Light load optimization control method and system for double-active-bridge series resonant converter

Abstract

The invention relates to a light load optimization control method and system for a dual-active bridge series resonant converter, and the method comprises the steps: obtaining a first load current reference value of a second port and the actual output power of a third port, and converting the actual output power of the third port into a second load current reference value of the second port, determining the sum of the first load current reference value and the second load current reference value as a target load current reference value; if it is determined that the dual-active-bridge series resonant converter enters the light-load working condition, obtaining an external shift phase angle adjustment value based on a target load current reference value and a preset fitting relation; based on the external phase shift angle adjustment value, adjusting an external phase shift angle between a full bridge where the first port is located and a full bridge where the second port is located, and adjusting an internal phase shift angle of the full bridge where the first port is located and a switching period of the dual-active bridge series resonant converter; according to the method, light load optimization control of a three-port circuit, namely a double-active-bridge series resonance three-port converter, can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of converters, and in particular to a light-load optimization control method and system for a dual-active-bridge series resonant converter. Background Art

[0002] Dual Active Bridge Series Resonant Converters (DBSRCs) have been widely used in electric vehicle charging, energy storage systems, and data center power supplies due to their advantages such as electrical isolation, bidirectional power transmission, and soft switching. However, in practical engineering applications, especially under special operating conditions such as high-voltage and light-load output, DBSRCs still face certain technical challenges.

[0003] Under the special operating condition of high-voltage and light-load output, the switching devices in the primary full-bridge of the dual-active-bridge series resonant converter have problems such as large hard-on current, large turn-on loss, and high temperature rise rate, which lead to reduced converter performance and great thermal risks. Summary of the Invention

[0004] The present invention provides a light-load optimization control method and system for a dual-active-bridge series resonant converter, so as to solve the problems in the prior art of large hard-on current and high temperature rise rate of switching devices in the primary full bridge of the dual-active-bridge series resonant converter under high-voltage light-load output conditions.

[0005] The present invention provides a light-load optimization control method for a dual-active bridge series resonant converter, which is applied to a three-port circuit. The three-port circuit includes: a first port, a second port, and a third port. The method includes:

[0006] obtaining a first load current reference value of the second port and an actual output power of the third port, converting the actual output power of the third port into a second load current reference value of the second port, and determining a sum of the first load current reference value and the second load current reference value as a target load current reference value;

[0007] If it is determined that the dual active bridge series resonant converter enters a light load operating condition, then based on the target load current reference value and a preset fitting relationship, an external phase shift angle adjustment value corresponding to the target load current reference value is obtained;

[0008] Based on the external phase angle adjustment value, the external phase angle between the full bridge where the first port is located and the full bridge where the second port is located is adjusted, and by adjusting the internal phase angle of the full bridge where the first port is located and the switching period of the dual active bridge series resonant converter, the light load optimization control of the dual active bridge series resonant converter is completed.

[0009] In some embodiments of the present invention, converting the actual output power of the third port into a second load current reference value of the second port includes:

[0010] Obtaining the output voltage and output current of the third port;

[0011] determining the product of the output voltage and the output current of the third port as the actual output power of the third port;

[0012] Determine an intermediate power by a ratio between the actual output power of the third port and a preset conversion efficiency, wherein the intermediate power is the power transmitted from the third port to the second port;

[0013] Obtaining an actual value of the output voltage of the second port;

[0014] A ratio between the intermediate power and the actual value of the output voltage is determined as the second load current reference value.

[0015] In some embodiments of the present invention, determining that the dual active bridge series resonant converter enters a light load condition includes:

[0016] Acquire voltage-related information, where the voltage-related information includes: an actual value of the input voltage of the first port and an actual value of the output voltage of the second port;

[0017] Obtaining a load boundary value corresponding to the voltage-related information according to a preset boundary fitting relationship and the voltage-related information, wherein the boundary fitting relationship is a fitting relationship between the voltage-related information and the load boundary value, and the load boundary value is a value of a load current output by the second port when the dual active bridge series resonant converter enters a light-load operating condition;

[0018] Obtaining an actual value of the load current output by the second port;

[0019] When the actual value of the load current drops to the load threshold value, it is determined that the dual active bridge series resonant converter enters a light load condition.

[0020] In some embodiments of the present invention, obtaining the boundary fitting relationship includes:

[0021] Acquiring a plurality of sample point information, the sample point information including: corresponding input voltage sample values, output voltage sample values, and load boundary sample values, the output voltage sample values ​​being sample values ​​of the voltage output by the second port, and the load boundary sample values ​​being sample values ​​of the load current output by the second port when the dual active bridge series resonant converter enters a light load condition;

[0022] sorting the plurality of sample point information according to the magnitude of the input voltage sample value or the magnitude of the output voltage sample value to obtain a sample point sequence;

[0023] If the input voltage sample values ​​of a plurality of consecutive sample point information in the sample point sequence are the same, the sample point information with the same input voltage sample value is determined as the first sample point information, and the remaining sample point information is determined as the second sample point information;

[0024] Fitting is performed on the first sample point information and the second sample point information respectively to obtain the boundary fitting relationship.

[0025] In some embodiments of the present invention, fitting the first sample point information and the second sample point information respectively to obtain the boundary fitting relationship includes:

[0026] Determine the ratio between the output voltage sample value and the input voltage sample value in the first sample point information as a first independent variable, and determine the load boundary sample value in the first sample point information as a first dependent variable;

[0027] Performing fitting based on the first independent variable and the first dependent variable to obtain a first fitting relationship;

[0028] obtaining a proportional relationship between input voltage sample values ​​and output voltage sample values ​​in a plurality of second sample point information; determining a ratio between the output voltage sample value and the input voltage sample value in the second sample point information as an intermediate independent variable; and based on the proportional relationship, replacing the input voltage sample value in the intermediate independent variable with an expression containing the corresponding output voltage sample value to obtain a second independent variable; and determining the load boundary sample value in the first sample point information as a second dependent variable;

[0029] Performing fitting based on the second independent variable and the second dependent variable to obtain a second fitting relationship;

[0030] The first fitting relationship and the second fitting relationship are determined as the boundary fitting relationship.

[0031] In some embodiments of the present invention, determining the preset fitting relationship includes:

[0032] Acquire a plurality of information to be fitted, wherein the information to be fitted includes mutually corresponding load current sample values ​​and external phase shift angle sample values;

[0033] A cubic polynomial fitting is performed on the information to be fitted to obtain the preset fitting relationship, where the independent variable in the preset fitting relationship is the load current sample value, and the dependent variable in the preset fitting relationship is the external shift phase angle sample value.

[0034] In some embodiments of the present invention, obtaining the first load current reference value includes:

[0035] Obtaining an actual input current value of the first port and a preset input current limit value;

[0036] Performing a proportional-integral operation based on a difference between the actual input current value and the input current limit value to obtain a first current value;

[0037] Acquire an actual output voltage value and an output voltage command value of the second port, where the output voltage command value refers to the output voltage value of the second port in the control instruction received by the dual active bridge series resonant converter;

[0038] Performing a proportional-integral operation based on a difference between the actual output voltage value and the output voltage command value to obtain a second current value;

[0039] Obtaining a third current value, where the third current value refers to an output current value of the second port in the control instruction;

[0040] A minimum value among the first current value, the second current value, and the third current value is determined as the first load current reference value.

[0041] In some embodiments of the present invention, light-load optimization control of the dual active bridge series resonant converter is performed by adjusting the internal phase shift angle of the full bridge where the first port is located and the switching period of the dual active bridge series resonant converter, including:

[0042] Obtaining an actual value of the load current of the second port;

[0043] Performing a proportional-integral operation based on a difference between the first load current reference value and the actual load current value to obtain a first switching period;

[0044] performing a proportional resonance operation according to the first switching period to obtain a second switching period;

[0045] If the second switching period is within a preset switching period threshold range, the second switching period is determined as the switching period adjustment value, and the preset inner phase shift angle value is determined as the inner phase shift angle adjustment value;

[0046] If the second switching period is less than a minimum value in the switching period threshold range and the second switching period is greater than 0, the minimum value in the switching period threshold range is determined as the switching period adjustment value, and a ratio between the second switching period and twice the switching period adjustment value is determined as the inner phase shift angle adjustment value;

[0047] According to the switching period adjustment value and the inner phase shift angle adjustment value, the switching period and the switching period of the dual active bridge series resonant converter are adjusted to complete the control of the dual active bridge series resonant converter.

[0048] The present invention also provides a light-load optimization control system for a dual-active bridge series resonant converter, which is applied to a three-port circuit. The three-port circuit includes: a first port, a second port, and a third port. The system includes:

[0049] a target load current reference value determining module, configured to obtain a first load current reference value of the second port and an actual output power of the third port, convert the actual output power of the third port into a second load current reference value of the second port, and determine the sum of the first load current reference value and the second load current reference value as a target load current reference value;

[0050] an external phase angle adjustment value acquisition module, configured to obtain an external phase angle adjustment value corresponding to the target load current reference value based on the target load current reference value and a preset fitting relationship if it is determined that the dual active bridge series resonant converter enters a light load condition;

[0051] A light-load optimization control module is configured to adjust the external phase-shift angle between the full bridge where the first port is located and the full bridge where the second port is located based on the external phase-shift angle adjustment value, and to complete light-load optimization control of the dual-active-bridge series resonant converter by adjusting the internal phase-shift angle of the full bridge where the first port is located and the switching period of the dual-active-bridge series resonant converter.

[0052] The present invention also provides a dual active bridge series resonant converter, comprising a three-port circuit and the dual active bridge series resonant converter light load optimization control system as described above;

[0053] The dual-active-bridge series resonant converter light-load optimization control system controls the drive signals of multiple switching devices in the three-port circuit to adjust the external phase shift angle, internal phase shift angle, and switching period of the dual-active-bridge series resonant converter.

[0054] Beneficial effects of the present invention: The present invention provides a light-load optimization control method and system for a dual-active bridge series resonant converter. The method obtains a first load current reference value of the second port and an actual output power of the third port, converts the actual output power of the third port into a second load current reference value of the second port, and determines the sum of the first load current reference value and the second load current reference value as a target load current reference value; if it is determined that the dual-active bridge series resonant converter enters a light-load operating condition, an external phase angle adjustment value corresponding to the target load current reference value is obtained based on the target load current reference value and a preset fitting relationship; based on the external phase angle adjustment value, the external phase angle between the full bridge where the first port is located and the full bridge where the second port is located is adjusted, and the internal phase angle of the full bridge where the first port is located and the switching period of the dual-active bridge series resonant converter are adjusted to complete the light-load optimization control of the dual-active bridge series resonant converter. This method can effectively implement light-load optimization control for a three-port circuit, namely, a dual-active-bridge series resonant three-port converter. When the converter enters a light-load condition, it can adjust the external phase shift angle, the internal phase shift angle, and the switching period to reduce the hard-on current of the switching devices in the primary full bridge (the full bridge where the first port is located) under light-load conditions or high-voltage light-load output conditions, thereby avoiding excessive temperature rise rates and ensuring the overall performance and efficiency of the converter at a low cost. Furthermore, by converting or converting the actual output power of the third port into a second load current reference value for the second port, the light-load optimization control accuracy of the three-port circuit can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic flow chart of a light-load optimization control method for a dual active bridge series resonant converter provided by one embodiment of the present invention;

[0056] Figure 2 An example diagram of the relationship between the external phase shift angle and the target load current reference value when the external phase shift angle light load optimization is not performed according to an embodiment of the present invention;

[0057] Figure 3 An example diagram of the relationship between the external phase shift angle and the target load current reference value under the condition of linear fitting of the external phase shift angle under light load provided by one embodiment of the present invention;

[0058] Figure 4 An example diagram of the relationship between the external phase shift angle obtained by fitting the external phase shift angle light-load cubic polynomial provided by one embodiment of the present invention and the target load current reference value;

[0059] Figure 5 A schematic diagram of a specific flow chart of a light-load optimization control method for a dual active bridge series resonant converter provided in one embodiment of the present invention;

[0060] Figure 6A schematic structural diagram of a light-load optimization control system for a dual-active-bridge series resonant converter according to an embodiment of the present invention;

[0061] Figure 7 A schematic structural diagram of a dual active bridge series resonant converter provided by one embodiment of the present invention;

[0062] Figure 8 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0064] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0065] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the embodiments of the present invention.

[0066] To facilitate understanding of the light-load optimization control method and system for a dual-active-bridge series resonant converter provided by the present invention, some technical terms involved in the present invention are explained below.

[0067] Dual active bridge series resonant converter: A power electronic converter based on a dual active bridge topology combined with series resonance. It has significant advantages in efficient power conversion, low switching losses, and high power density, and is widely used in fields requiring efficient energy transmission and conversion.

[0068] Light load condition: The output power of the dual active bridge series resonant converter is much lower than its rated power. In this case, soft switching (such as ZVS) may fail, increasing switching losses and reducing efficiency.

[0069] High-voltage, light-load output operating condition: This is the operating state of the dual-active-bridge series resonant converter operating at high output voltage and low output power. In this case, the hard-on current of the switching devices in the primary full-bridge increases, resulting in large turn-on losses, which affects efficiency and heat dissipation, posing a certain thermal risk.

[0070] Switching cycle: The time it takes for a complete switching action in a dual active bridge series resonant converter (such as the alternating conduction of the upper and lower tubes of the full bridge (H bridge)).

[0071] External phase angle: The phase difference between different full bridges, such as the phase difference between the primary full bridge (input side or active side full bridge) and the secondary full bridge (output side or passive side full bridge).

[0072] Internal phase shift angle: The phase difference between different switching devices (such as MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) and IGBT (Insulated Gate Bipolar Transistor)) within a single full-bridge.

[0073] Zero Voltage Switching (ZVS): A soft switching technology that significantly reduces switching losses and electromagnetic interference (EMI) by triggering the switching action when the voltage across the switching device is zero.

[0074] Hard-on current: The current flowing when a switching device is turned on or off under non-zero voltage (hard switching) conditions. This current causes significant switching losses and may cause voltage / current stress, as well as electromagnetic interference and other problems.

[0075] Please refer to Figure 1 , Figure 1 A flow chart of a light-load optimization control method for a dual active bridge series resonant converter according to an embodiment of the present invention is provided. The method is applied to a three-port circuit, wherein the three-port circuit includes: a first port, a second port, and a third port. Figure 1 As shown, the method includes:

[0076] S110: Obtain a first load current reference value of the second port and an actual output power of the third port, convert the actual output power of the third port into a second load current reference value of the second port, and determine the sum of the first load current reference value and the second load current reference value as a target load current reference value.

[0077] It should be noted that, through the above steps, a target load current reference value with high accuracy can be obtained, which helps to improve the light-load optimization control accuracy of the three-port circuit, i.e., the dual active bridge series resonant three-port converter.

[0078] S120: If it is determined that the dual active bridge series resonant converter enters the light load condition, an external phase angle adjustment value corresponding to the target load current reference value is obtained based on the target load current reference value and a preset fitting relationship.

[0079] S130: Based on the external phase angle adjustment value, the external phase angle between the full bridge where the first port is located and the full bridge where the second port is located is adjusted, and the internal phase angle of the full bridge where the first port is located and the switching period of the dual active bridge series resonant converter are adjusted to complete the light load optimization control of the dual active bridge series resonant converter.

[0080] In some examples of this embodiment, the external phase shift angle between the full bridge where the first port is located and the full bridge where the second port is located may be directly adjusted to the external phase shift angle adjustment value.

[0081] In some examples of this embodiment, a preset mapping relationship and a neural network model can be used to obtain the internal phase shift angle adjustment value and the switching period adjustment value of the dual active bridge series resonant converter, thereby adjusting the internal phase shift angle of the dual active bridge series resonant converter based on the internal phase shift angle adjustment value, and adjusting the switching period of the dual active bridge series resonant converter based on the switching period adjustment value. For example, a mapping relationship between a first load current reference value and a mapping value (including an internal phase shift angle and a switching period) is pre-set, and based on the mapping relationship, the corresponding internal phase shift angle adjustment value and the switching period adjustment value are obtained. Alternatively, the first load current reference value is input into a pre-trained neural network model to perform internal phase shift angle adjustment value prediction and switching period adjustment value prediction, thereby obtaining the internal phase shift angle adjustment value and the switching period adjustment value output by the neural network model.

[0082] It should be noted that the light-load optimization control method for the dual-active-bridge series resonant converter in the above embodiment can effectively reduce the hard-on current of the full-bridge where the first port is located by adjusting the external phase shift angle between the full-bridge where the first port is located and the full-bridge where the second port is located, the internal phase shift angle of the full-bridge where the first port is located, and the switching period of the dual-active-bridge series resonant converter. In addition, it can widen the ZVS turn-on range to a certain extent, reduce switching losses, and thus avoid problems such as temperature rise and thermal risks under high-voltage light-load output conditions. Widening the ZVS turn-on range means that by optimizing the control strategy and other means, the switching devices in the dual-active-bridge series resonant converter can achieve zero-voltage turn-on under wider load conditions, input voltage ranges, or parameter changes, thereby reducing switching losses and improving efficiency.

[0083] In some embodiments, converting the actual output power of the third port into a second load current reference value of the second port includes:

[0084] 1. Obtain the output voltage and output current of the third port.

[0085] 2. Determine the product of the output voltage and the output current of the third port as the actual output power of the third port.

[0086] 3. Determine an intermediate power by using a ratio between the actual output power of the third port and a preset conversion efficiency, where the intermediate power is the power transmitted from the third port to the second port.

[0087] 4. Obtain the actual value of the output voltage of the second port.

[0088] 5. Determine a ratio between the intermediate power and the actual value of the output voltage as the second load current reference value.

[0089] In some examples of this embodiment, the mathematical expression for obtaining the second load current reference value is:

[0090]

[0091] Among them, u Bnet Indicates the output voltage of the third port, i Bnet represents the output current of the third port, μ is the preset conversion efficiency, u Tnet Indicates the actual value of the output voltage of the second port.

[0092] It can be understood that, through the above method, the actual output power of the third port can be converted to the second load current reference value of the second port, thereby helping to improve the accuracy of subsequent external phase shift angle control.

[0093] In some embodiments, determining that the dual active bridge series resonant converter enters a light load condition includes:

[0094] 1. Obtain voltage-related information, where the voltage-related information includes: an actual value of the input voltage of the first port and an actual value of the output voltage of the second port.

[0095] 2. According to the preset boundary fitting relationship and the voltage association information, a load boundary value corresponding to the voltage association information is obtained, wherein the boundary fitting relationship is a fitting relationship between the voltage association information and the load boundary value, and the load boundary value is the value of the load current output by the second port when the dual active bridge series resonant converter enters a light load condition.

[0096] 3. Obtain the actual value of the load current output by the second port.

[0097] 4. When the actual value of the load current drops to the load threshold value, it is determined that the dual active bridge series resonant converter enters a light load condition.

[0098] It should be noted that, through the above steps, it is possible to monitor whether the dual active bridge series resonant converter is operating in a light load condition.

[0099] In some embodiments, obtaining the boundary fitting relationship includes:

[0100] 1. Acquire multiple sample point information, the sample point information including: corresponding input voltage sample values, output voltage sample values, and load boundary sample values, the output voltage sample values ​​being sample values ​​of the voltage output by the second port, and the load boundary sample values ​​being sample values ​​of the load current output by the second port when the dual active bridge series resonant converter enters a light load condition.

[0101] In some examples of this embodiment, the input voltage sample value and the output voltage sample value may be obtained through instrument detection, and the load boundary sample value may be obtained through experimental testing or manually set.

[0102] 2. Sort the plurality of sample point information according to the magnitude of the input voltage sample value or the magnitude of the output voltage sample value to obtain a sample point sequence.

[0103] 3. If the input voltage sample values ​​of a plurality of consecutive sample point information in the sample point sequence are the same, the sample point information with the same input voltage sample value is determined as the first sample point information, and the remaining sample point information is determined as the second sample point information.

[0104] 4. Fitting the first sample point information and the second sample point information respectively to obtain the boundary fitting relationship.

[0105] It should be noted that by fitting the first sample point information and the second sample point information separately, it is possible to obtain fitting relationships for both the cases where the input voltage sample values ​​are the same and the cases where the input voltage sample values ​​are different, thereby reducing the difficulty of fitting and improving the credibility and accuracy of the resulting boundary fitting relationship. It is understandable that, compared to fitting all sample point information, the above-mentioned segmented fitting method not only reduces the amount of data and the difficulty of fitting for a single fit, but also helps to improve the accuracy of the subsequently obtained boundary fitting relationship and improve the efficiency of subsequent reading or calling of the boundary fitting relationship.

[0106] In some embodiments, fitting the first sample point information and the second sample point information respectively to obtain the boundary fitting relationship includes:

[0107] 1. Determine the ratio between the output voltage sample value and the input voltage sample value in the first sample point information as a first independent variable, and determine the load boundary sample value in the first sample point information as a first dependent variable.

[0108] 2. Perform fitting based on the first independent variable and the first dependent variable to obtain a first fitting relationship.

[0109] 3. Obtain a proportional relationship between input voltage sample values ​​and output voltage sample values ​​in a plurality of second sample point information; determine a ratio between the output voltage sample values ​​and the input voltage sample values ​​in the second sample point information as an intermediate independent variable; and based on the proportional relationship, replace the input voltage sample values ​​in the intermediate independent variable with an expression containing corresponding output voltage sample values ​​to obtain a second independent variable; and determine the load boundary sample values ​​in the first sample point information as a second dependent variable.

[0110] 4. Perform fitting based on the second independent variable and the second dependent variable to obtain a second fitting relationship.

[0111] 5. Determine the first fitting relationship and the second fitting relationship as the boundary fitting relationship.

[0112] The following further explains how to obtain the above boundary fitting relationship by taking an exemplary dual active bridge series resonant converter as an example.

[0113] First, the operating range and component parameters of the exemplary dual active bridge series resonant converter can be referred to in Table 1 below:

[0114] Table 1 Operating range and component parameters of an exemplary dual active bridge series resonant converter

[0115]

[0116] Based on the parameters shown in Table 1, multiple experiments were conducted to obtain the following Table 2:

[0117] Table 2 Different voltage gains Load cutoff point below

[0118]

[0119] Among them, I TnetDiff Represents the load boundary (sample) value, that is, the load current value at the load boundary point, Indicates the corresponding outward shift phase angle at the load boundary point.

[0120] When V B =750V~880V(V A =800V), the mathematical expression of the first fitting relationship is:

[0121]

[0122] When V B =550V~750V(V A =700V~800V), we get V A and V B The proportional relationship between them:

[0123]

[0124] Simplifying, we get:

[0125] Then, the mathematical expression of the second fitting relationship is obtained as follows:

[0126]

[0127] It can be understood that the above method of obtaining the first fitting relationship and the second fitting relationship is simple to operate, low in cost, and low in computational difficulty.

[0128] In some embodiments, determining the preset fitting relationship includes:

[0129] 1. Acquire multiple pieces of information to be fitted, where the information to be fitted includes corresponding load current sample values ​​and external shift phase angle sample values.

[0130] 2. Performing cubic polynomial fitting on the information to be fitted to obtain the preset fitting relationship, wherein the independent variable in the preset fitting relationship is the load current sample value, and the dependent variable in the preset fitting relationship is the external shift phase angle sample value.

[0131] The following Table 3 exemplifies the information to be fitted in the above embodiment. Please refer to Table 3:

[0132] Table 3 Examples of information to be fitted

[0133]

[0134] Among them, I Tnet represents the actual value of the load current of the dual active bridge series resonant converter, f s is the preset switching frequency, Denotes the outward phase angle, D Arepresents the internal phase shift angle of the primary full bridge, x is the independent variable in the cubic polynomial fitting, y is the dependent variable in the cubic polynomial fitting, and " / " represents the relationship of "or". Performing cubic polynomial fitting on x and y in Table 3 yields:

[0135] y=3.3643x 3 -6.2553x 2 +3.9196x-0.0286

[0136] The above mathematical expression is the preset fitting relationship obtained by performing cubic polynomial fitting based on Table 3.

[0137] Figure 2 For an example diagram of the relationship between the external phase shift angle and the target load current reference value when the external phase shift angle light load optimization is not performed according to an embodiment of the present invention, please refer to Figure 2 , Figure 2 The horizontal axis is the target load current reference value i TnetRefConv , the vertical axis is the outward shift phase angle Figure 2 Take I TnetDiff Draw an auxiliary line perpendicular to the horizontal axis. The auxiliary line to the left is the light load range, and the auxiliary line to the right is the medium and heavy load range. When light load optimization is not performed, as the load current changes, the corresponding external shift phase angle remains unchanged, that is, it remains

[0138] Figure 3 For an example diagram of the relationship between the external phase shift angle and the target load current reference value under the condition of linear fitting of the external phase shift angle under light load provided by an embodiment of the present invention, please refer to Figure 3 , Figure 3 In the light load range, a linear fitting method is adopted, so that the load current reference value and the corresponding external shift phase angle in the light load range show a linear downward trend.

[0139] Figure 4 For an example diagram of the relationship between the external phase shift angle obtained by fitting the external phase shift angle light load cubic polynomial provided in one embodiment of the present invention and the target load current reference value, please refer to Figure 4 By fitting the external phase shift angle and the load current reference value in the light load range with a cubic polynomial, the external phase shift angle can be smoothly decreased in the light load range. Figure 2 The light-load optimization method of the external phase angle is not performed in the embodiment. The light-load cubic polynomial fitting method of the external phase angle in this embodiment can adjust the external phase angle under light-load conditions. Figure 3 In the linear fitting method, the light load cubic polynomial fitting method of the external phase shift angle in this embodiment can avoid the load boundary point (with I TnetDiff Draw an auxiliary line perpendicular to the horizontal axis. Figure 2 、 3, 4) the outward phase angle drops sharply, thus avoiding the impact on the efficiency of the converter. Figure 4 As shown in the figure, in addition to the light load range, there is also a continuous curve in the medium and heavy load range, namely the dark blue line parallel to the horizontal axis in the medium and heavy load range. It can be understood that through this method, a natural and smooth transition between light load and medium and heavy load can be achieved, which facilitates the overall efficiency optimization and improvement across the entire operating range.

[0140] In some embodiments, obtaining the first load current reference value includes:

[0141] 1. Obtaining the actual value of the input current of the first port and the preset input current limit value.

[0142] 2. Perform a proportional integral operation based on the difference between the actual input current value and the input current limit value to obtain a first current value.

[0143] 3. Obtaining an actual output voltage value and an output voltage command value of the second port, where the output voltage command value refers to the output voltage value of the second port in the control instruction received by the dual active bridge series resonant converter.

[0144] 4. Perform a proportional integral operation based on the difference between the actual output voltage value and the output voltage command value to obtain a second current value.

[0145] 5. Obtain a third current value, where the third current value refers to the output current value of the second port in the control instruction.

[0146] 6. Determine the minimum value among the first current value, the second current value, and the third current value as the first load current reference value.

[0147] It can be understood that through the above steps, a first load current reference value with higher accuracy can be obtained, which helps to improve subsequent control accuracy.

[0148] In some embodiments, adjusting the internal phase shift angle of the full bridge where the first port is located and the switching period of the dual active bridge series resonant converter to complete light load optimization control of the dual active bridge series resonant converter includes:

[0149] 1. Obtain an actual value of the load current of the second port.

[0150] 2. Perform a proportional-integral operation based on the difference between the first load current reference value and the actual load current value to obtain a first switching period.

[0151] 3. Perform proportional resonance operation according to the first switching period to obtain a second switching period.

[0152] 4. If the second switching period is within a preset switching period threshold range, the second switching period is determined as the switching period adjustment value, and the preset inner phase shift angle value is determined as the inner phase shift angle adjustment value.

[0153] 5. If the second switching period is less than the minimum value in the switching period threshold range and the second switching period is greater than 0, the minimum value in the switching period threshold range is determined as the switching period adjustment value, and the ratio of the second switching period to twice the switching period adjustment value is determined as the inner phase shift angle adjustment value.

[0154] 6. According to the switching period adjustment value and the inner phase shift angle adjustment value, the switching period and the switching period of the dual active bridge series resonant converter are adjusted to complete the control of the dual active bridge series resonant converter.

[0155] It can be understood that through the above steps, the internal phase shift angle and switching period of the dual active bridge series resonant converter can be adjusted in real time under light load conditions, avoiding the problem of the internal phase shift angle dropping too fast under high voltage and light load conditions, resulting in increased hard-opening current and increased temperature rise.

[0156] The control method of the dual active bridge series resonant converter in the above embodiment is explained below with reference to a specific embodiment.

[0157] Please refer to Figure 5 For ease of explanation, Figure 5 The entire process is divided into three branches, namely the first branch (for obtaining the first load current reference value i TnetRef ), a second branch (for obtaining an external phase shift angle adjustment value), and a third branch (for obtaining a switching period adjustment value and an internal phase shift angle adjustment value), wherein the first branch includes:

[0158] 1. Get the actual value of the input current I of the first port AC_Rms , and the preset input current limit value I AC_Lim .

[0159] 2. Input current limit value I AC_Lim The actual value of input current I AC_Rms Perform difference calculation to get I ACErr .

[0160] 3. Based on I ACErr A proportional-integral (PI) operation is performed to obtain a first current value.

[0161] 4. Obtain the actual output voltage value U of the second port of the dual active bridge series resonant converter Tnet_Notch And the output voltage command value U TnetCmd .

[0162] 5. Output voltage command value U TnetCmd And the actual value of output voltage U Tnet_Notch Perform difference calculation to get U TnetErr .

[0163] 6. U TnetErr A proportional-integral (PI) operation is performed to obtain a second current value.

[0164] 7. Obtaining the third current value I TnetCmd .

[0165] 8. For the first current value, the second current value, and the third current value I TnetCmd Perform the minimum operation (Min) to obtain the first load current reference value i TnetRef .

[0166] The second branch includes:

[0167] 1. Obtaining the load threshold value I TnetDiff Specifically, voltage-related information is obtained, and the voltage-related information includes: the actual value of the input voltage of the first port, and the actual value of the output voltage of the output port; according to the preset boundary fitting relationship and the voltage-related information, a load boundary value corresponding to the voltage-related information is obtained.

[0168] 2. Obtain the load threshold value I TnetDiff The corresponding outward phase angle

[0169] 3. Pass Get the second load current reference value, sum the first load current reference value and the second load current reference value to get the target load current reference value i TnetRefConv .

[0170] 4. According to the target load current reference value i TnetRefConv and the preset target fitting relationship ( Figure 5 The fitting relationship corresponding to the green curve in the middle) is used to obtain the corresponding external phase angle adjustment value.

[0171] 5. Determine whether the external phase angle adjustment value is within the preset external phase angle threshold range Within (the mathematical expression of this operation is Limit: Limit indicates a limit), if so, it is determined that the external phase angle adjustment value is valid.

[0172] 6. Perform ramp signal processing (Ramp) on the effective value of the external phase angle to obtain the final external phase angle modulation. Based on the external phase angle modulation, the external phase angle of the dual active bridge series resonant converter is adjusted. Make adjustments.

[0173] The third branch includes:

[0174] 1. For the first load current reference value i TnetRef Perform ramp signal processing (Ramp) to obtain the load current modulation amount i TnetRefTmp .

[0175] 2. Load current modulation i TnetRefTmp The actual value of the load current i Tnet Perform difference operation to get I TnetErr .

[0176] 3. According to the difference I TnetErr Perform proportional-integral operation to obtain the first switching period.

[0177] 4. Determine whether the first switching cycle is within the preset threshold range [0, T s_max ] (The mathematical expression of this operation is Limit: [0, T s_max ]), if so, it is determined that the first switching cycle is valid, if not, a new first switching cycle is re-determined.

[0178] 5. When the first switching cycle is determined to be valid, a proportional resonance (PR) operation is performed on the first switching cycle to obtain the second switching cycle T Loopout .

[0179] 6. If the second switching period T Loopout Is it within the preset switching cycle threshold range [T s_min , T s_max ] (The mathematical expression of this operation is If in range:[T s_min , T s_max ]), if so, the second switching period is determined as the switching period adjustment value (T s =T Loopout ). The second switching cycle is subjected to ramp signal processing to obtain a switching cycle modulation amount. Based on the switching cycle modulation amount, the switching cycle T of the dual active bridge series resonant converter is adjusted. s Adjust the internal phase angle preset value, such as 0.5, as the internal phase angle adjustment value.

[0180] 7. If the second switching period is less than the minimum value in the switching period threshold range, and the second switching period is greater than 0 (the mathematical expression of the judgment condition is If in range: [0, T s_min ]), then the minimum value T in the switching cycle threshold range is s_minThe ratio between the second switching period and 2 times the switching period adjustment value is determined as the inner phase angle adjustment value, which is mathematically expressed as: The internal phase shift angle adjustment value is processed by ramp signal to adjust the internal phase shift angle D of the dual active bridge series resonant converter. A Make adjustments.

[0181] The light-load optimization control system of the dual-active bridge series resonant converter provided by the present invention is described below. The light-load optimization control system of the dual-active bridge series resonant converter described below and the light-load optimization control method of the dual-active bridge series resonant converter described above can be referred to each other.

[0182] Please refer to Figure 6 The dual active bridge series resonant converter light load optimization control system provided in this embodiment is applied to a three-port circuit, wherein the three-port circuit includes: a first port, a second port, and a third port. The system includes:

[0183] a target load current reference value determining module 610, configured to obtain a first load current reference value of the second port and an actual output power of the third port, convert the actual output power of the third port into a second load current reference value of the second port, and determine the sum of the first load current reference value and the second load current reference value as a target load current reference value;

[0184] an external phase angle adjustment value acquisition module 620 for obtaining an external phase angle adjustment value corresponding to the target load current reference value based on the target load current reference value and a preset fitting relationship if it is determined that the dual active bridge series resonant converter enters a light load condition;

[0185] The light-load optimization control module 630 is configured to adjust the external phase-shift angle between the full-bridge containing the first port and the full-bridge containing the second port based on the external phase-shift angle adjustment value, and to perform light-load optimization control of the dual-active-bridge series resonant converter by adjusting the internal phase-shift angle of the full-bridge containing the first port and the switching period of the dual-active-bridge series resonant converter. The target load current reference value determination module 610, the external phase-shift angle adjustment value acquisition module 620, and the light-load optimization control module 630 are connected.

[0186] It should be noted that the dual-active bridge series resonant converter light-load optimization control method provided in the above embodiment and the dual-active bridge series resonant converter light-load optimization control system are of the same concept, wherein the specific manner in which each module performs the operation has been described in detail in the method embodiment and will not be repeated here. In actual applications, the dual-active bridge series resonant converter light-load optimization control system provided in the above embodiment can allocate the above functions to different functional modules as needed, that is, divide the internal structure of the system into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0187] Figure 7 For a schematic diagram of the structure of a dual active bridge series resonant converter according to an embodiment of the present invention, please refer to Figure 7 The dual active bridge series resonant converter comprises: a three-port circuit, and the dual active bridge series resonant converter light load optimization control system as described above ( Figure 7 not shown);

[0188] The dual-active-bridge series resonant converter light-load optimization control system controls the drive signals of multiple switching devices in the three-port circuit to adjust the external phase shift angle, internal phase shift angle, and switching period of the dual-active-bridge series resonant converter.

[0189] In some examples of this embodiment, the light-load optimization control system of the dual-active bridge series resonant converter converts the external phase-shift angle adjustment value, the internal phase-shift angle adjustment value, and the switching period adjustment value in the above-mentioned embodiment into a driving signal for each of the above-mentioned switching devices, and uses the driving signal to control each of the switching devices, thereby realizing light-load optimization control of the dual-active bridge series resonant converter.

[0190] The three-port circuit includes: a first port module, a second port module, a third port module, a resonance module, and a transformer module. The first port module includes a voltage source u AC , four power switches (P_Q1, P_Q2, P_Q3, P_Q4), four first power switches (Q1, Q2, Q3, Q4), and an intermediate capacitor C Lnk , voltage source u AC One end is connected to the source of P_Q1 through an inductor, and the other end is connected to the drain of P_Q4. The drain of P_Q1, the drain of P_Q3, the source of P_Q3, the drain of P_Q4, the source of P_Q4, the source of P_Q2, and the source of P_Q1 are connected in sequence to form a loop. The intermediate capacitor C Lnk In parallel with the loop. Q1 and Q2 are connected in series to bridge arm a, and Q3 and Q4 are connected in series to bridge arm b. The resonant module includes a first resonant capacitor C r1 , resonant inductor L r, and the second resonant capacitor C r2 The source of Q1 and the first resonant capacitor C r1 , the primary winding of the transformer module, the resonant inductor L r , and the drain of Q4 are connected in sequence. The second port module includes three bridge arms c, d, and e, each of which is connected in series with two second power switches (such as Q5 to Q10). The second port module also includes an output capacitor C Tnet , output capacitance C Tnet In parallel with the bridge arm e. The source of Q5, the second resonant capacitor C r2 , the first secondary winding of the transformer module is connected to the drain of Q8 in sequence. The drain of Q8 and the second secondary winding of the transformer module are connected to the drain of Q10 in sequence. The third port module includes four third power switches Q11 to Q14, the target inductor Lo, and the output side capacitor C Bnet , a first capacitor C1, and a second capacitor C2. The drain of Q12, the third secondary winding of the transformer module, and the target inductor Lo are connected in sequence. The fourth secondary winding of the transformer module is connected to the drain of Q13 and to the first capacitor C1. The source of Q14 is connected to its drain, and the drain of Q14 is connected to the second capacitor C2. Figure 7 in i AC Indicates the input current sampling point, I Tnet Indicates the load current sampling point of the second port, I Bnet Indicates the load current sampling point of the third port.

[0191] In some embodiments, the output power P of the dual active bridge series resonant converter is o The mathematical expression is:

[0192]

[0193] in, V A Represents the input voltage of the first port, V B represents the output voltage of the second port, f r Represents the resonant frequency, f s represents the switching frequency, Z0 represents the characteristic impedance, which is obtained based on the resonant inductor and resonant capacitor, and π represents pi.

[0194] In some embodiments, an electronic device is also provided. The electronic device may be a server, and its internal structure is shown in FIG. Figure 8As shown. The electronic device includes a processor, a memory, a network interface and a database connected via a system bus. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile and / or 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 network interface of the electronic device is used to communicate with an external client via a network connection. When the computer program is executed by the processor, the functions or steps on the server side of the above method are implemented.

[0195] In some embodiments, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the following steps are implemented: obtaining a first load current reference value of a second port and an actual output power of a third port, converting the actual output power of the third port into a second load current reference value of the second port, and determining the sum of the first load current reference value and the second load current reference value as a target load current reference value; if it is determined that the dual-active bridge series resonant converter enters a light-load operating condition, obtaining an external phase angle adjustment value corresponding to the target load current reference value based on the target load current reference value and a preset fitting relationship; adjusting an external phase angle between the full bridge where the first port is located and the full bridge where the second port is located based on the external phase angle adjustment value, and completing light-load optimization control of the dual-active bridge series resonant converter by adjusting the internal phase angle of the full bridge where the first port is located and the switching period of the dual-active bridge series resonant converter.

[0196] In some embodiments, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented: obtaining a first load current reference value of the second port and an actual output power of the third port, converting the actual output power of the third port into a second load current reference value of the second port, and determining the sum of the first load current reference value and the second load current reference value as a target load current reference value; if it is determined that the dual-active bridge series resonant converter enters a light-load operating condition, obtaining an external phase angle adjustment value corresponding to the target load current reference value based on the target load current reference value and a preset fitting relationship; based on the external phase angle adjustment value, adjusting the external phase angle between the full bridge where the first port is located and the full bridge where the second port is located, and completing the light-load optimization control of the dual-active bridge series resonant converter by adjusting the internal phase angle of the full bridge where the first port is located and the switching period of the dual-active bridge series resonant converter.

[0197] It should be noted that the above functions or steps that can be implemented by the computer-readable storage medium or electronic device can be found in the relevant descriptions of the server side and the client side in the aforementioned method embodiment. To avoid repetition, they will not be described one by one here.

[0198] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the module, program segment, or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0199] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A light-load optimization control method for a dual active bridge series resonant converter, characterized in that: Applied to a three-port circuit, the three-port circuit includes: a first port, a second port, and a third port, the method includes: obtaining a first load current reference value of the second port and an actual output power of the third port, converting the actual output power of the third port into a second load current reference value of the second port, and determining a sum of the first load current reference value and the second load current reference value as a target load current reference value; If it is determined that the dual active bridge series resonant converter enters a light load operating condition, then based on the target load current reference value and a preset fitting relationship, an external phase shift angle adjustment value corresponding to the target load current reference value is obtained; Based on the external phase angle adjustment value, the external phase angle between the full bridge where the first port is located and the full bridge where the second port is located is adjusted, and by adjusting the internal phase angle of the full bridge where the first port is located and the switching period of the dual active bridge series resonant converter, the light load optimization control of the dual active bridge series resonant converter is completed.

2. The light-load optimization control method for a dual active bridge series resonant converter according to claim 1, characterized in that: Converting the actual output power of the third port into a second load current reference value of the second port includes: Obtaining the output voltage and output current of the third port; determining the product of the output voltage and the output current of the third port as the actual output power of the third port; Determine an intermediate power by a ratio between the actual output power of the third port and a preset conversion efficiency, wherein the intermediate power is the power transmitted from the third port to the second port; Obtaining an actual value of the output voltage of the second port; A ratio between the intermediate power and the actual value of the output voltage is determined as the second load current reference value.

3. The light-load optimization control method for a dual active bridge series resonant converter according to claim 1, wherein: Determining that the dual active bridge series resonant converter enters a light load operating condition includes: Acquire voltage-related information, where the voltage-related information includes: an actual value of the input voltage of the first port and an actual value of the output voltage of the second port; Obtaining a load boundary value corresponding to the voltage-related information according to a preset boundary fitting relationship and the voltage-related information, wherein the boundary fitting relationship is a fitting relationship between the voltage-related information and the load boundary value, and the load boundary value is a value of a load current output by the second port when the dual active bridge series resonant converter enters a light-load operating condition; Obtaining an actual value of the load current output by the second port; When the actual value of the load current drops to the load threshold value, it is determined that the dual active bridge series resonant converter enters a light load condition.

4. The light-load optimization control method for a dual active bridge series resonant converter according to claim 3, characterized in that: The acquisition of the boundary fitting relationship includes: Acquiring a plurality of sample point information, the sample point information including: corresponding input voltage sample values, output voltage sample values, and load boundary sample values, the output voltage sample values ​​being sample values ​​of the voltage output by the second port, and the load boundary sample values ​​being sample values ​​of the load current output by the second port when the dual active bridge series resonant converter enters a light load condition; sorting the plurality of sample point information according to the magnitude of the input voltage sample value or the magnitude of the output voltage sample value to obtain a sample point sequence; If the input voltage sample values ​​of a plurality of consecutive sample point information in the sample point sequence are the same, the sample point information with the same input voltage sample value is determined as the first sample point information, and the remaining sample point information is determined as the second sample point information; Fitting is performed on the first sample point information and the second sample point information respectively to obtain the boundary fitting relationship.

5. The light-load optimization control method for a dual active bridge series resonant converter according to claim 3, characterized in that: Fitting the first sample point information and the second sample point information respectively to obtain the boundary fitting relationship includes: Determine the ratio between the output voltage sample value and the input voltage sample value in the first sample point information as a first independent variable, and determine the load boundary sample value in the first sample point information as a first dependent variable; Performing fitting based on the first independent variable and the first dependent variable to obtain a first fitting relationship; obtaining a proportional relationship between input voltage sample values ​​and output voltage sample values ​​in a plurality of second sample point information; determining a ratio between the output voltage sample value and the input voltage sample value in the second sample point information as an intermediate independent variable; and based on the proportional relationship, replacing the input voltage sample value in the intermediate independent variable with an expression containing the corresponding output voltage sample value to obtain a second independent variable; and determining the load boundary sample value in the first sample point information as a second dependent variable; Performing fitting based on the second independent variable and the second dependent variable to obtain a second fitting relationship; The first fitting relationship and the second fitting relationship are determined as the boundary fitting relationship.

6. The light-load optimization control method for a dual active bridge series resonant converter according to claim 1, characterized in that: Determining the preset fitting relationship includes: Acquire a plurality of information to be fitted, wherein the information to be fitted includes mutually corresponding load current sample values ​​and external phase shift angle sample values; A cubic polynomial fitting is performed on the information to be fitted to obtain the preset fitting relationship, where the independent variable in the preset fitting relationship is the load current sample value, and the dependent variable in the preset fitting relationship is the external shift phase angle sample value.

7. The light-load optimization control method for a dual active bridge series resonant converter according to claim 1, characterized in that: The obtaining of the first load current reference value includes: Obtaining an actual input current value of the first port and a preset input current limit value; Performing a proportional-integral operation based on a difference between the actual input current value and the input current limit value to obtain a first current value; Acquire an actual output voltage value and an output voltage command value of the second port, where the output voltage command value refers to the output voltage value of the second port in the control instruction received by the dual active bridge series resonant converter; Performing a proportional-integral operation based on a difference between the actual output voltage value and the output voltage command value to obtain a second current value; Obtaining a third current value, where the third current value refers to an output current value of the second port in the control instruction; A minimum value among the first current value, the second current value, and the third current value is determined as the first load current reference value.

8. The light-load optimization control method for a dual active bridge series resonant converter according to claim 1, characterized in that: The light-load optimization control of the dual-active-bridge series resonant converter is completed by adjusting the internal phase shift angle of the full bridge where the first port is located and the switching period of the dual-active-bridge series resonant converter, including: Obtaining an actual value of the load current of the second port; Performing a proportional-integral operation based on a difference between the first load current reference value and the actual load current value to obtain a first switching period; performing a proportional resonance operation according to the first switching period to obtain a second switching period; If the second switching period is within a preset switching period threshold range, the second switching period is determined as the switching period adjustment value, and the preset inner phase shift angle value is determined as the inner phase shift angle adjustment value; If the second switching period is less than a minimum value in the switching period threshold range and the second switching period is greater than 0, the minimum value in the switching period threshold range is determined as the switching period adjustment value, and a ratio between the second switching period and twice the switching period adjustment value is determined as the inner phase shift angle adjustment value; According to the switching period adjustment value and the inner phase shift angle adjustment value, the switching period and the switching period of the dual active bridge series resonant converter are adjusted to complete the control of the dual active bridge series resonant converter.

9. A light-load optimization control system for a dual active bridge series resonant converter, characterized in that: Applied to a three-port circuit, the three-port circuit includes: a first port, a second port, and a third port, the system includes: a target load current reference value determining module, configured to obtain a first load current reference value of the second port and an actual output power of the third port, convert the actual output power of the third port into a second load current reference value of the second port, and determine the sum of the first load current reference value and the second load current reference value as a target load current reference value; an external phase angle adjustment value acquisition module, configured to obtain an external phase angle adjustment value corresponding to the target load current reference value based on the target load current reference value and a preset fitting relationship if it is determined that the dual active bridge series resonant converter enters a light load condition; A light-load optimization control module is configured to adjust the external phase-shift angle between the full bridge where the first port is located and the full bridge where the second port is located based on the external phase-shift angle adjustment value, and to complete light-load optimization control of the dual-active-bridge series resonant converter by adjusting the internal phase-shift angle of the full bridge where the first port is located and the switching period of the dual-active-bridge series resonant converter.

10. A dual active bridge series resonant converter, characterized in that: It includes a three-port circuit and a light-load optimization control system for a dual active bridge series resonant converter as claimed in claim 9; The dual-active-bridge series resonant converter light-load optimization control system controls the drive signals of multiple switching devices in the three-port circuit to adjust the external phase shift angle, internal phase shift angle, and switching period of the dual-active-bridge series resonant converter.

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