Black-start and on-off circuit of optical storage and charging all-in-one machine

Abstract

The invention provides a black-start and on-off circuit for an optical storage and charging all-in-one machine. The system comprises a photovoltaic device, an energy storage device, a power grid access device, a control device and a bus capacitor, the bus capacitor is simultaneously connected with the photovoltaic device, the energy storage device and the power grid access device; the energy storage device comprises a DCDC conversion module and a battery switch module, the DCDC conversion module comprises an input capacitor, a first switch tube, a first diode connected with the first switch tube in parallel, a second switch tube and a second diode connected with the second switch tube in parallel, and the first end of the input capacitor is connected with the battery switch module. A common connection point of the first switch tube and the second switch tube is connected with a first end of the input capacitor; the battery switch module comprises a starting switch; the control device comprises a main controller; and when the photovoltaic device works and the alternating current power grid has no power, the main controller is used for controlling the photovoltaic device to charge the bus capacitor, controlling the second switching tube to be conducted to charge the input capacitor after the bus capacitor is fully charged, and controlling the starting switch to be closed after the input capacitor is fully charged.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a black start and power on / off circuit for a photovoltaic storage and charging integrated machine. Background Art

[0002] The photovoltaic storage and charging integrated device is a comprehensive device that integrates photovoltaic power generation, energy storage and charging functions, and is mainly used in smart grids, microgrids, etc. Existing photovoltaic storage and charging integrated devices have limitations in battery soft start. For example, some achieve battery soft start by connecting a relay in series with a resistor, but cannot achieve black start when the entire system is off the grid; some achieve black start by connecting an external manual switch in series with a resistor, and after the control system is powered on and initialized, the voltage difference before and after the DC main contactor is determined to close the DC main contactor, but the auxiliary source continues to consume energy during the control system initialization, resulting in the need to continuously press the external manual switch during the initialization time, resulting in a poor user experience. In addition, when the DC main contactor is closed (i.e., turned on) after the AC soft start, the solution has an impact current in the capacitor, which is easy to damage the device. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, the purpose of the present invention is to propose a black start and power on / off circuit for a photovoltaic storage and charging integrated device to solve the problem that the impact current during startup may damage the device.

[0005] To achieve the above-mentioned purpose, the present invention proposes a black start and switch circuit of a photovoltaic storage and charging integrated machine, comprising a photovoltaic device, an energy storage device, a grid access device, a control device and a bus capacitor; the bus capacitor is simultaneously connected to the output end of the photovoltaic device, the output end of the energy storage device and the machine side of the grid access device, and the grid side of the grid access device is connected to the AC grid; the energy storage device comprises a DCDC conversion module, a battery switch module and a battery module, the DCDC conversion module comprises an input capacitor, a first switch tube, a first diode connected in parallel with the first switch tube, a second switch tube, and a second diode connected in parallel with the second switch tube, the first end of the input capacitor is connected to the positive electrode of the battery module through the battery switch module, the second end of the input capacitor is connected to the negative electrode of the battery module, the common connection point of the first switch tube and the second switch tube is connected to the first end of the input capacitor, the anode of the first diode and the cathode of the second diode constitute the output end of the energy storage device, the battery switch module comprises a first branch and a second branch connected in parallel, the first branch comprises a first soft start resistor and a black start switch connected in series, and the second branch comprises a start switch; the control device comprises a main controller;

[0006] When the photovoltaic device is working and the AC power grid is out of power, the main controller is used to control the photovoltaic device to charge the bus capacitor, control the second switch tube to turn on to charge the input capacitor after the bus capacitor is full, and control the closing of the start switch after the input capacitor is full.

[0007] In the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided in the present invention, the grid access device includes an inverter and three switch groups. The three phases of the AC grid are connected to the inverter via corresponding switch groups respectively. Each switch group includes a second soft-start resistor, a first switch, a second switch and a third switch. The first switch is connected in series with the second switch, and the third switch is connected in series with the second soft-start resistor and then in parallel with the second switch.

[0008] In the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided by the present invention, when the AC power grid is powered, the main controller is also used to control the first switch and the third switch in each switch group to close so as to charge the bus capacitor through the second soft start resistor, and after the bus capacitor is fully charged, control the second switch in each switch group to close and control the third switch to disconnect to complete the AC soft start, and after the AC soft start is completed, control the second switch tube to turn on to charge the input capacitor, and control the closing of the start switch after the input capacitor is fully charged.

[0009] In the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided by the present invention, the control device also includes a start switch control circuit. When the photovoltaic device is not working and the AC power grid has no power, the start switch control circuit is used to monitor the voltage difference between the two ends of the first branch when the black start switch is closed, so as to control the closing of the start switch when the voltage difference meets the requirement.

[0010] In the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided by the present invention, the start switch control circuit includes an operational amplifier, a comparator, a first voltage divider resistor, a second voltage divider resistor and a first protection resistor. The two input terminals of the operational amplifier are respectively connected to the two ends of the first branch, the output terminal of the operational amplifier is connected to the negative input terminal of the comparator, the common connection point of the first voltage divider resistor and the second voltage divider resistor is connected to the positive input terminal of the comparator, and the output terminal of the comparator is connected to the control terminal of the start switch via the first protection resistor.

[0011] In the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided by the present invention, the start switch control circuit also includes a third switch tube, the control end of the third switch tube is connected to the main controller, and the output end of the third switch tube is connected to the output end of the comparator.

[0012] In the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided by the present invention, when a fault occurs or power off and shutdown is required, the main controller transmits a high level to the control end of the third switch tube to control the start switch to be disconnected.

[0013] In the black start and on / off circuit of the integrated photovoltaic storage and charging device provided by the present invention, the starting switch adopts a contactor.

[0014] In the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided by the present invention, the first switch, the second switch and the third switch are relays.

[0015] In the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided by the present invention, the first switch tube and the second switch tube are MOS tubes, and the third switch tube is a triode.

[0016] The black start and on / off circuit of the photovoltaic storage and charging integrated machine provided by the present invention comprises a photovoltaic device, an energy storage device, a grid access device, a control device and a bus capacitor; the bus capacitor is simultaneously connected to the output end of the photovoltaic device, the output end of the energy storage device and the machine side of the grid access device, and the grid side of the grid access device is connected to the AC grid; the energy storage device comprises a DCDC conversion module, a battery switch module and a battery module, the DCDC conversion module comprises an input capacitor, a first switch tube, a first diode connected in parallel with the first switch tube, a second switch tube, and a second diode connected in parallel with the second switch tube, the first end of the input capacitor is connected to the positive electrode of the battery module via the battery switch module, and the input The second end of the capacitor is connected to the negative electrode of the battery module, the common connection point of the first switch tube and the second switch tube is connected to the first end of the input capacitor, the anode of the first diode and the cathode of the second diode constitute the output end of the energy storage device, the battery switch module includes a first branch and a second branch connected in parallel, the first branch includes a first soft start resistor and a black start switch connected in series, and the second branch includes a start switch; the control device includes a main controller; when the photovoltaic device is working and the AC power grid is out of power, the main controller is used to control the photovoltaic device to charge the bus capacitor, control the second switch tube to conduct to charge the input capacitor after the bus capacitor is full, and control the closing of the start switch after the input capacitor is full. In this case, the photovoltaic device is used to charge the bus capacitor until the bus capacitor is full to complete the soft start, and then the second switch tube in the DCDC conversion module is controlled to conduct to charge the input capacitor, and the start switch is controlled to close after the input capacitor is full, avoiding the generation of impact current by directly closing the switch connected to the battery module after the soft start is completed as in the prior art, thereby solving the problem that the impact current is easy to damage the device when starting.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0019] Figure 1 A block diagram of a black start and power on / off circuit of a photovoltaic storage and charging integrated device provided in an embodiment of the present invention;

[0020] Figure 2 A partial circuit diagram of a black start and power on / off circuit of a photovoltaic storage and charging integrated device provided in an embodiment of the present invention;

[0021] Figure 3 A circuit diagram of a startup switch control circuit provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the embodiments of the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the embodiments of the present invention as detailed in the appended claims.

[0023] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. It should also be understood that the term "and / or" used in the present invention refers to and includes any or all possible combinations of one or more associated listed items.

[0025] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0026] The present invention proposes a black start and power on / off circuit for a photovoltaic storage and charging integrated machine to solve the problem that the impact current during startup is likely to damage the device and the problem that the black start time is too long.

[0027] In an embodiment of the present invention, Figure 1 A block diagram of a black start and power on / off circuit for a photovoltaic storage and charging integrated device provided in an embodiment of the present invention. Figure 2 This is a partial circuit diagram of the black start and power on / off circuit of the integrated photovoltaic storage and charging device provided in an embodiment of the present invention. Figure 1 As shown, the black start and switch circuit of the photovoltaic storage and charging integrated machine includes a photovoltaic device, an energy storage device, a grid access device, a control device and a bus capacitor. Among them, the bus capacitor is connected to the output end of the photovoltaic device, the output end of the energy storage device and the machine side of the grid access device at the same time, and the grid side of the grid access device is connected to the AC grid. The control device is connected to the photovoltaic device, the energy storage device and the grid access device at the same time.

[0028] In this embodiment, the energy storage device includes a DCDC conversion module, a battery switch module and a battery module. The positive electrode of the input end of the DCDC conversion module is connected to the positive electrode of the battery module through the battery switch module, and the negative electrode of the input end of the DCDC conversion module is connected to the negative electrode of the battery module. The output end of the DCDC conversion module is the output end of the energy storage device.

[0029] In this embodiment, the DCDC conversion module includes an input capacitor, a first switch tube, a first diode connected in parallel with the first switch tube, a second switch tube, and a second diode connected in parallel with the second switch tube. The first end of the input capacitor is connected to the positive electrode of the battery module BAT through the battery switch module, and the second end of the input capacitor is connected to the negative electrode of the battery module BAT. The common connection point of the first switch tube and the second switch tube is connected to the first end of the input capacitor. The DCDC conversion module may also include an input inductor, the first end of the input inductor is connected to the first end of the input capacitor, and the second end of the input inductor is connected to the common connection point of the first switch tube and the second switch tube. The first end of the input capacitor is the positive input terminal of the DCDC conversion module, and the second end of the input capacitor is the negative input terminal of the DCDC conversion module. The anode of the first diode and the cathode of the second diode are the output terminals of the DCDC conversion module, that is, the anode of the first diode and the cathode of the second diode constitute the output terminal of the energy storage device.

[0030] Types of the first switch tube and the second switch tube include but are not limited to bipolar junction transistor (Bipolar Junction Transistor, BJT), gate turn-off thyristor (GTO), insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), integrated gate commutated thyristor (Integrated Gate Commuted Transistor, IGCT) and metal oxide semiconductor field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET, MOS), etc.

[0031] For example, the first switch tube and the second switch tube are both MOS tubes. Figure 2 As shown, the DCDC conversion module includes an input capacitor C1, an input inductor L1, a first MOS transistor Q1, a first diode D1, a second MOS transistor Q2, and a second diode D2, wherein the first diode D1 is connected in parallel with the first MOS transistor Q1 in an anti-parallel manner, and the second diode D2 is connected in parallel with the second MOS transistor Q2 in an anti-parallel manner. The anode of the first diode D1 and the cathode of the second diode D2 are connected to both ends of the bus capacitor C2.

[0032] In this embodiment, the battery switch module includes a first branch and a second branch connected in parallel, the first branch includes a first soft start resistor and a black start switch connected in series, and the second branch includes a start switch. The black start switch can be a manual switch, and the start switch can be a contactor.

[0033] Take the example of a black start switch using a manual switch and a start switch using a contactor. Figure 2 As shown, the battery switch module includes a first soft-start resistor R1, a manual switch S1, and a contactor S2. The first soft-start resistor R1 is connected in series with the manual switch S1 and then connected in parallel with the contactor S2.

[0034] In this embodiment, the on and off of the start switch is controlled by the control device.

[0035] In this embodiment, the photovoltaic device is used to generate electricity using solar energy. The photovoltaic device includes a photovoltaic module PV and a transformer module. The transformer module is used to adjust the output voltage of the photovoltaic module. Figure 2As shown, the transformer module includes a capacitor C3, an inductor L2, a MOS tube Q3, a diode D3, and a diode D4, wherein the MOS tube Q3 and the diode D3 are connected in parallel in an anti-parallel manner. The first end of the capacitor C3 is respectively connected to the output positive electrode of the photovoltaic module PV and the first end of the inductor L2, the second end of the capacitor C3 is respectively connected to the output negative electrode of the photovoltaic module PV and the anode of the diode D3, the anode of the diode D3 and the cathode of the diode D4 constitute the output end of the photovoltaic device, and the anode of the diode D3 and the cathode of the diode D4 are connected to the two ends of the bus capacitor C2.

[0036] In this embodiment, the grid access device includes an inverter and three switch groups. The three phases of the AC grid are connected to the inverter via the corresponding switch groups. Each switch group includes a second soft-start resistor, a first switch, a second switch, and a third switch. The first switch is connected in series with the second switch, and the third switch is connected in series with the second soft-start resistor and then in parallel with the second switch. The first switch, the second switch, and the third switch can be relays.

[0037] For example, the first switch, the second switch and the third switch are all relays. Figure 2 As shown, the grid access device includes an inverter INV and three switch groups, the three switch groups are A-phase switch group, B-phase switch group, and C-phase switch group, the A-phase switch group includes A-phase first relay SA1, A-phase second relay SA2, A-phase third relay SA3 and A-phase second soft-start resistor R2, the B-phase switch group includes B-phase first relay SB1, B-phase second relay SB2, B-phase third relay SB3 and B-phase second soft-start resistor R3, and the C-phase switch group includes C-phase first relay SC1, C-phase second relay SC2, C-phase third relay SC3 and C-phase second soft-start resistor R4. The first end of the A-phase first relay SA1, the first end of the B-phase first relay SB1, and the first end of the C-phase first relay SC1 constitute the grid side of the grid access device, and are respectively connected to the ABC three-phases of the AC grid. The second end of the A-phase first relay SA1, the second end of the B-phase first relay SB1, and the second end of the C-phase first relay SC1 are connected to the first end of the inverter INV via the A-phase second relay SA2, the B-phase second relay SB2, and the C-phase second relay SC2 respectively. The second end of the inverter INV is the machine side of the grid access device, and the second end of the inverter INV is connected to the two ends of the bus capacitor C2.

[0038] In this embodiment, the black start and power on / off circuit of the photovoltaic storage and charging integrated device may further include an auxiliary source device, which is used to power other electronic components in the black start and power on / off circuit of the photovoltaic storage and charging integrated device. Other components include but are not limited to inverter INV, contactor, etc. The auxiliary source device includes a DC auxiliary source and an AC auxiliary source, the DC auxiliary source is used to convert DC power into the DC voltage required by the electronic components, and the AC auxiliary source is used to convert AC power into the DC voltage required by the electronic components.

[0039] like Figure 2 As shown, the auxiliary source device includes a DC auxiliary source and an AC auxiliary source. The DC auxiliary source input end of the auxiliary source device is connected to the busbar on the inverter INV side, the AC auxiliary source input end of the auxiliary source device is connected to the AC grid, and the output end of the auxiliary source device (i.e., the DC auxiliary source or the AC auxiliary source output end) is connected to the inverter INV. When the auxiliary source device is in operation, it supplies power to the inverter INV. It should be noted that Figure 2 Only the connection between the auxiliary source device and the inverter INV is shown, and the connection between the auxiliary source device and other components is not shown.

[0040] In this embodiment, the control device includes a main controller which may be a MCU (Microcontroller Unit).

[0041] In this embodiment, the control device also includes a start switch control circuit. The start switch control circuit includes an operational amplifier, a comparator, a first voltage-dividing resistor, a second voltage-dividing resistor and a first protection resistor, the two input ends of the operational amplifier are respectively connected to the two ends of the first branch, the output end of the operational amplifier is connected to the negative input end of the comparator, the common connection point of the first voltage-dividing resistor and the second voltage-dividing resistor is connected to the positive input end of the comparator, and the output end of the comparator is connected to the control end of the start switch via the first protection resistor. The start switch control circuit also includes a third switch tube, the control end of the third switch tube is connected to the main controller, and the output end of the third switch tube is connected to the output end of the comparator.

[0042] Taking the case where the third switch tube uses a triode as an example, Figure 3 FIG. 1 is a circuit diagram of a startup switch control circuit provided by an embodiment of the present invention. Figure 3 As shown, the start switch control circuit includes an operational amplifier U1, a comparator U2, a first voltage-dividing resistor R5, a second voltage-dividing resistor R6 and a first protection resistor R8. The two input terminals of the operational amplifier U1 are respectively connected to the two ends of the first branch (UA and UB are the voltages at the two ends of the first branch), the output terminal of the operational amplifier U1 is connected to the negative input terminal of the comparator U2, the common connection point of the first voltage-dividing resistor R5 and the second voltage-dividing resistor R6 is connected to the positive input terminal of the comparator U2, and the output terminal of the comparator U2 is connected to the control terminal of the start switch via the first protection resistor R8. Figure 3As shown, the start switch control circuit also includes a transistor Q4, a base resistor R9, a pull-down resistor R10 and a collector resistor R7. Among them, the emitter of the transistor Q4 is grounded (GND), the base of the transistor Q4 is connected to the main controller through the base resistor R9, and receives the enable signal S2_EN_DSP output by the main controller, and the collector of the transistor Q4 is connected to the output end of the comparator U2. The output end of the comparator U2 outputs the control signal S2_EN.

[0043] In this embodiment, when the photovoltaic device is working and the AC power grid is out of power, the main controller is used to control the photovoltaic device to charge the bus capacitor, and after the bus capacitor is full, control the second switch tube to turn on to charge the input capacitor, and after the input capacitor is full, control the closing of the start switch.

[0044] In this embodiment, when the AC power grid is powered, the main controller is also used to control the first switch and the third switch in each switch group to close to charge the bus capacitor through the second soft-start resistor, and after the bus capacitor is fully charged, control the second switch in each switch group to close and control the third switch to disconnect to complete the AC soft start, and after the AC soft start is completed, control the second switch tube to turn on to charge the input capacitor, and control the closing of the start switch after the input capacitor is fully charged.

[0045] In this embodiment, when the photovoltaic device is not working and the AC grid is without power, the start switch control circuit is used to monitor the voltage difference between the two ends of the first branch when the black start switch is closed, so as to control the start switch to close when the voltage difference meets the requirement. When a fault occurs or the power needs to be turned off, the main controller transmits a high level to the control end of the third switch tube to control the start switch to open.

[0046] Specifically, taking the main controller using MCU as an example, combined with Figure 2 and Figure 3 The specific operation process of the black start and power on / off circuit of the photovoltaic storage and charging integrated device is as follows:

[0047] 1) When the AC grid is powered, the AC auxiliary source works, and the main control MCU closes the first relay SA1 of phase A, the first relay SB1 of phase B, the first relay SC1 of phase C, the third relay SA3 of phase A, the third relay SB3 of phase B, and the third relay SC3 of phase C, and charges the bus capacitor C2 through the second soft-start resistor R2 of phase A, the second soft-start resistor R3 of phase B, and the second soft-start resistor R4 of phase C. After charging is completed, the main control MCU closes the second relay SA2 of phase A, the second relay SB2 of phase B, and the second relay SC2 of phase C, and disconnects the third relay SA3 of phase A, the third relay SB3 of phase B, and the third relay SC3 of phase C, and the AC soft start is completed. In order to avoid the impact current on the input capacitor C1 when the main control MCU closes the contactor S2, after the AC soft start is completed, the main control MCU controls the second MOS tube Q2 to conduct the pulse to charge the input capacitor C1. After the input capacitor C1 is fully charged, the contactor S2 is closed, and the entire system is powered on.

[0048] 2) When the AC grid has no electricity and the PV has electricity, the DC auxiliary source works, and the main control MCU controls the PV to boost the voltage and then charge the bus capacitor C2. When the bus capacitor C2 is fully charged, the DC soft start is completed. In order to avoid the impact current on the input capacitor C1 when the main control MCU closes the contactor S2, after the DC soft start is completed, the main control MCU controls the second MOS tube Q2 to pulse conduct to charge the input capacitor C1. After the input capacitor C1 is fully charged, the main control MCU closes the contactor S2, and the whole system is powered on.

[0049] 3) When the AC grid has no electricity and the PV has no electricity, the AC auxiliary source and the DC auxiliary source do not work, the manual switch S1 is closed, and the battery module BAT charges the input capacitor C1 and the bus capacitor C2 through the first soft-start resistor R1. During the capacitor charging process, the DC auxiliary source starts to work, and the operational amplifier U1 calculates the difference between the voltages at points A and B of the first branch. When the difference voltage is less than the set value of 30V, the control signal S2_EN output by the comparator U2 is high level. At this time, the control signal is used as the contactor S2 pull-in signal, so that the contactor S2 is closed. After the contactor S2 is closed, the manual switch S1 can be released, the battery soft start is completed, the entire system starts to work, and the black start is completed. When the system fails or needs to be powered off, the main control MCU sends a high-level enable signal S2_EN_MCU, the transistor Q4 is turned on, the control signal S2_EN is pulled low, and the contactor S2 is disconnected, that is, the hardware pull-in and software disconnection function of the contactor S2 is completed. In this case, after the battery soft start is completed, the contactor S2 is controlled to be energized through the hardware circuit. The manual switch S1 can be released to complete the black start without waiting for the main MCU to initialize. This avoids the problem of the main MCU controlling the contactor S2 to be energized as in the prior art. The manual switch S1 needs to be kept closed during the contactor S2 energization process until the soft start and initialization are completed and the black start is completed, which causes the user to wait too long for the black start.

[0050] The black start and power on / off circuit of the photovoltaic storage and charging integrated machine in the embodiment of the present invention includes a photovoltaic device, an energy storage device, a grid access device, a control device and a bus capacitor; the bus capacitor is connected to the output end of the photovoltaic device, the output end of the energy storage device and the machine side of the grid access device at the same time, and the grid side of the grid access device is connected to the AC grid; the energy storage device includes a DCDC conversion module, a battery switch module and a battery module, the DCDC conversion module includes an input capacitor, a first switch tube, a first diode connected in parallel with the first switch tube, a second switch tube, and a second diode connected in parallel with the second switch tube, the first end of the input capacitor is connected to the positive electrode of the battery module via the battery switch module, and the input The second end of the input capacitor is connected to the negative electrode of the battery module, the common connection point of the first switch tube and the second switch tube is connected to the first end of the input capacitor, the anode of the first diode and the cathode of the second diode constitute the output end of the energy storage device, the battery switch module includes a first branch and a second branch connected in parallel, the first branch includes a first soft start resistor and a black start switch connected in series, and the second branch includes a start switch; the control device includes a main controller; when the photovoltaic device is working and the AC power grid is out of power, the main controller is used to control the photovoltaic device to charge the bus capacitor, control the second switch tube to conduct to charge the input capacitor after the bus capacitor is full, and control the closing of the start switch after the input capacitor is full. In this case, the photovoltaic device is used to charge the bus capacitor until the bus capacitor is full to complete the soft start, and then the second switch tube in the DCDC conversion module is controlled to conduct to charge the input capacitor, and the start switch is controlled to close after the input capacitor is full, avoiding the generation of impact current by directly closing the switch connected to the battery module after the soft start is completed as in the prior art, thereby solving the problem that the impact current is easy to damage the device when starting.

[0051] The advantages of the present invention include: 1) when the AC power grid has power, the bus capacitor is charged to realize soft start, and after the soft start is completed, the Q2 pulse is controlled to be turned on to charge the input capacitor C1, thereby avoiding the impact current when the contactor S2 is attracted; 2) when the AC power grid has no power but the PV has power, the PV charges the bus capacitor C2 to realize soft start, and after the charging is completed, the Q2 pulse is controlled to be turned on to charge the input capacitor C1, thereby avoiding the impact current when the contactor S2 is attracted; 3) when the AC power grid has no power and the PV has no power, the manual switch S1 is closed to charge the input capacitor C1 and the bus capacitor C2 to realize soft start, and the contactor S2 is attracted by judging through the hardware circuit, which is independent of the main control MCU, avoids the waiting time for the main control MCU to initialize, and solves the problem of too long waiting time for the user's black start; 4) the contactor S2 realizes the hardware attraction and software disconnection functions.

[0052] The accompanying drawings show schematic diagrams of structures according to embodiments disclosed in the present invention. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0053] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and the present invention is not limited here.

[0054] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A black start and power on / off circuit for a photovoltaic storage and charging integrated device, characterized in that: It includes a photovoltaic device, an energy storage device, a grid access device, a control device and a bus capacitor; the bus capacitor is connected to the output end of the photovoltaic device, the output end of the energy storage device and the machine side of the grid access device at the same time, and the grid side of the grid access device is connected to the AC grid; the energy storage device includes a DCDC conversion module, a battery switch module and a battery module, the DCDC conversion module includes an input capacitor, a first switch tube, a first diode connected in parallel with the first switch tube, a second switch tube, and a second diode connected in parallel with the second switch tube, the first end of the input capacitor is connected to the positive electrode of the battery module through the battery switch module, the second end of the input capacitor is connected to the negative electrode of the battery module, the common connection point of the first switch tube and the second switch tube is connected to the first end of the input capacitor, the anode of the first diode and the cathode of the second diode constitute the output end of the energy storage device, the battery switch module includes a first branch and a second branch connected in parallel, the first branch includes a first soft start resistor and a black start switch connected in series, and the second branch includes a start switch; the control device includes a main controller; When the photovoltaic device is working and the AC power grid is out of power, the main controller is used to control the photovoltaic device to charge the bus capacitor, control the second switch tube to turn on to charge the input capacitor after the bus capacitor is full, and control the closing of the start switch after the input capacitor is full.

2. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 1, characterized in that: The grid access device includes an inverter and three switch groups. The three phases of the AC grid are connected to the inverter via corresponding switch groups respectively. Each switch group includes a second soft-start resistor, a first switch, a second switch and a third switch. The first switch is connected in series with the second switch, and the third switch is connected in series with the second soft-start resistor and then in parallel with the second switch.

3. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 2, characterized in that: When the AC power grid has electricity, the main controller is also used to control the first switch and the third switch in each switch group to close so as to charge the bus capacitor through the second soft-start resistor, and after the bus capacitor is full, control the second switch in each switch group to close and control the third switch to disconnect to complete the AC soft start, and after the AC soft start is completed, control the second switch tube to turn on to charge the input capacitor, and control the closing of the start switch after the input capacitor is full.

4. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 1, characterized in that: The control device also includes a starting switch control circuit. When the photovoltaic device is not working and the AC power grid is without power, the starting switch control circuit is used to monitor the voltage difference between the two ends of the first branch when the black-start switch is closed, so as to control the starting switch to close when the voltage difference meets the requirements.

5. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 4, characterized in that: The startup switch control circuit includes an operational amplifier, a comparator, a first voltage-dividing resistor, a second voltage-dividing resistor and a first protection resistor. The two input terminals of the operational amplifier are respectively connected to the two ends of the first branch, the output terminal of the operational amplifier is connected to the negative input terminal of the comparator, the common connection point of the first voltage-dividing resistor and the second voltage-dividing resistor is connected to the positive input terminal of the comparator, and the output terminal of the comparator is connected to the control terminal of the startup switch via the first protection resistor.

6. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 5, characterized in that: The startup switch control circuit further includes a third switch tube, a control end of the third switch tube is connected to the main controller, and an output end of the third switch tube is connected to the output end of the comparator.

7. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 6, characterized in that: When a fault occurs or power-off is required, the main controller transmits a high level to the control end of the third switch tube to control the start switch to be disconnected.

8. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 1, characterized in that: The starting switch adopts a contactor.

9. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 2, characterized in that: The first switch, the second switch and the third switch are relays.

10. The black start and power on / off circuit of the integrated photovoltaic storage and charging device according to claim 6, characterized in that: The first switch tube and the second switch tube are MOS tubes, and the third switch tube is a triode.

Images