Bidirectional direct-current power converter, direct-current charging pile and energy storage power supply system

Abstract

The utility model discloses a bidirectional DC power converter and a DC charging pile, and the converter comprises a first end, a second end, at least two bidirectional DCDC units, a primary side switch, a secondary side switch, a first switching circuit, a second switching circuit, and a controller. The bidirectional DCDC unit comprises a transformer, a primary side DCDC circuit and a primary side resonance network which are sequentially connected between the first end and the primary side of the transformer, and a secondary side DCDC circuit and a secondary side resonance network which are sequentially connected between the second end and the secondary side of the transformer; and the controller is configured to control the at least two primary DCDC circuits to form series connection or parallel connection, and / or control the at least two secondary DCDC circuits to form series connection or parallel connection and control the on-off of the primary switch and the secondary switch. The bidirectional direct-current power converter provided by the utility model can be suitable for different scenes, the voltage regulation capability of the bidirectional direct-current power converter is improved, the conversion efficiency is ensured, components with higher bearing capability do not need to be used, and the device cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and more particularly, to a bidirectional DC power converter, a DC charging pile, and an energy storage power system. Background Art

[0002] Bidirectional DC power converters usually have a variety of topologies and are suitable for different scenarios, such as high-voltage input, low-voltage input, high-voltage output, or low-voltage output. However, with the development and popularization of new energy vehicle technology, a bidirectional DC power converter with the same topology may need to be applied in different scenarios, which may result in poor voltage regulation ability at both ends and a decrease in conversion efficiency. Summary of the Utility Model

[0003] Embodiments of the present application provide a bidirectional DC power converter and a DC charging pile.

[0004] The bidirectional DC power converter according to the embodiments of the present application includes:

[0005] A first end;

[0006] A second end;

[0007] At least two bidirectional DCDC units, each of the bidirectional DCDC units including a transformer, a primary DCDC circuit and a primary resonance network connected in sequence between the first end and the primary side of the transformer, and a secondary DCDC circuit and a secondary resonance network connected in sequence between the second end and the secondary side of the transformer;

[0008] A primary switch connected in parallel with the primary resonance network and connected between the primary DCDC circuit and the primary side of the transformer;

[0009] A secondary switch connected in parallel with the secondary resonance network and connected between the secondary DCDC circuit and the secondary side of the transformer;

[0010] A first switch circuit connected between the first end and the primary DCDC circuit;

[0011] A second switch circuit connected between the second end and the secondary DCDC circuit;

[0012] A controller configured to control the on / off of the switches in the first switch circuit so that the primary DCDC circuits of the at least two bidirectional DCDC units form a series or parallel connection, and / or control the on / off of the switches in the second switch circuit so that the secondary DCDC circuits of the at least two bidirectional DCDC units form a series or parallel connection, and control the on / off of the primary switch and the secondary switch.

[0013] The bidirectional DC power converter provided by this application controls the on-off of the primary switch and the secondary switch through a controller, changing the topological structure of multiple bidirectional DCDC units in the bidirectional DC power converter. Therefore, the bidirectional DC power converter can be applicable to different scenarios, thereby improving the voltage regulation ability of the bidirectional DC power converter, ensuring the conversion efficiency, and at the same time controlling the on-off of the switches in the first switch circuit and the second switch circuit through the controller, thereby realizing the switching between series and parallel connections of the two primary DCDC circuits and the switching between series and parallel connections of the two secondary DCDC circuits. This not only enables the bidirectional DC power converter to accept larger voltages and currents, but also eliminates the need to use components with higher load-carrying capacities, effectively reducing the device cost.

[0014] In some embodiments, the primary resonant network includes a first capacitor and a first inductor connected in series in sequence between the primary DCDC circuit and the primary side of the transformer;

[0015] The secondary resonant network includes a second inductor and a second capacitor connected in series in sequence between the secondary DCDC circuit and the secondary side of the transformer.

[0016] In this way, the primary resonant network and the secondary resonant network can utilize the energy storage characteristics of the inductor and the capacitor to achieve resonance through the alternating conversion of electromagnetic energy.

[0017] In some embodiments, the primary switch and the secondary switch are high-frequency switching switches.

[0018] In this way, the output voltage of the high-frequency switching power supply has high stability, is not easily affected by changes in the input voltage and the load, and has higher energy conversion efficiency.

[0019] In some embodiments, the primary switch and the secondary switch are any one of MOS transistors, IGBTs or relays.

[0020] In this way, selecting MOS transistors, IGBTs or relays for the primary switch and the secondary switch can be respectively applicable to different usage scenarios, which is beneficial to broadening the usage range of the bidirectional DC power converter.

[0021] In some embodiments, the controller is used to control the disconnection of the primary switch and the disconnection of the secondary switch, so that the bidirectional DC power converter operates in the asymmetric CLLC mode.

[0022] In this way, making the bidirectional DC power conversion circuit operate in the CLLC mode can realize the bidirectional flow of electric energy, which is beneficial to obtaining a higher power conversion efficiency.

[0023] In some embodiments, the controller is configured to control the primary side switch to turn off and the secondary side switch to turn on, so that the bidirectional DC power converter operates in the forward LLC mode.

[0024] In this way, enabling the bidirectional DCDC unit to operate in the LLC mode is beneficial to achieving high-efficiency power conversion, and its structure is relatively simple, making it easy to achieve high power density and low cost.

[0025] In some embodiments, the controller is configured to control the primary side switch to turn on and the secondary side switch to turn on, so that the bidirectional DC power converter operates in the full-bridge circuit mode.

[0026] In this way, enabling the bidirectional DCDC unit to operate in the full-bridge circuit mode facilitates handling larger currents and meeting the application scenarios of high-power output.

[0027] In some embodiments, the controller is configured to control the primary side switch to turn on and the secondary side switch to turn off, so that the bidirectional DC power converter operates in the reverse LLC mode.

[0028] In this way, enabling the bidirectional DCDC unit to operate in the LLC mode is beneficial to achieving high-efficiency power conversion, and its structure is relatively simple, making it easy to achieve high power density and low cost.

[0029] In some embodiments, the bidirectional DC power converter includes a first bidirectional DCDC unit and a second bidirectional DCDC unit. The first bidirectional DCDC unit includes a first transformer, a first primary-side DCDC circuit and a first primary-side resonant network connected in sequence between the first end and the primary side of the first transformer, and a first secondary-side DCDC circuit and a first secondary-side resonant network connected in sequence between the second end and the secondary side of the first transformer;

[0030] The second bidirectional DCDC unit includes a second transformer, a second primary-side DCDC circuit and a second primary-side resonant network connected in sequence between the first end and the primary side of the second transformer, and a second secondary-side DCDC circuit and a second secondary-side resonant network connected in sequence between the second end and the secondary side of the second transformer.

[0031] In this way, setting two bidirectional DCDC units can achieve acceptance of larger voltages and currents, while being beneficial to cost savings.

[0032] In some embodiments, the first switch circuit includes a first switch connected between the positive electrode of the first end and the second primary-side DCDC circuit, a second switch connected between the first primary-side DCDC circuit and the second primary-side DCDC circuit, and a third switch connected between the negative electrode of the first end and the first primary-side DCDC circuit;

[0033] The second switching circuit includes a fourth switch connected between the positive electrode of the second terminal and the second secondary DCDC circuit, a fifth switch connected between the first secondary DCDC circuit and the second secondary DCDC circuit, and a sixth switch connected between the negative electrode of the second terminal and the first secondary DCDC circuit.

[0034] In this way, by turning on and off three switches, not only the switching between series connection and parallel connection of the two primary DCDC circuits is realized, but also the fewest switches are used, which is beneficial to cost saving.

[0035] In some embodiments, the first primary DCDC circuit includes a first primary full-bridge circuit and a first primary capacitor connected in parallel. The two ends of the first primary full-bridge circuit are connected to the two ends of the first primary capacitor. The other two ends of the first primary full-bridge circuit are connected to the two electrodes of the primary side of the first transformer. The first primary capacitor is connected to the positive and negative electrodes of the first terminal;

[0036] The second primary DCDC circuit includes a second primary full-bridge circuit and a second primary capacitor connected in parallel. The two ends of the second primary full-bridge circuit are connected to the two ends of the second primary capacitor. The other two ends of the second primary full-bridge circuit are connected to the two electrodes of the primary side of the second transformer. The second primary capacitor is connected to the positive and negative electrodes of the first terminal;

[0037] The first secondary DCDC circuit includes a first secondary full-bridge circuit and a first secondary capacitor connected in parallel. The two ends of the first secondary full-bridge circuit are connected to the two ends of the first secondary capacitor. The other two ends of the first secondary full-bridge circuit are connected to the two electrodes of the secondary side of the first transformer. The first secondary capacitor is connected to the positive and negative electrodes of the second terminal;

[0038] The second secondary DCDC circuit includes a second secondary full-bridge circuit and a second secondary capacitor connected in parallel. The two ends of the second secondary full-bridge circuit are connected to the two ends of the second secondary capacitor. The other two ends of the second secondary full-bridge circuit are connected to the two electrodes of the secondary side of the second transformer. The second secondary capacitor is connected to the positive and negative electrodes of the second terminal.

[0039] In this way, the first primary full-bridge circuit, the second primary full-bridge circuit, the first secondary full-bridge circuit, and the second secondary full-bridge circuit are used to realize the bidirectional flow of current according to the control signal, and the reliability of the bidirectional DC power converter can also be improved.

[0040] In some embodiments, one end of the first primary capacitor is connected to the positive electrode of the first terminal, and the other end is respectively connected to the negative electrode of the first terminal through the third switch and to the second primary capacitor through the second switch;

[0041] One end of the second primary-side capacitor is connected to the negative electrode of the first end, and the other end is respectively connected to the positive electrode of the first end through the first switch and to the first primary-side capacitor through the second switch;

[0042] One end of the first secondary-side capacitor is connected to the positive electrode of the second end, and the other end is respectively connected to the negative electrode of the second end through the sixth switch and to the second secondary-side capacitor through the fifth switch;

[0043] One end of the second secondary-side capacitor is connected to the negative electrode of the second end, and the other end is respectively connected to the positive electrode of the second end through the fourth switch and to the first secondary-side capacitor through the fifth switch.

[0044] In this way, the first primary-side capacitor, the second primary-side capacitor, the first secondary-side capacitor, and the second secondary-side capacitor can be used to smooth the pulsation and noise of the output voltage, making the output voltage more stable.

[0045] In some embodiments, the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and / or the sixth switch are high-frequency switching switches.

[0046] In this way, the output voltage of the high-frequency switching power supply has high stability, is not easily affected by changes in the input voltage and load, and has a higher energy conversion efficiency.

[0047] In some embodiments, the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and / or the sixth switch are any one of MOS transistors, IGBTs, or relays.

[0048] In this way, selecting MOS transistors, IGBTs, or relays for the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch can be respectively applicable to different usage scenarios, which is beneficial to broadening the usage range of the bidirectional DC power converter.

[0049] In some embodiments, the bidirectional DC power converter further includes a voltage detection circuit, and the voltage detection circuit is connected in parallel to the first end and / or the second end.

[0050] In this way, the voltages of the first end and the second end can be detected at any time through the voltage detection circuit to avoid overvoltage.

[0051] In some embodiments, the voltage detection circuit includes an operational amplifier and several resistors connected in series. Two input terminals of the operational amplifier are connected to both ends of any one of the resistors, and the output terminal of the operational amplifier is connected to the controller.

[0052] In this way, detecting the voltages at the first end and the second end through the operational amplifier and the controller facilitates a more timely response to problems such as overvoltage.

[0053] In some embodiments, the voltage detection circuit includes an isolator, an operational amplifier, and a plurality of resistors connected in series, the isolator is connected in parallel with any one of the resistors, the output end of the isolator is connected to the operational amplifier, and the output end of the operational amplifier is connected to the controller.

[0054] In this way, the isolator can reduce errors caused by signal interference and leakage, and improve the accuracy and reliability of sampling.

[0055] In some embodiments, the controller is configured to control the first switch and the third switch to be turned off and the second switch to be turned on when the voltage at the first end is greater than a predetermined voltage.

[0056] In this way, when the voltage at the first end is high, the first primary DCDC circuit and the second primary DCDC circuit at the first end form a voltage dividing circuit to avoid damage to electrical components caused by excessive voltage.

[0057] In some embodiments, the controller is configured to control the second switch to be turned off and the first switch and the third switch to be turned on when the voltage at the first end is less than or equal to the predetermined voltage.

[0058] In this way, when the voltage at the first end is low, at this time the current at the first end is large, and the first primary DCDC circuit and the second primary DCDC circuit at the first end form a current shunting circuit to avoid damage to electrical components caused by excessive current.

[0059] In some embodiments, the controller is configured to control the fourth switch and the sixth switch to be turned off and the fifth switch to be turned on when the voltage at the second end is greater than a predetermined voltage.

[0060] In this way, when the voltage at the second end is high, the first secondary DCDC circuit and the second secondary DCDC circuit at the second end both form a voltage dividing circuit to avoid damage to electrical components caused by excessive voltage.

[0061] In some embodiments, the controller is configured to control the fifth switch to be turned off and the fourth switch and the sixth switch to be turned on when the voltage at the second end is less than or equal to the predetermined voltage.

[0062] In this way, when the voltage at the second end is low, at this time the current at the second end is large, and the first secondary DCDC circuit and the second secondary DCDC circuit at the second end form a current shunting circuit to avoid damage to electrical components caused by excessive current.

[0063] In some embodiments, the primary resonant network includes a first capacitor and a first inductor connected in series between the primary DCDC circuit and the primary side of the transformer in sequence;

[0064] The secondary resonant network includes a second inductor and a second capacitor connected in series between the secondary DCDC circuit and the secondary side of the transformer in sequence.

[0065] In this way, the primary resonant network and the secondary resonant network can utilize the energy storage characteristics of the inductor and the capacitor to achieve resonance through the alternating conversion of electromagnetic energy.

[0066] A DC charging pile according to another embodiment of the present application includes:

[0067] A charging gun for connecting to an electric vehicle;

[0068] The bidirectional DC power converter as described in any one of the above, with the first end connected to the energy storage power supply system and the second end connected to the charging gun.

[0069] In some embodiments, the bidirectional DC power conversion circuit is configured such that when the energy storage power supply system charges the electric vehicle, the power flow direction of the bidirectional DC power conversion circuit is from the first end to the second end, and when the electric vehicle charges the energy storage power supply system, the power flow direction of the bidirectional DC power conversion circuit is from the second end to the first end.

[0070] In this way, the first end can be connected to the input end of the DC charging pile, and the second end can be connected to the output end of the DC charging pile.

[0071] An energy storage power supply system according to still another embodiment of the present application includes:

[0072] At least one battery pack for storing or outputting electric energy;

[0073] An inverter integrating the bidirectional DC power converter as described in any one of the above.

[0074] The additional aspects and advantages of the embodiments of the present application will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] The above and / or additional aspects and advantages of the present application will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, in which:

[0076] Figure 1It is a schematic diagram of the modules of the bidirectional DC power converter according to the embodiments of the present application;

[0077] Figure 2 It is the circuit diagram of the bidirectional DC power converter according to the embodiments of the present application;

[0078] Figure 3 It is the circuit diagram of the bidirectional DC power converter according to the embodiments of the present application;

[0079] Figure 4 It is the circuit diagram of the bidirectional DC power converter according to some embodiments of the present application;

[0080] Figure 5 It is the circuit diagram of the bidirectional DC power converter according to some embodiments of the present application.

[0081] Description of main component symbols: DC charging pile 1000, bidirectional DC power converter 100, first terminal 10, second terminal 20, bidirectional DCDC unit 30, first bidirectional DCDC unit 31, second bidirectional DCDC unit 32, transformer 33, first transformer 331, second transformer 332, primary DCDC circuit 34, first primary DCDC circuit 341, first primary full-bridge circuit 3411, first primary capacitor 3412, second primary DCDC circuit 342, second primary full-bridge circuit 3421, second primary capacitor 3422, secondary DCDC circuit 35, first secondary DCDC circuit 351, first secondary full-bridge circuit 3511, first secondary capacitor 3512, second secondary DCDC circuit 352, second secondary full-bridge circuit 3521, second secondary capacitor 3522, primary resonance network 36, first primary resonance network 361, second primary resonance network 362, first inductor 363, first capacitor 364, secondary resonance network 37, first secondary resonance network 371, second secondary resonance network 372, second inductor 373, second capacitor 374, primary switch 38, secondary switch 39, first switch circuit 40, first switch 41, second switch 42, third switch 43, second switch circuit 50, fourth switch 51, fifth switch 52, sixth switch 53, controller 60, voltage detection circuit 70, operational amplifier 71, resistor 72, isolator 73, charging gun 200. Specific embodiments

[0082] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary only for explaining the present application and should not be construed as limiting the present application. In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application. In the description of the present application, the meaning of "a plurality of" is two or more unless otherwise specifically defined.

[0083] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection. It may be a mechanical connection or an electrical connection. It may be directly connected or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0084] In the present application, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0085] The disclosure of this article provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure of this application, the components and settings of specific examples are described herein. Of course, they are only examples and are not intended to limit this application. In addition, this application may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, this application provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0086] Bidirectional DC power converters usually have a variety of topologies and are suitable for different scenarios, such as high-voltage input, low-voltage input, high-voltage output, or low-voltage output. However, with the development and popularization of new energy vehicle technology, a bidirectional DC power converter of the same topology may need to be applied in different scenarios, which may result in poor voltage regulation ability at both ends and a decrease in conversion efficiency.

[0087] The following explains the technical problems to be solved by this application in the scenario of a DC charging pile to help understand this solution, but this solution is not limited to DC charging piles and can also be used in energy storage inverters, etc.:

[0088] In the field of DC charging piles, this application mainly solves two problems. First, it is to broaden the input voltage range that the DCDC converter of the existing DC charging pile can withstand. Second, it is to broaden the output voltage range that the DCDC converter of the existing DC charging pile can withstand, and on the premise of broadening the input voltage and output voltage ranges, maintain a high efficiency of the DCDC converter.

[0089] The problems existing in the existing DC charging piles are analyzed as follows. On the one hand, the input end of the DCDC converter of the existing DC charging pile is usually only connected to the grid end, and the grid voltage range is relatively narrow, such as between 380V and 800V. Therefore, the circuit design of the existing DCDC converter only needs to adapt to the grid voltage range (relatively narrow). However, with the rapid development of green energy, such as home energy storage, current users can use the energy storage battery of home energy storage to supply power to the DC charging pile instead of the grid. However, the voltage range of the energy storage battery is wider than that of the grid end. For example, it is between 150V and 1000V. Therefore, the output end of the DCDC converter of the existing DC charging pile cannot well adapt to the energy storage battery to supply power. On the other hand, the output end of the DCDC converter of the existing DC charging pile only considers the charging voltage of electric vehicles of common models on the market, and its output voltage range is also relatively narrow, such as between 200V and 500V. However, for small electric vehicles with a low charging voltage (150V), such as elderly mobility scooters and low-speed electric vehicles, and large electric vehicles with a high charging voltage requirement (1000V), such as electric heavy trucks, the existing DC charging piles cannot meet the requirements.

[0090] In order to meet the voltage range of the energy storage battery that can be compatible at the input end (wide input voltage range), and to meet the electric vehicles with various different charging voltage ranges that can be compatible at the output end (wide output voltage range), a new DCDC converter of this solution is proposed.

[0091] Taking the bidirectional DC charging pile as an example, that is, the energy storage battery (input end) can charge the electric vehicle (output end) through the DC charging pile, and the electric vehicle (input end) can also charge the energy storage battery (output end) through the DC charging pile. The reasons for the low efficiency after broadening the DCDC input and output voltage ranges are analyzed below. Here, the efficiency refers to the ratio of the input power to the output power. For example, if the input power of the DCDC converter is 30kW and the output power is also 29kW, then its efficiency is 29 / 30 = 96.7%. After the existing DCDC converter broadens the input and output voltage ranges, its efficiency usually becomes lower, especially when the output is at a low voltage, the efficiency reduction is more obvious. For example, with the same input power of 30KW, when outputting 30KW power at a high voltage of 1000V, according to P = UI, the required output current is theoretically 30A; while if outputting 30KW power at a low voltage of 300V, according to P = UI, the required output current is theoretically 100A. And power devices usually have difficulty in withstanding large currents, and there will be relatively large losses in the case of large currents, such as 100V. Therefore, there will be a relatively large loss in the output power when the output is at a low voltage. For example, here the input power is 30kW, when the output is at a low voltage, due to the current loss, its output power may only be 15kW, that is, the efficiency of the DCDC is only 15kW / 30kW = 50%.

[0092] To solve the technical problems existing in the prior art, the present application proposes a bidirectional DC power converter and a DC charging pile, which not only enable the bidirectional DC power converter to accept a larger voltage and current, but also do not require components with a larger load capacity, effectively reducing the device cost. The following is a detailed description.

[0093] Please refer to Figure 1 , the present application provides a DC charging pile 1000, including a charging gun 200 and a bidirectional DC power converter 100. The charging gun 200 is used to connect to an electric vehicle. The first end 10 is connected to an energy storage power system, and the second end 20 is connected to the charging gun 200. The bidirectional DC power converter 100 includes a first end 10, a second end 20, at least two bidirectional DCDC units 30, a primary switch 38 connected in parallel with the primary resonant network 36 and connected between the primary DCDC circuit 34 and the primary side of the transformer 33, a secondary switch 39 connected in parallel with the secondary resonant network 37 and connected between the secondary DCDC circuit 35 and the secondary side of the transformer 33, a first switch circuit 40 connected between the first end 10 and the primary DCDC circuit 34, a second switch circuit 50 connected between the second end 20 and the secondary DCDC circuit 35, and a controller 60. Each bidirectional DCDC unit 30 includes a transformer 33, a primary DCDC circuit 34 and a primary resonant network 36 connected in sequence between the first end 10 and the primary side of the transformer 33, and a secondary DCDC circuit 35 and a secondary resonant network 37 connected in sequence between the second end 20 and the secondary side of the transformer 33; the controller 60 is configured to control the on / off of the switches in the first switch circuit 40 so that a series or parallel connection is formed between the primary DCDC circuits 34 of at least two bidirectional DCDC units 30, and / or control the on / off of the switches in the second switch circuit 50 so that a series or parallel connection is formed between the secondary DCDC circuits 35 of at least two bidirectional DCDC units 30, and control the on / off of the primary switch 38 and the secondary switch 39.

[0094] The bidirectional DC power converter 100 provided by the present application controls the on / off of the primary switch 38 and the secondary switch 39 through the controller 60, changing the topological structure of multiple bidirectional DCDC units 30 in the bidirectional DC power converter 100. Therefore, the bidirectional DC power converter 100 can be applied to different scenarios, thereby improving the voltage regulation ability of the bidirectional DC power converter 100, ensuring the conversion efficiency. At the same time, by controlling the on / off of the switches in the first switch circuit 40 and the second switch circuit 50 through the controller 60, the switching between series and parallel connections of the two primary DCDC circuits 34 and the switching between series and parallel connections of the two secondary DCDC circuits 35 are realized. While the bidirectional DC power converter 100 can accept a larger voltage and current, it does not require components with a larger load capacity, effectively reducing the device cost.

[0095] In some embodiments, the primary resonant network 36 includes a first capacitor 364 and a first inductor 363 that are connected in series in sequence between the primary DCDC circuit 34 and the primary side of the transformer 33;

[0096] The secondary resonant network 37 includes a second inductor 373 and a second capacitor 374 that are connected in series in sequence between the secondary DCDC circuit 35 and the secondary side of the transformer 33.

[0097] In this way, the primary resonant network 36 and the secondary resonant network 37 can utilize the energy storage characteristics of the inductor and the capacitor to achieve resonance through the alternating conversion of electromagnetic energy.

[0098] In some embodiments, the primary switch 38 and the secondary switch 39 are high-frequency switching switches.

[0099] In this way, the output voltage of the high-frequency switching power supply has high stability, is not easily affected by the changes of the input voltage and the load, and has higher energy conversion efficiency.

[0100] In some embodiments, the primary switch 38 and the secondary switch 39 are any one of MOS transistors, IGBTs or relays.

[0101] In this way, selecting MOS transistors, IGBTs or relays for the primary switch 38 and the secondary switch 39 can be respectively applicable to different usage scenarios, which is beneficial to broadening the usage range of the bidirectional DC power converter 100.

[0102] Please refer to Figure 2 and Figure 3 , in some embodiments, the controller 60 is used to control the primary switch 38 to turn off and the secondary switch 39 to turn off, so that the bidirectional DC power converter 100 operates in the asymmetric CLLC mode.

[0103] In this way, making the bidirectional DCDC unit 30 operate in the CLLC mode can realize the bidirectional flow of electric energy, which is beneficial to obtaining higher power conversion efficiency.

[0104] Specifically, in the embodiments of the present application, the controller 80 can be used to control the primary switch 38 to turn off and the secondary switch 39 to turn off according to the actual usage requirements and electrical parameters, so that the bidirectional DC power converter 100 enters the CLLC mode.

[0105] The CLLC mode is a typical topology of a bidirectional full-bridge LLC resonant converter, which consists of a forward LLC and a reverse LC topology. The CLLC mode has soft-switching characteristics, high energy efficiency, can effectively reduce electromagnetic interference, improve the stability and reliability of the system, and the operating frequency of the CLLC mode is close to the resonant frequency, enabling the power devices to achieve zero-voltage switching (ZVS) and zero-current switching (ZCS), and the converter has high efficiency.

[0106] In some embodiments, the controller 60 is used to control the primary switch 38 to turn off and the secondary switch 39 to turn on, so that the bidirectional DC power converter 100 operates in the forward LLC mode.

[0107] In this way, enabling the bidirectional DCDC unit 30 to operate in the LLC mode is conducive to achieving high-efficiency power conversion, and its structure is relatively simple, making it easy to achieve high power density and low cost.

[0108] Specifically, in the embodiments of the present application, the controller 80 can be used to control the primary switch 38 to turn off and the secondary switch 39 to turn on according to actual usage requirements and electrical parameters, so that the bidirectional DC power converter 100 enters the LLC mode.

[0109] The LLC mode refers to the LLC topology, that is, the LLC resonant converter mode, which is a switching power supply control topology widely used in the field of power electronics. The LLC topology mainly consists of an inductor, a capacitor, and a transformer 30, forming a parallel resonant circuit. By adjusting the values of the inductor and capacitor, resonance of current and voltage can be achieved, thereby improving the power conversion efficiency. It should be noted that the LLC mode is more suitable for the bidirectional DC power converter 100 that requires high efficiency, wide voltage range, high power density, good dynamic response ability, low electromagnetic interference, and high reliability.

[0110] The LLC mode can improve the slope of the gain curve, and enhance the voltage regulation ability of the bidirectional DCDC unit 30 by changing the slope of the resonant converter gain curve. By controlling the operating frequency close to the resonant frequency through an algorithm, the power devices can achieve zero-voltage switching (ZVS) and zero-current switching (ZCS), and the converter has high efficiency.

[0111] In some embodiments, the controller 60 is used to control the primary switch 38 to turn on and the secondary switch 39 to turn on, so that the bidirectional DC power converter 100 operates in the full-bridge circuit mode.

[0112] In this way, the bidirectional DCDC unit 30 operates in the full-bridge circuit mode, which is convenient for handling larger currents and meeting the application scenarios of high-power output.

[0113] Specifically, in the embodiments of the present application, the controller 80 can be used to control the conduction of the primary switch 38 and the conduction of the secondary switch 39 according to actual usage requirements and electrical parameters, so that the bidirectional DC power converter 100 enters the full-bridge circuit mode.

[0114] The full-bridge circuit mode is an electronic circuit topology structure. It realizes the conversion from direct current to alternating current by connecting four switching tubes (or called switching elements) in a specific way, or is used to adjust the operating state of devices such as DC motors and inverters. The working principle of the full-bridge circuit is based on the on and off states of the switching tubes. When the high-side switch is on and the low-side switch is off, the current flows from the positive pole of the power supply through the high-side switch to the load; when the low-side switch is on and the high-side switch is off, the current flows from the load through the low-side switch back to the negative pole of the power supply. By sequentially controlling the on and off of these four switching tubes, the direction of the current in the circuit can be continuously changed, thus realizing the conversion from direct current to alternating current or the forward and reverse control of the DC motor. It should be noted that the full-bridge circuit mode is more suitable for scenarios that require high efficiency, flexible control, high power, high voltage, and electrical isolation.

[0115] In some embodiments, the controller 60 is used to control the conduction of the primary switch 38 and the disconnection of the secondary switch 39, so that the bidirectional DC power converter 100 operates in the reverse LLC mode.

[0116] In this way, the bidirectional DCDC unit 30 operates in the LLC mode, which is beneficial to realizing high-efficiency power conversion, and its structure is relatively simple, making it easy to achieve high power density and low cost.

[0117] Specifically, in the embodiments of the present application, the controller 80 can be used to control the conduction of the primary switch 38 and the disconnection of the secondary switch 39 according to actual usage requirements and electrical parameters, so that the bidirectional DC power converter 100 enters the LLC mode.

[0118] The reverse LLC mode is the same as the LLC mode, and both can improve the slope of the gain curve. By changing the slope of the gain curve of the resonant converter, the voltage regulation ability of the bidirectional DCDC unit 30 can be enhanced. By controlling the operating frequency close to the resonant frequency through an algorithm, the power devices can achieve zero-voltage switching ZVS (Zero Voltage Switch) and zero-current switching ZCS (Zero Current Switch), and the converter has high efficiency.

[0119] In some embodiments, the bidirectional DC power converter 100 includes a first bidirectional DC-DC unit 31 and a second bidirectional DC-DC unit 32. The first bidirectional DC-DC unit 31 includes a first transformer 331, a first primary DC-DC circuit 341 and a first primary resonant network 361 connected in sequence between the first end 10 and the primary side of the first transformer 331, and a first secondary DC-DC circuit 351 and a first secondary resonant network 371 connected in sequence between the second end 20 and the secondary side of the first transformer 331;

[0120] The second bidirectional DC-DC unit 32 includes a second transformer 332, a second primary DC-DC circuit 342 and a second primary resonant network 362 connected in sequence between the first end 10 and the primary side of the second transformer 332, and a second secondary DC-DC circuit 352 and a second secondary resonant network 372 connected in sequence between the second end 20 and the secondary side of the second transformer 332.

[0121] In this way, setting two bidirectional DC-DC units 30 can achieve acceptance of a larger voltage and current, and at the same time is conducive to cost savings.

[0122] Specifically, in the embodiments of the present application, the first bidirectional DC-DC unit 31 and the second bidirectional DC-DC unit 32 are arranged in parallel. In other embodiments of the application, the number of bidirectional DC-DC converters 100 can also be other numbers.

[0123] In some embodiments, the first switch circuit 40 includes a first switch 41 connected between the positive pole of the first end 10 and the second primary DC-DC circuit 342, a second switch 42 connected between the first primary DC-DC circuit 341 and the second primary DC-DC circuit 342, and a third switch 43 connected between the negative pole of the first end 10 and the first primary DC-DC circuit 341;

[0124] The second switch circuit 50 includes a fourth switch 51 connected between the positive pole of the second end 20 and the second secondary DC-DC circuit 352, a fifth switch 52 connected between the first secondary DC-DC circuit 351 and the second secondary DC-DC circuit 352, and a sixth switch 53 connected between the negative pole of the second end 20 and the first secondary DC-DC circuit 351.

[0125] In this way, the on-off of the three switches not only realizes the switching between series and parallel of the two primary DC-DC circuits 34, but also uses the fewest switches, which is conducive to cost savings.

[0126] Specifically, in the embodiments of the present application, each switching circuit is provided with three switches. Among them, when the first switch 41 and the third switch 43 are closed and the second switch 42 is open, the first primary DCDC circuit 341 and the second primary DCDC circuit 342 can be connected in parallel. When the first switch 41 and the third switch 43 are open and the second switch 42 is closed, the first primary DCDC circuit 341 and the second primary DCDC circuit 342 can be connected in series. Similarly, when the fourth switch 51 and the sixth switch 53 are closed and the fifth switch 52 is open, the first secondary DCDC circuit 351 and the second secondary DCDC circuit 352 can be connected in parallel. When the fourth switch 51 and the sixth switch 53 are open and the fifth switch 52 is closed, the first secondary DCDC circuit 351 and the second secondary DCDC circuit 352 can be connected in series.

[0127] In other embodiments, each switching circuit may also be provided with other numbers of switches for controlling the switching between series and parallel connections of the first primary DCDC circuit 341 and the second primary DCDC circuit 342 and the switching between series and parallel connections of the first secondary DCDC circuit 351 and the second secondary DCDC circuit 352.

[0128] In some embodiments, the first primary DCDC circuit 341 includes a first primary full-bridge circuit 3411 and a first primary capacitor 3412 connected in parallel. The two ends of the first primary full-bridge circuit 3411 are connected to the two ends of the first primary capacitor 3412. The other two ends of the first primary full-bridge circuit 3411 are connected to the two electrodes of the primary side of the first transformer 331. The first primary capacitor 3412 is connected to the positive and negative electrodes of the first terminal 10.

[0129] The second primary DCDC circuit 342 includes a second primary full-bridge circuit 3421 and a second primary capacitor 3422 connected in parallel. The two ends of the second primary full-bridge circuit 3421 are connected to the two ends of the second primary capacitor 3422. The other two ends of the second primary full-bridge circuit 3421 are connected to the two electrodes of the primary side of the second transformer 332. The second primary capacitor 3422 is connected to the positive and negative electrodes of the first terminal 10.

[0130] The first secondary DCDC circuit 351 includes a first secondary full-bridge circuit 3511 and a first secondary capacitor 3512 connected in parallel. The two ends of the first secondary full-bridge circuit 3511 are connected to the two ends of the first secondary capacitor 3512. The other two ends of the first secondary full-bridge circuit 3511 are connected to the two electrodes of the secondary side of the first transformer 331. The first secondary capacitor 3512 is connected to the positive and negative electrodes of the second terminal 20.

[0131] The second secondary DCDC circuit 352 includes a second secondary full-bridge circuit 3521 and a second secondary capacitor 3522 connected in parallel. The two ends of the second secondary full-bridge circuit 3521 are connected to the two ends of the second secondary capacitor 3522. The other two ends of the second secondary full-bridge circuit 3521 are connected to the two electrodes of the secondary side of the second transformer 332. The second secondary capacitor 3522 is connected to the positive and negative poles of the second terminal 20.

[0132] In this way, the first primary full-bridge circuit 3411, the second primary full-bridge circuit 3421, the first secondary full-bridge circuit 3511, and the second secondary full-bridge circuit 3521 are used to achieve bidirectional current flow according to the control signal, and can also improve the reliability of the bidirectional DC power converter 100.

[0133] Specifically, a full-bridge circuit is a circuit structure composed of four switching tubes (usually MOSFETs or IGBTs). These switching tubes are connected in a bridge manner and can achieve DC-DC or DC-AC conversion. In a DCDC circuit, the full-bridge circuit is mainly used to achieve voltage step-up and step-down conversion and bidirectional current flow. When the four switching tubes perform switching operations according to a specific timing sequence, the direction of energy flow can be controlled, thereby realizing bidirectional power conversion.

[0134] By controlling the on and off of the switching tubes, the full-bridge circuit can achieve the conversion of the input voltage to the output voltage, including boosting, bucking, or maintaining the voltage constant. In a bidirectional DC power conversion circuit, the full-bridge circuit allows current to flow bidirectionally between the input and output, realizing bidirectional energy transfer. By optimizing the switching timing and duty cycle of the switching tubes, a higher conversion efficiency can be achieved and energy loss can be reduced.

[0135] In some embodiments, one end of the first primary capacitor 3412 is connected to the positive pole of the first terminal 10, and the other end is respectively connected to the negative pole of the first terminal 10 through the third switch 43 and to the second primary capacitor 3422 through the second switch 42.

[0136] One end of the second primary capacitor 3422 is connected to the negative pole of the first terminal 10, and the other end is respectively connected to the positive pole of the first terminal 10 through the first switch 41 and to the first primary capacitor 3412 through the second switch 42.

[0137] One end of the first secondary capacitor 3512 is connected to the positive pole of the second terminal 20, and the other end is respectively connected to the negative pole of the second terminal 20 through the sixth switch 53 and to the second secondary capacitor 3522 through the fifth switch 52.

[0138] One end of the second secondary capacitor 3522 is connected to the negative pole of the second terminal 20, and the other end is respectively connected to the positive pole of the second terminal 20 through the fourth switch 51 and to the first secondary capacitor 3512 through the fifth switch 52.

[0139] Thus, the first primary-side capacitor 3412, the second primary-side capacitor 3422, the first secondary-side capacitor 3512, and the second secondary-side capacitor 3522 can be used to smooth the pulsation and noise of the output voltage, making the output voltage more stable.

[0140] Specifically, during the off period of the switching transistor, the first primary-side capacitor 3412, the second primary-side capacitor 3422, the first secondary-side capacitor 3512, and the second secondary-side capacitor 3522 can store energy, providing a continuous current supply for the load. Using capacitors at the first terminal 10 can filter out high-frequency noise and interference in the input voltage.

[0141] In some embodiments, the first switch 41, the second switch 42, the third switch 43, the fourth switch 51, the fifth switch 52, and / or the sixth switch 53 are high-frequency switching switches.

[0142] Thus, the output voltage of the high-frequency switching power supply has high stability, is not easily affected by changes in the input voltage and load, and has higher energy conversion efficiency.

[0143] Specifically, in the embodiments of the present application, the first switch 41, the second switch 42, the third switch 43, the fourth switch 51, the fifth switch 52, and the sixth switch 53 are all high-frequency switches. In other embodiments, the first switch 41, the second switch 42, the third switch 43, the fourth switch 51, the fifth switch 52, and the sixth switch 53 can also be set as other non-high-frequency switches, which can be specifically selected and used according to actual needs and will not be elaborated here. However, it should be noted that the switching frequency of the non-high-frequency switch is relatively low. Therefore, when designing the circuit, appropriate values need to be selected according to the switching frequency range of the non-high-frequency switch. The lower switching frequency may affect the response speed and efficiency of the circuit, so comprehensive consideration is required.

[0144] In some embodiments, the first switch 41, the second switch 42, the third switch 43, the fourth switch 51, the fifth switch 52, and / or the sixth switch 53 are any one of MOS transistors, IGBTs, or relays.

[0145] Thus, selecting MOS transistors, IGBTs, or relays for the first switch 41, the second switch 42, the third switch 43, the fourth switch 51, the fifth switch 52, and the sixth switch 53 can be respectively applicable to different usage scenarios, which is beneficial to broadening the usage range of the bidirectional DC power converter 100.

[0146] Specifically, the first switch 41, the second switch 42, the third switch 43, the fourth switch 51, the fifth switch 52, and the sixth switch 53 can select any one or two of MOS transistors, IGBTs, or relays. Specifically, which high-frequency switch is selected for the first switch 41, the second switch 42, the third switch 43, the fourth switch 51, the fifth switch 52, and the sixth switch 53 can be selected according to actual usage requirements.

[0147] In some embodiments, the bidirectional DC power converter 100 further includes a voltage detection circuit 70, and the voltage detection circuit 70 is connected in parallel to the first end 10 and / or the second end 20.

[0148] In this way, the voltage of the first end 10 and the second end 20 can be detected at any time through the voltage detection circuit 70 to avoid excessive voltage.

[0149] Specifically, the voltage detection circuit 70 is an electronic circuit used to monitor and measure the voltage level in a circuit. This kind of circuit is widely used in various electronic devices, power management systems, protection circuits, and automatic control systems to ensure that the device operates within the correct voltage range and prevent damage or failure caused by overvoltage or undervoltage.

[0150] In the embodiment of the present application, the number of the voltage detection circuits 70 is two, and the two voltage detection circuits 70 are respectively connected in parallel to the first end 10 and the second end 20.

[0151] Please refer to Figure 4 , in some embodiments, the voltage detection circuit 70 includes an operational amplifier 71 and several resistors 72 connected in series. Two input terminals of the operational amplifier 71 are connected to both ends of any one resistor 72, and the output terminal of the operational amplifier 71 is connected to the controller 60.

[0152] In this way, the voltage of the first end 10 and the second end 20 is detected through the operational amplifier 71 and the controller 60, which is beneficial to reacting more promptly to problems such as excessive voltage.

[0153] Specifically, the operational amplifier 71 is a circuit unit named from a functional perspective, which has multiple functions such as amplification, summation, and integration, and can jointly form a certain functional module in combination with a feedback network.

[0154] In the embodiment of the present application, it includes a first resistor, a second resistor, and a third resistor connected in series. The operational amplifier 71 is connected in parallel to both ends of the first resistor and is connected to the controller 60.

[0155] In other embodiments, the operational amplifier 71 can also be connected in parallel to both ends of other resistors 72.

[0156] Please refer to Figure 5, in some embodiments, the voltage detection circuit 70 includes an isolator 73, an operational amplifier 71, and a plurality of resistors 72 connected in series. The isolator 73 is connected in parallel with any one of the resistors 72. The output end of the isolator 73 is connected to the operational amplifier 71, and the output end of the operational amplifier 71 is connected to the controller 60.

[0157] In this way, the isolator 73 can reduce the errors caused by signal interference and leakage, and improve the accuracy and reliability of sampling.

[0158] Specifically, the isolator 73 is a device that uses the principle of linear optocoupler isolation or other physical effects (such as electromagnetic induction, photoelectric conversion, etc.) to convert the input signal and output it, while realizing the mutual isolation among the input, output, and working power supply.

[0159] In the embodiment of the present application, it includes a first resistor, a second resistor, and a third resistor connected in series. The isolator 73 is connected in parallel across the first resistor and is connected to the operational amplifier 71, and the operational amplifier 71 is then connected to the controller 60.

[0160] In other embodiments, the operational amplifier 71 can also be connected in parallel across other resistors 72.

[0161] Please refer to Figure 2 and Figure 3 , in some embodiments, the controller 60 is configured to control the first switch 41 and the third switch 43 to be turned off and the second switch 42 to be turned on when the voltage at the first end 10 is greater than a predetermined voltage.

[0162] In this way, when the voltage at the first end 10 is high, the first primary DCDC circuit 341 and the second primary DCDC circuit 342 at the first end 10 form a voltage dividing circuit to avoid damage to electrical components caused by excessive voltage.

[0163] Specifically, in the embodiment of the present application, the predetermined voltage is 500V.

[0164] When it is detected that the voltage at the first end 10 is greater than 500V, the controller 60 controls the second switch 42 to be turned on and controls the first switch 41 and the third switch 43 to be turned off, so that the first primary DCDC circuit 341 and the second primary DCDC circuit 342 work in series to form a voltage dividing circuit. The voltage of the first primary DCDC circuit 341 plus the voltage of the second primary DCDC circuit 342 is equal to the input voltage. The voltage of the first primary DCDC circuit 341 is reduced by half relative to the input voltage, and the voltage of the second primary DCDC circuit 342 is also reduced by half relative to the input voltage, thus avoiding damage to electrical components caused by excessive voltage.

[0165] Further, after series voltage division, the breakdown voltage ratings of the switching transistors in the first primary full-bridge circuit 3411 and the second primary full-bridge circuit 3421 of the primary DCDC circuit 34 can be relatively halved, and the breakdown voltage ratings of the first primary capacitor 3412 and the second primary capacitor 3422 can also be relatively halved. In this way, the bidirectional DC power converter 100 can select power devices with relatively lower breakdown voltage ratings, greatly reducing the cost of the bidirectional DC power converter 100.

[0166] In some embodiments, the controller 60 is configured to control the second switch 42 to turn off and the first switch 41 and the third switch 43 to turn on when the voltage at the first terminal 10 is less than or equal to a predetermined voltage.

[0167] In this way, when the voltage at the first terminal 10 is low, the current at the first terminal 10 is large at this time, and the first primary DCDC circuit 341 and the second primary DCDC circuit 342 at the first terminal 10 form a shunt circuit to avoid damage to electrical components caused by excessive current.

[0168] Specifically, in the embodiments of the present application, the predetermined voltage is 500V.

[0169] When it is detected that the first terminal 10 is less than or equal to 500V, the controller 60 controls the first switch 41 and the third switch 43 to turn on and controls the second switch 42 to turn off, so that the first primary DCDC circuit 341 and the second primary DCDC circuit 342 operate in parallel to form a shunt circuit. The current of the first primary DCDC circuit 341 is reduced by half relative to the input current, and the current of the second primary DCDC circuit 342 is also reduced by half relative to the input current, thereby avoiding damage to electrical components caused by excessive current. And since the input current is equal to the sum of the current of the first primary DCDC circuit 341 and the current of the second primary DCDC circuit 342, the total input current of the first primary DCDC circuit 341 and the second primary DCDC circuit 342 increases by a factor of two, and the input power also increases by a factor of two.

[0170] In some embodiments, the controller 60 is configured to control the fourth switch 51 and the sixth switch 53 to turn off and the fifth switch 52 to turn on when the voltage at the second terminal 20 is greater than the predetermined voltage.

[0171] In this way, when the voltage at the second terminal 20 is high, the first secondary DCDC circuit 351 and the second secondary DCDC circuit 352 at the second terminal 20 both form voltage-dividing circuits to avoid damage to electrical components caused by excessive voltage.

[0172] Specifically, in the embodiments of the present application, the predetermined voltage is 500V.

[0173] When it is detected that the voltage of the second terminal 20 is greater than 500V, the controller 60 controls the fifth switch 52 to conduct and controls the fourth switch 51 and the sixth switch 53 to disconnect, so that the first secondary DCDC circuit 351 and the second secondary DCDC circuit 352 are connected in series to form a voltage dividing circuit. The voltage of the first secondary DCDC circuit 351 plus the voltage of the second secondary DCDC circuit 352 is equal to the output voltage. The voltage of the first secondary DCDC circuit 351 is reduced by half relative to the output voltage, and the voltage of the second secondary DCDC circuit 352 is also reduced by half relative to the output voltage, thereby avoiding damage to electrical components caused by excessive voltage.

[0174] Furthermore, after series voltage division, the withstand voltage ratings of the switching tubes in the first secondary full-bridge circuit 3511 and the second secondary full-bridge circuit 3521 in the secondary DCDC circuit 35 can be relatively halved, and the withstand voltage ratings of the first secondary capacitor 3512 and the second secondary capacitor 3522 can also be relatively halved. In this way, the bidirectional DC-DC power converter 100 can select power devices with relatively lower withstand voltage ratings, greatly reducing the cost of the bidirectional DC-DC power converter 100.

[0175] In some embodiments, the controller 60 is configured to control the fifth switch 52 to disconnect and the fourth switch 51 and the sixth switch 53 to conduct when the voltage of the second terminal 20 is less than or equal to the predetermined voltage.

[0176] In this way, when the voltage of the second terminal 20 is low, the current of the second terminal 20 is large at this time, and the second terminal 20, the first secondary DCDC circuit 351, and the second secondary DCDC circuit 352 form a shunt circuit to avoid damage to electrical components caused by excessive current.

[0177] Specifically, in the embodiment of the present application, the predetermined voltage is 500V.

[0178] When it is detected that the voltage of the second terminal 20 is less than or equal to 500V, the controller 60 controls the fourth switch 51 and the sixth switch 53 to conduct and controls the fifth switch 52 to disconnect, so that the first secondary DCDC circuit 351 and the second secondary DCDC circuit 352 are connected in parallel to form a shunt circuit. The voltage of the first secondary DCDC circuit 351 is reduced by half relative to the output current, and the voltage of the second secondary DCDC circuit 352 is also reduced by half relative to the output current, thereby avoiding damage to electrical components caused by excessive current. And since the output current is equal to the sum of the current of the first secondary DCDC circuit 351 and the current of the second secondary DCDC circuit 352, the total output current of the first secondary DCDC circuit 351 and the second secondary DCDC circuit 352 increases by a factor of two, and the output power also increases by a factor of two.

[0179] In some embodiments, the primary resonant network 36 includes a first capacitor 364 and a first inductor 363 that are connected in series between the primary DCDC circuit 34 and the primary side of the transformer 33 in sequence;

[0180] The secondary resonant network 37 includes a second inductor 373 and a second capacitor 374 that are connected in series between the secondary DCDC circuit 35 and the secondary side of the transformer 33 in sequence.

[0181] In this way, the primary resonant network 36 and the secondary resonant network 37 can utilize the energy storage characteristics of inductors and capacitors to achieve resonance through the alternating conversion of electromagnetic energy.

[0182] Specifically, both the first primary resonant network 361 and the second primary resonant network 362 include a first inductor 363 and a first capacitor 364 connected in series; both the first secondary resonant network 371 and the second secondary resonant network 372 include a second inductor 373 and a second capacitor 374 connected in series. Among them, the first inductor 363 and the second inductor 373 store energy by generating magnetic fields and release this energy when needed. This energy storage characteristic enables the first inductor 363 and the second inductor 373 to smoothly adjust the changes in current and voltage during the resonance process. The first capacitor 364 and the second capacitor 374 control the changes in current and voltage in the circuit by storing and releasing charges. When the voltage in the circuit changes, the capacitor absorbs or releases charges to maintain the stability of the voltage.

[0183] Furthermore, the first inductor 363 and the first capacitor 364 of the primary resonant network 36 can be connected in series on the same side of the primary side of the transformer 33, and there are no excessive restrictions on the connection order of the first inductor 363 and the first capacitor 364. Similarly, the second inductor 373 and the second capacitor 374 of the secondary resonant network 37 can be connected in series on the same side of the secondary side of the transformer 33, and there are also no excessive restrictions on the connection order of the second inductor 373 and the second capacitor 374.

[0184] In some embodiments, the first inductor 363 and the first capacitor 364 of the primary resonant network 36 can also be connected in series on both sides of the primary side of the transformer 33. Similarly, the second inductor 373 and the second capacitor 374 of the secondary resonant network 37 can also be connected in series on both sides of the secondary side of the transformer 33.

[0185] In some embodiments, the present application further provides an energy storage power supply system, which includes: at least one battery pack and an inverter, wherein the at least one battery pack is used to store or output electric energy, and the inverter integrates the bidirectional DC power conversion circuit described in any one of the above. In some embodiments, the inverter further includes a DC / AC bidirectional conversion circuit, which is used to convert direct current into alternating current, such as converting the direct current in the battery pack into alternating current and outputting it externally, and / or, which is used to convert alternating current into direct current, such as converting the mains power into direct current and storing it in the at least one battery pack.

[0186] In some embodiments, the bidirectional DC power conversion circuit is configured such that when the energy storage power supply system charges an electric vehicle, the power flow direction of the bidirectional DC power conversion circuit is from the first end 10 to the second end 20, and when the electric vehicle charges the energy storage power supply system, the power flow direction of the bidirectional DC power conversion circuit is from the second end 20 to the first end 10.

[0187] In this way, the first end 10 can be connected to the input end of the DC charging pile 1000, and the second end 20 can be connected to the output end of the DC charging pile 1000.

[0188] Specifically, in the embodiments of the present application, the first end 10 is used as the input end, the second end 20 is used as the output end, and the power flow direction of the bidirectional DC power conversion circuit 100 is from the first end 10 to the second end 20. In other embodiments, the second end 20 can also be used as the input end and the first end 10 can be used as the output end. At this time, the power flow direction of the bidirectional DC power conversion circuit 100 is from the second end 20 to the first end 10.

[0189] In some embodiments, the energy storage power supply system is a household energy storage power supply system or can also be a balcony photovoltaic energy storage system. Among them, the household energy storage power supply system is usually relatively large, its installed position is relatively fixed and immovable, its capacitance is relatively large, and the power provided is relatively large; while the balcony photovoltaic energy storage power supply system is relatively miniaturized and easy to carry and move, and its position can be transferred according to the user's electricity demand, for example, transferred from the balcony position to the garage or even outdoors, etc., its capacitance is relatively small, and the power provided is also relatively small.

[0190] In the description of this specification, the description with reference to the terms "certain embodiments", "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0191] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of the said features. In the description of the present application, "a plurality of" means at least two, such as two, three, unless otherwise specifically defined.

[0192] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A bidirectional DC power converter, characterized in that: include: First end; The second end; At least two bidirectional DCDC units, each of the bidirectional DCDC units comprising a transformer, a primary DCDC circuit and a primary resonant network sequentially connected between the first end and the primary side of the transformer, and a secondary DCDC circuit and a secondary resonant network sequentially connected between the second end and the secondary side of the transformer; A primary switch connected in parallel with the primary resonant network and between the primary DCDC circuit and the primary side of the transformer; A secondary switch connected in parallel with the secondary resonant network and between the secondary DCDC circuit and the secondary side of the transformer; a first switch circuit connected between the first end and the primary DCDC circuit; a second switch circuit connected between the second end and the secondary side DCDC circuit; The controller is configured to control the on-off of the switch in the first switch circuit so that the primary DCDC circuits of the at least two bidirectional DCDC units are connected in series or in parallel, and / or control the on-off of the switch in the second switch circuit so that the secondary DCDC circuits of the at least two bidirectional DCDC units are connected in series or in parallel and control the on-off of the primary switch and the secondary switch.

2. The bidirectional DC power converter according to claim 1, characterized in that: The primary resonant network comprises a first capacitor and a first inductor connected in series between the primary DCDC circuit and the primary side of the transformer; The secondary resonant network includes a second inductor and a second capacitor which are sequentially connected in series between the secondary DCDC circuit and the secondary side of the transformer.

3. The bidirectional DC power converter according to claim 1, characterized in that: The primary switch and the secondary switch are high-frequency switching switches.

4. The bidirectional DC power converter according to claim 3, characterized in that: The primary switch and the secondary switch are any one of a MOS tube, an IGBT or a relay.

5. The bidirectional DC power converter according to claim 1, characterized in that: The controller is used to control the primary switch to be disconnected and the secondary switch to be disconnected, so that the bidirectional DC power converter operates in an asymmetric CLLC mode.

6. The bidirectional DC power converter according to claim 1, characterized in that: The controller is used to control the primary switch to be disconnected and the secondary switch to be turned on, so that the bidirectional DC power converter operates in a forward LLC mode.

7. The bidirectional DC power converter according to claim 1, characterized in that: The controller is used to control the primary switch to be turned on and the secondary switch to be turned on, so that the bidirectional DC power converter operates in a full-bridge circuit mode.

8. The bidirectional DC power converter according to claim 1, characterized in that: The controller is used to control the primary switch to be turned on and the secondary switch to be turned off, so that the bidirectional DC power converter operates in a reverse LLC mode.

9. The bidirectional DC power converter according to claim 1, characterized in that: The bidirectional DC power converter comprises a first bidirectional DCDC unit and a second bidirectional DCDC unit, wherein the first bidirectional DCDC unit comprises a first transformer, a first primary DCDC circuit and a first primary resonant network sequentially connected between the first end and the primary side of the first transformer, and a first secondary DCDC circuit and a first secondary resonant network sequentially connected between the second end and the secondary side of the first transformer; The second bidirectional DCDC unit includes a second transformer, a second primary DCDC circuit and a second primary resonant network connected in sequence between the first end and the primary side of the second transformer, and a second secondary DCDC circuit and a second secondary resonant network connected in sequence between the second end and the secondary side of the second transformer.

10. The bidirectional DC power converter according to claim 9, characterized in that: The first switch circuit includes a first switch connected between the positive electrode of the first end and the second primary DCDC circuit, a second switch connected between the first primary DCDC circuit and the second primary DCDC circuit, and a third switch connected between the negative electrode of the first end and the first primary DCDC circuit; The second switch circuit includes a fourth switch connected between the positive electrode of the second end and the second secondary DCDC circuit, a fifth switch connected between the first secondary DCDC circuit and the second secondary DCDC circuit, and a sixth switch connected between the negative electrode of the second end and the first secondary DCDC circuit.

11. The bidirectional DC power converter according to claim 10, characterized in that: The first primary DCDC circuit comprises a first primary full-bridge circuit and a first primary capacitor connected in parallel, two ends of the first primary full-bridge circuit are connected to two ends of the first primary capacitor, the other two ends of the first primary full-bridge circuit are connected to two electrodes of the primary side of the first transformer, and the first primary capacitor is connected to the positive and negative electrodes of the first end; The second primary DCDC circuit comprises a second primary full-bridge circuit and a second primary capacitor connected in parallel, two ends of the second primary full-bridge circuit are connected to two ends of the second primary capacitor, the other two ends of the second primary full-bridge circuit are connected to two electrodes of the primary side of the second transformer, and the second primary capacitor is connected to the positive and negative electrodes of the first end; The first secondary DCDC circuit comprises a first secondary full-bridge circuit and a first secondary capacitor connected in parallel, two ends of the first secondary full-bridge circuit are connected to two ends of the first secondary capacitor, the other two ends of the first secondary full-bridge circuit are connected to two electrodes of the secondary side of the first transformer, and the first secondary capacitor is connected to the positive and negative electrodes of the second end; The second secondary DCDC circuit includes a second secondary full-bridge circuit and a second secondary capacitor connected in parallel, two ends of the second secondary full-bridge circuit are connected to two ends of the second secondary capacitor, the other two ends of the second secondary full-bridge circuit are connected to two electrodes of the secondary side of the second transformer, and the second secondary capacitor is connected to the positive and negative poles of the second end.

12. The bidirectional DC power converter according to claim 11, characterized in that: One end of the first primary capacitor is connected to the positive electrode of the first end, and the other end is connected to the negative electrode of the first end through the third switch and to the second primary capacitor through the second switch; One end of the second primary capacitor is connected to the negative electrode of the first end, and the other end is connected to the positive electrode of the first end through the first switch and to the first primary capacitor through the second switch; One end of the first secondary capacitor is connected to the positive electrode of the second end, and the other end is connected to the negative electrode of the second end through the sixth switch and to the second secondary capacitor through the fifth switch; One end of the second secondary capacitor is connected to the negative electrode of the second end, and the other end is connected to the positive electrode of the second end through the fourth switch and to the first secondary capacitor through the fifth switch.

13. The bidirectional DC power converter according to claim 10, characterized in that: The first switch, the second switch, the third switch, the fourth switch, the fifth switch and / or the sixth switch are high-frequency switching switches.

14. The bidirectional DC power converter according to claim 13, characterized in that: The first switch, the second switch, the third switch, the fourth switch, the fifth switch and / or the sixth switch are any one of MOS tubes, IGBTs or relays.

15. The bidirectional DC power converter according to claim 10, characterized in that: The bidirectional DC power converter further includes a voltage detection circuit, and the voltage detection circuit is connected in parallel to the first end and / or the second end.

16. The bidirectional DC power converter according to claim 15, characterized in that: The voltage detection circuit includes an operational amplifier and a plurality of resistors connected in series, wherein two input terminals of the operational amplifier are connected to two ends of any one of the resistors, and an output terminal of the operational amplifier is connected to the controller.

17. The bidirectional DC power converter according to claim 15, characterized in that: The voltage detection circuit includes an isolator, an operational amplifier and a plurality of resistors connected in series, the isolator is connected in parallel with any one of the resistors, the output end of the isolator is connected to the operational amplifier, and the output end of the operational amplifier is connected to the controller.

18. The bidirectional DC power converter according to claim 10, characterized in that: The controller is configured to control the first switch and the third switch to be turned off and the second switch to be turned on when the voltage at the first end is greater than a predetermined voltage.

19. The bidirectional DC power converter according to claim 10, characterized in that: The controller is configured to control the second switch to be turned off and the first switch and the third switch to be turned on when the voltage at the first end is less than or equal to a predetermined voltage.

20. The bidirectional DC power converter according to claim 10, characterized in that: The controller is configured to control the fourth switch and the sixth switch to be turned off and the fifth switch to be turned on when the voltage at the second end is greater than a predetermined voltage.

21. The bidirectional DC power converter according to claim 10, characterized in that: The controller is configured to control the fifth switch to be turned off and the fourth switch and the sixth switch to be turned on when the voltage at the second end is less than or equal to a predetermined voltage.

22. The bidirectional DC power converter according to claim 1, characterized in that: The primary resonant network comprises a first capacitor and a first inductor connected in series between the primary DCDC circuit and the primary side of the transformer; The secondary resonant network includes a second inductor and a second capacitor which are sequentially connected in series between the secondary DCDC circuit and the secondary side of the transformer.

23. A DC charging pile, characterized in that: include: A charging gun, which is used to connect to an electric vehicle; The bidirectional DC power converter according to any one of claims 1 to 22, wherein the first end is connected to the energy storage power supply system, and the second end is connected to the charging gun.

24. The DC charging pile according to claim 23, characterized in that: The bidirectional DC power converter is configured so that when the energy storage power supply system charges the electric vehicle, the power of the bidirectional DC power converter 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 bidirectional DC power converter flows from the second end to the first end.

25. An energy storage power supply 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; An inverter, wherein the inverter integrates the bidirectional DC power converter according to any one of claims 1 to 22.

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