Power supply circuits, power conversion equipment and energy storage equipment

Abstract

The present application belongs to the field of power supply control technology, and provides a power supply circuit, a power conversion device and an energy storage device. A DC input circuit performs power conversion on the DC power input by a photovoltaic array, and outputs a rated voltage to a DC bus. An AC / DC conversion circuit converts the DC power on the DC bus into AC power, and then sends it to an AC device through an output interface circuit. When a first control circuit detects that the bus voltage of the DC bus drops from a first voltage value to a second voltage value, it sends a first control instruction to the DC / DC conversion circuit, switches the DC / DC conversion circuit from a current working state to a discharge state, and performs voltage conversion on the DC power output by a battery module according to a first preset conversion power, and then outputs it to the DC bus, so that the working state of the DC / DC conversion circuit can be quickly switched when the input power supply and the power consumption state of the AC device change.

Description

Technical Field

[0001] This application belongs to the field of power control technology, and in particular relates to a power supply circuit, power conversion device and energy storage device. Background Technology

[0002] In a power supply circuit composed of multiple subsystems, the output voltage may fluctuate because the power supply parameters provided by each subsystem may differ. This necessitates not only voltage conversion circuits but also power conversion control for each subsystem. For example, if one subsystem is an energy storage device operating as an uninterruptible power supply (UPS), the input source needs to be monitored to switch the energy storage device's battery modules to supply power or charge them based on the input power supply.

[0003] In related technologies, power supply circuits composed of multiple subsystems require power conversion and power supply switching control based on the input power and connected load. However, current methods for detecting various parameters and switching between hardware and software suffer from slow switching times, large power output fluctuations, increased losses in the power conversion circuit, and potential safety hazards to the electrical load. Summary of the Invention

[0004] To address the aforementioned technical problems, embodiments of this application provide a power supply circuit, a power conversion device, and an energy storage device, which can solve the problem of slow switching of the power supply's operating state when power consumption conditions change.

[0005] A first aspect of this application provides a power supply circuit, which includes an AC / DC conversion circuit, a DC / DC conversion circuit, a first control circuit, an output interface circuit, and a DC input circuit.

[0006] The input terminal of the output interface circuit is connected to the first terminal of the AC / DC conversion circuit, and the output terminal of the output interface circuit is used to connect to AC equipment; the second terminal of the AC / DC conversion circuit is connected to the first terminal of the DC / DC conversion circuit through a DC bus, and the second terminal of the DC / DC conversion circuit is used to connect to the battery module; the input terminal of the DC input circuit is connected to the photovoltaic array, and the output terminal of the DC input circuit is connected to the DC bus; the first control circuit is connected to both the DC bus and the DC / DC conversion circuit.

[0007] The DC input circuit is used to convert the DC power input from the photovoltaic array into power and output the rated voltage to the DC bus.

[0008] The AC / DC conversion circuit is used to convert the DC power on the DC bus into AC power and then send it to the AC device through the output interface circuit.

[0009] The DC / DC converter circuit is used to convert the DC power on the DC bus into voltage and then charge the battery module; it is also used to convert the DC power output from the battery module into voltage and then output it to the DC bus.

[0010] The first control circuit is used to send a first control command to the DC / DC conversion circuit when it detects that the bus voltage of the DC bus drops from a first voltage value to a second voltage value. The first control command is used to control the DC / DC conversion circuit to switch from the current working state to the discharge state, and to convert the DC power output by the battery module into voltage according to a first preset conversion power and then output it to the DC bus.

[0011] In one embodiment, the power supply circuit further includes a second control circuit connected to the AC / DC conversion circuit;

[0012] The second control circuit is used to send a first indication signal to the first control circuit when the AC / DC conversion circuit is in the discharge state after converting the DC power on the DC bus into AC power and sending it to the AC device through the output interface circuit;

[0013] The first control circuit is further configured to, upon receiving the first indication signal, send the first control command to the DC / DC conversion circuit when it detects that the bus voltage of the DC bus has dropped from a first voltage value to a second voltage value.

[0014] In one embodiment, the power supply circuit further includes a main control circuit;

[0015] The main control circuit is used to generate a second control command based on the power demand of the AC device and the input power of the DC input circuit, and send the second control command to the DC / DC conversion circuit. The second control command controls the conversion power of the DC / DC conversion circuit so that the sum of the conversion power of the DC / DC conversion circuit and the input power of the DC input circuit meets the power demand of the AC device.

[0016] In one embodiment, the power supply circuit further includes an AC input circuit and a switching circuit; the input terminal of the AC input circuit is used to connect to an AC power source, the output terminal of the AC input circuit is connected to a first terminal of the switching circuit, and the second terminal of the switching circuit is connected to the AC / DC conversion circuit and the output interface circuit respectively.

[0017] The main control circuit is also used to generate a first switch control signal when it detects that the input power of the DC input circuit is less than the required power of the AC device, and send the first switch control signal to the switch circuit. The first switch control signal is used to control the switch circuit to close so as to output the AC power provided by the AC power supply to the AC device.

[0018] In one embodiment, the main control circuit is further configured to generate a second switch control signal and a second control command when it detects that the input power of the DC input circuit is greater than the required power of the AC device, send the second switch control signal to the switch circuit, and send the second control command to the DC / DC conversion circuit. The second switch control signal is used to control the switch circuit to disconnect; the second control command is used to control the DC / DC conversion circuit to switch from the current operating state to the charging state, so as to convert the DC power on the DC bus into voltage and charge the battery module.

[0019] In one embodiment, the first control circuit is further configured to send the first switch control signal to the switch circuit and send a third control command to the DC / DC converter circuit when the bus voltage of the DC bus is detected to drop to a third voltage value. The third control command is used to control the DC / DC converter circuit to enter a standby state. The third voltage value is greater than the first voltage value.

[0020] In one embodiment, the main control circuit is further configured to send the third control command to the DC / DC conversion circuit when it detects that the input power of the DC input circuit is equal to the power demand of the AC device.

[0021] In one embodiment, the second control command is a pulse width modulation signal;

[0022] The main control circuit is also used to adjust the duty cycle and frequency of the second control command according to the conversion power of the DC / DC converter circuit, the input power of the DC input circuit, and the power requirement of the AC device, so that the sum of the conversion power of the DC / DC converter circuit and the input power of the DC input circuit meets the power requirement of the AC device.

[0023] A second aspect of this application also provides a power conversion device, the power conversion device including a power supply circuit as described in any of the above embodiments.

[0024] A third aspect of this application also provides an energy storage device, which includes a battery module and a power supply circuit as described in any of the above embodiments.

[0025] The beneficial effects of this application embodiment are as follows: By sequentially connecting the output interface circuit, AC / DC conversion circuit, DC bus, and DC / DC conversion circuit, the DC input circuit converts the DC power input from the photovoltaic array into power and outputs the rated voltage to the DC bus. The AC / DC conversion circuit converts the DC power on the DC bus into AC power and sends it to the AC device through the output interface circuit. When the first control circuit detects that the bus voltage of the DC bus drops from the first voltage value to the second voltage value, it sends a first control command to the DC / DC conversion circuit, switching the DC / DC conversion circuit from the current working state to the discharge state. The DC power output from the battery module is converted into voltage according to the first preset conversion power and then output to the DC bus. Thus, the working state of the DC / DC conversion circuit can be quickly switched when the power input and the power consumption state of the AC device change, meeting the power supply requirements of the power supply circuit to switch quickly when the power consumption state changes. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the power supply circuit provided in one embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the power supply circuit provided in another embodiment of this application;

[0028] Figure 3 This is a schematic diagram of the power supply circuit provided in another embodiment of this application;

[0029] Figure 4 This is a schematic diagram of the power supply circuit provided in another embodiment of this application;

[0030] Figure 5 This is a schematic diagram of the power supply circuit provided in another embodiment of this application;

[0031] Figure 6 This is a schematic diagram of the structure of a power conversion device provided in an embodiment of this application;

[0032] Figure 7 This is a schematic diagram of the structure of an energy storage device provided in an embodiment of this application;

[0033] Figure 8 This is a schematic diagram of a specific circuit of a battery module provided in one embodiment of this application. Detailed Implementation

[0034] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0035] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0036] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means one or more, unless otherwise explicitly specified.

[0038] In a power supply circuit composed of multiple subsystems, the output voltage of the power supply circuit may fluctuate because the power supply parameters provided by each subsystem may be different. In this case, not only voltage conversion circuits are needed, but also power conversion control for each subsystem is required. For example, when a photovoltaic maximum power point tracking (MPPT) circuit or a battery module is connected to a DC bus, the photovoltaic array outputs a voltage to the MPPT circuit after photoelectric conversion. The MPPT circuit then converts the input voltage of the photovoltaic array into power and outputs it to the load, other circuits, or batteries. However, when the photovoltaic array is under low light conditions (such as severe cloud cover or weak sunlight in the early morning or late evening), the photovoltaic array outputs a lower voltage. This lower voltage is sufficient to start the switching circuit and power conversion circuit, but the power conversion circuit suffers from significant losses, causing the input voltage of the photovoltaic array to drop further to an insufficient level to start the switching circuit or power conversion circuit. This results in the switching circuit disconnecting. After the switching circuit disconnects, the input voltage of the photovoltaic array recovers, restarting the switching circuit and power conversion circuit.

[0039] It is evident that in a power supply circuit composed of multiple subsystems, power conversion and power supply switching control are required based on the input power and connected load. However, currently, when detecting various parameters and switching between hardware and software, there are issues such as slow switching time, large power output fluctuations, increased power conversion circuit losses, and potential safety hazards to the electrical load.

[0040] To address the aforementioned technical problems, this application provides a power supply circuit, see [link to relevant documentation]. Figure 1 As shown, the power supply circuit includes an AC / DC conversion circuit 300, a DC / DC conversion circuit 400, a first control circuit 110, an output interface circuit 220, and a DC input circuit 210.

[0041] Specifically, the input terminal of the output interface circuit 220 is connected to the first terminal of the AC / DC converter circuit 300, and the output terminal of the output interface circuit 220 is used to connect AC equipment; the second terminal of the AC / DC converter circuit 300 is connected to the first terminal of the DC / DC converter circuit 400 through the DC bus 101, and the second terminal of the DC / DC converter circuit 400 is used to connect to the battery module 500; the input terminal of the DC input circuit 210 is connected to the photovoltaic array, and the output terminal of the DC input circuit 210 is connected to the DC bus 101; the first control circuit 110 is connected to the DC bus 101 and the DC / DC converter circuit 400 respectively.

[0042] In this embodiment, the DC input circuit 210 converts the DC power input from the photovoltaic array into power and outputs a rated voltage to the DC bus 101. The AC / DC conversion circuit 300 converts the DC power on the DC bus 101 into AC power and sends it to AC devices through the output interface circuit 220. The DC / DC conversion circuit 400 converts the DC power on the DC bus 101 into voltage and charges the battery module 500. In addition, the DC / DC conversion circuit 400 also converts the DC power output from the battery module 500 into voltage and outputs it to the DC bus 101. The first control circuit 110 sends a first control command to the DC / DC conversion circuit 400 when it detects that the bus voltage of the DC bus 101 drops from a first voltage value to a second voltage value. The first control command controls the DC / DC conversion circuit 400 to switch from the current operating state to the discharge state and converts the DC power output from the battery module 500 into voltage according to a first preset conversion power and outputs it to the DC bus 101.

[0043] In this embodiment, the DC input circuit 210, AC / DC conversion circuit 300, and DC / DC conversion circuit 400 are all connected to the DC bus 101. The photovoltaic array is connected to the DC bus 101 through the DC input circuit 210. The first control circuit 110 detects the bus voltage on the DC bus 101. When the bus voltage drops from the first voltage value to the second voltage value, it indicates that the output power of the photovoltaic array has decreased. The voltage of the output interface circuit 220 connected to the first terminal of the AC / DC conversion circuit 300 has decreased. At this time, the first control circuit 110 sends a first control command to the DC / DC conversion circuit 400. The first control command is used to control the DC / DC conversion circuit 400 to switch from the current working state to the discharge state, and to make the DC / DC conversion circuit 400 convert the DC power output by the battery module 500 according to the first preset conversion power and output it to the DC bus 101. Thus, the power demand of the AC equipment is met by quickly switching the working state of the DC / DC conversion circuit 400.

[0044] In one embodiment, the DC input circuit 210 can be an MPPT (Maximum Power Point Tracking) circuit. The electrical energy generated by the photovoltaic array after photoelectric conversion is tracked and boosted or bucked by the MPPT circuit before being input to the DC bus 101. It should be noted that the MPPT circuit is used to perform maximum power point tracking and buck / boost processing on the photovoltaic array. Because the voltage of the DC bus 101 is high, in order for the electrical energy output by the photovoltaic array to be connected to the DC bus 101, the MPPT circuit needs to perform either boost (the voltage output by the photovoltaic array is lower than the voltage of the DC bus 101) or buck (the voltage output by the photovoltaic array is higher than the bus voltage) processing after MPPT tracking of the photovoltaic array.

[0045] In one embodiment, the first control command may include at least one pulse width modulation signal, which is connected one-to-one with the control terminal of the switching transistor in the DC / DC converter circuit 400, thereby switching the DC / DC converter circuit 400 from the current working state to the discharge state by controlling the switching state of the switching transistor.

[0046] In a specific application embodiment, the conversion power of the DC / DC converter circuit 400 can be adjusted by regulating the duty cycle of the pulse width modulation signal. For example, when the first control circuit sends a first control command (at least one pulse width modulation signal) to the DC / DC converter circuit 400, the DC / DC converter circuit 400 converts the DC power output from the battery module 500 into voltage and outputs it to the DC bus 101 according to the first preset conversion power. The magnitude of the first preset conversion power can be determined by the duty cycle of the pulse width modulation signal, so that the working state of the DC / DC converter circuit 400 can be quickly switched when the power consumption status of the input power supply and AC equipment changes, thus meeting the power supply requirements of the power supply circuit to switch quickly when the power consumption status changes.

[0047] In one embodiment, the power supply circuit also includes a bus capacitor connected to the DC bus 101. By setting the bus capacitor between the positive DC bus and the negative DC bus, rapid changes in voltage on the DC bus 101 can be avoided.

[0048] In one embodiment, see Figure 2 As shown, the power supply circuit in this embodiment also includes a second control circuit 120 connected to the AC / DC conversion circuit 300.

[0049] The second control circuit 120 is used to send a first indication signal to the first control circuit 110 when the AC / DC conversion circuit 300 is in the discharge state after converting the DC power on the DC bus 101 into AC power and sending it to the AC equipment through the output interface circuit 220; the first control circuit 110 is also used to send a first control command to the DC / DC conversion circuit 400 when it detects that the bus voltage of the DC bus 101 drops from a first voltage value to a second voltage value after receiving the first indication signal.

[0050] In this embodiment, the photovoltaic array is connected to the DC bus 101 through the DC input circuit 210. When the AC / DC conversion circuit 300 is in the discharge state, it converts the DC power on the DC bus 101 into AC power and outputs it to the output interface circuit 220. Then, the output interface circuit 220 outputs the AC power to the AC device. At this time, the second control circuit 120 sends a first indication signal to the first control circuit 110. The first control circuit 110 detects the bus voltage of the DC bus 101 based on the first indication signal, and sends a first control command to the DC / DC conversion circuit 400 when the bus voltage drops from the first voltage value to the second voltage value. In one embodiment, when the AC / DC converter circuit 300 is in a discharging state and converts the DC power on the DC bus 101 into AC power for output to the AC device, the second control circuit 120 sends a first indication signal to the first control circuit 110. The first indication signal is used to indicate that the AC / DC converter circuit 300 is in a discharging state. If the bus voltage on the DC bus 101 drops from the first voltage value to the second voltage value, it is determined that the power input from the DC input circuit 210 to the DC bus 101 is less than the required power of the AC device. At this time, the first control circuit 110 sends a first control command to the DC / DC converter circuit 400, and the operating state of the DC / DC converter circuit 400 switches from the current operating state to the discharging state. The DC / DC converter circuit 400 converts the DC power output from the battery module 500 into voltage according to the first preset conversion power and outputs it to the DC bus 101.

[0051] In one embodiment, the first indication signal is transmitted through the signal interface between the first control circuit 110 and the second control circuit 120. The first indication signal can be high level. When the signal interface between the first control circuit 110 and the second control circuit 120 undergoes a level flip, its level changes from low level to high level. At this time, the first control circuit 110 knows that the AC / DC conversion circuit 300 is in a discharging state based on the high level of the signal interface. If the bus voltage on the DC bus 101 drops from the first voltage value to the second voltage value, it is determined that the power input from the DC input circuit 210 to the DC bus 101 is less than the required power of the AC equipment. If the level of the signal interface between the first control circuit 110 and the second control circuit 120 is low level, it indicates that the AC / DC conversion circuit 300 is in a non-discharging state (e.g., standby state). At this time, even if the first control circuit 110 detects that the bus voltage on the DC bus 101 drops from the first voltage value to the second voltage value, the first control circuit 110 does not need to send the first control command to the DC / DC conversion circuit 400.

[0052] In one embodiment, if the AC device connected to the output interface circuit 220 does not require power, the AC / DC conversion circuit 300 is in standby mode, and the DC input circuit 210 stops inputting DC power to the DC bus 101. At this time, the signal interface level between the first control circuit 110 and the second control circuit 120 is low, indicating that the AC / DC conversion circuit 300 is in a non-discharge state (e.g., standby mode). If the first control circuit 110 detects that the bus voltage of the DC bus 101 drops from the first voltage value to the second voltage value, it does not need to send the first control command to the DC / DC conversion circuit 400. The DC / DC conversion circuit 400 maintains its current working state, and the working state of the DC / DC conversion circuit 400 does not need to be switched. At this time, the battery module 500 does not need to discharge externally.

[0053] In one embodiment, the voltage range of the first voltage value can be 400V-410V.

[0054] In one embodiment, the voltage range of the second voltage value can be 350V-390V.

[0055] In one embodiment, see Figure 3 As shown, the power supply circuit also includes a main control circuit 600.

[0056] Specifically, the main control circuit 600 generates a second control command based on the power demand of the AC equipment and the input power of the DC input circuit 210, and sends the second control command to the DC / DC converter circuit 400. The second control command controls the conversion power of the DC / DC converter circuit 400 so that the sum of the conversion power of the DC / DC converter circuit 400 and the input power of the DC input circuit 210 meets the power demand of the AC equipment.

[0057] In this embodiment, the AC device is connected to the output terminal of the output interface circuit 220, and the input terminal of the DC input circuit 210 is connected to the photovoltaic array. The main control circuit 600 generates a second control command to the DC / DC conversion circuit 400 based on the power demand of the AC device and the input power of the DC input circuit 210. That is, the conversion power of the DC / DC conversion circuit 400 is determined by the power demand of the AC device and the input power of the DC input circuit 210, so that the sum of the conversion power of the DC / DC conversion circuit 400 and the input power of the DC input circuit 210 meets the power demand of the AC device, which can avoid energy loss caused by the DC / DC conversion circuit 400 converting according to a fixed power.

[0058] In one embodiment, the second control command can be at least one pulse width modulation signal, and at least one pulse width modulation signal is connected one-to-one with the control terminal of the switching transistor in the DC / DC converter circuit 400, thereby adjusting the conversion power of the DC / DC converter circuit 400 by controlling the switching state of the switching transistor.

[0059] In one embodiment, see Figure 4 As shown, the power supply circuit also includes an AC input circuit 230 and a switching circuit 231.

[0060] Specifically, the input terminal of the AC input circuit 230 is used to connect to the AC power supply, the output terminal of the AC input circuit 230 is connected to the first terminal of the switch circuit 231, and the second terminal of the switch circuit 231 is connected to the AC / DC conversion circuit 300 and the output interface circuit 220 respectively.

[0061] In this embodiment, the main control circuit 600 is also used to generate a first switch control signal when it detects that the input power of the DC input circuit 210 is less than the required power of the AC device, and send the first switch control signal to the switch circuit 231. The first switch control signal is used to control the switch circuit 231 to close so as to output the AC power provided by the AC power supply to the AC device.

[0062] In this embodiment, the AC power supply is connected to the output interface circuit 220 via the AC input circuit 230 and the switch circuit 231. When the output power of the photovoltaic array decreases, the input power of the DC input circuit 210 is less than the power required by the AC device. The main control circuit 600 outputs a first switch control signal to the switch circuit 231 to control the switch circuit 231 to close, so that the AC power supply is connected to the output interface circuit 220. The AC power provided by the AC power supply is output to the AC device. At this time, the photovoltaic array and the AC power supply are given priority to power the AC device, avoiding the charging and discharging losses of the battery module 500 when it is powered on by the external power grid, and extending the working time of the battery module 500.

[0063] In one embodiment, the main control circuit 600 is further configured to generate a second switch control signal and a second control command when it detects that the input power of the DC input circuit 210 is greater than the required power of the AC device, send the second switch control signal to the switch circuit 231, and send the second control command to the DC / DC converter circuit 400. The second switch control signal is used to control the switch circuit 231 to disconnect; the second control command is used to control the DC / DC converter circuit 400 to switch from the current working state to the charging state, so as to convert the DC power on the DC bus 101 into voltage and charge the battery module 500.

[0064] In this embodiment, when the input power of the DC input circuit 210 is greater than the required power of the AC equipment, the main control circuit 600 sends a second switch control signal to the switch circuit 231 to control the switch circuit 231 to disconnect. At this time, the AC power supply stops supplying power to the output interface circuit 220. At the same time, the main control circuit 600 sends a second control command to the DC / DC conversion circuit 400 to control the DC / DC conversion circuit 400 to switch from the current working state to the charging state, so as to convert the DC power on the DC bus 101 into voltage and charge the battery module 500, so that when the output power of the photovoltaic array is large, the photovoltaic power can be fully utilized to supply power to the AC equipment and the battery module 500.

[0065] In one embodiment, the first control circuit 110 is further configured to send a first switch control signal to the switch circuit 231 and send a third control command to the DC / DC converter circuit 400 when the bus voltage of the DC bus 101 is detected to drop to a third voltage value. The third control command is used to control the DC / DC converter circuit 400 to enter a standby state. The third voltage value is greater than the first voltage value.

[0066] In this embodiment, when the bus voltage of the DC bus 101 is at the third voltage value, which is greater than the first voltage value, the output power of the photovoltaic array is weakened. At this time, the input power of the DC input circuit 210 is less than the required power of the AC equipment. The main control circuit 600 outputs a first switch control signal to the switch circuit 231 to close the switch circuit 231, so that the AC power supply is connected to the output interface circuit 220, and the AC power provided by the AC power supply is output to the AC equipment. At the same time, the main control circuit 600 sends a third control command to the DC / DC conversion circuit 400 to control the DC / DC conversion circuit 400 to enter the standby state. At this time, the photovoltaic array and the AC power supply are given priority to supply power to the AC equipment, avoiding the charging and discharging loss of the battery module 500 when it is powered on by the external power grid, and extending the service life of the battery module 500.

[0067] In one embodiment, the voltage range of the third voltage value can be 410-450V.

[0068] In one embodiment, the main control circuit 600 is further configured to send a third control command to the DC / DC conversion circuit 400 when it detects that the input power of the DC input circuit 210 is equal to the power required by the AC device.

[0069] In this embodiment, if the input power of the DC input circuit 210 is equal to the power required by the AC device, the main control circuit 600 sends a third control command to the DC / DC conversion circuit 400 to control the DC / DC conversion circuit 400 to enter the standby state. At the same time, no AC power supply is required, and the switch circuit 231 is disconnected.

[0070] In one embodiment, the power supply circuit priority is MPPT circuit > AC power supply > battery module 500. When the DC input circuit 210 has power output, that is, when the MPPT circuit has power output, the power of the MPPT circuit is used first to power the connected AC load. That is, after the AC / DC conversion circuit 300 converts the DC power on the DC bus 101 into AC power, it sends it to the AC device through the output interface circuit 220. The power output by the MPPT directly powers the AC device connected to the output interface circuit 220 through the AC / DC conversion circuit 300.

[0071] In one embodiment, when the MPPT circuit cannot meet the power requirements of the AC device, it will control the externally connected mains power (AC power supply) to power the AC device. When the MPPT circuit or the mains power fails, or when the mains power or the MPPT circuit cannot meet the power requirements of the connected AC device, the DC / DC converter circuit 400 will be activated and switched to the discharge state. The DC power output from the battery module 500 will be converted into voltage and output to the DC bus 101. Then, the AC / DC converter circuit 300 will convert the DC power on the DC bus 101 into AC power and send it to the AC device through the output interface circuit 220.

[0072] In one embodiment, the first control circuit 110 and the second control circuit 120 may be control circuits consisting only of switching transistors. For example, when a power failure is detected, a preset discharge program is first entered. This discharge program is pre-set and is used to control the AC / DC converter circuit 300 or the DC / DC converter circuit 400 to output the rated power.

[0073] In one embodiment, the second control command is a pulse width modulation signal.

[0074] In this embodiment, the main control circuit 600 is also used to adjust the duty cycle and frequency of the second control command according to the conversion power of the DC / DC converter circuit 400, the input power of the DC input circuit 210 and the power demand of the AC equipment, so that the sum of the conversion power of the DC / DC converter circuit 400 and the input power of the DC input circuit 210 meets the power demand of the AC equipment.

[0075] In this embodiment, the main control circuit 600 adjusts the output power of the AC / DC conversion circuit 300 by setting the duty cycle and frequency of the second control command, so that the sum of the conversion power of the DC / DC conversion circuit 400 and the input power of the DC input circuit 210 meets the power requirements of the AC equipment, thus avoiding the problem of abnormal operation or device damage of the AC equipment connected to the output interface circuit 220 due to excessively high or low output power of the AC / DC conversion circuit 300.

[0076] refer to Figure 6 As shown, this application embodiment also provides a power conversion device 700, including a housing 710, an output interface 720, and a power supply circuit as described in any of the above embodiments; the power supply circuit is disposed inside the housing 710; the output interface 720 is used to connect a load; the output interface 720 is connected to the output terminal of the power supply circuit.

[0077] In this embodiment, the housing 710 generally refers to the outer shell of the power conversion device 700, which plays a protective role for the circuit inside the power conversion device 700. By applying the above-mentioned power supply circuit to the power conversion device 700, the application scenarios of the power conversion device 700 can be greatly improved.

[0078] This application also provides an energy storage device, see [link to relevant documentation]. Figure 7 As shown, the energy storage device includes a battery module 500 and a power supply circuit as described above.

[0079] In this embodiment, the battery module 500 is connected to the output interface circuit 220 through the AC / DC conversion circuit 300 and the DC / DC conversion circuit 400. At this time, both the battery module 500 and the DC input circuit 210 serve as power supply branches for the output interface circuit 220. The first control circuit 110 and the second control circuit 120 determine the operating state of the AC / DC conversion circuit 300 and the DC / DC conversion circuit 400 based on the input power of the DC input circuit 210 and the power requirements of the AC equipment connected to the output interface circuit 220, and determine the control of charging, discharging and standby of the battery module 500.

[0080] In one embodiment, the energy storage device may further include a grid connection interface circuit, through which the energy storage device can be connected to other energy storage devices.

[0081] In one embodiment, see Figure 8 As shown, the battery module 500 includes a first switch S1, a second switch S2, a first diode D1, a second diode D2, and a battery module BAT.

[0082] Specifically, the DC / DC converter circuit 400 is connected to the power management system (BMS) in the battery module 500 through the first positive terminal P+ and the first negative terminal P-. The first switch S1, the second switch S2, the first diode D1, and the second diode D2 constitute the power management system. The first terminal of the first switch S1 and the anode of the first diode D1 are connected to the positive terminal B+ of the battery module BAT. The second terminal of the first switch S1, the cathode of the first diode D1, the cathode of the second diode D2, and the first terminal of the second switch S2 are connected together. The anode of the second diode D2 and the second terminal of the second switch S2 are connected to the first positive terminal P+. The negative terminal B- of the battery module BAT is connected to the first negative terminal P-.

[0083] In this embodiment, the main control circuit 600 can control the charging, discharging, and standby switching of the battery module BAT by controlling the switching states of the first switch S1 and the second switch S2. For example, when charging the battery module BAT, the first switch S1 can be closed and the second switch S2 can be opened first, thus pre-charging the battery module BAT. Then, when the voltage at the first positive terminal P+ is detected to be greater than the voltage at the positive terminal B+, both the first switch S1 and the second switch S2 are closed to charge the battery module BAT. When discharging the battery module BAT, the first switch S1 can be opened and the second switch S2 can be closed first, thus pre-discharging the battery module BAT. When the voltage at the first positive terminal P+ is detected to be less than the voltage at the positive terminal B+, both the first switch S1 and the second switch S2 are closed to discharge the battery module BAT. When both the first switch S1 and the second switch S2 are opened, the battery module BAT is in standby mode.

[0084] In one embodiment, the first switch S1 and the second switch S2 can be switching devices such as relays or MOSFETs.

[0085] This application also provides a power supply system, which includes a photovoltaic array, an energy storage device, and a power supply circuit as described above.

[0086] Specifically, the photovoltaic array is connected to the DC input circuit 210 in the power supply circuit. The photovoltaic array is used to output voltage to the DC input circuit 210 after photoelectric conversion. The energy storage device is connected to the output terminal of the power supply circuit as a load.

[0087] By applying the power supply circuit of this embodiment to the power supply system, the stability of the power supply system can be improved. For example, the main control circuit in the power supply circuit can precisely control the switching circuit and the power conversion circuit, which greatly avoids the repeated switching of the switching circuit and the power conversion circuit when the photovoltaic array is under weak light conditions, thus avoiding the loss of the switching circuit and the power conversion circuit, and also avoids the problem of damage to the downstream circuits connected to it due to the frequent start-up of the power conversion circuit.

[0088] The beneficial effects of this application embodiment are as follows: By sequentially connecting the output interface circuit, AC / DC conversion circuit, DC bus, and DC / DC conversion circuit, the DC input circuit converts the DC power input from the photovoltaic array into power and outputs the rated voltage to the DC bus. The AC / DC conversion circuit converts the DC power on the DC bus into AC power and sends it to the AC equipment through the output interface circuit. When the first control circuit detects that the bus voltage of the DC bus drops from the first voltage value to the second voltage value, it sends a first control command to the DC / DC conversion circuit, switching the DC / DC conversion circuit from the current working state to the discharge state. The DC power output from the battery module is converted into voltage according to the first preset conversion power and then output to the DC bus. Thus, the working state of the DC / DC conversion circuit can be quickly switched when the power input and the power consumption state of the AC equipment change, satisfying the rapid switching of the power supply circuit.

[0089] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0090] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A power supply circuit, characterized in that: The power supply circuit includes an AC / DC conversion circuit, a DC / DC conversion circuit, a first control circuit, a second control circuit, an output interface circuit and a DC input circuit; The input end of the output interface circuit is connected to the first end of the AC / DC conversion circuit, and the output end of the output interface circuit is used to connect to an AC device; the second end of the AC / DC conversion circuit is connected to the first end of the DC / DC conversion circuit through a DC bus, and the second end of the DC / DC conversion circuit is used to connect to a battery module; the input end of the DC input circuit is connected to a photovoltaic array, and the output end of the DC input circuit is connected to the DC bus, the first control circuit is connected to the DC bus and the DC / DC conversion circuit respectively, and the second control circuit is connected to the AC / DC conversion circuit; The DC input circuit is used to convert the DC power input by the photovoltaic array into power and then output a rated voltage to the DC bus; The AC / DC conversion circuit is used to convert the DC power on the DC bus into AC power and send it to the AC device through the output interface circuit; The DC / DC conversion circuit is used to convert the voltage of the DC power on the DC bus to charge the battery module; and is also used to convert the voltage of the DC power output by the battery module to output it to the DC bus; The second control circuit is used to send a first indication signal to the first control circuit when the AC / DC conversion circuit is in a discharge state of converting the DC power on the DC bus into AC power and sending it to the AC device through the output interface circuit; The first indication signal is transmitted via a signal interface between the first control circuit and the second control circuit; The first control circuit is used to send a first control instruction to the DC / DC conversion circuit when receiving the first indication signal and detecting that the bus voltage of the DC bus drops from a first voltage value to a second voltage value. The first control instruction is used to control the DC / DC conversion circuit to switch from a current working state to a discharging state, and convert the DC power output by the battery module into a voltage according to a first preset conversion power and output it to the DC bus; the first control instruction includes at least one pulse width modulation signal, and at least one of the pulse width modulation signals is connected to a control end of a switch tube in the DC / DC conversion circuit in a one-to-one correspondence.

2. The power supply circuit according to claim 1, characterized in that: The power supply circuit also includes a main control circuit; The main control circuit is used to generate a second control instruction according to the required power of the AC device and the input power of the DC input circuit, and send the second control instruction to the DC / DC conversion circuit, and the second control instruction controls the conversion power of the DC / DC conversion circuit so that the sum of the conversion power of the DC / DC conversion circuit and the input power of the DC input circuit meets the required power of the AC device.

3. The power supply circuit according to claim 2, characterized in that: The power supply circuit further includes an AC input circuit and a switch circuit; the input end of the AC input circuit is used to connect to an AC power source, the output end of the AC input circuit is connected to a first end of the switch circuit, and the second end of the switch circuit is connected to the AC / DC conversion circuit and the output interface circuit respectively; The main control circuit is also used to generate a first switch control signal when it detects that the input power of the DC input circuit is less than the required power of the AC device, and send the first switch control signal to the switch circuit. The first switch control signal is used to control the switching circuit to close so as to output the AC power provided by the AC power supply to the AC device.

4. The power supply circuit according to claim 3, characterized in that: The main control circuit is also used to generate a second switch control signal and a second control instruction when it detects that the input power of the DC input circuit is greater than the required power of the AC device, send the second switch control signal to the switch circuit, and send the second control instruction to the DC / DC conversion circuit, the second switch control signal is used to control the switch circuit to disconnect; the second control instruction is used to control the DC / DC conversion circuit to switch from the current working state to the charging state, so as to charge the battery module after the DC power on the DC bus is converted into voltage.

5. The power supply circuit according to claim 4, characterized in that: The first control circuit is also used to send the first switch control signal to the switch circuit and send a third control instruction to the DC / DC conversion circuit when it is detected that the bus voltage of the DC bus is reduced to a third voltage value, and the third control instruction is used to control the DC / DC conversion circuit to enter a standby state; wherein the third voltage value is greater than the first voltage value.

6. The power supply circuit according to claim 5, characterized in that: The main control circuit is also used to send the third control instruction to the DC / DC conversion circuit when it is detected that the input power of the DC input circuit is equal to the required power of the AC device.

7. The power supply circuit according to claim 2, characterized in that: The second control instruction is a pulse width modulation signal; The main control circuit is also used to adjust the duty cycle and frequency of the second control instruction according to the conversion power of the DC / DC conversion circuit, the input power of the DC input circuit and the required power of the AC device, so that the sum of the conversion power of the DC / DC conversion circuit and the input power of the DC input circuit meets the required power of the AC device.

8. A power conversion device, characterized in that: The power conversion device comprises the power supply circuit according to any one of claims 1 to 7.

9. An energy storage device, characterized in that: The energy storage device comprises a battery module and a power supply circuit as described in any one of claims 1 to 7.

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