Photovoltaic-cell power supply device and system

Abstract

The invention provides a photovoltaic-battery power supply device and system, and relates to the field of power supplies, batteries for energy storage are divided into a plurality of groups, when the batteries are charged through a diode group, the batteries with low voltage are firstly charged, and when the batteries are discharged through the diode group connected with a main DC / DC converter, the batteries with high voltage are firstly discharged. Voltage balance can be automatically realized among a plurality of battery packs, the system loss is reduced, the efficiency of the system is improved, and the standby time of the system is prolonged; the auxiliary DC / DC converter serves as an auxiliary power supply of all the maximum power point tracking circuits, and the auxiliary DC / DC converter works to supply power to the maximum power point tracking circuits when illumination exists, so that the static loss of the system is reduced, the light load efficiency of the system is improved, and the standby time of the system is prolonged.

Description

Technical Field

[0001] The present application relates to the field of power supply, in particular to photovoltaic-battery power supply devices and systems. Background Art

[0002] Photovoltaic-battery power supply systems are widely used in long-term power supply of outdoor equipment, such as outdoor hydrological monitoring systems, outdoor video surveillance systems, etc.

[0003] Typically, when there is sunlight, photovoltaic panels generate electricity to power the load and store the electricity in a battery pack; when there is no sunlight, the electricity stored in the battery pack is used to power the load.

[0004] It can be seen that the advantage of using a photovoltaic-battery power supply system is that it does not require mains electricity facilities and is flexible and convenient to install. The disadvantage is that due to the instability of light, in order to ensure that the equipment can work without power outages for a long time, the system needs to be designed according to the worst case, which usually requires multiple photovoltaic panels and multiple battery packs to be flexibly configured. However, this will lead to problems such as increased standby power consumption and reduced light-load efficiency of the system, and the reliability of the current system cannot meet the needs. Summary of the invention

[0005] The present application provides a photovoltaic-battery power supply device, comprising:

[0006] The maximum power point tracking circuit has an input end connected to a photovoltaic panel and an output end connected to a DC bus;

[0007] A first diode group, comprising a plurality of diodes, anodes of which are all connected to the DC bus, and cathodes of which are used to be connected to the battery groups one by one;

[0008] A second diode group, comprising a plurality of diodes, anodes of which are connected one-to-one with cathodes of the diodes in the first diode group, and cathodes of which are connected to each other to form an output end of the second diode group;

[0009] A main DC / DC converter, having an input end connected to the output end of the second diode group and an output end for connecting to a load;

[0010] A selection unit, wherein the first input end is used to connect to the photovoltaic panel, and the second output end is connected to the output end of the second diode group;

[0011] An auxiliary DC / DC converter, whose input end is connected to the output end of the selection unit, and whose output end is used to connect to a load and a power supply end of the maximum power point tracking circuit;

[0012] A mode control unit receives the output voltage of the photovoltaic panel and the output voltage of the main DC / DC converter, and is used to output a control signal for controlling whether the auxiliary DC / DC converter works according to the output voltage of the photovoltaic panel and the output voltage of the main DC / DC converter.

[0013] Furthermore, the selection unit is configured to select the output voltage of the second diode group or the output voltage of the photovoltaic panel as the input of the auxiliary DC / DC converter.

[0014] Furthermore, the selection unit includes a first diode and a second diode, the anode of the first diode is connected to the photovoltaic panel, the anode of the second diode is connected to the output end of the second diode group, and the cathode of the first diode and the cathode of the second diode are connected to the input end of the auxiliary DC / DC converter.

[0015] Furthermore, the mode control unit is configured as follows:

[0016] When the output voltage of the photovoltaic panel is high, the control signal output by the mode control unit enables the auxiliary DC / DC converter to operate;

[0017] When the output voltage of the photovoltaic panel is low and the output voltage of the main DC / DC converter is high, the control signal output by the mode control unit causes the auxiliary DC / DC converter to not work;

[0018] When the output voltage of the photovoltaic panel is low and the output voltage of the main DC / DC converter is low, the control signal output by the mode control unit enables the auxiliary DC / DC converter to operate.

[0019] Furthermore, the control signal output by the mode control unit is used to control the control chip of the auxiliary DC / DC converter. When the control signal is at a high level, the control chip works to output a switch control signal for controlling the operation of the auxiliary DC / DC converter. When the control signal is at a low level, the control chip does not work.

[0020] Furthermore, the mode control unit is implemented by a digital circuit.

[0021] Furthermore, the mode control unit includes:

[0022] A first control unit, an input end of which receives the output voltage of the photovoltaic panel;

[0023] A second control unit, an input end of which receives the output voltage of the main DC / DC converter and is connected to the output end of the first control unit, wherein when the output voltage of the photovoltaic panel is at a high level, the output end of the first control unit pulls down the input end of the second control unit, so that the second control unit outputs a high level; when the output voltage of the photovoltaic panel is at a low level, the output end of the first control unit is at a high level, and if the output voltage of the main DC / DC converter is at a low level at this time, the output of the second control unit is high, and if the output voltage of the main DC / DC converter is also at a high level at this time, the output of the second control unit is pulled down.

[0024] Furthermore, the first control unit includes a first control switch tube, a control end of the first control switch tube forms an input end of the first control unit, a second end of the first control switch tube is grounded, and a first end of the first control switch tube forms an output end of the first control unit;

[0025] The second control unit includes a second control switch tube, a control end of the second control switch tube forms an input end of the second control unit, a second end of the second control switch tube is grounded, and a first end of the second control switch tube forms an output end of the mode control unit.

[0026] Furthermore, there are multiple maximum power point tracking circuits, the input ends of the maximum power point tracking circuits are used to be connected to the photovoltaic panels in a one-to-one correspondence, and the output ends are connected to the DC bus;

[0027] The output end of the auxiliary DC / DC converter is connected to the power supply end of all maximum power point tracking circuits;

[0028] The selection unit includes a plurality of first diodes, and anodes of the plurality of first diodes are connected to the photovoltaic panels in a one-to-one correspondence;

[0029] The mode control unit receives the output voltages of all photovoltaic panels.

[0030] Furthermore, the mode control unit also includes a third control unit, and the third control unit includes a plurality of diodes, anodes of which are connected to the photovoltaic panels one by one, and cathodes of which are connected to the input end of the first control unit.

[0031] Furthermore, the output end of the main DC / DC converter is used to connect to the load through a first switch tube; the output end of the auxiliary DC / DC converter is used to connect to the load through a second switch tube.

[0032] Furthermore, the first switch tube is a MOSFET; and the second switch tube is a diode.

[0033] The present application also provides a photovoltaic-battery power supply system, comprising:

[0034] The photovoltaic-battery powered device described above;

[0035] Photovoltaic panels connected one-to-one with the maximum power point tracking circuit in the photovoltaic-battery power supply device;

[0036] A battery group connected in a one-to-one correspondence with the cathodes of the diodes in the first diode group in the photovoltaic-battery powered device;

[0037] A load is connected to the output end of the main DC / DC converter and the output end of the auxiliary DC / DC converter.

[0038] The features and technical advantages of the present disclosure have been summarized quite extensively above so that the detailed description disclosed below may be better understood. Additional features and advantages of the present disclosure will be described below, which constitute the subject matter of the claims of the present disclosure. It will be appreciated by those skilled in the art that the disclosed concepts and specific embodiments may be easily used as a basis for modifying or designing other structures or processes for achieving the same purpose of the present disclosure. It will also be appreciated by those skilled in the art that such equivalent structures do not depart from the spirit and scope of the present disclosure as set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, in which:

[0040] Figure 1 A schematic diagram of a photovoltaic-battery power supply system according to an embodiment of the present application is shown;

[0041] Figure 2 A schematic diagram of a photovoltaic-battery power supply system according to another embodiment of the present application is shown;

[0042] Figure 3 Shows Figure 1 A schematic diagram of a mode control unit in FIG.

[0043] Figure 4 Shows Figure 2 Schematic diagram of the mode control unit in FIG.

[0044] Unless otherwise indicated, corresponding parts and symbols in the different figures generally refer to corresponding parts. These figures are drawn to clearly illustrate the relevant aspects of the various embodiments and are not necessarily drawn to scale. DETAILED DESCRIPTION

[0045] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] One embodiment of the present application is to provide a photovoltaic-battery power supply device. Figure 1 The schematic diagram of a photovoltaic-battery power supply system of an embodiment of the present application is shown, wherein the photovoltaic-battery power supply device 10 includes:

[0047] The maximum power point tracking circuit 100 has an input end connected to the photovoltaic panel 20 and an output end connected to the DC bus BUS;

[0048] A first diode group 210, comprising a plurality of diodes, anodes of which are all connected to the DC bus BUS, and cathodes of which are used to be connected to the battery packs one by one;

[0049] A second diode group 220 includes a plurality of diodes, wherein the anodes are connected to the cathodes of the diodes in the first diode group 210 in a one-to-one correspondence, and the cathodes are connected to each other to form an output end of the second diode group 220;

[0050] A main DC / DC converter 320, an input end of which is connected to the output end of the second diode group 220, and an output end of which is used to connect to a load 40;

[0051] A selection unit 230, a first input end is used to connect to the photovoltaic panel 20, and a second output end is connected to the output end of the second diode group 220;

[0052] An auxiliary DC / DC converter 310, whose input end is connected to the output end of the selection unit 230, and whose output end is used to connect to the load 40 and the power supply end of the maximum power point tracking circuit 100;

[0053] The mode control unit 400 receives the output voltage PVW of the photovoltaic panel 20 and the output voltage Vmo of the main DC / DC converter 320, and is used to output a control signal CS for controlling whether the auxiliary DC / DC converter works according to the output voltage PVW of the photovoltaic panel 20 and the output voltage Vmo of the main DC / DC converter 320.

[0054] like Figure 1 As shown, a photovoltaic panel 20 and a corresponding maximum power point tracking circuit 100 are used to implement maximum power point tracking. In practical applications, multiple photovoltaic panels and corresponding maximum power point tracking circuits can also be configured. Figure 2The schematic diagram of the photovoltaic-battery power supply system of another embodiment of the present application is shown, which is equipped with photovoltaic panels 21 to photovoltaic panels 2n, and correspondingly includes maximum power point tracking circuits 100 to maximum power point tracking circuits 10n, and the input ends of the maximum power point tracking circuits 100 to maximum power point tracking circuits 10n are used to be connected to the photovoltaic panels 21 to photovoltaic panels 2n one by one, and the output ends are connected to the DC bus BUS. Figure 2 As shown, the input end of the maximum power point tracking circuit 100 is used to connect to the photovoltaic panel 21, and the input end of the maximum power point tracking circuit 10n is used to connect to the photovoltaic panel 2n, where n is a natural number. And the output end of the auxiliary DC / DC converter 310 is connected to the power supply end of all the maximum power point tracking circuits (maximum power point tracking circuit 101 to maximum power point tracking circuit 10n).

[0055] like Figure 1 As shown, there are multiple battery packs for energy storage, such as battery pack 31 to battery pack 3n, and each battery pack is connected to the DC bus BUS through a diode, such as battery pack 31 is connected to the DC bus BUS through diode D11, and battery pack 3n is connected to the DC bus BUS through diode D1n. In this way, when there is light to store energy for the battery pack, the diode connected to the battery pack with low voltage is turned on first, that is, the battery pack with low voltage is charged first, so that voltage balance is automatically achieved among multiple battery packs, and the loss caused by internal circulation caused by voltage imbalance between battery packs is avoided, which can not only improve the life of the battery pack, but also reduce the loss and increase the standby time of the system. Furthermore, the complex sampling, calculation and control circuits required for achieving voltage balance between battery packs in the prior art are also omitted, the volume of the entire system is reduced, and the static loss and working loss caused by these circuits are also avoided, further improving the efficiency and standby time of the system, where n is a natural number.

[0056] like Figure 1 As shown, the anodes of the diodes in the second diode group 220 are connected to the cathodes of the diodes in the first diode group 210 (i.e., used to connect to the battery packs) in a one-to-one correspondence, such as the anode of the diode D21 is connected to the cathode of the diode D11 (i.e., used to connect to the first battery pack 31), and the anode of the diode D2n is connected to the cathode of the diode D1n (i.e., used to connect to the nth battery pack 3n). In this way, when the battery pack is discharged, the diodes in the second diode group 220 connected to the battery pack with a high voltage are turned on first, that is, the battery pack with a high voltage is discharged first, which also automatically achieves voltage balancing between multiple battery packs. Its advantages are the same as the advantages of automatically achieving voltage balancing when charging the battery pack, which will not be repeated here.

[0057] It can be seen that the present application adopts multiple battery packs in parallel, and adopts a diode to isolate the charging path during the charging process to ensure that the battery pack with low voltage is charged first; the discharge process adopts an independent diode to isolate the discharge channel to ensure that the battery pack with high voltage is discharged first, thereby reducing the circulation current between the battery packs.

[0058] like Figure 1 As shown, the auxiliary DC / DC converter 310 supplies power to the maximum power point tracking circuit 100, and the output end thereof and the output end of the main DC / DC converter 320 are both connected to the load 40. First, the auxiliary DC / DC converter 310 and the main DC / DC converter 320 form a mutual backup for supplying power to the load 40, which improves the reliability of supplying power to the load 40. Second, the output voltage Vfo of the auxiliary DC / DC converter 310 supplies power to the maximum power point tracking circuit 100, eliminating the auxiliary power supply dedicated to supplying power to the maximum power point tracking circuit 100, further reducing the volume of the entire system, reducing losses, and improving the efficiency and standby time of the system.

[0059] See also Figure 2 The output end of the auxiliary DC / DC converter 310 is connected to the power supply end of all the maximum power point tracking circuits (maximum power point tracking circuit 101 to maximum power point tracking circuit 10n). That is, all the maximum power point tracking circuits are powered by a unified power supply. Compared with the solution of each maximum power point tracking circuit in the prior art using an auxiliary power supply, when there are multiple groups of photovoltaic panels, the volume of the entire system is greatly reduced, the static loss of the auxiliary power supply is also reduced, and the light load efficiency and standby time of the system are improved.

[0060] Specifically, in one embodiment, the mode control unit 400 is configured as follows: when the output voltage PVW of the photovoltaic panel is high (there is light), the control signal CS output by the mode control unit 400 enables the auxiliary DC / DC converter 310 to operate; when the output voltage PVW of the photovoltaic panel is low (there is no light) and the output voltage Vmo of the main DC / DC converter 320 is high, the control signal CS output by the mode control unit 400 enables the auxiliary DC / DC converter 310 not to operate; when the output voltage PVW of the photovoltaic panel is low (there is no light) and the output voltage Vmo of the main DC / DC converter 320 is low, the control signal CS output by the mode control unit 400 enables the auxiliary DC / DC converter 310 to operate.

[0061] It can be seen that when the photovoltaic panel has no power output, that is, when there is no light, if the main DC / DC converter 320 can work normally, that is, it can convert the electric energy provided by the battery pack into electric energy for powering the load, then the auxiliary DC / DC converter 310 will not work, and the maximum power point tracking circuit 100 will also not work, which reduces the static loss of the maximum power point tracking circuit 100 and the auxiliary DC / DC converter 310.

[0062] Furthermore, when the photovoltaic panel has no power output, that is, when there is no light, if the main DC / DC converter 320 cannot work normally, the auxiliary DC / DC converter 310 works as a backup to supply power to the load, which ensures the reliability of power supply to the load.

[0063] It can be seen that when the photovoltaic panel has power output, that is, when there is light, the auxiliary DC / DC converter 310 works to supply power to the maximum power point tracking circuit 100, and the maximum power point tracking circuit 100 performs maximum power point tracking on the electric energy provided by the photovoltaic panel to store the most energy in the battery pack.

[0064] That is, the auxiliary DC / DC converter 310 works only when the photovoltaic panel has power output or the main DC / DC converter 320 cannot work normally, which not only reduces the static loss caused by the auxiliary DC / DC converter 310 and the maximum power point tracking circuit 100, but also improves the reliability of power supply to the load.

[0065] Furthermore, in one embodiment, when the output voltage of the photovoltaic panel is high, if the main DC / DC converter 320 can work normally, the higher of the output voltage Vmo of the main DC / DC converter 320 and the output voltage Vfo of the auxiliary DC / DC converter 310 supplies power to the load 40; if the main DC / DC converter 320 cannot work normally, only the auxiliary DC / DC converter 310 supplies power to the load 40.

[0066] In a specific embodiment, the control signal CS output by the mode control unit 400 is used to control the control chip of the auxiliary DC / DC converter 310. When the control signal CS is at a high level, the control chip works to output a switch control signal for controlling the operation of the auxiliary DC / DC converter 310. When the control signal CS is at a low level, the control chip does not work, and the corresponding auxiliary DC / DC converter 310 does not work either.

[0067] In practical applications, in a specific embodiment, the mode control unit 400 is implemented by a digital circuit, and may also be implemented by an analog circuit.

[0068] When it is implemented by an analog circuit, in a specific embodiment, please refer to Figure 3The schematic diagram of the mode control unit shown in Figure 1 The mode control unit 400 includes: a first control unit 420, whose input end receives the output voltage PVW of the photovoltaic panel 20; a second control unit 430, whose input end receives the output voltage Vmo of the main DC / DC converter 320 and is connected to the output end of the first control unit 420, wherein when the output voltage PVW of the photovoltaic panel 20 is at a high level (there is light), the output end of the first control unit 420 pulls down the input end of the second control unit 430, so that the output signal CS of the second control unit 430 is at a high level, and the control chip 311 in the auxiliary DC / DC converter 310 works and outputs the switch control signal PWM for controlling its work, so that when there is light, the auxiliary DC / DC converter 310 works and the maximum power point tracking circuit 100 also works. When the output voltage PVW of the photovoltaic panel 20 is low (no light), the output terminal of the first control unit 420 is high. If the output voltage Vmo of the main DC / DC converter 320 is low (the main DC / DC converter 320 cannot work normally), the output signal CS of the second control unit 430 is high, and the control chip 311 in the auxiliary DC / DC converter 310 outputs the switch control signal PWM for controlling its operation, so that the auxiliary DC / DC converter 310 works to supply power to the load. If the output voltage Vmo of the DC / DC converter 320 is also high, the output signal CS of the second control unit 430 is pulled low, the control chip 311 does not work, and the auxiliary DC / DC converter 310 does not work. At this time, the main DC / DC converter 320 works to supply power to the load. Compared with the prior art where the auxiliary power supply is always working, the system loss can be reduced.

[0069] In one specific embodiment, see Figure 3 The first control unit 420 includes a first control switch tube Q1, a control end of the first control switch tube Q1 forms an input end of the first control unit 420, a second end of the first control switch tube Q1 is grounded GND, and a first end of the first control switch tube Q1 forms an output end of the first control unit 420. In this way, when the output voltage PV1W of the photovoltaic panel 20 is high, the first control switch tube Q1 is turned on, and the output end of the first control unit 420 is pulled low, and when the output voltage PV1W of the photovoltaic panel 20 is low, the first control switch tube Q1 is turned off, and the first control unit 420 is high.

[0070] The second control unit 430 includes a second control switch tube Q2, the control end of the second control switch tube Q2 forms the input end of the second control unit 430, the second end of the second control switch tube Q2 is grounded GND, and the first end of the second control switch tube Q2 forms the output end of the mode control unit 400. In this way, when the output of the first control unit 420 is high and the output of the main DC / DC converter 320 is also high, the second control switch tube Q2 is turned on, and the output of the mode control unit 400 is pulled low; when the output of the first control unit 420 is high and the output of the main DC / DC converter 320 is low, the second control switch tube Q2 is turned off, and the output of the mode control unit 400 is high; when the first control unit 420 is low, no matter whether the output of the main DC / DC converter 320 is low or high, the second control switch tube Q2 is turned off, and the output of the mode control unit 400 is high.

[0071] In a specific implementation, the first control switch tube Q1 and the second control switch tube Q2 are MOSFETs, but the present application does not limit their specific types. A resistor-capacitor parallel unit is connected between the first control switch tube Q1 and the ground GND, such as a parallel unit formed by a first resistor R1 and a first capacitor C1. A resistor-capacitor parallel unit is connected between the second control switch tube Q2 and the ground GND, such as a parallel unit formed by a second resistor R2 and a second capacitor C2. When the first control switch tube Q1 and the second control switch tube Q2 are MOSFETs, their first ends are drains and their second ends are sources.

[0072] for Figure 2 The embodiment shown includes multiple photovoltaic panels, see Figure 4 The schematic diagram of the mode control unit shown in FIG. Figure 3 The third control unit 410 is also included on the basis shown, and the third control unit 410 includes a plurality of diodes, the anodes of which are used to be connected to the photovoltaic panels one by one, such as the diode D41 connected to the photovoltaic panel 21 to receive its output voltage PV1W, until the diode D4n connected to the photovoltaic panel 2n to receive its output voltage PVnW, and the cathodes are all connected to the input end of the first control unit 420. As long as the output voltage of the photovoltaic panel 21 is high, the first control switch tube Q1 is turned on, the mode control unit 400 outputs a high level, and the auxiliary DC / DC converter 310 supplies power to the maximum power point tracking circuit, so that it works to achieve maximum power point tracking, so as to charge the battery pack, where n is a natural number.

[0073] In one embodiment, the selection unit 230 is configured to select the output voltage of the second diode group 220 or the output voltage of the photovoltaic panel as the input of the auxiliary DC / DC converter 310. Specifically, when the photovoltaic panel has output, the output voltage of the photovoltaic panel is selected as the input of the auxiliary DC / DC converter 310, and when the photovoltaic panel has no output, the output voltage of the second diode group 220 is selected as the input of the auxiliary DC / DC converter 310.

[0074] Furthermore, in a specific embodiment, please refer to Figure 1 The selection unit 230 includes a first diode D31 and a second diode Db, the anode of the first diode D31 is connected to the photovoltaic panel 20, the anode of the second diode Db is connected to the output end of the second diode group 220, and the cathode of the first diode D31 and the cathode of the second diode Db are connected to the input end of the auxiliary DC / DC converter 310, so that the above-mentioned selection between the output voltage of the second diode group 220 or the output voltage of the photovoltaic panel as the input of the auxiliary DC / DC converter 310 can be realized.

[0075] For further information, see Figure 2 For a system including multiple photovoltaic panels, the selection unit 230 includes multiple first diodes, from the first diode D31 to the first diode D3n, and the anodes of the multiple first diodes are used to be connected to the photovoltaic panels one by one, so that when any photovoltaic panel has an output, the selection unit 230 selects the output voltage of the photovoltaic panel. It can be seen that at this time, the selection unit 230 receives the output voltages of all photovoltaic panels, such as PV1W to PVnW.

[0076] Please refer to Figure 1 and Figure 2 The output end of the main DC / DC converter 320 is used to connect to the load 40 through the first switch tube S1; the output end of the auxiliary DC / DC converter 310 is used to connect to the load 40 through the second switch tube S2. This realizes the decoupling between the outputs of the main DC / DC converter 320 and the auxiliary DC / DC converter 310.

[0077] In a specific embodiment, the first switch tube S1 and the second switch tube S2 are both implemented as diodes. When both the main DC / DC converter 320 and the auxiliary DC / DC converter 310 have outputs, the one with a higher output voltage is automatically selected to supply power to the load. This also serves to isolate faults, that is, when the main DC / DC converter 320 or the auxiliary DC / DC converter 310 is damaged and the output is short-circuited, the output of the other circuit will not be affected, thereby improving the reliability of the system power supply.

[0078] In a specific embodiment, if Figure 1 and Figure 2As shown, since the first switch tube S1 is in the output loop of the main DC / DC converter 320 and needs to work for a long time, the first switch tube S1 can be implemented as a switch tube (such as MOSFET) to replace the diode to reduce the additional loss caused by the diode voltage drop, and the second switch tube S2 is implemented as a diode. When the main DC / DC converter 320 has an output, the first switch tube S1 is controlled to be turned on; when the main DC / DC converter 320 has no output or a short circuit fault occurs, the body diode of the first switch tube S1 plays an isolation role to improve the reliability of the system power supply. Specifically, when the first switch tube S1 is implemented as a MOSFET, its source is connected to the output end of the main DC / DC converter 320, and the drain is used to connect the load 40.

[0079] In one embodiment, the present application also provides a photovoltaic-battery power supply system, which can be found at Figure 1 and Figure 2 , which includes the photovoltaic-battery power supply device 10 described above, and further includes a photovoltaic panel, a battery group and a load. The photovoltaic panel is connected to the maximum power point tracking circuit in the photovoltaic-battery power supply device in a one-to-one correspondence, the battery group is connected to the cathode of the diode in the first diode group in the photovoltaic-battery power supply device in a one-to-one correspondence, and the load is connected to the output end of the main DC / DC converter and the output end of the auxiliary DC / DC converter.

[0080] The principles and advantages are the same as above and will not be repeated here.

[0081] In actual implementation, the above diodes can be replaced by switch tubes (such as MOSFET) to reduce conduction loss.

[0082] The solution provided by the present application can minimize light load losses, increase the standby time of the power supply system, and ensure the reliability of power supply to the load. For example, when there is no light, the system of the present application can continue to work for a long time, such as a week or even longer.

[0083] Although the embodiments of the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims.

[0084] In addition, the scope of the present application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, material compositions, devices, methods, and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of this disclosure, processes, machines, manufactures, material compositions, means, methods, or steps that perform substantially the same functions currently exist or will later be developed or achieve substantially the same results as the corresponding embodiments described herein that can be used according to this disclosure. Therefore, the appended claims are intended to include such processes, machines, manufactures, material compositions, devices, methods, or steps within their scope.

Claims

1. A photovoltaic-battery power supply device, characterized in that: include: The maximum power point tracking circuit has an input end connected to a photovoltaic panel and an output end connected to a DC bus; A first diode group, comprising a plurality of diodes, anodes of which are all connected to the DC bus, and cathodes of which are used to be connected to the battery groups one by one; A second diode group, comprising a plurality of diodes, anodes of which are connected one-to-one with cathodes of the diodes in the first diode group, and cathodes of which are connected to each other to form an output end of the second diode group; A main DC / DC converter, having an input end connected to the output end of the second diode group and an output end for connecting to a load; A selection unit, wherein the first input end is used to connect to the photovoltaic panel, and the second output end is connected to the output end of the second diode group; An auxiliary DC / DC converter, whose input end is connected to the output end of the selection unit, and whose output end is used to connect to a load and a power supply end of the maximum power point tracking circuit; A mode control unit receives the output voltage of the photovoltaic panel and the output voltage of the main DC / DC converter, and is used to output a control signal for controlling whether the auxiliary DC / DC converter works according to the output voltage of the photovoltaic panel and the output voltage of the main DC / DC converter.

2. The photovoltaic-battery power supply device according to claim 1, characterized in that: The selection unit is configured to select an output voltage of the second diode group or an output voltage of the photovoltaic panel as an input of the auxiliary DC / DC converter.

3. The photovoltaic-battery power supply device according to claim 2, characterized in that: The selection unit includes a first diode and a second diode, the anode of the first diode is used to connect the photovoltaic panel, the anode of the second diode is connected to the output end of the second diode group, and the cathode of the first diode and the cathode of the second diode are connected to the input end of the auxiliary DC / DC converter.

4. The photovoltaic-battery power supply device according to claim 1 or 3, characterized in that: The mode control unit is configured to: When the output voltage of the photovoltaic panel is high, the control signal output by the mode control unit enables the auxiliary DC / DC converter to operate; When the output voltage of the photovoltaic panel is low and the output voltage of the main DC / DC converter is high, the control signal output by the mode control unit causes the auxiliary DC / DC converter to not work; When the output voltage of the photovoltaic panel is low and the output voltage of the main DC / DC converter is low, the control signal output by the mode control unit enables the auxiliary DC / DC converter to operate.

5. The photovoltaic-battery powered device according to claim 4, characterized in that: The control signal output by the mode control unit is used to control the control chip of the auxiliary DC / DC converter. When the control signal is at a high level, the control chip works to output a switch control signal for controlling the operation of the auxiliary DC / DC converter. When the control signal is at a low level, the control chip does not work.

6. The photovoltaic-battery power supply device according to claim 5, characterized in that: The mode control unit is implemented by a digital circuit.

7. The photovoltaic-battery powered device according to claim 5, characterized in that: The mode control unit comprises: A first control unit, the input end of which is used to receive the output voltage of the photovoltaic panel; A second control unit, an input end of which receives the output voltage of the main DC / DC converter and is connected to the output end of the first control unit, wherein when the output voltage of the photovoltaic panel is at a high level, the output end of the first control unit pulls down the input end of the second control unit, so that the second control unit outputs a high level; when the output voltage of the photovoltaic panel is at a low level, the output end of the first control unit is at a high level, and if the output voltage of the main DC / DC converter is at a low level at this time, the output of the second control unit is high, and if the output voltage of the main DC / DC converter is also at a high level at this time, the output of the second control unit is pulled down.

8. The photovoltaic-battery powered device according to claim 7, characterized in that: The first control unit includes a first control switch tube, wherein a control end of the first control switch tube forms an input end of the first control unit, a second end of the first control switch tube is grounded, and a first end of the first control switch tube forms an output end of the first control unit; The second control unit includes a second control switch tube, a control end of the second control switch tube forms an input end of the second control unit, a second end of the second control switch tube is grounded, and a first end of the second control switch tube forms an output end of the mode control unit.

9. The photovoltaic-battery powered device according to claim 8, characterized in that: There are multiple maximum power point tracking circuits, the input ends of the maximum power point tracking circuits are used to be connected to the photovoltaic panels in a one-to-one correspondence, and the output ends are connected to the DC bus; The output end of the auxiliary DC / DC converter is connected to the power supply end of all maximum power point tracking circuits; The selection unit includes a plurality of first diodes, and anodes of the plurality of first diodes are used to be connected to the photovoltaic panels in a one-to-one correspondence; The mode control unit is used to receive the output voltages of all photovoltaic panels.

10. The photovoltaic-battery powered device according to claim 9, characterized in that: The mode control unit further includes a third control unit. The third control unit includes a plurality of diodes, wherein the anodes are used to be connected to the photovoltaic panels one by one, and the cathodes are all connected to the input end of the first control unit.

11. The photovoltaic-battery powered device according to claim 1, characterized in that: The output end of the main DC / DC converter is used to connect to a load through a first switch tube; the output end of the auxiliary DC / DC converter is used to connect to a load through a second switch tube.

12. The photovoltaic-battery powered device according to claim 11, characterized in that: The first switch tube is a MOSFET; the second switch tube is a diode.

13. A photovoltaic-battery power supply system, characterized in that: include: The photovoltaic-battery powered device according to claim 1; Photovoltaic panels connected one-to-one with the maximum power point tracking circuit in the photovoltaic-battery power supply device; A battery group connected in a one-to-one correspondence with the cathodes of the diodes in the first diode group in the photovoltaic-battery powered device; A load is connected to the output end of the main DC / DC converter and the output end of the auxiliary DC / DC converter.

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