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

Abstract

The utility model discloses a bidirectional DC power conversion circuit and a DC charging pile, and the circuit comprises a first end, a second end, a transformer, and a first DCDC circuit and a first resonant network which are sequentially connected between the first end and the primary side of the transformer. The first switch is connected between the first DCDC circuit and the primary side of the transformer, the second DCDC circuit and the second resonance network are sequentially connected between the second end and the secondary side of the transformer, and the second switch and the controller are connected with the second resonance network in parallel and connected between the second DCDC circuit and the secondary side of the transformer. The switch is configured to control on-off of the first switch and the second switch. According to the bidirectional direct-current power conversion circuit provided by the invention, the on-off of the first switch and the second switch can be controlled through the controller, and the topological structure is changed, so that the bidirectional direct-current power conversion circuit can be suitable for different scenes. Therefore, the voltage regulation capability of the bidirectional direct-current power conversion circuit is improved, and the conversion efficiency is ensured.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and more particularly, to a bidirectional DC power conversion circuit, a DC charging pile, and an energy storage power supply device. Background Art

[0002] Bidirectional DC power conversion circuits have various topological structures and are applicable to 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 conversion circuit with the same topological structure 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 this application provide a bidirectional DC power conversion circuit and a DC charging pile.

[0004] The bidirectional DC power conversion circuit according to the embodiments of this application includes:

[0005] A first end;

[0006] A second end;

[0007] A transformer;

[0008] A first DCDC circuit and a first resonant network connected in sequence between the first end and the primary side of the transformer;

[0009] A first switch connected in parallel with the first resonant network and between the first DCDC circuit and the primary side of the transformer;

[0010] A second DCDC circuit and a second resonant network connected in sequence between the second end and the secondary side of the transformer;

[0011] A second switch connected in parallel with the second resonant network and between the second DCDC circuit and the secondary side of the transformer;

[0012] A controller configured to control the on / off states of the first switch and the second switch.

[0013] The bidirectional DC power conversion circuit provided by this application can control the on / off states of the first switch and the second switch through the controller, changing the topological structure of the bidirectional DC power conversion circuit. Therefore, the bidirectional DC power conversion circuit can be applicable to different scenarios, thereby improving the voltage regulation ability of the bidirectional DC power conversion circuit and ensuring the conversion efficiency.

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

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

[0016] In this way, the resonant network of the single C structure may generate a resonance phenomenon under specific conditions (such as when interacting with other components or systems), which can reduce the number of components and cost while meeting the usage requirements.

[0017] In some embodiments, one end of the first switch is connected to the end of the first capacitor away from the first inductor, and the other end is connected to the end of the first inductor away from the first capacitor. Both ends of the second switch are respectively connected to both ends of the second capacitor.

[0018] In this way, the first switch can be used to control the access of the first inductor and the first capacitor, and the second switch can be used to control the access of the second capacitor.

[0019] In some embodiments, the first resonant network includes a first capacitor and a first inductor connected in series between the first DCDC circuit and the primary side of the transformer in sequence;

[0020] The second resonant network includes a second inductor and a second capacitor connected in series between the second DCDC circuit and the secondary side of the transformer in sequence.

[0021] In this way, the first resonant network and the second resonant network can utilize the energy storage characteristics of the inductor and the capacitor to achieve resonance through the alternating conversion of electromagnetic energy.

[0022] In some embodiments, one end of the first switch is connected to the end of the first capacitor away from the first inductor, and the other end is connected to the end of the first inductor away from the first capacitor. One end of the second switch is connected to the end of the second capacitor away from the second inductor, and the other end is connected to the end of the second inductor away from the second capacitor.

[0023] In this way, the first switch can be used to control the access of the first inductor and the first capacitor, and the second switch can be used to control the access of the second inductor and the second capacitor.

[0024] In some embodiments, the first switch and the second switch are high-frequency switching switches.

[0025] In this way, the output voltage of the high-frequency switching power supply has high stability, is not easily affected by the input voltage and load changes, and has higher energy conversion efficiency.

[0026] In some embodiments, the first switch and the second switch are any one of MOS transistors, IGBTs or relays.

[0027] In this way, the first switch and the second switch select MOS transistors, IGBTs or relays, which can be respectively applicable to different usage scenarios, facilitating the expansion of the usage range of the bidirectional DC power conversion circuit.

[0028] In some embodiments, the controller is configured to control the first switch to turn off and the second switch to turn off, so that the bidirectional DC power conversion circuit operates in the asymmetric CLLC mode.

[0029] In this way, enabling the bidirectional DC power conversion circuit to operate in the CLLC mode can achieve bidirectional power flow of electric energy, which is beneficial to obtaining a high power conversion efficiency.

[0030] In some embodiments, the controller is configured to control the first switch to turn off and the second switch to turn on, so that the bidirectional DC power conversion circuit operates in the LLC mode.

[0031] In this way, enabling the bidirectional DC power conversion circuit 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.

[0032] In some embodiments, the controller is configured to control the first switch to turn on and the second switch to turn on, so that the bidirectional DC power conversion circuit operates in the full-bridge circuit mode.

[0033] In this way, enabling the bidirectional DC power conversion circuit to operate in the full-bridge circuit mode facilitates handling a large current and meeting the application scenarios of high-power output.

[0034] In some embodiments, the controller is configured to control the first switch to turn on and the second switch to turn off, so that the bidirectional DC power conversion circuit operates in the phase-shift mode.

[0035] In this way, enabling the bidirectional DC power conversion circuit to operate in the phase-shift mode is beneficial to improving the conversion efficiency, reducing energy loss and decreasing the volume, being applicable to the application scenarios that require precise control and regulation. In addition, the phase-shift mode has advantages when a wide range of output voltage regulation is needed.

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

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

[0038] In this way, the first DCDC circuit and the second DCDC circuit are used to achieve the conversion of electrical energy, and can also balance the supply-demand relationship to a certain extent, improving the overall stability and reliability.

[0039] In some embodiments, the first terminal is configured to be connected to an energy storage power supply system, and is used to receive electrical energy from the energy storage power supply system or deliver electrical energy to the energy storage power supply system.

[0040] The second terminal is configured to be connected to a charging gun, and is used to receive electrical energy from an electric vehicle through the charging gun or deliver electrical energy to the electric vehicle through the charging gun.

[0041] In this way, the first terminal can be used as the input terminal of the bidirectional DC power conversion circuit, and the second terminal can be used as the output terminal of the bidirectional DC power conversion circuit.

[0042] A DC charging pile according to another embodiment of the present application includes:

[0043] A charging gun for connecting to an electric vehicle;

[0044] The bidirectional DC power conversion circuit according to any one of the above, where the first terminal is connected to an energy storage power supply system, and the second terminal is connected to the charging gun.

[0045] In some embodiments, 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 terminal to the second terminal. 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 terminal to the first terminal.

[0046] In this way, the first terminal can be connected to the input terminal of the DC charging pile, and the second terminal can be connected to the output terminal of the DC charging pile.

[0047] An energy storage power supply system according to another embodiment of the present application includes:

[0048] At least one battery pack for storing or outputting electrical energy;

[0049] An inverter, the inverter integrating the bidirectional DC power conversion circuit described in any one of the above. Additional aspects and advantages of the embodiments of the present application will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the embodiments of the present application. Brief Description of the Drawings

[0050] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0051] Figure 1 is a schematic diagram of the modules of the DC charging pile and the bidirectional DC power conversion circuit according to the embodiments of the present application;

[0052] Figure 2 is a circuit diagram of the bidirectional DC power conversion circuit according to some embodiments of the present application;

[0053] Figure 3 is a circuit diagram of the bidirectional DC power conversion circuit according to some embodiments of the present application.

[0054] Main element symbol description: DC charging pile 1000, bidirectional DC power conversion circuit 100, first end 10, second end 20, transformer 30, first resonant network 40, first switch 41, first inductor 42, first capacitor 43, second resonant network 50, second switch 51, second capacitor 52, first DCDC circuit 60, first full-bridge circuit 61, third capacitor 62, second DCDC circuit 70, second full-bridge circuit 71, fourth capacitor 72, controller 80, charging gun 200. Detailed Embodiments

[0055] The following describes in detail the embodiments of the present application. The examples of the embodiments are shown in the 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 with reference to the drawings are exemplary and are only used to explain the present application and should not be construed as a limitation of the present application. In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "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 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 a limitation of the present application. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0056] In the description of the present application, it should be noted that unless otherwise clearly specified or limited, the terms "installed", "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. It may be the communication inside two components or the interaction relationship between two components. 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.

[0057] In the present application, unless otherwise clearly specified or limited, 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 indicates 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 indicates that the horizontal height of the first feature is lower than that of the second feature.

[0058] The present disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described herein. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples. Such 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, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0059] With the development and popularization of new energy vehicle technologies, the charging pile industry has been vigorously promoted. The battery voltage range has gradually expanded, and DC charging equipment needs to meet the charging requirements of different types of vehicle batteries. As an emerging development direction and trend, V2G has received increasing attention and emphasis.

[0060] Bidirectional DC power conversion circuits have various topological structures and are applicable to 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 technologies, bidirectional DC power conversion circuits of the same topological structure 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.

[0061] Please refer to Figure 1, an embodiment of the present application provides a DC charging pile 1000, including a charging gun 200 for connecting to an electric vehicle and a bidirectional DC power conversion circuit 100. The first end 10 is connected to an energy storage power system, and the second end 20 is connected to the charging gun 200.

[0062] The bidirectional DC power conversion circuit 100 includes a first end 10, a second end 20, a transformer 30, a first DCDC circuit 60 and a first resonant network 40 connected in sequence between the first end 10 and the primary side of the transformer 30, a first switch 41 connected in parallel with the first resonant network 40 and between the first DCDC circuit 60 and the primary side of the transformer 30, a second DCDC circuit 70 and a second resonant network 50 connected in sequence between the second end 20 and the secondary side of the transformer 30, a second switch 51 connected in parallel with the second resonant network 50 and between the second DCDC circuit 70 and the secondary side of the transformer 30, and a controller 80 configured to control the on / off of the first switch 41 and the second switch 51.

[0063] The bidirectional DC power conversion circuit 100 provided by the present application can control the on / off of the first switch 41 and the second switch 51 through the controller 80 to change the topology of the bidirectional DC power conversion circuit 100. Therefore, the bidirectional DC power conversion circuit 100 can be applicable to different scenarios, thereby improving the voltage regulation ability of the bidirectional DC power conversion circuit 100 and ensuring the conversion efficiency.

[0064] Specifically, the transformer 30 generally refers to a power electronic component that can achieve electrical isolation and voltage conversion. This transformer 30 plays an important role in the bidirectional DC converter. Through the magnetic coupling effect of its windings, the transformer 30 realizes the electrical isolation between the first end 10 and the second end 20, thereby improving the safety and reliability of the system. At the same time, it also has the ability to transform voltage. According to the turns ratio of the transformer 30 (i.e., the ratio of the number of turns of the primary winding to the number of turns of the secondary winding), the transformer 30 can convert one DC voltage into another DC voltage to meet the different requirements of the circuit, enabling the circuit to flexibly handle DC power with different voltage levels.

[0065] The primary side (also known as the primary side or input side) refers to the side directly connected to the power supply, that is, the first end 10 of the electric energy. The primary side is connected to the power supply through wires or coils, receives electrical energy from the power supply, and converts it into magnetic energy (through the magnetic field generated by the current in the wire). During the operation of the transformer 30, this magnetic energy will cross the iron core or magnetic core of the transformer 30 and be transferred to the secondary side (secondary side or output side) through mutual inductance.

[0066] The secondary side (also known as the secondary or output side) refers to the side directly connected to the load, i.e., the second terminal 20 of the electrical energy. The secondary side receives electrical energy transferred through magnetic field induction from the primary side (primary or input side) via wires or coils and converts it into the form of voltage and current required by the load.

[0067] In the embodiments of the present application, the first switch 41 is connected in parallel with the first resonant network 40. When the first switch 41 is closed, the first resonant network 40 is short-circuited by the first switch 41. At this time, it is equivalent to removing the first resonant network 40 from the circuit. Similarly, the second switch 51 is connected in parallel with the second resonant network 50. When the second switch 51 is closed, the second resonant network 50 is short-circuited by the second switch 51. At this time, it is equivalent to removing the second resonant network 50 from the circuit.

[0068] Furthermore, the controller 80 is used to control the closing and opening of the first switch 41 and the second switch 51. In some embodiments, the controller 80 can be a Programmable Logic Controller (PLC). A programmable logic controller is a digital operation controller with a microprocessor for automation control. It uses a programmable memory to store instructions for performing operations such as logical operations, sequential control, timing, counting, and arithmetic operations inside it. These instructions control various types of mechanical equipment or production processes through digital or analog inputs and outputs. The operator can store the algorithm logic in the controller 80 in advance and control the closing and opening of the first switch 41 and the second switch 51 through the controller 80.

[0069] In other embodiments, the controller 80 can also be set to other elements with the same function, which can be specifically selected according to the actual situation and will not be elaborated here.

[0070] Please refer to Figure 3 , in some embodiments, the first resonant network 40 includes a first capacitor 43 and a first inductor 42 connected in series between the first DCDC circuit 60 and the primary side of the transformer 30 in sequence;

[0071] The second resonant network 50 includes a second capacitor 52 connected between the second DCDC circuit 70 and the secondary side of the transformer 30.

[0072] In this way, a resonant network with a single C structure may generate a resonance phenomenon under specific conditions (such as when interacting with other components or systems), which can reduce the number of components and lower the cost while meeting the usage requirements.

[0073] Specifically, a resonant network is a circuit structure composed of components such as inductors and capacitors. It can generate a resonance phenomenon at a specific frequency, that is, the impedance of the inductor is equal to the impedance of the capacitor and their phases are opposite, thereby achieving the resonance of the circuit. The resonance phenomenon refers to the phase difference between the current and voltage in the circuit reaching the minimum (ideally zero), and at this time, the response of the circuit to the signal reaches the maximum.

[0074] In some embodiments, the first resonant network 40 includes a first inductor 42 and a first capacitor 43 connected in series. Among them, the first inductor 42 stores energy by generating a magnetic field and releases this energy when needed. This energy storage characteristic enables the inductor to smoothly regulate the changes in current and voltage during the resonance process. The first capacitor 43 controls 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.

[0075] In some embodiments, in order to simplify the circuit structure, reduce costs, and decrease the volume, it may be possible to choose to set only one second capacitor 52 in the second resonant network 50. Although such a setting may sacrifice certain filtering effects and dynamic response performance, it can meet specific application requirements.

[0076] In some embodiments, such as when rapid response to load changes or voltage regulation at a specific frequency is required, it may also be possible to set only one second capacitor 52 in the second resonant network 50 to meet the requirements. It should be noted that the selection and parameter design of the second capacitor 52 will be particularly important and require detailed analysis and selection based on specific circuit parameters, component characteristics, and application requirements.

[0077] In some embodiments, one end of the first switch 41 is connected to the end of the first capacitor 43 away from the first inductor 42, and the other end is connected to the end of the first inductor 42 away from the first capacitor 43. Both ends of the second switch 51 are respectively connected to both ends of the second capacitor 52.

[0078] In this way, the first switch 41 can be used to control the access of the first inductor 42 and the first capacitor 43, and the second switch 51 can be used to control the access of the second capacitor 52.

[0079] Specifically, the first inductor 42 and the first capacitor 43 of the first resonant network 40 are connected in series on the same side of the primary side of the transformer 30, and the connection order of the first inductor 42 and the first capacitor 43 is not overly restricted. At this time, one first switch can control the access of the first inductor 42 and the first capacitor 43. Similarly, one second switch can control the access of the second capacitor 52.

[0080] In some embodiments, the first inductor 42 and the first capacitor 43 of the first resonant network 40 may also be connected in series on both sides of the primary side of the transformer 30. At this time, to achieve the short circuit of the first resonant network 40, a first switch 41 should be connected in parallel at both ends of the first inductor 42 and the first capacitor 43, and the two first switches 41 are linked. Similarly, the first inductor 42 and the first capacitor 43 of the second resonant network 50 may also be connected in series on both sides of the primary side of the transformer 30. At this time, to achieve the short circuit of the second resonant network 50, a second switch 51 should be connected in parallel at both ends of the first inductor 42 and the first capacitor 43, and the two second switches 51 are linked.

[0081] Please refer to Figure 2 , in some embodiments, the first resonant network 40 includes a first capacitor 43 and a first inductor 42 connected in series in sequence between the first DCDC circuit 60 and the primary side of the transformer 30;

[0082] The second resonant network 50 includes a second inductor and a second capacitor 52 connected in series in sequence between the second DCDC circuit 70 and the secondary side of the transformer 30.

[0083] In this way, the first resonant network 40 and the second resonant network 50 can utilize the energy storage characteristics of the inductor and the capacitor to achieve resonance through the alternating conversion of electromagnetic energy.

[0084] Specifically, in some embodiments, both the first resonant network 40 and the second resonant network 50 include a first inductor 42 and a first capacitor 43 connected in series. Among them, the first inductor 42 stores energy by generating a magnetic field and releases this energy when needed.

[0085] In some embodiments, one end of the first switch 41 is connected to the end of the first capacitor 43 away from the first inductor 42, and the other end is connected to the end of the first inductor 42 away from the first capacitor 43. One end of the second switch 51 is connected to the end of the second capacitor 52 away from the second inductor, and the other end is connected to the end of the second inductor away from the second capacitor 52.

[0086] In this way, the first switch 41 can be used to control the access of the first inductor 42 and the first capacitor 43, and the second switch 51 can be used to control the access of the second inductor and the second capacitor 52.

[0087] Specifically, the first inductor 42 and the first capacitor 43 of the first resonant network 40 can be connected in series on the same side of the primary of the transformer 30. There is no strict limit on the connection order of the first inductor 42 and the first capacitor 43. Similarly, the first inductor 42 and the first capacitor 43 of the second resonant network 50 can be connected in series on the same side of the secondary of the transformer 30, and there is also no strict limit on the connection order of the first inductor 42 and the first capacitor 43. At this time, a first switch can control the connection of the first inductor 42 and the first capacitor 43 of the first resonant network 40. Similarly, a second switch can control the connection of the first inductor 42 and the first capacitor 43 of the second resonant network 50.

[0088] In some embodiments, the first inductor 42 and the first capacitor 43 of the first resonant network 40 can also be connected in series on both sides of the primary of the transformer 30. At this time, to achieve the short - circuit of the first resonant network 40, a first switch 41 should be connected in parallel at both ends of the first inductor 42 and the first capacitor 43, and the two first switches 41 are set to be linked. Similarly, the first inductor 42 and the first capacitor 43 of the second resonant network 50 can also be connected in series on both sides of the secondary of the transformer 30. At this time, to achieve the short - circuit of the second resonant network 50, a second switch 51 should be connected in parallel at both ends of the first inductor 42 and the first capacitor 43, and the two second switches 51 are set to be linked.

[0089] Please refer to Figure 2 and Figure 3 , in some embodiments, the first switch 41 and the second switch 51 are high - frequency switching switches.

[0090] 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.

[0091] Specifically, in the embodiments of the present application, both the first switch 41 and the second switch 51 are high - frequency switches. A high - frequency switch is an electronic device based on electronic components, and its characteristic is that it uses a high frequency to control the switching of current. Specifically, a high - frequency switch controls the flow of current in the circuit by periodically switching the current, so that it can be quickly switched at a high frequency.

[0092] It is easy to understand that a high - frequency switch can complete the opening and closing actions in an extremely short time, so as to realize the rapid control and conversion of electric energy in the resonant network. This rapid energy conversion helps to improve the overall efficiency of the system. In the bidirectional DC - DC power conversion circuit 100, the load and power supply states may change frequently. The high - frequency switch can quickly respond to these changes, adjust the working state of the circuit by short - circuiting the resonant network to meet the new load or power supply requirements.

[0093] In other embodiments, the first switch 41 and the second switch 51 can also be set as other non-high-frequency switches, which can be specifically selected according to actual needs and will not be elaborated here. However, it should be noted that the switching frequency of non-high-frequency switches is relatively low. Therefore, when designing the circuit, appropriate values need to be selected according to the switching frequency range of non-high-frequency switches. The relatively low switching frequency may affect the response speed and efficiency of the circuit, so comprehensive consideration is required.

[0094] In some embodiments, the first switch 41 and the second switch 51 are any one of MOS transistors, IGBTs or relays.

[0095] In this way, selecting MOS transistors, IGBTs or relays for the first switch 41 and the second switch 51 can be respectively applicable to different usage scenarios, which is beneficial to broadening the usage range of the bidirectional DC power conversion circuit 100.

[0096] Specifically, the first switch 41 and the second switch 51 can be selected as any one or two of MOS transistors, IGBTs or relays.

[0097] It should be noted that MOS transistors have high input impedance and low on-resistance, so the power consumption is very low in the switched state. And MOS transistors have extremely high switching speed and can work in high-frequency environments. In addition, MOS transistors are controlled to conduct and turn off through the gate voltage, and the control signal is simple and easy to implement.

[0098] IGBT combines the advantages of MOSFET and bipolar transistors and can withstand high voltage and large current. And IGBT has high thermal stability and impact resistance and can maintain stable performance in harsh working environments. The on-resistance of IGBT is relatively low and the loss is small during the switching process, so it has high efficiency.

[0099] Relays achieve the on-off of the circuit through mechanical contacts and have the function of electrical isolation. In addition, relays can withstand large load currents and voltages and are applicable to various load types. The control signal of the relay is relatively simple and can control high-voltage and large-current loads through low-voltage and low-current signals.

[0100] Specifically, which high-frequency switch to select for the first switch 41 and the second switch 51 can be selected according to actual usage requirements.

[0101] Please refer to Figure 2 and Figure 3 , in some embodiments, the controller 80 is used to control the first switch 41 to disconnect and the second switch 51 to disconnect, so that the bidirectional DC power conversion circuit 100 operates in the asymmetric CLLC mode.

[0102] In this way, the bidirectional DC power conversion circuit 100 operates in the CLLC mode, enabling bidirectional power flow and facilitating high power conversion efficiency.

[0103] Specifically, in the embodiments of the present application, the controller 80 can be used to control the disconnection of the first switch 41 and the disconnection of the second switch 51 according to actual usage requirements and electrical parameters, so that the bidirectional DC power conversion circuit 100 enters the CLLC mode.

[0104] The CLLC mode is a typical topology of a bidirectional full-bridge LLC resonant converter, consisting of a forward LLC and a reverse LC topology. The CLLC mode has soft-switching characteristics, high energy efficiency, and can effectively reduce electromagnetic interference, improving the stability and reliability of the system.

[0105] Please refer to Figure 2 , in some embodiments, when the second resonant network 50 includes a first inductor 42 and a first capacitor 43 connected in series, and the controller 80 controls the disconnection of the first switch 41 and the disconnection of the second switch 51, the bidirectional DC power conversion circuit 100 will enter the CLLC mode. It should be noted that this mode is more suitable for scenarios that require high efficiency, high stability, wide voltage range, and good soft-switching characteristics.

[0106] Please refer to Figure 3 , in some embodiments, when the second resonant network 50 only includes a second capacitor 52, and the controller 80 controls the disconnection of the first switch 41 and the disconnection of the second switch 51, the bidirectional DC power conversion circuit 100 will enter the asymmetric CLLC mode. The asymmetric CLLC mode can achieve higher conversion efficiency under specific working conditions and can adapt to more complex working conditions and a wider range of application scenarios. It should be noted that the asymmetric CLLC mode is more suitable for scenarios with wide voltage range, high efficiency requirements, adaptation to complex working conditions, and volume and weight limitations.

[0107] In some embodiments, the controller 80 is used to control the disconnection of the first switch 41 and the conduction of the second switch 51, so that the bidirectional DC power conversion circuit 100 operates in the LLC mode.

[0108] In this way, the bidirectional DC power conversion circuit 100 operates in the LLC mode, which 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.

[0109] Specifically, in the embodiments of the present application, the controller 80 can be used to control the disconnection of the first switch 41 and the conduction of the second switch 51 according to actual usage requirements and electrical parameters, so that the bidirectional DC power conversion circuit 100 enters the LLC mode.

[0110] The LLC mode refers to the LLC topology, i.e., 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 the 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 bidirectional DC power conversion circuits 100 that require high efficiency, wide voltage range, high power density, good dynamic response ability, low electromagnetic interference, and high reliability.

[0111] In some embodiments, the controller 80 is used to control the first switch 41 to conduct and the second switch 51 to conduct, so that the bidirectional DC power conversion circuit 100 operates in the full-bridge circuit mode.

[0112] In this way, making the bidirectional DC power conversion circuit 100 operate in the full-bridge circuit mode facilitates handling larger currents and meeting the application scenarios of high-power output.

[0113] Specifically, in the embodiments of the present application, the first switch 41 can be controlled to conduct and the second switch 51 to conduct through the controller 80 according to actual usage requirements and electrical parameters, so that the bidirectional DC power conversion circuit 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 states 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 conducts and the low-side switch cuts 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 conducts and the high-side switch cuts 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 80 is used to control the first switch 41 to conduct and the second switch 51 to disconnect, so that the bidirectional DC power conversion circuit 100 operates in the phase-shift mode.

[0116] In this way, making the bidirectional DC power conversion circuit 100 operate in the phase-shift mode is beneficial to improving the conversion efficiency, reducing energy loss, and reducing the volume. It is suitable for application scenarios that require precise control and adjustment. In addition, the phase-shift mode has advantages when a wide range of output voltage regulation is required.

[0117] Specifically, in the embodiments of the present application, the first switch 41 can be controlled to be turned off and the second switch 51 can be controlled to be turned on according to actual usage requirements and electrical parameters, so that the bidirectional DC power conversion circuit 100 enters the phase-shifting mode.

[0118] The phase-shifting mode refers to an operating mode that achieves specific functions by adjusting the phase of a signal or voltage. Specifically, the phase-shifting mode can be achieved in various ways, including but not limited to adjusting the impedance of components in a circuit, using a phase-shifting circuit, or changing the phase of a signal through signal processing techniques. It should be noted that the phase-shifting mode is more suitable for complex application scenarios that require high performance, low loss, fast response, high power density, specific power factor regulation, and energy storage and grid connection.

[0119] Please refer to Figure 2 and Figure 3 , in some embodiments, the first DCDC circuit 60 includes a first full-bridge circuit 61 and a third capacitor 62 connected in parallel. Both ends of the first full-bridge circuit 61 are connected to the positive and negative electrodes of the first end 10. The other two ends of the first full-bridge circuit 61 are connected to the two electrodes of the primary side of the transformer 30. The third capacitor 62 is connected to the positive and negative electrodes of the first end 10;

[0120] The second DCDC circuit 70 includes a second full-bridge circuit 71 and a fourth capacitor 72 connected in parallel. Both ends of the second full-bridge circuit 71 are connected to the positive and negative electrodes of the second end 20. The other two ends of the second full-bridge circuit 71 are connected to the two electrodes of the secondary side of the transformer 30. The fourth capacitor 72 is connected to the positive and negative electrodes of the second end 20.

[0121] In this way, the first DCDC circuit 60 and the second DCDC circuit 70 are used to achieve the conversion of electrical energy, and at the same time, they can also balance the supply and demand relationship to a certain extent, improving the overall stability and reliability.

[0122] Specifically, in some embodiments, the DCDC circuit usually uses a bidirectional switch or a combination of two unidirectional switches to achieve bidirectional energy flow. By controlling the conduction and cutoff sequence and time of the switches, the transmission of electrical energy from the first end 10 to the second end 20 (such as boosting or bucking) and the reverse transmission from the second end 20 to the first end 10 can be achieved.

[0123] It should be noted that when using the first DCDC circuit and the second DCDC circuit, the required input and output voltage ranges need to be determined to ensure that the first DCDC circuit and the second DCDC circuit can meet the system requirements. At the same time, the voltage stability and ripple requirements also need to be considered.

[0124] In an embodiment of the present application, the first DCDC circuit includes a first full-bridge circuit 61 and a third capacitor 62 connected in parallel, and the second DCDC circuit includes a second full-bridge circuit 71 and a fourth capacitor 72 connected in parallel.

[0125] In this way, the full-bridge circuit is used to achieve bidirectional current flow according to the control signal, and can also improve the reliability of the bidirectional DC power conversion circuit 100; the capacitor is used to smooth the output voltage, filter, provide energy buffering, and improve the system dynamic response.

[0126] Specifically, the full-bridge circuit is a circuit structure composed of four switching tubes (usually MOSFETs or IGBTs), and these switching tubes are connected in a bridge manner, capable of realizing DC-DC or DC-AC conversion. In the DCDC circuit, the full-bridge circuit is mainly used to achieve voltage step-up / 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.

[0127] The first full-bridge circuit 61 and the second full-bridge circuit 71 can achieve the conversion from the input voltage to the output voltage by controlling the on / off of the switching tubes, including boosting, bucking, or keeping the voltage unchanged. In the bidirectional DC power conversion circuit 100, the full-bridge circuit allows current to flow bidirectionally between the input and the output, realizing bidirectional energy transmission. By optimizing the switching timing and duty cycle of the switching tubes, higher conversion efficiency can be achieved and energy loss can be reduced.

[0128] The third capacitor 62 and the fourth capacitor 72 are used to smooth the pulsation and noise of the output voltage, making the output voltage more stable. During the period when the switching tube is turned off, the capacitor can store energy and provide continuous current supply for the load. Using a capacitor at the first end 10 can filter out high-frequency noise and interference in the input voltage.

[0129] In some embodiments, the first end 10 is configured to be connected to the energy storage power system, and the first end 10 is used to receive electrical energy from the energy storage power system, or to deliver electrical energy to the energy storage power system;

[0130] The second end 20 is configured to be connected to the charging gun 200, and the second end 20 is used to receive electrical energy from the electric vehicle through the charging gun 200, or to deliver electrical energy to the electric vehicle through the charging gun 200.

[0131] In this way, the first end 10 can be used as the input end of the bidirectional DC power conversion circuit 100, and the second end 20 can be used as the output end of the bidirectional DC power conversion circuit 100.

[0132] Specifically, in the embodiments of the present application, the first end 10 serves as the input end, and the second end 20 serves as the output end. The electric energy of the energy storage power supply system flows from the first end 10 to the second end 20 for several days and is output from the charging gun 200. 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.

[0133] Please refer to Figure 1 , 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 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 mains electricity into direct current and storing it in the at least one battery pack.

[0134] In some embodiments, the bidirectional DC power conversion circuit 100 is configured such that when the energy storage power supply system charges an electric vehicle, the power direction of the bidirectional DC power conversion circuit 100 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 direction of the bidirectional DC power conversion circuit 100 is from the second end 20 to the first end 10.

[0135] 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.

[0136] Specifically, in the embodiments of the present application, the first end 10 serves as the input end, and the second end 20 serves as the output end. The power 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 direction of the bidirectional DC power conversion circuit 100 is from the second end 20 to the first end 10. In some embodiments, the energy storage power supply system is a home energy storage power supply system or a balcony photovoltaic energy storage system. Among them, the home 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 small and easy to carry and move, and its position can be transferred according to the user's electricity demand, such as from the balcony position to the garage or even outdoors, etc., its capacitance is relatively small, and the power provided is also relatively small.

[0137] In the description of this specification, the description referring 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 embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0138] 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, the 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, the meaning of "a plurality" is at least two, for example two, three, unless otherwise specifically and clearly defined.

[0139] 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 conversion circuit, characterized in that: include: First end; The second end; transformer; a first DCDC circuit and a first resonant network connected in sequence between the first end and the primary side of the transformer; A first switch connected in parallel with the first resonant network and between the first DCDC circuit and the primary side of the transformer; a second DCDC circuit and a second resonant network connected in sequence between the second end and the secondary side of the transformer; A second switch connected in parallel with the second resonant network and between the second DCDC circuit and the secondary side of the transformer; The controller is configured to control the on and off of the first switch and the second switch.

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

3. The bidirectional DC power conversion circuit according to claim 2, characterized in that: One end of the first switch is connected to one end of the first capacitor away from the first inductor, and the other end is connected to one end of the first inductor away from the first capacitor. Both ends of the second switch are respectively connected to both ends of the second capacitor.

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

5. The bidirectional DC power conversion circuit according to claim 4, characterized in that: One end of the first switch is connected to one end of the first capacitor away from the first inductor, and the other end is connected to one end of the first inductor away from the first capacitor; one end of the second switch is connected to one end of the second capacitor away from the second inductor, and the other end is connected to one end of the second inductor away from the second capacitor.

6. The bidirectional DC power conversion circuit according to claim 1, characterized in that: The first switch and the second switch are high-frequency switching switches.

7. The bidirectional DC power conversion circuit according to claim 6, characterized in that: The first switch and the second switch are any one of a MOS tube, an IGBT or a relay.

8. The bidirectional DC power conversion circuit according to claim 1, characterized in that: The controller is used to control the first switch to be disconnected and the second switch to be disconnected, so that the bidirectional DC power conversion circuit operates in an asymmetric CLLC mode.

9. The bidirectional DC power conversion circuit according to claim 1, characterized in that: The controller is used to control the first switch to be disconnected and the second switch to be turned on, so that the bidirectional DC power conversion circuit operates in LLC mode.

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

11. The bidirectional DC power conversion circuit according to claim 1, characterized in that: The controller is used to control the first switch to be turned on and the second switch to be turned off, so that the bidirectional DC power conversion circuit operates in a phase shift mode.

12. The bidirectional DC power conversion circuit according to claim 1, characterized in that: The first DCDC circuit includes a first full-bridge circuit and a third capacitor connected in parallel, two ends of the first full-bridge circuit are connected to the positive and negative electrodes of the first end, the other two ends of the first full-bridge circuit are connected to the two electrodes of the primary side of the transformer, and the third capacitor is connected to the positive and negative electrodes of the first end; The second DCDC circuit includes a second full-bridge circuit and a fourth capacitor connected in parallel, the two ends of the second full-bridge circuit are connected to the positive and negative electrodes of the second end, the other two ends of the second full-bridge circuit are connected to the two electrodes of the secondary side of the transformer, and the fourth capacitor is connected to the positive and negative electrodes of the second end.

13. The bidirectional DC power conversion circuit according to claim 1, characterized in that: The first end is configured to be connected to an energy storage power supply system, and the first end is used to receive electric energy from the energy storage power supply system, or to transmit electric energy to the energy storage power supply system; The second end is configured to be connected to a charging gun, and the second end is used to receive electric energy from the electric vehicle through the charging gun, or to transmit electric energy to the electric vehicle through the charging gun.

14. A DC charging pile, characterized in that: include: A charging gun, which is used to connect to an electric vehicle; The bidirectional DC power conversion circuit according to any one of claims 1 to 13, wherein the first end is connected to the energy storage power supply system, and the second end is connected to the charging gun.

15. The DC charging pile according to claim 14, characterized in that: The bidirectional DC power conversion circuit is configured so that when the energy storage power supply system charges the electric vehicle, the power of the bidirectional DC power 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 bidirectional DC power conversion circuit flows from the second end to the first end.

16. 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 conversion circuit as described in claims 1-13.

Images