off logic can be controlled according to the actual required output voltage, etc., and is not limited to the drawings and the implementation methods mentioned above.

[0054] Therefore, when the first end of the DC-side bridge circuit 100 is connected to the actual DC voltage V dc provided by the DC power supply 20, the DC-side bridge circuit 100 can convert V dc so that the midpoint voltage V p between points a and b of the DC-side bridge circuit 100 is generated. The phase-shift angle of V p (or can also be called the phase angle of V p ) is equal to the primary-side internal phase-shift angle φ.

[0055] Please continue to refer to Figure 3A, in this embodiment, the upper and lower arms of the first arm of the AC-side bridge circuit 300 will alternately be in the on or off state. Specifically, the states of the two switching transistors (such as S5 and S6) of the upper arm alternate, and the states of the two switching transistors (such as S7 and S8) of the lower arm alternate, so as to realize the conversion of the electric energy output by the transformer 200 and supply power to the load. Taking Figure 2 the embodiment of

[0056] As both the upper arm and the lower arm of the second arm are composed of resistors and capacitors, there will be no phase shift angle between adjacent arms. However, there will be a phase angle difference between the control signals of the switching transistors in the DC-side bridge circuit 100 and the control signals of the switching transistors in the AC-side bridge circuit 300. This phase angle difference is also called the external phase shift angle between the DC-side bridge circuit 100 and the AC-side bridge circuit 300. Referring to Figure 3A , the phase angle difference between the control signal of the switching transistor S1 and the control signals of the switching transistors S5 / S8 is called the external phase shift angle

[0057] Figure 4 FIG. shows a flowchart of a control method for a dual-active-bridge converter provided by an embodiment of the present application. For the sake of convenience of description, only the part related to this embodiment is shown and is described in detail as follows:

[0058] The control method can be applied to the dual-active-bridge converter 10 in any of the above embodiments to control each switching device in the DC-side bridge circuit 100 and the AC-side bridge circuit 300 in the dual-active-bridge converter 10. The control method includes step S100 to step S600.

[0059] Step S100: Obtain the actual AC current i g of the dual-active-bridge converter, the target AC current i g_ref , the actual DC voltage V dc and the minimum switching frequency f min .

[0060] The actual AC current i g is the current actually output at the second end of the AC-side bridge circuit 300. The target AC current i g_ref is the current expected to be output at the second end of the dual-active-bridge converter 10. The actual DC voltage V dc is the voltage actually input at the second end of the DC-side bridge circuit 100. The minimum switching frequency f min is the minimum allowed switching frequency of each switching device in the dual-active-bridge converter 10.

[0061] It can be understood that the actual alternating current i g and the actual direct current voltage V dc can be obtained by sampling the electrical signals in the dual-active-bridge converter 10 in each control period. The target alternating current i g_ref and the minimum switching frequency f min can be directly obtained or calculated according to the parameter settings of the dual-active-bridge converter 10. Among them, the target alternating current i g_ref and the minimum switching frequency f min can be set according to actual requirements, and the specific values thereof are not limited in this embodiment. The control period can be the period during which the controller 60 connected to the dual-active-bridge converter 10 executes steps S100 to S600, and the length of the control period can be determined according to actual situations, which is not limited in this embodiment.

[0062] Specifically, a current sampling circuit can be connected to the second end of the AC-side bridge circuit 300 to collect the actual alternating current i g , and a voltage sampling circuit can be connected to the second end of the DC-side bridge circuit 100 to collect the actual direct current voltage V dc . The current sampling circuit and the voltage sampling circuit can be part of the dual-active-bridge converter 10 or integrated in the controller 60. After collecting the above parameters, the controller 60 can record the actual alternating current i g and the actual direct current voltage V dc in the corresponding memory.

[0063] Step S200: Determine the feedforward value of the external phase-shift angle of the dual-active-bridge converter 10 according to the target alternating current i g_ref , the actual direct current voltage V dc , the minimum switching frequency f min and the circuit parameters of the transformer

[0064] Since the target alternating current is associated with the switching frequency, the circuit parameters of the transformer 200, and the external phase-shift angle , the feedforward value of the external phase-shift angle can be determined according to the association relationship between the target alternating current, the switching frequency, the circuit parameters of the transformer 200, and the external phase-shift angle That is, when the target alternating current i is determined, the feedforward value of the external phase-shift angle g_ref can be determined according to the target alternating current i . When the flowing direction of the target alternating current i g_ref , that is, the sign, is determined, the feedforward value of the external phase-shift angle g_ref will also have a corresponding sign, so that it can follow the target alternating current i ​g_ref changes accordingly, has good timeliness, and then uses the feedforward value of the external phase shift angle to actively adjust the target external phase shift angle in a timely manner, realizing continuous adjustment of the target external phase shift angle to avoid large fluctuations in the output signal.

[0065] Step S300: Determine the adjustment value of the external phase shift angle according to the target alternating current i g_ref and the actual alternating current i g The adjustment value of the external phase shift angle

[0066] The adjustment value of the external phase shift angle can be obtained by closed-loop control and is used for feedback adjustment of the external phase shift angle of the dual-active-bridge converter 10. Then, based on the adjusted external phase shift angle control the dual-active-bridge converter 10 so that the output of the dual-active-bridge converter 10 meets the requirements.

[0067] Step S400: Determine the given value of the external phase shift angle according to the feedforward value of the external phase shift angle and the adjustment value of the external phase shift angle The given value of the external phase shift angle

[0068] The given value of the external phase shift angle obtained through the feedforward value of the external phase shift angle and the adjustment value of the external phase shift angle The given value of the external phase shift angle obtained So that the obtained given value of the external phase shift angle also has good continuous adjustability and can be dynamically adjusted according to the actual situation based on the adjustment value of the external phase shift angle to ensure that the actual output of the dual-active-bridge converter 10 can be as close as possible to the target output, thereby improving the accuracy and stability of system control. By increasing the feedforward value of the external phase shift angle the dynamic response speed of the system can be accelerated.

[0069] Step S500: Determine the target switching frequency f min and the target internal phase shift angle φ according to the given value of the external phase shift angle t and the preset phase shift ratio k t .

[0070] By reasonably configuring the target switching frequency f through the given value of the external phase shift angle min and the minimum switching frequency f t the given value of the external phase shift angle can be made linearly related to the actual alternating current i g to facilitate based on the given value of the external phase shift angle​ Control the actual alternating current i g .

[0071] According to the preset phase shift ratio k and the given value of the external phase shift angle Obtain the target internal phase shift angle φ t . The target internal phase shift angle φ t Can change with the given value of the external phase shift angle , so that it can be dynamically adjusted according to the given value of the external phase shift angle , improving the stability of the control of the dual active bridge converter 10.

[0072] Step S600: According to the given value of the external phase shift angle The target switching frequency f t And the target internal phase shift angle φ t Generate a driving signal, which is used to control the dual active bridge converter 10 to perform energy conversion.

[0073] The given value of the external phase shift angle The target switching frequency f t And the target internal phase shift angle φ t Can be provided to the controller 60, so that the controller 60 is based on the given value of the external phase shift angle The target switching frequency f t And the target internal phase shift angle φ t Adjust and control the dual active bridge converter 10 to output the corresponding current. Among them, the driving signal can be a PWM signal for controlling each switching device in the dual active bridge converter 10. The controller 60 is based on the given value of the external phase shift angle The target switching frequency f t And the target internal phase shift angle φ t The specific implementation of generating the driving signal can adopt the known methods in the art, and will not be introduced in detail here.

[0074] To sum up, since the feedforward value of the external phase shift angle Is obtained according to the target alternating current i g_ref , the actual DC voltage V dc , the minimum switching frequency f min And the circuit parameters of the transformer 200, the adjustment value of the external phase shift angle Is obtained according to the target alternating current i g_ref And the actual alternating current i g , so when the target alternating current i g_ref Is determined, the direction of the target alternating current i g_ref Is determined, that is, its positive and negative signs are determined. Therefore, when the target alternating current i g_refWhen there is symbolic property, the feed-forward value of the external phase-shifting angle also retains the symbolic property that can be positive or negative, ensuring the feed-forward value of the external phase-shifting angle has continuous adjustability. Therefore, according to the feed-forward value of the external phase-shifting angle and the adjustment value of the external phase-shifting angle, the given value of the external phase-shifting angle also has symbolic property. At this time, the symbolic property of the given value of the external phase-shifting angle is consistent with the symbolic property of the target alternating current i g_ref When the given value of the external phase-shifting angle and the adjustment amount determined by closed-loop control jointly determine the given value of the external phase-shifting angle After that, the target internal phase-shifting angle φ t can be jointly determined according to the given value of the external phase-shifting angle and the preset phase-shifting ratio k, thereby ensuring that the given value of the external phase-shifting angle has a linear relationship with the target alternating current i g_ref The given value of the external phase-shifting angle can change with the target power supply current i g_ref changes.

[0075] After generating the drive signal according to the given value of the external phase-shifting angle the target switching frequency f t and the target internal phase-shifting angle φ t When the dual-active-bridge converter 10 performs energy conversion according to the generated drive signal, especially during the process of energy direction switching, due to the given value of the external phase-shifting angle has a corresponding relationship with the flowing direction of energy. Therefore, based on the target alternating current i g_ref through the given value of the external phase-shifting angle the actual alternating current i g output can be smoothly and actively adjusted at the moment of switching the flowing direction of energy, and the purpose of reducing the oscillation of the output current or voltage waveform of the dual-active-bridge converter 10 can be achieved.

[0076] In an embodiment, the circuit parameters of the transformer 200 include the turns ratio n of the primary and secondary sides and the leakage inductance L of the secondary side k Step S200 includes determining the feed-forward value of the external phase-shifting angle of the dual-active-bridge converter 10 according to the actual DC voltage V dc the leakage inductance L of the secondary side k the turns ratio n of the primary and secondary sides, the minimum switching frequency f min and the target alternating current i g_ref Specifically, the feed-forward value of the external phase-shifting angle

[0077] ​is positively correlated with the minimum switching frequency f min The feedforward value of the external phase-shifting angle is positively correlated with the target alternating current i g_ref The feedforward value of the external phase-shifting angle is negatively correlated with the actual DC voltage V dc and the primary-secondary turns ratio n, and is positively correlated with the secondary leakage inductance L k Since the feedforward value of the external phase-shifting angle is related to the minimum switching frequency f min , the target alternating current i g_ref , the actual DC voltage V dc , the secondary leakage inductance L k and the primary-secondary turns ratio n have a mapping relationship, so when the minimum switching frequency f min , the actual DC voltage V dc , the secondary leakage inductance L k and the primary-secondary turns ratio n are known fixed values, there is a linear relationship between the feedforward value of the external phase-shifting angle and the target alternating current i g_ref In some embodiments, the calculation formula for the actual alternating current i g output by the dual-active-bridge converter 10 is:

[0078]

[0079] It should be noted that in Equation (1), is the external phase-shifting angle of the dual-active-bridge converter 10, f is the switching frequency of the switching device of the dual-active-bridge converter 10. n is the primary-secondary turns ratio; V dc is the actual DC voltage, L k is the secondary leakage inductance, and k is the phase-shift ratio.

[0080] In some embodiments, the phase-shift ratio k is usually taken as 0.2.

[0081] In one embodiment, the switching frequency f can be expressed as follows:

[0082]

[0083] Therefore, Equation (1) can be simplified according to Equation (2) as:

[0084]

[0085] Based on the relationship between the actual alternating current i g and the external phase-shifting angle in Equation (3), let the actual alternating current i g be the target alternating current i g_ref , then the target alternating current i can be obtainedg_ref is the independent variable, the feedforward value of the external phase shift angle is the relational expression of the dependent variable:

[0086]

[0087] When the DC voltage on the DC side is fixed, the leakage inductance L of the secondary side k , the actual DC voltage V dc , the turns ratio n of the primary and secondary sides, and the minimum switching frequency f min can all be regarded as constants. Therefore, according to Equation (4), it can be known that the feedforward value of the external phase shift angle and the target AC current i g_ref have a linear relationship. Since the target AC current i g_ref has a sign, the feedforward value of the external phase shift angle also has a sign that can be positive or negative, and when the sign of the target AC current i g_ref changes, the sign of the feedforward value of the external phase shift angle can change in real time with the sign of the target AC current i g_ref , ensuring the continuous adjustability of the feedforward value of the external phase shift angle .

[0088] In some embodiments, as Figure 5 shown, step S200 includes steps S210 to S220.

[0089] Step S210: Determine the proportionality coefficient S1 according to the actual DC voltage V dc , the leakage inductance L of the secondary side k and the turns ratio n of the primary and secondary sides.

[0090] Step S220: Determine the feedforward value of the external phase shift angle of the dual-active-bridge converter according to the minimum switching frequency f min , the target AC current i g_ref and the proportionality coefficient S1

[0091] Based on the actual DC voltage V dc , the leakage inductance L of the secondary side k , the turns ratio n of the primary and secondary sides, the proportionality coefficient S1 is obtained. Finally, according to the minimum switching frequency f min , the target AC current i g_ref and the proportionality coefficient S1, the feedforward value of the external phase shift angle

[0092] In one embodiment, the feedforward value of the external phase shift angle is positively correlated with the minimum switching frequency f min . The feedforward value of the external phase shift angle Is positively correlated with the target alternating current i g_ref The feed-forward value of the external phase-shifting angle Is positively correlated with the proportionality coefficient S1. That is, the minimum switching frequency f min The larger the value, the larger the feed-forward value of the external phase-shifting angle The larger the target alternating current i g_ref The larger the value, the larger the feed-forward value of the external phase-shifting angle The larger the value, the larger the proportionality coefficient S1, the larger the feed-forward value of the external phase-shifting angle The larger the value.

[0093] It should be noted that when the feed-forward value of the external phase-shifting angle Is positively correlated with the minimum switching frequency f min The target alternating current i g_ref And the proportionality coefficient S1, since the proportionality coefficient S1 and the minimum switching frequency f min Usually do not change during the operation of the dual-active-bridge converter 10. Therefore, during the operation of the dual-active-bridge converter 10, the feed-forward value of the external phase-shifting angle Is actually usually determined by the target alternating current i g_ref There is a linear relationship between the feed-forward value of the external phase-shifting angle And the target alternating current i g_ref The sign of the feed-forward value of the external phase-shifting angle Is the same as the sign of the target alternating current i g_ref The sign of.

[0094] In one embodiment, the feed-forward value of the external phase-shifting angle Is negatively correlated with the actual DC voltage V dc The turns ratio n of the primary and secondary sides, and is positively correlated with the leakage inductance L of the secondary side k The relationship.

[0095] It can be understood that the feed-forward value of the external phase-shifting angle The specific relationship with the actual DC voltage V dc The turns ratio n of the primary and secondary sides and the leakage inductance L of the secondary side k Can be referred to Equation (4). The feed-forward value of the external phase-shifting angle Can decrease as the actual DC voltage V dc Or the turns ratio n of the primary and secondary sides increases. The feed-forward value of the external phase-shifting angle Can increase as the leakage inductance L of the secondary side k Increases. Therefore, the feed-forward value of the external phase-shifting angle Is negatively correlated with the actual DC voltage V dc The turns ratio n of the primary and secondary sides, and is positively correlated with the leakage inductance L of the secondary side k The relationship.

[0096] In some embodiments, such asFigure 6 As shown, step S210 includes steps S211 to S213.

[0097] Step S211: Obtain a first product according to the secondary leakage inductance L k and a preset constant. That is, multiplying the secondary leakage inductance L k by the preset constant can obtain the first product. Exemplarily, the preset constant can be 4, and the first product can be 4L k .

[0098] Step S212: Obtain a second product according to the actual DC voltage V dc and the turns ratio n of the primary and secondary sides. That is, multiplying the actual DC voltage V dc by the turns ratio n of the primary and secondary sides can obtain the second product. Exemplarily, the second product can be nV dc .

[0099] Step S213: Determine the proportionality coefficient S1 according to the ratio between the first product and the second product. That is, dividing the first product by the second product can obtain the proportionality coefficient S1. Exemplarily, the proportionality coefficient S1 can be

[0100] Based on steps S211 to S213, the calculation formula for the proportionality coefficient S1 can be obtained:

[0101]

[0102] At this time, equation (4) can be further simplified to:

[0103]

[0104] It should be noted that the turns ratio n of the primary and secondary sides, the actual DC voltage V dc , the secondary leakage inductance L k and the preset constant usually do not change during the operation of the dual-active-bridge converter 10 and can all be regarded as constants. Therefore, when calculating the feedforward value of the external phase shift angle , the proportionality coefficient S1 can be regarded as a constant, so that the execution speed of the control method and the response speed of the dual-active-bridge converter 10 can be improved by simplifying the calculation formula.

[0105] In one embodiment, as Figure 7 shown, step S300 includes steps S310 to S320.

[0106] Step S310: Obtain the difference according to the target AC current i g_ref and the actual AC current i g .

[0107] It can be understood that subtracting the actual AC current i g_refThe difference obtained by subtracting the actual alternating current i g reflects the difference between the actual alternating current i g and the target alternating current i g_ref so as to determine the external phase shift angle according to the difference between the two The greater the difference between the two, the greater the adjustment range of the external phase shift angle is.

[0108] Step S320: Perform a deviation operation on the difference to obtain the adjustment value of the external phase shift angle

[0109] After obtaining the difference between the target alternating current i g_ref and the actual alternating current i g a deviation operation can be performed to obtain the adjustment value of the external phase shift angle

[0110] For example, the difference can be subjected to a deviation operation through a proportional-integral (PI) control algorithm to obtain the adjustment value of the external phase shift angle

[0111] The adjustment value of the external phase shift angle calculated through the above PI control algorithm can be used to adjust the set external phase shift angle of the dual active bridge converter 10 to achieve closed-loop control of the external phase shift angle so that the actual output can be as close as possible to the target output.

[0112] It can be understood that in addition to the above closed-loop control, the adjustment value of the external phase shift angle can also be obtained through other control methods This embodiment does not limit the specific control method.

[0113] In one embodiment, step S400 specifically includes: summing the feedforward value of the external phase shift angle and the adjustment value of the external phase shift angle to obtain the given value of the external phase shift angle

[0114] It should be noted that after the given value of the external phase shift angle is provided to the dual active bridge converter 10, the dual active bridge converter 10 can modify the set external phase shift angle of the dual active bridge converter 10 according to the given value of the external phase shift angle and perform corresponding energy conversion according to the modified external phase shift angle

[0115] ​​Due to the feed-forward value of the external phase-shift angle which is actually determined by the target AC current i g_ref therefore, the given value of the external phase-shift angle obtained from the feed-forward value of the external phase-shift angle can also vary according to the target AC current i g_ref The given value of the external phase-shift angle can have the same sign as the target AC current i g_ref Therefore, during the process of energy direction switching, based on the given value of the external phase-shift angle the actual AC current i g can be actively regulated at the instant of switching the energy flow direction, reducing the output voltage or current waveform jitter when the dual-active-bridge converter 10 switches the energy flow direction, and at the same time making the actual AC current i g output by the dual-active-bridge converter 10 as consistent as possible with the target AC current i g_ref

[0116] In one embodiment, as Figure 8 shown, step S500 includes steps S510 to S520.

[0117] Step S510: Multiply the absolute value of the given value of the external phase-shift angle by a preset phase-shift ratio k to obtain the target internal phase-shift angle φ t .

[0118] Specifically, the relationship formula of the target internal phase-shift angle φ t is:

[0119]

[0120] Given the known value of the given value of the external phase-shift angle , the target internal phase-shift angle φ can be obtained based on the phase-shift ratio k and the absolute value of the given value of the external phase-shift angle t .

[0121] Step S520: Determine the target switching frequency f min according to the minimum switching frequency f , the preset phase-shift ratio k, and the given value of the external phase-shift angle t .

[0122] Based on Equation (2), the relationship between the minimum switching frequency f min , the preset phase-shift ratio k, and the given value of the external phase-shift angle and the target switching frequency f t can be obtained:

[0123] ​

[0124] When the switching frequency f of the switching devices in the dual-active-bridge converter 10 is equal to the target switching frequency f t it is possible to make the actual AC current i g have a linear relationship with the given value of the external phase-shift angle so that the actual AC current i can be linearly regulated by controlling the given value of the external phase-shift angle g Moreover, since the given value of the external phase-shift angle has the same sign as the target AC current i g_ref there is a corresponding relationship between the sign of the given value of the external phase-shift angle and the direction of energy flow. Therefore, based on the target AC current i g_ref the actual AC current i can be actively regulated at the moment of switching the direction of energy flow by the given value of the external phase-shift angle g so that the actual AC current i g is as consistent as possible with the target AC current i g_ref and the mutation and oscillation of the actual AC current i g can be reduced when the dual-active-bridge converter 10 switches the direction of energy flow.

[0125] In one embodiment, the target switching frequency f t is positively correlated with the minimum switching frequency f min The target switching frequency f t is negatively correlated with the absolute value of the given value of the external phase-shift angle

[0126] Specifically, the relationship between the target switching frequency f t the minimum switching frequency f min and the absolute value of the given value of the external phase-shift angle is shown in Equation (8). The larger the minimum switching frequency f min the larger the target switching frequency f t The larger the absolute value of the given value of the external phase-shift angle the smaller the target switching frequency f t

[0127] In summary, in one embodiment, the control block diagram of the control method is as shown in Figure 9 By inputting the proportional coefficient S1 (i.e., ), the minimum switching frequency f min and the target AC current i g_ref into the corresponding multiplier and multiplying them, the feedforward value ​​

[0128] Actual alternating current i g The difference obtained by subtracting from the target alternating current i g_ref reflects the influence of objective factors on the actual alternating current i g , and based on the difference, the adjustment value of the external phase shift angle can be obtained through the PI control algorithm It can be understood that deviation control of the difference can also adopt other closed-loop control methods, not limited to the PI control method

[0129] Finally, the given value of the external phase shift angle can be obtained by adding the feedforward value of the external phase shift angle and the adjustment value of the external phase shift angle and based on the given value of the external phase shift angle the target switching frequency f t and the target internal phase shift angle φ t can be obtained to generate a drive signal for controlling the actual alternating current i according to the given value of the external phase shift angle t the target switching frequency f t and the target internal phase shift angle φ g

[0130] Since the target alternating current i g_ref has symbolic property, the feedforward value of the external phase shift angle also retains the symbolic property of being positive or negative, which ensures the continuous adjustability of the feedforward value of the external phase shift angle . The symbolic property of the feedforward value of the external phase shift angle will also make the given value of the external phase shift angle consistent with the target alternating current i g_ref . The symbolic property of the given value of the external phase shift angle will also affect the actual alternating current i g , and since the given value of the external phase shift angle has a corresponding relationship with the energy flow direction, finally, when the energy flow direction is switched, the actual alternating current i g can be actively controlled to reduce the fluctuations and oscillations of the actual alternating current i g , thereby reducing the fluctuations and oscillations of the relevant electrical signals

[0131] In the waveform diagram of the dual-active-bridge converter 10 controlled by the traditional method as shown in Figure 10A , the traditional method is used to control the energy direction switching Figure 10A From top to bottom in, they are the actual output voltage V g and the actual output current I g ​, waveforms of the switching frequency f_kHz and the internal phase shift angle φ (phi_capital). In the traditional method, when using the primary side phase shift angle to control the bidirectional switching, forced switching needs to be performed according to the power reference symbol, so that the forced switching energy direction will cause a step change in the loop output. As shown at points B and C in Figure 10A , the frequency (f_kHz) and the internal phase shift angle φ (phi_capital) will mutate. As shown at point A in Figure 10A , it will further cause oscillations in the output current I of the dual active bridge converter 10. g

[0132] As shown in the waveform diagram of the dual active bridge converter 10 controlled by the control method of the embodiment of the present application in Figure 10B , after controlling the dual active bridge converter 10 based on the external phase shift angle, referring to points B and C in Figure 10B , it can be seen that the frequency (f_kHz) and the internal phase shift angle (phi_capital) do not mutate, and it will not affect the waveform of the actual output current I of the dual active bridge converter 10. g

[0133] Figure 11 The schematic diagram of the control device of the dual active bridge converter provided by an embodiment of the present application is shown. For the convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0134] The control device 70 includes: an acquisition module 71, a first conversion module 72, a second conversion module 73, a third conversion module 74, a fourth conversion module 75, and a driving module 76.

[0135] The acquisition module 71 is used to acquire the actual alternating current i of the dual active bridge converter 10 as described in any one of the above embodiments. g , the target alternating current i. g_ref , the actual direct current voltage V. dc and the minimum switching frequency f. min

[0136] The first conversion module 72 is used to determine the feedforward value of the external phase shift angle of the dual active bridge converter 10 according to the target alternating current i. g_ref , the actual direct current voltage V. dc , the minimum switching frequency f. min and the circuit parameters of the transformer 200.

[0137] The second conversion module 73 is used to determine the adjustment value of the external phase shift angle according to the target alternating current i. g_ref and the actual alternating current i. g

[0138] The third conversion module 74 is configured to determine a given value of the external phase shift angle according to the feed-forward value of the external phase shift angle and the adjustment value of the external phase shift angle

[0139] The fourth conversion module 75 is configured to determine a target switching frequency f min and a target internal phase shift angle φ according to the minimum switching frequency f the given value of the external phase shift angle t and a preset phase shift ratio k t .

[0140] The driving module 76 is configured to generate a driving signal according to the given value of the external phase shift angle the target switching frequency f t and the target internal phase shift angle φ t The driving signal is used to control the dual-active-bridge converter 10 to perform energy conversion

[0141] In some embodiments, the first conversion module 72 includes a first calculation unit and a second calculation unit

[0142] The first calculation unit is configured to determine a proportionality coefficient S1 according to the actual DC voltage V dc the leakage inductance L of the secondary side k the turns ratio n of the primary side to the secondary side, and a preset constant

[0143] The second calculation unit is configured to determine the feed-forward value of the external phase shift angle of the dual-active-bridge converter 10 according to the minimum switching frequency f min the target AC current i g_ref and the proportionality coefficient S1

[0144] In some embodiments, the first calculation unit includes a first calculation subunit, a second calculation subunit, and a third calculation subunit

[0145] The first calculation subunit is configured to obtain a first product according to the leakage inductance L of the secondary side k and a preset constant

[0146] The second calculation subunit is configured to obtain a second product according to the actual DC voltage V dc and the turns ratio n of the primary side to the secondary side

[0147] The third calculation subunit is configured to determine the proportionality coefficient S1 according to the ratio between the first product and the second product

[0148] In some embodiments, the second conversion module 73 includes a third calculation unit and a fourth calculation unit

[0149] The third calculation unit is configured to determine according to the target AC current ig_ref and the actual alternating current i g to obtain a difference value.

[0150] The fourth calculation unit is used to perform a deviation operation on the difference value to obtain an adjustment value of the external phase shift angle

[0151] In some embodiments, the fourth conversion module 75 includes a fifth calculation unit and a sixth calculation unit.

[0152] The fifth calculation unit is used to multiply the absolute value of the given value of the external phase shift angle by a preset phase shift ratio k to obtain a target internal phase shift angle φ t .

[0153] The sixth calculation unit is used to determine the target switching frequency f according to the minimum switching frequency f min , the preset phase shift ratio k, and the absolute value of the given value of the external phase shift angle to obtain the target switching frequency f t .

[0154] For the specific implementation manners and related beneficial effects of the control device 80 of the dual-active-bridge converter 10 described above, please refer to the description of the specific embodiments of the control method of the dual-active-bridge converter 10 above, which will not be elaborated here.

[0155] Figure 12 The following shows a schematic diagram of an energy storage device provided by an embodiment of the present application. For the convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0156] The energy storage device 80 includes a dual-active-bridge converter 10 according to any one of the above embodiments, a memory 82, a processor 81, and a computer program 821 stored in the memory 82 and executable on the processor 81. The processor 81 is connected to the dual-active-bridge converter 10. When the processor 81 executes the computer program 821, it implements the control method of the dual-active-bridge converter 10 according to any one of the above embodiments.

[0157] In some embodiments, the energy storage device 80 further includes an energy storage module such as a battery pack. The energy storage module is connected to the dual-active-bridge converter 10 and is used to store or output direct current.

[0158] In some embodiments, the energy storage device 80 further includes a power generation module such as a photovoltaic power generation device. The power generation module is connected to the dual-active-bridge converter 10 and is used to output direct current.

[0159] Among them, the processor 81 may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0160] The memory 82 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or may also be an Electrically Erasable Programmable Read-Only Memory (EEPROM), a Compact Disc Read-Only Memory (CD-ROM), or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0161] Figure 13 The schematic diagram of the storage of the computer-readable storage medium provided by an embodiment of the present application is shown. For the convenience of description, only the part related to this embodiment is shown and is described in detail as follows:

[0162] The computer-readable storage medium 90 stores a computer program. When the computer program is executed by the controller 60, the steps of the control method of the dual-active-bridge converter 10 in any of the above embodiments are implemented.

[0163] The computer-readable storage medium 90 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or may also be an Electrically Erasable Programmable Read-Only Memory (EEPROM), a Compact Disc Read-Only Memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0164] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0165] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiments and will not be described in detail here.

[0166] In the above embodiments, each embodiment is described with its own emphasis. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0167] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A control method for a dual active bridge converter, characterized in that: The dual active bridge converter comprises a DC side bridge circuit, a transformer and an AC side bridge circuit, wherein a first end of the DC side bridge circuit is connected to a primary side of the transformer, a second end of the DC side bridge circuit is used to connect at least one of a DC power supply and a DC load, a secondary side of the transformer is connected to a first end of the AC side bridge circuit, and a second end of the AC side bridge circuit is used to connect at least one of a power grid and an AC load; the control method comprises: Obtaining an actual AC current, a target AC current, an actual DC voltage and a minimum switching frequency of the dual active bridge converter; Determining a feedforward value of an external phase shift angle of the dual active bridge converter according to the target AC current, the actual DC voltage, the minimum switching frequency and the circuit parameters of the transformer; Determining an adjustment value of the external phase shift angle according to the target alternating current and the actual alternating current; Determining a given value of the external phase shift angle according to the feedforward value of the external phase shift angle and the adjustment value of the external phase shift angle; Determining a target switching frequency and a target inner phase shift angle according to the minimum switching frequency, a given value of the outer phase shift angle, and a preset phase shift ratio; A drive signal is generated according to the given value of the outer phase shift angle, the target switching frequency and the target inner phase shift angle, and the drive signal is used to control the dual active bridge converter to perform energy conversion.

2. The control method according to claim 1, characterized in that: The circuit parameters of the transformer include a primary-to-secondary turns ratio and a secondary-side leakage inductance; the feedforward value of the external phase angle of the dual active bridge converter is determined according to the target AC current, the actual DC voltage, the minimum switching frequency and the circuit parameters of the transformer, including: A feedforward value of an external phase angle of the dual active bridge converter is determined according to the actual DC voltage, the secondary leakage inductance, the primary-to-secondary turns ratio, the minimum switching frequency, and the target AC current.

3. The control method according to claim 2, characterized in that: The feedforward value of the external phase shift angle is positively correlated with the minimum switching frequency; the feedforward value of the external phase shift angle is positively correlated with the target alternating current.

4. The control method according to claim 2, characterized in that: The feedforward value of the external phase angle is negatively correlated with the actual DC voltage and the primary-to-secondary turns ratio, and is positively correlated with the secondary leakage inductance.

5. The control method according to claim 1, characterized in that: The step of determining the adjustment value of the external phase shift angle according to the target alternating current and the actual alternating current includes: Obtaining a difference value according to the target alternating current and the actual alternating current; A deviation operation is performed on the difference to obtain an adjustment value of the external shift phase angle.

6. The control method according to claim 1, characterized in that: Determining the given value of the external phase shift angle according to the feedforward value of the external phase shift angle and the adjustment value of the external phase shift angle includes: The feedforward value of the external phase shift angle and the adjustment value of the external phase shift angle are summed to obtain a given value of the external phase shift angle.

7. The control method according to claim 1, characterized in that: Determining a target switching frequency and a target inner phase shift angle according to the minimum switching frequency, the given value of the outer phase shift angle, and a preset phase shift angle includes: Obtaining the target inner phase shift angle according to the product of the absolute value of the given value of the outer phase shift angle and the preset phase shift angle; The target switching frequency is determined according to the minimum switching frequency, the preset phase shift angle, and a given value of the external phase shift angle.

8. The control method according to claim 7, characterized in that: The target switching frequency is positively correlated with the minimum switching frequency; the target switching frequency is negatively correlated with the absolute value of the given value of the external shift phase angle.

9. An energy storage device, characterized in that: The invention comprises a dual active bridge converter, a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the dual active bridge converter comprises a DC side bridge circuit, a transformer and an AC side bridge circuit, wherein a first end of the DC side bridge circuit is connected to a primary side of the transformer, a second end of the DC side bridge circuit is used to connect at least one of a DC power supply and a DC load, a secondary side of the transformer is connected to a first end of the AC side bridge circuit, and a second end of the AC side bridge circuit is used to connect at least one of a power grid and an AC load, the processor is connected to the dual active bridge converter, and when the processor executes the computer program, the control method of the dual active bridge converter according to any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by the controller, the steps of the control method of the dual active bridge converter according to any one of claims 1 to 8 are implemented.

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