Conversion circuit based on magnetic coupling double BUCK and single-stage isolation PFC and control method

Abstract

The invention relates to a conversion circuit based on magnetic coupling double BUCK and single-stage isolation PFC and a control method, the conversion circuit comprises a rectification circuit, a transformation circuit and a controller, external ports comprise an AC port and a plurality of DC ports and are used for connecting a power supply or a load, the rectification circuit comprises a first adjusting circuit, a second adjusting circuit and an isolation circuit, and the first adjusting circuit is connected with the controller. The isolation circuit is used for forming electrical isolation, the transformation circuit comprises a dual-channel magnetic coupling inductor formed by magnetic circuit coupling of a first coil and a second coil, so that the transformation circuit forms a staggered parallel dual-BUCK circuit, and the controller controls the transformation circuit to output target voltage and current. The dual-channel magnetic coupling inductors are adopted to form two BUCK circuits, the voltage and current conversion efficiency is effectively improved, magnetic material loss is reduced, and the cost is reduced; the single-stage isolation PFC rectification circuit and the double-BUCK DCDC circuit are combined to form a three-port bidirectional conversion circuit, power is directly supplied through commercial power, and charging and discharging management of a direct current output port is achieved.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and more particularly, to a conversion circuit and a control method based on magnetic coupling dual-BUCK and single-stage isolated PFC. Background Art

[0002] With the increasing demands for 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, many existing technologies achieve battery charge and discharge management or load power supply through two-stage circuit conversion, that is, first rectify the mains alternating current through a PFC circuit, and then use an isolated DCDC conversion circuit to adjust the voltage and current, or use a single-channel BUCK circuit to manage the battery charge and discharge of the second DC port or supply power to the load, which has the defects of large output current ripple, large component losses, large volume, high cost, and low conversion efficiency.

[0003] Therefore, there is an urgent need in the industry to develop a conversion circuit based on magnetic coupling dual-BUCK and single-stage isolated PFC, which has both PFC rectification function and the function of isolating and adjusting voltage and current, so as to improve the problems of large output current ripple, large component losses, large volume, high cost, and low conversion efficiency brought by traditional technologies. Summary of the Invention

[0004] The technical problem to be solved by the present invention is large output current ripple, large component losses, large volume, high cost, and low conversion efficiency. In view of the above defects of the prior art, a conversion circuit and a control method based on magnetic coupling dual-BUCK and single-stage isolated PFC are provided.

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

[0006] Construct a conversion circuit based on magnetic coupling dual-BUCK and single-stage isolated PFC, which includes a rectification circuit and a voltage conversion circuit. An isolation circuit is provided in the rectification circuit, and the isolation circuit is used to provide electrical isolation so that the rectification circuit forms a single-stage isolated PFC circuit;

[0007] The voltage conversion circuit includes a plurality of coils, and the coils are magnetically coupled to each other. The coils are located on the second inductor of the voltage conversion circuit so that the second inductor forms a multi-channel magnetically coupled inductor. The coils act on different branches of the voltage conversion circuit respectively to form a plurality of BUCK circuits;

[0008] The voltage conversion circuit is electrically connected to the rectification circuit through the isolation circuit;

[0009] The external ports of the rectifying circuit and the voltage transforming circuit include an AC port and multiple DC ports, and the external ports are used to connect to a power source or a load.

[0010] Further, the rectifying circuit further includes a first regulating circuit and a second regulating circuit, and the first regulating circuit and the second regulating circuit are connected through the isolation circuit.

[0011] Further, the isolation circuit includes a first capacitor, a first inductor, a second capacitor, and a three-winding transformer. The three-winding 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 and connected to the first regulating circuit. The second capacitor and the second winding are connected in series and connected to the second regulating circuit. The third winding is connected to the voltage transforming circuit;

[0012] In the isolation circuit, the first inductor and the three-winding transformer include the same magnetic core or respectively include different magnetic cores.

[0013] Further, the first regulating circuit includes multiple switch groups, and any one of the switch groups includes multiple switching tubes. The switching tubes are arranged in combination so that the switch group can be controlled bidirectionally.

[0014] Further, the first regulating circuit includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a primary capacitor. The first switch and the second switch form a first switch group. The third switch and the fourth switch form a second switch group. The fifth switch and the sixth switch form a third switch group. The seventh switch and the eighth switch form a fourth switch group. The first switch group and the third switch group constitute a first bridge arm. The second switch group and the fourth switch group constitute a second bridge arm. The primary capacitor, the first bridge arm, and the second bridge arm are connected in parallel with each other;

[0015] The on-off time in the switch group corresponds to the positive and negative cycles of the input waveform of the AC port.

[0016] Further, the second regulating circuit includes a ninth switch, a tenth switch, an eleventh switch, a twelfth switch, and a third capacitor. The ninth switch and the eleventh switch constitute a third bridge arm. The tenth switch and the twelfth switch constitute 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 ninth switch and the eleventh switch are opposite. The on-off times of the tenth switch and the twelfth switch are opposite.

[0017] Further, the coil includes a first coil and a second coil; the voltage conversion circuit further includes a thirteenth switch, a fourteenth switch, a fifteenth switch, a sixteenth switch, and a fourth capacitor. The thirteenth switch, the fifteenth switch, and the first coil of the multi-channel magnetic coupling inductor form a first BUCK branch. The fourteenth switch, the sixteenth switch, and the second coil of the multi-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.

[0018] There is a region where the on-off times of the thirteenth switch and the fifteenth switch are opposite to each other in part, and there is a region where the on-off times of the fourteenth switch and the sixteenth switch are opposite to each other in part. Moreover, the thirteenth switch and the fourteenth switch form a phase difference of 0 to 180 degrees.

[0019] The present invention also provides a device based on a magnetic coupling dual-BUCK and single-stage isolated PFC conversion circuit, including a rectification module, a voltage conversion module, and a controller. The rectification module includes a first adjustment module, a second adjustment module, and an isolation module. The isolation module is used to connect the first adjustment module, the second adjustment module, and the voltage conversion module to form electrical isolation. The external ports of the first adjustment module, the second adjustment module, and the voltage conversion module include an AC port and multiple DC ports, and the external ports are used to connect to a power supply or a load.

[0020] The voltage conversion module includes a multi-channel magnetic coupling inductor. The multi-channel magnetic coupling inductor includes a first coil, a second coil, a non-shared magnetic core, and a shared magnetic core. The non-shared magnetic cores are respectively located outside the first coil and the second coil and tightly surround the first coil and the second coil. The shared magnetic core is located between the first coil and the second coil to enable magnetic circuit coupling between the first coil and the second coil.

[0021] The controller includes a collection module, an analysis module, a judgment module, and a control module. The analysis module and the judgment module are electrically connected to the collection module and the control module respectively. The controller controls the on-off of each switch in the first adjustment module, the second adjustment module, and the voltage conversion module to control the magnitude and direction of the output voltage and current of the conversion circuit.

[0022] The present invention also provides a control method for a magnetic coupling dual-BUCK and single-stage isolated PFC conversion circuit, including the following steps:

[0023] S1. Collect actual circuit parameters through a preset collection module;

[0024] S2. Analyze the difference between the actual circuit parameters and the preset target circuit parameters through a preset analysis module;

[0025] 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.

[0026] 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:

[0027] Judge the positive and negative cycles of the input waveform of the preset AC port through a preset judgment module and obtain a judgment result;

[0028] The control module performs corresponding logic control on the preset switches according to the judgment result;

[0029] Sample the currents on the first coil and the second coil of the preset dual-channel magnetic coupling inductor through the acquisition module respectively to obtain a sampling result;

[0030] Analyze the sampling result through the analysis module until the currents generated on the first coil and the second coil are in the same value and then superimposed to reduce the ripple current and core loss.

[0031] The beneficial effects of the present invention are as follows:

[0032] The present invention relates to a conversion circuit and a control method based on magnetic coupling dual-BUCK and single-stage isolated PFC, including a rectifier circuit, a transformer circuit and a controller, and an external port includes an AC port and multiple DC ports and is used to connect a power supply or a load. The rectifier circuit includes a first adjustment circuit, a second adjustment circuit and an isolation circuit, and the isolation circuit is used to form electrical isolation. The transformer circuit includes a dual-channel magnetic coupling inductor formed by magnetic coupling of a first coil and a second coil, so that the transformer circuit forms a staggered parallel dual-BUCK circuit. The controller controls the conversion circuit to output a target voltage and current. The present invention uses a dual-channel magnetic coupling inductor to form two BUCK circuits, effectively improving the voltage and current conversion efficiency, reducing the magnetic material loss and lowering the cost; the present invention combines a single-stage isolated PFC rectifier circuit with a dual-BUCK DCDC circuit to form a three-port bidirectional conversion circuit, directly powered by the mains power supply, and realizes the charge and discharge management of the DC output port. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will further illustrate the present invention in conjunction with the drawings and embodiments. The drawings in the following description are only partial embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts:

[0034] Figure 1 is a conversion circuit based on magnetic - coupled dual - BUCK and single - stage isolated PFC in an embodiment of the present invention;

[0035] Figure 2 is the control circuit diagram of a conversion circuit based on magnetic - coupled dual - BUCK and single - stage isolated PFC in an embodiment of the present invention;

[0036] Figure 3 is the simulation waveform diagram of the voltage and current of the AC port changing with time in an embodiment of the present invention;

[0037] Figure 4 is the control timing diagram of the controller for each control switch when the AC port is used as the input, and the first DC port and the second DC port are used as the output ports, and the AC port inputs AC power in the positive half - cycle in an embodiment of the present invention;

[0038] Figure 5 is the control timing diagram of the controller for each control switch when the AC port is used as the input, and the first DC port and the second DC port are used as the output ports, and the AC port inputs AC power in the negative half - cycle in an embodiment of the present invention;

[0039] Figure 6 is the simulation waveform diagram of the voltages of the first winding, the second winding, and the third winding of the three - winding transformer changing with time in an embodiment of the present invention;

[0040] Figure 7 is the overall simulation waveform diagram of the current of the first inductor changing with time in an embodiment of the present invention;

[0041] Figure 8 is the expanded simulation waveform diagram of the current of the first inductor changing with time in an embodiment of the present invention;

[0042] Figure 9 is the simulation waveform diagram of the output current of the first DC port changing with time in an embodiment of the present invention;

[0043] Figure 10 is the simulation waveform diagram of the current of the dual - channel magnetic - coupled inductor changing with time in an embodiment of the present invention;

[0044] Figure 11 is the simulation waveform diagram of the output current of the second DC port changing with time in an embodiment of the present invention;

[0045] Figure 12 is the structural diagram of a device based on a conversion circuit of magnetic - coupled dual - BUCK and single - stage isolated PFC in an embodiment of the present invention;

[0046] Figure 13 is the three - dimensional diagram of the dual - channel magnetic - coupled inductor in an embodiment of the present invention;

[0047] Figure 14 It is an exploded view of a dual-channel magnetic coupling inductor in an embodiment of the present invention;

[0048] Figure 15 It is a magnetic simulation diagram of the dual-channel magnetic coupling inductor in an embodiment of the present invention;

[0049] Figure 16 It is a flowchart of a control method for a magnetic coupling dual-BUCK and single-stage isolated PFC conversion circuit in an embodiment of the present invention.

[0050] Label description: Q1, the first switch; Q2, the second switch; Q3, the third switch; Q4, the fourth switch; Q5, the fifth switch; Q6, the sixth switch; Q7, the seventh switch; Q8, the eighth switch; Q9, the ninth switch; Q10, the tenth switch; Q11, the eleventh switch; Q12, the twelfth switch; Q13, the thirteenth switch; Q14, the fourteenth switch; Q15, the fifteenth switch; Q16, the sixteenth switch; C0, the primary capacitor; L1, the first inductor; C1, the first capacitor; C2, the second capacitor; C3, the third capacitor; L2, the dual-channel magnetic coupling inductor; L2_W1, the first coil; L2_W2, the second coil; C4, the fourth capacitor; T1, the three-winding transformer; T1_W1, the first winding; T1_W2, the second winding; T1_W3, the third winding; Vac1, the AC port; Vdc1, the first DC port; Vdc2, the second DC port; 10, the first adjustment module; 20, the second adjustment module; 30, the transformer module; 40, the controller; 401, the acquisition module; 402, the analysis module; 403, the control module; 404, the judgment module; 50, the isolation module; 1, the common magnetic core; 2, the non-common magnetic core. Detailed implementation manners

[0051] In order to make the objectives, technical solutions and advantages of the present application clearer, 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.

[0052] Please refer to the appendix Figures 1-16, the present invention proposes a conversion circuit based on magnetic coupling double BUCK and single-stage isolated PFC, which includes a rectifier circuit and a transformer circuit. An isolation circuit is provided in the rectifier circuit, and the isolation circuit is used to provide electrical isolation so that the rectifier circuit forms a single-stage isolated PFC circuit; the transformer circuit includes multiple coils, and the magnetic circuits of the coils are coupled to each other. The coils are located on the second inductor of the transformer circuit, so that the second inductor forms a multi-channel magnetic coupling inductor. The coils act on different branches of the transformer circuit respectively to form multiple BUCK circuits; the transformer circuit is electrically connected to the rectifier circuit through the isolation circuit; the external ports of the rectifier circuit and the transformer circuit include an AC port Vac1 and multiple DC ports, and the external ports are used to connect to a power supply or a load.

[0053] In this embodiment, the conversion circuit based on magnetic coupling double BUCK and single-stage isolated PFC includes a rectifier circuit and a transformer circuit. The rectifier circuit includes a first regulation circuit, a second regulation circuit, and an isolation circuit. The external ports of the rectifier circuit and the transformer circuit include an AC port Vac1 and multiple DC ports, and the external ports 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 connected to the load to form a three-port bidirectional output circuit. In a specific embodiment, it is mainly discussed that the external port of the first regulation circuit is the AC port Vac1 and is connected to the power source, and the external ports of the second regulation circuit and the transformer circuit are DC ports and are connected to the load; the first regulation circuit includes multiple switch groups, and any switch group includes multiple switching tubes. The switching tubes are arranged and combined so that the switch group can be controlled bidirectionally. Specifically, the first regulation circuit includes a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a fifth switch Q5, a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, and a primary capacitor C0. The first switch Q1 and the second switch Q2 form a first switch group, the third switch Q3 and the fourth switch Q4 form a second switch group, the fifth switch Q5 and the sixth switch Q6 form a third switch group, and the seventh switch Q7 and the eighth switch Q8 form a fourth switch group. The first switch group and the third switch group constitute a first bridge arm, and the second switch group and the fourth switch group constitute a second bridge arm. The primary capacitor C0, the first bridge arm, and the second bridge arm are connected in parallel with each other. The on-off time in the switch group corresponds to the positive and negative periods of the input waveform of the AC port Vac1; the second regulation circuit includes a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11, a twelfth switch Q12, and a third capacitor C3. The ninth switch Q9 and the eleventh switch Q11 constitute a third bridge arm, and the tenth switch Q10 and the twelfth switch Q12 constitute 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 time of the ninth switch Q9 and the eleventh switch Q11 is opposite, and the on-off time of the tenth switch Q10 and the twelfth switch Q12 is opposite; the first regulation circuit and the second regulation circuit are connected through an isolation circuit. The isolation circuit is used to provide electrical isolation so that the rectifier circuit forms a single-stage isolated PFC circuit. The PFC (Power Factor Correction) rectifier circuit reduces the harmonic distortion of the input current, making the output current waveform closer to a sine wave, thereby improving the power factor; the transformer circuit includes multiple coils, and the magnetic circuits of the coils are coupled to each other. The coils are located on the second inductor of the transformer circuit, so that the second inductor forms a multi-channel magnetic coupling inductor. The coils act on different branches of the transformer circuit to form multiple BUCK circuits. In a specific embodiment, the coils include a first coil L2_W1 and a second coil L2_W2, and the multi-channel magnetic coupling inductor is a two-channel magnetic coupling inductor L2;The transformer circuit further includes a thirteenth switch Q13, a fourteenth switch Q14, a fifteenth switch Q15, a sixteenth switch Q16, and a fourth capacitor C4. The thirteenth switch Q13, the fifteenth switch Q15, and the first coil L2_W1 form a first BUCK branch, and the fourteenth switch Q14, the sixteenth switch Q16, and the second coil L2_W2 form a second BUCK branch. The first BUCK branch and the second BUCK branch are interleaved and paralleled and share the fourth capacitor C4. There is a region where the on-off times of the thirteenth switch Q13 and the fifteenth switch Q15 are opposite in part, and there is a region where the on-off times of the fourteenth switch Q14 and the sixteenth switch Q16 are opposite in part, and a phase difference of 0 to 180 degrees is formed between the thirteenth switch Q13 and the fourteenth switch Q14. The transformer circuit is electrically connected to the rectifier circuit through an isolation circuit, and the on-off times of the thirteenth switch Q13, the fourteenth switch Q14, the fifteenth switch Q15, and the sixteenth switch Q16 are controlled according to the magnitude and direction of the current and voltage in the isolation circuit to control the magnitude and direction of the output voltage and current at the external port of the transformer circuit. In a specific embodiment, the switches included in the conversion circuit can be semiconductor switches such as SiC (silicon carbide), GaN (gallium nitride), IGBT (Insulated-Gate Bipolar Transistor), and MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The first inductor L1 is a resonant inductor for storing and transmitting energy. The primary capacitor C0 and the third capacitor C3 are high-frequency filtering capacitors for filtering high-frequency noise and interference to ensure the stability and signal quality of the circuit. The first capacitor C1 and the second capacitor C2 are both DC-blocking capacitors for blocking DC signals and allowing AC signals to pass through. The fourth capacitor C4 is an energy storage and filtering capacitor for storing energy and filtering noise and interference.;

[0054] The present invention proposes to use a dual-channel magnetic coupling inductor L2. The dual-channel magnetic coupling inductor L2 includes a first coil L2_W1 and a second coil L2_W2. A common magnetic core 1 is provided between the first coil L2_W1 and the second coil L2_W2 to form magnetic circuit coupling. The first coil L2_W1 and the second coil L2_W2 act on different branches of the transformer circuit respectively, and two interleaved and paralleled BUCK circuits are formed, effectively improving the voltage-current conversion efficiency, reducing the magnetic material loss, and reducing the cost. The present invention combines a PFC rectifier circuit and a dual-BUCK DCDC circuit to form a three-port bidirectional conversion circuit, which is directly powered by the mains AC power to realize the charge and discharge management of the other two ports.

[0055] Please refer to Figures 1-3, The conversion circuit based on magnetic coupling double BUCK and single-stage isolation PFC includes a rectification circuit and a transformation circuit. The rectification circuit includes a first regulation circuit, a second regulation circuit and an isolation circuit. The external ports of the rectification circuit and the transformation circuit include an AC port Vac1 and multiple DC ports, and the external ports are used to connect a power supply or a load. Among them, any one of the external ports is selected to connect the power supply, and the remaining two external ports are connected to the load, forming a three-port bidirectional output circuit.

[0056] In specific implementation: The first regulation circuit, the second regulation circuit and the transformation circuit each include an external port, and the external ports include an AC port Vac1 and multiple DC ports, and are used to connect a power supply or a load. Among them, any one of the external ports is selected to connect the power supply, and the remaining two external ports are used to connect the load. The power supply supplies power and the load consumes power, forming a three-port bidirectional dual-port output circuit. In a specific embodiment, it is mainly discussed that the external port of the first regulation circuit is the AC port Vac1 and is connected to the power supply, and the external ports of the second regulation circuit and the transformation circuit are DC ports and are connected to the load. At this time, the external port of the first regulation circuit is the AC port Vac1, the external port of the second regulation circuit is the first DC port Vdc1, and the external port of the transformation circuit is the second DC port Vdc2. The AC port Vac1 is connected to the mains, the first DC port Vdc1 and the second DC port Vdc2 are connected to the load, and the current flows in from the AC port Vac1 and flows out from the first DC port Vdc1 and the second DC port Vdc2 respectively. There is no need to pre-rectify the mains, and the mains is directly used for power supply to realize the charge and discharge management of the other two ports; it can be specifically applied to new energy vehicles. The AC port Vac1 is connected to the mains to input electrical energy to the conversion circuit. The first DC port Vdc1 is used to charge the power battery of the new energy vehicle, and the second DC port Vdc2 is used to supply power to the low-voltage equipment on the vehicle.

[0057] More specifically, as Figure 3 shown, it is the simulation waveform diagram of the voltage and current of the AC port Vac1 changing with time when the AC port Vac1 is used as the input and the first DC port Vdc1 and the second DC port Vdc2 are used as the output ports. Among them, the input waveform of the AC port Vac1 has a positive half cycle and a negative half cycle.

[0058] Please refer to Figure 1 and Figure 2, the first adjustment circuit and the second adjustment circuit are connected through an isolation circuit, and the isolation circuit is used to provide electrical isolation so that the rectification circuit forms a single-stage isolated PFC circuit; the transformer circuit is electrically connected to the rectification circuit through the isolation circuit; the isolation circuit includes a first capacitor C1, a first inductor L1, a second capacitor C2, and a three-winding transformer T1. The three-winding transformer T1 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 connected to the first adjustment circuit. The second capacitor C2 and the second winding T1_W2 are connected in series and connected to the second adjustment circuit. The third winding T1_W3 is connected to the transformer circuit; in the isolation circuit, the first inductor L1 and the three-winding transformer T1 include the same magnetic core or different magnetic cores respectively.

[0059] In a specific implementation: The isolation 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 group and the third switch group, and the other end is connected between the second switch group and the fourth switch group. 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; the second capacitor C2 and the second winding T1_W2 are connected in series, and one end is connected between the ninth switch Q9 and the eleventh switch Q11, and the other end is connected between the tenth switch Q10 and the twelfth switch Q12. In a specific embodiment, the series order of the second capacitor C2 and the second winding T1_W2 is not fixed; the isolation circuit is used to provide electrical isolation. The first adjustment circuit and the second adjustment circuit are connected through the isolation circuit and form a single-stage isolated PFC circuit. The PFC (Power Factor Correction) circuit reduces the harmonic distortion of the input current, making the output current waveform closer to a sine wave, thereby improving the power factor; the third winding T1_W3 is respectively connected to the ninth switch Q9 and the tenth switch Q10, and the transformer circuit is electrically connected to the rectification circuit through the isolation circuit; 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-magnetically coupled 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 magnetically coupled form.

[0060] Please refer to Figures 1-8, the first adjustment circuit includes multiple switch groups, any one of the switch groups includes multiple switching tubes, and the switching tubes are arranged and combined so that the switch group can be controlled bidirectionally; the first adjustment circuit includes a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a fifth switch Q5, a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, and a primary capacitor C0. The first switch Q1 and the second switch Q2 form a first switch group, the third switch Q3 and the fourth switch Q4 form a second switch group, the fifth switch Q5 and the sixth switch Q6 form a third switch group, and the seventh switch Q7 and the eighth switch Q8 form a fourth switch group. The first switch group and the third switch group constitute a first bridge arm, and the second switch group and the fourth switch group constitute a second bridge arm. The primary capacitor C0, the first bridge arm, and the second bridge arm are connected in parallel with each other. The on-off time in the switch group corresponds to the positive and negative cycles of the input waveform of the AC port Vac1.

[0061] In a specific implementation: the first adjustment circuit includes multiple switch groups, any one of the switch groups includes multiple switching tubes, and the switching tubes are arranged and combined so that the switch group can be controlled bidirectionally. In a specific embodiment, a switch group can include two switching tubes, and the switching tubes can use IGBT (Insulated Gate Bipolar Transistor) or MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The transistor itself carries a diode, and the diode has a freewheeling effect. Connect the collectors of the IGBT transistors in the switch group to each other or the emitters to each other, or connect the sources of the MOSFET transistors in the switch group to each other or the drains to each other. The connection method can be direct connection or connection on a PCB (Printed Circuit Board), or connection at the chip wafer level, so as to achieve the bidirectional control of the switch group.

[0062] More specifically, the first regulating circuit includes a first switch group, a second switch group, a third switch group, a fourth switch group, and a primary capacitor C0. The first switch group includes a first switch Q1 and a second switch Q2. The second switch group includes a third switch Q3 and a fourth switch Q4. The third switch group includes a fifth switch Q5 and a sixth switch Q6. The fourth switch group includes a seventh switch Q7 and an eighth switch Q8. The first switch group and the third switch group form a first arm, and the second switch group and the fourth switch group form a second arm. The first arm, the second arm, and the primary capacitor C0 are connected in parallel to the AC port Vac1. The on-off time of the switch groups corresponds to the positive and negative cycles of the input waveform of the AC port Vac1. By controlling the on-off time of the first switch group, the second switch group, the third switch group, and the fourth switch group, the magnitude and direction of the voltage and current flowing into the second regulating circuit and the transformer circuit are controlled. In a specific embodiment, the on-off time of the first switch group, the second switch group, the third switch group, and the fourth switch group determines the magnitude and direction of the current and voltage of 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 magnitude and direction of the current and voltage in the second winding T1_W2 and the third winding T1_W3, that is, the magnitude and direction of the voltage and current flowing into the second regulating circuit and the transformer circuit are controlled.

[0063] More specifically, when the AC port Vac1 is used as the input and the first DC port Vdc1 and the second DC port Vdc2 are used as the output ports, when the sine wave input at the AC port Vac1 is in the positive half-cycle, the second switch Q2, the fourth switch Q4, the sixth switch Q6, and the eighth switch Q8 are opened simultaneously. The first switch Q1 and the fifth switch are not opened simultaneously, and the third switch Q3 and the seventh switch Q7 are not opened simultaneously. The specific control timing diagram is as Figure 4 shown; when the sine wave input at the AC port Vac1 is in the negative half-cycle, the first switch Q1, the third switch Q3, the fifth switch Q5, and the seventh switch Q7 are opened simultaneously. The second switch Q2 and the sixth switch are not opened simultaneously, and the fourth switch Q4 and the eighth switch Q8 are not opened simultaneously. The specific control timing diagram is as Figure 5 shown; according to the control timing, the simulation waveform diagram of the voltage change with time of the first winding T1_W1, the second winding T1_W2, and the third winding T1_W3 of the three-winding transformer T1 is as Figure 6 shown; the overall simulation waveform diagram of the current change with time of the first inductor L1 is as Figure 7 shown, and the expanded simulation waveform diagram of the current change with time of the first inductor L1 is as Figure 8 shown.

[0064] Please refer to Figures 1-9, the second regulating circuit includes a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11, a twelfth switch Q12 and a third capacitor C3. The ninth switch Q9 and the eleventh switch Q11 form a third bridge arm, and the tenth switch Q10 and the twelfth switch Q12 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 ninth switch Q9 and the eleventh switch Q11 are opposite, and the on-off times of the tenth switch Q10 and the twelfth switch Q12 are opposite.

[0065] In specific implementation: The second regulating circuit includes a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11, a twelfth switch Q12 and a third capacitor C3. The ninth switch Q9 and the eleventh switch Q11 form a third bridge arm, and the tenth switch Q10 and the eleventh switch Q11 form a fourth bridge arm. The third bridge arm, the fourth bridge arm and the third capacitor C3 are connected in parallel to the first DC port Vdc1. The on-off times of the ninth switch Q9 and the eleventh switch Q11 are opposite, the on-off times of the tenth switch Q10 and the twelfth switch Q12 are opposite, the on-off times of the ninth switch Q9 and the twelfth switch Q12 are the same, and the on-off times of the tenth switch Q10 and the eleventh switch Q11 are the same. 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 second regulating circuit can be controlled. 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 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 second regulating circuit can be realized.

[0066] More specifically, when the AC port Vac1 is used as the input and the first DC port Vdc1 and the second DC port Vdc2 are used as the output ports, according to the two control timing diagrams of each control switch by the controller 40, the simulation waveform diagram of the output current of the external port of the second regulating circuit, that is, the first DC port Vdc1, changing with time is obtained, as Figure 9 shown.

[0067] Please refer to Figures 1-11, the voltage conversion circuit includes a dual-channel magnetically coupled inductor L2, a thirteenth switch Q13, a fourteenth switch Q14, a fifteenth switch Q15, a sixteenth switch Q16, and a fourth capacitor C4. The dual-channel magnetically 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 share a magnetic core 1 and are magnetically coupled. The thirteenth switch Q13, the fifteenth switch Q15, and the first coil L2_W1 form a first BUCK branch, and the fourteenth switch Q14, the sixteenth switch Q16, and the second coil L2_W2 form a second BUCK branch. The first BUCK branch and the second BUCK branch are interleaved and parallel, and share the fourth capacitor C4. The on-off times of the fourteenth switch Q14 and the sixteenth switch Q16 are opposite, and there is a phase difference of 0 to 180 degrees between the thirteenth switch Q13 and the fourteenth switch Q14.

[0068] In specific implementation: The voltage conversion circuit includes a dual-channel magnetically coupled inductor L2. The dual-channel magnetically coupled inductor L2 includes a first coil L2_W1, a second coil L2_W2, and a shared magnetic core 1. The shared magnetic core 1 is located in the middle of 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 shared 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 an interleaved and parallel dual-BUCK circuit. The BUCK circuit is a buck chopper circuit, which realizes the buck conversion from DC to DC. The voltage conversion circuit also includes a thirteenth switch Q13, a fourteenth switch Q14, a sixteenth switch Q16, a fifteenth switch Q15, and a fourth capacitor C4. The thirteenth switch Q13, the fifteenth switch Q15, and the first coil L2_W1 of the dual-channel magnetically coupled inductor L2 form a first branch, and the fourteenth switch Q14, the sixteenth switch Q16, and the second coil L2_W2 of the dual-channel magnetically coupled inductor L2 form a second branch. The first branch and the second branch share the fourth capacitor C4 and form two interleaved and parallel BUCK branches. The on-off times of the thirteenth switch Q13 and the fifteenth switch Q15 are opposite, the on-off times of the fourteenth switch Q14 and the sixteenth switch Q16 are opposite, and there is a phase difference of 0 to 180 degrees between the thirteenth switch Q13 and the fourteenth switch Q14. By controlling the on-off times of the thirteenth switch Q13, the fourteenth switch Q14, the sixteenth switch Q16, and the fifteenth switch Q15, the magnitude and direction of the output voltage and current of the external port of the voltage conversion circuit are controlled.

[0069] More specifically, when the AC port Vac1 is used as the input and the first DC port Vdc1 and the second DC port Vdc2 are used as the output ports, the currents of the first coil L2_W1 and the second coil L2_W2 of the dual-channel magnetically coupled inductor L2 have a certain phase difference, such as Figure 10As shown, since the pins of the first coil L2_W1 and the second coil L2_W2 do not have a fixed polarity direction, the two current transformation curves need to be determined according to the specific connection method of the coils. After the currents of the first coil L2_W1 and the second coil L2_W2 are superimposed, the ripple current and core loss are reduced. The simulation waveform diagram of the output current of the second DC port Vdc2 changing with time is as Figure 11 shown.

[0070] Please refer to Figures 12-15 , a device of a conversion circuit based on a magnetic coupling double BUCK and a single-stage isolated PFC, including a rectification module, a voltage conversion module 30 and a controller 40. The rectification module includes a first adjustment module 10, a second adjustment module 20 and an isolation module 50. The isolation module 50 is used to connect the first adjustment module 10, the second adjustment module 20 and the voltage conversion module 30 to form electrical isolation. The external ports of the first adjustment module 10, the second adjustment module 20 and the voltage conversion module 30 include an AC port Vac1 and multiple DC ports, and the external ports are used to connect to a power supply or a load. The voltage conversion module 30 includes a multi-channel magnetic coupling inductor, and the multi-channel magnetic coupling inductor includes a first coil L2_W1 and a second coil L2_W2 with magnetically coupled paths. The controller 40 includes a collection module 401, an analysis module 402, a judgment module 404 and a control module 403. The analysis module 402 and the judgment module 404 are electrically connected to the collection module 401 and the control module 403 respectively. The controller 40 controls the on and off of each switch in the first adjustment module 10, the second adjustment module 20 and the voltage conversion module 30 to control the magnitude and direction of the output voltage and current of the conversion circuit.

[0071] In specific implementation: the voltage conversion module 30 includes a two-channel magnetic coupling inductor L2. The two-channel magnetic coupling 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 magnetically coupled path, effectively reducing the volume of the device, reducing the magnetic material loss and reducing the cost.

[0072] More specifically, Figure 15It is the magnetic simulation diagram of the dual-channel magnetic coupling inductor L2. When current flows into the dual-channel magnetic coupling inductor L2, the dual-channel magnetic coupling inductor L2 converts voltage and current into magnetic energy for storage. In the figure, red represents a very high magnetic flux density. 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 smaller losses 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 common magnetic core 1 of the two inductors is green, and even blue areas appear, indicating that after the magnetic fields of the common magnetic path are superimposed and cancelled each other, the magnetic material loss is greatly reduced, the conversion efficiency is improved, and the heating of the inductor is reduced.

[0073] Please refer to the appendix Figures 1-16 In an embodiment of the present invention, a control method for a magnetic coupling dual-BUCK and single-stage isolated PFC conversion circuit includes the following steps:

[0074] S1. Collect actual circuit parameters through a preset acquisition module 401;

[0075] S2. Analyze the difference between the actual circuit parameters and the target circuit parameters through a preset analysis module 402;

[0076] S3. Control the on and off of each switch through a preset control module 403 until the actual circuit parameters are equal to the target circuit parameters.

[0077] Among them, in the step of controlling the on and 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:

[0078] Judge the positive and negative cycles of the input waveform of the preset AC port Vac1 through a preset judgment module 404, and obtain a judgment result;

[0079] The control module 403 performs corresponding logical control on the preset switches according to the judgment result;

[0080] 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 a sampling result;

[0081] Analyze the sampling result through the analysis module 402 until the currents generated on the first coil L2_W1 and the second coil L2_W2 are in the same value and then superimposed to reduce the ripple current and core loss.

[0082] In the above steps, first, the actual circuit parameters are collected by the preset acquisition module 401. In a specific embodiment, the controller 40 is first electrically connected to the first bridge circuit, the second bridge circuit, and the transformer circuit. After a sine wave is input at the AC port Vac1, the acquisition module 401 of the controller 40 collects the actual circuit parameters in the circuit. The actual circuit parameters mainly include the voltage and current of the AC port Vac1, the terminal voltages of the three windings of the three-winding transformer T1, the current of the first inductor L1, the output current of the first DC port Vdc1, the currents of the two-channel magnetic coupling inductor L2, and the output current of the second DC port Vdc2. More specifically, the acquisition module 401 samples the currents on the first coil L2_W1 and the second coil L2_W2 of the preset two-channel magnetic coupling inductor L2 respectively to obtain the sampling results. Then, the difference between the actual circuit parameters and the target circuit parameters is analyzed by the preset analysis module 402. In a specific embodiment, first, the preset judgment module 404 judges the positive and negative cycles of the input waveform of the preset AC port Vac1 and obtains the judgment result. The control module 403 performs corresponding logic control on the preset switches according to the judgment result until the currents generated on the first coil L2_W1 and the second coil L2_W2 are superimposed to reduce the ripple current and core loss. More specifically, when an alternating current is input at the AC port Vac1 in the positive half cycle, the control timing diagram of the controller 40 for each control switch is as shown in Figure 4 shown; when an alternating current is input at the AC port Vac1 in the negative half cycle, the control timing diagram of the controller 40 for each control switch is as shown in Figure 5 shown; by analyzing 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 two-channel magnetic coupling inductor L2, as shown in Figure 10 shown. Until the currents of the first coil L2_W1 and the second coil L2_W2 are the same and then superimposed, so that the second DC port Vdc2 outputs direct current to reduce the ripple current and core loss, as shown in Figure 11 shown.

[0083] It should be noted that in this article, the terms "include", "comprise" or any other variant thereof are 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 expressly listed, or also includes elements inherent to such process, device, article or method. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of another identical element in the process, device, article or method including that element.

[0084] 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 conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC, characterized in that: It comprises a rectifier circuit and a transformer circuit, wherein the rectifier circuit is provided with an isolation circuit, and the isolation circuit is used to provide electrical isolation so that the rectifier circuit forms a single-stage isolated PFC circuit; The transformer circuit includes a plurality of coils, and the coils are magnetically coupled, the coils are located on a second inductor of the transformer circuit, so that the second inductor forms a multi-channel magnetically coupled inductor, and the coils act on different branches of the transformer circuit respectively to form a plurality of BUCK circuits; The voltage transformation circuit is electrically connected to the rectification circuit through the isolation circuit; The external ports of the rectifier circuit and the transformer circuit include an AC port and a plurality of DC ports, and the external ports are used to connect a power source or a load.

2. The conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC according to claim 1 is characterized in that: The rectifier circuit further includes a first regulating circuit and a second regulating circuit, and the first regulating circuit and the second regulating circuit are connected via the isolation circuit.

3. The conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC according to claim 2 is characterized in that: The isolation circuit includes a first capacitor, a first inductor, a second capacitor and a three-winding transformer, the three-winding 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 and connected to the first regulating circuit, the second capacitor and the second winding are connected in series and connected to the second regulating circuit, and the third winding is connected to the voltage transformation circuit; In the isolation circuit, the first inductor and the three-winding transformer include the same magnetic core or different magnetic cores.

4. The conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC according to claim 3 is characterized in that: The first regulating circuit includes a plurality of switch groups, any of which includes a plurality of switch tubes, and the switch tubes are arranged and combined so that the switch group can be bidirectionally controlled.

5. The conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC according to claim 4 is characterized in that: The first regulating circuit comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch and a primary capacitor, the first switch and the second switch form a first switch group, the third switch and the fourth switch form a second switch group, the fifth switch and the sixth switch form a third switch group, the seventh switch and the eighth switch form a fourth switch group, the first switch group and the third switch group form a first bridge arm, the second switch group and the fourth switch group form a second bridge arm, and the primary capacitor, the first bridge arm and the second bridge arm are connected in parallel with each other; The on-off time of the switch group corresponds to the positive and negative cycles of the input waveform of the AC port.

6. The conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC according to claim 5 is characterized in that: The second regulating circuit includes a ninth switch, a tenth switch, an eleventh switch, a twelfth switch and a third capacitor, the ninth switch and the eleventh switch constitute a third bridge arm, the tenth switch and the twelfth switch constitute 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 ninth switch and the eleventh switch are opposite, and the on-off time of the tenth switch and the twelfth switch are opposite.

7. The conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC according to claim 6 is characterized in that: The coil includes a first coil and a second coil; the voltage conversion circuit also includes a thirteenth switch, a fourteenth switch, a fifteenth switch, a sixteenth switch and a fourth capacitor, the thirteenth switch, the fifteenth switch and the first coil of the multi-channel magnetic coupling inductor form a first BUCK branch, the fourteenth switch, the sixteenth switch and the second coil of the multi-channel magnetic coupling inductor form a second BUCK branch, the first BUCK branch and the second BUCK branch are staggered in parallel and share the fourth capacitor; There is a region with opposite on-off times between the thirteenth switch and the fifteenth switch, there is a region with opposite on-off times between the fourteenth switch and the sixteenth switch, and the thirteenth switch forms a phase difference of 0 to 180 degrees with the fourteenth switch.

8. A device based on a conversion circuit of a magnetically coupled dual-BUCK and a single-stage isolated PFC, characterized in that: It includes a rectifier module, a transformer module and a controller, wherein the rectifier module includes a first regulating module, a second regulating module and an isolation module, wherein the isolation module is used to connect the first regulating module, the second regulating module and the transformer module to form electrical isolation; the external ports of the first regulating module, the second regulating module and the transformer module include an AC port and a plurality of DC ports, and the external ports are used to connect a power source or a load; The transformer module includes a multi-channel magnetically coupled inductor, which includes a first coil, a second coil, a non-shared magnetic core and a shared magnetic core, wherein the non-shared magnetic cores are respectively located outside the first coil and the second coil and tightly surround the first coil and the second coil, 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 a magnetic circuit coupling; The controller includes an acquisition module, an analysis module, a judgment module and a control module. The analysis module and the judgment module are electrically connected to the acquisition module and the control module respectively. The controller controls the on and off of each switch in the first regulation module, the second regulation module and the transformer module to control the magnitude and direction of the output voltage and current of the conversion circuit.

9. A control method for a conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC, 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 of the conversion circuit based on magnetically coupled dual BUCK and single-stage isolated PFC according to claim 9, 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 positive and negative cycles of the preset AC port input waveform are judged by a preset judgment module, and a judgment result is obtained; The control module performs corresponding logic control on the preset switch according to the judgment result; The current on the first coil and the second coil of the preset multi-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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