Dual active bridge conversion circuit and voltage and current equalization control method

Abstract

The present application proposes a dual active bridge conversion circuit and a voltage and current equalization control method. Through the method of the embodiment of the present application: the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module are switched to different connection relationships; the first output value of the first dual active bridge conversion module and the second output value of the second dual active bridge conversion module corresponding to the connection relationship are collected; when the difference between the first output value and the second output value is greater than the preset difference, the first target phase shift angle is determined according to the first output value and the output given value; and the second target phase shift angle is determined according to the second output value and the output given value; a first signal is generated according to the first target phase shift angle, and a second signal is generated according to the second target phase shift angle; a first signal is sent to the first dual active bridge conversion module, and a second signal is sent to the second dual active bridge conversion module. The present application can improve the efficiency of voltage and current equalization of the dual active bridge conversion circuit and enhance the stability of the circuit.

Description

Technical Field

[0001] The present application relates to the technical field of power electronic converters, and in particular to a dual active bridge conversion circuit and a voltage and current equalization control method. Background Art

[0002] As an isolated bidirectional DC / DC converter topology solution, dual active bridge has been widely used due to its wide voltage regulation range and high efficiency. With high power and wider voltage regulation range, it has gradually become an industry development trend. Based on the ability of dual active bridge topology to transmit power, as well as the large peak and effective value of the converter's inductor current, it is suitable for series and parallel combination of multiple converters to achieve power improvement and widen the voltage range. However, when connecting in series or parallel, it is necessary to consider how to deal with the problem of series voltage balancing and parallel current balancing.

[0003] The existing dual active bridge converter voltage and current balancing solutions usually require two controllers and their peripheral circuits. The entire loop control is relatively complex, the voltage and current balancing effects are poor, and resources are relatively wasted. In addition, when one controller is used for two independent loop controls, the effective duty cycle of the primary bridge arm HB1 is usually adjusted. The effective duty cycle of the secondary bridge arm HB2 The phase shift angle between the midpoints When the input ends of the first dual active bridge conversion circuit and the second dual active bridge circuit are connected in parallel and the output ends are switched in series and parallel, the voltage and current are balanced by adjusting , get new Acting on the waves, As the loop calculation result, it is also necessary to obtain the external shift phase angle of the primary bridge arm and the secondary bridge arm through calculation conversion. , the internal phase angle of the primary bridge arm and the internal phase angle of the secondary bridge arm The three control parameters act on the switch tube, which means there will be two different sets of , , acting on each switch tube. The calculation method is relatively complicated, and many variables are changed. The outer phase angle and inner phase angle of the first and second dual active bridge conversion circuits are changed, and the effect and efficiency of voltage and current balancing are low, which reduces the stability of the entire circuit. Summary of the invention

[0004] The present application provides a dual active bridge conversion circuit and a voltage and current equalization control method, which collects output voltage values ​​when the output ends of the dual active bridge conversion circuits are connected in series, thereby determining whether there is uneven voltage, and adjusting the external phase shift angle or internal phase shift angle of the primary bridge arm and the secondary bridge arm of the dual active bridge conversion circuit according to the output voltage value and the output voltage set value, and collects output current values ​​when the output ends of the dual active bridge conversion circuits are connected in parallel, thereby determining whether there is uneven current, and adjusting the external phase shift angle or internal phase shift angle of the primary bridge arm and the secondary bridge arm of the dual active bridge conversion circuit according to the output current value and the output current set value, so as to achieve voltage and current equalization at the output end of the dual active bridge conversion circuit, and can directly adjust one of the external phase shift angle and the internal phase shift angle of the primary bridge arm and the secondary bridge arm without changing other phase shift angles, which is beneficial to improving the efficiency of voltage and current equalization control, reducing complexity, and improving circuit stability.

[0005] In a first aspect, an embodiment of the present application provides a dual active bridge conversion circuit, the dual active bridge conversion circuit comprising a power supply module, a first dual active bridge conversion module, a second dual active bridge conversion module, a series-parallel switching module, a sampling module, a detection module, and a control module, wherein the input sides of the first dual active bridge conversion module and the second dual active bridge conversion module are connected in parallel to the power supply module, wherein:

[0006] The series-parallel switching module is used to switch the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module to different connection relationships, wherein the connection relationship includes a series relationship and a parallel relationship;

[0007] The sampling module is used to collect, according to the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module, a first output value of the first dual active bridge conversion module corresponding to the connection relationship, and collect a second output value of the second dual active bridge conversion module corresponding to the connection relationship, wherein the output value is an output voltage value or an output current value;

[0008] The detection module is used to detect whether the difference between the first output value and the second output value is greater than a preset difference, and the preset difference is a preset voltage difference or a preset current difference;

[0009] The control module is used to determine a first target phase shift angle according to the first output value and an output given value when the difference is greater than the preset difference, the output given value being an output voltage given value or an output current given value, the first target phase shift angle being a target adjustment value corresponding to an inner phase shift angle of a primary bridge arm or an inner phase shift angle of a secondary bridge arm or an outer phase shift angle between the primary bridge arm and the secondary bridge arm of the first dual active bridge conversion module; and, determine a second target phase shift angle according to the second output value and the output given value, the second target phase shift angle being a target adjustment value corresponding to an inner phase shift angle of a primary bridge arm or an inner phase shift angle of a secondary bridge arm or an outer phase shift angle between the primary bridge arm and the secondary bridge arm of the second dual active bridge conversion module; and, generate a first signal according to the first target phase shift angle, and generate a second signal according to the second target phase shift angle; and, send the first signal to the first dual active bridge conversion module, and send the second signal to the second dual active bridge conversion module.

[0010] In a possible implementation, the sampling module includes a voltage sampling module and a current sampling module, the first dual active bridge conversion module includes a first input module and a first output module, and the second dual active bridge conversion module includes a second input module and a second output module; the sampling module is connected to the first output module and the second output module respectively, wherein,

[0011] The first input module includes a first primary bridge arm, the first output module includes a first secondary bridge arm, a first current sampling resistor and a first output bus capacitor, the first end of the first secondary bridge arm is connected to the second end of the first current sampling resistor, the second end of the first secondary bridge arm is connected to the first end of the first output bus capacitor, the first end of the first current sampling resistor is connected to the second end of the first output bus capacitor, and the first end of the first output bus capacitor is connected to the first end of the voltage sampling module;

[0012] The second input module includes a second primary bridge arm, the first output module includes a second secondary bridge arm, a second current sampling resistor and a second output bus capacitor, the first end of the second secondary bridge arm is connected to the second end of the second current sampling resistor, the second end of the second secondary bridge arm is connected to the first end of the second output bus capacitor, the first end of the second current sampling resistor is connected to the second end of the second output bus capacitor, the first end of the second output bus capacitor is connected to the second end of the voltage sampling module, and the current sampling module is respectively connected to both ends of the first current sampling resistor and the second current sampling resistor.

[0013] In a possible implementation, the dual active bridge conversion circuit further includes a comparison module, wherein:

[0014] The comparison module is used to obtain the target output voltage value of the first dual active bridge conversion module and the second dual active bridge conversion module; and, compare the target output voltage value with a preset threshold value to obtain a comparison result; and, according to the comparison result, send a series signal or a parallel signal to the series-parallel switching module.

[0015] In a possible implementation, when the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, the voltage sampling module is used to collect the first output voltage value of the first dual active bridge conversion module and the second output voltage value of the second dual active bridge conversion module;

[0016] When the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship, the current sampling module is used to collect the first output current value of the first dual active bridge conversion module and the second output current value of the second dual active bridge conversion module;

[0017] The detection module is used to detect whether the difference between the first output voltage value and the second output voltage value is greater than the preset voltage difference in the series relationship; and is used to detect whether the difference between the first output current value and the second output current value is greater than the preset current difference in the parallel relationship;

[0018] The control module is used to determine the first target phase shift angle according to the first output voltage value and the output voltage given value when the difference value is greater than the preset voltage difference value under the series relationship; and determine the second target phase shift angle according to the second output voltage value and the output voltage given value; and generate a first signal according to the first target phase shift angle, and generate a second signal according to the second target phase shift angle; and send the first signal to the first dual active bridge conversion module, and send the second signal to the second dual active bridge conversion module;

[0019] The control module is also used to, under the parallel relationship, determine the first target phase shift angle according to the first output current value and the output current given value when the difference is greater than the preset current difference; and determine the second target phase shift angle according to the second output current value and the output current given value; and generate the first signal according to the first target phase shift angle, and generate the second signal according to the second target phase shift angle; and send the first signal to the first dual active bridge conversion module, and send the second signal to the second dual active bridge conversion module.

[0020] In a possible implementation, the series-parallel switching module includes a first switch, a second switch, a third switch and a fourth switch; the first end of the first switch is connected to the second end of the first secondary bridge arm, the second end of the first switch is connected to the second end of the second secondary bridge arm, the first end of the second switch is connected to the first end of the first secondary bridge arm, the second end of the second switch is connected to the first end of the second secondary bridge arm, the first end of the third switch is connected to the first end of the first current sampling resistor, the second end of the third switch is connected to the second end of the first output bus capacitor, the first end of the fourth switch is connected to the second end of the second secondary bridge arm, and the second end of the fourth switch is connected to the first end of the second output bus capacitor, wherein,

[0021] In response to the series signal of the comparison module, the series-parallel switching module controls the first switch and the second switch to be disconnected and the third switch and the fourth switch to be closed, so that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, and,

[0022] In response to the parallel signal of the comparison module, the series-parallel switching module controls the first switch and the second switch to be closed and the third switch and the fourth switch to be opened, so that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship.

[0023] In a possible implementation, the switch tube of the first dual active bridge conversion module includes a first primary switch tube and a first secondary switch tube, and the switch tube of the second dual active bridge conversion module includes a second primary switch tube and a second secondary switch tube, wherein:

[0024] The first primary switch tube is located in the first primary bridge arm, and the first primary switch tube includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, the first switch tube and the second switch tube are connected in series, the third switch tube and the fourth switch tube are connected in series, and the first switch tube, the second switch tube and the third switch tube and the fourth switch tube are connected in parallel;

[0025] The first secondary switch tube is located in the first secondary bridge arm, and the first secondary switch tube includes a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube, the fifth switch tube and the sixth switch tube are connected in series, the seventh switch tube and the eighth switch tube are connected in series, and the fifth switch tube, the sixth switch tube, the seventh switch tube and the eighth switch tube are connected in parallel;

[0026] The second primary switch tube is located in the second primary bridge arm, and the second primary switch tube includes an eleventh switch tube, a twelfth switch tube, a thirteenth switch tube and a fourteenth switch tube, the eleventh switch tube and the twelfth switch tube are connected in series, the thirteenth switch tube and the fourteenth switch tube are connected in series, and the eleventh switch tube, the twelfth switch tube and the thirteenth switch tube and the fourteenth switch tube are connected in parallel;

[0027] The second secondary side switch tube is located at the second secondary side bridge arm, and the second secondary side switch tube includes a fifteenth switch tube, a sixteenth switch tube, a seventeenth switch tube and an eighteenth switch tube, the fifteenth switch tube and the sixteenth switch tube are connected in series, the seventeenth switch tube and the eighteenth switch tube are connected in series, and the fifteenth switch tube, the sixteenth switch tube and the seventeenth switch tube and the eighteenth switch tube are connected in parallel.

[0028] In a second aspect, an embodiment of the present application provides a voltage and current balancing control method, which is applied to the circuit as described in the first aspect, and the method includes:

[0029] In response to the series signal or the parallel signal of the comparison module, the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module are switched to different connection relationships through the series-parallel switching module, and the connection relationship includes a series relationship and a parallel relationship;

[0030] According to the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module, a first output value of the first dual active bridge conversion module corresponding to the connection relationship is collected, and a second output value of the second dual active bridge conversion module corresponding to the connection relationship is collected, and the output value is an output voltage value or an output current value;

[0031] Detecting whether a difference between the first output value and the second output value is greater than a preset difference, where the preset difference is a preset voltage difference or a preset current difference;

[0032] When the difference is greater than the preset difference, a first target phase shift angle is determined according to the first output value and the output given value, the output given value being an output voltage given value or an output current given value, and the first target phase shift angle is a target adjustment value corresponding to an inner phase shift angle of the primary bridge arm of the first dual-active bridge conversion module or an inner phase shift angle of the secondary bridge arm or an outer phase shift angle between the primary bridge arm and the secondary bridge arm; and a second target phase shift angle is determined according to the second output value and the output given value, the second target phase shift angle is a target adjustment value corresponding to an inner phase shift angle of the primary bridge arm of the second dual-active bridge conversion module or an inner phase shift angle of the secondary bridge arm or an outer phase shift angle between the primary bridge arm and the secondary bridge arm;

[0033] generating a first signal according to the first target phase shift angle, and generating a second signal according to the second target phase shift angle;

[0034] The first signal is sent to the first dual active bridge conversion module, and the second signal is sent to the second dual active bridge conversion module.

[0035] It can be seen that in the embodiment of the present application, by implementing the embodiment of the present application, when the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module are connected in series, the output voltage values ​​of the first and second dual active bridge conversion modules are respectively collected to determine whether there is uneven voltage, and then the target phase shift angles of the first and second dual active bridge conversion modules are respectively determined according to the output voltage value and the given voltage value, and then the voltage is equalized in the series case by adjusting to the target phase shift angle, and when the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module are connected in parallel, the output current values ​​of the first and second dual active bridge conversion modules are respectively collected to determine whether there is uneven current, and then the target phase shift angles of the first and second dual active bridge conversion modules are respectively determined according to the output current value and the given current value, and then the current is equalized in the parallel case by adjusting to the target phase shift angle. In this way, compared with the existing scheme of achieving voltage and current equalization by adjusting the phase shift angle between the midpoints of the duty cycles of the primary bridge arm and the secondary bridge arm, there is no need to determine different external phase shift angles and internal phase shift angles for the first and second dual active bridge conversion modules according to the phase shift angle between the midpoints of the duty cycles. Instead, voltage and current equalization can be achieved by directly changing one of the external phase shift angle and the internal phase shift angle, which is beneficial to improving the efficiency of voltage and current equalization and improving the stability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 is a circuit diagram of a dual active bridge conversion circuit provided in an embodiment of the present application;

[0038] Figure 2 It is a schematic diagram of the composition of a dual active bridge conversion circuit provided in an embodiment of the present application;

[0039] Figure 3 It is a schematic diagram of the phase shift angle relationship of a dual active bridge conversion circuit provided in an embodiment of the present application;

[0040] Figure 4 It is a schematic diagram of the relationship between transmission power and phase shift angle provided in an embodiment of the present application;

[0041] Figure 5a It is an inductor current timing diagram for adjusting the external phase shift angle of a dual active bridge conversion circuit provided by an embodiment of the present application;

[0042] Figure 5b It is an inductor current timing diagram for adjusting the internal phase shift angle of the primary bridge arm provided in an embodiment of the present application;

[0043] Figure 5c It is an inductor current timing diagram for adjusting the internal phase shift angle of the secondary bridge arm provided in an embodiment of the present application;

[0044] Figure 6 This is a diagram of a pressure equalizing ring control architecture provided in an embodiment of the present application;

[0045] Figure 7 This is a current sharing loop control architecture diagram provided in an embodiment of the present application;

[0046] Figure 8 It is a flow chart of a voltage and current equalization control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0049] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0050] In the embodiments of the present application, "and / or" describes the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists alone; A and B exist at the same time; B exists alone. Among them, A and B can be singular or plural.

[0051] In the embodiment of the present application, the symbol " / " can indicate that the objects associated with each other are in an "or" relationship. In addition, the symbol " / " can also indicate a division sign, that is, performing a division operation. For example, A / B can indicate A divided by B.

[0052] In the embodiments of the present application, "equal to" can be used in conjunction with greater than, and is applicable to the technical solution adopted when greater than, and can also be used in conjunction with less than, and is applicable to the technical solution adopted when less than. When equal to is used in conjunction with greater than, it is not used in conjunction with less than; when equal to is used in conjunction with less than, it is not used in conjunction with greater than.

[0053] At present, the existing dual active bridge converter voltage and current balancing solutions usually adjust the effective duty cycle of the primary bridge arm HB1 when using one controller to perform two independent loop controls. The effective duty cycle of the secondary bridge arm HB2 The phase shift angle between the midpoints To perform voltage and current equalization control, it is necessary to calculate and convert the external phase angle between the primary bridge arm and the secondary bridge arm. , the internal phase angle of the primary bridge arm and the internal phase angle of the secondary bridge arm , the outer phase angle and the inner phase angle of the first and second dual active bridge conversion circuits are changed, the voltage and current equalization effect and efficiency are low, and the stability of the entire circuit is reduced.

[0054] In view of the above problems, an embodiment of the present application provides a dual active bridge conversion circuit and a voltage and current equalization control method. The embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0055] See also Figure 1 , Figure 1 is a circuit diagram of a dual active bridge conversion circuit provided in an embodiment of the present application. Figure 1 As shown, the dual active bridge conversion circuit includes a first dual active bridge conversion circuit and a second dual active bridge conversion circuit.

[0056] In a possible embodiment, the input side of the first dual active bridge conversion circuit includes a first primary bridge arm HB1, and the output side includes a first secondary bridge arm HB2, a first current sampling resistor Isamp1, and a first output bus capacitor C1. The first end of the first secondary bridge arm HB2 is connected to the second end of the first current sampling resistor Isamp1, the second end of the first secondary bridge arm HB2 is connected to the first end of the first output bus capacitor C1, the first end of the first current sampling resistor Isamp1 is connected to the second end of the first output bus capacitor C1, the first end of the first output bus capacitor C1 is connected to the first end of the voltage sampling module, and the first output bus voltage Vo1 can be obtained at the first end of the first output bus capacitor C1;

[0057] The input side of the second dual active bridge conversion circuit includes a second primary bridge arm HB3, the first output module includes a second secondary bridge arm HB4, a second current sampling resistor Isamp2 and a second output bus capacitor C2, the first primary bridge arm HB1 and the second primary bridge arm HB3 are connected in parallel to the two ends of the input bus capacitor Cbus, one end of the input bus capacitor Cbus is connected to the input DC bus side voltage Vin, the first secondary bridge arm HB2 and the second secondary bridge arm HB4 are connected to the filter after series-parallel switching, and soft start can be performed to rectify the positive terminal voltage Vo+ on the battery side and the negative terminal voltage Vo- on the battery side, the first end of the second secondary bridge arm HB4 is connected to the second end of the second current sampling resistor Isamp2, the second end of the second secondary bridge arm HB4 is connected to the first end of the second output bus capacitor C2, the second output bus voltage Vo2 can be obtained at the first end of the second output bus capacitor C2, the first end of the second current sampling resistor Isamp2 is connected to the second end of the second output bus capacitor C2, and the first end of the second output bus capacitor C2 is connected to the second end of the voltage sampling module.

[0058] In a possible embodiment, a first main transformer Tr1 is included between the first primary bridge arm HB1 and the first secondary bridge arm HB2. The first primary bridge arm HB1 is connected to both ends of the input bus capacitor Cbus, and the first primary bridge arm HB1 includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4. The first switch tube Q1 and the second switch tube Q2 are connected in series and connected to both ends of the first primary bridge arm HB1. The third switch tube Q3 and the fourth switch tube Q4 are connected in series and connected to both ends of the first primary bridge arm HB1. The first switch tube Q1, the second switch tube Q2 and the third switch tube Q3 and the fourth switch tube Q4 are connected in parallel. A point A between the first switch tube Q1 and the second switch tube Q2 is connected to the first end of the first resonant inductor L1, and the second end of the first resonant inductor L1 is connected to the first end of the first primary DC blocking capacitor Cd1. The first end of the first primary DC blocking capacitor Cd1 is connected to the first end of the first primary DC blocking capacitor Cd1. The two ends are connected to the point B between the third switch tube Q3 and the fourth switch tube Q4; and the first secondary bridge arm HB2 includes a fifth switch tube Q5, a sixth switch tube Q6, a seventh switch tube Q7 and an eighth switch tube Q8, the fifth switch tube Q5 and the sixth switch tube Q6 are connected in series and connected to the two ends of the first secondary bridge arm HB2, the seventh switch tube Q7 and the eighth switch tube Q8 are connected in series and connected to the two ends of the first secondary bridge arm HB2, the fifth switch tube Q5, the sixth switch tube Q6 and the seventh switch tube Q7, the eighth switch tube Q8 are connected in parallel, the point C between the fifth switch tube Q5 and the sixth switch tube Q6 is connected to the first end of the first secondary DC blocking capacitor Cd3, and the second end of the first secondary DC blocking capacitor Cd3 is connected to the point D between the seventh switch tube Q7 and the eighth switch tube Q8;

[0059] A second main transformer Tr2 is included between the second primary bridge arm HB3 and the second secondary bridge arm HB4. The second primary bridge arm HB3 is connected to both ends of the input bus capacitor Cbus, and the second primary bridge arm HB3 includes an eleventh switch tube Q11, a twelfth switch tube Q12, a thirteenth switch tube Q13 and a fourteenth switch tube Q14. The eleventh switch tube Q11 and the twelfth switch tube Q12 are connected in series and then connected to both ends of the second primary bridge arm HB3. The thirteenth switch tube Q13 and the fourteenth switch tube Q14 are connected in series and then connected to both ends of the second primary bridge arm HB3. The eleventh switch tube Q11, the twelfth switch tube Q12 and the thirteenth switch tube Q13, the fourteenth switch tube Q14 are connected in parallel. The point E between the eleventh switch tube Q11 and the twelfth switch tube Q12 is connected to the eleventh end of the second resonant inductor L2, the twelfth end of the second resonant inductor L2 is connected to the eleventh end of the second primary DC blocking capacitor Cd2, and the twelfth end of the second primary DC blocking capacitor Cd2 is connected to the The first and second secondary bridge arms HB4 are connected to the point F between the thirteenth switch tube Q13 and the fourteenth switch tube Q14; and the second secondary bridge arm HB4 includes the fifteenth switch tube Q15, the sixteenth switch tube Q16, the seventeenth switch tube Q17 and the eighteenth switch tube Q18, the fifteenth switch tube Q15 and the sixteenth switch tube Q16 are connected in series and connected to the two ends of the second secondary bridge arm HB4, the seventeenth switch tube Q17 and the eighteenth switch tube Q18 are connected in series and connected to the two ends of the second secondary bridge arm HB4, the fifteenth switch tube Q15 and the sixteenth switch tube Q16 and the seventeenth switch tube Q17 and the eighteenth switch tube Q18 are connected in parallel, the point G between the fifteenth switch tube Q15 and the sixteenth switch tube Q16 is connected to the eleventh end of the second secondary DC blocking capacitor Cd4, and the twelfth end of the second secondary DC blocking capacitor Cd4 is connected to the point H between the seventeenth switch tube Q17 and the eighteenth switch tube Q18.

[0060] Among them, the dual active bridge conversion circuit also includes a first switch K1, a second switch K2, a third switch K3 and a fourth switch K4; the first end of the first switch K1 is connected to the second end of the first secondary bridge arm HB2, the second end of the first switch K1 is connected to the second end of the second secondary bridge arm HB4, the first end of the second switch K2 is connected to the first end of the first secondary bridge arm HB2, the second end of the second switch K2 is connected to the first end of the second secondary bridge arm HB4, the first end of the third switch K3 is connected to the first end of the first current sampling resistor Isamp1, the second end of the third switch K3 is connected to the second end of the first output bus capacitor C1, the first end of the fourth switch K4 is connected to the second end of the second secondary bridge arm HB4, and the second end of the fourth switch K4 is connected to the first end of the second output bus capacitor C2.

[0061] See also Figure 2 , Figure 2 Schematic diagram of the composition of a dual active bridge conversion circuit provided in an embodiment of the present application. Figure 2As shown, the dual active bridge conversion circuit includes a power supply module, a first dual active bridge conversion module, a second dual active bridge conversion module, a series-parallel switching module, a sampling module, a detection module, a comparison module and a control module.

[0062] Among them, the first dual active bridge conversion module and the second dual active bridge conversion module are connected in parallel to the power supply module, the first dual active bridge conversion module and the second dual active bridge conversion module are respectively connected to the series-parallel switching module and the sampling module, and the control module is respectively connected to the series-parallel switching module, the sampling module, the detection module and the comparison module.

[0063] In a possible embodiment, the series-parallel switching module is used to switch the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module to different connection relationships, wherein the connection relationship includes a series relationship and a parallel relationship;

[0064] The sampling module is used to collect, according to the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module, a first output value of the first dual active bridge conversion module corresponding to the connection relationship, and collect a second output value of the second dual active bridge conversion module corresponding to the connection relationship, wherein the output value is an output voltage value or an output current value;

[0065] The detection module is used to detect whether the difference between the first output value and the second output value is greater than a preset difference, and the preset difference is a preset voltage difference or a preset current difference;

[0066] The control module is used to determine a first target phase shift angle according to the first output value and an output given value when the difference is greater than the preset difference, the output given value being an output voltage given value or an output current given value, the first target phase shift angle being a target adjustment value corresponding to an inner phase shift angle of a primary bridge arm or an inner phase shift angle of a secondary bridge arm or an outer phase shift angle between the primary bridge arm and the secondary bridge arm of the first dual active bridge conversion module; and, determine a second target phase shift angle according to the second output value and the output given value, the second target phase shift angle being a target adjustment value corresponding to an inner phase shift angle of a primary bridge arm or an inner phase shift angle of a secondary bridge arm or an outer phase shift angle between the primary bridge arm and the secondary bridge arm of the second dual active bridge conversion module; and, generate a first signal according to the first target phase shift angle, and generate a second signal according to the second target phase shift angle; and, send the first signal to the first dual active bridge conversion module, and send the second signal to the second dual active bridge conversion module.

[0067] Wherein, the sampling module includes a voltage sampling module and a current sampling module.

[0068] In a possible embodiment, when the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, the voltage sampling module is used to collect the first output voltage value of the first dual active bridge conversion module and the second output voltage value of the second dual active bridge conversion module;

[0069] When the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship, the current sampling module is used to collect the first output current value of the first dual active bridge conversion module and the second output current value of the second dual active bridge conversion module;

[0070] The detection module is used to detect whether the difference between the first output voltage value and the second output voltage value is greater than the preset voltage difference in the series relationship; and is used to detect whether the difference between the first output current value and the second output current value is greater than the preset current difference in the parallel relationship;

[0071] The control module is used to determine the first target phase shift angle according to the first output voltage value and the output voltage given value when the difference value is greater than the preset voltage difference value under the series relationship; and determine the second target phase shift angle according to the second output voltage value and the output voltage given value; and generate a first signal according to the first target phase shift angle, and generate a second signal according to the second target phase shift angle; and send the first signal to the first dual active bridge conversion module, and send the second signal to the second dual active bridge conversion module;

[0072] The control module is also used to, under the parallel relationship, determine the first target phase shift angle according to the first output current value and the output current given value when the difference is greater than the preset current difference; and determine the second target phase shift angle according to the second output current value and the output current given value; and generate the first signal according to the first target phase shift angle, and generate the second signal according to the second target phase shift angle; and send the first signal to the first dual active bridge conversion module, and send the second signal to the second dual active bridge conversion module.

[0073] In a possible embodiment, the comparison module is used to obtain the target output voltage value of the first dual active bridge conversion module and the second dual active bridge conversion module; and, compare the target output voltage value with a preset threshold value to obtain a comparison result; and, according to the comparison result, send a series signal or a parallel signal to the series-parallel switching module.

[0074] In a possible embodiment, the series-parallel switching module is used to respond to the series signal of the comparison module, and the series-parallel switching module controls the first switch and the second switch to be disconnected and the third switch and the fourth switch to be closed, so that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, and,

[0075] In response to the parallel signal of the comparison module, the series-parallel switching module controls the first switch and the second switch to be closed and the third switch and the fourth switch to be opened, so that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship.

[0076] It can be seen that in this embodiment, the control module switches the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module to a series relationship or a parallel relationship through the comparison result of the comparison module. When it is a series relationship, the output voltages of the first dual active bridge conversion module and the second dual active bridge conversion module are respectively obtained through the voltage sampling module, and the target phase shift angle is determined according to the output voltage and the given voltage value; and, when it is a parallel relationship, the output currents of the first dual active bridge conversion module and the second dual active bridge conversion module are respectively obtained through the current sampling module, and the target phase shift angle is determined according to the output current and the given current value, so as to achieve voltage balancing when the output end of the dual active bridge conversion circuit is connected in series and current balancing when connected in parallel according to the target phase shift angle, which is beneficial to improving the efficiency of voltage and current balancing and improving circuit stability.

[0077] See also Figure 3 , Figure 3 Schematic diagram of the phase shift angle relationship of a dual active bridge conversion circuit provided in an embodiment of the present application. Figure 3 As shown, the phase shift angle includes the external phase shift angle of the first primary bridge arm HB1 and the first secondary bridge arm HB2 in the first dual active bridge conversion circuit. , the internal phase angle of the first primary bridge arm HB1 、The internal phase shift angle of the first secondary bridge arm HB2 , the duty cycle of the first primary bridge arm HB1 in half a cycle The duty cycle of the first secondary bridge arm HB2 in half a cycle The phase shift angle between the midpoints .

[0078] Among them, Vin is the input DC bus side voltage, NVo1 is the voltage output by the first secondary bridge arm equivalent to the voltage of the first primary bridge arm, so the voltage transformation ratio k=NVo1 / Vin can be defined. is the external phase shift angle of HB1 and HB2, that is, the phase shift angle of the first switch tube Q1 in HB1 is ahead of the fifth switch tube Q5 in HB2; is the internal phase shift angle of the HB1 bridge, that is, the internal phase shift angle of the first switch tube Q1 in HB1 is ahead of the fourth switch tube Q4; is the internal phase shift angle of the HB2 bridge, that is, the internal phase shift angle of the fifth switch tube Q5 in HB2 is ahead of the eighth switch tube Q8. A square wave voltage is obtained on the HB1 side and the HB2 side respectively. and , The voltage from HB2 to HB1 is equivalent. Since the transformer ratio is set to N, the voltage value changes by N. The energy between the two voltage sources is transmitted through the auxiliary inductor L1 and the leakage inductance of the transformer, which is equivalent to L.

[0079] in, For HB1 side The effective duty cycle within half a cycle, For HB2 side The effective duty cycle in half a cycle, so , Always greater than or equal to 0 and less than or equal to 1. for Lagging behind The phase shift angle is and the phase shift angle between the midpoints; and, express 0 to The rising edge lags behind 0 to The phase shift of the rising edge, Mainly used for mathematical calculations.

[0080] Among them, in the time axis, when time t is 0, the first primary bridge arm HB1 has passed the inner phase shift angle After starting at half the duty cycle Generating voltage ; The first secondary bridge arm HB2 has passed the external phase angle and internal phase angle After that, in half duty cycle Internally generated voltage N .

[0081] Specifically, , , and , , The conversion relationship between them is:

[0082] = + (1)

[0083] =1- (2)

[0084] =1- (3)

[0085] Among them, -1< <=1,0<= , <=1.

[0086] It can be seen that in this embodiment, according to , , and , , The conversion relationship between them is known. As the loop calculation result, it is also necessary to obtain , , The three control parameters act on the switch tube. In the embodiment of the present application, the , and One of them is used to achieve voltage and current balancing. Compared with the existing normal voltage and current balancing loop strategies, both act on the loop calculation results. Get new Acting on the wave, it means there will be two different sets of , , acting on each switching tube, can reduce the amount of calculation, improve the efficiency of voltage and current balancing, and improve circuit stability.

[0087] See also Figure 4 , Figure 4 Schematic diagram of the relationship between transmission power and phase shift angle provided in an embodiment of the present application. Figure 4 As shown, the relationship diagram is a three-dimensional statistical diagram, and the three coordinate axes of the three-dimensional statistical diagram respectively represent the output power Pstar, the coefficient K, and the duty cycle of the first primary bridge arm HB1 in half a cycle. The duty cycle of the first secondary bridge arm HB2 in half a cycle The phase shift angle between the midpoints .

[0088] Among them, in the single phase shift modulation mode, when =1, When the transmission power value Pstar and The expression is as follows:

[0089] Pstar=4K (1- )(4)

[0090] Among them, in the three-dimensional statistical chart, when 0<= <=0.5, the transmission power Pstar increases with monotonically increasing; and, =0.5, =1 and When , the transmission power Pstar is maximum.

[0091] It can be understood that according to formula (1), =1, In the case of and There is a positive correlation between them, and according to formula (4) and the three-dimensional statistical graph, it can be seen that when 0<= <=0.5, the transmission power Pstar Monotonically increasing, so we can know that when 0<= <=0.5, the output power Pstar is also monotonically increasing. Therefore, by changing , the transmission power Pstar can be changed, that is, The output power of the first dual active bridge conversion circuit and the second dual active bridge conversion circuit is adjusted, that is, the output voltage or the output current is changed, so as to achieve voltage and current balancing.

[0092] It can be seen that in this embodiment, the inherent principle of achieving voltage and current balancing by adjusting the external phase angle of the dual active bridge conversion circuit is given, which illustrates that there is no need to adjust the duty cycle of the first primary bridge arm HB1 in half a cycle. The duty cycle of the first secondary bridge arm HB2 in half a cycle The phase shift angle between the midpoints To achieve equal pressure and current, the external phase angle can be directly adjusted in the embodiment of the present application. In order to achieve voltage and current balancing, there is no need to adjust other internal phase shift angles, which is beneficial to improving the stability of the entire circuit and improving the efficiency of voltage and current balancing.

[0093] See also Figure 5a , Figure 5a 1 is an inductor current timing diagram for adjusting the external phase angle of a dual active bridge conversion circuit provided by an embodiment of the present application. Figure 5a As shown, the inductor current timing diagram is a timing diagram of the output inductor current at the corresponding phase shift angle before and after adjusting the external phase shift angle of the first dual active bridge conversion circuit.

[0094] The first primary bridge arm HB1 and the first secondary bridge arm HB2 of the first dual active bridge conversion circuit can each obtain a square wave voltage and , is the voltage from HB2 to HB1, yes The corresponding maximum voltage value is yes The corresponding maximum voltage value is is the output voltage of the first dual active bridge conversion circuit, is the output inductor current of the first dual active bridge conversion circuit; For HB1 side The effective duty cycle within half a cycle, For HB2 side The effective duty cycle in half a cycle, so , Always greater than or equal to 0 and less than or equal to 1. for Lagging behind The phase shift angle is and The phase shift angle between the midpoints.

[0095] Among them, there are four waveform diagrams of the inductor current timing diagram from top to bottom. From top to bottom, the dotted line diagram in the first waveform diagram is the first primary bridge arm HB1 side of the first dual active bridge conversion circuit according to the duty cycle , and according to the outward shift phase angle and internal phase angle The waveform of the output voltage changing with time; the solid line diagram is the first primary bridge arm HB1 side according to the duty cycle , the external phase angle changes by Δ The following is a waveform diagram of the output voltage changing with time.

[0096] The second waveform is the first secondary bridge arm HB2 side of the first dual active bridge conversion circuit according to the duty cycle , and according to the outward shift phase angle and internal phase angle The output voltage waveform changes with time.

[0097] Among them, the dotted line diagram in the third waveform diagram is the first dual active bridge conversion circuit according to the external shift phase angle The waveform of the output voltage changing with time; and the solid line diagram is the waveform of the first dual active bridge conversion circuit when the external shift phase angle changes by Δ The following is a waveform diagram of the output voltage changing with time.

[0098] Among them, the dotted line diagram in the fourth waveform diagram is the first dual active bridge conversion circuit according to the external shift phase angle The waveform of the output inductor current changing with time; and the solid line diagram is the waveform of the first dual active bridge conversion circuit when the external shift phase angle changes by Δ The following is the waveform of the output inductor current changing with time.

[0099] It can be understood that in the half cycle t0~t4, when Relative position increases by Δ , that is, the duty cycle of the first secondary bridge arm HB2 of the first dual active bridge conversion circuit The waveform moves forward Δ Afterwards, the peak value of the output inductor current of the first dual active bridge conversion circuit at time t2 also increases. Therefore, within half a cycle, by changing the external shift phase angle The integral of the instantaneous value of the inductor current waveform over time is significantly increased, so the external phase shift angle Adjustment is performed to change the output power of the first dual active bridge conversion circuit and the second dual active bridge conversion circuit, that is, to change the output voltage or the output current, so as to achieve voltage and current balancing.

[0100] See also Figure 5b , Figure 5b is an inductor current timing diagram for adjusting the internal phase shift angle of the primary bridge arm provided by an embodiment of the present application. Figure 5b As shown, the inductor current timing diagram is a timing diagram of the output inductor current at the corresponding phase shift angle before and after adjusting the internal phase shift angle of the primary bridge arm of the first dual active bridge conversion circuit.

[0101] The first primary bridge arm HB1 and the first secondary bridge arm HB2 of the first dual active bridge conversion circuit can each obtain a square wave voltage and , is the voltage from HB2 to HB1, is the output voltage of the first dual active bridge conversion circuit, is the output inductor current of the first dual active bridge conversion circuit; and, For HB1 side The effective duty cycle within half a cycle, For HB2 side The effective duty cycle within half a cycle, for Lagging behind The phase shift angle is and The phase shift angle between the midpoints; and Q1 and Q4 are the first switch tube and the fourth switch tube in the first primary bridge arm, respectively, and Q5 and Q8 are the fifth switch tube and the eighth switch tube in the first secondary bridge arm, respectively. Q1 is ahead of The internal phase angle.

[0102] Among them, there are eight waveform diagrams from top to bottom in the inductor current timing diagram. From top to bottom, the first waveform diagram is a waveform diagram of the switching condition of the first switch tube Q1 in the first primary bridge arm of the first dual active bridge conversion circuit changing with time; the solid line diagram in the second waveform diagram is the fourth switch tube Q4 in the first primary bridge arm according to the internal phase shift angle The switching condition of the fourth switch tube Q4 changes with time, and the dotted line diagram is the waveform diagram of the switching condition of the fourth switch tube Q4 according to the internal phase shift angle Adjusted internal phase angle The waveform of the switching condition changing with time, the corresponding Adjust to ; The third waveform diagram is a waveform diagram showing the switching condition of the fifth switch tube Q5 in the first secondary bridge arm changing with time; the fourth waveform diagram is a waveform diagram showing the switching condition of the eighth switch tube Q8 in the first secondary bridge arm changing with time.

[0103] Among them, the solid line diagram in the fifth waveform diagram is the first primary bridge arm HB1 side of the first dual active bridge conversion circuit according to the duty cycle , and according to the outward shift phase angle and internal phase angle The output voltage changes with time; the dotted line diagram is the first primary bridge arm HB1 side according to the external phase angle , adjusted internal phase angle and the adjusted duty cycle The output voltage waveform changes with time.

[0104] Among them, the sixth waveform is the first secondary bridge arm HB2 side of the first dual active bridge conversion circuit according to the duty cycle , and according to the outward shift phase angle and internal phase angle The output voltage waveform changes with time.

[0105] Among them, the solid line diagram in the seventh waveform diagram is the first dual active bridge conversion circuit according to the internal phase shift angle The output voltage of the waveform diagram changes with time; and the dotted line diagram is the first dual active bridge conversion circuit when the internal phase shift angle changes to The following is a waveform diagram of the output voltage changing with time.

[0106] Among them, the solid line diagram in the eighth waveform diagram is the first dual active bridge conversion circuit according to the internal phase shift angle The waveform diagram of the output inductor current changing with time; and the dotted line diagram is the waveform diagram of the first dual active bridge conversion circuit when the internal phase shift angle changes to The following is the waveform of the output inductor current changing with time.

[0107] It can be understood that in the half cycle t0-t4, when the inner phase shift angle corresponding to the fourth switch tube Q4 on the first primary bridge arm HB1 side of the first dual active bridge conversion circuit is The waveform moves backward to After that, the peak value of the output inductor current of the first dual active bridge conversion circuit at time t3 also decreases, and the integral of the instantaneous value waveform of the inductor current with time is significantly reduced, so the internal phase shift angle can be Adjustment is performed to change the output power of the first dual active bridge conversion circuit and the second dual active bridge conversion circuit, that is, to change the output voltage or the output current, so as to achieve voltage and current balancing.

[0108] See also Figure 5c , Figure 5c is an inductor current timing diagram for adjusting the internal phase shift angle of the secondary bridge arm provided in an embodiment of the present application. Figure 5c As shown, the inductor current timing diagram is a timing diagram of the output inductor current at the corresponding phase shift angle before and after adjusting the internal phase shift angle of the secondary bridge arm of the first dual active bridge conversion circuit.

[0109] The first primary bridge arm HB1 and the first secondary bridge arm HB2 of the first dual active bridge conversion circuit can each obtain a square wave voltage and , is the voltage from HB2 to HB1, is the output voltage of the first dual active bridge conversion circuit, is the output inductor current of the first dual active bridge conversion circuit; and, For HB1 side The effective duty cycle within half a cycle, For HB2 side The effective duty cycle within half a cycle, for Lagging behind The phase shift angle is and The phase shift angle between the midpoints; and Q1 and Q4 are the first switch tube and the fourth switch tube in the first primary bridge arm, respectively, and Q5 and Q8 are the fifth switch tube and the eighth switch tube in the first secondary bridge arm, respectively. for Ahead of the internal phase shift angle of Q8.

[0110] Among them, there are eight waveform diagrams from top to bottom in the inductor current timing diagram. From top to bottom, the first waveform diagram is a waveform diagram of the switching condition of the first switch tube Q1 in the first primary bridge arm of the first dual active bridge conversion circuit changing with time; the second waveform diagram is a waveform diagram of the switching condition of the fourth switch tube Q4 in the first primary bridge arm changing with time; the third waveform diagram is a waveform diagram of the switching condition of the fifth switch tube Q5 in the first secondary bridge arm changing with time; the solid line diagram in the fourth waveform diagram is the switching condition of the eighth switch tube Q8 in the first secondary bridge arm according to the internal phase shift angle The switching condition of the eighth switch tube Q8 changes with time, and the dotted line diagram is the waveform diagram of the eighth switch tube Q8 according to the internal phase shift angle Adjusted internal phase angle The waveform diagram of the switching condition changing with time.

[0111] Among them, the fifth waveform is the first primary bridge arm HB1 side of the first dual active bridge conversion circuit according to the duty cycle , and according to the outward phase angle and internal phase angle The output voltage waveform changes with time.

[0112] Among them, the solid line diagram in the sixth waveform diagram is the first secondary bridge arm HB2 side of the first dual active bridge conversion circuit according to the duty cycle , and according to the outward phase angle and internal phase angle The output voltage changes with time, and the dotted line diagram is the first secondary bridge arm HB2 side according to the external phase angle , adjusted internal phase angle and the adjusted duty cycle The output voltage waveform changes with time.

[0113] Among them, the solid line diagram in the seventh waveform diagram is the first dual active bridge conversion circuit according to the internal phase shift angle The output voltage of the waveform diagram changes with time; and the dotted line diagram is the first dual active bridge conversion circuit when the internal phase shift angle changes to The following is a waveform diagram of the output voltage changing with time.

[0114] Among them, the solid line diagram in the eighth waveform diagram is the first dual active bridge conversion circuit according to the internal phase shift angle The waveform diagram of the output inductor current changing with time; and the dotted line diagram is the waveform diagram of the first dual active bridge conversion circuit when the internal phase shift angle changes to The following is the waveform of the output inductor current changing with time.

[0115] It can be understood that in the half cycle t0-t4, when the inner phase shift angle corresponding to the eighth switch tube Q8 on the first secondary bridge arm HB2 side of the first dual active bridge conversion circuit is The waveform moves backward to After that, the peak value of the output inductor current of the first dual active bridge conversion circuit at time t3 increases compared with the previous peak value at time t2, and the integral of the instantaneous value waveform of the inductor current with time also increases. Adjustment is performed to change the output power of the first dual active bridge conversion circuit and the second dual active bridge conversion circuit, that is, to change the output voltage or the output current, so as to achieve voltage and current balancing.

[0116] See also Figure 6 , Figure 6 This is a diagram of a pressure equalization ring control architecture provided by an embodiment of the present application. Figure 6 As shown, under the control of the voltage-sharing loop, the input sides of the dual active bridge conversion circuits are connected in parallel, and the output sides are connected in series.

[0117] Among them, Vref is a given voltage value, Vo_samp is a first sampling voltage on the output side of the first dual active bridge conversion circuit, and error is a voltage difference between the first sampling voltage Vo_samp and the given voltage value Vref; Q1~Q4 are switching tubes of the first primary bridge arm HB1 of the first dual active bridge conversion circuit, Q5~Q8 are switching tubes of the first secondary bridge arm HB2 of the first dual active bridge conversion circuit, Q11~Q14 are switching tubes of the second primary bridge arm HB3 of the second dual active bridge conversion circuit, and Q15~Q18 are switching tubes of the second secondary bridge arm HB4 of the second dual active bridge conversion circuit.

[0118] in, is the external phase shift angle of the first primary bridge arm HB1 and the first secondary bridge arm HB2 of the first dual active bridge conversion circuit, that is, the phase shift angle of the first switch tube Q1 in HB1 ahead of the fifth switch tube Q5 in HB2; is the internal phase shift angle of the HB1 bridge, that is, the internal phase shift angle of the first switch tube Q1 in HB1 is ahead of the fourth switch tube Q4; is the internal phase shift angle of the HB2 bridge, that is, the internal phase shift angle of the fifth switch tube Q5 in HB2 is ahead of the eighth switch tube Q8; and, For HB1 side The effective duty cycle within half a cycle, For HB2 side The effective duty cycle within half a cycle. for Lagging behind The phase shift angle is and The phase shift angle between the midpoints.

[0119] The voltage loop compensator is used to calculate the phase shift angle of the midpoint of the duty cycle of the current first dual active bridge conversion circuit according to the voltage difference between the first sampled voltage Vo_samp and the given voltage value Vref. , and according to the duty cycle and Calculate the current , , , and the result will be , , Acting on the switch tubes Q1~Q8; and, similarly, the voltage loop compensator can be used to calculate the phase shift angle of the current duty cycle midpoint of the second dual active bridge conversion circuit according to the voltage difference between the second sampling voltage and the given voltage value Vref , and according to the duty cycle and Calculate the current , , , and the result will be , , Acts on switch tubes Q11~Q18.

[0120] The PI loop can calculate the external phase angle of the current first dual active bridge conversion circuit according to the voltage difference between the first sampled voltage Vo_samp and the given voltage value Vref. The compensation value Δ , and limit the amplitude by Δ adjust ,get , and then adjust the output voltage value of the first dual active bridge conversion circuit, and, similarly, the PI loop can calculate the current external shift phase angle of the second dual active bridge conversion circuit according to the voltage difference between the second sampling voltage and the given voltage value Vref The compensation value Δ , and limit the amplitude by Δ adjust ,get , and then adjust the output voltage value of the second dual active bridge conversion circuit to achieve voltage balancing.

[0121] Specifically, the compensation value Δ is calculated by the PI loop The formula is:

[0122] Δ = (Vo_samp-Vref)+ ;

[0123] Wherein, Kp is the proportional gain, Ki is the integral gain, Vo_samp- is the first sampled voltage, and Vref is the given voltage value. Further, in addition to calculating the first dual active bridge conversion circuit and the second dual active bridge conversion circuit respectively The compensation value Δ , and then adjust In addition to realizing voltage balancing in series, the first dual active bridge conversion circuit and the second dual active bridge conversion circuit can also be calculated. The compensation value Δ , and then adjust , to achieve voltage balancing in series, or by calculating the first dual active bridge conversion circuit and the second dual active bridge conversion circuit The compensation value Δ , and then adjust , in order to achieve pressure equalization in series.

[0124] Specifically, when the controller determines to adjust or or When , the PI loop will adapt to different parameters accordingly, and get or or The corresponding compensation value. When the PI loop adapts the corresponding parameters, the phase shift angle of the primary bridge arm of the current first dual active bridge conversion circuit is calculated according to the voltage difference between the first sampled voltage Vo_samp and the given voltage value Vref. The compensation value Δ , through Δ adjust ,get ; or when the controller determines the adjustment When the PI loop adapts the corresponding parameters, the phase shift angle of the secondary bridge arm of the current first dual active bridge conversion circuit is calculated according to the voltage difference between the first sampled voltage Vo_samp and the given voltage value Vref. The compensation value Δ , through Δ adjust ,get .

[0125] Furthermore, it can be seen from the same logic that when the controller determines the adjustment When , the PI loop adapts the corresponding parameters, and calculates the phase shift angle of the primary bridge arm of the current second dual active bridge conversion circuit according to the voltage difference between the second sampling voltage and the given voltage value Vref. The compensation value Δ , through Δ adjust ,get ; or when the controller determines the adjustment When , the PI loop adapts the corresponding parameters, and calculates the phase shift angle of the secondary bridge arm of the current second dual active bridge conversion circuit according to the voltage difference between the second sampling voltage and the given voltage value Vref. The compensation value Δ , through Δ adjust ,get .

[0126] It can be seen that in this embodiment, when the first sampling voltage Vo_samp is higher than its given voltage Vref, the transmission power of the first dual active bridge conversion module is large. , or In the same way, the sampling voltage and the given voltage of the second dual active bridge conversion module can be judged to increase the output voltage of the second dual active bridge conversion module. , or , thereby increasing its output voltage and achieving voltage balancing.

[0127] See also Figure 7 , Figure 7 is a diagram of a current sharing loop control architecture provided in an embodiment of the present application. Figure 7 As shown, under the control of the current-sharing loop, the input sides of the dual active bridge conversion circuits are connected in parallel, and the output sides are connected in parallel.

[0128] Among them, Iref is a given current value, I_samp is a first sampling current on the output side of the first dual active bridge conversion circuit, and error is a current difference between the first sampling current I_samp and the given current value Iref; Q1~Q4 are switching tubes of the first primary bridge arm HB1 of the first dual active bridge conversion circuit, Q5~Q8 are switching tubes of the first secondary bridge arm HB2 of the first dual active bridge conversion circuit, Q11~Q14 are switching tubes of the second primary bridge arm HB3 of the second dual active bridge conversion circuit, and Q15~Q18 are switching tubes of the second secondary bridge arm HB4 of the second dual active bridge conversion circuit.

[0129] in, is the external phase shift angle of the first primary bridge arm HB1 and the first secondary bridge arm HB2 of the first dual active bridge conversion circuit, that is, the phase shift angle of the first switch tube Q1 in HB1 ahead of the fifth switch tube Q5 in HB2; is the internal phase shift angle of the HB1 bridge, that is, the internal phase shift angle of the first switch tube Q1 in HB1 is ahead of the fourth switch tube Q4; is the internal phase shift angle of the HB2 bridge, that is, the internal phase shift angle of the fifth switch tube Q5 in HB2 is ahead of the eighth switch tube Q8; and, For HB1 side The effective duty cycle within half a cycle, For HB2 side The effective duty cycle in half a cycle, so , Always greater than or equal to 0 and less than or equal to 1. for Lagging behind The phase shift angle is and The phase shift angle between the midpoints.

[0130] The current loop compensator is used to calculate the phase shift angle of the midpoint of the duty cycle of the current first dual active bridge conversion circuit according to the current difference between the first sampling current I_samp and the given current value Iref. , and according to the duty cycle and Calculate the current , , , and the result will be , , Acting on the switch tubes Q1~Q8; and, similarly, the current loop compensator can be used to calculate the phase shift angle of the midpoint of the current duty cycle of the second dual active bridge conversion circuit according to the current difference between the second sampling current and the given current value Iref , and according to the duty cycle and Calculate the current , , , and the result will be , , Acts on switch tubes Q11~Q18.

[0131] The PI loop can calculate the external phase angle of the current first dual active bridge conversion circuit according to the current difference between the first sampling current I_samp and the given current value Iref. The compensation value Δ , and limit the amplitude by Δ adjust ,get , and then adjust the output current value of the first dual active bridge conversion circuit; and, similarly, the PI loop can calculate the current external shift phase angle of the second dual active bridge conversion circuit according to the current difference between the second sampling current and the given current value Iref. The compensation value Δ , and limit the amplitude by Δ adjust ,get , and then adjust the output current value of the second dual active bridge conversion circuit to achieve current sharing.

[0132] Specifically, the compensation value Δ is calculated by the PI loop The formula is:

[0133]

[0134] Wherein, Kp is the proportional gain, Ki is the integral gain, I_samp is the first sampled current, and Iref is the given current value.

[0135] Further, in addition to calculating the first dual active bridge conversion circuit and the second dual active bridge conversion circuit The compensation value Δ , and then adjust In addition to realizing current sharing in parallel, the first dual active bridge conversion circuit and the second dual active bridge conversion circuit can also be calculated. The compensation value Δ , and then adjust , to achieve current sharing in parallel, or by calculating the first dual active bridge conversion circuit and the second dual active bridge conversion circuit The compensation value Δ , and then adjust , in order to achieve current sharing in parallel.

[0136] Specifically, when the controller determines to adjust or or When , the PI loop will adapt to different parameters accordingly, and get or or The corresponding compensation value. When , the PI loop adapts the corresponding parameters, and calculates the phase shift angle of the primary bridge arm of the current first dual active bridge conversion circuit according to the current difference between the first sampling current I_samp and the given current Iref. The compensation value Δ , through Δ adjust ,get ; or when the controller determines the adjustment When , the PI loop adapts the corresponding parameters, and calculates the phase shift angle of the secondary bridge arm of the current first dual active bridge conversion circuit according to the current difference between the first sampling current I_samp and the given current Iref. The compensation value Δ , through Δ adjust ,get .

[0137] Furthermore, it can be seen from the same logic that when the controller determines the adjustment When , the PI loop adapts the corresponding parameters, and calculates the phase shift angle of the primary bridge arm of the current second dual active bridge conversion circuit according to the current difference between the second sampling current and the given current Iref. The compensation value Δ , through Δ adjust ,get ; or when the controller determines the adjustment When the PI loop adapts the corresponding parameters, the phase shift angle of the secondary bridge arm of the current second dual active bridge conversion circuit is calculated according to the current difference between the second sampling current and the given current Iref. The compensation value Δ , through Δ adjust ,get .

[0138] It can be seen that in this embodiment, when the first sampling current I_samp is higher than its given current Iref, the transmission power of the first dual active bridge conversion module is large. ,or In the same way, the sampling current and the given current of the second dual active bridge conversion module can be judged to increase the output current of the second dual active bridge conversion module. ,or , thereby increasing its output current and achieving current sharing.

[0139] See also Figure 8 , Figure 8 Schematic diagram of a flow chart of a voltage and current balancing control method provided in an embodiment of the present application. The voltage and current balancing control method is applicable to Figure 1 The dual active bridge converter circuit shown in FIG. Figure 1 ,like Figure 8As shown, the voltage and current balancing control method is to achieve voltage and current balancing by adjusting the external shift phase angle of the first dual active bridge conversion module and the second dual active bridge conversion module. The voltage and current balancing control method includes the following steps: (1) powering on the power module; (2) 1. receiving a power-on instruction; 2. receiving an output voltage setting value Vo_ref; 3. switching the working mode according to a given voltage; specifically, switching the connection mode of the output ends of the first dual active bridge conversion circuit and the second dual active bridge conversion circuit in the dual active bridge conversion circuit according to the given voltage, and the connection mode includes a series mode and a parallel mode; (3) switching to work in parallel (4) Switching to series mode; (5) Detecting that the current upper sampling current I_samp1 and the lower sampling current I_samp2 are not balanced; (6) Detecting that the current upper sampling voltage Vo_samp1 and the lower sampling voltage Vo_samp2 are not balanced; (7) Determining whether the difference between I_samp1 and I_samp2 is greater than the preset current difference; if so, executing step 9; (8) Determining whether the difference between Vo_samp1 and Vo_samp2 is greater than the preset voltage difference; if so, executing step 10; (9) Reducing Δ Compensation acts on ;Specifically, Including the outer shift angle of the upper road and the outer shift angle of the lower road, Δ Including the compensation amount of the upper road outer shift angle and the compensation amount of the lower road outer shift angle; (10) Through the PI loop, Δ Compensation acts on ; (11) Determine whether the upper sampling current I_samp1 is equal to the given current Iref; if so, execute step 13, and if not, execute step 7; (12) Determine whether the upper sampling voltage Vo_samp1 is equal to the given voltage Vref; if so, execute step 14, and if not, execute step 8; (13) The strategy ends; (14) The strategy ends.

[0140] In a possible embodiment, the voltage and current balancing control method is applied to Figure 1 The dual active bridge conversion circuit shown, the method comprises:

[0141] In response to the series signal or the parallel signal of the comparison module, the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module are switched to different connection relationships through the series-parallel switching module, and the connection relationship includes a series relationship and a parallel relationship;

[0142] According to the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module, a first output value of the first dual active bridge conversion module corresponding to the connection relationship is collected, and a second output value of the second dual active bridge conversion module corresponding to the connection relationship is collected, and the output value is an output voltage value or an output current value;

[0143] Detecting whether a difference between the first output value and the second output value is greater than a preset difference, where the preset difference is a preset voltage difference or a preset current difference;

[0144] When the difference is greater than the preset difference, a first target phase shift angle is determined according to the first output value and the output given value, the output given value being an output voltage given value or an output current given value, and the first target phase shift angle is a target adjustment value corresponding to an inner phase shift angle of the primary bridge arm of the first dual-active bridge conversion module or an inner phase shift angle of the secondary bridge arm or an outer phase shift angle between the primary bridge arm and the secondary bridge arm; and a second target phase shift angle is determined according to the second output value and the output given value, the second target phase shift angle is a target adjustment value corresponding to an inner phase shift angle of the primary bridge arm of the second dual-active bridge conversion module or an inner phase shift angle of the secondary bridge arm or an outer phase shift angle between the primary bridge arm and the secondary bridge arm;

[0145] generating a first signal according to the first target phase shift angle, and generating a second signal according to the second target phase shift angle;

[0146] The first signal is sent to the first dual active bridge conversion module, and the second signal is sent to the second dual active bridge conversion module.

[0147] In a possible embodiment, according to the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module, collecting the first output value of the first dual active bridge conversion module corresponding to the connection relationship, and collecting the second output value of the second dual active bridge conversion module corresponding to the connection relationship, including:

[0148] When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, the first output voltage value of the first dual active bridge conversion module is collected by the voltage sampling module, and the second output voltage value of the second dual active bridge conversion module is collected by the voltage sampling module; and,

[0149] When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship, the first output current value of the first dual active bridge conversion module is collected through the current sampling module, and the second output current value of the second dual active bridge conversion module is collected through the voltage sampling module.

[0150] In a possible embodiment, when the difference is greater than the preset difference, determining the first target phase shift angle according to the first output value and the output given value includes:

[0151] When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, determining a first output difference value according to the difference between the first output voltage value and the output voltage given value; and

[0152] When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship, determining the first output difference value according to the difference between the first output current value and the output current given value;

[0153] Determine the current reference phase shift angle of the first dual-active bridge conversion module according to the first output difference through a compensator, wherein the reference phase shift angle is the current inner phase shift angle of the primary bridge arm of the first dual-active bridge conversion module or the current inner phase shift angle of the secondary bridge arm or the current outer phase shift angle between the primary bridge arm and the secondary bridge arm, and the compensator includes a voltage loop compensator and a current loop compensator;

[0154] Determine a target compensation value corresponding to the reference phase shift angle according to the first output difference through a PI loop;

[0155] The first target phase shift angle is determined according to the reference phase shift angle and the target compensation value.

[0156] In a possible embodiment, determining the second target phase shift angle according to the second output value and the output given value includes:

[0157] When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, determining a second output difference value according to the difference between the second output voltage value and the output voltage given value; and

[0158] When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship, determining the second output difference value according to the difference between the second output current value and the output current given value;

[0159] Determine the current reference phase shift angle of the second dual-active bridge conversion module according to the second output difference through the compensator, wherein the reference phase shift angle is the current inner phase shift angle of the primary bridge arm of the second dual-active bridge conversion module or the current inner phase shift angle of the secondary bridge arm or the current outer phase shift angle between the primary bridge arm and the secondary bridge arm;

[0160] Determine a target compensation value corresponding to the reference phase shift angle according to the second output difference through a PI loop;

[0161] The second target phase shift angle is determined according to the reference phase shift angle and the target compensation value.

[0162] It can be seen that in this embodiment, by collecting the output voltage value when the output end of the dual active bridge conversion circuit is connected in series, it is judged that there is uneven voltage, and the external phase shift angle or internal phase shift angle of the primary bridge arm and the secondary bridge arm of the dual active bridge conversion circuit is adjusted according to the output voltage value and the output voltage set value, and the output current value is collected when the output end of the dual active bridge conversion circuit is connected in parallel, so as to judge that there is uneven current, and the external phase shift angle or internal phase shift angle of the primary bridge arm and the secondary bridge arm of the dual active bridge conversion circuit is adjusted according to the output current value and the output current set value, so as to achieve equal voltage and current at the output end of the dual active bridge conversion circuit, and can directly adjust one of the external phase shift angle or the internal phase shift angle of the primary bridge arm and the secondary bridge arm without changing other phase shift angles, which is beneficial to improving the efficiency of voltage and current equalization control, reducing complexity, and improving circuit stability.

[0163] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0164] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0165] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions without departing from the spirit and scope of the present application, and can make various changes and modifications, including the combination of the above-mentioned different functions and implementation steps, including software and hardware implementation methods, all of which are within the scope of protection of the present application.

Claims

1. A dual active bridge conversion circuit, characterized in that: The dual active bridge conversion circuit includes a power supply module, a first dual active bridge conversion module, a second dual active bridge conversion module, a series-parallel switching module, a sampling module, a detection module, and a control module. The input sides of the first dual active bridge conversion module and the second dual active bridge conversion module are connected in parallel to the power supply module. The series-parallel switching module is used to switch the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module to different connection relationships, wherein the connection relationship includes a series relationship and a parallel relationship; The sampling module is used to collect, according to the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module, a first output value of the first dual active bridge conversion module corresponding to the connection relationship, and collect a second output value of the second dual active bridge conversion module corresponding to the connection relationship, wherein the output value is an output voltage value or an output current value; The detection module is used to detect whether the difference between the first output value and the second output value is greater than a preset difference, and the preset difference is a preset voltage difference or a preset current difference; The control module is used to determine a first output difference according to the first output value and an output given value when the difference is greater than the preset difference, wherein the output given value is an output voltage given value or an output current given value; and, through a compensator, determine a current first reference phase shift angle of the first dual-active bridge conversion module according to the first output difference, wherein the first reference phase shift angle is the current inner phase shift angle of the primary bridge arm of the first dual-active bridge conversion module or the current inner phase shift angle of the secondary bridge arm or the current outer phase shift angle between the primary bridge arm and the secondary bridge arm, and the compensator includes a voltage loop compensator and a current loop compensator; and, determining a target compensation value corresponding to the first reference phase shift angle according to the first output difference through a PI loop, wherein the PI loop is used to apply different parameters to determine the target compensation value corresponding to the first reference phase shift angle when the first reference phase shift angle is the inner phase shift angle or the outer phase shift angle of the first dual-active bridge conversion module; and determining a first target phase shift angle according to the first reference phase shift angle and the target compensation value, wherein the first target phase shift angle is a target adjustment value corresponding to the inner phase shift angle of the primary bridge arm or the inner phase shift angle of the secondary bridge arm or the outer phase shift angle between the primary bridge arm and the secondary bridge arm of the first dual-active bridge conversion module; and, Determine a second output difference according to the second output value and the output given value; and, determine the current second reference phase shift angle of the second dual-active bridge conversion module according to the second output difference through the compensator, the second reference phase shift angle being the current inner phase shift angle of the primary bridge arm of the second dual-active bridge conversion module or the current inner phase shift angle of the secondary bridge arm or the current outer phase shift angle between the primary bridge arm and the secondary bridge arm; determine a target compensation value corresponding to the second reference phase shift angle according to the second output difference through a PI loop, the PI loop being used to apply different parameters to determine the target compensation value corresponding to the second reference phase shift angle when the second reference phase shift angle is the inner phase shift angle or the outer phase shift angle of the second dual-active bridge conversion module; determine a second target phase shift angle according to the second reference phase shift angle and the target compensation value, the second target phase shift angle being the target adjustment value corresponding to the inner phase shift angle of the primary bridge arm of the second dual-active bridge conversion module or the inner phase shift angle of the secondary bridge arm or the outer phase shift angle between the primary bridge arm and the secondary bridge arm; and, A first signal is generated according to the first target phase shift angle, and a second signal is generated according to the second target phase shift angle; and the first signal is sent to the first dual active bridge conversion module, and the second signal is sent to the second dual active bridge conversion module.

2. The dual active bridge conversion circuit according to claim 1, characterized in that: The sampling module includes a voltage sampling module and a current sampling module, the first dual active bridge conversion module includes a first input module and a first output module, and the second dual active bridge conversion module includes a second input module and a second output module; the sampling module is connected to the first output module and the second output module respectively, wherein, The first input module includes a first primary bridge arm, the first output module includes a first secondary bridge arm, a first current sampling resistor and a first output bus capacitor, the first end of the first secondary bridge arm is connected to the second end of the first current sampling resistor, the second end of the first secondary bridge arm is connected to the first end of the first output bus capacitor, the first end of the first current sampling resistor is connected to the second end of the first output bus capacitor, and the first end of the first output bus capacitor is connected to the first end of the voltage sampling module; The second input module includes a second primary bridge arm, the second output module includes a second secondary bridge arm, a second current sampling resistor and a second output bus capacitor, the first end of the second secondary bridge arm is connected to the second end of the second current sampling resistor, the second end of the second secondary bridge arm is connected to the first end of the second output bus capacitor, the first end of the second current sampling resistor is connected to the second end of the second output bus capacitor, the first end of the second output bus capacitor is connected to the second end of the voltage sampling module, and the current sampling module is respectively connected to both ends of the first current sampling resistor and the second current sampling resistor.

3. The dual active bridge conversion circuit according to claim 2, characterized in that: The dual active bridge conversion circuit also includes a comparison module, wherein: The comparison module is used to obtain the target output voltage value of the first dual active bridge conversion module and the second dual active bridge conversion module; and, compare the target output voltage value with a preset threshold value to obtain a comparison result; and, according to the comparison result, send a series signal or a parallel signal to the series-parallel switching module.

4. The dual active bridge conversion circuit according to claim 3, characterized in that: When the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, the voltage sampling module is used to collect the first output voltage value of the first dual active bridge conversion module and the second output voltage value of the second dual active bridge conversion module; When the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship, the current sampling module is used to collect the first output current value of the first dual active bridge conversion module and the second output current value of the second dual active bridge conversion module; The detection module is used to detect whether the difference between the first output voltage value and the second output voltage value is greater than the preset voltage difference in the series relationship; and, for detecting, in the parallel relationship, whether a difference between the first output current value and the second output current value is greater than the preset current difference; The control module is used for determining the first output difference according to the first output voltage value and the output voltage given value when the difference is greater than the preset voltage difference in the series relationship; and, determining the second output difference according to the second output voltage value and the output voltage given value; and, for determining the first output difference according to the first output current value and the output current given value in the parallel relationship when the difference is greater than the preset current difference; And, the second output difference is determined according to the second output current value and the output current set value.

5. The dual active bridge conversion circuit according to claim 4, characterized in that: The series-parallel switching module includes a first switch, a second switch, a third switch and a fourth switch; the first end of the first switch is connected to the second end of the first secondary bridge arm, the second end of the first switch is connected to the second end of the second secondary bridge arm, the first end of the second switch is connected to the first end of the first secondary bridge arm, the second end of the second switch is connected to the first end of the second secondary bridge arm, the first end of the third switch is connected to the first end of the first current sampling resistor, the second end of the third switch is connected to the second end of the first output bus capacitor, the first end of the fourth switch is connected to the second end of the second secondary bridge arm, and the second end of the fourth switch is connected to the first end of the second output bus capacitor, wherein: In response to the series signal of the comparison module, the series-parallel switching module controls the first switch and the second switch to be disconnected and the third switch and the fourth switch to be closed, so that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, and, In response to the parallel signal of the comparison module, the series-parallel switching module controls the first switch and the second switch to be closed and the third switch and the fourth switch to be opened, so that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship.

6. The dual active bridge converter circuit according to claim 5, characterized in that: The switch tube of the first dual active bridge conversion module includes a first primary switch tube and a first secondary switch tube, and the switch tube of the second dual active bridge conversion module includes a second primary switch tube and a second secondary switch tube, wherein: The first primary switch tube is located in the first primary bridge arm, and the first primary switch tube includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, the first switch tube and the second switch tube are connected in series, the third switch tube and the fourth switch tube are connected in series, and the series branch of the first switch tube and the second switch tube is connected in parallel with the series branch of the third switch tube and the fourth switch tube; The first secondary switch tube is located in the first secondary bridge arm, and the first secondary switch tube includes a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube, the fifth switch tube and the sixth switch tube are connected in series, the seventh switch tube and the eighth switch tube are connected in series, and the series branch of the fifth switch tube and the sixth switch tube is connected in parallel with the series branch of the seventh switch tube and the eighth switch tube; The second primary switch tube is located in the second primary bridge arm, and the second primary switch tube includes an eleventh switch tube, a twelfth switch tube, a thirteenth switch tube and a fourteenth switch tube, the eleventh switch tube and the twelfth switch tube are connected in series, the thirteenth switch tube and the fourteenth switch tube are connected in series, and the series branch of the eleventh switch tube and the twelfth switch tube is connected in parallel with the series branch of the thirteenth switch tube and the fourteenth switch tube; The second secondary side switch tube is located at the second secondary side bridge arm, and the second secondary side switch tube includes a fifteenth switch tube, a sixteenth switch tube, a seventeenth switch tube and an eighteenth switch tube, the fifteenth switch tube and the sixteenth switch tube are connected in series, the seventeenth switch tube and the eighteenth switch tube are connected in series, and the series branch of the fifteenth switch tube and the sixteenth switch tube is connected in parallel with the series branch of the seventeenth switch tube and the eighteenth switch tube.

7. A voltage and current equalization control method, characterized in that: Applied to the dual active bridge conversion circuit according to any one of claims 1 to 6, the method comprises: The output sides of the first dual active bridge conversion module and the second dual active bridge conversion module are switched to different connection relationships through the series-parallel switching module, and the connection relationship includes a series relationship and a parallel relationship; According to the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module, a first output value of the first dual active bridge conversion module corresponding to the connection relationship is collected, and a second output value of the second dual active bridge conversion module corresponding to the connection relationship is collected, and the output value is an output voltage value or an output current value; Detecting whether a difference between the first output value and the second output value is greater than a preset difference, where the preset difference is a preset voltage difference or a preset current difference; When the difference is greater than the preset difference, a first output difference is determined according to the first output value and the output given value, wherein the output given value is an output voltage given value or an output current given value; and, a compensator is used to determine a first reference phase shift angle of the first dual-active bridge conversion module according to the first output difference, wherein the first reference phase shift angle is a current inner phase shift angle of the primary bridge arm of the first dual-active bridge conversion module or a current inner phase shift angle of the secondary bridge arm or a current outer phase shift angle between the primary bridge arm and the secondary bridge arm, wherein the compensator includes a voltage loop compensator and a current loop compensator; and, through a PI loop root Determine a target compensation value corresponding to the first reference phase shift angle according to the first output difference, the PI loop is used to apply different parameters to determine the target compensation value corresponding to the first reference phase shift angle when the first reference phase shift angle is the inner phase shift angle or the outer phase shift angle of the first dual-active bridge conversion module; and determine a first target phase shift angle according to the first reference phase shift angle and the target compensation value, the first target phase shift angle being a target adjustment value corresponding to the inner phase shift angle of the primary bridge arm or the inner phase shift angle of the secondary bridge arm or the outer phase shift angle between the primary bridge arm and the secondary bridge arm of the first dual-active bridge conversion module; and, Determine a second output difference according to the second output value and the output given value; and determine the current second reference phase shift angle of the second dual-active bridge conversion module according to the second output difference through the compensator, the second reference phase shift angle being the current inner phase shift angle of the primary bridge arm of the second dual-active bridge conversion module or the current inner phase shift angle of the secondary bridge arm or the current outer phase shift angle between the primary bridge arm and the secondary bridge arm; determine a target compensation value corresponding to the second reference phase shift angle according to the second output difference through a PI loop, the PI loop being used to apply different parameters to determine the target compensation value corresponding to the second reference phase shift angle when the second reference phase shift angle is the inner phase shift angle or the outer phase shift angle of the second dual-active bridge conversion module; determine a second target phase shift angle according to the second reference phase shift angle and the target compensation value, the second target phase shift angle being the target adjustment value corresponding to the inner phase shift angle of the primary bridge arm of the second dual-active bridge conversion module or the inner phase shift angle of the secondary bridge arm or the outer phase shift angle between the primary bridge arm and the secondary bridge arm; generating a first signal according to the first target phase shift angle, and generating a second signal according to the second target phase shift angle; The first signal is sent to the first dual active bridge conversion module, and the second signal is sent to the second dual active bridge conversion module.

8. The method according to claim 7, characterized in that The determining of the first output difference according to the first output value and the output given value comprises: When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, determining the first output difference value according to the difference between the first output voltage value and the output voltage given value; and When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship, the first output difference is determined according to the difference between the first output current value and the output current given value.

9. The method according to claim 8, characterized in that The determining of the second output difference according to the second output value and the output given value comprises: When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the series relationship, determining the second output difference value according to the difference between the second output voltage value and the output voltage given value; and When it is detected that the connection relationship between the output sides of the first dual active bridge conversion module and the second dual active bridge conversion module is the parallel relationship, the second output difference is determined according to the difference between the second output current value and the output current given value.

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