Photovoltaic-cell power supply system

Abstract

The invention provides a photovoltaic-battery power supply system, and relates to the field of power supplies, a controller controls a photovoltaic-battery power supply device to work in a first working mode, an auxiliary DC / DC converter works to convert electric energy provided by a photovoltaic battery panel or a battery pack into a first output voltage, electric energy provided by the photovoltaic cell panel charges the battery pack through the working maximum power point tracking circuit and the first diode group; in the second working mode, the auxiliary DC / DC converter and the maximum power point tracking circuit do not work, and the main DC / DC converter works to convert the electric energy provided by the battery pack into second output voltage; or in the third working mode, the main DC / DC converter and the maximum power point tracking circuit do not work, and the auxiliary DC / DC converter works to convert the electric energy provided by the battery pack into the first output voltage. The static loss of the maximum power point tracking circuit and the auxiliary DC / DC converter is reduced, the light load efficiency and standby time of the system are improved, and the reliability of supplying power to the load is high.

Description

Technical Field

[0001] The present application relates to the field of power supply, in particular to a photovoltaic-battery power supply system. 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 system, comprising: a photovoltaic-battery power supply device, comprising: a maximum power point tracking circuit, whose input end is used to be connected to a photovoltaic cell panel, and whose output end is connected to a DC bus; a first diode group, comprising a plurality of diodes, whose anodes are all connected to the DC bus, and whose cathodes are used to be connected to a battery group in a one-to-one correspondence; a second diode group, comprising a plurality of diodes, whose anodes are connected to the cathodes of the diodes in the first diode group in a one-to-one correspondence, and whose cathodes are connected to each other to form an output end of the second diode group; a main DC / DC converter, whose input end is connected to the output end of the second diode group, and whose output end is used to be connected to a load; a third diode group, whose anode of the first diode in the third diode group is used to be connected to the photovoltaic cell panel, and whose anode of the second diode in the third diode group is connected to the output end of the second diode group; an auxiliary DC / DC converter, whose input end is connected to the cathode of the diode in the third diode group, and whose output end is used to be connected to a load and a power supply end of the maximum power point tracking circuit;

[0006] A controller, wherein the controller is configured to control the photovoltaic-battery powered device to operate in one of a plurality of operating modes, wherein the plurality of operating modes include:

[0007] In the first working mode, the auxiliary DC / DC converter works to convert the electric energy provided by the photovoltaic panel or the battery group into a first output voltage, and the electric energy provided by the photovoltaic panel charges the battery group through the working maximum power point tracking circuit and the first diode group;

[0008] In a second working mode, the auxiliary DC / DC converter and the maximum power point tracking circuit do not work, and the main DC / DC converter works to convert the electric energy provided by the battery pack into a second output voltage;

[0009] In the third working mode, the main DC / DC converter and the maximum power point tracking circuit do not work, and the auxiliary DC / DC converter works to convert the electric energy provided by the battery pack into a first output voltage.

[0010] Furthermore, the first working mode also includes:

[0011] The main DC / DC converter works to convert the electric energy provided by the battery pack into the second output voltage, and the higher of the first output voltage and the second output voltage supplies power to the load; or

[0012] The main DC / DC converter does not work, and the first output voltage supplies power to the load.

[0013] Furthermore, in the first working mode, the diode in the first diode group connected to the battery group with a low voltage is turned on first.

[0014] Furthermore, in the first working mode, the diode in the second diode group connected to the battery group with a higher voltage is turned on first.

[0015] Furthermore, in the first working mode, the diodes with higher anode voltages in the third diode group are turned on first.

[0016] Furthermore, in the second working mode, the diodes in the first diode group are all cut off;

[0017] The diode in the second diode group connected to the battery group with a higher voltage is turned on first.

[0018] Furthermore, in the third working mode, the diodes in the first diode group are all cut off;

[0019] The diode in the second diode group connected to the battery group with a high voltage is turned on first;

[0020] The second diode in the third diode group is turned on, and the first diode in the third diode group is turned off.

[0021] Furthermore, the output end of the main DC / DC converter is connected to the load through a first switch tube; the output end of the auxiliary DC / DC converter is connected to the load through a second switch tube, wherein

[0022] In the first working mode, both the first switch tube and the second switch tube are turned on;

[0023] In the second working mode, the first switch tube is turned on, and the second switch tube is turned off;

[0024] In the third working mode, the first switch tube is turned off, and the second switch tube is turned on.

[0025] Furthermore, there are multiple maximum power point tracking circuits, multiple photovoltaic panels, and the input end of the maximum power point tracking circuit is connected to the photovoltaic panels one by one; the output end of the auxiliary DC / DC converter is connected to the power supply end of all maximum power point tracking circuits; the third diode group includes multiple first diodes, and the multiple first diodes are connected to the photovoltaic panels one by one, wherein

[0026] In the first working mode, the diode with a higher anode voltage in the third diode group is turned on first;

[0027] In the second working mode, all the first diodes and the second diodes in the third diode group are cut off;

[0028] In the third working mode, the first diodes in the third diode group are all turned off, and the second diodes are turned on.

[0029] Furthermore, the controller executes:

[0030] S1: Determine whether the photovoltaic panel outputs power. If so, control the photovoltaic-battery power supply device to operate in the first operating mode. If not, proceed to step S2;

[0031] S2: Determine whether the main DC / DC converter operates normally. If so, control the photovoltaic-battery power supply device to operate in the second operating mode. If not, control the photovoltaic-battery power supply device to operate in the third operating mode.

[0032] Furthermore, the first working mode of step S1 also includes:

[0033] Determine whether the main DC / DC converter is working normally. If so, control the main DC / DC converter to work to convert the electric energy provided by the battery pack into the second output voltage, and the higher of the first output voltage and the second output voltage is used to power the load. If not, control the main DC / DC converter not to work, and the first output voltage is used to power the load.

[0034] 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

[0035] 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:

[0036] Figure 1 A schematic diagram of a photovoltaic-battery power supply system according to an embodiment of the present application is shown;

[0037] Figure 2 A schematic diagram of a photovoltaic-battery power supply system according to another embodiment of the present application is shown;

[0038] Figure 3 Shows Figure 1 A schematic diagram of the photovoltaic-battery power supply system in the second working mode;

[0039] Figure 4 Shows Figure 1 A schematic diagram of the photovoltaic-battery power supply system in the third working mode;

[0040] Figure 5 Shows Figure 2 A schematic diagram of the photovoltaic-battery power supply system in the second working mode;

[0041] Figure 6 Shows Figure 2 A schematic diagram of the photovoltaic-battery power supply system in the third working mode;

[0042] Figure 7 Shows Figure 1 A schematic diagram of a mode control unit in FIG.

[0043] Figure 8 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 provides a photovoltaic-battery power supply system. Figure 1 The photovoltaic-battery power supply system of one embodiment of the present application is shown, the photovoltaic-battery power supply system includes a photovoltaic-battery power supply device 10, a photovoltaic battery panel 20, a load 40, a plurality of battery groups (a first battery group 31 to an nth battery group 3n) and a controller 50, 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 third diode group 230, wherein the anode of the first diode D31 is used to connect to the photovoltaic panel 20, and the anode of the second diode Db is connected to the output end of the second diode group 220;

[0052] The auxiliary DC / DC converter 310 has an input end connected to the cathode of the diode in the third diode group 230 , and an output end connected to the load 40 and the power supply end of the maximum power point tracking circuit 100 .

[0053] 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 as an example. In practical applications, multiple photovoltaic panels and corresponding multiple 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 multiple maximum power point tracking circuits, such as 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 20 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 20, 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).

[0054] Specifically, the controller 50 is configured to control the photovoltaic-battery powered device 10 to work. The photovoltaic-battery powered device 10 of the present application can work in one of a plurality of working modes, and the plurality of working modes include:

[0055] In the first working mode, the auxiliary DC / DC converter 310 works to convert the electric energy provided by the photovoltaic panel 20 or the battery group into the first output voltage Vfo, and the electric energy provided by the photovoltaic panel 20 charges the battery group through the working maximum power point tracking circuit 100 and the first diode group 210;

[0056] In the second working mode, the auxiliary DC / DC converter 310 and the maximum power point tracking circuit 100 do not work, and the main DC / DC converter 320 works to convert the electric energy provided by the battery pack into the second output voltage Vmo;

[0057] In the third working mode, the main DC / DC converter 320 and the maximum power point tracking circuit 100 do not work, and the auxiliary DC / DC converter 310 works to convert the electric energy provided by the battery pack into the first output voltage Vfo.

[0058] When the photovoltaic-battery powered device 10 operates in the first operating mode, Figure 1 At this time, 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 works to track the maximum power point of the electric energy provided by the photovoltaic panel to store the most energy in the battery pack.

[0059] See also Figure 3 shown Figure 1Schematic diagram of the photovoltaic-battery power supply device 10 working in the second working mode. 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, the main DC / DC converter 320 works to convert the power provided by the battery group into the second output voltage Vmo to power the load. At this time, the auxiliary DC / DC converter 310 does not work, and the maximum power point tracking circuit 100 also does not work, which reduces the static loss of the maximum power point tracking circuit 100 and the auxiliary DC / DC converter 310.

[0060] See also Figure 4 shown Figure 1 The schematic diagram of the photovoltaic-battery power supply device 10 working in the third working mode is that 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 convert the electric energy provided by the battery pack into the first output voltage Vfo to power the load, which ensures the reliability of powering the load.

[0061] Similarly, for Figure 2 In the photovoltaic-battery power supply system shown, in the first working mode, the output end of the auxiliary DC / DC converter 310 supplies power to all the maximum power point tracking circuits (maximum power point tracking circuit 101 to maximum power point tracking circuit 10n), and all the maximum power point tracking circuits are in operation. That is, all the maximum power point tracking circuits are powered by a unified power supply. Compared with the prior art solution that each maximum power point tracking circuit uses 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.

[0062] Similarly, see Figure 5 shown Figure 2 The schematic diagram of the photovoltaic-battery power supply device 10 in the second working mode is 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, the main DC / DC converter 320 works to convert the power provided by the battery group into the second output voltage Vmo to power the load. At this time, the auxiliary DC / DC converter 310 does not work, and all the maximum power point tracking circuits 100 (maximum power point tracking circuit 101 to maximum power point tracking circuit 10n) also do not work, which reduces the static loss of the maximum power point tracking circuit 100 and the auxiliary DC / DC converter 310.

[0063] Similarly, see Figure 6 shown Figure 2The schematic diagram of the photovoltaic-battery power supply device 10 working in the third working mode is that 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 convert the electric energy provided by the battery pack into the first output voltage Vfo to power the load, which ensures the reliability of powering the load.

[0064] Furthermore, in the third working mode, although the auxiliary DC / DC converter 310 outputs the first output voltage Vfo to power the maximum power point tracking circuit, the controller 50 can control the maximum power point tracking circuit not to work, such as not outputting a switch control signal to it, so as to reduce its static loss.

[0065] Furthermore, in one embodiment, the first working mode also includes: the main DC / DC converter works to convert the electric energy provided by the battery group into the second output voltage, and the higher of the first output voltage and the second output voltage supplies power to the load; or the main DC / DC converter does not work, and the first output voltage supplies power to the load. That is, when the output voltage of the photovoltaic panel is high (with light), if the main DC / DC converter 320 can work normally, the main DC / DC converter 320 also works, and 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. Among them, when the DC / DC converter 320 also works, the diode connected to the battery group with high voltage in the second diode group 220 is turned on first.

[0066] As described above, 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.

[0067] Furthermore, Figure 1As 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.

[0068] 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.

[0069] 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.

[0070] Furthermore, in the first working mode, see Figure 1 and Figure 2 , the diode with a higher anode voltage in the third diode group 230 is turned on first. That is, the higher voltage between the voltage provided by the photovoltaic panel and the voltage of the battery group output through the second diode group 220 supplies power to the auxiliary DC / DC converter 310 first.

[0071] Furthermore, in the second working mode, see Figure 3 and Figure 5, the diodes in the first diode group 210 are all turned off; the diodes in the second diode group 220 connected to the battery group with high voltage are turned on first to supply power to the main DC / DC converter 320, and at the same time automatically achieve voltage balance between the battery groups.

[0072] Furthermore, in the third working mode, see Figure 4 and Figure 6 , the diodes in the first diode group 210 are all turned off; the diodes in the second diode group 220 connected to the battery group with a high voltage are turned on first, the second diode Db in the third diode group 230 is turned on, and the first diode D31 (or the first diode D31 to the first diode D3n) in the third diode group 230 is turned off, so that the battery group supplies power to the main DC / DC converter 320 and automatically achieves voltage balance between the battery groups at the same time.

[0073] 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.

[0074] like Figure 2 As shown, 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 use a unified power supply. Compared with the solution of each maximum power point tracking circuit using an auxiliary power supply in the prior art, 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.

[0075] In practical applications, in a specific embodiment, the controller 50 is implemented by a digital circuit, and may also be implemented by an analog circuit, or a combination of an analog circuit and a digital circuit.

[0076] When it is implemented by analog circuits, or by a combination of analog circuits and digital circuits, in a specific embodiment, the controller 50 includes Figure 7 Mode control unit shown, and see Figure 1The 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.

[0077] In one specific embodiment, see Figure 7 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 PVW 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 PVW of the photovoltaic panel 20 is low, the first control switch tube Q1 is turned off, and the first control unit 420 is high.

[0078] 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.

[0079] 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.

[0080] for Figure 2 In the embodiment shown, which includes a plurality of photovoltaic panels, the controller 50 includes Figure 8 The mode control unit shown in Figure 7 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.

[0081] For further information, see Figure 2For a system including multiple photovoltaic panels, the third diode group 230 includes multiple first diodes, diode D31 to diode D3n, and the anodes of the multiple first diodes are used to be connected to the photovoltaic panels one by one. Then, when any photovoltaic panel has an output, the third diode group 230 selects the output voltage of the photovoltaic panel. It can be seen that the third diode group 230 receives the output voltages of all photovoltaic panels, such as PV1W to PVnW.

[0082] Please refer to Figure 1 and Figure 2 The output end of the main DC / DC converter 320 is connected to the load 40 through the first switch tube S1; the output end of the auxiliary DC / DC converter 310 is connected to the load 40 through the second switch tube S2, so as to achieve decoupling between the outputs of the main DC / DC converter 320 and the auxiliary DC / DC converter 310.

[0083] 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.

[0084] In a specific embodiment, if Figure 1 and Figure 2 As 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.

[0085] More specifically, in the first working mode, both the first switch tube S1 and the second switch tube S2 are turned on; in the second working mode, the first switch tube S1 is turned on and the second switch tube S2 is turned off; in the third working mode, the first switch tube S1 is turned off and the second switch tube S2 is turned on.

[0086] Furthermore, in order to control the photovoltaic-battery powered device to operate in a desired operating mode, the controller 50 executes:

[0087] S1: Determine whether the photovoltaic panel outputs power. If so, control the photovoltaic-battery power supply device 10 to work in the first working mode. If not, proceed to step S2;

[0088] S2: Determine whether the main DC / DC converter 320 is operating normally. If so, control the photovoltaic-battery powered device 10 to operate in the second operating mode. If not, control the photovoltaic-battery powered device 10 to operate in the third operating mode.

[0089] Furthermore, the first working mode in step S1 also includes: determining whether the main DC / DC converter 320 is operating normally, and if so, controlling the main DC / DC converter 320 to operate to convert the electric energy provided by the battery pack into the second output voltage Vmo, and the higher of the first output voltage Vfo and the second output voltage Vmo supplies power to the load 40; if not, controlling the main DC / DC converter 320 not to operate, and the first output voltage Vfo supplies power to the load 40.

[0090] In actual implementation, the above diodes can be replaced by switch tubes (such as MOSFET) to reduce conduction loss.

[0091] 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.

[0092] 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.

[0093] 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 system, characterized in that: include: A photovoltaic-battery power supply device, comprising: a maximum power point tracking circuit, whose input end is used to be connected to a photovoltaic panel, and whose output end is connected to a DC bus; a first diode group, comprising a plurality of diodes, whose anodes are all connected to the DC bus, and whose cathodes are used to be connected to a battery group in a one-to-one correspondence; a second diode group, comprising a plurality of diodes, whose anodes are connected to the cathodes of the diodes in the first diode group in a one-to-one correspondence, and whose cathodes are connected to each other to form an output end of the second diode group; a main DC / DC converter, whose input end is connected to the output end of the second diode group, and whose output end is used to be connected to a load; a third diode group, whose anode of the first diode in the third diode group is used to be connected to the photovoltaic panel, and whose anode of the second diode in the third diode group is connected to the output end of the second diode group; an auxiliary DC / DC converter, whose input end is connected to the cathode of the diode in the third diode group, and whose output end is used to be connected to a load and a power supply end of the maximum power point tracking circuit; A controller, wherein the controller is configured to control the photovoltaic-battery powered device to operate in one of a plurality of operating modes, wherein the plurality of operating modes include: In the first working mode, the auxiliary DC / DC converter works to convert the electric energy provided by the photovoltaic panel or the battery group into a first output voltage, and the electric energy provided by the photovoltaic panel charges the battery group through the working maximum power point tracking circuit and the first diode group; In a second working mode, the auxiliary DC / DC converter and the maximum power point tracking circuit do not work, and the main DC / DC converter works to convert the electric energy provided by the battery pack into a second output voltage; In the third working mode, the main DC / DC converter and the maximum power point tracking circuit do not work, and the auxiliary DC / DC converter works to convert the electric energy provided by the battery pack into a first output voltage.

2. The photovoltaic-battery power supply system according to claim 1, characterized in that: The first working mode also includes: The main DC / DC converter works to convert the electric energy provided by the battery pack into the second output voltage, and the higher of the first output voltage and the second output voltage supplies power to the load; or The main DC / DC converter does not work, and the first output voltage supplies power to the load.

3. The photovoltaic-battery power supply system according to claim 1, characterized in that: In the first working mode, the diode in the first diode group connected to the battery group with a low voltage is turned on first.

4. The photovoltaic-battery power supply system according to claim 1, characterized in that: In the first working mode, the diodes in the second diode group connected to the battery group with a high voltage are turned on first.

5. The photovoltaic-battery power supply system according to claim 1, characterized in that: In the first working mode, the diodes with higher anode voltages in the third diode group are turned on first.

6. The photovoltaic-battery power supply system according to claim 1, characterized in that: In the second working mode, the diodes in the first diode group are all cut off; The diode in the second diode group connected to the battery group with a higher voltage is turned on first.

7. The photovoltaic-battery power supply system according to claim 1, characterized in that: In the third working mode, all diodes in the first diode group are cut off; The diode in the second diode group connected to the battery group with a high voltage is turned on first; The second diode in the third diode group is turned on, and the first diode in the third diode group is turned off.

8. The photovoltaic-battery power supply system according to claim 1, characterized in that: The output end of the main DC / DC converter is connected to the load through a first switch tube; the output end of the auxiliary DC / DC converter is connected to the load through a second switch tube, wherein In the first working mode, both the first switch tube and the second switch tube are turned on; In the second working mode, the first switch tube is turned on, and the second switch tube is turned off; In the third working mode, the first switch tube is turned off, and the second switch tube is turned on.

9. The photovoltaic-battery power supply system according to claim 1, characterized in that: There are multiple maximum power point tracking circuits, there are multiple photovoltaic panels, and the input end of the maximum power point tracking circuit is connected to the photovoltaic panels one by one; the output end of the auxiliary DC / DC converter is connected to the power supply end of all maximum power point tracking circuits; the third diode group includes multiple first diodes, and the multiple first diodes are connected to the photovoltaic panels one by one, wherein In the first working mode, the diode with a higher anode voltage in the third diode group is turned on first; In the second working mode, all the first diodes and the second diodes in the third diode group are cut off; In the third working mode, the first diodes in the third diode group are all turned off, and the second diodes are turned on.

10. The photovoltaic-battery power supply system according to claim 1 or 9, characterized in that: The controller executes: S1: Determine whether the photovoltaic panel outputs power. If so, control the photovoltaic-battery power supply device to operate in the first operating mode. If not, proceed to step S2; S2: Determine whether the main DC / DC converter operates normally. If so, control the photovoltaic-battery power supply device to operate in the second operating mode. If not, control the photovoltaic-battery power supply device to operate in the third operating mode.

11. The photovoltaic-battery power supply system according to claim 10, characterized in that: The first working mode of step S1 also includes: Determine whether the main DC / DC converter is working normally. If so, control the main DC / DC converter to work to convert the electric energy provided by the battery pack into the second output voltage, and the higher of the first output voltage and the second output voltage is used to power the load. If not, control the main DC / DC converter not to work, and the first output voltage is used to power the load.

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