Multi-path photovoltaic parallel pre-charging circuit and energy storage power supply thereof

Abstract

The embodiment of the invention discloses a multi-path photovoltaic parallel pre-charging circuit and an energy storage power supply thereof, the multi-path photovoltaic parallel pre-charging circuit comprises a multi-path photovoltaic power supply module, a pre-charging module and a control module, and the photovoltaic power supply module comprises a switch unit, a first energy storage unit, a voltage conversion unit and a second energy storage unit; the control module is used for controlling the pre-charging module to work when the photovoltaic power supply module is pre-charged; the pre-charging voltage output by the pre-charging module is used for pre-charging the second energy storage unit and pre-charging the first energy storage unit through the voltage conversion unit; and when the photovoltaic power supply module normally supplies power, the switch unit is controlled to be switched on, so that electric energy is supplied to a post-stage through the switch unit, the first energy storage unit, the voltage conversion unit and the second energy storage unit in sequence. According to the embodiment of the invention, the control module detects the input voltage and controls the pre-charging module to work so as to pre-charge the second energy storage unit and the first energy storage unit, the switch unit is switched on on the premise of avoiding large current impact, and the circuit cost can be reduced.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of photovoltaic charging, and particularly to a multi-path photovoltaic parallel pre-charge circuit and its energy storage power supply. Background Art

[0002] With the increasing number of RV owners, there are more and more scenarios of using solar panels to power household appliances outdoors. Since the open-circuit voltage of solar energy is generally relatively large, PV chargers generally have an input pre-charge circuit. Moreover, when the RV is driving, it often passes through areas where sunlight cannot reach. If the PV input relay is frequently switched, it will affect the relay life and generate noise. Therefore, a weak photovoltaic identification circuit is also essential.

[0003] Traditional pre-charge circuits and weak photovoltaic identification circuits are separate. Moreover, if a multi-path PV circuit parallel output method is used, each path requires a separate pre-charge circuit and weak photovoltaic identification circuit, resulting in a relatively high cost. Summary of the Invention

[0004] The main technical problem to be solved by the embodiments of the present invention is to provide a multi-path photovoltaic parallel pre-charge circuit and its energy storage power supply, which can solve some problems existing in the existing photovoltaic pre-charge circuit.

[0005] To solve the above technical problem, in a first aspect, embodiments of the present invention provide a multi-path photovoltaic parallel pre-charge circuit, including: a multi-path photovoltaic power supply module, a pre-charge module, and a control module. Each photovoltaic power supply module includes a switch unit, a first energy storage unit, a voltage conversion unit, and a second energy storage unit connected in sequence. The input end of the switch unit is also used to connect to the pre-charge module and a photovoltaic input source. The pre-charge module is also connected to each second energy storage unit. The control module is respectively connected to the switch unit and the pre-charge module. The control module is used to control the pre-charge module to work when the photovoltaic power supply module is pre-charging, so that the pre-charge voltage output by the pre-charge module pre-charges the second energy storage unit and pre-charges the first energy storage unit through the voltage conversion unit. And when the photovoltaic power supply module is supplying power normally, the control module controls the switch unit to conduct, so that the electric energy of the photovoltaic input source sequentially passes through the switch unit, the first energy storage unit, the voltage conversion unit, and the second energy storage unit to supply power to the subsequent stage.

[0006] Optionally, the control module is used to control the pre-charge module to work and control the switch unit to disconnect when the photovoltaic power supply module is pre-charging. And when the multi-path photovoltaic power supply module is supplying power normally, the control module controls the switch unit to conduct and controls the pre-charge module to stop working.

[0007] Optionally, for each photovoltaic power supply module, the voltage conversion unit is configured to convert the pre-charge voltage output by the pre-charge module to a preset voltage to pre-charge the first energy storage unit when the photovoltaic power supply module is pre-charged; wherein, the difference between the preset voltage and the voltage of the photovoltaic input source connected to the photovoltaic power supply module is within a first preset range.

[0008] Optionally, the control module is further configured to determine whether the corresponding photovoltaic input source is in a weak voltage state according to the voltage of the photovoltaic input source connected to each photovoltaic power supply module after the pre-charge module operates.

[0009] Optionally, the pre-charge module is a constant current pre-charge module.

[0010] Optionally, the pre-charge module includes a plurality of protection diodes, inductors LD2, LD3, capacitor CE4, switching transistor Q3, diode D2, and capacitor CE5. The anode of each protection diode is connected to the input end of the switching unit of each photovoltaic power supply module, and the cathode of each protection diode is connected to the first end of inductor LD2. The second end of inductor LD2, the first end of capacitor CE4, and the drain of switching transistor Q3 are connected. The source of switching transistor Q3, the cathode of diode D2, and the first end of inductor LD3 are connected. The second end of inductor LD3, the first end of capacitor CE5, and the second energy storage unit of each photovoltaic power supply module are connected. The gate of switching transistor Q3 is connected to the control module. The second ends of capacitor CE4 and capacitor CE5 and the anode of diode D2 are connected to the reference ground.

[0011] Optionally, the plurality of protection diodes are all Schottky diodes.

[0012] Optionally, both the first energy storage unit and the second energy storage unit are energy storage capacitors.

[0013] Optionally, the voltage conversion unit includes a first inductor, a first switching transistor, and a second switching transistor. The first end of the first inductor is connected to the first energy storage unit and the output end of the switching unit. The second end of the first inductor is connected to the drain of the second switching transistor and the source of the first switching transistor. The drain of the first switching transistor is connected to the second energy storage unit and the output end of the pre-charge module. The source of the second switching transistor is connected to the reference ground. The gates of the first switching transistor and the second switching transistor are connected to the control module.

[0014] In a second aspect, an embodiment of the present invention provides an energy storage power supply, including: a multi-path photovoltaic parallel pre-charge circuit as described in the first aspect.

[0015] The beneficial effects of the embodiments of the present invention are as follows: Different from the prior art, the embodiments of the present invention detect the input voltage through a control module and control the operation of a pre-charging module to pre-charge the second energy storage units of multiple photovoltaic power supply modules respectively, and pre-charge the first energy storage unit through a corresponding voltage conversion unit. On the premise of avoiding large current impact, a switching unit is turned on, and the control module realizes low-light detection. That is, through the above pre-charging logic, multiple photovoltaic power supply modules share one pre-charging module, and there is no need to set a pre-charging module in each photovoltaic power supply module, thus reducing the circuit cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. is a schematic structural diagram of a multi-path photovoltaic parallel pre-charging circuit provided by an embodiment of the present invention;

[0017] Figure 2 FIG. is a circuit schematic diagram of a multi-path photovoltaic parallel pre-charging circuit provided by an embodiment of the present invention;

[0018] Figure 3 FIG. is a circuit schematic diagram of another multi-path photovoltaic parallel pre-charging circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To facilitate the understanding of the present application, the present application will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is expressed as "fixed to" another element, it can be directly on the other element, or there can be one or more intermediate elements therebetween. When an element is expressed as "connected to" another element, it can be directly connected to the other element, or there can be one or more intermediate elements therebetween. The terms "upper", "lower", "inner", "outer", "bottom", etc. used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0020] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in this specification in the description of the present application are only for the purpose of describing specific embodiments and are not used to limit the present application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0021] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0022] Hereinafter, the technical solutions in the present application will be described with reference to the accompanying drawings.

[0023] Refer to Figure 1 As shown, the multi-path photovoltaic parallel pre-charge circuit provided in this embodiment includes a photovoltaic power supply module 310, a photovoltaic power supply module 320, a photovoltaic power supply module 3N0, a pre-charge module 200, and a control module 100.

[0024] Each photovoltaic power supply module includes a switch unit, a first energy storage unit, a voltage conversion unit, and a second energy storage unit connected in sequence. Taking the first photovoltaic power supply module 310 as an example, it includes a switch unit 311, a first energy storage unit 312, a voltage conversion unit 313, and a second energy storage unit 314. The second photovoltaic power supply module 320 includes a switch unit 321, a first energy storage unit 322, a voltage conversion unit 323, and a second energy storage unit 324. The Nth photovoltaic power supply module 3N0 includes a switch unit 3N1, a first energy storage unit 3N2, a voltage conversion unit 3N3, and a second energy storage unit 3N4.

[0025] In this embodiment, the input end of the switch unit of each photovoltaic power supply module is also used to be connected to the pre-charge module 200 and a photovoltaic input source. The pre-charge module 200 is also connected to each second energy storage unit. The control module 100 is respectively connected to the switch unit of each photovoltaic power supply module and the pre-charge module 200.

[0026] The control module 100 is used to control the pre-charge module 200 to work when pre-charging each photovoltaic power supply module, so that the pre-charge voltage output by the pre-charge module 200 pre-charges the second energy storage unit of each photovoltaic power supply module and pre-charges the corresponding first energy storage unit through the voltage conversion unit of each photovoltaic power supply module; the control module 100 is also used to control the corresponding switch unit to conduct when each photovoltaic power supply module is normally powered, so that the electric energy of the photovoltaic input source sequentially passes through the switch unit, the first energy storage unit, the voltage conversion unit, and the second energy storage unit to supply power to the subsequent stage.

[0027] In this embodiment, the control module 100 is used to control the pre-charge module 200 to work and control the corresponding switch unit to disconnect when pre-charging the photovoltaic power supply module; and control the corresponding switch unit to conduct and control the pre-charge module 200 to stop working when the multi-path photovoltaic power supply module is normally powered.

[0028] Specifically, for each photovoltaic power supply module, the voltage conversion unit is configured to convert the pre-charge voltage output by the pre-charge module 200 to a preset voltage during the pre-charging of the photovoltaic power supply module, so as to pre-charge the corresponding first energy storage unit; wherein, the difference between the preset voltage and the voltage of the photovoltaic input source connected to the photovoltaic power supply module is within a first preset range.

[0029] In a multi-path photovoltaic system, the voltages of different photovoltaic input sources may vary. The charging of the first energy storage unit needs to be carried out within a specific voltage range to ensure charging efficiency and safety. Therefore, the main function of the voltage conversion unit is to convert the pre-charge voltage output by the pre-charge module to a voltage level more suitable for charging the first energy storage unit.

[0030] In addition, during the pre-charging process, the selection of the preset voltage is crucial. In this embodiment, it is stipulated that the difference between the preset voltage and the voltage of the photovoltaic input source connected to the photovoltaic power supply module needs to be kept within a first preset range. If the difference between the preset voltage and the photovoltaic input source voltage is too large, a large transient current may be generated when the switching unit is turned on, damaging the circuit components. By controlling the difference between the two within the first preset range, the current impact at the moment of conduction can be effectively reduced. At the same time, when the pre-charge voltage of the first energy storage unit is close to the photovoltaic input source voltage, the voltage balance between the first energy storage unit and the photovoltaic input source will be achieved faster during subsequent normal operation, reducing energy conversion losses.

[0031] In practical applications, the specific value of the first preset range needs to be reasonably set according to system parameters. For example, in a typical photovoltaic charging system, this range may be set between 5V and 15V. If the voltage of the photovoltaic input source is 60V, the preset voltage may be set to a value between 50V and 60V to ensure that the difference falls within the first preset range.

[0032] By way of example and not limitation, the specific circuit structure for the voltage conversion unit to achieve this voltage conversion function can adopt various forms, such as a DC-DC converter, a Buck converter, or other types of voltage conversion circuits. In this embodiment, the voltage conversion unit may include components such as an inductor, a switching transistor, and a control circuit, and achieve precise voltage conversion by adjusting the conduction time and frequency of the switching transistor.

[0033] The following is an example: when the voltage of the photovoltaic input source is 60V, the preset voltage is 50V, and the first preset range is 10V, the control module 100 controls the voltage conversion unit to convert the pre-charge voltage output by the pre-charge module 200 into 50V. The difference between this voltage and the voltage of the photovoltaic input source is 10V, which is within the first preset range. By controlling the difference between the preset voltage and the voltage of the photovoltaic input source within the first preset range, it is possible to ensure the charging effect of the first energy storage unit while avoiding large current shocks caused by excessive voltage differences.

[0034] In addition, the control module 100 is further configured to, after the pre-charge module 200 operates, determine whether the corresponding photovoltaic input source is in a weak voltage state according to the voltage of the photovoltaic input source connected to each photovoltaic power supply module. Specifically, the pre-charge module 200 is a constant current pre-charge module. When the pre-charge module 200 operates, the pre-charge module 200 obtains a certain current from the photovoltaic input source, resulting in a decrease in the voltage of the photovoltaic input source. By monitoring the decrease amplitude of the voltage of the photovoltaic input source, the control module 100 can determine whether the photovoltaic input source is in a weak voltage state. For example, if the voltage of the photovoltaic input source drops significantly after the pre-charge module 200 operates and is lower than the preset threshold, it can be determined that the photovoltaic input source is in a weak voltage state.

[0035] When the photovoltaic input source is determined to be in a weak voltage state, the control module 100 can choose not to turn on the corresponding switch unit, avoiding frequent connection and disconnection of the photovoltaic input source under weak light conditions, thereby extending the service life of the switch unit (such as a relay) and reducing noise.

[0036] The working process of the multi-path photovoltaic parallel pre-charge circuit provided in this embodiment is as follows: First, the control module 100 detects the input voltage of the photovoltaic input source; then, the control module 100 controls the pre-charge module 200 to operate to pre-charge the second energy storage unit, and at the same time pre-charge the first energy storage unit through the voltage conversion unit; during the pre-charge process, the control module 100 determines whether the photovoltaic input source is in a weak voltage state according to the voltage change of the photovoltaic input source; finally, when the voltages of the first energy storage unit and the second energy storage unit reach the preset conditions (for example, close to the voltage of the photovoltaic input source), if it is determined that the photovoltaic input source is not in a weak voltage state, the control module 100 controls the switch unit to turn on and controls the pre-charge module to stop operating, so that the electric energy of the photovoltaic input source is supplied to the subsequent stage through the switch unit, the first energy storage unit, the voltage conversion unit, and the second energy storage unit in sequence.

[0037] Through the above embodiments, it can be seen that the multi-path photovoltaic parallel pre-charge circuit provided by this embodiment detects the input voltage through the control module 100 and controls the operation of the pre-charge module 200 to pre-charge the second energy storage unit of the multi-path photovoltaic power supply module respectively, and pre-charge the first energy storage unit through the corresponding voltage conversion unit. On the premise of avoiding large current impact, the switch unit is turned on, and weak light detection is realized through the control module 100. Compared with the design of traditional technology in which each path of photovoltaic requires a separate pre-charge and weak light detection circuit, the circuit cost is reduced.

[0038] In addition, while realizing the pre-charge function, the multi-path photovoltaic parallel pre-charge circuit provided by this embodiment also realizes the weak photovoltaic recognition function. By judging the change of the photovoltaic voltage during the pre-charge process to identify whether the photovoltaic is in a weak light state, unnecessary relay switching operations in the weak light state are avoided, the service life of the relay is prolonged, and the noise is reduced.

[0039] Figure 2 The circuit schematic diagram of the multi-path photovoltaic parallel pre-charge circuit provided by the embodiment of the present application is shown. For convenience of description, only two paths of photovoltaic power supply modules are provided in the multi-path photovoltaic parallel pre-charge circuit provided in this embodiment, namely the photovoltaic power supply module 310 and the photovoltaic power supply module 320. In other embodiments, the number of photovoltaic power supply modules can be increased according to the actual application scenario.

[0040] Refer to Figure 2 As shown, according to the multi-path photovoltaic parallel pre-charge circuit provided by this embodiment, the pre-charge module 200 includes a plurality of protection diodes, inductors LD2, LD3, capacitor CE4, switch tube Q3, diode D2 and capacitor CE5. The number of protection diodes corresponds to the number of photovoltaic power supply modules. Therefore, the pre-charge module provided by this embodiment includes protection diodes DS1 and DS2.

[0041] In this embodiment, the plurality of protection diodes are all Schottky diodes. Compared with ordinary diodes, Schottky diodes have the characteristics of low forward voltage drop and short reverse recovery time, and are more suitable for use in protection circuit applications. Each path of photovoltaic input terminal is connected to the pre-charge module through a Schottky diode, which can prevent mutual interference between photovoltaic input sources and protect the pre-charge module from high voltage impact at the same time.

[0042] For the first path of photovoltaic power supply module 310, the switch unit 311 includes a relay RLY1, the first energy storage unit 312 includes capacitors CE1 and CE2, the voltage conversion unit 313 includes a first inductor LD1, a first switch tube Q1 and a second switch tube Q2, and the second energy storage unit 314 includes a capacitor CE3.

[0043] For the second photovoltaic power supply module 320, the switch unit 321 includes a relay RLY2, the first energy storage unit 322 includes capacitors CE6 and CE7, the voltage conversion unit 323 includes a first inductor LD4, a first switching transistor Q4, and a second switching transistor Q5, and the second energy storage unit 324 includes a capacitor CE8.

[0044] The anode of the protection diode DS1 is connected to PV input 1, the anode of the protection diode DS2 is connected to PV input 2, the cathodes of the protection diode DS1 and the protection diode DS21 are connected to the first end of the inductor LD2, the second end of the inductor LD2, the first end of the capacitor CE4, and the drain of the switching transistor Q3 are connected, the source of the switching transistor Q3, the cathode of the diode D2, and the first end of the inductor LD3 are connected, the second end of the inductor LD3, the first end of the capacitor CE5, the first end of the capacitor CE3, and the first end of the capacitor CE8 are connected, the gate of the switching transistor Q3 is connected to the control module 100, and the second ends of the capacitor CE4, the capacitor CE5, and the anode of the diode D2 are connected to the reference ground BAT_GND.

[0045] The first pin and the second pin of the relay RLY1 are connected to the control module 100, the fourth pin of the relay RLY1 is connected to PV input 1, the third pin of the relay RLY1 is connected to the first end of the first inductor LD1, the first end of the capacitor CE1, and the first end of the capacitor CE2, the second end of the first inductor LD1, the drain of the second switching transistor Q2, and the source of the first switching transistor Q1 are connected, the drain of the first switching transistor Q1, the first end of the capacitor CE3, and the second end of the inductor LD3 are connected, the second ends of the capacitor CE1, the capacitor CE2, the capacitor CE3, and the source of the second switching transistor Q2 are connected to the reference ground BAT_GND, and the gates of the first switching transistor Q1 and the second switching transistor Q2 are connected to the control module 100.

[0046] The first pin and the second pin of the relay RLY2 are connected to the control module 100, the fourth pin of the relay RLY2 is connected to PV input 2, the third pin of the relay RLY2 is connected to the first end of the first inductor LD4, the first end of the capacitor CE6, and the first end of the capacitor CE7, the second end of the first inductor LD4, the drain of the second switching transistor Q5, and the source of the first switching transistor Q4 are connected, the drain of the first switching transistor Q4, the first end of the capacitor CE8, and the second end of the inductor LD3 are connected, the second ends of the capacitor CE6, the capacitor CE7, the capacitor CE8, and the source of the second switching transistor Q5 are connected to the reference ground BAT_GND, and the gates of the first switching transistor Q4 and the second switching transistor Q5 are connected to the control module 100.

[0047] The working principle of the pre-charge module 200 is as follows: When the control module 100 detects that there is voltage in any one of the PV inputs, the control module 100 makes the switching transistor Q3 conduct by controlling its gate voltage. At this time, the PV input voltage charges the capacitor CE5 through the protection diode DS1 or the protection diode DS2, the inductor LD2, the switching transistor Q3, and the inductor LD3. At the same time, it also charges the second energy storage units (such as capacitors CE3, CE8, etc.) of each PV power supply module. The inductor LD2 plays a role in current limiting to prevent excessive current impact at the initial stage of pre-charging; the capacitor CE4 is a filter capacitor used to stabilize the operation of the pre-charge circuit; the diode D2 serves as a freewheeling diode to provide a freewheeling path for the inductor when the switching transistor Q3 is turned off, preventing excessive reverse voltage from being generated on the inductor.

[0048] The inductor LD2 is a differential-mode inductor, and its function is to avoid large inrush currents when the PV circuit input is connected to the PV panel. By using the combination of a differential-mode inductor and a constant-current buck circuit, transient current impact can be effectively suppressed, and reliability and safety can be improved.

[0049] Taking the PV power supply module 310 as an example, in the voltage conversion unit 313, the control module 100 forms a Buck converter circuit by controlling the on-off timing of the first switching transistor Q1 and the second switching transistor Q2 to achieve the voltage conversion function. Specifically, when the pre-charge module 200 pre-charges the capacitor CE3, the pre-charge voltage pre-charges the first energy storage unit through the first switching transistor Q1 and the first inductor LD1. By adjusting the conduction time and frequency of the first switching transistor Q1 and the second switching transistor Q2, the pre-charge voltage of the first energy storage unit can be accurately controlled to keep it within a preset difference range from the voltage of the PV input source.

[0050] The detailed working process of the entire pre-charge process is as follows: When there is an input in PV input 1 or PV input 2, that is, when the input voltage is detected at PV1_IN+ or PV2_IN+, the control module controls the switching transistor Q3 to act, and the constant-current buck circuit composed of the inductor LD3, the capacitor CE4, the switching transistor Q3, and the diode D2 starts to work, converts the input voltage and outputs it to charge the capacitor CE5, the capacitor CE3, and the capacitor CE8.

[0051] Since the constant-current buck circuit will draw a certain amount of current from the PV input source, the PV open-circuit voltage will be pulled down. At this time, the control module 100 can judge whether the PV is a weak PV by measuring the PV voltage value at this time. If the measured voltage is lower than the preset threshold, it is determined to be in a weak PV state. At this time, the relays RLY1 and RLY2 can be selected not to be closed to avoid frequent switching operations caused by weak light.

[0052] Meanwhile, for the first photovoltaic power supply module 310, the control module 100 controls the first switching transistor Q1, the second switching transistor Q2, and the first inductor LD1 to form a buck circuit with reverse input to work, charging the PV input electrolytic capacitors of the capacitors CE1 and CE2. That is to say, PV1_IN+ charges the capacitors CE1 and CE2 through the inductor LD2, the switching transistor Q3, the inductor LD3, the switching transistor Q1, and the inductor LD1.

[0053] When the voltages at both ends of the capacitors CE1 and CE2 are close to the input voltage at the front end of the relay RLY1, the control module 100 turns on the relay RLY1. Since the input and output voltages are already close, no huge spike current will be generated, avoiding the risk of arcing or damaging devices, and successfully realizing the pre-charge function.

[0054] Similarly, for the second photovoltaic power supply module 320, the control module 100 controls the first switching transistor Q4, the second switching transistor Q5, and the first inductor LD4 to form a buck circuit with reverse input to work, charging the PV input electrolytic capacitors of the capacitors CE6 and CE7. That is to say, PV2_IN+ charges the capacitors CE6 and CE7 through the inductor LD2, the switching transistor Q3, the inductor LD3, the switching transistor Q1, and the inductor LD1.

[0055] When the voltages at both ends of the capacitors CE6 and CE7 are close to the input voltage at the front end of the relay RLY2, the control module 100 turns on the relay RLY2. Since the input and output voltages are already close, no huge spike current will be generated, avoiding the risk of arcing or damaging devices, and successfully realizing the pre-charge function.

[0056] It should be noted that the multi-channel photovoltaic parallel pre-charge circuit provided by the embodiment of the present application is not limited to a plurality of photovoltaic power supply modules. When applied to a scenario with only one photovoltaic input source, the circuit schematic diagram of the multi-channel photovoltaic parallel pre-charge circuit is as Figure 3 shown.

[0057] Referring to Figure 3 shown, according to the multi-channel photovoltaic parallel pre-charge circuit provided by this embodiment, the pre-charge module 200 includes a protection diode DS1, an inductor LD2, an inductor LD3, a capacitor CE4, a switching transistor Q3, a diode D2, and a capacitor CE5.

[0058] The switching unit 311 includes a relay RLY1, the first energy storage unit 312 includes capacitors CE1 and CE2, the voltage conversion unit 313 includes a first inductor LD1, a first switching transistor Q1, and a second switching transistor Q2, and the second energy storage unit 314 includes a capacitor CE3.

[0059] The anode of protection diode DS1 is connected to PV input 1, the cathode of protection diode DS1 is connected to the first end of inductor LD2, the second end of inductor LD2 is connected to the first end of capacitor CE4 and the drain of switch Q3, the source of switch Q3 is connected to the cathode of diode D2 and the first end of inductor LD3, the second end of inductor LD3 is connected to the first end of capacitor CE5 and the third pin of relay RLY1, the gate of switch Q3 is connected to control module 100, and the second ends of capacitor CE4, capacitor CE5 and the anode of diode D2 are connected to the reference ground BAT_GND.

[0060] The first pin and the second pin of relay RLY1 are connected to control module 100, the fourth pin of relay RLY1 is connected to PV input 1, the third pin of relay RLY1 is connected to the first end of the first inductor LD1, the first end of capacitor CE1 and the first end of capacitor CE2, the second end of the first inductor LD1 is connected to the drain of the second switch Q2 and the source of the first switch Q1, the drain of the first switch Q1 is connected to the first end of capacitor CE3, the second ends of capacitor CE1, capacitor CE2, capacitor CE3 and the source of the second switch Q2 are connected to the reference ground BAT_GND, and the gates of the first switch Q1 and the second switch Q2 are connected to control module 100.

[0061] When there is an input at PV input 1, that is, when PV1_IN+ detects an input voltage, the control module controls the operation of switch Q3, and the constant-current buck circuit composed of inductor LD3, capacitor CE4, switch Q3 and diode D2 starts to work, transforms the input voltage and outputs it to charge capacitor CE1, capacitor CE2 and capacitor CE3.

[0062] Since the constant-current buck circuit will draw a certain current from the photovoltaic input source, the PV open-circuit voltage will be pulled down. At this time, the control module 100 can judge whether the PV is a weak photovoltaic by measuring the PV voltage value at this time. If the measured voltage is lower than the preset threshold, it is determined to be in the weak photovoltaic state. At this time, it is possible to choose not to close relay RLY1 and relay RLY2 to avoid frequent switching operations caused by low light.

[0063] When the voltages across capacitor CE1, capacitor CE2 and capacitor CE5 are close to the PV1_IN+ voltage, the control module 100 turns on relay RLY1. Since the input and output voltages are already close, no huge spike current will be generated, avoiding the risk of arcing or damaging devices and successfully realizing the pre-charge function.

[0064] Different from the prior art, the multi-channel photovoltaic parallel pre-charge circuit provided by this embodiment realizes the parallel connection of multi-channel photovoltaic inputs, reduces the number of components used, lowers the overall cost of the circuit, and improves the economy. This circuit is flexible and can be adjusted according to various requirements. It is a reliable pre-charge circuit and weak photovoltaic detection circuit, with fewer circuit components used and a lower overall circuit cost, offering high cost performance.

[0065] Based on the multi-channel photovoltaic parallel pre-charge circuit provided by the above embodiment, the embodiment of the present application also provides an energy storage power supply, which includes the multi-channel photovoltaic parallel pre-charge circuit provided by any one of the above embodiments.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other variations in different aspects of the present application as described above. For the sake of brevity, they are not provided in detail; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A multi-channel photovoltaic parallel pre-charging circuit, characterized in that: include: Multiple photovoltaic power supply modules, pre-charging modules and control modules, wherein each photovoltaic power supply module comprises a switch unit, a first energy storage unit, a voltage conversion unit and a second energy storage unit connected in sequence; The input end of the switch unit is also used to connect with the pre-charging module and a photovoltaic input source, the pre-charging module is also connected with each of the second energy storage units, and the control module is respectively connected with the switch unit and the pre-charging module; The control module is used to control the operation of the pre-charging module when the photovoltaic power supply module is pre-charging, so that the pre-charging voltage output by the pre-charging module pre-charges the second energy storage unit and pre-charges the first energy storage unit through the voltage conversion unit; as well as When the photovoltaic power supply module supplies power normally, the switch unit is controlled to be turned on so that the electric energy of the photovoltaic input source sequentially passes through the switch unit, the first energy storage unit, the voltage conversion unit and the second energy storage unit to supply power to the subsequent stage.

2. The circuit according to claim 1, characterized in that The control module is used to control the pre-charging module to work and control the switch unit to disconnect when the photovoltaic power supply module is pre-charging; and When the multi-channel photovoltaic power supply module supplies power normally, the switch unit is controlled to be turned on and the pre-charging module is controlled to stop working.

3. The circuit according to claim 1, characterized in that For each photovoltaic power supply module, the voltage conversion unit is used to convert the pre-charging voltage output by the pre-charging module to a preset voltage when the photovoltaic power supply module is pre-charging, so as to pre-charge the first energy storage unit; wherein the difference between the preset voltage and the voltage of the photovoltaic input source to which the photovoltaic power supply module is connected is within a first preset range.

4. The circuit according to claim 1, characterized in that The control module is also used to determine whether the corresponding photovoltaic input source is in a weak voltage state according to the voltage of the photovoltaic input source connected to each photovoltaic power supply module after the pre-charging module is working.

5. The circuit according to any one of claims 1 to 4, characterized in that: The pre-charging module is a constant current pre-charging module.

6. The circuit according to claim 4, characterized in that The pre-charge module includes a plurality of protection diodes, an inductor LD2, an inductor LD3, a capacitor CE4, a switch tube Q3, a diode D2 and a capacitor CE5. The anode of each protection diode is connected to the input end of the switch unit of each photovoltaic power supply module, the cathode of each protection diode is connected to the first end of the inductor LD2, the second end of the inductor LD2 is connected to the first end of the capacitor CE4 and the drain of the switch tube Q3, the source of the switch tube Q3 is connected to the cathode of the diode D2 and the first end of the inductor LD3, the second end of the inductor LD3 is connected to the first end of the capacitor CE5 and the second energy storage unit of each photovoltaic power supply module, the gate of the switch tube Q3 is connected to the control module, and the second end of the capacitor CE4, the second end of the capacitor CE5 and the anode of the diode D2 are connected to the reference ground.

7. The circuit according to claim 6, characterized in that The multiple protection diodes are all Schottky diodes.

8. The circuit according to any one of claims 1 to 4, characterized in that: The first energy storage unit and the second energy storage unit are both energy storage capacitors.

9. The circuit according to any one of claims 1 to 4, characterized in that: The voltage conversion unit includes a first inductor, a first switch tube and a second switch tube. The first end of the first inductor is connected to the first energy storage unit and the output end of the switch unit, the second end of the first inductor is connected to the drain of the second switch tube and the source of the first switch tube, the drain of the first switch tube is connected to the second energy storage unit and the output end of the pre-charging module, the source of the second switch tube is connected to the reference ground, and the gate of the first switch tube and the gate of the second switch tube are connected to the control module.

10. An energy storage power supply, characterized in that: include: A multi-channel photovoltaic parallel pre-charging circuit as described in any one of claims 1 to 9.

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