A control method, device and medium based on a dual active bridge converter

Abstract

The application discloses a control method, device and medium based on a dual active bridge converter, and the control method comprises the following steps: acquiring voltages V1 and V2 at two ends of a first power supply and a second power supply; when V1>V2, acquiring a first inner phase-shifting angle Phi1 between a first bridge arm and a second bridge arm; if Phi1<pi / 2, driving the third bridge arm to be delayed by the Phi1 angle relative to the first bridge arm, and if Phi1>=pi / 2, driving the third bridge arm to be delayed by pi / 2 angle relative to the first bridge arm; when V1V2, acquiring a second inner phase-shifting angle Phi2 between a third bridge arm and a fourth bridge arm; if Phi2<pi / 2, driving the first bridge arm to be delayed by the Phi2 angle relative to the third bridge arm, and if Phi2>=pi / 2, driving the first bridge arm to be delayed by pi / 2 angle relative to the third bridge arm. The control method, device and medium based on the dual active bridge converter provided by the application realize zero-voltage switching and zero-current switching of the circuit under light load and heavy load conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of converters, and in particular relates to a control method, device and medium based on a dual active bridge converter. Background Art

[0002] The dual active bridge converter (Dual Active Bridge Converter DAB) has been widely studied and applied because it can realize bidirectional energy transmission and topology with built-in isolation characteristics. It mainly consists of an input side full-bridge converter, an output side full-bridge converter and a high-frequency transformer.

[0003] In practical applications, when the voltage ratio on both sides of the dual active bridge converter is significantly different or under light load conditions, current peaks and increased reflux power are likely to occur. In this case, soft opening of the circuit cannot be achieved, that is, the load is not disconnected and connected suddenly. The changes in voltage and current are both process quantities, and there are certain switching losses. Therefore, how to achieve soft opening under different operating conditions, that is, to achieve zero voltage switching and zero current switching, is an urgent problem to be solved. Summary of the Invention

[0004] The present invention provides a control method, device and medium based on a dual active bridge converter, which are used to solve the problem of how to achieve zero voltage switching and zero current switching.

[0005] In order to solve the above technical problems, the present invention provides a dual active bridge converter, comprising a primary full-bridge circuit, a secondary full-bridge circuit, and a transformer arranged between the primary full-bridge circuit and the secondary full-bridge circuit;

[0006] The primary full-bridge circuit includes a first bridge arm and a second bridge arm, the first bridge arm includes a first switching device and a third switching device connected in series, and the second bridge arm includes a second switching device and a fourth switching device connected in series.

[0007] The secondary full-bridge circuit includes a third bridge arm and a fourth bridge arm, the third bridge arm includes a fifth switching device and a seventh switching device connected in series, and the fourth bridge arm includes a sixth switching device and an eighth switching device connected in series.

[0008] Furthermore, it also includes a sampling inductor L1, the same-name end of the primary winding of the transformer is connected to the midpoint of the first bridge arm through the sampling inductor L1, and the opposite-name end of the primary winding of the transformer is connected to the midpoint of the second bridge arm;

[0009] The like-name end of the secondary winding of the transformer is connected to the midpoint of the third bridge arm, and the unlike-name end of the secondary winding of the transformer is connected to the midpoint of the fourth bridge arm.

[0010] Furthermore, it also includes a first power supply and a second power supply;

[0011] The first bridge arm and the second bridge arm are connected in parallel with the first power supply, and the third bridge arm and the fourth bridge arm are connected in parallel with the second power supply.

[0012] Furthermore, the first switching device, the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device, the seventh switching device and the eighth switching device are all field effect transistors, and both ends of each field effect transistor are connected in reverse parallel with a corresponding diode.

[0013] Further, the driving signals of the first switching device and the third switching device, the second switching device and the fourth switching device, the fifth switching device and the seventh switching device, and the sixth switching device and the eighth switching device are respectively a set of complementary signals with a duty cycle of 50%.

[0014] Based on the above dual active bridge converter, the present invention further provides a control method based on the dual active bridge converter, the method comprising:

[0015] Obtain voltages V1 and V2 across the first power source and the second power source;

[0016] When V1>V2, obtain a first internal phase shift angle Φ1 between the first bridge arm and the second bridge arm; if Φ1<π / 2, drive the third bridge arm to delay the angle Φ1 relative to the first bridge arm; if Φ1≥π / 2, drive the third bridge arm to delay the angle π / 2 relative to the first bridge arm;

[0017] When V1 is less than V2, a second inner phase shift angle Φ2 between the third bridge arm and the fourth bridge arm is obtained; if Φ2 is less than π / 2, the first bridge arm is driven to be delayed by the Φ2 angle relative to the third bridge arm; if Φ2 is greater than or equal to π / 2, the first bridge arm is driven to be delayed by the π / 2 angle relative to the third bridge arm.

[0018] Furthermore, the first inner phase shift angle Φ1≤π, and the second inner phase shift angle Φ2≤π.

[0019] Furthermore, after obtaining the voltages V1 and V2 across the first power source and the second power source, the method further includes:

[0020] When V1>V2, the current value IL of the sampling inductor L1 at the same moment as the second inner phase shift angle Φ2 is obtained;

[0021] If IL>0, increase the second inner phase shift angle Φ2; if IL<0, reduce the second inner phase shift angle Φ2, so that the current value IL of the sampling inductor L1 at the moment of the second inner phase shift angle Φ2 is 0;

[0022] When V1<V2, obtaining the current value IL of the sampling inductor L1 at the same moment as the first inner phase shift angle Φ1;

[0023] If IL>0, the first internal phase shift angle Φ1 is increased; if IL<0, the first internal phase shift angle Φ1 is decreased, so that the current value IL of the sampling inductor L1 is 0 at the same time as the first internal phase shift angle Φ1.

[0024] The present invention also provides a control device based on a dual active bridge converter, comprising a processor and a memory, wherein:

[0025] The memory is used to store computer programs;

[0026] The processor is configured to read the computer program in the memory and execute the steps of any one of the above control methods based on a dual active bridge converter.

[0027] The present invention also provides a computer-readable storage medium having a readable computer program stored thereon, which, when executed by a processor, implements the steps of any of the above-mentioned control methods based on a dual active bridge converter.

[0028] Compared with the prior art, the present invention provides a control method, device and medium based on a dual active bridge converter, which obtains a first internal phase shift angle between the first bridge arm and the second bridge arm, adjusts the delayed phase angle of the third bridge arm relative to the first bridge arm, or obtains a second internal phase shift angle between the third bridge arm and the fourth bridge arm, adjusts the delayed phase angle of the first bridge arm relative to the third bridge arm, and also obtains the current value of the sampling inductor at the same time as the second internal phase shift angle. By adjusting the angle of the second internal phase shift angle, the current value of the sampling inductor at the same time as the second internal phase shift angle is made to be 0, thereby achieving zero voltage switching and zero current switching of the circuit under both light load and heavy load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only part of the embodiments of the present invention, rather than all the embodiments. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings are all within the scope of protection of this application.

[0030] Figure 11 is a schematic structural diagram of a dual active bridge converter provided by an embodiment of the present invention;

[0031] Figure 2 is a flow chart of a control method based on a dual active bridge converter provided by an embodiment of the present invention;

[0032] Figure 3 This is a process flow of a control method based on a dual active bridge converter provided by an embodiment of the present invention. Figure 2 ;

[0033] Figure 4 This is a control block diagram of a first inner phase shift angle Φ1 of a dual active bridge converter provided by an embodiment of the present invention;

[0034] Figure 5 This is a control block diagram of a second inner phase shift angle Φ2 of a dual active bridge converter provided by an embodiment of the present invention;

[0035] Figure 6 This is a mode of a dual active bridge converter under light load provided by an embodiment of the present invention. Figure 1 ;

[0036] Figure 7 This is a mode of a dual active bridge converter under light load provided by an embodiment of the present invention. Figure 2 ;

[0037] Figure 8 This is a timing diagram of a dual active bridge converter under light load provided by an embodiment of the present invention;

[0038] Figure 9 This is a mode of a dual active bridge converter under heavy load provided by an embodiment of the present invention. Figure 1 ;

[0039] Figure 10 This is a mode of a dual active bridge converter under heavy load provided by an embodiment of the present invention. Figure 2 ;

[0040] Figure 11 This is a timing diagram of a dual active bridge converter under heavy load provided by an embodiment of the present invention;

[0041] Figure 12 1 is a schematic structural diagram of a control device based on a dual active bridge converter provided by an embodiment of the present invention;

[0042] Figure 13 It is a structural diagram of a computer-readable storage medium provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] In order to make the description of the present disclosure more detailed and complete, the following is an illustrative description of the implementation methods and specific examples of the present invention; however, this is not the only form of implementing or using the specific embodiments of the present invention. The implementation methods cover the features of multiple specific embodiments and the method steps and their sequence for constructing and operating these specific embodiments. However, other specific embodiments can also be used to achieve the same or equal functions and step sequences. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0045] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be practiced in an order other than that illustrated or described herein.

[0046] In the description of the embodiments of the present invention, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is merely a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two, and other quantifiers are similar. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention, and the embodiments of the present application and the features in the embodiments can be combined with each other unless there is a conflict.

[0047] Please refer to Figures 1-11 The present invention provides a control method based on a dual active bridge converter to solve the problem of how to achieve zero voltage switching and zero current switching. Figure 1 FIG. 1 is a schematic diagram of a dual active bridge converter according to an embodiment of the present invention. The dual active bridge converter comprises a primary full bridge circuit, a secondary full bridge circuit, and a transformer T1 disposed between the primary full bridge circuit and the secondary full bridge circuit. Figure 1 The full-bridge circuit in the middle left half specifically includes the first bridge arm and the second bridge arm, and the secondary full-bridge circuit is Figure 1The full-bridge circuit in the middle right half includes the third bridge arm and the fourth bridge arm, and the transformer T1 is Figure 1 The part between the primary side full-bridge circuit and the secondary side full-bridge circuit can be set as an isolated high-frequency transformer with an n:1 turns ratio in specific applications, where n is a positive real number.

[0048] In an embodiment of the present invention, the first bridge arm includes a first switching device SIC1 and a third switching device SIC3 connected in series, the second bridge arm includes a second switching device SIC2 and a fourth switching device SIC4 connected in series, the third bridge arm includes a fifth switching device SIC5 and a seventh switching device SIC7 connected in series, and the fourth bridge arm includes a sixth switching device SIC6 and an eighth switching device SIC8 connected in series.

[0049] Specifically, the first switching device SIC1, the second switching device SIC2, the third switching device SIC3, the fourth switching device SIC4, the fifth switching device SIC5, the sixth switching device SIC6, the seventh switching device SIC7, and the eighth switching device SIC8 are all common high-frequency switching tubes. For example, in a specific embodiment provided by the present invention, each of the above-mentioned switching devices is specifically set to a field-effect tube, and a diode is connected in reverse parallel at both ends of each field-effect tube. In this case, the first bridge arm includes the first field-effect tube Q1 and the third field-effect tube Q3, the second bridge arm includes the second field-effect tube Q2 and the fourth field-effect tube Q4, the third bridge arm includes the fifth field-effect tube Q5 and the seventh field-effect tube Q7, and the fourth bridge arm includes the sixth field-effect tube Q6 and the eighth field-effect tube Q8, and the corresponding diode is connected in reverse parallel at both ends of each field-effect tube.

[0050] In the embodiment of the present invention, a sampling inductor L1 is also included. Please continue to refer to Figure 1 The same-name ends of the primary winding of the transformer T1 are connected to the midpoint of the first bridge arm through the sampling inductor L1. It should be noted that the connection to the midpoint here does not specifically refer to the specific midpoint position of the first bridge arm, but is connected to the connection line between the first field-effect transistor Q1 and the third field-effect transistor Q3, and the connection point is marked as a; the opposite-name ends of the primary winding of the transformer T1 are connected to the midpoint of the second bridge arm, and the connection point is marked as b; the same-name ends of the secondary winding of the transformer T1 are connected to the midpoint of the third bridge arm, and the connection point is marked as c; the opposite-name ends of the secondary winding of the transformer T1 are connected to the midpoint of the fourth bridge arm, and the connection point is marked as d; as for the specific meanings of the midpoints of the second bridge arm, the midpoints of the third bridge arm, and the midpoints of the fourth bridge arm, please refer to the description of the midpoint of the first bridge arm. No further explanation is given here. As long as the above-mentioned connection relationship can be achieved, it is feasible.

[0051] Furthermore, the dual active bridge converter provided in the embodiment of the present invention further includes a first power supply and a second power supply. Please continue to refer to Figure 1The first power supply and the second power supply can be specifically set as two groups of batteries Battery1 and Battery2; specifically, the first bridge arm and the second bridge arm are connected in parallel with the first power supply, and the third bridge arm and the fourth bridge arm are connected in parallel with the second power supply, and there is a certain voltage difference between the first power supply and the second power supply.

[0052] In the embodiment of the present invention, the first switching device SIC1 and the third switching device SIC3 form a pair of transistors that drive a set of complementary signals with a duty cycle of 50% to complement each other and conduct. The second switching device SIC2 and the fourth switching device SIC4 form a pair of transistors that drive a set of complementary signals with a duty cycle of 50% to complement each other and conduct. The fifth switching device SIC5 and the seventh switching device SIC7 form a pair of transistors that drive a set of complementary signals with a duty cycle of 50% to complement each other and conduct. The sixth switching device SIC6 and the eighth switching device SIC8 form a pair of transistors that also drive a set of complementary signals with a duty cycle of 50% to complement each other and conduct.

[0053] Based on the above dual active bridge converter, please refer to Figure 2 , is a flow chart of a control method based on a dual active bridge converter provided by an embodiment of the present invention, the control method specifically comprising the following steps:

[0054] Step S1: obtaining voltages V1 and V2 across the first power source and the second power source;

[0055] In the embodiment of the present invention, there is a voltage difference between Battery 1 and Battery 2. Therefore, by obtaining the voltages V1 and V2 across Battery 1 and Battery 2, the on / off state of each field effect transistor provided on each bridge arm is determined.

[0056] Step S2: When V1>V2, obtain a first internal phase shift angle Φ1 between the first bridge arm and the second bridge arm; if Φ1<π / 2, drive the third bridge arm to delay the angle Φ1 relative to the first bridge arm; if Φ1≥π / 2, drive the third bridge arm to delay the angle π / 2 relative to the first bridge arm;

[0057] When V1 is less than V2, a second inner phase shift angle Φ2 between the third bridge arm and the fourth bridge arm is obtained; if Φ2 is less than π / 2, the first bridge arm is driven to be delayed by the Φ2 angle relative to the third bridge arm; if Φ2 is greater than or equal to π / 2, the first bridge arm is driven to be delayed by the π / 2 angle relative to the third bridge arm.

[0058] In an embodiment of the present invention, the first bridge arm of the primary full-bridge circuit is specified as the leading arm, the second bridge arm of the primary full-bridge circuit is specified as the lagging arm, the phase angle between the first bridge arm and the second bridge arm is the first inner phase shift angle Φ1, and the voltage between points a and b is adjusted by adjusting the first inner phase shift angle Φ1 between the leading arm and the lagging arm; the phase angle between the third bridge arm and the fourth bridge arm is specified as the second inner phase shift angle Φ2, and the voltage between points c and d is adjusted by adjusting the second inner phase shift angle Φ2 between the third bridge arm and the fourth bridge arm.

[0059] Furthermore, when the voltage across the first power supply is greater than the voltage across the second power supply, that is, V1>V2, energy is transferred from left to right. At this time, it is necessary to obtain the first internal phase shift angle Φ1 between the first bridge arm and the second bridge arm. If the first internal phase shift angle Φ1 is less than π / 2, the third bridge arm is driven to shift the phase by the above Φ1 angle relative to the first bridge arm, which can also be understood as delaying the above Φ1 angle. If the first internal phase shift angle Φ1 is greater than or equal to π / 2, the third bridge arm is driven to directly delay by π / 2 angle relative to the first bridge arm.

[0060] When the voltage across the first power supply is less than the voltage across the second power supply, that is, V1 < V2, energy is transferred from right to left, which is exactly the opposite of the above-mentioned process of energy transfer from left to right. At this time, it is necessary to obtain a second inner phase shift angle Φ2 between the third bridge arm and the fourth bridge arm; if the second inner phase shift angle Φ2 < π / 2, the first bridge arm is driven to shift the phase by the above Φ2 angle relative to the third bridge arm, which can also be understood as delaying the above Φ2 angle. If the second inner phase shift angle Φ2 is greater than or equal to π / 2, the first bridge arm is driven to delay the third bridge arm by an angle of π / 2.

[0061] In the embodiment of the present invention, obtaining the first inner phase shift angle Φ1 between the first bridge arm and the second bridge arm, and obtaining the second inner phase shift angle Φ2 between the third bridge arm and the fourth bridge arm are different choices made according to the voltage conditions at both ends of the circuit. If V1>V2, it is necessary to ensure that the maximum value of the first inner phase shift angle Φ1 does not exceed π. If V1<V2, it is necessary to ensure that the maximum value of the second inner phase shift angle Φ2 does not exceed π.

[0062] Please refer to Figure 4, which is a control block diagram of the first internal phase shift angle Φ1 of a dual active bridge converter provided by an embodiment of the present invention. In the figure, Vref is the voltage setting value, Vback is the voltage feedback value, Verr is the voltage deviation value, Iref is the current setting value (the output value of the voltage PI controller), Ierr is the current deviation value, Iback is the current feedback value, Φ1 is the first internal phase shift angle between the first bridge arm and the second bridge arm, and the current setting value of the current PI regulator is output through the voltage PI regulator according to the voltage setting value and the voltage feedback value. It should be noted that when the current setting value output by the voltage PI regulator exceeds the maximum current limit set by the circuit, the maximum current limit is output at this time to prevent the circuit from being burned out by excessive current. Then, the first internal phase shift angle Φ1 value is obtained according to the current setting value and the current feedback value at the input end of the current PI regulator, thereby obtaining the required phase angle value. If V1 is less than V2, the process of obtaining the second internal phase shift angle Φ2 value is the same as above, and the present invention will not elaborate on this.

[0063] It should be noted that the PI (proportional integral controller) regulator is a linear controller that forms a control deviation based on a given value and an actual output value, and forms a control quantity by linearly combining the proportion and integral of the deviation to control the controlled object. As for how to connect the above-mentioned voltage PI regulator and current PI regulator to the dual active bridge converter and how to obtain the required relevant data, these are common knowledge widely used by those skilled in the art, so the present invention will not elaborate on this.

[0064] Afterwards, the waveform modulator can be further used to obtain the driving waveforms of the first switching device SIC1 and the third switching device SIC3, and the driving waveforms of the second switching device SIC2 and the fourth switching device SIC4, so as to more intuitively obtain the first internal phase shift angle Φ1 between the first bridge arm and the second bridge arm. Before obtaining the first internal phase shift angle Φ1 between the first bridge arm and the second bridge arm, it is necessary to first ensure that the first internal phase shift angle Φ1 ≤ π through the voltage PI regulator and the current PI regulator.

[0065] It should be noted that when V1<V2, the process of regulating the circuit through the second inner phase shift angle Φ2 is the same as the first inner phase shift angle Φ1, which will not be elaborated in detail in the present invention.

[0066] For further information, please refer to Figure 3 , which is a process flow of a control method based on a dual active bridge converter provided by an embodiment of the present invention Figure 2 , that is, how to achieve current zero-crossing point regulation through the first inner phase shift angle Φ1 or the second inner phase shift angle Φ2, specifically including the following steps:

[0067] S3: When V1>V2, obtain the current value IL of the sampling inductor L1 at the same time as the second inner phase shift angle Φ2; if IL>0, increase the second inner phase shift angle Φ2; if IL<0, reduce the second inner phase shift angle Φ2, so that the current value IL of the sampling inductor L1 at the same time as the second inner phase shift angle Φ2 is 0;

[0068] When V1<V2, obtain the current value IL of the sampling inductor L1 at the same moment as the first inner phase shift angle Φ1; if IL>0, increase the first inner phase shift angle Φ1; if IL<0, reduce the first inner phase shift angle Φ1, so that the current value IL of the sampling inductor L1 at the same moment as the first inner phase shift angle Φ1 is 0.

[0069] Please refer to further Figure 5 , which is a control block diagram of a second inner phase shift angle Φ2 of a dual active bridge converter provided by an embodiment of the present invention, Figure 5 Taking the second inner phase shift angle Φ2 as an example, the control block diagram of the first inner phase shift angle Φ1 is the same as the second inner phase shift angle Φ2, and the present invention will not elaborate on it in detail; specifically, in the figure, Ilerr is the inductor current deviation value, and ILback is the feedback current of the inductor L1 at the second inner phase shift angle Φ2.

[0070] In the embodiment of the present invention, when V1>V2, it is necessary to obtain the current value IL of the sampling inductor L1 at the same time as the second inner phase shift angle Φ2. Then, if IL>0, the second inner phase shift angle Φ2 is increased. If IL<0, the second inner phase shift angle Φ2 is decreased, so that the current value IL of the sampling inductor L1 at the same time as the second inner phase shift angle Φ2 is 0.

[0071] Furthermore, when the current value IL of the sampling inductor L1 is greater than 0, the second inner phase shift angle Φ2 is increased by the above-mentioned zero-point current PI controller. When the current value IL of the sampling inductor L1 is less than 0, the second inner phase shift angle Φ2 is reduced by the above-mentioned zero-point current PI controller to ensure that the inductor current IL just passes through the zero point at the second inner phase shift angle Φ2, that is, IL=0.

[0072] The above process of increasing or decreasing the second inner phase shift angle Φ2 to ensure that IL=0 at the same moment as the second inner phase shift angle Φ2 when V1>V2 should be distinguished from the process of achieving the current value IL=0 of the sampling inductor L1 at the same moment as the first inner phase shift angle Φ1 when V1<V2 by using the first inner phase shift angle Φ1. For details, please refer to Figure 3 .

[0073] Furthermore, the control methods described in steps S2 and S3 are now integrated accordingly. That is, when V1>V2, it is necessary to first obtain a first internal phase shift angle Φ1 between the first bridge arm and the second bridge arm; if Φ1<π / 2, the third bridge arm is driven to delay the angle Φ1 relative to the first bridge arm; if Φ1≥π / 2, the third bridge arm is driven to delay the angle π / 2 relative to the first bridge arm; then, a second internal phase shift angle Φ2 between the third bridge arm and the fourth bridge arm is obtained, and the current value IL of the sampling inductor L1 at the same moment as the second internal phase shift angle Φ2 is obtained; if IL>0, the second internal phase shift angle Φ2 is increased; if IL<0, the second internal phase shift angle Φ2 is decreased, so that the current value IL of the sampling inductor L1 at the same moment as the second internal phase shift angle Φ2 is 0.

[0074] When V1 is less than V2, it is necessary to first obtain a second inner phase shift angle Φ2 between the third bridge arm and the fourth bridge arm; if Φ2 is less than π / 2, the first bridge arm is driven to delay the first bridge arm by the angle Φ2 relative to the third bridge arm; if Φ2 is greater than or equal to π / 2, the first bridge arm is driven to delay the first bridge arm by the angle π / 2 relative to the third bridge arm; then, the first inner phase shift angle Φ1 between the first bridge arm and the second bridge arm is obtained, and the current value IL of the sampling inductor L1 at the same moment as the first inner phase shift angle Φ1 is obtained; if IL is greater than 0, the first inner phase shift angle Φ1 is increased; if IL is less than 0, the first inner phase shift angle Φ1 is decreased, so that the current value IL of the sampling inductor L1 at the same moment as the first inner phase shift angle Φ1 is 0.

[0075] It should be noted that in actual applications, the order of the above steps S2 and S3 can be adjusted forward and backward, or they can be performed simultaneously. The embodiment of the present invention does not impose too many restrictions on this, but should make corresponding distinctions between the specific control methods when V1>V2 and V1<V2.

[0076] For further information, please refer to Figure 6-Figure 8 Through the above dual active bridge converter and its control method, the modal diagram and timing diagram of the converter under light load are obtained. Light load is relative to full load, which means that the load rate is below 30% within the load range of the circuit. Assuming that the energy is transferred from the first power supply to the second power supply under light load, please refer to Figure 6 and Figure 7 The above two figures are respectively the modes of a dual active bridge converter provided by an embodiment of the present invention when lightly loaded. Figure 1 and modal Figure 2From the modal diagram, we can see that: at time t0-t1, the first FET Q1 and the fourth FET Q4 are turned on, and the seventh FET Q7 and the eighth FET Q8 are turned on; at time t1-t2, the first FET Q1 and the second FET Q2 are turned on, and the fifth FET Q5 and the eighth FET Q8 are turned on; at time t2-t3, the first FET Q1 and the second FET Q2 are turned on, and the fifth FET Q5 and the sixth FET Q6 are turned on; at time t3-t4, the second FET Q2 and the third FET Q3 are turned on, and the fifth FET Q5 and the sixth FET Q6 are turned on; at time t4-t5, the third FET Q3 and the fourth FET Q4 are turned on, and the sixth FET Q6 and the seventh FET Q7 are turned on; at time t5-t6, the third FET Q3 and the fourth FET Q4 are turned on, and the seventh FET Q7 and the eighth FET Q8 are turned on.

[0077] Please continue to refer to Figure 8 , is a timing diagram of a dual active bridge converter under light load provided by an embodiment of the present invention, where Vab represents the voltage between points a and b, Vcd represents the voltage between points c and d, VL1 represents the voltage across the sampling inductor L1, and IL1 represents the current in the sampling inductor L1. Specifically, in the figure, times t1 and t4 are the time points of the first inner phase shift angle Φ1 between the first bridge arm and the second bridge arm, and times t2 and t5 are the time points of the second inner phase shift angle Φ2. This ensures that the inductor current IL just crosses zero at the second inner phase shift angle Φ2, at which time IL = 0.

[0078] At the same time, we can observe that zero current switching is achieved at the switching points t0, t2, t3, and t5, and zero voltage switching is achieved at the switching points t1 and t4. That is, the dual active bridge converter and the control method thereof disclosed in the embodiment of the present invention achieve zero voltage switching and zero current switching under light load conditions without energy backflow, and further achieve the minimum current peak value and minimum current effective value under light load conditions.

[0079] Please refer to further Figures 9-11 , the modal diagram and timing diagram of the converter under heavy load are obtained by using the above dual active bridge converter and its control method. Heavy load means that the load rate is above 80% within the load range of the circuit. Please continue to refer to Figure 9 and Figure 10 The above two figures are respectively the modes of a dual active bridge converter under heavy load provided by an embodiment of the present invention. Figure 1 and modal Figure 2, assuming that energy is transferred from the first power supply to the second power supply, it can be seen from the modal diagram that: at t0-t1, the first field effect transistor Q1 and the fourth field effect transistor Q4 are turned on, and the sixth field effect transistor Q6 and the seventh field effect transistor Q7 are turned on; at t1-t2, the first field effect transistor Q1 and the fourth field effect transistor Q4 are turned on, and the seventh field effect transistor Q7 and the eighth field effect transistor Q8 are turned on; at t2-t3, the first field effect transistor Q1 and the fourth field effect transistor Q4 are turned on, and the fifth field effect transistor Q5 and the eighth field effect transistor Q8 are turned on; at t3-t4, the first field effect transistor Q1 and the second field effect transistor Q2 are turned on, and the fifth field effect transistor Q At t4-t5, the second field effect transistor Q2 and the third field effect transistor Q3 are turned on, the fifth field effect transistor Q5 and the eighth field effect transistor Q8 are turned on. At t5-t6, the second field effect transistor Q2 and the third field effect transistor Q3 are turned on, the fifth field effect transistor Q5 and the sixth field effect transistor Q6 are turned on. At t6-t7, the second field effect transistor Q2 and the third field effect transistor Q3 are turned on, the sixth field effect transistor Q6 and the seventh field effect transistor Q7 are turned on. At t7-t8, the third field effect transistor Q3 and the fourth field effect transistor Q4 are turned on, and the sixth field effect transistor Q6 and the seventh field effect transistor Q7 are turned on.

[0080] Please continue to refer to Figure 11 , is a timing diagram of a dual active bridge converter under heavy load provided by an embodiment of the present invention, where Vab represents the voltage between points a and b, Vcd represents the voltage between points c and d, VL1 represents the voltage across the sampling inductor L1, and IL1 represents the current of the sampling inductor L1. Specifically, in the figure, the first inner phase shift angle Φ1 between the first bridge arm and the second bridge arm is at time points t3 and t7, and the second inner phase shift angle Φ2 is at time points t1 and t5. This ensures that the inductor current IL just crosses zero at the second inner phase shift angle Φ2, at which time IL = 0.

[0081] We can observe that zero current switching is achieved at the switching points t1 and t5, and zero voltage switching is achieved at the switching points t0, t2, t3, t4, t6, and t7. That is, the dual active bridge converter and the control method thereof disclosed in the embodiment of the present invention also achieve zero voltage switching and zero current switching under heavy load conditions, that is, soft opening of the circuit is achieved.

[0082] It should be noted that the above Figures 6-11 The modal and timing analyses are all performed on the dual active bridge converter when V1>V2. When V1<V2, the present invention has been described in detail in the above steps S2-S3, so no further details will be given here.

[0083] Based on the control method of the dual active bridge converter, Figure 121 is a schematic diagram of the structure of a control device based on a dual active bridge converter according to an embodiment of the present invention. The identification device includes a processor 1201 and a memory 1202 coupled to the processor 1202. The memory 1202 stores a computer program. When the computer program is executed by the processor 1201, the processor 1201 performs the steps of the control method of the dual active bridge converter according to the above embodiment.

[0084] For other details about how the processor 1201 in the control device based on the dual active bridge converter implements the above technical solution, please refer to the description of the control method of the dual active bridge converter provided in the above invention embodiment, which will not be repeated here.

[0085] Among them, the processor 1201 can also be called a CPU (Central Processing Unit), and the processor 1201 may be an integrated circuit chip with signal processing capabilities; the processor 1201 can also be a general-purpose processor, DSP (Digital Signal Process), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, among which the general-purpose processor can be a microprocessor or the processor 1201 can also be any conventional processor, etc.

[0086] like Figure 13 As shown, an embodiment of the present invention further provides a schematic diagram of the structure of a computer-readable storage medium, on which a readable computer program 1301 is stored; wherein, the computer program 1301 can be stored in the above-mentioned storage medium in the form of a software product, including a number of instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk, a ROM (Read-Only Memory), a RAM (Random Access Memory), and other media that can store program code, or a terminal device such as a computer, server, mobile phone, or tablet.

[0087] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0088] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0089] The present invention provides a control method, device, and medium based on a dual active bridge converter. The method obtains a first internal phase shift angle between a first bridge arm and a second bridge arm, adjusts the delayed phase angle of the third bridge arm relative to the first bridge arm, or obtains a second internal phase shift angle between the third bridge arm and a fourth bridge arm, adjusts the delayed phase angle of the first bridge arm relative to the third bridge arm, and further obtains the current value of the sampling inductor at the same moment as the second internal phase shift angle. By adjusting the angle of the second internal phase shift angle, the current value of the sampling inductor at the same moment as the second internal phase shift angle is set to zero, thereby achieving zero voltage switching and zero current switching of the circuit under both light load and heavy load conditions.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A control method for a dual active bridge converter, applied to a dual active bridge converter, characterized in that: The dual active bridge converter includes a primary full-bridge circuit, a secondary full-bridge circuit, and a transformer arranged between the primary full-bridge circuit and the secondary full-bridge circuit; The primary full-bridge circuit includes a first bridge arm and a second bridge arm, the first bridge arm includes a first switching device and a third switching device connected in series, and the second bridge arm includes a second switching device and a fourth switching device connected in series. The secondary full-bridge circuit includes a third bridge arm and a fourth bridge arm, the third bridge arm includes a fifth switching device and a seventh switching device connected in series, and the fourth bridge arm includes a sixth switching device and an eighth switching device connected in series; The device further includes a sampling inductor L1, wherein the like-name end of the primary winding of the transformer is connected to the midpoint of the first bridge arm through the sampling inductor L1, and the opposite-name end of the primary winding of the transformer is connected to the midpoint of the second bridge arm; the like-name end of the secondary winding of the transformer is connected to the midpoint of the third bridge arm, and the opposite-name end of the secondary winding of the transformer is connected to the midpoint of the fourth bridge arm; It also includes a first power supply and a second power supply; the first bridge arm and the second bridge arm are connected in parallel with the first power supply, and the third bridge arm and the fourth bridge arm are connected in parallel with the second power supply; The control method comprises the following steps: Obtain voltages V1 and V2 across the first power source and the second power source; When V1>V2, a first inner phase shift angle Φ1 between the first bridge arm and the second bridge arm is obtained; If Φ1<π / 2, driving the third bridge arm to be delayed by the angle Φ1 relative to the first bridge arm; if Φ1≥π / 2, driving the third bridge arm to be delayed by the angle π / 2 relative to the first bridge arm; When V1 is less than V2, a second inner phase shift angle Φ2 between the third bridge arm and the fourth bridge arm is obtained; if Φ2 is less than π / 2, the first bridge arm is driven to be delayed by the angle Φ2 relative to the third bridge arm; if Φ2 is greater than or equal to π / 2, the first bridge arm is driven to be delayed by the angle π / 2 relative to the third bridge arm; After obtaining the voltages V1 and V2 at both ends of the first power supply and the second power supply, the method further includes: When V1>V2, the current value IL of the sampling inductor L1 at the same moment as the second inner phase shift angle Φ2 is obtained; If IL>0, increase the second inner phase shift angle Φ2; if IL<0, reduce the second inner phase shift angle Φ2, so that the current value IL of the sampling inductor L1 at the moment of the second inner phase shift angle Φ2 is 0; When V1<V2, obtaining the current value IL of the sampling inductor L1 at the same moment as the first inner phase shift angle Φ1; If IL>0, the first internal phase shift angle Φ1 is increased; if IL<0, the first internal phase shift angle Φ1 is decreased, so that the current value IL of the sampling inductor L1 is 0 at the same time as the first internal phase shift angle Φ1.

2. The control method of a dual active bridge converter according to claim 1, wherein: The first inner phase shift angle Φ1≤π, and the second inner phase shift angle Φ2≤π.

3. The control method of a dual active bridge converter according to claim 1, wherein: The first switching device, the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device, the seventh switching device and the eighth switching device provided in the dual active bridge converter are all field effect transistors, and both ends of each field effect transistor are connected in reverse parallel with a corresponding diode.

4. The control method of a dual active bridge converter according to claim 1, wherein: The driving signals of the first switching device and the third switching device, the second switching device and the fourth switching device, the fifth switching device and the seventh switching device, and the sixth switching device and the eighth switching device provided in the dual active bridge converter are respectively a set of complementary signals with a duty cycle of 50%.

5. A control device based on a dual active bridge converter, characterized in that: comprising a processor and a memory, wherein: The memory is used to store computer programs; The processor is configured to read the computer program in the memory and execute the steps of the control method for a dual active bridge converter according to any one of claims 1 to 4.

6. A computer-readable storage medium, characterized in that A readable computer program is stored thereon, and when the program is executed by a processor, the steps of the control method of the dual active bridge converter according to any one of claims 1 to 4 are implemented.

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