Battery bidirectional circuit and load power supply device

Abstract

The invention provides a battery bidirectional circuit and a load power supply device. The battery bidirectional circuit comprises a first circuit and a second circuit. The first circuit comprises a first inductor, a first switching tube and a second switching tube; the second circuit comprises a second inductor, a third switching tube and a fourth switching tube; the first end of the first inductor and the first end of the third switching tube serve as first ports; a contact between the second end of the first inductor and the first end of the second switching tube is connected with a contact between the second end of the third switching tube and the first end of the fourth switching tube through the first switching tube and the second inductor; a contact between the first switch tube and the second inductor is used as a second port and a fifth port; the second end of the second switch tube is used as a third port, and the second end of the fourth switch tube is used as a fourth port; wherein the first port and the second port are used for connecting a battery pack, and the third port, the fourth port and the fifth port are used for connecting a direct current bus. The size of the circuit in the load power supply device can be reduced.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a battery bidirectional circuit and a load power supply device. Background Art

[0002] In load power supply devices such as photovoltaic power generation systems and uninterruptible power supplies (UPS), photovoltaic power generation, mains power and battery packs are used to power the DC bus, and the DC power is converted using a conversion circuit connected to the DC bus to power the load. In non-battery power supply mode, photovoltaic power generation or mains power input is used to power the DC bus, so that the load can work normally and the battery pack is charged at the same time; when photovoltaic power generation or mains power input fails, it switches to battery power supply mode and powers the DC bus through the battery pack to ensure that the load is powered continuously.

[0003] In the related art, the battery pack is usually charged through the battery charging circuit, and the electric energy stored in the battery pack is provided to the DC bus through the battery discharging circuit. It is necessary to set two circuits, a battery charging circuit and a discharging circuit, between the battery pack and the DC bus, resulting in a larger load power supply device. Summary of the invention

[0004] The embodiments of the present application provide a battery bidirectional circuit and a load power supply device to reduce the volume of the circuit in the load power supply device.

[0005] In a first aspect, an embodiment of the present application provides a battery bidirectional circuit, which is applied to a load power supply device including a battery pack and a DC bus; the DC bus includes a positive bus, a negative bus and a neutral line; the battery bidirectional circuit includes a first circuit and a second circuit; the first circuit includes a first inductor, a first switch tube and a second switch tube; the second circuit includes a second inductor, a third switch tube and a fourth switch tube;

[0006] The first end of the first inductor and the first end of the third switch tube serve as a first port of the battery bidirectional circuit;

[0007] A connection point between the second end of the first inductor and the first end of the second switch tube is connected to a connection point between the second end of the third switch tube and the first end of the fourth switch tube through the first switch tube and the second inductor;

[0008] The connection point between the first switch tube and the second inductor serves as the second port and the fifth port of the battery bidirectional circuit; the second end of the second switch tube serves as the third port of the battery bidirectional circuit, and the second end of the fourth switch tube serves as the fourth port of the battery bidirectional circuit;

[0009] The first port and the second port are used to connect a battery pack, the third port and the fourth port are used to connect a positive bus bar and a negative bus bar, and the fifth port is used to connect a neutral line.

[0010] In a possible implementation, when the first port is used to connect the positive electrode of the battery pack and the second port is used to connect the negative electrode of the battery pack, the third port is connected to the positive bus bar and the fourth port is connected to the negative bus bar;

[0011] When the first port is used to connect the negative electrode of the battery pack and the second port is used to connect the positive electrode of the battery pack, the third port is connected to the negative bus bar and the fourth port is connected to the positive bus bar.

[0012] In a possible implementation, a positive capacitor is connected between the positive bus and the neutral line, and a negative capacitor is connected between the neutral line and the negative bus;

[0013] When the load power supply device is in a non-battery power supply mode, when there is a voltage difference between the positive capacitor and the negative capacitor, the capacitor with a higher voltage between the positive capacitor and the negative capacitor charges the battery pack; or, the positive capacitor and the negative capacitor charge the battery pack;

[0014] In which, in a charging cycle, the first charging energy is greater than the second charging energy, the first charging energy is the energy used by the capacitor with a higher voltage between the positive capacitor and the negative capacitor to charge the battery pack, and the second charging energy is the energy used by the capacitor with a lower voltage between the positive capacitor and the negative capacitor to charge the battery pack.

[0015] In a possible implementation, when there is a voltage difference between the positive capacitor and the negative capacitor in a non-battery power supply mode, the load power supply device controls the two switch tubes of the circuit connected to the capacitor with a higher voltage in the battery bidirectional circuit to be alternately turned on, and controls the main switch tube of the circuit connected to the capacitor with a lower voltage in the battery bidirectional circuit to be turned off, so that the capacitor with a higher voltage among the positive capacitor and the negative capacitor charges the battery pack; wherein the main switch tube of the first circuit is the second switch tube, and the main switch tube of the second circuit is the fourth switch tube.

[0016] In one possible implementation, when there is a voltage difference between the positive capacitor and the negative capacitor in a non-battery power supply mode, the load power supply device controls the first switch tube and the second switch tube to be alternately turned on, and controls the third switch tube and the fourth switch tube to be alternately turned on, so that the positive capacitor and the negative capacitor charge the battery pack; wherein, in a charging cycle, the first charging energy is greater than the second charging energy.

[0017] In a possible implementation, in the non-battery power supply mode, when the positive capacitor and the negative capacitor are balanced, the load power supply device controls the first switch tube and the second switch tube to be alternately turned on, and controls the third switch tube and the fourth switch tube to be alternately turned on, so that the positive capacitor and the negative capacitor charge the battery pack; wherein, in one charging cycle, the energy charged by the positive capacitor and the negative capacitor for the battery pack is equal;

[0018] In the battery power supply mode, the load power supply device controls the first switch tube and the second switch tube to be alternately turned on, and controls the third switch tube and the fourth switch tube to be alternately turned on, so that the battery pack charges the positive capacitor and the negative capacitor; wherein, in a charging cycle, the energy charged by the battery pack for the positive capacitor and the negative capacitor is equal.

[0019] In a possible implementation, a positive capacitor is connected between the positive bus and the neutral line, and a negative capacitor is connected between the neutral line and the negative bus;

[0020] The voltage of the battery pack is greater than a second voltage of the positive capacitor or the negative capacitor connected to the second circuit;

[0021] When the load power supply device is in a non-battery power supply mode, when the second voltage is greater than the first voltage of the positive capacitor or the negative capacitor connected to the first circuit, or when the power of the load is less than a preset power, the positive capacitor or the negative capacitor connected to the second circuit is boosted by the second circuit to charge the battery pack;

[0022] When the load power supply device is in the battery power supply mode, the battery pack charges the positive capacitor or the negative capacitor connected to the second line by reducing the voltage of the second line.

[0023] In a second aspect, an embodiment of the present application provides a load power supply device, including a power input module, a DC bus, a conversion circuit, a battery pack, and a battery bidirectional circuit as described in the first aspect or any possible implementation of the first aspect;

[0024] The DC bus is connected to the power input module, and the DC bus is connected to the load through the conversion circuit; wherein the DC bus includes a positive bus, a negative bus and a neutral line;

[0025] The battery bidirectional circuit is connected to the battery pack through the first port and the second port on the battery side, and is connected to the positive bus and the negative bus through the third port and the fourth port on the bus side, and the fifth port is connected to the neutral line.

[0026] In a possible implementation, the load power supply device further includes a controller; the power input module includes a rectifier circuit; the input end of the rectifier circuit is used to connect to a mains input;

[0027] The controller is used to:

[0028] When the AC power input from the mains is normal, entering the mains power supply mode;

[0029] When the AC power input from the mains fails, the system enters the battery power supply mode.

[0030] In a possible implementation, the load power supply device further includes a controller; the power input module includes a DC-DC conversion circuit; the input end of the DC-DC conversion circuit is used to connect to a photovoltaic power generation input;

[0031] The controller is used to:

[0032] When the DC power input by photovoltaic power generation is normal, it enters photovoltaic power generation mode;

[0033] When the DC power input from photovoltaic power generation fails, the system enters battery power supply mode.

[0034] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0035] In the embodiment of the present application, the first port and the second port of the battery bidirectional circuit are connected to the battery pack, and the third port, the fourth port and the fifth port are connected to the DC bus. Through the first switch tube, the second switch tube, the third switch tube and the fourth switch tube in the battery bidirectional circuit, the battery bidirectional circuit can be used to charge the battery pack, and the battery bidirectional circuit can be used to provide the electric energy stored in the battery pack to the DC bus. The battery bidirectional circuit can be used to charge and discharge the battery pack without setting up a charging circuit and a discharging circuit respectively, thereby reducing the volume of the circuit. At the same time, the battery bidirectional circuit includes a first circuit and a second circuit, and the first circuit and the second circuit are respectively connected to the positive bus and the negative bus, so that the battery pack can supply power to the positive bus or the negative bus in the DC bus through one circuit of the battery bidirectional circuit, without satisfying the entire bus, and the cooperation of the first circuit and the second circuit can realize the power supply of the positive bus and the negative bus, which can reduce the power of the battery bidirectional circuit, so that the power of the battery bidirectional circuit does not need to meet the rated power of the load power supply device, thereby further reducing the volume and cost of the battery bidirectional circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 is a schematic diagram of the structure of a battery bidirectional circuit provided in an embodiment of the present application;

[0038] Figure 2 is a schematic diagram of the structure of a load power supply device provided in an embodiment of the present application;

[0039] Figure 3 is a first circuit structure diagram of a battery bidirectional circuit provided in an embodiment of the present application;

[0040] Figure 4 is a second circuit structure diagram of a battery bidirectional circuit provided in an embodiment of the present application;

[0041] Figure 5 This is a circuit structure diagram of a first single-phase uninterruptible power supply provided in an embodiment of the present application;

[0042] Figure 6 is a first working schematic diagram of a battery bidirectional circuit in a non-battery power supply mode provided by an embodiment of the present application;

[0043] Figure 7 is a second working schematic diagram of a battery bidirectional circuit in a non-battery power supply mode provided by an embodiment of the present application;

[0044] Figure 8 is a circuit structure diagram of a second single-phase uninterruptible power supply provided in an embodiment of the present application;

[0045] Fig. 9 is a first working schematic diagram of a battery bidirectional circuit in a battery power supply mode provided by an embodiment of the present application;

[0046] Fig.10 is a second working schematic diagram of a battery bidirectional circuit in a battery power supply mode provided by an embodiment of the present application;

[0047] Fig.11 This is a circuit structure diagram of a first three-phase uninterruptible power supply provided in an embodiment of the present application;

[0048] Fig.12 It is a circuit structure diagram of a third single-phase uninterruptible power supply provided in an embodiment of the present application;

[0049] Fig.13 is a circuit structure diagram of a second three-phase uninterruptible power supply provided in an embodiment of the present application;

[0050] Fig.14 is a circuit structure diagram of a fourth single-phase uninterruptible power supply provided in an embodiment of the present application;

[0051] Fig.15 It is a structural schematic diagram of the first photovoltaic power generation system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0053] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0054] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0055] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0056] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0057] In addition, the “plurality” mentioned in the embodiments of the present application should be interpreted as two or more.

[0058] The inventors have found that a load power supply device is usually provided with a battery pack, which can be used to supply power, and a charging circuit and a discharging circuit of the battery are also required to ensure the normal use of the battery pack. However, providing both a charging circuit and a discharging circuit in the load power supply device will result in a larger volume of the load power supply device.

[0059] In addition, the inventors have also discovered that when a battery pack is powered through a discharge circuit, the power of the discharge circuit needs to meet the rated power of the load power supply device. For example, in an uninterruptible power supply, the discharge circuit of the battery needs to meet the rated power of the uninterruptible power supply. The electronic components required for the discharge circuit have a large power requirement, which is not conducive to reducing volume and cost.

[0060] In order to reduce the volume and cost of the circuit, in the embodiment of the present application, a battery bidirectional circuit is provided to charge and discharge the battery pack, wherein, by setting a first inductor, a second inductor, a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, the battery bidirectional circuit can be used to charge the battery pack, and the electric energy stored in the battery pack can be provided to the DC bus, and the battery pack can be charged and discharged through the battery bidirectional circuit, without setting up a charging circuit and a discharging circuit respectively, thereby reducing the volume of the circuit. At the same time, by connecting the positive bus and the negative bus respectively through the first circuit and the second circuit, the battery pack can supply power to the positive bus or the negative bus in the DC bus through one circuit in the battery bidirectional circuit, thereby reducing the power of the battery bidirectional circuit and the power of the electronic device selection, thereby reducing the volume and cost.

[0061] In order to make the purpose, technical solutions and advantages of the present application clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0062] Figure 1 The schematic diagram of the structure of the battery bidirectional circuit provided in the embodiment of the present application, the battery bidirectional circuit can be applied to a load power supply device including a battery pack and a DC bus, wherein the DC bus includes a positive bus +BUS, a negative bus -BUS and a neutral line N. The battery bidirectional circuit includes a first circuit and a second circuit; the first circuit includes a first inductor L1, a first switch tube Q1 and a second switch tube Q2; the second circuit includes a second inductor L2, a third switch tube Q3 and a fourth switch tube Q4.

[0063] The first end of the first inductor L1 and the first end of the third switch tube Q3 serve as the first port D01 of the battery bidirectional circuit.

[0064] A connection point between the second end of the first inductor L1 and the first end of the second switch tube Q2 is connected to a connection point between the second end of the third switch tube Q3 and the first end of the fourth switch tube Q4 through the first switch tube Q1 and the second inductor L2.

[0065] The connection point between the first switch tube Q1 and the second inductor L2 serves as the second port D02 and the fifth port D05 of the battery bidirectional circuit; the second end of the second switch tube Q2 serves as the third port D03 of the battery bidirectional circuit, and the second end of the fourth switch tube Q4 serves as the fourth port D04 of the battery bidirectional circuit.

[0066] The first port D01 and the second port D02 are used to connect the battery pack, the third port D03 and the fourth port D04 are used to connect the positive bus +BUS and the negative bus -BUS, and the fifth port D05 is used to connect the neutral line N.

[0067] Here, the first circuit includes a first inductor L1, a first switch tube Q1 and a second switch tube Q2, see Figure 2 The structural diagram of the load power supply device shown is an application scenario diagram of a battery bidirectional circuit, in which the first circuit can be connected to the positive electrode BAT+ and the negative electrode BAT- of the battery pack through the first port D01 and the second port D02, connected to the positive bus +BUS or the negative bus -BUS through the third port D03, and connected to the neutral line N through the fifth port D05. The first circuit in the battery bidirectional circuit is used to connect the battery pack to the positive bus +BUS or the negative bus -BUS of the DC bus, so that the first circuit can be used to charge the battery pack and release the electric energy of the battery pack to the positive bus +BUS or the negative bus -BUS.

[0068] The second circuit includes a second inductor L2, a third switch tube Q3 and a fourth switch tube Q4. Figure 2 In the application scenario diagram of the battery bidirectional circuit shown in the figure, the second circuit can be connected to the positive electrode BAT+ and the negative electrode BAT- of the battery pack through the first port D01 and the second port D02, connected to the positive bus +BUS or the negative bus -BUS through the fourth port D04, and connected to the neutral line N through the fifth port D05. The second circuit in the battery bidirectional circuit is used to connect the battery pack to the positive bus +BUS or the negative bus -BUS of the DC bus, so that the second circuit can be used to charge the battery pack and release the electric energy of the battery pack to the positive bus +BUS or the negative bus -BUS.

[0069] In addition, in the battery power supply mode, the battery pack discharges to the positive bus +BUS or the negative bus -BUS through the first circuit. The selected power of the electronic devices in the first circuit only needs to meet half the power of the DC bus, and does not need to meet the power of the entire DC bus. The voltage stress in the first circuit can be reduced, and the selected power of the electronic devices in the first circuit can be reduced, thereby reducing the circuit volume.

[0070] Similarly, the battery pack also discharges to the positive bus +BUS or the negative bus -BUS through the second circuit. The selected power of the electronic devices in the second circuit only needs to meet half the power of the DC bus, and does not need to meet the power of the entire DC bus. The voltage stress in the second circuit can be reduced, and the selected power of the electronic devices in the second circuit can be reduced, thereby reducing the circuit volume.

[0071] Furthermore, the battery pack discharges to the positive bus +BUS and the negative bus -BUS through the first line and the second line respectively, which can further reduce the boost ratio of the battery pack supplying power to the DC bus, or further reduce the voltage of the battery pack used.

[0072] For example, the voltage difference between the positive and negative buses in the DC bus is 400V. When the boost ratio is 2, a conventional discharge circuit is used to discharge the battery pack directly to the positive and negative buses, and the voltage of the battery pack needs to be at least 200V. However, when the battery bidirectional circuit provided in this embodiment is used, the voltage of the battery pack only needs to be 100V, which can reduce the voltage of the battery pack and improve battery safety.

[0073] For example, when the voltage difference between the positive and negative buses in the DC bus is 400V and the voltage of the battery pack is 100V, a conventional discharge circuit is used to discharge the battery pack directly to the positive and negative buses, and the required boost ratio is 4; when the battery bidirectional circuit provided in this embodiment is used, the battery pack is discharged to half of the DC bus through the first circuit and the second circuit respectively, and the required boost ratio is 2.

[0074] In the embodiment of the present application, the first port and the second port of the battery bidirectional circuit are connected to the battery pack, and the third port, the fourth port and the fifth port are connected to the DC bus. Through the first switch tube, the second switch tube, the third switch tube and the fourth switch tube in the battery bidirectional circuit, the battery bidirectional circuit can be used to charge the battery pack, and the battery bidirectional circuit can be used to provide the electric energy stored in the battery pack to the DC bus. The battery bidirectional circuit can be used to charge and discharge the battery pack without setting up a charging circuit and a discharging circuit respectively, thereby reducing the volume of the circuit. At the same time, the battery bidirectional circuit includes a first circuit and a second circuit, and the first circuit and the second circuit are respectively connected to the positive bus and the negative bus, so that the battery pack can supply power to the positive bus or the negative bus in the DC bus through one circuit of the battery bidirectional circuit, without satisfying the entire bus, and the cooperation of the first circuit and the second circuit can realize the power supply of the positive bus and the negative bus, which can reduce the power of the battery bidirectional circuit, so that the power of the battery bidirectional circuit does not need to meet the rated power of the load power supply device, thereby further reducing the volume and cost of the battery bidirectional circuit.

[0075] In some embodiments, see Figure 3In the first circuit structure diagram of the battery bidirectional circuit shown, when the first port D01 is used to connect the positive electrode BAT+ of the battery pack and the second port D02 is used to connect the negative electrode BAT- of the battery pack, the third port D03 is connected to the positive bus +BUS and the fourth port D04 is connected to the negative bus -BUS.

[0076] In this embodiment, the battery pack is connected to the positive bus +BUS in the DC bus through a first line in the battery bidirectional circuit, and is connected to the negative bus -BUS in the DC bus through a second line.

[0077] In other embodiments, see Figure 4 In the second circuit structure diagram of the battery bidirectional circuit shown in the figure, when the first port D01 is used to connect the negative electrode BAT- of the battery pack and the second port D02 is used to connect the positive electrode BAT+ of the battery pack, the third port D03 is connected to the negative bus -BUS and the fourth port D04 is connected to the positive bus +BUS.

[0078] In this embodiment, the battery pack is connected to the negative bus -BUS in the DC bus through a first line in the battery bidirectional circuit, and is connected to the positive bus +BUS in the DC bus through a second line.

[0079] The above are two ways of connecting the battery bidirectional circuit. The first circuit is a positive phase circuit, in which the high voltage port on the battery side corresponds to the high voltage port on the bus side, and the low voltage port on the battery side corresponds to the low voltage port on the bus side; the second circuit is a negative phase circuit, in which the high voltage port on the battery side corresponds to the low voltage port on the bus side, and the low voltage port on the battery side corresponds to the high voltage port on the bus side.

[0080] Since the battery pack can be discharged to the positive bus +BUS or the negative bus -BUS through the first circuit, it can also be discharged to the positive bus +BUS or the negative bus -BUS through the second circuit. Correspondingly, the positive bus +BUS can charge the battery pack through the first circuit or the second circuit, and the negative bus -BUS can also charge the battery pack through the first circuit or the second circuit. Based on this, the inventor of the present application considers that the function of the battery bidirectional circuit can be further increased so that the battery bidirectional circuit can achieve the function of balancing the positive and negative bus bars, that is, the battery bidirectional circuit provided in this embodiment realizes the function of the balancing bridge circuit, so that the balancing bridge circuit in the load power supply device can be removed, and the volume and cost of the load power supply device can be further reduced.

[0081] In some embodiments, Figure 2 As shown, a positive capacitor C11 is connected between the positive bus +BUS and the neutral line N, and a negative capacitor C12 is connected between the neutral line N and the negative bus -BUS.

[0082] When the load power supply device is in a non-battery power supply mode, such as a photovoltaic power supply mode or a mains power supply mode, when there is a voltage difference between the positive capacitor C11 and the negative capacitor C12, the capacitor with a higher voltage among the positive capacitor C11 and the negative capacitor C12 charges the battery pack, which can reduce the energy of the capacitor with a higher voltage among the positive capacitor C11 and the negative capacitor C12, thereby balancing the positive capacitor C11 and the negative capacitor C12.

[0083] Alternatively, when there is a voltage difference between the positive capacitor C11 and the negative capacitor C12, the positive capacitor C11 and the negative capacitor C12 may charge the battery pack; wherein, in a charging cycle, the first charging energy is greater than the second charging energy, the first charging energy is the energy of the positive capacitor C11 and the negative capacitor C12 with a higher voltage to charge the battery pack, and the second charging energy is the energy of the positive capacitor C11 and the negative capacitor C12 with a lower voltage to charge the battery pack. Here, the first charging energy is greater than the second charging energy, so that the capacitor with a higher voltage among the positive capacitor C11 and the negative capacitor C12 can provide more energy to the battery pack, thereby balancing the positive capacitor C11 and the negative capacitor C12.

[0084] Based on this, the function of the balanced bridge circuit can be realized by the battery bidirectional circuit, so that the setting of the balanced bridge circuit can be reduced in the load power supply device, and the volume and cost of the circuit can be further reduced.

[0085] The above description is made from the perspective of the positive capacitor C11 and the negative capacitor C12. The specific control of charging the battery pack by the positive capacitor C11 and the negative capacitor C12 is described below.

[0086] Optionally, the control method of charging the battery pack with the capacitor having a higher voltage among the positive capacitor C11 and the negative capacitor C12 may be as follows:

[0087] When the load power supply device is in the non-battery power supply mode, when there is a voltage difference between the positive capacitor C11 and the negative capacitor C12, the two switch tubes of the circuit connected to the capacitor with a higher voltage among the positive capacitor C11 and the negative capacitor C12 in the battery bidirectional circuit are controlled to be alternately turned on, and the main switch tube of the circuit connected to the capacitor with a lower voltage among the positive capacitor C11 and the negative capacitor C12 in the battery bidirectional circuit is controlled to be turned off, so that the capacitor with a higher voltage among the positive capacitor C11 and the negative capacitor C12 charges the battery pack; wherein the main switch tube of the first circuit is the second switch tube Q2, and the main switch tube of the second circuit is the fourth switch tube Q4.

[0088] In this embodiment, Figure 5 The first single-phase uninterruptible power supply shown is used for explanation, wherein the battery bidirectional circuit provided by this embodiment is adopted in the single-phase uninterruptible power supply, the first line of the battery bidirectional circuit is connected to the positive capacitor C11, and the second line is connected to the negative capacitor C12.

[0089] If the voltage of the positive capacitor C11 is greater than the voltage of the negative capacitor C12, the first switch tube Q1 and the second switch tube Q2 in the first circuit can be controlled to be alternately turned on, and the fourth switch tube Q4 in the second circuit can be controlled to be turned off. Figure 6 As shown in the first working schematic diagram of the battery bidirectional circuit in the non-battery power supply mode, when the second switch tube Q2 is turned on, the current flows through the second switch tube Q2 and the first inductor L1 to charge the battery pack, see Figure 6 Path A in the circuit; when the second switch tube Q2 is turned off, the electric energy stored in the first inductor L1 charges the battery pack. Here, the current flows through the diode in the first switch tube to form a complete loop. Figure 6 The B path in .

[0090] If the voltage of the negative capacitor C12 is greater than the voltage of the positive capacitor C11, the third switch tube Q3 and the fourth switch tube Q4 in the second circuit can be controlled to be turned on alternately, and the second switch tube Q2 in the first circuit can be controlled to be turned off. Figure 7 As shown in the second working schematic diagram of the battery bidirectional circuit in the non-battery power supply mode, when the fourth switch tube Q4 is turned on, the current flows through the fourth switch tube Q4 and the second inductor L2 to charge the second inductor L2, see Figure 7 Path A in the circuit; when the fourth switch tube Q4 is turned off, the electric energy stored in the second inductor L2 charges the battery pack. Here, the current flows through the diode in the third switch tube to form a complete loop. Figure 7 The B path in .

[0091] Optionally, when there is a voltage difference between the positive capacitor C11 and the negative capacitor C12, the control method of charging the battery pack by the positive capacitor C11 and the negative capacitor C12 is as follows:

[0092] In the non-battery power supply mode, when there is a voltage difference between the positive capacitor C11 and the negative capacitor C12, the load power supply device controls the first switch tube Q1 and the second switch tube Q2 to be alternately turned on, and controls the third switch tube Q3 and the fourth switch tube Q4 to be alternately turned on, so that the positive capacitor C11 and the negative capacitor C12 charge the battery pack; wherein, in a charging cycle, the first charging energy is greater than the second charging energy.

[0093] In this embodiment, Figure 8 The second single-phase uninterruptible power supply shown is used for explanation, wherein the first line of the battery bidirectional circuit is connected to the negative capacitor C12, and the second line is connected to the positive capacitor C11.

[0094] If the voltage of the positive capacitor C11 is greater than the voltage of the negative capacitor C12, the first switch tube Q1 and the second switch tube Q2 in the first circuit can be controlled to be alternately turned on, and the third switch tube Q3 and the fourth switch tube Q4 in the second circuit can be controlled to be alternately turned on. When the third switch tube Q3 and the fourth switch tube Q4 in the second circuit are alternately turned on, the energy charged by the positive capacitor C11 for the battery pack is the first charging energy; when the first switch tube Q1 and the second switch tube Q2 in the first circuit are alternately turned on, the energy charged by the negative capacitor C12 for the battery pack is the second charging energy, and the first charging energy is greater than the second charging energy.

[0095] Here, when the fourth switch tube Q4 is turned on, the current flows through the fourth switch tube Q4 and the second inductor L2 to charge the battery pack; when the fourth switch tube Q4 is turned off, the electric energy stored in the second inductor L2 charges the battery pack, wherein the current flows through the diode in the third switch tube Q3 to form a complete loop. The current path here can be referred to Figure 7 Path A and Path B in .

[0096] When the second switch tube Q2 is turned on, the current flows through the second switch tube Q2 and the first inductor L1 to charge the battery pack; when the second switch tube Q2 is turned off, the electric energy stored in the first inductor L1 charges the battery pack, wherein the current flows through the diode in the first switch tube Q1 to form a complete loop. The current path here can be referred to Figure 6 Path A and Path B in .

[0097] If the voltage of the negative capacitor C12 is greater than the voltage of the positive capacitor C11, when the first switch tube Q1 and the second switch tube Q2 in the first circuit are alternately turned on, the energy charged by the negative capacitor C12 for the battery pack is the first charging energy; when the third switch tube Q3 and the fourth switch tube Q4 in the second circuit are alternately turned on, the energy charged by the positive capacitor C11 for the battery pack is the second charging energy, and the first charging energy at this time is greater than the second charging energy.

[0098] For the control of the switch tube and the current flow direction, reference can be made to the above-mentioned situation where "the voltage of the positive capacitor C11 is greater than the voltage of the negative capacitor C12", which will not be elaborated here.

[0099] When the load power supply device is in non-battery power supply mode, there will still be a balance between the positive capacitor C11 and the negative capacitor C12, which is described in detail below:

[0100] Optionally, in the non-battery power supply mode, when the positive capacitor C11 and the negative capacitor C12 are balanced, the load power supply device controls the first switch tube Q1 and the second switch tube Q2 in the first circuit to be alternately turned on, and controls the third switch tube Q3 and the fourth switch tube Q4 in the second circuit to be alternately turned on, so that the positive capacitor C11 and the negative capacitor C12 charge the battery pack; wherein, in a charging cycle, the energy charged by the positive capacitor C11 and the negative capacitor C12 for the battery pack is equal.

[0101] In this embodiment, by controlling the positive capacitor C11 and the negative capacitor C12 to charge the battery pack with equal energy, the positive capacitor C11 and the negative capacitor C12 can charge the battery pack in a balanced manner, thereby maintaining a balance between the positive capacitor C11 and the negative capacitor C12.

[0102] In addition, in the battery power supply mode, the load power supply device can control the first switch tube Q1 and the second switch tube Q2 to be alternately turned on, and control the third switch tube Q3 and the fourth switch tube Q4 to be alternately turned on, so that the battery pack charges the positive capacitor C11 and the negative capacitor C12; wherein, in one charging cycle, the energy charged by the battery pack for the positive capacitor C11 and the negative capacitor C12 is equal.

[0103] In this embodiment, Figure 5 The circuit structure diagram of the first single-phase uninterruptible power supply is shown as follows: Fig. 9 The first working schematic diagram of the battery bidirectional circuit in the battery power supply mode is shown. In the first circuit, when the first switch tube Q1 is turned on, the current flows through the first switch tube Q1 and the first inductor L1 to charge the battery pack. Fig. 9 Path A in the circuit; when the first switch tube Q1 is turned off, the electric energy stored in the first inductor L1 charges the battery pack, wherein the current flows through the diode in the second switch tube Q2 to form a complete loop, see Fig. 9 The B path in .

[0104] like Fig.10 The second working schematic diagram of the battery bidirectional circuit in the battery power supply mode is shown. In the second circuit, when the third switch tube Q3 is turned on, the current flows through the third switch tube Q3 and the second inductor L2 to charge the battery pack. Fig.10 When the third switch tube Q3 is turned off, the electric energy stored in the second inductor L2 charges the battery pack, wherein the current flows through the diode in the fourth switch tube Q4 to form a complete loop, see Fig.10 The B path in .

[0105] In some other embodiments, a positive capacitor C11 is connected between the positive bus +BUS and the neutral line N, and a negative capacitor C12 is connected between the neutral line N and the negative bus -BUS.

[0106] The voltage of the battery pack is greater than the second voltage of the positive capacitor C11 or the negative capacitor C12 connected to the second circuit. The second circuit is mainly used for explanation, that is, the voltage on the battery side of the second circuit is higher than the voltage on the bus side of the second circuit.

[0107] In the non-battery power supply mode, when the second voltage of the load power supply device is greater than the first voltage of the positive capacitor C11 or the negative capacitor C12 connected to the first circuit, or when the power of the load is less than the preset power, the positive capacitor C11 or the negative capacitor C12 connected to the second circuit charges the battery pack through the second circuit boost.

[0108] Here, in the non-battery power supply mode, when the second voltage is greater than the first voltage, in order to make the positive capacitor C11 and the negative capacitor C12 tend to balance, it is necessary to charge the capacitor with higher voltage between the positive capacitor C11 and the negative capacitor C12 to charge the battery pack, that is, the positive capacitor C11 or the negative capacitor C12 connected to the second circuit.

[0109] Since the voltage of the battery pack is greater than the second voltage, the positive capacitor C11 or the negative capacitor C12 corresponding to the second voltage needs to be boosted to charge the battery pack. Accordingly, in this embodiment, the second circuit is an inverting circuit, that is, the positive capacitor C11 or the negative capacitor C12 connected to the second circuit can be boosted through the second circuit.

[0110] When the power of the load is less than the preset power, that is, when the load power supply device is unloaded or lightly loaded, the balance of the positive and negative bus bars can be self-restored. At this time, in order to charge the battery pack, the positive capacitor C11 or the negative capacitor C12 connected to the second circuit can be boosted through the second circuit to charge the battery pack.

[0111] In addition, when the load power supply device is in the battery power supply mode and the voltage of the battery pack is greater than the second voltage, the battery pack can also step down the voltage through the second circuit to charge C11 or the negative capacitor C12 connected to the second circuit.

[0112] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0113] The following is an embodiment of the load power supply device of the present application. For details not described in detail, reference may be made to the above-mentioned corresponding embodiment of the battery bidirectional circuit.

[0114] Figure 2 The structural diagram of the load power supply device provided in the embodiment of the present application is shown. For the convenience of explanation, only the part related to the embodiment of the present application is shown, which is described in detail as follows:

[0115] like Figure 2As shown, the load power supply device includes: an electric energy input module, a DC bus, a conversion circuit, a battery pack and a battery bidirectional circuit as in any of the above embodiments.

[0116] The DC bus is connected to the power input module, and the DC bus is connected to the load through a conversion circuit; wherein the DC bus includes a positive bus +BUS, a negative bus -BUS and a neutral line N;

[0117] The battery bidirectional circuit is connected to the battery pack through the first port D01 and the second port D02 on the battery side, and is connected to the positive bus +BUS and the negative bus -BUS through the third port D03 and the fourth port D04 on the bus side, and the fifth port is connected to the neutral line N.

[0118] In this embodiment, external input electric energy can be connected to the DC bus through the electric energy input module, the battery pack can be connected to the DC bus through the battery bidirectional circuit, and the DC bus can be connected to the load through the conversion circuit, thereby supplying power to the load.

[0119] In the non-battery power supply mode, the external input power can be provided as a DC bus through the power input module to enable the load to work normally. At the same time, the battery pack can also be charged through the battery bidirectional circuit.

[0120] In battery-powered mode, the battery pack supplies power to the DC bus through the battery bidirectional circuit to ensure uninterrupted power supply to the load.

[0121] In some embodiments, the load power supply device further includes a controller. Figure 5 As shown, the power input module includes a rectifier circuit, and the input end of the rectifier circuit is used to connect to the mains input; in this case, the load power supply device is an uninterruptible power supply. The controller is used to:

[0122] When the AC power input from the mains is normal, the mains power supply mode is entered. The AC power input from the mains supplies power to the DC bus through the rectifier circuit, is supplied to the load through the conversion circuit, and also charges the battery pack through the battery bidirectional circuit.

[0123] When the AC power input from the mains fails, the system enters the battery power supply mode. The battery pack supplies power to the DC bus through the battery bidirectional circuit and provides it to the load through the conversion circuit.

[0124] Here, in the uninterruptible power supply, a first switch K1 and a second switch K2 may be provided, the mains input is connected to the rectifier circuit through the first switch K1, and the battery pack is connected to the battery bidirectional circuit through the second switch K2.

[0125] When the first switch K1 is turned on and the second switch K2 is turned on, it is in the mains power supply mode. When the first switch K1 is turned off and the second switch K2 is turned on, it is in the battery power supply mode.

[0126] Here, the controller may be physically multiple controllers, which respectively control different circuits in the uninterruptible power supply. For example, the uninterruptible power supply may include a first controller and a second controller, the first controller is used to control the rectifier circuit and the battery bidirectional circuit, and the second controller is used to control the conversion circuit. Accordingly, the first controller may also control the first switch K1 and the second switch K2. Specifically, one controller may be a control chip.

[0127] Optionally, the rectifier circuit may adopt a power factor correction (PFC) boost circuit. In this embodiment, two PFC boost circuits are used for exemplary description.

[0128] See also Figure 5 The circuit structure diagram of the first single-phase uninterruptible power supply shown in the figure, the PFC boost circuit includes a third inductor L3, a first diode D1, a second diode D2, a fifth switch tube Q5 and a sixth switch tube Q6; the first end of the third inductor L3 serves as the input end of the PFC boost circuit; the second end of the third inductor L3 is respectively connected to the anode of the first diode D1, the cathode of the second diode D2 and the collector of the fifth switch tube; the cathode of the first diode D1 is used to connect to the positive bus +BUS; the anode of the second diode D2 is used to connect to the negative bus -BUS; the emitter of the fifth switch tube Q5 is connected to the emitter of the sixth switch tube, and the collector of the sixth switch tube Q6 is used to connect to the neutral line N.

[0129] Here, if Figure 8 As shown, the PFC boost circuit may further include a first current transformer CT1, a first end of the first current transformer CT1 serves as an input end of the PFC boost circuit, and a second end of the first current transformer CT1 is connected to a first end of the second inductor L2.

[0130] When the mains input is three-phase AC, refer to Fig.11 The circuit structure diagram of the first three-phase uninterruptible power supply shown in the figure comprises three first switches K1 and three PFC boost circuits, and each phase of the three-phase alternating current corresponds to a first switch K1 and a PFC boost circuit; for each phase, the first end of the corresponding first switch K1 is used to connect the alternating current of the phase, and the second end of the corresponding first switch K1 is connected to the input end of the PFC boost circuit of the phase.

[0131] See also Fig.12 In the circuit structure diagram of the third single-phase uninterruptible power supply shown in FIG. 1 , the first switch K1 includes a first thyristor SCR1 and a second thyristor SCR2 , and the PFC boost circuit includes a third inductor L3 , a first diode D1 , a second diode D2 , a fifth switch tube Q5 and a sixth switch tube Q6 .

[0132] The anode of the first thyristor SCR1 is connected to the cathode of the second thyristor SCR2 and serves as the first end of the first switch K1; the cathode of the first thyristor SCR1 serves as the first port of the second end of the first switch K1 and is connected to the first end of the third inductor L3; the anode of the second thyristor SCR2 serves as the second port of the second end of the first switch K1 and is connected to the first end of the fourth inductor L4.

[0133] Here, when the gate of the first thyristor SCR1 is subjected to a forward voltage, when the anode potential of the first thyristor SCR1 is higher than the cathode potential, the first thyristor SCR1 is turned on and can transmit current; when the cathode potential of the first thyristor SCR1 is higher than the anode potential, the first thyristor SCR1 is reversely blocked and cannot transmit current. That is, when the AC power input from the mains is a positive half-wave, it can be input into the PFC boost circuit through the first thyristor SCR1.

[0134] Correspondingly, when the gate of the second thyristor SCR2 is subjected to a forward voltage, when the anode potential of the second thyristor SCR2 is higher than the cathode potential, the second thyristor SCR2 is turned on and can transmit current; when the cathode potential of the second thyristor SCR2 is higher than the anode potential, the second thyristor SCR2 is reversely blocked and cannot transmit current. That is, when the AC input of the mains is a negative half-wave, the second thyristor SCR2 is turned on, and the PFC boost circuit is connected to the mains input.

[0135] In this PFC boost circuit, the second end of the third inductor L3 is respectively connected to the anode of the first diode D1 and the collector of the fifth switch tube Q5; the cathode of the first diode D1 is connected to the positive bus +BUS; the emitter of the fifth switch tube Q5 is used to connect to the neutral line N; the second end of the fourth inductor L4 is respectively connected to the emitter of the sixth switch tube Q6 and the cathode of the second diode D2; the anode of the second diode D2 is connected to the negative bus -BUS; the collector of the sixth switch tube Q6 is used to connect to the neutral line N.

[0136] Here, the PFC boost circuit also includes a first current transformer CT1 and a second current transformer CT2, the first end of the first current transformer CT1 serves as an input end of the PFC boost circuit, and the second end of the first current transformer CT1 is connected to the first end of the third inductor L3; the first end of the second current transformer CT2 serves as an input end of the PFC boost circuit, and the second end of the second current transformer CT2 is connected to the first end of the fourth inductor L4.

[0137] In addition, if Fig.12 As shown, the second switch K2 may include a first relay RLY1, a second relay RLY2 and a first resistor R1; after the second relay RLY2 is connected in series with the first resistor R1, it is connected in parallel with the first relay RLY1, which can reduce the starting current and loss.

[0138] When the mains input is three-phase AC, refer to Fig.13 The circuit structure diagram of the second three-phase uninterruptible power supply is shown, and the uninterruptible power supply includes three first switches K1, and each phase of the three-phase alternating current corresponds to a first switch K1; for each phase, the first end of the corresponding first switch K1 is used to connect the alternating current of the phase, the first port of the corresponding first switch K1 is connected to the first end of the third inductor L3, and the second port of the second end of the corresponding first switch K1 is connected to the first end of the fourth inductor L4.

[0139] In this embodiment, in the mains power supply mode, each phase of AC power is input into the PFC boost circuit through the corresponding first switch K1 , and the PFC boost circuit converts the received three-phase AC power into DC power and inputs it into the DC bus.

[0140] Here, by setting three first switches K1, the three-phase AC power can be input into one PFC boost circuit, without setting three PFC boost circuits, which can reduce the components of the PFC boost circuit, reduce the circuit volume, and reduce the cost.

[0141] The above embodiments introduce the specific structures of two PFC boost circuits. The specific structure of the conversion circuit will be further introduced below.

[0142] The conversion circuit can be a direct current (DC)-to-DC conversion circuit or an inverter circuit. When the current required by the load is direct current, a DC-DC conversion circuit can be used to convert direct current and then provide it to the load; when the current required by the load is alternating current, an inverter circuit can be used to convert direct current into alternating current and then provide it to the load.

[0143] When the conversion circuit is an inverter circuit, the electric energy stored in the positive capacitor C11 and the negative capacitor C12 can be converted into alternating current. Specifically, the inverter circuit converts the electric energy stored in the positive capacitor C11 into the positive half-wave of the output alternating current, and the inverter circuit converts the electric energy stored in the negative capacitor C12 into the negative half-wave of the output alternating current.

[0144] like Figure 5 As shown, the inverter circuit may adopt an I-type inverter circuit. The inverter circuit includes a third diode D3, a fourth diode D4, a first inverter switch tube Q71, a second inverter switch tube Q72, a third inverter switch tube Q73 and a fourth inverter switch tube Q74.

[0145] The anode of the third diode D3 is connected to the neutral line N, and the cathode of the third diode D3 is connected to the emitter of the first inverter switch tube Q71 and the collector of the second inverter switch tube Q72; the collector of the first inverter switch tube Q71 is connected to the positive bus +BUS, and the emitter of the second inverter switch tube Q72 serves as the output end of the inverter circuit.

[0146] The cathode of the fourth diode D4 is connected to the neutral line N, and the anode of the fourth diode D4 is connected to the emitter of the third inverter switch tube Q73 and the collector of the fourth inverter switch tube Q74; the collector of the third inverter switch tube Q73 serves as the output end of the inverter circuit, and the emitter of the fourth inverter switch tube Q74 is connected to the negative bus -BUS.

[0147] In addition, the output end of the inverter circuit can be connected to a load via a fifth inductor L5.

[0148] Two current transformers may also be connected between the fifth inductor L5 and the load, such as Fig.11 The fourth current transformer CT4 and the fifth current transformer CT5.

[0149] In addition, a fourth capacitor C4 may be connected between the live wire and the neutral wire of the output AC power to filter out high-frequency signals in the output AC power and prevent high-frequency interference from leaking from the output AC power and interfering with the load.

[0150] Optional, such as Fig.14 The circuit structure diagram of the fourth single-phase uninterruptible power supply is shown. A common mode inductor can also be set in the uninterruptible power supply. The uninterruptible power supply also includes a first common mode inductor Lc1, a second common mode inductor Lc2 and a third common mode inductor Lc3. The AC power input from the mains is connected to the rectifier circuit through the first common mode inductor Lc1; the battery pack is connected to the battery bidirectional circuit through the second common mode inductor Lc2; and the conversion circuit supplies power to the load through the third common mode inductor Lc3.

[0151] See also Figure 11-Figure 14 The uninterruptible power supply also includes a bypass and a third switch K3; the input end of the bypass is used to connect to the mains input, and the output end of the bypass is connected to the first end of the third switch K3; the second end of the third switch K3 is connected to the output end of the conversion circuit, and the third end of the third switch K3 is used to connect to the load.

[0152] By controlling the third switch K3, when bypass operation is required, the first end of the third switch K3 can be controlled to be turned on to turn on the bypass, and the AC power input from the mains can be directly provided to the load through the bypass; when the UPS is used normally, the second end of the third switch K3 can be controlled to be turned on to turn off the bypass.

[0153] In some other embodiments, the load power supply device further includes a controller, see Fig.15As shown in the structural schematic diagram of the first photovoltaic power generation system, the power input module includes a direct current-direct current (DC-DC) converter; the input end of the DC-DC converter is used to connect the photovoltaic power generation input; at this time, the load power supply device is the photovoltaic power generation system.

[0154] The controller is used to: enter the photovoltaic power generation mode when the direct current power input by the photovoltaic power generation is normal; enter the battery power supply mode when the direct current power input by the photovoltaic power generation fails.

[0155] In this embodiment, the photovoltaic power generation input can be solar radiation energy converted into electrical energy through the photovoltaic array and direct current that is combined through the photovoltaic combiner box. In the non-battery power supply mode, that is, the photovoltaic power generation mode, the direct current input from the photovoltaic power generation is rectified and converted through the DC-DC converter and provided to the DC bus, and then the load is powered through the conversion circuit. At the same time, the battery pack can also be charged through the battery bidirectional circuit.

[0156] When the DC power input by photovoltaic power generation fails, that is, when there is insufficient sunlight, the photovoltaic array converts insufficient electrical energy and cannot meet the load. It can enter the battery power supply mode. The battery pack supplies power to the DC bus through the battery bidirectional circuit, thereby ensuring the normal operation of the load.

[0157] Here, the controller can also be physically multiple controllers, which respectively control different circuits in the photovoltaic power generation system. For example, the photovoltaic power generation system may include a third controller and a fourth controller, the third controller is used to control the DC-DC converter and the battery bidirectional circuit, and the fourth controller is used to control the conversion circuit. Specifically, one controller can be a control chip.

[0158] In addition, the conversion circuit in the photovoltaic power generation system can be a photovoltaic grid-connected inverter, through which the electricity generated by the photovoltaic array can be connected to the power grid. Fig.15 The load in the grid can be replaced by the grid.

[0159] In this embodiment, in the photovoltaic power generation mode, the direct current input by the photovoltaic power generation is rectified and converted by the DC-DC converter and then input into the battery pack, and then provided to the DC bus through the battery bidirectional circuit to supply power to the load. Among them, by setting up the battery pack, fluctuations can be suppressed to ensure the smooth operation of the load.

[0160] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0161] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A battery bidirectional circuit, characterized in that: A load power supply device applied to a battery pack and a DC bus; the DC bus includes a positive bus, a negative bus and a neutral line; the battery bidirectional circuit includes a first circuit and a second circuit; the first circuit includes a first inductor, a first switch tube and a second switch tube; the second circuit includes a second inductor, a third switch tube and a fourth switch tube; The first end of the first inductor and the first end of the third switch tube serve as a first port of the battery bidirectional circuit; A connection point between the second end of the first inductor and the first end of the second switch tube is connected to a connection point between the second end of the third switch tube and the first end of the fourth switch tube through the first switch tube and the second inductor; The connection point between the first switch tube and the second inductor serves as the second port and the fifth port of the battery bidirectional circuit; the second end of the second switch tube serves as the third port of the battery bidirectional circuit, and the second end of the fourth switch tube serves as the fourth port of the battery bidirectional circuit; The first port and the second port are used to connect a battery pack, the third port and the fourth port are used to connect a positive bus bar and a negative bus bar, and the fifth port is used to connect a neutral line.

2. The battery bidirectional circuit according to claim 1, characterized in that: When the first port is used to connect the positive electrode of the battery pack and the second port is used to connect the negative electrode of the battery pack, the third port is connected to the positive bus bar and the fourth port is connected to the negative bus bar; When the first port is used to connect the negative electrode of the battery pack and the second port is used to connect the positive electrode of the battery pack, the third port is connected to the negative bus bar and the fourth port is connected to the positive bus bar.

3. The battery bidirectional circuit according to claim 1, characterized in that: A positive capacitor is connected between the positive busbar and the neutral line, and a negative capacitor is connected between the neutral line and the negative busbar; When the load power supply device is in a non-battery power supply mode, when there is a voltage difference between the positive capacitor and the negative capacitor, the capacitor with a higher voltage between the positive capacitor and the negative capacitor charges the battery pack; or, the positive capacitor and the negative capacitor charge the battery pack; In which, in a charging cycle, the first charging energy is greater than the second charging energy, the first charging energy is the energy used by the capacitor with a higher voltage between the positive capacitor and the negative capacitor to charge the battery pack, and the second charging energy is the energy used by the capacitor with a lower voltage between the positive capacitor and the negative capacitor to charge the battery pack.

4. The battery bidirectional circuit according to claim 3, characterized in that: In the non-battery power supply mode, when there is a voltage difference between the positive capacitor and the negative capacitor, the load power supply device controls the two switch tubes of the circuit connected to the capacitor with a higher voltage in the battery bidirectional circuit to be alternately turned on, and controls the main switch tube of the circuit connected to the capacitor with a lower voltage in the battery bidirectional circuit to be turned off, so that the capacitor with a higher voltage among the positive capacitor and the negative capacitor charges the battery pack; wherein the main switch tube of the first circuit is the second switch tube, and the main switch tube of the second circuit is the fourth switch tube.

5. The battery bidirectional circuit according to claim 3, characterized in that: In the non-battery power supply mode, when there is a voltage difference between the positive capacitor and the negative capacitor, the load power supply device controls the first switch tube and the second switch tube to be alternately turned on, and controls the third switch tube and the fourth switch tube to be alternately turned on, so that the positive capacitor and the negative capacitor charge the battery pack; wherein, in a charging cycle, the first charging energy is greater than the second charging energy.

6. The battery bidirectional circuit according to any one of claims 3 to 5, characterized in that: In the non-battery power supply mode, when the positive capacitor and the negative capacitor are balanced, the load power supply device controls the first switch tube and the second switch tube to be alternately turned on, and controls the third switch tube and the fourth switch tube to be alternately turned on, so that the positive capacitor and the negative capacitor charge the battery pack; wherein, in one charging cycle, the energy charged by the positive capacitor and the negative capacitor for the battery pack is equal; In the battery power supply mode, the load power supply device controls the first switch tube and the second switch tube to be alternately turned on, and controls the third switch tube and the fourth switch tube to be alternately turned on, so that the battery pack charges the positive capacitor and the negative capacitor; wherein, in a charging cycle, the energy charged by the battery pack for the positive capacitor and the negative capacitor is equal.

7. The battery bidirectional circuit according to claim 1, characterized in that: A positive capacitor is connected between the positive busbar and the neutral line, and a negative capacitor is connected between the neutral line and the negative busbar; The voltage of the battery pack is greater than a second voltage of the positive capacitor or the negative capacitor connected to the second circuit; When the load power supply device is in a non-battery power supply mode, when the second voltage is greater than the first voltage of the positive capacitor or the negative capacitor connected to the first circuit, or when the power of the load is less than a preset power, the positive capacitor or the negative capacitor connected to the second circuit is boosted by the second circuit to charge the battery pack; When the load power supply device is in the battery power supply mode, the battery pack charges the positive capacitor or the negative capacitor connected to the second line by reducing the voltage of the second line.

8. A load power supply device, characterized in that: It comprises an electric energy input module, a DC bus, a conversion circuit, a battery pack and a battery bidirectional circuit as described in any one of claims 1 to 7 above; The DC bus is connected to the power input module, and the DC bus is connected to the load through the conversion circuit; wherein the DC bus includes a positive bus, a negative bus and a neutral line; The battery bidirectional circuit is connected to the battery pack through the first port and the second port on the battery side, and is connected to the positive bus and the negative bus through the third port and the fourth port on the bus side, and the fifth port is connected to the neutral line.

9. The load power supply device according to claim 8, characterized in that: The load power supply device also includes a controller; the power input module includes a rectifier circuit; the input end of the rectifier circuit is used to connect to the mains input; The controller is used to: When the AC power input from the mains is normal, entering the mains power supply mode; When the AC power input from the mains fails, the system enters the battery power supply mode.

10. The load power supply device according to claim 8, characterized in that: The load power supply device also includes a controller; the power input module includes a DC-DC converter; the input end of the DC-DC converter is used to connect to the photovoltaic power generation input; The controller is used to: When the DC power input by photovoltaic power generation is normal, it enters photovoltaic power generation mode; When the DC power input from photovoltaic power generation fails, the system enters battery power supply mode.

Images