Circuit, charging device, and control method for circuit

Abstract

A circuit, a charging device, and a control method for a circuit. The circuit comprises an energy storage unit and a switching sub-circuit, wherein the energy storage unit is electrically connected to the switching sub-circuit; the switching sub-circuit is electrically connected to at least one of a power factor correction circuit and a direct current–direct current circuit; and the switching sub-circuit is configured to: use electrical energy stored in the energy storage unit to pre-charge the power factor correction circuit or the direct current–direct current circuit; or, store, into the energy storage unit, electrical energy discharged from the power factor correction circuit or the direct current–direct current circuit.

Description

Circuits, charging devices, and circuit control methods

[0001] This application claims priority to Chinese patent application No. 202411550702.7, filed on October 31, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of charging equipment technology, and in particular to a circuit, a charging device, and a control method for the circuit. Background Technology

[0003] With the advancement of high-power charging technology for electric vehicles, supercharging equipment has been widely adopted in recent years. Superchargers have high charging power (generally above 600kW), and their power conversion is composed of multiple internal charging power components.

[0004] The charging power supply assembly consists of two stages. The first stage is a power factor correction (PFC) component, which has two functions: first, to correct the AC input power factor and reduce the electrical harmonics injected into the AC grid by the power supply assembly; and second, to convert the AC input to the supercharger into non-isolated DC (this DC is not electrically isolated from the AC grid and has large ripple, so it cannot directly charge the battery). The second stage is a direct current-to-direct current (DC-DC) converter, which further converts the non-isolated, high-ripple DC generated by the power factor correction component into isolated, low-ripple DC that can directly charge the battery. Summary of the Invention

[0005] This disclosure provides a circuit, a charging device, and a method for controlling the circuit.

[0006] In a first aspect, a circuit is provided, comprising: an energy storage unit and a switching sub-circuit; the energy storage unit is electrically connected to the switching sub-circuit; the switching sub-circuit is electrically connected to at least one of a power factor correction circuit and a DC-DC conversion circuit; the switching sub-circuit is configured to: pre-charge the power factor correction circuit or the DC-DC conversion circuit using electrical energy stored in the energy storage unit; or, store electrical energy discharged by the power factor correction circuit or the DC-DC conversion circuit in the energy storage unit.

[0007] Based on the above solutions, some embodiments of this disclosure provide a circuit that pre-charges the power factor correction circuit and the DC-DC conversion circuit through an energy storage unit and a switching sub-circuit. This eliminates the need for a pre-charging resistor, further reducing costs and avoiding electromagnetic compatibility issues, thus improving energy efficiency. Simultaneously, some embodiments of this disclosure actively discharge excess energy from the power factor correction circuit and the DC-DC conversion circuit to the energy storage unit for recycling. This achieves both energy discharge from the power factor correction circuit and the DC-DC conversion circuit and energy savings.

[0008] In some embodiments, the switching sub-circuit includes: a buck-boost module; the buck-boost module is electrically connected to the energy storage unit, and is also electrically connected to at least one of the power factor correction circuit and the DC-DC conversion circuit; the buck-boost module is configured to: transform the voltage provided by the energy storage unit to output a target pre-charge voltage to the power factor correction circuit or the DC-DC conversion circuit; or, transform the voltage discharged by the power factor correction circuit or the DC-DC conversion circuit to output a target discharge voltage to the energy storage unit.

[0009] In some embodiments, the buck-boost module includes: a first switching unit, a second switching unit, and an energy storage unit; a first terminal of the first switching unit is electrically connected to a first terminal of the buck-boost module, a second terminal of the first switching unit is electrically connected to a second terminal of the buck-boost module, and is also electrically connected to a second terminal of the energy storage unit and a first terminal of the second switching unit; a third terminal of the first switching unit is electrically connected to a third terminal of the buck-boost module, and is also electrically connected to a first terminal of the energy storage unit; and a second terminal of the second switching unit is electrically connected to a fourth terminal of the buck-boost module.

[0010] When the first switching unit is turned on and the second switching unit is turned off, the energy storage unit is configured to charge the energy storage unit; after the energy storage unit is charged, the first switching unit is turned off and the second switching unit is turned on, and the energy storage unit is configured to precharge the power factor correction circuit or the DC-DC conversion circuit.

[0011] When the first switch unit is off and the second switch unit is on, the power factor correction circuit or DC-DC conversion circuit discharges electrical energy to charge the energy storage unit; after the energy storage unit is charged, the first switch unit is on and the second switch unit is off, and the energy storage unit is configured to charge the energy storage section.

[0012] In some embodiments, the first switching unit includes: a first capacitor and a first switching transistor; a first terminal of the first capacitor is electrically connected to a first terminal of the first switching unit, and the first terminal of the first capacitor is also electrically connected to a first terminal of the first switching transistor; a second terminal of the first capacitor is electrically connected to a second terminal of the first switching unit; and a second terminal of the first switching transistor is electrically connected to a third terminal of the first switching unit.

[0013] In some embodiments, the second switching unit includes a second switching transistor; a first terminal of the second switching transistor is electrically connected to a first terminal of the second switching unit, and a second terminal of the second switching transistor is electrically connected to a second terminal of the second switching unit. The energy storage unit includes a first inductor; a first terminal of the first inductor is electrically connected to a first terminal of the energy storage unit, and a second terminal of the first inductor is electrically connected to a second terminal of the energy storage unit.

[0014] In some embodiments, the switching sub-circuit further includes: a switching module; the switching module is electrically connected to a buck-boost module; the switching module is electrically connected to at least one of a power factor correction circuit and a DC-DC conversion circuit; the switching module is configured to: electrically connect the buck-boost module to the power factor correction circuit to precharge or discharge the power factor correction circuit; or, electrically connect the buck-boost module to the DC-DC conversion circuit to precharge or discharge the DC-DC conversion circuit.

[0015] In some embodiments, the switching module includes: a first switching device and a second switching device; a first terminal of the first switching device is electrically connected to a second terminal of the switching module, a second terminal of the first switching device is electrically connected to a third terminal of the switching module, and a third terminal of the first switching device is electrically connected to a fifth terminal of the switching module; a first terminal of the second switching device is electrically connected to a first terminal of the switching module, a second terminal of the second switching device is electrically connected to a fourth terminal of the switching module, and a third terminal of the second switching device is electrically connected to a sixth terminal of the switching module.

[0016] In some embodiments, the third terminal of the switching module is electrically connected to the first terminal of the power factor correction circuit, the fourth terminal of the switching module is electrically connected to the second terminal of the power factor correction circuit, the fifth terminal of the switching module is electrically connected to the first terminal of the DC-DC conversion circuit, and the sixth terminal of the switching module is electrically connected to the second terminal of the DC-DC conversion circuit (120).

[0017] In some embodiments, the circuit further includes: a control sub-circuit electrically connected to the first switching device and the second switching device; the control sub-circuit is configured to: control the first terminal of the first switching device to be connected to the second terminal, and control the first terminal of the second switching device to be connected to the second terminal, so as to precharge or discharge the power factor correction circuit; or, control the first terminal of the first switching device to be connected to the third terminal, and control the first terminal of the second switching device to be connected to the third terminal, so as to precharge or discharge the DC-DC conversion circuit.

[0018] In some embodiments, the buck-boost module further includes: a second capacitor; a first terminal of the second capacitor is electrically connected to a first terminal of the energy storage unit, and a second terminal of the second capacitor is electrically connected to a second terminal of the second switching unit.

[0019] In some embodiments, the energy storage unit includes photovoltaic cells.

[0020] In a second aspect, a charging device is provided, comprising: a circuit, a power factor correction circuit, and a DC-DC conversion circuit, wherein a first terminal of the power factor correction circuit is electrically connected to a first terminal of the circuit, and a second terminal of the power factor correction circuit is electrically connected to a second terminal of the circuit; a first terminal of the DC-DC conversion circuit is electrically connected to a third terminal of the circuit, and a second terminal of the DC-DC conversion circuit is electrically connected to a fourth terminal of the circuit.

[0021] The beneficial effects of the second aspect and its possible embodiments can be referred to the first aspect, and will not be repeated here.

[0022] In some embodiments, the power factor correction circuit includes: a third capacitor; a first terminal of the third capacitor is electrically connected to a first terminal of the power factor correction circuit, and a second terminal of the third capacitor is electrically connected to a second terminal of the power factor correction circuit; the DC-DC conversion circuit includes: a fourth capacitor; a first terminal of the fourth capacitor is electrically connected to a first terminal of the DC-DC conversion circuit, and a second terminal of the fourth capacitor is electrically connected to a second terminal of the DC-DC conversion circuit.

[0023] Thirdly, a control method is provided for the circuit described above.

[0024] The switching sub-circuit is controlled to conduct in either the forward or reverse direction with the power factor correction circuit to precharge or discharge the power factor correction circuit; or, the switching sub-circuit is controlled to conduct in either the forward or reverse direction with the DC-DC conversion circuit to precharge or discharge the DC-DC conversion circuit.

[0025] The beneficial effects of the third aspect and its possible embodiments can be referred to the first aspect, and will not be repeated here.

[0026] In some embodiments, the switching sub-circuit includes a first switching device and a second switching device.

[0027] Controlling the switching sub-circuit and the power factor correction circuit to conduct in the forward or reverse direction includes: controlling the first terminal and the second terminal of the first switching device to conduct, and controlling the first terminal and the second terminal of the second switching device to conduct, so as to precharge or discharge the power factor correction circuit.

[0028] Controlling the switching sub-circuit and the DC-DC conversion circuit to conduct in the forward or reverse direction includes: controlling the first and third terminals of the first switching device to conduct, and controlling the first and third terminals of the second switching device to conduct, so as to precharge or discharge the DC-DC conversion circuit.

[0029] In some embodiments, the switching sub-circuit includes: a first capacitor, a first switching transistor, a second switching transistor, and a first inductor.

[0030] The control switch sub-circuit and the power factor correction circuit or DC-DC conversion circuit are forward-biased, including: in the first stage, controlling the first switch to be turned on and the second switch to be turned off; the energy storage unit charges the first inductor through the first capacitor; in the second stage, controlling the first switch to be turned off and the second switch to be turned on; the first inductor pre-charges the power factor correction circuit or DC-DC conversion circuit.

[0031] In some embodiments, during the forward conduction of the control switch sub-circuit and the power factor correction circuit or the DC-DC conversion circuit, the first switch is controlled to operate at a first set switching frequency and a first duty cycle.

[0032] In some embodiments, before the control switch sub-circuit is forward-biased with the power factor correction circuit or the DC-DC conversion circuit, the method further includes: receiving pre-charge information, the pre-charge information including a target pre-charge voltage and a pre-charge time; and determining a first set switching frequency and a first duty cycle based on the pre-charge information.

[0033] In some embodiments, the switching sub-circuit includes: a first capacitor, a first switching transistor, a second switching transistor, and a first inductor.

[0034] The control switch sub-circuit is reverse-biased to the power factor correction circuit or DC-DC converter circuit, including: in the first stage, controlling the first switch to be turned off and the second switch to be turned on; the power factor correction circuit or DC-DC converter circuit charges the first inductor.

[0035] In the second stage, the first switch is turned on and the second switch is turned off; the first inductor charges the energy storage unit through the first capacitor.

[0036] In some embodiments, during the reverse conduction of the control switch sub-circuit with the power factor correction circuit or the DC-DC conversion circuit, the second switch is controlled to operate at a second set switching frequency and a second duty cycle.

[0037] In some embodiments, before the control switch sub-circuit is reverse-biased to the power factor correction circuit or the DC-DC conversion circuit, the method further includes: receiving power discharge information, the power discharge information including a target discharge voltage and a discharge time; and determining a second set switching frequency and a second duty cycle based on the power discharge information.

[0038] In some embodiments, before the control switch subcircuit and the power factor correction circuit are forward-biased, the method further includes: receiving a first pre-charge instruction, the first pre-charge instruction being used to instruct the circuit to pre-charge the power factor correction circuit.

[0039] Before the control switch sub-circuit and the power factor correction circuit are reverse-biased, the method further includes: receiving a first discharge command, which instructs the circuit to discharge power to the power factor correction circuit.

[0040] Before the control switch sub-circuit and the DC-DC conversion circuit are forward-biased, the method further includes: receiving a second pre-charge command, the second pre-charge command being used to instruct the circuit to pre-charge the DC-DC conversion circuit.

[0041] Before the control switch sub-circuit is reverse-biased to the DC-DC conversion circuit, the method further includes: receiving a second discharge command, which instructs the circuit to discharge electrical energy to the DC-DC conversion circuit. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of some embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 is a schematic diagram of a charging device in the related art;

[0044] Figure 2 is a schematic diagram of a PFC component in the related technology;

[0045] Figure 3 is a schematic diagram of another PFC component in the related technology;

[0046] Figure 4 is a schematic diagram of a DC component in the related technology;

[0047] Figure 5 is a schematic diagram of a circuit according to some embodiments;

[0048] Figure 6 is a schematic diagram of another circuit according to some embodiments;

[0049] Figure 7 is a schematic diagram of yet another circuit according to some embodiments;

[0050] Figure 8 is a flowchart of a power factor correction circuit pre-charging process according to some embodiments;

[0051] Figure 9 is a flowchart of a DC-DC converter circuit pre-charging according to some embodiments;

[0052] Figure 10 is a flowchart of power factor correction circuit energy discharge according to some embodiments;

[0053] Figure 11 is a flowchart of power discharge in a DC-DC conversion circuit according to some embodiments;

[0054] Figure 12 is a schematic diagram of a charging device according to some embodiments. Detailed Implementation

[0055] The technical solutions of some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0056] In the description of this disclosure, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or relative positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure. Unless otherwise specified, the above-mentioned orientational descriptions can be flexibly set in practical applications, provided that the relative positional relationships shown in the accompanying drawings are satisfied.

[0057] 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 number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0058] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "communication" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the meaning of the above terms in this disclosure based on the actual situation.

[0059] In some embodiments of this disclosure, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes that element.

[0060] In some embodiments of this disclosure, the words "exemplarily" or "for example" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design described as "exemplarily" or "for example" in some embodiments of this disclosure should not be construed as being more preferred or advantageous than other embodiments or designs. Rather, the use of words such as "exemplarily" or "for example" is intended to present the relevant concepts by way of example.

[0061] With the advancement of high-power charging technology for electric vehicles, supercharging equipment has been widely adopted in recent years. Superchargers have high charging power (generally above 600kW), and their power conversion is composed of multiple internal charging power components (see Figure 1).

[0062] The charging power supply assembly consists of two stages. The first stage is a power factor correction (PFC) component, which has two functions: first, to correct the AC input power factor and reduce the electrical harmonics injected into the AC grid by the power supply assembly; and second, to convert the AC input to the supercharger into non-isolated DC (this DC is not electrically isolated from the AC grid and has large ripple, so it cannot directly charge the battery). The second stage is a direct current-to-direct current (DC-DC) converter, which further converts the non-isolated, high-ripple DC generated by the power factor correction component into isolated, low-ripple DC that can directly charge the battery.

[0063] However, in related technologies, the PFC module of the supercharger stack requires an external pre-charge module to achieve PFC pre-charging. This pre-charge module needs to draw power separately from the AC live / neutral wire (L / N), which introduces additional AC conducted electromagnetic compatibility issues to the entire supercharger system. For the DC-DC module, pre-charging requires the PFC module. Since the PFC module's switching transistors are high-power transistors and numerous, the pre-charging of the supercharger stack's DC-DC module wastes a significant amount of energy, further reducing system energy efficiency. Furthermore, after charging is complete, both the PFC module and the DC-DC module need to discharge energy, which is released through resistors, resulting in substantial energy waste.

[0064] For ease of explanation, the DC-DC component will be referred to as the DC component in the following text.

[0065] For example, due to their high power, supercharging units typically have their PFC and DC components designed separately, as independent PFC and DC components. A supercharging stack uses multiple PFC components connected in parallel to form a PFC stage, and multiple DC components connected in parallel to form a DC stage. The output of the PFC stage serves as the input of the DC stage; the output of the DC stage can directly charge the power battery. The PFC stage output voltage is called the BUS voltage or PFC-BUS, and the DC output voltage is called high-voltage direct current (HVDC).

[0066] Referring to Figure 2, the PFC component is connected to the AC power supply via a relay. The PFC component typically has a large-capacity capacitor on its output side. If these capacitors are not pre-charged when the AC power is applied, a momentary short circuit will occur when the AC relay closes, generating a large inrush current. In severe cases, this can damage components in the circuit, such as metal-oxide-semiconductor field-effect transistors (MOSFETs). Traditional PFC circuits use a resistor connected in parallel across the contacts of each AC input relay to eliminate the startup inrush current; this resistor is called the pre-charge resistor. After pre-charging the large-capacity capacitors, the AC input relay closes. Traditional PFC components use this pre-charge resistor to pre-charge the PFC-BUS voltage.

[0067] Supercharger systems have high power outputs and large output capacitors in the PFC components. When the supercharger is powered on by AC but not charging the vehicle or battery (this state is called standby), the AC power is electrically connected to the PFC circuit due to the relay being closed. This creates a large circulating current inside, resulting in significant standby losses for the PFC components. To reduce standby losses in the supercharger, it is necessary to disconnect the AC relay and the pre-charge resistor during standby, completely cutting off the pre-charge circuit to reduce standby losses.

[0068] Referring to Figure 3, the PFC circuit must have a pre-charge function. When the pre-charge resistor is removed, a new PFC pre-charge circuit needs to be designed. In related technologies, an external controlled low-power power supply (typically several hundred watts) is used outside the PFC component of the supercharger to achieve pre-charging of the PFC component. The external PFC pre-charge component (hereinafter referred to as the pre-charge component) receives a single-phase AC L / N input. After the PFC issues a power-on command, the output voltage of the pre-charge component rises to the uncontrolled rectified voltage VBUS_0 of the supercharger PFC component. Subsequently, the supercharger PFC component closes the AC input relay, achieving zero-voltage closure of the AC input relay.

[0069] Referring to Figures 2 to 4, the large-capacity capacitor on the output side of the PFC component of the supercharger stack is generally discharged by a dummy load on the PFC output side (a resistor connected in parallel across the large-capacity capacitor). During normal charging, this resistor is used to enhance the stability of circuit control. After charging stops, it discharges the residual voltage of the large-capacity capacitor. This is called a passive discharge resistor.

[0070] Referring to Figure 4, the DC component of the supercharger stack is required by charging standards to have an active discharge function. That is, after the supercharger system stops charging, the DC component needs to discharge the residual high voltage at its output terminal to a specified voltage value within a predetermined time to ensure electrical safety. In related technologies, a switching transistor and a discharge resistor are connected in parallel at the output capacitor of each DC component. When the system is charging, the switching transistor is open, and the discharge resistor is disconnected from the HVDC circuit, resulting in no losses. When the system stops charging and enters the active discharge process, the switching transistor is closed, and the discharge resistor is connected in parallel to the DC component's output capacitor to dissipate the energy of the output capacitor, discharging the residual voltage to a predetermined safe voltage value.

[0071] Based on this, some embodiments of this disclosure provide a circuit. For example, as shown in FIG5, circuit 100 includes: an energy storage unit 1 and a switching sub-circuit 2.

[0072] The energy storage unit 1 is electrically connected to the switch circuit 2.

[0073] The switching sub-circuit 2 is electrically connected to at least one of the power factor correction circuit 110 and the DC-DC conversion circuit 120.

[0074] The switch sub-circuit 2 is configured to: precharge the power factor correction circuit 110 or the DC-DC conversion circuit 120 using the electrical energy stored in the energy storage unit 1; or store the electrical energy discharged by the power factor correction circuit 110 or the DC-DC conversion circuit 120 into the energy storage unit 1.

[0075] In some embodiments, the energy storage unit 1 includes a photovoltaic cell.

[0076] Here, the switch sub-circuit 2 can be electrically connected only to the power factor correction circuit 110, or only to the DC-DC conversion circuit 120, or both the power factor correction circuit 110 and the DC-DC conversion circuit 120.

[0077] In other words, the energy is first stored in the energy storage unit 1, and then the stored energy is transmitted to the switch sub-circuit 2. The switch sub-circuit 2 then transmits the energy to the power factor correction circuit 110 or the DC-DC conversion circuit 120 to precharge the power factor correction circuit 110 or the DC-DC conversion circuit 120.

[0078] Furthermore, after the power factor correction circuit 110 completes charging or operation, it will actively discharge the energy. At this time, the power factor correction circuit 110 stores the discharged electrical energy in the energy storage unit 1 for use during the next pre-charge. Similarly, after the DC-DC conversion circuit 120 completes charging or operation, it will actively discharge the energy. At this time, the DC-DC conversion circuit 120 stores the discharged electrical energy in the energy storage unit 1 for use during the next pre-charge.

[0079] It should be noted that pre-charging refers to the process by which the circuit pre-charges the power supply output (PFC output or DC output) to achieve a faster output voltage slow start and reduce input inrush current.

[0080] Based on the above solutions, some embodiments of this disclosure provide a circuit that pre-charges the power factor correction circuit and the DC-DC conversion circuit through an energy storage unit and a switching sub-circuit. This eliminates the need for a pre-charging resistor, further reducing costs and avoiding electromagnetic compatibility issues, thus improving energy efficiency. Furthermore, some embodiments of this disclosure actively discharge excess power from the power factor correction circuit and the DC-DC conversion circuit to the energy storage unit for recycling. This achieves both energy discharge from the power factor correction circuit and the DC-DC conversion circuit and energy savings.

[0081] As shown in Figure 6, the switching sub-circuit 2 includes a step-up / step-down module 21 and a switching module 22.

[0082] The buck-boost module 21 is electrically connected to the energy storage unit 1, and the buck-boost module 21 is also electrically connected to the switching module 22.

[0083] The switching module 22 is electrically connected to at least one of the power factor correction circuit 110 and the DC-DC conversion circuit 120.

[0084] In other words, the switching module 22 can be electrically connected only to the power factor correction circuit 110, or only to the DC-DC conversion circuit 120, or both the power factor correction circuit 110 and the DC-DC conversion circuit 120.

[0085] The step-up / step-down module 21 is configured to: transform the voltage provided by the energy storage unit 1 to output a target pre-charge voltage to the power factor correction circuit 110 or the DC-DC conversion circuit 120; or transform the voltage discharged by the power factor correction circuit 110 or the DC-DC conversion circuit 120 to output a target discharge voltage to the energy storage unit 1.

[0086] The switching module 22 is configured to: electrically connect the buck-boost module 21 to the power factor correction circuit 110 to precharge or discharge the power factor correction circuit 110; or electrically connect the buck-boost module 21 to the DC-DC converter circuit 120 to precharge or discharge the DC-DC converter circuit 120.

[0087] In other words, energy is first stored in the energy storage unit 1, and then the stored energy is transmitted to the buck-boost module 21. When the switching module 22 connects the buck-boost module 21 to the power factor correction circuit 110, the buck-boost module 21 converts the voltage provided by the energy storage unit 1 and then transmits the energy to the power factor correction circuit 110 to precharge the power factor correction circuit 110. When the switching module 22 connects the buck-boost module 21 to the DC-DC converter circuit 120, the buck-boost module 21 converts the voltage provided by the energy storage unit 1 and then transmits the energy to the DC-DC converter circuit 120 to precharge the DC-DC converter circuit 120.

[0088] In addition, after the power factor correction circuit 110 has finished charging or working, it will actively discharge. At this time, the switching module 22 connects the buck-boost module 21 to the power factor correction circuit 110. The power factor correction circuit 110 stores the discharged electrical energy in the energy storage unit 1 through the buck-boost module 21 for use during the next pre-charge.

[0089] Similarly, after the DC-DC converter 120 has finished charging or working, it will actively discharge. At this time, the switching module 22 connects the step-up / step-down module 21 to the DC-DC converter 120. The DC-DC converter 120 stores the discharged electrical energy in the energy storage unit 1 through the step-up / step-down module 21 for use during the next pre-charging.

[0090] As shown in Figure 7, the step-up / step-down module 21 includes: a first switching unit 23, a second switching unit 24, and an energy storage unit 25.

[0091] The first end 231 of the first switching unit 23 is electrically connected to the first end 211 of the buck-boost module 21. The second end 232 of the first switching unit 23 is electrically connected to the second end 212 of the buck-boost module 21, and is also electrically connected to the second end 252 of the energy storage unit 25 and the first end 241 of the second switching unit 24. The third end 233 of the first switching unit 23 is electrically connected to the third end 213 of the buck-boost module 21, and is also electrically connected to the first end 251 of the energy storage unit 25. The fourth end 214 of the buck-boost module 21 is electrically connected to the second end 242 of the second switching unit 24.

[0092] When the first switch unit 23 is turned on and the second switch unit 24 is turned off, the energy storage unit 1 is configured to charge the energy storage unit 25; after the energy storage unit is charged, the first switch unit 23 is turned off and the second switch unit is turned on, and the energy storage unit 25 is configured to precharge the power factor correction circuit 110 or the DC-DC conversion circuit 120.

[0093] When the first switch unit 23 is turned off and the second switch unit 24 is turned on, the power factor correction circuit 110 or the DC-DC conversion circuit 120 discharges electrical energy to charge the energy storage unit 25; after the energy storage unit 25 is charged, the first switch unit 23 is turned on and the second switch unit is turned off, and the energy storage unit 25 is configured to charge the energy storage section 1.

[0094] In other words, when the energy storage unit 1 is pre-charging the power factor correction circuit 110 or the DC-DC conversion circuit 120, the first switching unit 23 is first turned on to charge the energy storage unit 25. After the energy storage unit 25 has finished charging, the first switching unit 23 is turned off, and then the second switching unit 24 is turned on. The switching module 22 connects the buck-boost module 21 to the power factor correction circuit 110, and the energy storage unit 25 pre-charges the power factor correction circuit 110. The switching module 22 also connects the buck-boost module 21 to the DC-DC conversion circuit 120, and the energy storage unit 25 pre-charges the DC-DC conversion circuit 120.

[0095] When the power factor correction circuit 110 or the DC-DC conversion circuit 120 discharges power, the second switching unit 24 is first turned on to charge the energy storage unit 25. After the energy storage unit 25 has finished charging, the second switching unit 24 is turned off and the first switching unit 23 is turned on; the energy storage unit 25 charges the energy storage section.

[0096] As shown in Figure 7, the first switching unit 23 includes a first capacitor C1 and a first switching transistor Q1.

[0097] The first end of the first capacitor C1 is electrically connected to the first end 231 of the first switching unit 23 and also electrically connected to the first end of the first switching transistor Q1. The second end of the first capacitor C1 is electrically connected to the second end 232 of the first switching unit 23. The second end of the first switching transistor Q1 is electrically connected to the third end 233 of the first switching unit 23.

[0098] In some embodiments, the first switching transistor Q1 is a MOSFET.

[0099] The energy storage unit 1 can first store electrical energy in the first capacitor C1, and after the first switch is turned on, the first capacitor C1 stores electrical energy in the energy storage unit 25.

[0100] The second switching unit 24 includes: a second switching transistor Q2.

[0101] The first end of the second switch transistor Q2 is electrically connected to the first end 241 of the second switch unit 24, and the second end of the second switch transistor Q2 is electrically connected to the second end 242 of the second switch unit 24.

[0102] Energy storage unit 25 includes: a first inductor L1.

[0103] The first end of the first inductor L1 is electrically connected to the first end 251 of the energy storage unit 25, and the second end of the first inductor L1 is electrically connected to the second end 252 of the energy storage unit 25.

[0104] Referring to Figure 7, the switching module 22 includes: a first switching device SW1 and a second switching device SW2.

[0105] The first terminal S11 of the first switching device SW1 is electrically connected to the second terminal 222 of the switching module 22, the second terminal S12 of the first switching device SW1 is electrically connected to the third terminal 223 of the switching module 22, and the third terminal S13 of the first switching device SW1 is electrically connected to the fifth terminal 225 of the switching module 22.

[0106] The first terminal S21 of the second switching device SW2 is electrically connected to the first terminal 221 of the switching module 22, the second terminal S22 of the second switching device SW2 is electrically connected to the fourth terminal 224 of the switching module 22, and the third terminal S23 of the second switching device SW2 is electrically connected to the sixth terminal 226 of the switching module 22.

[0107] Circuit 100 (such as precharge and discharge sub-circuits) also includes: control sub-circuit 3.

[0108] The control sub-circuit 3 is electrically connected to the first switching device SW1 and the second switching device SW2.

[0109] The control sub-circuit 3 is configured to: control the first terminal S11 and the second terminal S12 of the first switching device SW1 to be turned on, and control the first terminal S21 and the second terminal S22 of the second switching device SW2 to be turned on, so as to precharge or discharge the power factor correction circuit 110; or, control the first terminal S11 and the third terminal S13 of the first switching device SW1 to be turned on, and control the first terminal S21 and the third terminal S23 of the second switching device SW2 to be turned on, so as to precharge or discharge the DC-DC conversion circuit 120.

[0110] For example, when the energy storage unit 1 is pre-charging the power factor correction circuit 110 or the DC-DC conversion circuit 120, the energy storage unit 1 first charges the first capacitor C1, then turns on the first switching unit 23, and charges the energy storage unit 25 through the first capacitor C1. After the energy storage unit 25 has finished charging, the first switching unit 23 is turned off, and then the second switching unit 24 is turned on. The control sub-circuit 3 controls the first terminal S11 and the second terminal S12 of the first switching device SW1 to be connected, and controls the first terminal S21 and the second terminal S22 of the second switching device SW2 to be connected, so that the energy storage unit 25 is pre-charging the power factor correction circuit 110. The control sub-circuit 3 controls the first terminal S11 and the third terminal S13 of the first switching device SW1 to be connected, and controls the first terminal S21 and the third terminal S23 of the second switching device SW2 to be connected, so that the energy storage unit 25 is pre-charging the DC-DC conversion circuit 120.

[0111] When the power factor correction circuit 110 or the DC-DC conversion circuit 120 discharges electrical energy, the second switching unit 24 is first turned on to charge the energy storage unit 25. After the energy storage unit 25 has finished charging, the second switching unit 24 is turned off, and then the first switching unit 23 is turned on. The energy storage unit 25 charges the energy storage section 1, thereby completing the discharge and storage of electrical energy.

[0112] That is, the third terminal 223 of the switching module 22 is electrically connected to the first terminal A1 of the power factor correction circuit 110, the fourth terminal 224 of the switching module 22 is electrically connected to the second terminal A2 of the power factor correction circuit 110, the fifth terminal 225 of the switching module 22 is electrically connected to the first terminal B1 of the DC-DC conversion circuit 120, and the sixth terminal 226 of the switching module 22 is electrically connected to the second terminal B2 of the DC-DC conversion circuit 120.

[0113] In some embodiments, the control sub-circuit 3 is also electrically connected to the control terminal of the first switch Q1 and the control terminal of the second switch Q2.

[0114] Here, the control terminal refers to the gate of the MOSFET.

[0115] The control sub-circuit 3 is also configured to control the on and off states of the first switch Q1 and the second switch Q2.

[0116] For example, when the buck-boost module is working in the forward direction, the first switch Q1 and the second switch Q2 work at a fixed switching frequency f with a period of T. The conduction time of the first switch Q1 is D1×T, where D1 is the duty cycle and T can be obtained by the following formula (1).

[0117] When the first switch Q1 is turned on, the first inductor L1 stores energy under the excitation of the first voltage V1. The inductance voltage of the first inductor L1 is positive at the top and negative at the bottom, and the change in the inductance current of the first inductor L1 satisfies formula (2).

[0118] Wherein, the first voltage V1 refers to the voltage across the first capacitor C1; ΔI_1 is the change in inductor current of the first inductor L1 when the first switch Q1 is turned on; L1 refers to the inductance value of the first inductor.

[0119] When the first switch Q1 is turned off and the second switch Q2 is turned on, the first inductor L1 releases energy. The voltage across the first inductor L1 is V2. The inductance voltage of the first inductor L1 is positive at the bottom and negative at the top. The time for the first inductor to release energy is T×(1-D1). The change in the current of the first inductor satisfies formula (3).

[0120] Where L1 refers to the inductance value of the first inductor; ΔI_2 is the change in the inductance current of the first inductor L1 when the first switch Q1 is off and the second switch Q2 is on.

[0121] After reaching steady state, the circuit satisfies formula (4). ΔI_1=ΔI_2 (4)

[0122] By combining formulas (2), (3) and (4), we can solve for formula (5) of the output voltage V2 of the buck-boost module relative to V1 when it is working in the forward direction.

[0123] As can be seen from formula (5), when D1 > 0.5, V2 > V1, and the circuit achieves voltage boost; when D1 < 0.5, V2 < V1, and the circuit achieves voltage reduction; when D = 0.5, V2 = V1.

[0124] Similarly, when the buck-boost module 21 operates in reverse, the first switch Q1 and the second switch Q2 operate at a fixed switching frequency f with a period of T. The conduction time of the second switch Q2 is D2×T, where D2 is the duty cycle of the second switch Q2.

[0125] When the second switch Q2 is turned on, the first inductor L1 stores energy under the excitation of the second voltage V2, and the change in inductor current satisfies formula (6).

[0126] Wherein, ΔI_3 is the change in inductor current of the first inductor L1 when the second switch Q2 is turned on.

[0127] When the second switch Q2 is turned off and the first switch Q1 is turned on, the first inductor L1 releases energy. The voltage across the first inductor L1 is V1, and the energy release time is T×(1-D2). The change in the current of the first inductor satisfies formula (7).

[0128] Where L1 refers to the inductance value of the first inductor; ΔI_4 is the change in the inductance current of the first inductor L1 when the second switch Q2 is off and the first switch Q1 is on.

[0129] After reaching steady state, the circuit satisfies formula (8). ΔI_3=ΔI_4 (8)

[0130] By combining formulas (6), (7) and (8), we can solve for formula (9) of the first voltage (output voltage) V1 of the buck-boost module relative to the second voltage V2 when working in reverse.

[0131] As can be seen from formula (9), when D2 > 0.5, V1 > V2, and the circuit achieves voltage boost; when D2 < 0.5, V1 < V2, and the circuit achieves voltage reduction; when D = 0.5, V1 = V2.

[0132] The above describes the forward and reverse operation of the buck-boost module. Forward operation means that the energy storage unit 1 pre-charges the power factor correction circuit 110 and the DC-DC conversion circuit 120 through the buck-boost module 21; reverse operation means that the power factor correction circuit 110 and the DC-DC conversion circuit 120 charge the energy storage unit 1 through the buck-boost module 21.

[0133] In other words, the buck-boost module is a dual-terminal switching power supply circuit, with one terminal voltage V1 and the other terminal voltage V2. It operates in two modes:

[0134] In forward operation, the input voltage is V1 (the first voltage mentioned above), and the output voltage is V2 (the second voltage mentioned above). The circuit gain is calculated using formula (10).

[0135] Wherein, K1 is the circuit gain of the buck-boost module when it is operating in the forward direction.

[0136] The target output voltage of the buck-boost module is V2. At this time, the buck-boost module needs to meet the requirement that, through control methods (including but not limited to variable duty cycle, variable frequency, etc.), the circuit gain K1 can be less than or equal to 1 or greater than 1, that is, it can output both boost and buck voltage.

[0137] When operating in reverse, the input voltage is V2 and the output voltage is V1. The circuit gain is calculated using formula (11).

[0138] Wherein, K2 is the circuit gain of the buck-boost module when it is working in reverse.

[0139] The target output voltage of the buck-boost module is V1. At this time, the buck-boost module needs to meet the requirement that, through control methods (including but not limited to variable duty cycle, variable frequency, etc.), the circuit gain K2 can be less than or equal to 1 or greater than 1, that is, it can output both boost and buck voltage.

[0140] In some embodiments, the buck-boost module 21 further includes a second capacitor C2.

[0141] The first end of the second capacitor C2 is electrically connected to the first end of the energy storage unit 25, and the second end of the second capacitor C2 is electrically connected to the second end of the second switching unit 24.

[0142] Here, the second capacitor C2 acts as a filter.

[0143] Figure 8 is a flowchart of the pre-charging process of a power factor correction circuit according to some embodiments. As shown in Figure 8, some embodiments of this disclosure provide a control method for a circuit, which includes steps S101 to S107.

[0144] S101, the control sub-circuit receives the first pre-charge command and pre-charge information.

[0145] The first pre-charge command instructs the circuit to pre-charge the power factor correction circuit. Pre-charge information includes the target pre-charge voltage and pre-charge time.

[0146] S102, the control switch sub-circuit and the power factor correction circuit are forward-biased.

[0147] S103, The control sub-circuit controls the first terminal of the first switching device to be connected to the second terminal, and controls the first terminal of the second switching device to be connected to the second terminal.

[0148] S104: Control the first switch to be turned on and the second switch to be turned off.

[0149] Here, the first switch operates at a first set switching frequency and a first duty cycle. The first set switching frequency and the first duty cycle are determined based on the pre-charge information. The determination method can be found in formulas (2) to (5).

[0150] S105, the energy storage unit charges the first inductor through the first capacitor.

[0151] S106: Control the first switch to be turned off and the second switch to be turned on.

[0152] S107, the first inductor precharges the power factor correction circuit.

[0153] Figure 9 is a flowchart of the pre-charging of a DC-DC converter circuit according to some embodiments. Referring to Figure 9, the control method further includes steps S201 to S207.

[0154] S201, the control sub-circuit receives the second pre-charge command and pre-charge information.

[0155] The second precharge command instructs the circuit to precharge the DC-DC converter. Precharge information includes the target precharge voltage and precharge time.

[0156] S202, the control switch sub-circuit and the DC-DC conversion circuit are forward-biased.

[0157] S203. Control the first terminal of the first switching device to be connected to the third terminal, and control the first terminal of the second switching device to be connected to the third terminal.

[0158] S204: Control the first switch to be turned on and the second switch to be turned off.

[0159] Here, the first switch operates at a first set switching frequency and a first duty cycle. The first set switching frequency and the first duty cycle are determined based on the pre-charge information. The determination method can be found in formulas (2) to (5).

[0160] S205, the energy storage unit charges the first inductor through the first capacitor.

[0161] S206: Control the first switch to be off and the second switch to be on.

[0162] S207, the first inductor precharges the DC-DC conversion circuit.

[0163] Figure 10 is a flowchart of power factor correction circuit energy discharge according to some embodiments. Referring to Figure 10, the control method further includes S301 to S307.

[0164] S301, the control sub-circuit receives the first discharge command and power discharge information.

[0165] The first discharge command instructs the circuit to discharge power to the power factor correction circuit. The power discharge information includes the target discharge voltage and discharge time.

[0166] S302, the control switch sub-circuit and the power factor correction circuit are reverse-biased.

[0167] S303, the control sub-circuit controls the first terminal of the first switching device to be connected to the second terminal, and controls the first terminal of the second switching device to be connected to the second terminal.

[0168] S304 controls the first switch to be turned off and the second switch to be turned on.

[0169] Here, the second switch operates at a second set switching frequency and a second duty cycle. The second set switching frequency and the second duty cycle are determined based on the energy discharge information. The determination method can be found in formulas (6) to (9).

[0170] S305, the power factor correction circuit charges the first inductor.

[0171] S306: Control the first switch to be turned on and the second switch to be turned off.

[0172] S307, the first inductor charges the energy storage unit through the first capacitor.

[0173] Figure 11 is a flowchart of power discharge in a DC-DC conversion circuit according to some embodiments. Referring to Figure 11, the control method further includes S401 to S407.

[0174] S401, the control sub-circuit receives the second discharge command and power discharge information.

[0175] The second discharge command is used to instruct the circuit to discharge power to the DC-DC converter. The power discharge information includes the target discharge voltage and discharge time.

[0176] S402, the control switch sub-circuit is reverse-biased to the DC-DC conversion circuit.

[0177] S403, control the first terminal of the first switching device to be connected to the third terminal, and control the first terminal of the second switching device to be connected to the third terminal.

[0178] S404 controls the first switch to be turned off and the second switch to be turned on.

[0179] Here, the second switch operates at a second set switching frequency and a second duty cycle. The second set switching frequency and the second duty cycle are determined based on the energy discharge information. The determination method can be found in formulas (6) to (9).

[0180] S405, DC-DC converter circuit charges the first inductor.

[0181] S406: Control the first switch to be turned on and the second switch to be turned off.

[0182] S407, The first inductor charges the energy storage unit through the first capacitor.

[0183] Some embodiments of this disclosure also provide a charging device, as shown in FIG12. The charging device 200 includes: a circuit 100, a power factor correction circuit 110, and a DC-DC conversion circuit 120.

[0184] The first terminal A1 of the power factor correction circuit 110 is electrically connected to the first terminal X1 of the circuit 100, and the second terminal A2 of the power factor correction circuit 110 is electrically connected to the second terminal X2 of the circuit.

[0185] The first terminal B1 of the DC-DC converter circuit 120 is electrically connected to the third terminal X3 of the circuit 100, and the second terminal B2 of the DC-DC converter circuit 120 is electrically connected to the fourth terminal X4 of the circuit 100.

[0186] In some embodiments, the charging device 200 described above can be a charging pile or a charging station.

[0187] In some embodiments, the power factor correction circuit 110 includes a third capacitor C3.

[0188] The first terminal of the third capacitor C3 is electrically connected to the first terminal of the power factor correction circuit 110, and the second terminal of the third capacitor C3 is electrically connected to the second terminal of the power factor correction circuit 110.

[0189] The DC-DC converter circuit 120 includes: a fourth capacitor C4.

[0190] The first terminal of the fourth capacitor C4 is electrically connected to the first terminal of the DC-DC converter circuit 120, and the second terminal of the fourth capacitor C4 is electrically connected to the second terminal of the DC-DC converter circuit 120.

[0191] When the energy storage unit 1 precharges the power factor correction circuit 110 or the DC-DC conversion circuit 120, the energy storage unit 1 first charges the first capacitor C1, then turns on the first switching unit 23, and charges the energy storage unit 25 through the first capacitor C1. After the energy storage unit 25 has finished charging, the first switching unit 23 turns off, and then turns on the second switching unit 24. The control sub-circuit 3 controls the first terminal of the first switching device SW1 to be connected to the second terminal, and controls the first terminal of the second switching device SW2 to be connected to the second terminal, so that the energy storage unit 25 precharges the third capacitor C3 in the power factor correction circuit 110. The control sub-circuit 3 controls the first terminal of the first switching device SW1 to be connected to the third terminal, and controls the first terminal of the second switching device SW2 to be connected to the third terminal, so that the energy storage unit 25 precharges the fourth capacitor C4 in the DC-DC conversion circuit 120.

[0192] When the power factor correction circuit 110 or the DC-DC conversion circuit 120 discharges electrical energy, it mainly uses the third capacitor C3 or the fourth capacitor C4 to first turn on the second switching unit 24 to charge the energy storage unit 25. After the energy storage unit 25 has finished charging, the second switching unit 24 is turned off and the first switching unit 23 is turned on. The energy storage unit 25 charges the energy storage section 1, thereby completing the discharge and storage of electrical energy.

[0193] In the description of this specification, exemplary features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0194] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A circuit (100), comprising: Energy storage unit (1) and switching sub-circuit (2); The energy storage unit (1) is electrically connected to the switch sub-circuit (2); The switching sub-circuit (2) is electrically connected to at least one of the power factor correction circuit (110) and the DC-DC conversion circuit (120); The switching sub-circuit (2) is configured to: precharge the power factor correction circuit (110) or the DC-DC conversion circuit (120) using the electrical energy stored in the energy storage unit (1); or store the electrical energy discharged by the power factor correction circuit (110) or the DC-DC conversion circuit (120) in the energy storage unit (1).

2. The circuit (100) according to claim 1, wherein, The switching sub-circuit (2) includes: a boost / buck module (21); The buck-boost module (21) is electrically connected to the energy storage unit (1), and the buck-boost module (21) is also electrically connected to at least one of the power factor correction circuit (110) and the DC-DC conversion circuit (120); The buck-boost module (21) is configured to: transform the voltage provided by the energy storage unit (1) to output a target pre-charge voltage to the power factor correction circuit (110) or the DC-DC converter circuit (120); or transform the voltage discharged by the power factor correction circuit (110) or the DC-DC converter circuit (120) to output a target discharge voltage to the energy storage unit (1).

3. The circuit (100) according to claim 2, wherein, The boost / buck module (21) includes: a first switching unit (23), a second switching unit (24), and an energy storage unit (25); The first end (231) of the first switching unit (23) is electrically connected to the first end (211) of the buck-boost module (21), the second end (232) of the first switching unit (23) is electrically connected to the second end (212) of the buck-boost module (21), the second end (232) of the first switching unit (23) is also electrically connected to the second end (252) of the energy storage unit (25) and the first end (241) of the second switching unit (24), the third end (233) of the first switching unit (23) is electrically connected to the third end (213) of the buck-boost module (21), the third end (233) of the first switching unit (23) is also electrically connected to the first end (251) of the energy storage unit (25); the second end (242) of the second switching unit (24) is electrically connected to the fourth end (214) of the buck-boost module (21); When the first switching unit (23) is turned on and the second switching unit (24) is turned off, the energy storage unit (1) is configured to charge the energy storage unit (25); after the energy storage unit (25) is charged, the first switching unit (23) is turned off and the second switching unit (24) is turned on, and the energy storage unit (25) is configured to precharge the power factor correction circuit (110) or the DC-DC conversion circuit (120); When the first switch unit (23) is off and the second switch unit (24) is on, the power factor correction circuit (110) or the DC-DC conversion circuit (120) discharges electrical energy to charge the energy storage unit (25); after the energy storage unit (25) is charged, the first switch unit (23) is on and the second switch unit (24) is off, and the energy storage unit (25) is configured to charge the energy storage section (1).

4. The circuit (100) according to claim 3, wherein, The first switching unit (23) includes: a first capacitor (C1) and a first switching transistor (Q1); The first end of the first capacitor (C1) is electrically connected to the first end (231) of the first switching unit (23), and the first end of the first capacitor (C1) is also electrically connected to the first end of the first switching transistor (Q1). The second end of the first capacitor (C1) is electrically connected to the second end (232) of the first switching unit (23); the second end of the first switching transistor (Q1) is electrically connected to the third end (233) of the first switching unit (23).

5. The circuit (100) according to claim 3 or 4, wherein, The second switching unit (24) includes: a second switching transistor (Q2); The first end of the second switching transistor (Q2) is electrically connected to the first end (241) of the second switching unit (24), and the second end of the second switching transistor (Q2) is electrically connected to the second end (242) of the second switching unit (24). The energy storage unit (25) includes a first inductor (L1); The first end of the first inductor (L1) is electrically connected to the first end (251) of the energy storage unit (25), and the second end of the first inductor (L1) is electrically connected to the second end (252) of the energy storage unit (25).

6. The circuit (100) according to any one of claims 1 to 5, wherein, The switching sub-circuit (2) further includes: a switching module (22); The switching module (22) is electrically connected to the boost / buck module (21); The switching module (22) is electrically connected to at least one of the power factor correction circuit (110) and the DC-DC conversion circuit (120); The switching module (22) is configured to electrically connect the buck-boost module (21) to the power factor correction circuit (110) to precharge or discharge the power factor correction circuit (110); or, to electrically connect the buck-boost module (21) to the DC-DC converter circuit (120) to precharge or discharge the DC-DC converter circuit (120).

7. The circuit (100) according to claim 6, wherein, The switching module (22) includes: a first switching device (SW1) and a second switching device (SW2); The first terminal (S11) of the first switching device (SW1) is electrically connected to the second terminal (222) of the switching module (22), the second terminal (S12) of the first switching device (SW1) is electrically connected to the third terminal (223) of the switching module (22), and the third terminal (S13) of the first switching device (SW1) is electrically connected to the fifth terminal (225) of the switching module (22). The first end (S21) of the second switching device (SW2) is electrically connected to the first end (221) of the switching module (22), the second end (S22) of the second switching device (SW2) is electrically connected to the fourth end (224) of the switching module (22), and the third end (S23) of the second switching device (SW2) is electrically connected to the sixth end (226) of the switching module (22).

8. The circuit (100) according to claim 7, wherein, The third terminal (223) of the switching module (22) is electrically connected to the first terminal (A1) of the power factor correction circuit (110), and the fourth terminal (224) of the switching module (22) is electrically connected to the second terminal (A2) of the power factor correction circuit (110). The fifth terminal (225) of the switching module (22) is electrically connected to the first terminal (B1) of the DC-DC conversion circuit (120), and the sixth terminal (226) of the switching module (22) is electrically connected to the second terminal (B2) of the DC-DC conversion circuit (120).

9. The circuit (100) according to claim 7 or 8 further comprises: The control sub-circuit (3) is electrically connected to the first switching device (SW1) and the second switching device (SW2); The control sub-circuit (3) is configured to: control the first terminal (S11) and the second terminal (S12) of the first switching device (SW1) to be turned on, and control the first terminal (S21) and the second terminal (S22) of the second switching device (SW2) to be turned on, so as to precharge or discharge the power factor correction circuit (110); or, control the first terminal (S11) and the third terminal (S13) of the first switching device (SW1) to be turned on, and control the first terminal (S21) and the third terminal (S23) of the second switching device (SW2) to be turned on, so as to precharge or discharge the DC-DC conversion circuit (120).

10. The circuit (100) according to any one of claims 2 to 9, wherein, The step-up / step-down module (21) also includes: a second capacitor (C2); The first end of the second capacitor (C2) is electrically connected to the first end (251) of the energy storage unit (25), and the second end of the second capacitor (C2) is electrically connected to the second end (242) of the second switching unit (24).

11. The circuit (100) according to any one of claims 1 to 10, wherein, The energy storage unit (1) includes photovoltaic cells.

12. A charging device (200), comprising: The circuit (100) according to any one of claims 1 to 11; A power factor correction circuit (110), wherein a first terminal of the power factor correction circuit (110) is electrically connected to a first terminal of the circuit (100), and a second terminal of the power factor correction circuit (110) is electrically connected to a second terminal of the circuit (100); and A DC-DC converter circuit (120) is provided, wherein the first end of the DC-DC converter circuit (120) is electrically connected to the third end of the circuit (100), and the second end of the DC-DC converter circuit (120) is electrically connected to the fourth end of the circuit (100).

13. The charging device (200) according to claim 12, wherein, The power factor correction circuit (110) includes: a third capacitor (C3); the first end of the third capacitor (C3) is electrically connected to the first end of the power factor correction circuit (110), and the second end of the third capacitor (C3) is electrically connected to the second end of the power factor correction circuit (110). The DC-DC converter circuit (120) includes: a fourth capacitor (C4); the first end of the fourth capacitor (C4) is electrically connected to the first end of the DC-DC converter circuit (120), and the second end of the fourth capacitor (C4) is electrically connected to the second end of the DC-DC converter circuit (120).

14. A control method applied to a circuit (100) according to any one of claims 1 to 11; Controlling the switching sub-circuit (2) to conduct in the forward or reverse direction with the power factor correction circuit (110) to precharge or discharge the power factor correction circuit (110); or, Control the switching sub-circuit (2) to conduct in the forward or reverse direction with the DC-DC conversion circuit (120) to precharge or discharge the DC-DC conversion circuit (120).

15. The control method according to claim 14, wherein, The switching sub-circuit (2) includes a first switching device (SW1) and a second switching device (SW2); The control of the switching sub-circuit (2) and the power factor correction circuit (110) to conduct in the forward or reverse direction includes: controlling the first terminal (S11) and the second terminal (S12) of the first switching device (SW1) to conduct, and controlling the first terminal (S21) and the second terminal (S22) of the second switching device (SW2) to conduct, so as to precharge or discharge the power factor correction circuit (110); The control of the switching sub-circuit (2) and the DC-DC conversion circuit (120) to conduct in the forward or reverse direction includes: controlling the first terminal (S11) and the third terminal (S13) of the first switching device (SW1) to conduct, and controlling the first terminal (S21) and the third terminal (S23) of the second switching device (SW2) to conduct, so as to precharge or discharge the DC-DC conversion circuit (120).

16. The control method according to claim 14, wherein, The switching sub-circuit (2) includes: a first capacitor (C1), a first switching transistor (Q1), a second switching transistor (Q2), and a first inductor (L1); Controlling the switching sub-circuit (2) to be forward-biased with the power factor correction circuit (110) or the DC-DC conversion circuit (120) includes: In the first stage, the first switch (Q1) is turned on and the second switch (Q2) is turned off; the energy storage unit (1) charges the first inductor (L1) through the first capacitor (C1); In the second stage, the first switch (Q1) is turned off and the second switch (Q2) is turned on; the first inductor (L1) precharges the power factor correction circuit (110) or the DC-DC conversion circuit (120).

17. The control method according to claim 16, wherein, During the process of controlling the forward conduction of the switching sub-circuit (2) and the power factor correction circuit (110) or the DC-DC conversion circuit (120), the method further includes: The first switch (Q1) is controlled to operate at a first set switching frequency and a first duty cycle.

18. The control method according to claim 17, wherein, Before controlling the forward conduction of the switching subcircuit (2) and the power factor correction circuit (110) or the DC-DC converter circuit (120), the method further includes: Receive pre-charge information, which includes a target pre-charge voltage and a pre-charge time; The first set switching frequency and the first duty cycle are determined based on the pre-charge information.

19. The control method according to claim 14, wherein, The switching sub-circuit (2) includes: a first capacitor (C1), a first switching transistor (Q1), a second switching transistor (Q2), and a first inductor (L1); Controlling the switching sub-circuit (2) to conduct in reverse with the power factor correction circuit (110) or the DC-DC conversion circuit (120) includes: In the first stage, the first switch (Q1) is turned off and the second switch (Q2) is turned on; the power factor correction circuit (110) or the DC-DC conversion circuit (120) charges the first inductor (L1); In the second stage, the first switch (Q1) is turned on and the second switch (Q2) is turned off; the first inductor (L1) charges the energy storage unit (1) through the first capacitor (C1).

20. The control method according to claim 19, wherein, In the process of controlling the switching sub-circuit (2) to conduct in reverse with the power factor correction circuit (110) or the DC-DC conversion circuit (120), the method further includes: The second switch (Q2) is controlled to operate at a second set switching frequency and a second duty cycle.

21. The control method according to claim 20, wherein, Before controlling the switching subcircuit (2) to conduct in reverse with the power factor correction circuit (110) or the DC-DC conversion circuit (120), the method further includes: Receive power discharge information, the power discharge information including target discharge voltage and discharge time; The second set switching frequency and the second duty cycle are determined based on the energy discharge information.

22. The control method according to any one of claims 14 to 21, wherein, Before controlling the switching sub-circuit (2) to be forward-biased and the power factor correction circuit (110), the method further includes: receiving a first pre-charge instruction, the first pre-charge instruction being used to instruct the circuit (100) to pre-charge the power factor correction circuit (110); Before controlling the switching sub-circuit (2) to conduct in reverse with the power factor correction circuit (110), the method further includes: receiving a first discharge command, the first discharge command being used to instruct the circuit (100) to discharge electrical energy to the power factor correction circuit (110); or Before controlling the switching sub-circuit (2) to be forward-biased with the DC-DC converter circuit (120), the method further includes: receiving a second pre-charge instruction, the second pre-charge instruction being used to instruct the circuit (100) to pre-charge the DC-DC converter circuit (120); Before controlling the switching sub-circuit (2) to conduct in reverse with the DC-DC converter circuit (120), the method further includes: receiving a second discharge command, the second discharge command being used to instruct the circuit (100) to discharge electrical energy to the DC-DC converter circuit (120).

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