Double-BUCK three-port bidirectional conversion circuit based on magnetic coupling and control method

Abstract

The invention relates to a double-BUCK three-port bidirectional conversion circuit based on magnetic coupling and a control method, the double-BUCK three-port bidirectional conversion circuit comprises a first bridge circuit, a second bridge circuit, a voltage transformation circuit, an isolation current conversion network circuit and a controller, the voltage transformation circuit comprises a double-channel magnetic coupling inductor comprising a first coil, a second coil, a common magnetic core and a non-common magnetic core; the first coil and the second coil are in magnetic circuit coupling and act on different branches of the voltage transformation circuit respectively, so that the voltage transformation circuit forms a staggered parallel double-BUCK circuit, external ports of the conversion circuit are DC ports and are used for being connected with a power supply or a load, and the controller controls the conversion circuit to output target voltage and current. The first coil and the second coil share part of the magnetic core, magnetic circuit coupling is formed, the size is effectively reduced, magnetic material loss is reduced, and cost is reduced; according to the invention, the double-channel magnetic coupling inductor is provided to form a staggered parallel double-BUCK circuit, the electric energy conversion efficiency is effectively improved, and current ripples are reduced.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and more specifically, to a magnetic-coupled dual-BUCK three-port bidirectional conversion circuit and a control method thereof. Background Art

[0002] In order to respond to the current demands of energy conservation, emission reduction, and control of air pollution, new energy energy storage systems, new energy engineering vehicles, and electric transportation tools have been greatly promoted and applied in the market. In contrast, the single-channel BUCK circuit used for the DC output port in the prior art has defects such as low conversion efficiency, large output current ripple, and large component losses.

[0003] Therefore, there is an urgent need to develop a magnetic-coupled dual-BUCK three-port bidirectional conversion circuit to improve the problems of low component conversion efficiency, large output current ripple, and large component losses at the third DC port. Summary of the Invention

[0004] The technical problem to be solved by the present invention lies in the problems of low component conversion efficiency, large output current ripple, and large component losses at the DC output port. In view of the above-mentioned defects of the prior art, a magnetic-coupled dual-BUCK three-port bidirectional conversion circuit and a control method thereof are provided.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0006] Construct a magnetic-coupled dual-BUCK three-port bidirectional conversion circuit, which includes a first bridge circuit, a second bridge circuit, a transformer circuit, and an isolated current conversion network circuit. The first bridge circuit, the second bridge circuit, and the transformer circuit are respectively connected to the isolated current conversion network circuit, and the isolated current conversion network circuit is used to provide electrical isolation;

[0007] The transformer circuit includes a dual-channel magnetic-coupled inductor. The dual-channel magnetic-coupled inductor includes a first coil and a second coil, and the first coil and the second coil are magnetically coupled. The first coil and the second coil act on different branches of the transformer circuit respectively, so that the transformer circuit forms two interleaved and parallel BUCK circuits.

[0008] Furthermore, the external ports of the first bridge circuit, the second bridge circuit, and the transformer circuit are all DC ports and are used to connect a power supply or a load.

[0009] Further, the voltage conversion circuit further includes a ninth switch, a tenth switch, an eleventh switch, a twelfth switch, and a fourth capacitor. The ninth switch, the twelfth switch, and the first coil of the dual-channel magnetic coupling inductor form a first BUCK branch. The tenth switch, the eleventh switch, and the second coil of the dual-channel magnetic coupling inductor form a second BUCK branch. The first BUCK branch and the second BUCK branch are interleaved and paralleled, and share the fourth capacitor. The on-off times of the ninth switch and the twelfth switch are opposite. The on-off times of the tenth switch and the eleventh switch are opposite. And the ninth switch and the tenth switch form a phase difference of 0 to 180 degrees in terms of angle.

[0010] Further, the first bridge circuit includes a first switch, a second switch, a third switch, and a fourth switch. The first switch and the third switch form a first bridge arm. The second switch and the fourth switch form a second bridge arm. The first bridge arm and the second bridge arm are connected in parallel with each other. The on-off times of the first switch and the third switch are opposite. The on-off times of the second switch and the fourth switch are opposite.

[0011] Further, the second bridge circuit includes a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a third capacitor. The fifth switch and the seventh switch form a third bridge arm. The sixth switch and the eighth switch form a fourth bridge arm. The third bridge arm, the fourth bridge arm, and the third capacitor are connected in parallel with each other. The on-off times of the fifth switch and the seventh switch are opposite. The on-off times of the sixth switch and the eighth switch are opposite.

[0012] Further, the isolation current conversion network circuit includes a first capacitor, a first inductor, a second capacitor, and a three-winding transformer. The transformer includes a first winding, a second winding, and a third winding. The first capacitor, the first inductor, and the first winding are connected in series. The second capacitor and the second winding are connected in series. The third winding is respectively connected to the ninth switch and the tenth switch. In the isolation current conversion network circuit, the first inductor and the three-winding transformer include the same magnetic core or respectively include different magnetic cores.

[0013] The present invention also provides a device based on a magnetic - coupled dual - BUCK three - port bidirectional conversion circuit, which includes a first bridge module, a second bridge module, a voltage - transformation module, an isolation current - transformation module, and a controller. The isolation current - transformation module is used to connect the first bridge module, the second bridge module, and the voltage - transformation module to form electrical isolation. The external ports of the first bridge module, the second bridge module, and the voltage - transformation module are all DC ports, and the external ports are used to connect a power supply or a load. The controller includes a collection module, an analysis module, and a control module. The analysis module is electrically connected to the collection module and the control module respectively. The controller controls the on - off of each switch in the first bridge module, the second bridge module, and the voltage - transformation module to control the magnitudes of the voltage and current output by the conversion circuit.

[0014] Further, the voltage - transformation module includes a dual - channel magnetic - coupled inductor. The dual - channel magnetic - coupled inductor includes a non - shared magnetic core, coils, and a shared magnetic core. The coils include a first coil and a second coil. A reserved space is provided between the shared magnetic core and the non - shared magnetic core. The first coil and the second coil are located in the reserved space, and the shared magnetic core is located between the first coil and the second coil, so that the first coil and the second coil form magnetic - path coupling.

[0015] The present invention also provides a control method for a magnetic - coupled dual - BUCK three - port bidirectional conversion circuit, including the following steps:

[0016] S1. Collect actual circuit parameters through a preset collection module;

[0017] S2. Analyze the difference between the actual circuit parameters and the preset target circuit parameters through a preset analysis module;

[0018] S3. Control the on - off of multiple preset switches through a preset control module until the actual circuit parameters are equal to the target circuit parameters.

[0019] Further, in the step of controlling the on - off of multiple preset switches through a preset control module until the actual circuit parameters are equal to the target circuit parameters, it further includes:

[0020] Sample the currents on the first coil and the second coil of a preset dual - channel magnetic - coupled inductor respectively through the collection module to obtain sampling results;

[0021] Analyze the sampling results through the analysis module until the currents generated on the first coil and the second coil are in the same value and then superposed to reduce the ripple current and core loss.

[0022] The beneficial effects of the present invention are as follows:

[0023] The present invention relates to a magnetic - coupled dual - BUCK three - port bidirectional conversion circuit and a control method, including a first bridge circuit, a second bridge circuit, a transformer circuit, an isolated current conversion network circuit, and a controller. The transformer circuit includes a dual - channel magnetic - coupled inductor containing a first coil, a second coil, a shared magnetic core, and a non - shared magnetic core. The first coil and the second coil are magnetically coupled, and act on different branches of the transformer circuit respectively, so that the transformer circuit forms an interleaved - parallel dual - BUCK circuit. The external ports of the conversion circuit are all DC ports and are used to connect a power supply or a load. The controller controls the conversion circuit to output a target voltage and current. The present invention proposes that the first coil and the second coil share a part of the magnetic core and form magnetic coupling, effectively reducing the volume, reducing magnetic material loss, and reducing costs. The present invention proposes that the dual - channel magnetic - coupled inductor forms an interleaved - parallel dual - BUCK circuit, effectively improving the power conversion efficiency and reducing the current ripple. Description of the Drawings

[0024] Figure 1 is the circuit diagram of a magnetic - coupled dual - BUCK three - port bidirectional conversion circuit according to an embodiment of the present invention;

[0025] Figure 2 is the control circuit diagram of a magnetic - coupled dual - BUCK three - port bidirectional conversion circuit according to an embodiment of the present invention;

[0026] Figure 3 is the control timing diagram of the controller for each control switch according to an embodiment of the present invention;

[0027] Figure 4 is the voltage simulation waveform diagram of the three - winding transformer when current flows into the first DC port and flows out from the second DC port Vdc2 and the third DC port respectively according to an embodiment of the present invention;

[0028] Figure 5 is the current simulation waveform diagram of the first inductor and the dual - channel magnetic - coupled inductor when current flows into the first DC port and flows out from the second DC port Vdc2 and the third DC port respectively according to an embodiment of the present invention;

[0029] Figure 6 is the current simulation waveform diagram of the first DC port, the second DC port Vdc2, and the third DC port when current flows into the first DC port and flows out from the second DC port Vdc2 and the third DC port respectively according to an embodiment of the present invention;

[0030] Figure 7 is the voltage simulation waveform diagram of the three - winding transformer when current flows into the second DC port Vdc2 and flows out from the first DC port and the third DC port respectively according to an embodiment of the present invention;

[0031] Figure 8It is the current simulation waveform diagram of the first inductor and the dual-channel magnetic coupling inductor when current flows into the second DC port Vdc2 and flows out from the first DC port and the third DC port respectively in an embodiment of the present invention;

[0032] Figure 9 It is the current simulation waveform diagram of the first DC port, the second DC port Vdc2 and the third DC port when current flows into the second DC port Vdc2 and flows out from the first DC port and the third DC port respectively in an embodiment of the present invention;

[0033] Figure 10 It is the voltage simulation waveform diagram of the three-winding transformer when current flows into the third DC port and flows out from the first DC port and the second DC port Vdc2 respectively in an embodiment of the present invention;

[0034] Figure 11 It is the current simulation waveform diagram of the first inductor and the dual-channel magnetic coupling inductor when current flows into the third DC port and flows out from the first DC port and the second DC port Vdc2 respectively in an embodiment of the present invention;

[0035] Figure 12 It is the current simulation waveform diagram of the first DC port, the second DC port Vdc2 and the third DC port when current flows into the third DC port and flows out from the first DC port and the second DC port Vdc2 respectively in an embodiment of the present invention;

[0036] Figure 13 It is the structure diagram of a device of a magnetic coupling dual-BUCK three-port bidirectional conversion circuit in an embodiment of the present invention;

[0037] Figure 14 It is the three-dimensional diagram of the dual-channel magnetic coupling inductor in an embodiment of the present invention;

[0038] Figure 15 It is the exploded view of the dual-channel magnetic coupling inductor in an embodiment of the present invention;

[0039] Figure 16 It is the magnetic simulation diagram of the dual-channel magnetic coupling inductor in an embodiment of the present invention;

[0040] Figure 17 It is the diagram of the current change of the first coil and the second coil of the dual-channel magnetic coupling inductor with time under the target parameters in an embodiment of the present invention;

[0041] Figure 18 It is the diagram of the current change of the third DC port with time under the target parameters in an embodiment of the present invention;

[0042] Figure 19 It is the flowchart of a control method of a magnetic coupling dual-BUCK three-port bidirectional conversion circuit in an embodiment of the present invention.

[0043] Description of reference numerals:

[0044] Q1, the first switch; Q2, the second switch; Q3, the third switch; Q4, the fourth switch; L1, the first inductor; C1, the first capacitor; Q5, the fifth switch; Q6, the sixth switch; Q7, the seventh switch; Q8, the eighth switch; C2, the second capacitor; C3, the third capacitor; L2, the dual - channel magnetic - coupled inductor; L2_W1, the first coil; L2_W2, the second coil; Q9, the ninth switch; Q10, the tenth switch; Q11, the eleventh switch; Q12, the twelfth switch; C4, the fourth capacitor; T1, the three - winding transformer; T1_W1, the first winding; T1_W2, the second winding; T1_W3, the third winding; Vdc1, the first DC port; Vdc2, the second DC port Vdc2; Vdc3, the third DC port; 10, the first bridge module; 20, the second bridge module; 30, the transformer module; 40, the controller; 401, the acquisition module; 402, the analysis module; 403, the control module; 50, the isolation current conversion module; 1, the common magnetic core; 2, the non - common magnetic core. Detailed implementation manners

[0045] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0046] Please refer to the attached Figures 1 - 19 , the present invention provides a magnetic - coupled dual - BUCK three - port bidirectional conversion circuit, including a first bridge circuit, a second bridge circuit, a transformer circuit and an isolation current conversion network circuit. The first bridge circuit, the second bridge circuit and the transformer circuit are respectively connected to the isolation current conversion network circuit, and the isolation current conversion network circuit is used to provide electrical isolation;

[0047] The transformer circuit includes a dual - channel magnetic - coupled inductor L2. The dual - channel magnetic - coupled inductor L2 includes a first coil L2_W1 and a second coil L2_W2, and the first coil L2_W1 and the second coil L2_W2 are magnetically coupled; the first coil L2_W1 and the second coil L2_W2 act on different branches of the transformer circuit respectively, so that the transformer circuit forms two interleaved and parallel BUCK circuits.

[0048] In this embodiment, the external ports of the first bridge circuit, the second bridge circuit, and the transformer circuit are all DC ports and are used to connect to a power supply or a load. Among them, any one of the external ports is randomly selected to connect to the power supply, and the remaining two external ports are connected to the load to form a three-port bidirectional output circuit. In a specific embodiment, the case where the external port of the first bridge circuit is connected to the power supply and the other external ports are connected to the load is mainly discussed; the first bridge circuit includes a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4. The first switch Q1 and the third switch Q3 form a first bridge arm, and the second switch Q2 and the fourth switch Q4 form a second bridge arm. The first bridge arm and the second bridge arm are connected in parallel with each other. The on-off times of the first switch Q1 and the third switch Q3 are opposite, and the on-off times of the second switch Q2 and the fourth switch Q4 are opposite. By controlling the on-off times of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4, the magnitude and direction of the voltage and current flowing into the second bridge circuit and the transformer circuit are controlled; the second bridge circuit includes a fifth switch Q5, a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, and a third capacitor C3. The fifth switch Q5 and the seventh switch Q7 form a third bridge arm, and the sixth switch Q6 and the eighth switch Q8 form a fourth bridge arm. The third bridge arm, the fourth bridge arm, and the third capacitor C3 are connected in parallel with each other. The on-off times of the fifth switch Q5 and the seventh switch Q7 are opposite, and the on-off times of the sixth switch Q6 and the eighth switch Q8 are opposite. By controlling the on-off times of the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, and the eighth switch Q8, the magnitude and direction of the voltage and current output from the external port of the second bridge circuit are controlled; the transformer circuit includes a dual-channel magnetic coupling inductor L2, a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11, a twelfth switch Q12, and a fourth capacitor C4. The dual-channel magnetic coupling inductor L2 includes a first coil L2_W1, a second coil L2_W2, a common magnetic core 1, and a non-common magnetic core 2, and the first coil L2_W1 and the second coil L2_W2 form a magnetic circuit coupling through the common magnetic core 1; the ninth switch Q9, the twelfth switch Q12, and the first coil L2_W1 of the dual-channel magnetic coupling inductor L2 form a first BUCK branch, and the tenth switch Q10, the eleventh switch Q11, and the second coil L2_W2 of the dual-channel magnetic coupling inductor L2 form a second BUCK branch. The first BUCK branch and the second BUCK branch share the fourth capacitor C4 and form two interleaved parallel BUCK branches. The on-off times of the ninth switch Q9 and the twelfth switch Q12 are opposite, and the on-off times of the tenth switch Q10 and the eleventh switch Q11 are opposite. Moreover, the ninth switch Q9 and the tenth switch Q10 form a phase difference of 0 to 180 degrees. By controlling the on-off times of the ninth switch Q9, the tenth switch Q10, the eleventh switch Q11, and the twelfth switch Q12, the magnitude and direction of the voltage and current output from the external port of the transformer circuit are controlled;The first bridge circuit, the second bridge circuit, and the transformer circuit are respectively connected to the isolation current conversion network circuit. The isolation current conversion network circuit includes a first capacitor C1, a first inductor L1, a second capacitor C2, and a three-winding transformer T1. The transformer includes a first winding T1_W1, a second winding T1_W2, and a third winding T1_W3. The first capacitor C1, the first inductor L1, and the first winding T1_W1 are connected in series and are respectively connected to the first bridge arm and the second bridge arm. The second capacitor C2 and the second winding T1_W2 are connected in series and are respectively connected to the third bridge arm and the fourth bridge arm. The third winding T1_W3 is respectively connected to the ninth switch Q9 and the tenth switch Q10. The isolation current conversion network circuit is used to provide electrical isolation. In the isolation current conversion network circuit, the first inductor L1 and the three-winding transformer T1 include the same magnetic core or respectively include different magnetic cores; in a specific embodiment, the switches included in the conversion circuit can be switches such as SiC (silicon carbide), GaN (gallium nitride), IGBT (Insulated-Gate Bipolar Transistor), MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor); the first inductor L1 is a resonant inductor for storing and transmitting energy; both the first capacitor C1 and the second capacitor C2 are DC-blocking capacitors for blocking DC signals and allowing AC signals to pass through.

[0049] The present invention proposes that the first coil L2_W1 and the second coil L2_W2 of the dual-channel magnetically coupled inductor L2 share a part of the magnetic core and form a magnetic circuit coupling, effectively reducing the volume of the device, reducing the magnetic material loss, and reducing the cost; the present invention proposes that the dual-channel magnetically coupled inductor L2 acts on different branches of the transformer circuit to form two interleaved parallel BUCK circuits, effectively improving the power conversion efficiency and effectively reducing the current ripple at the external ports of the transformer circuit; the circuit of the present invention has a high degree of integration. In the case of having functions such as battery charging management, battery discharging management, and pre-charging of the circuit loop, the types and quantities of components used are small, not only reducing the volume of the current converter, reducing the weight, but also effectively reducing the cost of the power electronic current converter, improving the power conversion efficiency, and achieving the social benefits of energy conservation and emission reduction.

[0050] Please refer to Figure 1 and Figure 12 , the external ports of the first bridge circuit, the second bridge circuit, and the transformer circuit are all DC ports and are used to connect to a power source or a load.

[0051] In specific implementation: The external ports of the first bridge circuit, the second bridge circuit, and the transformer circuit are all DC ports and are used to connect to a power source or a load. Among them, any one of the external ports is selected to connect to the power source, and the remaining two external ports are used to connect to the load, forming a three-port bidirectional dual-port output circuit. In a specific embodiment, the external port of the first bridge circuit is the first DC port Vdc1, the external port of the second bridge circuit is the second DC port Vdc2, and the external port of the transformer circuit is the third DC port Vdc3; there are three cases for the input and output of the external ports. In the first case, when the first DC port Vdc1 of the first bridge circuit is connected to the power source, the second DC port Vdc2 of the second bridge circuit and the third DC port Vdc3 of the transformer circuit can be connected to the load, and the current flows in from the first DC port Vdc1 and flows out from the second DC port Vdc2 and the third DC port Vdc3 respectively; in the second case, when the second DC port Vdc2 of the second bridge circuit is connected to the power source, the first DC port Vdc1 of the first bridge circuit and the third DC port Vdc3 of the transformer circuit can be connected to the load, and the current flows in from the second DC port Vdc2 and flows out from the first DC port Vdc1 and the third DC port Vdc3 respectively; in the third case, when the third DC port Vdc3 of the transformer circuit is connected to the power source, the first DC port Vdc1 of the first bridge circuit and the second DC port Vdc2 of the second bridge circuit can be connected to the load, and the current flows in from the third DC port Vdc3 and flows out from the first DC port Vdc1 and the second DC port Vdc2 respectively; realizing bidirectional dual-port output, and having functions such as battery charging management, battery discharging management, and pre-charging of the circuit loop; the present invention mainly discusses the first case. In a specific embodiment, the first case can be specifically applied to a new energy vehicle. The first DC port Vdc1 is connected to the mains power to input electrical energy to the conversion circuit, the second DC port Vdc2 is used to charge the power battery of the new energy vehicle, and the third DC port Vdc3 is used to supply power to the low-voltage devices on the vehicle.

[0052] More specifically, Figure 4 、 Figure 5 and Figure 6 are simulation diagrams obtained when the current flows in from the first DC port Vdc1 and the current flows out from the second DC port Vdc2 and the third DC port Vdc3 respectively. Figure 4 respectively include the voltage-time transformation curve diagrams of the first winding T1_W1 end, the second winding T1_W2 end, and the third winding T1_W3 end of the three-winding transformer T1. Figure 5 is the current-time variation diagram of the first inductor L1 and the dual-channel magnetically coupled inductor L2. Figure 6 is the current-time variation diagram of the first DC port Vdc1, the second DC port Vdc2, and the third DC port Vdc3. Figure 7 、 Figure 8 andFigure 9 The simulation waveforms obtained when current flows into the second DC port Vdc2 and flows out of the first DC port Vdc1 and the third DC port Vdc3 respectively. Figure 10 、 Figure 11 and Figure 12 are the simulation waveforms obtained when current flows into the third DC port Vdc3 and flows out of the first DC port Vdc1 and the second DC port Vdc2 respectively; in a specific embodiment, the dual-channel magnetic coupling inductor L2 includes a first coil L2_W1 and a second coil L2_W2, and the coil pins have no fixed polarity direction. Therefore, the two current transformation curves need to be determined according to the specific connection mode of the coils; the first-port transformer voltage refers to the voltage at the first winding T1_W1 end of the transformer, the second-port transformer voltage refers to the voltage at the second winding T1_W2 end of the transformer, and the third-port transformer voltage refers to the voltage at the third winding T1_W3 end of the transformer.

[0053] Please refer to Figure 1 , the first bridge circuit, the second bridge circuit and the transformer circuit are respectively connected to the isolated current transformation network circuit. The isolated current transformation network circuit includes a first capacitor C1, a first inductor L1, a second capacitor C2 and a three-winding transformer T1. The transformer includes a first winding T1_W1, a second winding T1_W2 and a third winding T1_W3. The first capacitor C1, the first inductor L1 and the first winding T1_W1 are connected in series and are respectively connected to the first bridge arm and the second bridge arm. The second capacitor C2 and the second winding T1_W2 are connected in series and are respectively connected to the third bridge arm and the fourth bridge arm. The third winding T1_W3 is respectively connected to the ninth switch Q9 and the tenth switch Q10. The isolated current transformation network circuit is used to provide electrical isolation; in the isolated current transformation network circuit, the first inductor L1 and the three-winding transformer T1 include the same magnetic core or respectively include different magnetic cores.

[0054] In specific implementation: The first bridge circuit, the second bridge circuit, and the transformer circuit are respectively connected to the isolation current conversion network circuit. The isolation current conversion network circuit includes a first capacitor C1, a first inductor L1, a second capacitor C2, and a three-winding transformer T1. The transformer includes a first winding T1_W1, a second winding T1_W2, and a third winding T1_W3. The first capacitor C1, the first inductor L1, and the first winding T1_W1 are connected in series, and one end is connected between the first switch Q1 and the third switch Q3, and the other end is connected between the second switch Q2 and the fourth switch Q4. The second capacitor C2 and the second winding T1_W2 are connected in series, and one end is connected between the fifth switch Q5 and the seventh switch Q7, and the other end is connected between the sixth switch Q6 and the eighth switch Q8. The third winding T1_W3 is respectively connected to the ninth switch Q9 and the tenth switch Q10. The isolation current conversion network circuit is used to provide electrical isolation. In the isolation current conversion network circuit, when the first inductor L1 and the three-winding transformer T1 are respectively wound with different magnetic cores, at this time, the first inductor L1 and the three-winding transformer T1 are connected in series in a non-magnetic coupling form; when the first inductor L1 and the three-winding transformer T1 are wound with the same magnetic core, at this time, the inductive magnetic flux of the first inductor L1 is generated by the leakage inductance between the first winding T1_W1 and the second winding T1_W2 in the three-winding transformer T1, that is, the first inductor L1 and the three-winding transformer T1 are connected in series in a magnetic coupling form. In a specific embodiment, the series order of the first capacitor C1, the first inductor L1, and the first winding T1_W1 is not fixed, and the series order of the second capacitor C2 and the second winding T1_W2 is not fixed.

[0055] Please refer to Figures 1 - 3 , the first bridge circuit includes a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4. The first switch Q1 and the third switch Q3 form a first bridge arm, the second switch Q2 and the fourth switch Q4 form a second bridge arm, the first bridge arm and the second bridge arm are connected in parallel to each other. The on-off times of the first switch Q1 and the third switch Q3 are opposite, and the on-off times of the second switch Q2 and the fourth switch Q4 are opposite. By controlling the on-off times of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4, the magnitudes and directions of the voltage and current flowing into the second bridge circuit and the transformer circuit are controlled.

[0056] In specific implementation: The first bridge circuit includes a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4. The first switch Q1 and the third switch Q3 form a first arm, and the second switch Q2 and the fourth switch Q4 form a second arm. The first arm and the second arm are connected in parallel to the first DC port Vdc1. The on-off times of the first switch Q1 and the third switch Q3 are opposite to each other, and the on-off times of the second switch Q2 and the fourth switch Q4 are opposite to each other. The on-off times of the first switch Q1 and the fourth switch Q4 are the same, and the on-off times of the second switch Q2 and the third switch Q3 are the same. By controlling the on-off times of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4, the magnitudes and directions of the voltage and current flowing into the second bridge circuit and the transformer circuit are controlled. In a specific embodiment, the on-off times of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 determine the magnitude and direction of the current and voltage in the first winding T1_W1. There is coupling between the first winding T1_W1, the second winding T1_W2, and the third winding T1_W3, thereby determining the magnitudes and directions of the current and voltage in the second winding T1_W2 and the third winding T1_W3, that is, the magnitudes and directions of the voltage and current flowing into the second bridge circuit and the transformer circuit are controlled.

[0057] Please refer to Figures 1 - 3 , The second bridge circuit includes a fifth switch Q5, a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, and a third capacitor C3. The fifth switch Q5 and the seventh switch Q7 form a third arm, and the sixth switch Q6 and the eighth switch Q8 form a fourth arm. The third arm, the fourth arm, and the third capacitor C3 are connected in parallel. The on-off times of the fifth switch Q5 and the seventh switch Q7 are opposite to each other, and the on-off times of the sixth switch Q6 and the eighth switch Q8 are opposite to each other. By controlling the on-off times of the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, and the eighth switch Q8, the magnitudes and directions of the output voltage and current of the external port of the second bridge circuit are controlled.

[0058] In specific implementation: The second bridge circuit includes a fifth switch Q5, a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, and a third capacitor C3. The fifth switch Q5 and the seventh switch Q7 form a third bridge arm, the sixth switch Q6 and the seventh switch Q7 form a fourth bridge arm. The third bridge arm, the fourth bridge arm, and the third capacitor C3 are mutually connected in parallel to the second DC port Vdc2. The on-off times of the fifth switch Q5 and the seventh switch Q7 are opposite, the on-off times of the sixth switch Q6 and the eighth switch Q8 are opposite, the on-off times of the fifth switch Q5 and the eighth switch Q8 are the same, and the on-off times of the sixth switch Q6 and the seventh switch Q7 are the same. By controlling the on-off times of the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, and the eighth switch Q8, the control of the magnitude and direction of the output voltage and current of the external port of the second bridge circuit is realized. In a specific embodiment, when charging the load of the second DC port Vdc2, according to the magnitude and direction of the voltage and current on the second winding T1_W2, by controlling the on-off times of the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, and the eighth switch Q8, the control of the magnitude and direction of the output voltage and current of the external port of the second bridge circuit can be realized.

[0059] Please refer to Figures 1 - 18 , the voltage transformation circuit includes a dual-channel magnetic coupling inductor L2, a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11, a twelfth switch Q12, and a fourth capacitor C4. The dual-channel magnetic coupling inductor L2 includes a first coil L2_W1, a second coil L2_W2, a shared magnetic core 1, and a non-shared magnetic core 2, and the first coil L2_W1 and the second coil L2_W2 form a magnetic path coupling through the shared magnetic core 1; the ninth switch Q9, the twelfth switch Q12, and the first coil L2_W1 of the dual-channel magnetic coupling inductor L2 form a first BUCK branch, the tenth switch Q10, the eleventh switch Q11, and the second coil L2_W2 of the dual-channel magnetic coupling inductor L2 form a second BUCK branch. The first BUCK branch and the second BUCK branch share the fourth capacitor C4 and form two interleaved and parallel BUCK branches. The on-off times of the ninth switch Q9 and the twelfth switch Q12 are opposite, the on-off times of the tenth switch Q10 and the eleventh switch Q11 are opposite, and a phase difference of 0 to 180 degrees is formed between the ninth switch Q9 and the tenth switch Q10. By controlling the on-off times of the ninth switch Q9, the tenth switch Q10, the eleventh switch Q11, and the twelfth switch Q12, the control of the magnitude and direction of the output voltage and current of the external port of the voltage transformation circuit is realized.

[0060] In specific implementation: The voltage conversion circuit includes a dual-channel magnetic coupling inductor L2. The dual-channel magnetic coupling inductor L2 includes a first coil L2_W1, a second coil L2_W2, and a common magnetic core 1. The common magnetic core 1 is located between the first coil L2_W1 and the second coil L2_W2, and the first coil L2_W1 is magnetically coupled to the second coil L2_W2 through the common magnetic core 1. The first coil L2_W1 and the second coil L2_W2 act on different branches of the voltage conversion circuit respectively, so that the voltage conversion circuit forms a dual-BUCK circuit with interleaved parallel connection. Among them, the DC-DC BUCK circuit is a buck chopper circuit, which realizes the buck conversion from DC to DC; the voltage conversion circuit also includes a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11, a twelfth switch Q12, and a fourth capacitor C4. The ninth switch Q9, the twelfth switch Q12, and the first coil L2_W1 of the dual-channel magnetic coupling inductor L2 form a first BUCK branch, and the tenth switch Q10, the eleventh switch Q11, and the second coil L2_W2 of the dual-channel magnetic coupling inductor L2 form a second BUCK branch. The first BUCK branch and the second BUCK branch share the fourth capacitor C4 and form two interleaved parallel BUCK branches. The on-off times of the ninth switch Q9 and the twelfth switch Q12 are opposite, the on-off times of the tenth switch Q10 and the eleventh switch Q11 are opposite, and a phase difference of 0 to 180 degrees is formed between the ninth switch Q9 and the tenth switch Q10. By controlling the on-off times of the ninth switch Q9, the tenth switch Q10, the eleventh switch Q11, and the twelfth switch Q12, the magnitude and direction of the output voltage and current of the external port of the voltage conversion circuit can be controlled. Among them, as Figure 17 shown, there is a certain phase difference between the currents of the first coil L2_W1 and the second coil L2_W2 of the dual-channel magnetic coupling inductor L2. As Figure 18 shown, after the currents of the first coil L2_W1 and the second coil L2_W2 are superimposed, a direct current is output at the third DC port Vdc3 to reduce the ripple current and core loss; in a specific embodiment, according to the magnitude and direction of the voltage and current on the third winding T1_W3, by controlling the on-off times of the ninth switch Q9, the tenth switch Q10, the eleventh switch Q11, and the twelfth switch Q12, the magnitude and direction of the output voltage and current of the external port of the voltage conversion circuit can be realized; the dual-BUCK circuit with interleaved parallel connection realizes the buck conversion from DC to DC, effectively improving the conversion efficiency of the third DC port Vdc3 and effectively reducing the ripple of the output current.

[0061] Please refer to Figure 2 and Figure 16, a device based on a magnetic - coupled dual - BUCK three - port bidirectional conversion circuit, includes a first bridge module 10, a second bridge module 20, a transformer module 30, an isolation current conversion module 50, and a controller 40. The isolation current conversion module 50 is used to connect the first bridge module 10, the second bridge module 20, and the transformer module 30 to form electrical isolation. The external ports of the first bridge module 10, the second bridge module 20, and the transformer module 30 are all DC ports and are used to connect a power supply or a load. The controller 40 includes a collection module 401, an analysis module 402, and a control module 403, and is used to control the on - off of each switch in the first bridge module 10, the second bridge module 20, and the transformer module 30 to control the magnitudes of the output voltage and current of the external ports. The transformer module 30 includes a dual - channel magnetic - coupled inductor L2. The dual - channel magnetic - coupled inductor L2 includes a non - shared magnetic core 2, coils, a shared magnetic core 1, and coils. The coils include a first coil L2_W1 and a second coil L2_W2. There is a reserved space between the shared magnetic core 1 and the non - shared magnetic core 2. The first coil L2_W1 and the second coil L2_W2 are located in the reserved space, and the shared magnetic core 1 is located between the first coil L2_W1 and the second coil L2_W2, so that the first coil L2_W1 and the second coil L2_W2 form a magnetic - path coupling.

[0062] In specific implementation: The transformer module 30 includes a dual - channel magnetic - coupled inductor L2. The dual - channel magnetic - coupled inductor L2 includes a non - shared magnetic core 2, coils, and a shared magnetic core 1. The coils include a first coil L2_W1 and a second coil L2_W2. There is a reserved space between the shared magnetic core 1 and the non - shared magnetic core 2. The first coil L2_W1 and the second coil L2_W2 are located in the reserved space, and the shared magnetic core 1 is located between the first coil L2_W1 and the second coil L2_W2, so that the first coil L2_W1 and the second coil L2_W2 form a magnetic - path coupling, effectively reducing the volume of the device, reducing the magnetic material loss, and reducing the cost.

[0063] More specifically, please refer to Figure 16 , Figure 16 is the magnetic simulation diagram of the dual - channel magnetic - coupled inductor L2. When current flows into the dual - channel magnetic - coupled inductor L2, the dual - channel magnetic - coupled inductor L2 converts electrical energy into magnetic energy for storage. In the figure, red represents a very high magnetic - flux density, and the redder it is, the higher the magnetic - flux density, the greater the loss, and the more serious the heating; green represents a medium - level magnetic - flux density, with less loss and less heating; blue represents a very small magnetic - flux density, even zero. It can be seen from the simulation diagram that a large area of the shared magnetic core 1 of the two inductors is green, and even blue areas appear, indicating that after the magnetic fields of the shared magnetic paths are superimposed and canceled each other, the magnetic material loss is greatly reduced, the conversion efficiency is improved, and the heating of the inductor is reduced.

[0064] Please refer to the appendix Figures 1 - 19, in an embodiment of the present invention, a control method for a magnetic coupling dual-BUCK three-port bidirectional conversion circuit includes the following steps:

[0065] S1. Collect actual circuit parameters through a preset acquisition module 401;

[0066] S2. Analyze the difference between the actual circuit parameters and the target circuit parameters through a preset analysis module 402;

[0067] S3. Control the on / off of each switch through a preset control module 403 until the actual circuit parameters are equal to the target circuit parameters.

[0068] Among them, in the step of controlling the on / off of a plurality of preset switches through a preset control module 403 until the actual circuit parameters are equal to the target circuit parameters, it further includes:

[0069] Sample the currents on the first coil L2_W1 and the second coil L2_W2 of the preset dual-channel magnetic coupling inductor L2 respectively through the acquisition module 401 to obtain sampling results;

[0070] Analyze the sampling results through the analysis module 402 until the currents generated on the first coil L2_W1 and the second coil L2_W2 are superimposed after reaching the same value to reduce the ripple current and core loss.

[0071] In the above steps, first collect the actual circuit parameters through a preset acquisition module 401. In a specific embodiment, first electrically connect the controller 40 to the first bridge circuit, the second bridge circuit, and the transformer circuit. The acquisition module 401 of the controller 40 collects the actual circuit parameters in the circuit. The actual circuit parameters mainly include the current of the dual-channel magnetic coupling inductor L2 and the current of the third DC port Vdc3. In a specific embodiment, sample the currents on the first coil L2_W1 and the second coil L2_W2 of the preset dual-channel magnetic coupling inductor L2 respectively through the acquisition module 401 to obtain sampling results; then analyze the difference between the actual circuit parameters and the target circuit parameters through a preset analysis module 402. In a specific embodiment, the ripple of the output current of the third DC port Vdc3 in the target circuit parameters should be small enough; finally, control the on / off of each switch through a preset control module 403 until the actual circuit parameters are equal to the target circuit parameters. In a specific embodiment, the control timing diagram of the control module 403 for each switch is as Figure 3 , analyze the sampling results through the analysis module 402. There is a certain phase difference between the currents of the first coil L2_W1 and the second coil L2_W2 of the dual-channel magnetic coupling inductor L2, as Figure 17 shown, until the currents of the first coil L2_W1 and the second coil L2_W2 are superimposed after reaching the same value to reduce the ripple current and core loss, as Figure 18as shown

[0072] It should be noted that in this text, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent in such a process, device, article or method. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, device, article or method including that element.

[0073] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A three-port bidirectional conversion circuit based on magnetic coupling double BUCK, characterized in that: It includes a first bridge circuit, a second bridge circuit, a voltage conversion circuit and an isolated current conversion network circuit, wherein the first bridge circuit, the second bridge circuit and the voltage conversion circuit are respectively connected to the isolated current conversion network circuit, and the isolated current conversion network circuit is used to provide electrical isolation; The voltage conversion circuit includes a dual-channel magnetically coupled inductor, which includes a first coil and a second coil, and the first coil is magnetically coupled to the second coil; the first coil and the second coil act on different branches of the voltage conversion circuit respectively, so that the voltage conversion circuit forms two BUCK circuits that are staggered in parallel.

2. The magnetically coupled dual-BUCK three-port bidirectional conversion circuit according to claim 1 is characterized in that: The external ports of the first bridge circuit, the second bridge circuit and the transformer circuit are all DC ports and are used to connect a power source or a load.

3. The magnetically coupled dual-BUCK three-port bidirectional conversion circuit according to claim 1 is characterized in that: The voltage conversion circuit further includes a ninth switch, a tenth switch, an eleventh switch, a twelfth switch and a fourth capacitor, the ninth switch, the twelfth switch and the first coil of the dual-channel magnetic coupling inductor form a first BUCK branch, the tenth switch, the eleventh switch and the second coil of the dual-channel magnetic coupling inductor form a second BUCK branch, the first BUCK branch and the second BUCK branch are alternately connected in parallel and share the fourth capacitor; The on-off time of the ninth switch is opposite to that of the twelfth switch, the on-off time of the tenth switch is opposite to that of the eleventh switch, and the ninth switch and the tenth switch form an angular phase difference of 0 to 180 degrees.

4. The magnetically coupled dual-BUCK three-port bidirectional conversion circuit according to claim 1 is characterized in that: The first bridge circuit includes a first switch, a second switch, a third switch and a fourth switch, the first switch and the third switch form a first bridge arm, the second switch and the fourth switch form a second bridge arm, the first bridge arm and the second bridge arm are connected in parallel to each other, the on-off time of the first switch is opposite to that of the third switch, and the on-off time of the second switch is opposite to that of the fourth switch.

5. The magnetically coupled dual-BUCK three-port bidirectional conversion circuit according to claim 1 is characterized in that: The second bridge circuit includes a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a third capacitor. The fifth switch and the seventh switch form a third bridge arm, the sixth switch and the eighth switch form a fourth bridge arm, the third bridge arm, the fourth bridge arm, and the third capacitor are connected in parallel to each other, the on-off time of the fifth switch and the seventh switch are opposite, and the on-off time of the sixth switch and the eighth switch are opposite.

6. The magnetically coupled dual-BUCK three-port bidirectional conversion circuit according to claim 3 is characterized in that: The isolated current conversion network circuit includes a first capacitor, a first inductor, a second capacitor and a three-winding transformer, the transformer includes a first winding, a second winding and a third winding, the first capacitor, the first inductor and the first winding are connected in series, the second capacitor and the second winding are connected in series, and the third winding is connected to the ninth switch and the tenth switch respectively; In the isolated current conversion network circuit, the first inductor and the three-winding transformer include the same magnetic core or different magnetic cores.

7. A device based on a magnetically coupled dual-BUCK three-port bidirectional conversion circuit, characterized in that: It includes a first bridge module, a second bridge module, a transformer module, an isolated current conversion module and a controller. The isolated current conversion module is used to connect the first bridge module, the second bridge module and the transformer module to form electrical isolation. The external ports of the first bridge module, the second bridge module and the transformer module are all DC ports, and the external ports are used to connect a power supply or a load. The controller includes an acquisition module, an analysis module and a control module. The analysis module is electrically connected to the acquisition module and the control module respectively. The controller controls the on and off of each switch in the first bridge module, the second bridge module and the transformer module to control the voltage and current output by the change circuit.

8. The device based on the magnetically coupled dual-BUCK three-port bidirectional conversion circuit according to claim 7 is characterized in that: The transformer module includes a dual-channel magnetically coupled inductor, which includes a non-shared magnetic core, a coil and a shared magnetic core. The coil includes a first coil and a second coil. A reserved space is provided between the shared magnetic core and the non-shared magnetic core. The first coil and the second coil are located in the reserved space. The shared magnetic core is located between the first coil and the second coil, so that the first coil and the second coil form a magnetic circuit coupling.

9. A control method based on a magnetically coupled dual-BUCK three-port bidirectional conversion circuit, characterized in that: The following steps are involved: S1. Collecting actual circuit parameters through a preset collection module; S2. Analyzing the difference between the actual circuit parameter and the preset target circuit parameter by a preset analysis module; S3. Controlling the on and off of a plurality of preset switches through a preset control module until the actual circuit parameter is equal to the target circuit parameter.

10. The control method based on the magnetically coupled dual-BUCK three-port bidirectional conversion circuit according to claim 9 is characterized in that: The step of controlling the on and off of a plurality of preset switches by a preset control module until the actual circuit parameter is equal to the target circuit parameter further includes: The current on the first coil and the second coil of the preset dual-channel magnetic coupling inductor are sampled and processed respectively by the acquisition module to obtain a sampling result; The sampling result is analyzed by the analysis module until the currents generated on the first coil and the second coil are at the same value and then superimposed to reduce ripple current and core loss.

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