DCDC conversion circuit, DC charging pile and energy storage system

Abstract

The invention provides a DCDC conversion circuit, a DC charging pile and an energy storage system, and relates to the technical field of electric power. The DCDC conversion circuit comprises at least two conversion branches including a first conversion branch and a second conversion branch, and the first conversion branch and the second conversion branch are connected in parallel; a primary side coil of the coupling transformer is connected in series with the first conversion branch, and a secondary side coil of the coupling transformer is connected in series with the second conversion branch; wherein the turn ratio of the primary side coil of the coupling transformer to the secondary side coil of the coupling transformer is 1. According to the embodiment of the invention, through the magnetic coupling transformer, the current in the two or more parallel conversion branches can be ensured to be consistent, so that the problem of system instability caused by triggering current protection or high-temperature protection due to the fact that the single-path current or power is remarkably too high is avoided, and the equipment reliability is improved.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a DCDC conversion circuit, a DC charging pile and an energy storage system. Background Art

[0002] In the related technology, DCDC (DC-to-DC) converters are widely used in the field of new energy vehicles and battery energy storage. For example, in order to match different models and meet the needs of fast and efficient charging, the input and output voltage range of a bidirectional car charging power supply is generally 150V to 1000V, and the output power of a single charging module reaches 30kW to 40kW. With the increase in power and the expansion of the voltage range, the implementation of a single bidirectional power supply becomes difficult and complicated, with low efficiency, concentrated heat sources and difficult thermal design. In order to better achieve a bidirectional wide voltage range and high power output, while considering the feasibility of heat dissipation, two bidirectional DCDCs are generally connected in parallel to achieve the function.

[0003] When two bidirectional DCDCs are connected in parallel, it is necessary to consider whether the two channels have equal current and power. In theory, as long as the electrical parameters of the two channels are the same, the current will be equalized and the power of the two channels will be basically the same. However, in actual use, due to the influence of PCB (Printed circuit board) routing and parasitic parameters, as well as the deviation of the parameters of the electronic components used in the actual circuit, the two bidirectional DCDCs in parallel will cause output power deviation during actual output, which will cause one channel to trigger overcurrent protection, or one channel to heat up severely and trigger overtemperature protection, resulting in system instability and affecting equipment reliability. Summary of the invention

[0004] The present application aims to at least solve the problem of system instability and poor equipment reliability caused by parameter deviation of dual-channel DCDC parallel connection in the prior art or related art.

[0005] To this end, a first aspect of the present application proposes a DCDC conversion circuit.

[0006] A second aspect of the present application provides a DC charging pile.

[0007] A third aspect of the present application provides an energy storage system.

[0008] In view of this, the first aspect of the present application provides a DCDC conversion circuit, the DCDC conversion circuit comprising: at least two conversion branches, including a first conversion branch and a second conversion branch, the first conversion branch and the second conversion branch are connected in parallel; a coupling transformer, the primary coil of the coupling transformer is connected in series to the first conversion branch, and the secondary coil of the coupling transformer is connected in series to the second conversion branch; wherein the turns ratio of the primary coil of the coupling transformer to the secondary coil of the coupling transformer is 1.

[0009] In this technical solution, the DCDC conversion circuit includes two or more parallel conversion branches. Through the parallel multi-channel conversion branches, the DCDC conversion circuit can increase the power and widen the voltage range while ensuring efficiency and solving problems such as heat source concentration.

[0010] Take the DCDC conversion circuit including two parallel conversion branches, specifically the first conversion branch and the second conversion branch, as an example. Under ideal conditions, as long as the electrical parameters of the first conversion branch and the second conversion branch are consistent, the power of the first conversion branch and the second conversion branch can be guaranteed to be consistent during operation. However, in actual application scenarios, due to PCB routing, parasitic parameters, electronic component process factors and other factors, there will be a certain deviation in the electrical parameters of the two conversion branches of the same specification, which will eventually lead to unequal power of the two branches, which may cause one of them to be too high, triggering overcurrent protection or high temperature protection, affecting system stability.

[0011] In response to the above problems, the present application sets a coupling transformer between two conversion branches, that is, the first conversion branch and the second conversion branch, and makes the current flowing through the two conversion branches consistent through the coupling transformer. The coupling transformer has high coupling purity, and the current magnitudes in the two parallel branches are consistent by closing the magnetic flux to zero. At the same time, the above magnetic coupling process is carried out in every switching cycle, so the response speed is very fast, which can reach the nanosecond level, making the bidirectional current sharing effect significant.

[0012] Among them, the coupling transformer includes a primary coil and a secondary coil, the primary coil is connected in series to the first conversion branch, and the secondary coil is connected in series to the second conversion branch. The turns ratio of the primary coil of the coupling transformer and the secondary coil of the coupling transformer is 1. Therefore, when the current flowing through the primary coil of the first conversion branch is equal to the current flowing through the secondary coil of the second conversion branch, the coupling transformer is in a balanced state.

[0013] When the current of one of the conversion branches changes, for example, when the current of the first conversion branch flowing through the primary coil of the coupling transformer changes, a changing magnetic field will be generated around the primary coil of the coupling transformer. This changing magnetic field will be induced to the adjacent secondary coil, generating an induced electromotive force in the secondary coil. If the secondary coil is closed, an induced current will be generated. Since the turns ratio of the primary coil and the secondary coil of the coupling transformer is 1, the induced current generated will be equal, so that the current of the secondary coil is equal to that of the primary coil, which ensures that the current and power of the first conversion branch and the second conversion branch in parallel are equal.

[0014] The embodiment of the present application uses a magnetically coupled transformer to ensure that the currents in two or more parallel conversion branches are consistent, thereby avoiding the problem of system instability caused by triggering current protection or high temperature protection due to significantly excessive current or power in a single circuit, thereby improving equipment reliability.

[0015] In addition, the DCDC conversion circuit in the above technical solution provided by the present application may also have the following additional technical features:

[0016] In some technical solutions of the present application, optionally, the conversion branch includes: a primary circuit, which is electrically connected to an input source; a secondary circuit, which is electrically connected to an output source; a high-frequency transformer, whose primary coil is electrically connected to the primary circuit, and whose secondary coil is electrically connected to the secondary circuit.

[0017] In this technical solution, a conversion branch includes a primary circuit, a secondary circuit and a high-frequency transformer. The primary circuit and the secondary circuit are electrically connected through the high-frequency transformer, thereby realizing dynamic adjustment of output power and output voltage.

[0018] Exemplarily, the primary circuit of the conversion branch is connected to the input source. When the first conversion branch and the second conversion branch are connected in parallel, the input source of the first conversion branch and the input source of the second conversion branch can be connected in series, in parallel, or independent of each other.

[0019] The secondary circuit of the conversion branch is connected to the output source. When the first conversion branch and the second conversion branch are connected in parallel, the output source of the first conversion branch and the output source of the second conversion branch can be connected in series, in parallel, or independent of each other.

[0020] In some technical solutions of the present application, optionally, the first conversion branch includes a first primary circuit and a first secondary circuit, and the second conversion branch includes a second primary circuit and a second secondary circuit; wherein the primary coil of the coupling transformer is electrically connected to the first primary circuit, and the secondary coil of the coupling transformer is electrically connected to the second primary circuit; or, the primary coil of the coupling transformer is electrically connected to the first secondary circuit, and the secondary coil of the coupling transformer is electrically connected to the second secondary circuit.

[0021] In this technical solution, the coupling transformer can be respectively connected to the primary circuits of the two parallel conversion branches, and can also be respectively connected to the secondary circuits of the two parallel conversion branches.

[0022] Exemplarily, the first conversion branch includes a first primary circuit, the second conversion branch includes a second primary circuit, and the primary coil and the secondary coil of the coupling transformer are connected to the first primary circuit and the second primary circuit respectively.

[0023] Exemplarily, the first conversion branch includes a first secondary circuit, the second conversion branch includes a second secondary circuit, and the primary coil and the secondary coil of the coupling transformer are connected to the first secondary circuit and the second secondary circuit respectively.

[0024] In some technical solutions of the present application, optionally, the conversion branch also includes: an intermediate conversion circuit, the primary circuit is electrically connected to the primary coil of the high-frequency transformer through an intermediate conversion circuit, and the secondary circuit is electrically connected to the secondary coil of the high-frequency transformer through an intermediate conversion circuit.

[0025] In this technical solution, one conversion branch includes two intermediate conversion circuits, wherein, on the primary side of the conversion branch, the primary circuit is connected to the primary coil of the high-frequency transformer through an intermediate conversion circuit. On the secondary side of the conversion branch, the secondary circuit is connected to the secondary coil of the high-frequency transformer through another intermediate conversion circuit.

[0026] By setting up an intermediate conversion circuit, it is possible to adjust the working mode and working mode of the conversion branch, and at the same time prevent the magnetic saturation of the high-frequency transformer.

[0027] In some technical solutions of the present application, optionally, the first conversion branch includes a first intermediate conversion circuit and a second intermediate conversion circuit, and the high-frequency transformer includes a first high-frequency transformer and a second high-frequency transformer; the first intermediate conversion circuit is connected between the first primary circuit and the primary coil of the first high-frequency transformer, and the second intermediate conversion circuit is connected between the first secondary circuit and the secondary coil of the first high-frequency transformer; the second conversion branch includes a third intermediate conversion circuit and a fourth intermediate conversion circuit, the third intermediate conversion circuit is connected between the second primary circuit and the primary coil of the second high-frequency transformer, and the fourth intermediate conversion circuit is connected between the second secondary circuit and the secondary coil of the second high-frequency transformer; wherein the primary coil of the coupling transformer is electrically connected to the first intermediate conversion circuit, and the secondary coil of the coupling transformer is electrically connected to the third intermediate conversion circuit; or, the primary coil of the coupling transformer is electrically connected to the second intermediate conversion circuit, and the secondary coil of the coupling transformer is electrically connected to the fourth intermediate conversion circuit.

[0028] In this technical solution, the first conversion branch and the second conversion branch are connected in parallel, wherein the first conversion branch includes a first intermediate conversion circuit located on the primary side and a second intermediate conversion circuit located on the secondary side. The second conversion branch includes a third intermediate conversion circuit located on the primary side and a fourth intermediate conversion circuit located on the secondary side.

[0029] The high-frequency transformer specifically includes a first high-frequency transformer and a second high-frequency transformer, the first intermediate conversion circuit is connected between the first primary circuit and the primary coil of the first high-frequency transformer, and the second intermediate conversion circuit is connected between the first secondary circuit and the secondary coil of the first high-frequency transformer. The second conversion branch includes a third intermediate conversion circuit and a fourth intermediate conversion circuit, the third intermediate conversion circuit is connected between the second primary circuit and the primary coil of the second high-frequency transformer, and the fourth intermediate conversion circuit is connected between the second secondary circuit and the secondary coil of the second high-frequency transformer. In one case, the primary coil and the secondary coil of the coupling transformer are electrically connected to the intermediate conversion circuits on the primary side of the first conversion branch and the second conversion branch, respectively. Exemplarily, the primary coil of the coupling transformer is electrically connected to the positive line of the first intermediate conversion circuit, and the secondary coil of the coupling transformer is electrically connected to the negative line of the third intermediate conversion circuit. At this time, the current values ​​of the primary coil and the secondary coil of the coupling transformer are equal, and the current directions are opposite.

[0030] In another case, the primary coil and the secondary coil of the coupling transformer are electrically connected to the intermediate conversion circuits on the secondary sides of the first conversion branch and the second conversion branch, respectively. Exemplarily, the primary coil of the coupling transformer is electrically connected to the positive line of the second intermediate conversion circuit, and the secondary coil of the coupling transformer is electrically connected to the negative line of the fourth intermediate conversion circuit. At this time, the current values ​​of the primary coil and the secondary coil of the coupling transformer are equal, and the current directions are opposite.

[0031] By arranging two coils of the coupling transformer to be respectively connected to the primary side of the parallel conversion branch, or respectively connected to the secondary side of the parallel conversion branch, the currents of the two conversion branches can be kept consistent, thereby improving the system stability.

[0032] In some technical solutions of the present application, optionally, the intermediate conversion circuit includes: a first capacitor; a first inductor, a first end of the first inductor is electrically connected to the first capacitor, and a second end of the first inductor is electrically connected to the high-frequency transformer.

[0033] In this technical solution, the intermediate conversion circuit includes a first capacitor and a first inductor connected in series, wherein one end of the first inductor is connected to the first capacitor and the other end is electrically connected to the high-frequency transformer. That is, the first inductor is located between the first capacitor and the high-frequency transformer.

[0034] In some technical solutions of the present application, optionally, the intermediate conversion circuit includes: a second capacitor, the second capacitor is connected in series between the primary circuit and the high-frequency transformer; or, the second capacitor is connected in series between the secondary circuit and the high-frequency transformer.

[0035] In this technical solution, the intermediate conversion circuit includes a second capacitor, and the second capacitor is located between the primary circuit and the high-frequency transformer, or between the secondary circuit and the high-frequency transformer.

[0036] Exemplarily, the circuit structures of the intermediate conversion circuit between the primary circuit and the high-frequency transformer and the intermediate conversion circuit between the secondary circuit and the high-frequency transformer may be the same or different. For example, the intermediate conversion circuit between the primary circuit and the high-frequency transformer includes a first capacitor and a first inductor connected in series, and the intermediate conversion circuit between the secondary circuit and the high-frequency transformer includes a second capacitor. For example, the intermediate conversion circuit between the primary circuit and the high-frequency transformer includes a first capacitor and a first inductor connected in series, and the intermediate conversion circuit between the secondary circuit and the high-frequency transformer also includes a first capacitor and a first inductor connected in series.

[0037] In some technical solutions of the present application, optionally, the primary circuit includes a first bridge circuit, and the secondary circuit includes a second bridge circuit; wherein the first bridge circuit is a half-bridge rectifier circuit or a full-bridge rectifier circuit; and the second bridge circuit is a half-bridge rectifier circuit or a full-bridge rectifier circuit.

[0038] In this technical solution, both the primary circuit and the secondary circuit are bridge circuits, wherein the primary circuit includes a first bridge circuit, the secondary circuit includes a second bridge circuit, and the first bridge circuit and the second bridge circuit can both be full-bridge rectifier circuits or half-bridge rectifier circuits.

[0039] Exemplarily, the first bridge circuit is a full-bridge rectifier circuit, and the second bridge circuit is a full-bridge rectifier circuit.

[0040] Exemplarily, the first bridge circuit is a half-bridge rectifier circuit, and the second bridge circuit is a half-bridge rectifier circuit.

[0041] Exemplarily, the first bridge circuit is a full-bridge rectifier circuit, and the second bridge circuit is a half-bridge rectifier circuit.

[0042] Exemplarily, the first bridge circuit is a half-bridge rectifier circuit, and the second bridge circuit is a full-bridge rectifier circuit.

[0043] The working modes of the first bridge circuit and the second bridge circuit can be the same or different. In the two parallel conversion branches, the working modes of the bridge circuits located on the primary side are the same. For example, the first bridge circuit in the first conversion branch is defined as bridge circuit 1, the second bridge circuit in the first conversion branch is defined as bridge circuit 2, the first bridge circuit in the second conversion branch is defined as bridge circuit 3, and the second bridge circuit in the second conversion branch is defined as bridge circuit 4.

[0044] Then the working modes of bridge circuit 1 and bridge circuit 3 are the same, and the working modes of bridge circuit 2 and bridge circuit 4 are the same.

[0045] The working modes of the bridge circuit include frequency modulation, duty cycle modulation, phase shift or fixed frequency duty cycle mode.

[0046] In some technical solutions of the present application, optionally, the primary circuit includes a third capacitor, and the first bridge circuit is connected to the input source through the third capacitor; the secondary circuit includes a fourth capacitor, and the second bridge circuit is connected to the output source through the fourth capacitor.

[0047] In this technical solution, the primary circuit includes a third capacitor, which is connected in parallel with the input source. The third capacitor can buffer the energy of the input source and absorb the high-frequency spikes generated by the load fluctuation of the line of the primary circuit. The fourth capacitor is connected in parallel with the output source. The fourth capacitor can buffer the energy of the output source and absorb the high-frequency spikes generated by the load fluctuation of the line of the secondary circuit.

[0048] The second aspect of the present application provides a DC charging pile, including: a charging gun, the charging gun is used to connect to an electric vehicle; a DCDC conversion circuit as provided in any of the above technical solutions, the first end of the DCDC conversion circuit is connected to the energy storage power supply system, and the second end is connected to the charging gun. Therefore, the DC charging pile also includes the same technical effects, and to avoid repetition, it will not be repeated here.

[0049] In some technical solutions of the present application, optionally, the DCDC conversion circuit is configured so that when the energy storage power supply system charges the electric vehicle, the power direction of the DCDC conversion circuit flows from the first end to the second end; when the electric vehicle charges the energy storage power supply system, the power direction of the DCDC conversion circuit flows from the second end to the first end.

[0050] In this technical solution, when the DC charging pile is connected to the electric vehicle, in one case, the power of the DCDC conversion circuit flows from the first end to the second end, and the electric vehicle is charged by the energy storage power supply system. In another case, the power of the DCDC conversion circuit flows from the second end to the first end, and the electric vehicle charges the energy storage power supply system, thereby realizing bidirectional charging.

[0051] The third aspect of the present application provides an energy storage system, including: at least one battery pack, at least one battery pack is used to store electrical energy or output electrical energy; a DC charging pile, the DC charging pile integrates a DCDC conversion circuit as provided in any of the above technical solutions, and therefore also includes the same technical effects, which will not be repeated here to avoid repetition. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0053] Figure 1A A circuit schematic diagram of a DCDC conversion circuit of some embodiments of the present application is shown;

[0054] Figure 1BA circuit schematic diagram of a DCDC conversion circuit of some embodiments of the present application is shown;

[0055] Figure 2 A circuit diagram of a DCDC conversion circuit according to some embodiments of the present application is shown;

[0056] Figure 3 A circuit diagram of a DCDC conversion circuit according to some embodiments of the present application is shown;

[0057] Figure 4 A circuit diagram of a DCDC conversion circuit according to some embodiments of the present application is shown;

[0058] Figure 5 A schematic diagram showing the structure of an intermediate conversion circuit in some embodiments of the present application is shown;

[0059] Figure 6 A schematic diagram showing the structure of an intermediate conversion circuit in some embodiments of the present application is shown;

[0060] Figure 7 A schematic diagram showing the structure of a bridge circuit in some embodiments of the present application is shown;

[0061] Figure 8 A schematic structural diagram of a bridge circuit according to some embodiments of the present application is shown.

[0062] Reference numerals:

[0063] 100DCDC conversion circuit, 102 conversion branch, 1021 first conversion branch, 1022 second conversion branch, 1023 primary circuit, 10231 first primary circuit, 10232 second primary circuit, 1024 secondary circuit, 10241 first secondary circuit, 10242 second secondary circuit, 104 intermediate conversion circuit, 1042 first intermediate conversion circuit, 1044 second intermediate conversion circuit, 1046 third intermediate conversion circuit, 1048 fourth intermediate conversion circuit, 106 first bridge circuit, 108 second bridge circuit;

[0064] V1 input source, V2 output source, T high frequency transformer, T1 first high frequency transformer, T2 second high frequency transformer, T3 coupling transformer, C1 first capacitor, L1 first inductor, C2 second capacitor, C3 third capacitor, C4 fourth capacitor. DETAILED DESCRIPTION

[0065] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0066] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0067] Refer to the following Figures 1A to 8 The present invention describes a DCDC conversion circuit, a DC charging pile and an energy storage system according to some embodiments of the present application.

[0068] In some embodiments of the present application, a DCDC conversion circuit is provided. Figure 1A and Figure 1B A circuit diagram of a DCDC conversion circuit of some embodiments of the present application is shown. Figure 2 , Figure 3 and Figure 4 The circuit diagram of the DCDC conversion circuit of some embodiments of the present application is shown as follows: Figure 1A , Figure 1B , Figure 2 , Figure 3 and Figure 4 As shown, the DCDC conversion circuit 100 includes: at least two conversion branches 102, including a first conversion branch 1021 and a second conversion branch 1022, the first conversion branch 1021 and the second conversion branch 1022 are connected in parallel; a coupling transformer T3, the primary coil of the coupling transformer T3 is connected in series to the first conversion branch 1021, and the secondary coil of the coupling transformer T3 is connected in series to the second conversion branch 1022; wherein the turns ratio of the primary coil of the coupling transformer T3 to the secondary coil of the coupling transformer T3 is 1.

[0069] In this embodiment, the DCDC conversion circuit 100 includes two or more parallel conversion branches 102. Through the parallel multi-way conversion branches 102, the DCDC conversion circuit 100 can increase the power and widen the voltage range while ensuring efficiency and solving problems such as heat source concentration.

[0070] Taking the DCDC conversion circuit 100 including two parallel conversion branches 102, specifically the first conversion branch 1021 and the second conversion branch 1022 as an example, in an ideal state, as long as the electrical parameters of the first conversion branch 1021 and the second conversion branch 1022 are consistent, it can ensure that the power of the first conversion branch 1021 and the second conversion branch 1022 is consistent during operation. In actual application scenarios, due to PCB routing, parasitic parameters, electronic component process factors and other reasons, there will be a certain deviation in the electrical parameters of the two conversion branches 102 of the same specification, which will eventually lead to unequal power of the two branches, which may cause one of them to be too high, triggering overcurrent protection or high temperature protection, affecting system stability.

[0071] In view of the above problems, the present application sets a coupling transformer T3 between the two conversion branches 102, that is, the first conversion branch 1021 and the second conversion branch 1022, so that the current flowing through the two conversion branches 102 is consistent through the coupling transformer T3. The coupling purity of the coupling transformer T3 is high, and the current magnitudes in the two parallel branches are consistent by closing the magnetic flux to zero. At the same time, the above magnetic coupling process is carried out in each switching cycle, so the response speed is very fast, which can reach the nanosecond level, so that the bidirectional current sharing effect is significant.

[0072] Among them, the coupling transformer T3 includes a primary coil and a secondary coil, the primary coil is connected in series to the first conversion branch 1021, and the secondary coil is connected in series to the second conversion branch 1022. The turns ratio of the primary coil of the coupling transformer T3 and the secondary coil of the coupling transformer T3 is 1. Therefore, when the current flowing through the primary coil of the first conversion branch 1021 is equal to the current flowing through the secondary coil of the second conversion branch 1022, the coupling transformer T3 is in a balanced state.

[0073] When the current of one of the conversion branches 102 changes, for example, when the current of the first conversion branch flowing through the primary coil of the coupling transformer T3 changes, a changing magnetic field will be generated around the primary coil of the coupling transformer T3, and this changing magnetic field will be induced to the adjacent secondary coil, generating an induced electromotive force in the secondary coil. If the secondary coil is closed, an induced current will be generated. Since the turns ratio of the primary coil and the secondary coil of the coupling transformer T3 is 1, the generated induced current will be equal, so that the current of the secondary coil is equal to that of the primary coil, which ensures that the current and power of the first conversion branch 1021 and the second conversion branch 1022 connected in parallel are equal.

[0074] The embodiment of the present application uses the magnetic coupling transformer T3 to ensure that the currents in two or more parallel conversion branches 102 are consistent, thereby avoiding the problem of system instability caused by triggering current protection or high temperature protection due to significantly excessive single-circuit current or power, thereby improving equipment reliability.

[0075] In some embodiments of the present application, optionally, Figure 1A , Figure 1B , Figure 2 , Figure 3 and Figure 4 As shown, the conversion branch 102 includes: a primary circuit 1023, which is electrically connected to the input source V1; a secondary circuit 1024, which is electrically connected to the output source V2; a high-frequency transformer T, whose primary coil is electrically connected to the primary circuit 1023, and whose secondary coil is electrically connected to the secondary circuit 1024.

[0076] In this embodiment, a conversion branch 102 includes a primary circuit 1023, a secondary circuit 1024 and a high-frequency transformer T. The primary circuit 1023 and the secondary circuit 1024 are electrically connected through the high-frequency transformer T, thereby realizing dynamic adjustment of output power and output voltage.

[0077] Exemplarily, the primary circuit 1023 of the conversion branch 102 is connected to the input source V1. When the first conversion branch 1021 and the second conversion branch 1022 are connected in parallel, the input source V1 of the first conversion branch 1021 and the input source V1 of the second conversion branch 1022 can be connected in series, in parallel, or independent of each other.

[0078] The secondary circuit 1024 of the conversion branch 102 is connected to the output source V2. When the first conversion branch 1021 and the second conversion branch 1022 are connected in parallel, the output source V2 of the first conversion branch 1021 and the output source V2 of the second conversion branch 1022 can be connected in series, in parallel, or independent of each other.

[0079] In some embodiments of the present application, optionally, Figure 1A , Figure 1B , Figure 2 , Figure 3 and Figure 4 As shown, the first conversion branch 1021 includes a first primary circuit 10231 and a first secondary circuit 10241, and the second conversion branch 1022 includes a second primary circuit 10232 and a second secondary circuit 10242; wherein, the primary coil of the coupling transformer T3 is electrically connected to the first primary circuit 10231, and the secondary coil of the coupling transformer T3 is electrically connected to the second primary circuit 10232; or, the primary coil of the coupling transformer T3 is electrically connected to the first secondary circuit 10241, and the secondary coil of the coupling transformer T3 is electrically connected to the second secondary circuit 10242.

[0080] In this embodiment, the coupling transformer T3 may be respectively connected to the primary circuits 1023 of the two parallel conversion branches 102 , or may be respectively connected to the secondary circuits 1024 of the two parallel conversion branches 102 .

[0081] For example, Figure 1A As shown, the first conversion branch 1021 includes a first primary circuit 10231, the second conversion branch 1022 includes a second primary circuit 10232, and the primary coil and the secondary coil of the coupling transformer T3 are connected to the first primary circuit 10231 and the second primary circuit 10232 respectively.

[0082] For example, Figure 1BAs shown, the first conversion branch 1021 includes a first secondary circuit 10241, the second conversion branch 1022 includes a second secondary circuit 10242, and the primary coil and the secondary coil of the coupling transformer T3 are connected to the first secondary circuit 10241 and the second secondary circuit 10242 respectively.

[0083] In some embodiments of the present application, optionally, Figure 1A , Figure 1B , Figure 2 , Figure 3 and Figure 4 As shown, the conversion branch 102 also includes: an intermediate conversion circuit 104, the primary circuit 1023 is electrically connected to the primary coil of the high-frequency transformer T through an intermediate conversion circuit 104, and the secondary circuit 1024 is electrically connected to the secondary coil of the high-frequency transformer T through an intermediate conversion circuit 104.

[0084] In this embodiment, one conversion branch 102 includes two intermediate conversion circuits, wherein, on the primary side of the conversion branch 102, the primary circuit 1023 is connected to the primary coil of the high-frequency transformer T through an intermediate conversion circuit 104. On the secondary side of the conversion branch 102, the secondary circuit 1024 is connected to the secondary coil of the high-frequency transformer T through another intermediate conversion circuit 104.

[0085] By setting the intermediate conversion circuit, the working mode and working mode of the conversion branch 102 can be adjusted, and at the same time, the magnetic saturation of the high-frequency transformer T can be prevented.

[0086] In some embodiments of the present application, optionally, Figure 1A , Figure 1B , Figure 2 , Figure 3 and Figure 4As shown, the first conversion branch 1021 includes a first intermediate conversion circuit 1042 and a second intermediate conversion circuit 1044, and the high-frequency transformer T includes a first high-frequency transformer T1 and a second high-frequency transformer T2; the first intermediate conversion circuit 1042 is connected between the first primary circuit 10231 and the primary coil of the first high-frequency transformer T1, and the second intermediate conversion circuit 1044 is connected between the first secondary circuit 10241 and the secondary coil of the first high-frequency transformer T1; the second conversion branch 1022 includes a third intermediate conversion circuit 1046 and a fourth intermediate conversion circuit 1048, and the third intermediate conversion circuit The circuit 1046 is connected between the second primary circuit 10232 and the primary coil of the second high-frequency transformer T2, and the fourth intermediate conversion circuit 1048 is connected between the second secondary circuit 10242 and the secondary coil of the second high-frequency transformer T2; wherein, the primary coil of the coupling transformer T3 is electrically connected to the first intermediate conversion circuit 1042, and the secondary coil of the coupling transformer T3 is electrically connected to the third intermediate conversion circuit 1046; or, the primary coil of the coupling transformer T3 is electrically connected to the second intermediate conversion circuit 1044, and the secondary coil of the coupling transformer T3 is electrically connected to the fourth intermediate conversion circuit 1048.

[0087] In this embodiment, the first conversion branch 1021 and the second conversion branch 1022 are connected in parallel, wherein the first conversion branch 1021 includes a first intermediate conversion circuit 1042 located on the primary side and a second intermediate conversion circuit 1044 located on the secondary side. The second conversion branch 1022 includes a third intermediate conversion circuit 1046 located on the primary side and a fourth intermediate conversion circuit 1048 located on the secondary side.

[0088] The high-frequency transformer T specifically includes a first high-frequency transformer T1 and a second high-frequency transformer T2, the first intermediate conversion circuit 1042 is connected between the first primary circuit 10231 and the primary coil of the first high-frequency transformer T1, and the second intermediate conversion circuit 1044 is connected between the first secondary circuit 10241 and the secondary coil of the first high-frequency transformer T1. The second conversion branch 1022 includes a third intermediate conversion circuit 1046 and a fourth intermediate conversion circuit 1048, the third intermediate conversion circuit 1046 is connected between the second primary circuit 10232 and the primary coil of the second high-frequency transformer T2, and the fourth intermediate conversion circuit 1048 is connected between the second secondary circuit 10242 and the secondary coil of the second high-frequency transformer T2.

[0089] In one case, the primary coil and the secondary coil of the coupling transformer T3 are electrically connected to the intermediate conversion circuit 104 on the primary side of the first conversion branch 1021 and the second conversion branch 1022, respectively. Exemplarily, the primary coil of the coupling transformer T3 is electrically connected to the positive line of the first intermediate conversion circuit 1042, and the secondary coil of the coupling transformer T3 is electrically connected to the negative line of the third intermediate conversion circuit 1046. At this time, the current values ​​of the primary coil and the secondary coil of the coupling transformer T3 are equal, and the current directions are opposite.

[0090] In another case, the primary coil and the secondary coil of the coupling transformer T3 are respectively electrically connected to the intermediate conversion circuit 104 on the secondary side of the first conversion branch 1021 and the second conversion branch 1022. Exemplarily, the primary coil of the coupling transformer T3 is electrically connected to the positive line of the second intermediate conversion circuit 1044, and the secondary coil of the coupling transformer T3 is electrically connected to the negative line of the fourth intermediate conversion circuit 1048. At this time, the current values ​​of the primary coil and the secondary coil of the coupling transformer T3 are equal, and the current directions are opposite.

[0091] By arranging the two coils of the coupling transformer T3 to be respectively connected to the primary side of the parallel conversion branch 102, or respectively connected to the secondary side of the parallel conversion branch 102, the currents of the two conversion branches 102 can be kept consistent, thereby improving the system stability.

[0092] In some embodiments of the present application, optionally, Figure 5 The schematic diagram of the structure of the intermediate conversion circuit of some embodiments of the present application is shown as follows: Figure 5 As shown, the intermediate conversion circuit 104 includes: a first capacitor C1; a first inductor L1, a first end of the first inductor L1 is electrically connected to the first capacitor C1, and a second end of the first inductor L1 is electrically connected to the high-frequency transformer T.

[0093] In this embodiment, the intermediate conversion circuit 104 includes a first capacitor C1 and a first inductor L1 connected in series, wherein one end of the first inductor L1 is connected to the first capacitor C1 and the other end is electrically connected to the high-frequency transformer T. That is, the first inductor L1 is located between the first capacitor C1 and the high-frequency transformer T.

[0094] In some embodiments of the present application, optionally, Figure 6 The schematic diagram of the structure of the intermediate conversion circuit of some embodiments of the present application is shown as follows: Figure 6 As shown, the intermediate conversion circuit 104 includes: a second capacitor C2, which is connected in series between the primary circuit 1023 and the high-frequency transformer T; or, the second capacitor C2 is connected in series between the secondary circuit 1024 and the high-frequency transformer T.

[0095] In this embodiment, the intermediate conversion circuit 104 includes a second capacitor C2, and the second capacitor C2 is located between the primary circuit 1023 and the high-frequency transformer T, or between the secondary circuit 1024 and the high-frequency transformer.

[0096] Exemplarily, the circuit structures of the intermediate conversion circuit 104 between the primary circuit 1023 and the high-frequency transformer T and the intermediate conversion circuit 104 between the secondary circuit 1024 and the high-frequency transformer T may be the same or different. For example, the intermediate conversion circuit 104 between the primary circuit 1023 and the high-frequency transformer T includes a first capacitor C1 and a first inductor L1 connected in series, and the intermediate conversion circuit 104 between the secondary circuit 1024 and the high-frequency transformer T includes a second capacitor C2. For example, the intermediate conversion circuit 104 between the primary circuit 1023 and the high-frequency transformer T includes a first capacitor C1 and a first inductor L1 connected in series, and the intermediate conversion circuit 104 between the secondary circuit 1024 and the high-frequency transformer T also includes a first capacitor C1 and a first inductor L1 connected in series.

[0097] In some embodiments of the present application, optionally, Figure 7 and Figure 8 The structural schematic diagram of the bridge circuit of some embodiments of the present application is shown as follows: Figure 7 and Figure 8 As shown, the primary circuit 1023 includes a first bridge circuit 106, and the secondary circuit 1024 includes a second bridge circuit 108; wherein the first bridge circuit 106 is a half-bridge rectifier circuit or a full-bridge rectifier circuit; and the second bridge circuit 108 is a half-bridge rectifier circuit or a full-bridge rectifier circuit.

[0098] In this embodiment, the primary circuit 1023 and the secondary circuit 1024 are both bridge circuits, wherein the primary circuit 1023 includes a first bridge circuit 106, and the secondary circuit 1024 includes a second bridge circuit 108, and the first bridge circuit and the second bridge circuit 108 can both be full-bridge rectifier circuits or half-bridge rectifier circuits.

[0099] Exemplarily, the first bridge circuit 106 is a full-bridge rectifier circuit, and the second bridge circuit 108 is a full-bridge rectifier circuit.

[0100] Exemplarily, the first bridge circuit 106 is a half-bridge rectifier circuit, and the second bridge circuit 108 is a half-bridge rectifier circuit.

[0101] Exemplarily, the first bridge circuit 106 is a full-bridge rectifier circuit, and the second bridge circuit 108 is a half-bridge rectifier circuit.

[0102] Exemplarily, the first bridge circuit 106 is a half-bridge rectifier circuit, and the second bridge circuit 108 is a full-bridge rectifier circuit.

[0103] The working modes of the first bridge circuit 106 and the second bridge circuit 108 can be the same or different. In the two parallel conversion branches 102, the working modes of the bridge circuits located on the primary side are the same. For example, the first bridge circuit 106 in the first conversion branch 1021 is defined as bridge circuit 1, and the second bridge circuit 108 in the first conversion branch is defined as bridge circuit 2. The first bridge circuit 106 in the second conversion branch 1022 is defined as bridge circuit 3, and the second bridge circuit 108 in the second conversion branch 1022 is defined as bridge circuit 4.

[0104] Then the working modes of bridge circuit 1 and bridge circuit 3 are the same, and the working modes of bridge circuit 2 and bridge circuit 4 are the same.

[0105] The working modes of the bridge circuit include frequency modulation, duty cycle modulation, phase shift or fixed frequency duty cycle mode.

[0106] In some embodiments of the present application, optionally, the primary circuit 1023 includes a third capacitor C3, and the first bridge circuit 106 is connected to the input source V1 through the third capacitor C3; the secondary circuit 1024 includes a fourth capacitor C4, and the second bridge circuit 108 is connected to the output source V2 through the fourth capacitor C4.

[0107] In this embodiment, the primary circuit 1023 includes a third capacitor C3, which is connected in parallel with the input source V1. The third capacitor C3 can buffer the energy of the input source V1 and absorb the high-frequency spikes generated by the load fluctuation of the line of the primary circuit 1023. The fourth capacitor C4 is connected in parallel with the output source V2. The fourth capacitor C4 can buffer the energy of the output source V2 and absorb the high-frequency spikes generated by the load fluctuation of the line of the secondary circuit 1024.

[0108] In some embodiments of the present application, a DC charging pile is provided, including: a charging gun, the charging gun is used to connect to an electric vehicle; a DCDC conversion circuit as provided in any of the above embodiments, the first end of the DCDC conversion circuit is connected to the energy storage power supply system, and the second end is connected to the charging gun. Therefore, the DC charging pile also includes the same technical effects, and to avoid repetition, it will not be repeated here.

[0109] In some embodiments of the present application, optionally, the DCDC conversion circuit is configured so that when the energy storage power supply system charges the electric vehicle, the power direction of the DCDC conversion circuit flows from the first end to the second end; when the electric vehicle charges the energy storage power supply system, the power direction of the DCDC conversion circuit flows from the second end to the first end.

[0110] In this embodiment, when the DC charging pile is connected to the electric vehicle, in one case, the power of the DCDC conversion circuit flows from the first end to the second end, and the electric vehicle is charged by the energy storage power supply system. In another case, the power of the DCDC conversion circuit flows from the second end to the first end, and the electric vehicle charges the energy storage power supply system, thereby achieving bidirectional charging.

[0111] In some embodiments of the present application, an energy storage system is provided, including: at least one battery pack, at least one battery pack is used to store electrical energy or output electrical energy; a DC charging pile, the DC charging pile integrates a DCDC conversion circuit as provided in any of the above embodiments, and therefore also includes the same technical effects, which will not be described here to avoid repetition.

[0112] In the description of this application, the term "plurality" refers to two or more than two. Unless otherwise clearly defined, the terms "upper" and "lower" indicate positions or positional relationships based on the positions or positional relationships described in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application. The terms "connect", "install", "fixed", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0113] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0114] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A DCDC conversion circuit, characterized in that: The DCDC conversion circuit comprises: At least two conversion branches, including a first conversion branch and a second conversion branch, wherein the first conversion branch and the second conversion branch are connected in parallel; A coupling transformer, wherein the primary coil of the coupling transformer is connected in series to the first conversion branch, and the secondary coil of the coupling transformer is connected in series to the second conversion branch; wherein the turns ratio of the primary coil of the coupling transformer to the secondary coil of the coupling transformer is 1.

2. The DCDC conversion circuit according to claim 1, characterized in that: The transformation branch comprises: A primary circuit, the primary circuit being electrically connected to an input source; A secondary circuit, the secondary circuit being electrically connected to an output source; A high frequency transformer, wherein the primary coil of the high frequency transformer is electrically connected to the primary circuit, and the secondary coil of the high frequency transformer is electrically connected to the secondary circuit.

3. The DCDC conversion circuit according to claim 2, characterized in that: The first conversion branch includes a first primary circuit and a first secondary circuit, and the second conversion branch includes a second primary circuit and a second secondary circuit; Among them, the primary coil of the coupling transformer is electrically connected to the first primary circuit, and the secondary coil of the coupling transformer is electrically connected to the second primary circuit; or, the primary coil of the coupling transformer is electrically connected to the first secondary circuit, and the secondary coil of the coupling transformer is electrically connected to the second secondary circuit.

4. The DCDC conversion circuit according to claim 3, characterized in that: The transformation branch also includes: An intermediate conversion circuit, wherein the primary circuit is electrically connected to the primary coil of the high-frequency transformer via the intermediate conversion circuit, and the secondary circuit is electrically connected to the secondary coil of the high-frequency transformer via the intermediate conversion circuit.

5. The DCDC conversion circuit according to claim 4, characterized in that: The first conversion branch includes a first intermediate conversion circuit and a second intermediate conversion circuit, and the high-frequency transformer includes a first high-frequency transformer and a second high-frequency transformer; The first intermediate conversion circuit is connected between the first primary circuit and the primary coil of the first high-frequency transformer, and the second intermediate conversion circuit is connected between the first secondary circuit and the secondary coil of the first high-frequency transformer; The second conversion branch includes a third intermediate conversion circuit and a fourth intermediate conversion circuit, the third intermediate conversion circuit is connected between the second primary circuit and the primary coil of the second high-frequency transformer, and the fourth intermediate conversion circuit is connected between the second secondary circuit and the secondary coil of the second high-frequency transformer; Among them, the primary coil of the coupling transformer is electrically connected to the first intermediate conversion circuit, and the secondary coil of the coupling transformer is electrically connected to the third intermediate conversion circuit; or, the primary coil of the coupling transformer is electrically connected to the second intermediate conversion circuit, and the secondary coil of the coupling transformer is electrically connected to the fourth intermediate conversion circuit.

6. The DCDC conversion circuit according to claim 4, characterized in that: The intermediate conversion circuit comprises: a first capacitor; A first inductor, wherein a first end of the first inductor is electrically connected to the first capacitor, and a second end of the first inductor is electrically connected to the high-frequency transformer.

7. The DCDC conversion circuit according to claim 4, characterized in that: The intermediate conversion circuit comprises: A second capacitor is connected in series between the primary circuit and the high-frequency transformer; or, the second capacitor is connected in series between the secondary circuit and the high-frequency transformer.

8. The DCDC conversion circuit according to any one of claims 2 to 7, characterized in that: The primary circuit includes a first bridge circuit, and the secondary circuit includes a second bridge circuit; Among them, the first bridge circuit is a half-bridge rectifier circuit or a full-bridge rectifier circuit; the second bridge circuit is a half-bridge rectifier circuit or a full-bridge rectifier circuit.

9. The DCDC conversion circuit according to claim 8, characterized in that: The primary circuit includes a third capacitor, and the first bridge circuit is connected to the input source via the third capacitor; The secondary circuit includes a fourth capacitor, and the second bridge circuit is connected to the output source via the fourth capacitor.

10. A DC charging pile, characterized in that: include: A charging gun, which is used to connect to an electric vehicle; The DCDC conversion circuit according to any one of claims 1 to 9, wherein a first end of the DCDC conversion circuit is connected to the energy storage power supply system, and a second end of the DCDC conversion circuit is connected to the charging gun.

11. The DC charging pile according to claim 10, characterized in that: The DCDC conversion circuit is configured so that when the energy storage power supply system charges the electric vehicle, the power of the DCDC conversion circuit flows from the first end to the second end; and when the electric vehicle charges the energy storage power supply system, the power of the DCDC conversion circuit flows from the second end to the first end.

12. An energy storage system, characterized in that: include: at least one battery pack, the at least one battery pack being used to store electrical energy or output electrical energy; A DC charging pile, wherein the DC charging pile integrates a DCDC conversion circuit as claimed in any one of claims 1 to 9.

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