Direct current conversion method and device based on multi-source input

Abstract

The invention discloses a direct current conversion method and device based on multi-source input. The direct current conversion method and device are suitable for a power supply comprising a first power supply and a second power supply. Wherein the output end of the power supply is electrically connected with the input end of the voltage conversion circuit; the output end of the voltage conversion circuit is electrically connected with the direct current input interface; the direct-current conversion method comprises the following steps: controlling the voltage conversion circuit to construct a direct-current conversion channel of a first power supply and a direct-current input interface; connecting a second power supply with an energy transmission channel of the DC conversion channel; and controlling the voltage conversion circuit to obtain the output voltage of the power supply based on the direct current conversion channel and the energy transmission channel, and controlling the voltage conversion circuit to transform the output voltage so as to output a second voltage to the direct current input interface, thereby reducing the circuit complexity of converting multiple paths of direct current input.

Description

Technical Field

[0001] The present invention relates to the technical field of converters, and in particular to a direct current conversion method and device based on multi-source input. Background Art

[0002] With the decline of traditional energy, electric energy has gradually been valued. In order to expand the application areas of electric energy, DC / DC converters, as a device that can convert one type of direct current into another type of direct current with different frequencies or voltages, have gradually been widely used in various fields such as DC microgrids, transportation electrification, and data center power supply systems.

[0003] In the prior art, most DC / DC converters are used for single-channel DC input, that is, they can only obtain DC input from a single power source and output it. When using the DC / DC converter for DC conversion, for applications that require multi-source DC input or bidirectional energy flow, multiple DC-DC converters need to be used in parallel, that is, each DC input needs to be equipped with a separate converter to achieve multi-source DC input and output. The method of using the existing converter for DC conversion needs to increase the number of required circuit components by multiples according to the number of DC inputs, thereby increasing the complexity of the circuit. Summary of the invention

[0004] In order to solve the above technical problems, the present invention discloses a DC conversion method and device based on multi-source input, which are used to reduce the circuit complexity of converting multiple DC inputs.

[0005] To achieve the above object, the present invention discloses a DC conversion method based on multi-source input, which is applicable to a power supply including a first power supply and a second power supply; wherein the output end of the power supply is electrically connected to the input end of a voltage conversion circuit; the output end of the voltage conversion circuit is electrically connected to a DC input interface; the DC conversion method comprises:

[0006] Controlling the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface;

[0007] In response to a power supply demand, connecting an energy transmission channel between the second power supply and the DC conversion channel;

[0008] Controlling the voltage conversion circuit based on the DC conversion channel to obtain a first voltage of the first power supply, and controlling the voltage conversion circuit based on the energy transmission channel to obtain a second voltage of the second power supply;

[0009] The first voltage and the second voltage are used as the output voltage of the power supply, and the voltage conversion circuit is controlled to transform the output voltage so as to output the second voltage to the DC input interface.

[0010] The present invention discloses a DC conversion device based on multi-source input, which is suitable for a power supply including multiple power supplies to realize multi-channel DC input. In the process of realizing multi-channel DC input, a DC conversion channel between a first power supply and a DC input interface is first constructed to send the energy of the first power supply to the DC input interface. Furthermore, after the DC conversion channel is constructed, an energy transmission channel between a second power supply and the DC conversion channel is constructed according to power supply requirements to receive multiple DC inputs based on the same DC conversion channel, so as to reduce the number of devices required for DC conversion, thereby reducing the complexity of the circuit.

[0011] As a preferred example, the step of constructing a DC output channel between the output end and the DC input interface, and outputting the second voltage to the DC input interface based on the DC output channel, further includes:

[0012] Controlling the DC output channel to obtain a second voltage output by the voltage conversion circuit;

[0013] The DC output channel is controlled to filter the acquired second voltage, and the filtered second voltage is output to the DC input interface.

[0014] In the above scheme, the converted DC output is filtered to eliminate the AC in the DC output, thereby improving the effect of DC conversion.

[0015] On the other hand, the present invention discloses a DC conversion device based on multi-source input, which is applicable to a power supply including a first power supply and a second power supply; wherein the DC conversion device includes a controller, a voltage conversion circuit and a power supply switching circuit;

[0016] The first end of the power switching circuit is electrically connected to the first end of the second power supply; the second end of the power switching circuit and the first end of the first power supply are electrically connected to the first end of the voltage conversion circuit respectively; the second end of the voltage conversion circuit is electrically connected to the DC input interface;

[0017] The voltage conversion circuit is connected to the controller signal so that the controller controls the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface;

[0018] The power switching circuit is connected to the controller signal so that the controller controls the power switching circuit to connect the energy transmission channel between the second power source and the DC conversion channel;

[0019] The controller controls the voltage conversion circuit to obtain the first voltage of the first power supply based on the DC conversion channel, and controls the voltage conversion circuit to obtain the second voltage of the second power supply based on the energy transmission channel, and uses the first voltage and the second voltage as the output voltage of the power supply to control the voltage conversion circuit to transform the output voltage and output the second voltage to the DC input interface.

[0020] The present invention discloses a DC conversion device based on multi-source input, which is suitable for a power supply including multiple power supplies to realize multi-channel DC input. In the process of realizing multi-channel DC input, a voltage conversion circuit is first set to be connected to the power supply and the external DC input interface respectively, so as to realize the conversion of DC and the bidirectional flow of energy through the voltage conversion circuit, thereby reducing the number of devices required for the bidirectional flow of energy. Furthermore, a power switching circuit with the same number as the second power supply in the power supply is connected in series at the first end of the voltage conversion circuit, so as to connect the additional DC input in series to the existing voltage conversion circuit through the power switching circuit, and then realize the conversion of multi-channel DC input through one voltage conversion circuit and the power switching circuit, thereby reducing the number of devices required for DC conversion and reducing the complexity of the circuit.

[0021] As a preferred example, the power switching circuit includes a first switch tube and a second switch tube;

[0022] Wherein, the source of the first switch tube is connected to the first end of the second power supply; the drain of the first switch tube is connected to the first input end of the voltage conversion circuit;

[0023] The drain of the second switch tube is connected to the first end of the second power supply, and the source of the second switch tube is connected to the second input end of the voltage conversion circuit; wherein the first end of the voltage conversion circuit includes a first input end and a second input end.

[0024] In the above scheme, in order to respond to the DC input of each second power supply, a first switch tube and a second switch tube are set in each power switching switch circuit to realize the energy input of the second power supply by controlling the conduction of the switch tube, wherein the source of the first switch tube is connected to the first end of the second power supply, and the drain of the second switch tube is connected to the first end of the second power supply, and the first power supply can be charged by the second power supply.

[0025] As a preferred example, the power switching circuit further includes a first inductor and a second inductor;

[0026] Wherein, the first end of the first inductor is connected to the drain of the first switch tube; the second end of the first inductor is connected to the first input end of the voltage conversion circuit;

[0027] The first end of the second inductor is connected to the source of the second switch tube; the second end of the second inductor is connected to the second input end of the voltage conversion circuit.

[0028] In the above scheme, an inductor is connected in series between different switch tubes in the power switching circuit to process the DC output of the second power supply through the inductor and charge the first power supply based on the conduction state of the first switch tube.

[0029] As a preferred example, the voltage conversion circuit includes a transformer, a third switch tube, a fourth switch tube, a fifth switch tube, a sixth switch tube, a seventh switch tube, an eighth switch tube, a ninth switch tube and a tenth switch tube;

[0030] Wherein, the drain of the third switch tube is electrically connected to the discharge end of the first power supply; the source of the third switch tube is electrically connected to the first input end of the transformer;

[0031] The drain of the fourth switch tube is electrically connected to the first input terminal of the transformer; the source of the fourth switch tube is electrically connected to the charging terminal of the first power supply; the source of the fourth switch tube is electrically connected to the charging terminal of the second power supply; wherein the first terminal of the first power supply includes the discharging terminal and the charging terminal; the charging terminal of the second power supply is the second terminal of the second power supply;

[0032] The drain of the fifth switch tube is electrically connected to the drain of the third switch tube; the source of the fifth switch tube is electrically connected to the second input terminal of the transformer;

[0033] The drain of the sixth switch tube is electrically connected to the second input terminal of the transformer; the source of the sixth switch tube is electrically connected to the source of the fourth switch tube;

[0034] The source of the seventh switch tube is electrically connected to the first output terminal of the transformer; the drain of the eighth switch tube is electrically connected to the first output terminal of the transformer;

[0035] The drain of the ninth switch tube is electrically connected to the drain of the seventh switch tube; the source of the ninth switch tube is electrically connected to the second output end of the transformer;

[0036] The drain of the tenth switch tube is electrically connected to the second output end of the transformer; the source of the tenth switch tube is electrically connected to the source of the eighth switch tube.

[0037] In the above scheme, the transformer is provided to realize voltage conversion, so as to adapt to DC input and DC output with different voltage values. Furthermore, in order to realize the control of energy flow through the transformer, different switch tubes are respectively provided at both ends of the transformer to control the DC output to the external DC input interface. Among them, the connection mode between different switch tubes enables the voltage conversion circuit to have a bidirectional energy flow effect by controlling the third switch tube and the sixth switch tube to be turned on at the same time, or the fourth switch tube and the fifth switch tube to be turned on at the same time, and the seventh switch tube and the tenth switch tube to be turned on at the same time, or the eighth switch tube and the ninth switch tube to be in the on state.

[0038] Furthermore, based on the connection between the source of the sixth switch tube and the second end of the second power supply, the first power supply can be charged through the interface of the second power supply based on the conduction state of the first switch tube and the sixth switch tube.

[0039] As a preferred example, the voltage conversion circuit further includes a third inductor and a fourth inductor;

[0040] Wherein, the first end of the third inductor is connected to the first input end of the transformer, and the second end of the third inductor is connected to the primary side of the transformer;

[0041] A first end of the fourth inductor is connected to the first output end of the transformer, and a second end of the fourth inductor is connected to the secondary side of the transformer.

[0042] In the above scheme, inductors are respectively arranged at both ends of the transformer so that energy can be efficiently transmitted between the active bridges corresponding to the two ends of the transformer. At the same time, by adjusting the parameters of the inductor and the on-off state of the switch tube, precise control of the transmission power and output voltage can be achieved, thereby improving the conversion effect.

[0043] As a preferred example, it further includes a filter circuit, which is used to filter the second voltage output by the voltage conversion circuit, and output the filtered second voltage to the DC input interface;

[0044] Wherein, the filtering circuit includes a first capacitor and a fifth inductor; the first end of the first capacitor is connected to the drain of the ninth switch tube; the second end of the first capacitor is connected to the source of the tenth switch tube;

[0045] The first end of the fifth inductor is connected to the first end of the first capacitor; the second end of the fifth inductor is connected to the DC input interface.

[0046] In the above scheme, the filter circuit is provided and capacitors and inductors are provided in the filter circuit to filter the converted DC output to eliminate AC in the DC output and improve the effect of DC conversion.

[0047] As a preferred example, it also includes a plurality of eleventh switching tubes; wherein the drain of each of the eleventh switching tubes is electrically connected to the second end of the fifth inductor; and the source of each of the eleventh switching tubes is electrically connected to each of the DC input interfaces.

[0048] In the above scheme, when connecting the DC conversion device with multiple DC inputs to an external DC input interface, in order to improve the multiple DC outputs of the DC conversion device, a switch tube may be provided in the connection circuit between each DC input interface and the DC conversion device, and multiple outputs may be realized by turning on the switch tube.

[0049] As a preferred example, the controller controls the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface, including:

[0050] The controller performs complementary control on the switch tubes in the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface; wherein the complementary control is used to control the two switch tubes on the same bridge arm not to be turned on or off at the same time.

[0051] In the above scheme, the controller can perform complementary control on different switch tubes on the same bridge arm, that is, it is used to indicate that two complementary controlled switch tubes cannot be turned on or off at the same time. For example, the third switch tube and the fourth switch tube cannot be turned on or off at the same time, and the fifth switch tube and the sixth switch tube cannot be turned on or off at the same time. In other words, the controller can control different switch tubes not to be turned on or off at the same time to achieve bidirectional flow of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 : is a structural schematic diagram of a DC conversion device based on multi-source input disclosed in an embodiment of the present invention;

[0053] Figure 2 : is a schematic diagram of the structure of a power switching circuit disclosed in an embodiment of the present invention;

[0054] Figure 3 : is a schematic diagram of the structure of a voltage conversion circuit disclosed in an embodiment of the present invention;

[0055] Figure 4 : is a structural schematic diagram of a filter circuit disclosed in an embodiment of the present invention;

[0056] Figure 5 : is a schematic diagram of a circuit structure for switching a DC input interface disclosed in an embodiment of the present invention;

[0057] Figure 6: A schematic diagram of a flow chart of a DC conversion method based on multi-source input disclosed in an embodiment of the present invention;

[0058] Figure 7 : A structural schematic diagram of a DC conversion device for dual-channel DC input and output disclosed in another embodiment of the present invention;

[0059] Among them, 101, power supply switching circuit; 102, voltage conversion circuit; 103, controller; 1011, first switch tube; 1012, second switch tube; 1013, first inductor; 1014, second inductor; 301, third switch tube; 302, fourth switch tube; 303, fifth switch tube; 304, sixth switch tube; 305, seventh switch tube; 306, eighth switch tube; 307, ninth switch tube; 308, tenth switch tube; 309, transformer; 310, third inductor; 311, fourth inductor; 401, first capacitor; 402, fifth inductor; 501, eleventh switch tube. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Embodiment 1

[0062] The present disclosure provides a DC conversion device based on multi-source input, which is applicable to a power supply including a first power supply and a second power supply, so as to reduce the complexity of the circuit.

[0063] Specifically, please refer to the specific structural composition of the DC conversion device. Figure 1 .like Figure 1 As shown, the DC conversion device includes a power switching circuit 101, a voltage conversion circuit 102 and a controller 103; wherein the first end of the power switching circuit 101 is electrically connected to the first end of the second power supply; the second end of the power switching circuit 101 and the first end of the first power supply are electrically connected to the first end of the voltage conversion circuit 102 respectively; the second end of the voltage conversion circuit 102 is electrically connected to the DC input interface.

[0064] like Figure 1 As shown, the voltage conversion circuit 102 is connected to the controller 103 by signal, so that the controller 103 controls the voltage conversion circuit 102 to construct a DC conversion channel between the first power supply and the DC input interface;

[0065] The power switching circuit 101 is connected to the controller 103 by signal, so as to connect the energy transmission channel between the second power source and the DC conversion channel according to the control signal sent by the controller 103. In order to adapt to the number of the second power sources, the same number of power switching circuits 101 as the second power sources can be set in the DC conversion device, and each power switching circuit 101 is connected to the second power source and the voltage conversion circuit 102 in the same manner.

[0066] The controller 103 controls the voltage conversion circuit 102 to obtain the first voltage of the first power supply based on the DC conversion channel, and controls the voltage conversion circuit 102 to obtain the second voltage of the second power supply based on the energy transmission channel, and uses the first voltage and the second voltage as the output voltage of the power supply to control the voltage conversion circuit 102 to transform the output voltage and output the second voltage to the DC input interface.

[0067] In some implementations of this embodiment, taking the case where the flow direction is from the power supply to the DC input interface for transmission as an example, firstly, it is determined whether multiple DC inputs are required according to the voltage required by the DC input interface. When it is determined that multiple DC inputs are required, the second power supply is connected to the voltage conversion circuit 102 according to the power supply switching switch 101 corresponding to the second power supply to achieve multiple DC inputs.

[0068] In this embodiment, in order to realize the power supply and charging of the second power source at the same time, two parallel reverse-flow switch tubes can be arranged in the power switching circuit to realize the power supply and discharge of the second power source through different flow directions in the switch tubes.

[0069] Specifically, the structure of the power switch 101 can refer to Figure 2 .like Figure 2 As shown, the power switch 101 includes a first switch tube 1011 and a second switch tube 1012 , a first inductor 1013 and a second inductor 1013 .

[0070] Among them, the source of the first switch tube 1011 is connected to the first end of the second power supply; the drain of the first switch tube 1011 is connected to the first input end of the voltage conversion circuit 102; the drain of the second switch tube 1012 is connected to the first end of the second power supply, and the source of the second switch tube 1012 is connected to the second input end of the voltage conversion circuit 102; wherein the first end of the voltage conversion circuit 102 includes a first input end and a second input end.

[0071] It should be noted that the switch tube in this embodiment can be selected from various types of transistors such as NPN transistors, PNP transistors, etc. When different types of transistors are selected, the connection method between the switch tube and the second power supply can be changed according to the flow direction of each type of transistor.

[0072] Furthermore, when the switch tube is set to control the energy flow direction of the second power supply, in order to better improve the effect of DC output, an inductor can be connected in series at one end of the first switch tube 1011 and the second switch tube 1012 to filter the DC output of the second power supply.

[0073] Specifically, refer to Figure 2 , a first end of the first inductor 1013 is connected to the drain of the first switch tube 1011; a second end of the first inductor 1013 is connected to the first input end of the voltage conversion circuit 102;

[0074] A first end of the second inductor 1013 is connected to the source of the second switch tube 1012 ; a second end of the second inductor 1013 is connected to the second input end of the voltage conversion circuit 102 .

[0075] The power switching switch circuit 101 disclosed in the above scheme is provided with a source of the first switch tube 1011 connected to the first end of the second power supply, and a drain of the second switch tube 1012 connected to the first end of the second power supply. When receiving the DC input of the second power supply, bidirectional input or output of multiple sources can be realized by driving the first power supply or the second power supply to be turned on. Furthermore, an inductor is connected in series between different switch tubes in the power switching switch circuit, which is used to store and release energy through the inductor and control the intermittent conduction of the switch tube, so as to realize the charging of the first power supply by the second power supply.

[0076] In one implementation of the present embodiment, when the voltage conversion circuit 102 is used to connect the power supply and the external DC input interface to achieve DC output, in order to enable the voltage conversion circuit 102 to simultaneously receive the energy provided by the first power supply and the second power supply and send it to the external DC input interface and adapt to the voltage required by the DC input interface, a transformer for voltage transformation and a first-phase bidirectional conversion circuit and a second-phase bidirectional conversion circuit that can control the direction of energy flow may be provided in the voltage conversion circuit 102.

[0077] Specifically, the first-phase bidirectional conversion circuit includes a first group of bridge arms and a second group of bridge arms; wherein the first end of the first power supply and the second end of the second power supply are electrically connected to the first end of the first group of bridge arms respectively; the second end of the first group of bridge arms is electrically connected to the first input end of the transformer; the first input end of the transformer is the first input end of the voltage conversion circuit 102;

[0078] The first end of the second group of bridge arms is electrically connected to the first end of the first group of bridge arms; the second end of the second group of bridge arms is electrically connected to the second input end of the transformer; the second input end of the transformer is the second input end of the voltage conversion circuit 102;

[0079] The second-phase bidirectional conversion circuit includes a third group of bridge arms and a fourth group of bridge arms; wherein the first end of the third group of bridge arms is electrically connected to the first output end of the transformer; the first output end of the transformer is the first output end of the voltage conversion circuit 102;

[0080] The first end of the fourth group of bridge arms is electrically connected to the second end of the third group of bridge arms; the second end of the fourth group of bridge arms is electrically connected to the second output end of the transformer; the second output end of the transformer is the second output end of the voltage conversion circuit 102; wherein the second end of the voltage conversion circuit 102 includes the first output end and the second output end.

[0081] The voltage conversion circuit 102 disclosed in the above scheme is provided with the transformer to realize voltage conversion, thereby adapting to DC input and DC output with different voltage values. Further, in order to realize the flow of energy through the transformer, switch tubes are respectively provided at both ends of the transformer to realize the output of power to the DC input interface by controlling the conduction of the switch tubes. Further, by setting the connection mode of different switch tubes, a bidirectional conversion circuit composed of different bridge arm circuits is formed, and then the energy flow direction of the transformer is controlled by the bidirectional conversion circuit, thereby realizing bidirectional energy flow.

[0082] Furthermore, in order to realize the bidirectional flow of energy through the first group of bridge arms, the second group of bridge arms, the third group of bridge arms, the fourth group of bridge arms and the transformer, in some implementations of this embodiment, a switch tube with a reverse flow direction is provided in each group of bridge arms, and the flow of energy is controlled by the switch tube.

[0083] Specifically, the specific structure of the voltage conversion circuit 102 formed by setting the switch tube is shown in FIG. Figure 3 , mainly including a third switch tube 301 , a fourth switch tube 302 , a fifth switch tube 303 , a sixth switch tube 304 , a seventh switch tube 305 , an eighth switch tube 306 , a ninth switch tube 307 and a tenth switch tube 308 .

[0084] like Figure 3As shown, the drain of the third switch tube 301 and the source of the fourth switch tube 302 are the first end of the first bridge arm; the source of the third switch tube 301 and the drain of the fourth switch tube 302 are the second end of the first bridge arm; the drain of the fifth switch tube 303 and the source of the sixth switch tube 304 are the first end of the second bridge arm; the source of the fifth switch tube 303 and the drain of the sixth switch tube 304 are the second end of the second bridge arm; the source of the seventh switch tube 305 and the drain of the eighth switch tube 306 are the first end of the third bridge arm; the drain of the seventh switch tube 305 and the source of the eighth switch tube 306 are the second end of the third bridge arm; the drain of the ninth switch tube 307 and the source of the tenth switch tube 308 are the first end of the fourth bridge arm; the source of the ninth switch tube 307 and the drain of the tenth switch tube 308 are the second end of the fourth bridge arm.

[0085] like Figure 3 As shown, the drain of the third switch tube 301 is electrically connected to the discharge end of the first power supply; the source of the third switch tube 301 is electrically connected to the first input end of the transformer 309; the drain of the fourth switch tube 302 is electrically connected to the first input end of the transformer 309; the source of the fourth switch tube 302 is electrically connected to the charging end of the first power supply; the source of the fourth switch tube 302 is electrically connected to the charging end of the second power supply; wherein the first end of the first power supply includes the discharge end and the charging end; the charging end of the second power supply is the second end of the second power supply;

[0086] The drain of the fifth switch tube 303 is electrically connected to the drain of the third switch tube 301; the source of the fifth switch tube 303 is electrically connected to the second input end of the transformer 309; the drain of the sixth switch tube 304 is electrically connected to the second input end of the transformer 309; the source of the sixth switch tube 304 is electrically connected to the source of the fourth switch tube 302.

[0087] The source of the seventh switch tube 305 is electrically connected to the first output end of the transformer 309; the drain of the eighth switch tube 306 is electrically connected to the first output end of the transformer 309; the drain of the ninth switch tube 307 is electrically connected to the drain of the seventh switch tube 305; the source of the ninth switch tube 307 is electrically connected to the second output end of the transformer 309; the drain of the tenth switch tube 308 is electrically connected to the second output end of the transformer 309; and the source of the tenth switch tube 308 is electrically connected to the source of the eighth switch tube 306.

[0088] In the above scheme, switch tubes with directional flow are set on different bridge arms in the second bidirectional conversion circuit of the transformer 309, so that when the third switch tube 301 of the first bridge arm and the sixth switch tube 304 on the second bridge arm are turned on at the same time or the fourth switch tube 302 of the first bridge arm and the fifth switch tube 303 on the fourth bridge arm are turned on at the same time, if the seventh switch tube 305 and the tenth switch tube 308 in the second bidirectional conversion circuit are turned on at the same time or the eighth switch tube 306 and the ninth switch tube 307 are also in the on state, the current will flow from the first bidirectional conversion circuit through the transformer to the second bidirectional conversion circuit, thereby realizing bidirectional flow of energy.

[0089] In a certain implementation manner of this embodiment, in order to improve the efficiency of energy flowing bidirectionally in the voltage conversion circuit 102 , a third inductor and a fourth inductor may be provided in the voltage conversion circuit 102 .

[0090] Specifically, the inductor is connected to the switch tube, and the voltage conversion circuit 102 formed can be as follows: Figure 3 Wherein, the first end of the third inductor 310 is connected to the first input end of the transformer 309, and the second end of the third inductor 310 is connected to the primary side of the transformer 309; the first end of the fourth inductor 311 is connected to the first output end of the transformer 309, and the second end of the fourth inductor 311 is connected to the secondary side of the transformer.

[0091] The voltage conversion circuit 102 provided in the above scheme respectively sets inductance at both ends of the transformer 309 so that energy can be efficiently transmitted between the active bridges corresponding to the two ends of the transformer. At the same time, by adjusting the parameters of the inductance and the on-off state of the switch tube, precise control of the transmission power and the output voltage can be achieved, thereby improving the conversion effect.

[0092] In a certain implementation manner of this embodiment, when the voltage is transformed by the voltage conversion circuit 102 to send the transformed voltage to the DC input interface, in order to improve the effect of DC input and output, the following steps may be performed: Figure 1 The DC conversion device shown is provided with a filter circuit for filtering the second voltage outputted by the voltage conversion circuit 102 after voltage conversion, and outputting the filtered second voltage to the DC input interface.

[0093] Specifically, the filtering circuit is as follows: Figure 4As shown, it includes a first capacitor 401 and a fifth inductor 402; the first end of the first capacitor 401 is connected to the drain of the ninth switch tube 307; the second end of the first capacitor 401 is connected to the source of the tenth switch tube 308; the first end of the fifth inductor 402 is connected to the first end of the first capacitor 401; the second end of the fifth inductor 402 is connected to the DC input interface.

[0094] In the above scheme, the filter circuit is provided and capacitors and inductors are provided in the filter circuit to filter the DC input to be converted or the converted DC output to eliminate the AC in the DC input or DC output and improve the effect of DC conversion.

[0095] In a certain implementation manner of this embodiment, a plurality of eleventh switch tubes may be further provided in the DC conversion device. Specifically, the structure of the eleventh switch tube and the filter circuit is provided with reference to Figure 5 .like Figure 5 As shown, the drain of each of the eleventh switch tubes 501 is electrically connected to the second end of the fifth inductor 402; and the source of each of the eleventh switch tubes 501 is electrically connected to each of the DC input interfaces.

[0096] When the DC conversion device provided by the above scheme connects the bidirectional conversion circuit with multiple DC inputs and an external DC input interface, in order to improve the multiple DC inputs or multiple DC outputs of the DC conversion device, a switch tube may be set in the connection circuit between each DC input interface and the DC conversion device, and multiple outputs may be achieved by turning on the switch tube.

[0097] Further, referring to the power switching circuit shown in 2 and Figure 3 In the voltage conversion circuit shown, when constructing the DC conversion channel and the energy transmission channel, the controller 103 performs complementary control on the first switch tube 1011 and the second switch tube 1012, the controller 103 performs complementary control on the third switch tube 301 and the fourth switch tube 302, the controller 103 performs complementary control on the fifth switch tube 303 and the sixth switch tube 304, the controller 103 performs complementary control on the seventh switch tube 305 and the eighth switch tube 306, and the controller 103 performs complementary control on the ninth switch tube 307 and the tenth switch tube 308, so as to form a DC conversion channel. The complementary control is used to indicate that two complementary controlled switch tubes cannot be turned on or off at the same time.

[0098] Furthermore, when the controller 103 performs complementary control on the switch tubes on the same bridge arm in the voltage conversion circuit, in order to ensure that the voltage output by the transformer 309 meets the voltage required by the DC input interface, the controller 103 can control the power output by controlling the lagging phase between the corresponding switch tubes at both ends of the transformer 309.

[0099] In the above scheme, the controller 103 performs complementary control on different switch tubes on the same bridge arm, that is, it is used to indicate that two complementary controlled switch tubes cannot be turned on or off at the same time. For example, the third switch tube 301 and the fourth switch tube 302 cannot be turned on or off at the same time, and the fifth switch tube 303 and the sixth switch tube 304 cannot be turned on or off at the same time. In other words, the controller 103 can control different switch tubes not to be turned on or off at the same time to achieve a two-way flow of energy.

[0100] Furthermore, when the DC conversion device is connected to a plurality of DC input interfaces, the controller 103 realizes dual-path DC output by controlling the conduction state of the eleventh switch tube 501 connected to each of the DC input interfaces.

[0101] On the other hand, the embodiment of the present disclosure also provides a DC conversion method based on multi-source input, which is applicable to a power supply including a first power supply and a plurality of second power supplies; wherein the output end of the power supply is electrically connected to the input end of the voltage conversion circuit; the output end of the voltage conversion circuit is electrically connected to the DC input interface; wherein the specific process of the bidirectional conversion method is as follows Figure 6 See Figure 6 , the bidirectional transformation method includes steps 601 to 604.

[0102] Step 601: controlling the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface;

[0103] Step 602: In response to a power supply demand, connecting an energy transmission channel between the second power source and the DC conversion channel;

[0104] Step 603: controlling the voltage conversion circuit based on the DC conversion channel to obtain a first voltage of the first power supply, and controlling the voltage conversion circuit based on the energy transmission channel to obtain a second voltage of the second power supply;

[0105] Step 604: Use the first voltage and the second voltage as the output voltage of the power supply, and control the voltage conversion circuit to transform the output voltage to output the second voltage to the DC input interface.

[0106] In the embodiment of the present disclosure, when the second voltage obtained after the transformation is sent to the DC input interface, in order to further improve the effect of DC output, the DC output channel can be controlled to obtain the second voltage output by the voltage conversion circuit, and the DC output channel can be controlled to filter the obtained second voltage, and the filtered second voltage can be output to the DC input interface.

[0107] The present embodiment discloses a DC conversion method and device based on multi-source input. In the process of realizing multi-channel DC input, the voltage conversion circuit is first connected to the power supply and connected to the external DC input interface through the filter circuit, and then the voltage conversion and the bidirectional flow of energy are realized by controlling the conduction state of each switch tube in the voltage conversion circuit, thereby reducing the number of devices required for bidirectional energy flow. Furthermore, a power switching switch circuit is connected in series with the second power supply of each DC input of the additional multi-channel DC input in the power supply at the first end of the voltage conversion circuit, so that the additional DC input is connected in series to the original voltage conversion circuit through the conduction state of different switches in the power switching switch circuit, and then the conversion of multiple DC inputs is realized through one voltage conversion circuit, reducing the number of devices required for DC conversion, thereby reducing the complexity of the circuit. Furthermore, after the voltage is converted by the voltage conversion circuit, the voltage is filtered to improve the effect of voltage conversion.

[0108] Embodiment 2

[0109] The prior art often uses a DC-DC converter for DC conversion, but the existing DC-DC converter can only receive a single-channel DC input and perform unidirectional energy conversion. For situations where multiple DC inputs and outputs and bidirectional flow are required, multiple DC-DC converters need to be configured, which not only makes the circuit complex, but also causes a waste of resources. In this regard, the embodiment of the present disclosure takes a dual power supply system with dual DC input as an example, and discloses a DC conversion device based on multi-source input for the purpose of achieving dual output, so as to achieve dual DC input and dual output.

[0110] Specifically, the dual power supply system includes a first power supply and a second power supply, and a circuit structure diagram of a part of the circuit in the DC conversion device is connected to the dual power supply system for dual-path DC input and connected to external dual interfaces (including a first interface and a second interface) as shown in FIG. Figure 7 shown.

[0111] Furthermore, in order to realize dual-path DC input and output through the dual power supply system and the dual interface, a second power supply switching circuit for switching the working state of the second power supply, a dual active bridge converter for receiving the first voltage sent by the dual power supply system and transforming it, a boost filter circuit for filtering the voltage obtained after transformation, an interface switching circuit for switching the DC input interface, and a controller for controlling the second power supply switching circuit and the dual active bridge converter can be set in the DC conversion device.

[0112] like Figure 7 As shown, the second power supply switching circuit includes a switch tube Q5 and a switch tube Q6 and an inductor L8 and an inductor L9. The source of the switch tube Q5 is connected to the first end of the second power supply S2; the drain of the switch tube Q6 is connected to the first end of the second power supply S2; the drain of the switch tube Q5 is connected to the first end of the inductor L8; and the source of the switch tube Q6 is connected to the first end of the inductor L9.

[0113] like Figure 7 As shown, the dual active bridge converter includes switch tubes Q1 to Q3 and switch tubes Q7 to Q10, a transformer U1, and inductors L1 and L2.

[0114] The drain of the switch tube Q1 is connected to the first end of the first power source S1; the source of the switch tube Q1 is connected to the first end of the transformer U1; the second end of the inductor L8 is connected to the first end of the transformer U1;

[0115] The drain of the switch tube Q2 is connected to the first end of the transformer U1, and the source of the switch tube Q2 is connected to the second end of the second power source S2 and the second end of the first power source S1;

[0116] The drain of the switch tube Q3 is connected to the drain of the switch tube Q1, and the source of the switch tube Q3 is connected to the second end of the transformer U1;

[0117] The drain of the switch tube Q3 is connected to the second end of the transformer U1; the source of the switch tube Q3 is connected to the source of the switch tube Q2;

[0118] The first end of the inductor L1 is connected to the first end of the transformer U1, and the second end of the inductor L1 is connected to point 1 in the primary side of the transformer U1;

[0119] The first end of the inductor L2 is connected to the third end of the transformer U1 , and the second end of the inductor L2 is connected to the different-name terminal 3 corresponding to the point 1 in the secondary side of the transformer U1 .

[0120] The drain of the switch tube Q10 is connected to the drain of the switch tube Q8; the source of the switch tube Q10 is connected to the third end of the transformer U1;

[0121] The drain of the switch tube Q9 is connected to the third end of the transformer U1, and the source of the switch tube Q9 is connected to the source of the switch tube Q7;

[0122] The source of the switch tube Q8 is connected to the fourth end of the transformer U1 ; the drain of the switch tube Q7 is connected to the fourth end of the transformer U1 .

[0123] like Figure 7 As shown, the boost filter circuit includes a capacitor C1, an inductor L6, a capacitor C3 and an inductor L7.

[0124] Wherein, the first end of the capacitor C1 is connected to the drain of the switch tube Q8; the second end of the capacitor C1 is connected to the source of the switch tube Q7;

[0125] The first end of the inductor L6 is connected to the first end of the capacitor C1; the second end of the inductor L6 is connected to the first end of the capacitor C3;

[0126] The second end of the capacitor C3 is connected to the second end of the capacitor C1 ; the first end of the inductor L7 is connected to the first end of the capacitor C3 .

[0127] like Figure 7 As shown, the interface switching circuit includes a switch tube Q11 and a switch tube Q12.

[0128] The drain of the switch tube Q11 is electrically connected to the second end of the inductor L7; the source of the switch tube Q11 is connected to the first interface;

[0129] The drain of the switch tube Q12 is electrically connected to the drain of the switch tube Q11 ; the source of the switch tube Q12 is connected to the second interface.

[0130] Reference Figure 7 The DC conversion device with multiple DC inputs shown, when it is determined that the first power source S1 is inputting DC, first controls the switch tube Q5 to be turned on through the controller to connect the second power source S2 to the dual active bridge converter.

[0131] Next, in the dual active bridge converter, the conduction state of the switch tube can indeed determine the direction of current flow. Among them, the dual active bridge converter is composed of two full-bridge circuits (i.e., the H1 bridge composed of switch tubes Q1 to Q3 and the H2 bridge composed of switch tubes Q7 to Q10) connected through a high-frequency transformer and a resonant inductor. Each full-bridge circuit is composed of four switch tubes, and the midpoint voltage of the bridge arm can be independently controlled. By controlling the conduction and shutdown of the switch tube, the polarity and size of the midpoint voltage of the bridge arm can be changed, thereby controlling the flow direction and size of energy.

[0132] Further, when the energy flow direction in the dual-active bridge converter is forward energy transmission, when the switch tubes Q1 and Q3 of the H1 bridge are turned on at the same time by the controller (or Q2 and Q3 are turned on at the same time, but Q1 and Q3 are used as examples for explanation here), the midpoint voltage of the bridge arm of the H1 bridge is positive. At this time, if the switch tubes Q7 and Q10 (or Q8 and Q9) of the H2 bridge are also in the on state, the current will flow from the H1 bridge through the transformer to the H2 bridge, realizing forward energy transmission. The specific flow path of the current depends on the on state of the switch tube of the H2 bridge. For example, if Q1 and Q3 are turned on, the current will flow from the positive pole of the H1 bridge through Q1 and the transformer to the H2 bridge, and then return to the negative pole of the H1 bridge through Q7 and the load, forming a forward current loop.

[0133] When the energy flow direction in the dual active bridge converter is reverse energy transmission, the conduction states of the switches of the H1 bridge and the H2 bridge will be opposite, that is, the H1 bridge works as a rectifier, and the H2 bridge works as an inverter.

[0134] At this time, if the switch tubes Q7 and Q10 of the H2 bridge are turned on (or Q8 and Q9 are turned on), the midpoint voltage of the bridge arm of the H2 bridge is positive. The current will flow from the H2 bridge through the transformer to the H1 bridge, realizing reverse energy transmission. At this time, the specific flow path of the current also depends on the conduction state of the switch tube. For example, if Q7 and Q10 are turned on, the current will flow from the positive pole of the H2 bridge through Q7 and the transformer to the H1 bridge, and then return to the negative pole of the H2 bridge through the anti-parallel diode of Q1 and the load, forming a reverse current loop.

[0135] In practical applications, in order to achieve soft switching and reduce switching losses, the switch tube usually has a certain dead time when it is turned on and off. During the dead time, the switch tube is in the off state, but the current may continue to flow through the anti-parallel diode. Usually, a phase shift control strategy is used to adjust the transmission power and output voltage. By changing the phase difference of the switch tube, the direction and size of energy transmission can be controlled.

[0136] In summary, by controlling the conduction state of the switch tube in the dual active bridge converter, the conduction direction and magnitude of the current can be accurately controlled to achieve efficient, bidirectional transmission of energy.

[0137] A DC conversion device based on multi-source input disclosed in this embodiment can realize three modes of energy transmission from the first power supply S1 to the first interface or / and the second interface, from the second power supply S2 to the first interface or / and the second interface, and from the first power supply S1 and the second power supply S2 to the first interface or / and the second interface. The control method is simple and basically the same as the general dual active bridge. First, the duty cycle of the switch signals of switches Q1, 2, 3, 3, 7, 8, 9 and 10 is constant at 50%, ensuring that the switch signals of the upper and lower switch tubes of the same bridge arm are complementary.

[0138] Furthermore, the circuit disclosed in this embodiment has various and flexible usage scenarios. The first power supply S1 and the second power supply S2 can be replaced by photovoltaic panels. At the same time, based on the connection method of the second power supply S2, a third power supply, a fourth power supply, etc. can be added. That is, the connection method of the third power supply and the fourth power supply is the same as the connection method of the second power supply S2 (in parallel). In addition, a switch can also be added to the output end to achieve three-way output, four-way output, etc., and then power conversion can be performed between multiple inputs and multiple outputs without transformer isolation. It can be used to replace the three-winding transformer in the traditional multi-port converter.

[0139] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A DC conversion method based on multi-source input, characterized in that: Applicable to a power supply including a first power supply and a second power supply; wherein the output end of the power supply is electrically connected to the input end of a voltage conversion circuit; the output end of the voltage conversion circuit is electrically connected to a DC input interface; the DC conversion method comprises: Controlling the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface; In response to a power supply demand, connecting an energy transmission channel between the second power supply and the DC conversion channel; Controlling the voltage conversion circuit based on the DC conversion channel to obtain a first voltage of the first power supply, and controlling the voltage conversion circuit based on the energy transmission channel to obtain a second voltage of the second power supply; The first voltage and the second voltage are used as the output voltage of the power supply, and the voltage conversion circuit is controlled to transform the output voltage so as to output the second voltage to the DC input interface.

2. A DC conversion method based on multi-source input according to claim 1, characterized in that: The step of constructing a DC output channel between the output end and the DC input interface, and outputting the second voltage to the DC input interface based on the DC output channel, further includes: Controlling the DC output channel to obtain a second voltage output by the voltage conversion circuit; The DC output channel is controlled to filter the acquired second voltage, and the filtered second voltage is output to the DC input interface.

3. A DC conversion device based on multi-source input, suitable for a power supply including a first power supply and a second power supply, characterized in that: The DC conversion device includes a controller, a voltage conversion circuit and a power supply switching circuit; The first end of the power switching circuit is electrically connected to the first end of the second power supply; the second end of the power switching circuit and the first end of the first power supply are electrically connected to the first end of the voltage conversion circuit respectively; the second end of the voltage conversion circuit is electrically connected to the DC input interface; The voltage conversion circuit is connected to the controller signal so that the controller controls the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface; The power switching circuit is connected to the controller signal so that the controller controls the power switching circuit to connect the energy transmission channel between the second power source and the DC conversion channel; The controller controls the voltage conversion circuit to obtain the first voltage of the first power supply based on the DC conversion channel, and controls the voltage conversion circuit to obtain the second voltage of the second power supply based on the energy transmission channel, and uses the first voltage and the second voltage as the output voltage of the power supply to control the voltage conversion circuit to transform the output voltage and output the second voltage to the DC input interface.

4. A DC conversion device based on multi-source input according to claim 3, characterized in that: The power switching circuit includes a first switch tube and a second switch tube; Wherein, the source of the first switch tube is connected to the first end of the second power supply; the drain of the first switch tube is connected to the first input end of the voltage conversion circuit; The drain of the second switch tube is connected to the first end of the second power supply, and the source of the second switch tube is connected to the second input end of the voltage conversion circuit; wherein the first end of the voltage conversion circuit includes a first input end and a second input end.

5. A DC conversion device based on multi-source input according to claim 4, characterized in that: The power switching circuit also includes a first inductor and a second inductor; Wherein, the first end of the first inductor is connected to the drain of the first switch tube; the second end of the first inductor is connected to the first input end of the voltage conversion circuit; The first end of the second inductor is connected to the source of the second switch tube; the second end of the second inductor is connected to the second input end of the voltage conversion circuit.

6. A DC conversion device based on multi-source input according to claim 5, characterized in that: The voltage conversion circuit includes a transformer, a third switch tube, a fourth switch tube, a fifth switch tube, a sixth switch tube, a seventh switch tube, an eighth switch tube, a ninth switch tube and a tenth switch tube; Wherein, the drain of the third switch tube is electrically connected to the discharge end of the first power supply; the source of the third switch tube is electrically connected to the first input end of the transformer; The drain of the fourth switch tube is electrically connected to the first input terminal of the transformer; the source of the fourth switch tube is electrically connected to the charging terminal of the first power supply; the source of the fourth switch tube is electrically connected to the charging terminal of the second power supply; wherein the first terminal of the first power supply includes the discharging terminal and the charging terminal; the charging terminal of the second power supply is the second terminal of the second power supply; The drain of the fifth switch tube is electrically connected to the drain of the third switch tube; the source of the fifth switch tube is electrically connected to the second input terminal of the transformer; The drain of the sixth switch tube is electrically connected to the second input end of the transformer; the source of the sixth switch tube is electrically connected to the source of the fourth switch tube. The source of the seventh switch tube is electrically connected to the first output terminal of the transformer; the drain of the eighth switch tube is electrically connected to the first output terminal of the transformer; The drain of the ninth switch tube is electrically connected to the drain of the seventh switch tube; the source of the ninth switch tube is electrically connected to the second output end of the transformer; The drain of the tenth switch tube is electrically connected to the second output end of the transformer; the source of the tenth switch tube is electrically connected to the source of the eighth switch tube.

7. A DC conversion device based on multi-source input according to any one of claim 6, characterized in that: The voltage conversion circuit also includes a third inductor and a fourth inductor; Wherein, the first end of the third inductor is connected to the first input end of the transformer, and the second end of the third inductor is connected to the primary side of the transformer; A first end of the fourth inductor is connected to the first output end of the transformer, and a second end of the fourth inductor is connected to the secondary side of the transformer.

8. The DC conversion device based on multi-source input according to claim 6, characterized in that: It also includes a filter circuit, which is used to filter the second voltage output by the voltage conversion circuit and output the filtered second voltage to the DC input interface; Wherein, the filtering circuit includes a first capacitor and a fifth inductor; the first end of the first capacitor is connected to the drain of the ninth switch tube; the second end of the first capacitor is connected to the source of the tenth switch tube; The first end of the fifth inductor is connected to the first end of the first capacitor; the second end of the fifth inductor is connected to the DC input interface.

9. A DC conversion device based on multi-source input according to claim 8, characterized in that: It also includes a plurality of eleventh switching tubes; wherein the drain of each of the eleventh switching tubes is electrically connected to the second end of the fifth inductor; and the source of each of the eleventh switching tubes is electrically connected to each of the DC input interfaces.

10. A DC conversion device based on multi-source input according to claim 6, characterized in that: The controller controls the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface, including: The controller performs complementary control on the switch tubes in the voltage conversion circuit to construct a DC conversion channel between the first power supply and the DC input interface; wherein the complementary control is used to control the two switch tubes on the same bridge arm so that they cannot be turned on or off at the same time.

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