Power supply circuit and power consuming device

Abstract

The application belongs to the technical field of power generation, and particularly relates to a power supply circuit and a power utilization device. The application aims to solve the problem of poor safety of the existing power supply circuit. The power supply circuit comprises a first switch module, a voltage detection module and a second switch module. The first switch module is connected with an output end of a power generation assembly. The second switch module is connected with an input end of a target power grid. The voltage detection module is connected with a control module of the power generation device. When the power generation assembly does not generate power, a first connection between the power generation assembly and the first switch module is disconnected. A second connection between the target power grid and the second switch module is disconnected. When the power generation assembly generates power, and a voltage value on both sides of the target power grid detected by the voltage detection module is less than a grid-connected voltage threshold, the control module controls the first switch module to disconnect the first connection and controls the second switch module to turn on the second connection. Through the above setting, the safety of the power supply circuit is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power generation, and particularly relates to a power supply circuit and a power consumption device. BACKGROUND

[0002] Green renewable energy power generation methods such as solar photovoltaic power generation (referred to as photovoltaic power generation) and wind power generation are increasingly valued. Taking photovoltaic power generation as an example, when using an existing photovoltaic power generation power supply circuit, there is a loss of electric energy (for example, a loss of electric energy in a direct current inversion process on the power generation side and a loss of electric energy in an alternating current rectification process on the power consumption side). In order to reduce the electric energy loss of the power supply circuit, some existing implementations propose a power supply circuit in which direct current output by a photovoltaic cell assembly is directly connected in parallel to a power consumption device on a direct current power grid.

[0003] However, the existing power supply circuit has a high safety hazard. SUMMARY

[0004] In order to solve the above problems in the prior art, that is, to solve the problem that the existing power supply circuit has a high safety hazard, in a first aspect, the application provides a power supply circuit, a power generation device comprising: a power generation assembly, and a control module, the power supply circuit comprising: a first switch module, a voltage detection module, and a second switch module; a first end of the first switch module is connected with an output end of the power generation assembly; a second end of the first switch module and a first end of the second switch module are both connected with a first end of the voltage detection module; a third end of the first switch module and a second end of the second switch module are both connected with a second end of the voltage detection module; a third end of the second switch module is connected with an input end of a target power grid; a third end of the voltage detection module is connected with a first end of the control module; a second end of the control module is connected with a fourth end of the first switch module and a fourth end of the second switch module.

[0005] When the power generation assembly is not generating power, the first switch module is used to disconnect a first connection between the power generation assembly and the first switch module; and the second switch module is used to disconnect a second connection between the target power grid and the second switch module.

[0006] When the power generation assembly is generating power, the voltage detection module is used to detect voltage values on both sides of the target power grid and output the voltage values to the control module; and the control module is used to control the first switch module to disconnect the first connection and control the second switch module to turn on the second connection when the voltage values are less than a grid-connected voltage threshold.

[0007] In the preferred technical scheme of the power supply circuit, the first switch module comprises a first switch and a second switch, a first end of the first switch is connected with a positive output end of the power generation assembly, and a second end of the first switch is connected with a first end of the voltage detection module; a first end of the second switch is connected with a negative output end of the power generation assembly, and a second end of the second switch is connected with a second end of the voltage detection module; the first switch module disconnects the first connection, comprising that the first switch and the second switch are both disconnected;

[0008] and / or,

[0009] The second switch module comprises a third switch and a fourth switch, a first end of the third switch is connected with a positive input end of the target power grid, and a second end of the third switch is connected with the first end of the voltage detection module; a first end of the fourth switch is connected with a negative input end of the target power grid, and a second end of the fourth switch is connected with the second end of the voltage detection module; the second switch module disconnects the second connection, comprising that the third switch and the fourth switch are both disconnected; the second switch module turns on the second connection, comprising that the third switch and the fourth switch are both closed.

[0010] In the preferred technical scheme of the power supply circuit, the voltage detection module comprises a voltage sampling unit and an isolation unit.

[0011] The second end of the first switch module and the first end of the second switch module are both connected with a first end of the voltage sampling unit, and the third end of the first switch module and the second end of the second switch module are both connected with a second end of the voltage sampling unit; a third end of the voltage sampling unit is connected with a first end of the isolation unit; a second end of the isolation unit is connected with a first end of the control module.

[0012] The voltage sampling unit is used for sampling voltages on both sides of the target power grid to obtain initial voltages on both sides of the target power grid.

[0013] The isolation unit is used for isolating the target power grid from the control module when the initial voltage is zero, and determining voltage values on both sides of the target power grid according to the initial voltage.

[0014] In the preferred technical scheme of the power supply circuit, the voltage sampling unit comprises a first resistor, a second resistor and a first amplification subunit.

[0015] The second end of the first switch module and the first end of the second switch module are connected with the first end of the first resistor; the second end of the first resistor and the first end of the second resistor are connected with the first end of the first amplification subunit; the second end of the first amplification subunit is connected with the first end of the isolation unit; the third end of the first switch module and the second end of the second switch module are connected with the second end of the second resistor.

[0016] The first amplification subunit is configured to amplify the voltage sampled from both sides of the target power grid to obtain the initial voltage.

[0017] In the preferred technical solution of the power supply circuit, the isolation unit comprises a first optocoupler diode, a second optocoupler diode, and a third optocoupler diode.

[0018] The second end of the first amplification subunit is connected with the negative electrode of the first optocoupler diode, and the positive electrode of the first optocoupler diode is connected with the first output end of the target power grid; the first end of the first amplification subunit is connected with the negative electrode of the second optocoupler diode; the positive electrode of the second optocoupler diode and the positive electrode of the third optocoupler diode are grounded; and the negative electrode of the third optocoupler diode is connected with the first end of the control module.

[0019] In the preferred technical solution of the power supply circuit, the voltage detection module further comprises a second amplification unit, and the negative electrode of the third optocoupler diode is connected with the first end of the control module through the second amplification unit.

[0020] The second amplification unit is configured to amplify the voltage across the third optocoupler diode to obtain an amplified voltage as the voltage value of both sides of the target power grid.

[0021] In the preferred technical solution of the power supply circuit, the third end of the first amplification subunit is connected with the first output end of the target power grid; and the target power grid is configured to provide the working voltage of the first amplification subunit for the first amplification subunit.

[0022] The second amplification unit is further connected with the third end of the control module; and the control module is configured to provide the working voltage of the second amplification unit for the second amplification unit.

[0023] In the preferred technical solution of the power supply circuit, when the power generation assembly generates power, the control module is further configured to control the first switch module to turn on the first connection and control the second switch module to turn on the second connection when the voltage value is greater than or equal to the grid-connected voltage threshold.

[0024] In the preferred technical solution of the power supply circuit, the power generation assembly is a photovoltaic power generation assembly; the photovoltaic power generation assembly outputs direct current, and the target power grid is a direct current power grid.

[0025] In a second aspect, the present application provides a power utilization device, which comprises the power supply circuit according to any one of the preceding first aspect.

[0026] As can be understood by those skilled in the art, in the power supply circuit and the power utilization device provided by the present application, when the power generation assembly does not generate power, the first connection between the power generation assembly and the first switch module is disconnected, and the second connection between the target power grid and the second switch module is disconnected. Through the power supply circuit, when the power generation assembly does not generate power, the target power grid will be physically isolated from the power generation assembly regardless of whether the target power grid has power, thus avoiding the situation that there is still current in the circuit between the target power grid and the power generation assembly, and further improving the safety of the power supply circuit. When the power generation assembly generates power, the voltage values on both sides of the target power grid can be detected by the voltage detection module. The first switch module can be controlled to disconnect the first connection, and the second switch module can be controlled to conduct the second connection when the voltage value is less than the grid-connected voltage threshold value by the control module. Through the power supply circuit, the power generation assembly can be isolated from the target power grid when the target power grid has no power or the voltage does not meet the grid-connected condition, thus avoiding the problem that the power generation assembly is still connected to the target power grid when the target power grid loses power, further avoiding the risk of electric shock of the user, and improving the safety of the power supply circuit. By controlling the second switch module to conduct the second connection, the control module can continue to determine whether the voltage values on both sides of the target power grid are less than the grid-connected voltage threshold value, continuously monitoring the voltage on both sides of the target power grid, and further improving the safety of the power supply circuit. BRIEF DESCRIPTION OF DRAWINGS

[0027] The preferred embodiments of the power supply circuit of the present application will be described below with reference to the accompanying drawings and in conjunction with a power supply circuit. The drawings are as follows:

[0028] Figure 1 FIG. 1 is a structural schematic diagram of a photovoltaic power generation power supply circuit;

[0029] Figure 2 FIG. 2 is a structural schematic diagram of a power supply circuit provided by the present application;

[0030] Figure 3 FIG. 3 is a structural schematic diagram of another power supply circuit provided by the present application;

[0031] Figure 4 FIG. 4 is a structural schematic diagram of a voltage detection module provided by the present application;

[0032] Figure 5 FIG. 5 is a structural schematic diagram of a voltage sampling unit provided by the present application;

[0033] Figure 6 A schematic diagram of the structure of an isolation unit provided in this application;

[0034] Figure 7 This is a schematic diagram of another power supply circuit provided in this application. Detailed Implementation

[0035] First, those skilled in the art should understand that these embodiments are merely for explaining the technical principles of this application and are not intended to limit the scope of protection of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0036] Secondly, it should be noted that in the description of this application, the terms "inner" and "outer," etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is merely for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0037] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] Solar photovoltaic (PV) power generation and wind power, among other green and renewable energy sources, are receiving increasing attention. Taking PV power generation as an example... Figure 1 This is a schematic diagram of an existing photovoltaic power generation circuit. Figure 1 As shown, in existing photovoltaic power generation circuits, an inverter and an AC rectifier are connected between the photovoltaic modules and the electrical equipment. The inverter converts the direct current (DC) output from the photovoltaic modules into AC power, which is then output to the AC rectifier on the power consumption side, enabling long-distance power transmission. The AC rectifier converts the AC power output from the inverter into DC power usable by the electrical equipment.

[0039] When using existing photovoltaic power generation circuits, there are two energy loss processes: one is the DC inversion process on the generation side, and the other is the AC rectification process on the consumption side. In other words, existing photovoltaic power generation circuits have a significant energy loss problem.

[0040] To reduce power loss in power supply circuits, some existing implementations have proposed methods that directly connect the DC power output from photovoltaic modules to the power-consuming equipment on the DC grid.

[0041] However, when using the existing power supply circuit, if the DC grid loses power (e.g., during power outage maintenance), the photovoltaic modules will still be connected to the DC grid, potentially causing electric shock to users (e.g., circuit maintenance personnel). Even when the photovoltaic modules are not generating electricity, if the DC grid has other power sources, current will still flow between the DC grid and the photovoltaic module, posing a safety hazard.

[0042] In view of the above-mentioned problems of existing power supply circuits, this application proposes a power supply circuit in which there is no power transmission when the power consumption side loses power or the power generation side does not generate power, so as to improve the safety of the power supply circuit.

[0043] The technical solution of this application will be described in detail below with reference to specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0044] Figure 2 This is a schematic diagram of a power supply circuit provided in this application. Figure 2 As shown, the power generation device may include: a power generation component and a control module. The power supply circuit may include: a first switching module, a voltage detection module, and a second switching module. The first terminal of the first switching module may be connected to the output terminal of the power generation component. The second terminal of the first switching module and the first terminal of the second switching module may both be connected to the first terminal of the voltage detection module. The third terminal of the first switching module and the second terminal of the second switching module are both connected to the second terminal of the voltage detection module. The third terminal of the second switching module may be connected to the input terminal of the target power grid. The third terminal of the voltage detection module may be connected to the first terminal of the control module. The second terminal of the control module may be connected to the fourth terminals of both the first and second switching modules.

[0045] It should be understood that this application does not limit the type of the aforementioned power generation component. For example, the power generation component may be any existing power generation component such as a photovoltaic power generation component or a wind power generation component.

[0046] Optionally, taking a photovoltaic (PV) power generation module as an example, the output of the PV module can be direct current (DC). Correspondingly, the target power grid can be a DC power grid. When the target power grid is a DC power grid, the electrical devices in the DC power grid can be DC electrical devices. For example, the DC electrical device can be any type of electrical device such as a water heater or air conditioner; this application does not limit this. In this implementation, the power generation module can be directly connected in parallel to both sides of the DC power grid without the need for inversion or rectification, reducing power loss.

[0047] Alternatively, in some embodiments, the target power grid can also be an AC power grid. In this implementation, taking the output of DC power from the power generation component as an example, the power supply circuit may further include an inverter circuit for converting DC power into AC power, so that electrical devices in the target power grid that use AC power can use the AC power obtained by the inverter.

[0048] For example, such as Figure 2 As shown, the connection between the first terminal of the first switching module and the output terminal of the power generation component may include, for example, the positive terminal of the first terminal of the first switching module being connected to the positive terminal of the output terminal of the power generation component, and the negative terminal of the first terminal of the first switching module being connected to the negative terminal of the output terminal of the power generation component.

[0049] For example, such as Figure 2 As shown, the connection between the third terminal of the second switching module and the input terminal of the target power grid may include, for example, connecting the positive terminal of the third terminal of the second switching module to the positive terminal of the input terminal of the target power grid, and connecting the negative terminal of the third terminal of the second switching module to the negative terminal of the input terminal of the target power grid.

[0050] In some embodiments, the power generation component can also be connected to the control module. The power generation component can provide operating voltage to the control module.

[0051] When the power generation component is not generating electricity, the first switch module can be used to disconnect the first connection between the power generation component and the first switch module. The second switch module can be used to disconnect the second connection between the target power grid and the second switch module.

[0052] For example, taking the aforementioned power generation component as the source of operating voltage for the control module, when the power generation component is not generating electricity, the control module is powered off. After the control module is powered off, the first switch module and the second switch module can return to their initial states. This initial state can be characterized by the first connection being disconnected and the second connection being disconnected. Through this method, regardless of whether the target power grid has power, as long as the power generation component is not generating electricity, the target power grid will be physically disconnected from the power generation component and the control module.

[0053] The voltage detection module can be configured to detect the voltage values on both sides of the target power grid and output the voltage values to the control module. The control module can be configured to control the first switch module to disconnect the first connection and control the second switch module to connect the second connection when the voltage values are less than a grid-connected voltage threshold.

[0054] It should be understood that the number of the power consumption devices included in the target power grid and the types of the power consumption devices (e.g., air conditioners, water heaters, etc.) are not limited in the present application.

[0055] Optionally, when the voltage values are less than the grid-connected voltage threshold, it indicates that the target power grid has no power or the voltage fails to meet the grid-connected condition. Therefore, by controlling the first switch module to disconnect the first connection when the voltage values on both sides of the target power grid are less than the grid-connected voltage threshold, the power generation assembly is isolated from the target power grid, which avoids the problem that the power generation assembly is still connected to the target power grid when the target power grid loses power, and further avoids the risk of electric shock of the user, thereby improving the safety of the power supply circuit. By controlling the second switch module to connect the second connection, the control module can continue to determine whether the voltage values on both sides of the target power grid are less than the grid-connected voltage threshold, which continuously monitors the voltage on both sides of the target power grid, and further improves the safety of the power supply circuit.

[0056] For example, the grid-connected voltage threshold can be pre-stored in the control module.

[0057] In the present embodiment, when the power generation assembly is not generating power, the first connection between the power generation assembly and the first switch module is disconnected, and the second connection between the target power grid and the second switch module is disconnected. Through the power supply circuit, when the power generation assembly is not generating power, the target power grid is physically isolated from the power generation assembly regardless of whether the target power grid has power, which avoids the situation that the circuit between the target power grid and the power generation assembly still has current, and further improves the safety of the power supply circuit. When the power generation assembly is generating power, the voltage detection module can detect the voltage values on both sides of the target power grid. The control module can control the first switch module to disconnect the first connection and control the second switch module to connect the second connection when the voltage values are less than a grid-connected voltage threshold. Through the power supply circuit, when the target power grid has no power or the voltage fails to meet the grid-connected condition, the power generation assembly is isolated from the target power grid, which avoids the problem that the power generation assembly is still connected to the target power grid when the target power grid loses power, and further avoids the risk of electric shock of the user, thereby improving the safety of the power supply circuit. By controlling the second switch module to connect the second connection, the control module can continue to determine whether the voltage values on both sides of the target power grid are less than the grid-connected voltage threshold, which continuously monitors the voltage on both sides of the target power grid, and further improves the safety of the power supply circuit.

[0058] As a possible implementation, when the power generation assembly generates power, the control module can also be configured to control the first switch module to turn on the first connection and control the second switch module to turn on the second connection when the voltage value is greater than or equal to the grid-connected voltage threshold.

[0059] Optionally, if the voltage value is greater than or equal to the grid-connected voltage threshold, it indicates that the target grid voltage meets the grid-connected condition. By turning on the first connection and the second connection in the power supply circuit, the power supply to the target grid by the power generation assembly is realized.

[0060] The structure of the first switch module and the structure of the second switch module are described in detail as follows:

[0061] As a possible implementation, Figure 3 Another structure diagram of a power supply circuit is provided for the present application. As shown Figure 3 It should be understood that the control module is not shown in the above description Figure 3 The first switch module can include a first switch and a second switch. The first end of the first switch can be connected to the positive output end of the power generation assembly. The second end of the first switch can be connected to the first end of the voltage detection module. The first end of the second switch can be connected to the negative output end of the power generation assembly. The second end of the second switch can be connected to the second end of the voltage detection module.

[0062] In this implementation, the first switch module disconnecting the first connection can include both the first switch and the second switch being disconnected. That is, when the power generation assembly does not generate power, both the first switch and the second switch can be disconnected. When the power generation assembly generates power and the voltage value on both sides of the target grid is less than the grid-connected voltage threshold, the first switch and the second switch remain in the disconnected state. When the power generation assembly generates power and the voltage value is greater than or equal to the grid-connected voltage threshold, the first switch and the second switch can be closed to turn on the first connection.

[0063] The first switch and the second switch in the first switch module lay the foundation for disconnecting the first connection and turning on the first connection, thus laying the foundation for improving the safety of the power supply circuit.

[0064] As a possible implementation, as shown Figure 3 The second switch module can include a third switch and a fourth switch. The first end of the third switch can be connected to the positive input end of the target grid. The second end of the third switch can be connected to the first end of the voltage detection module. The first end of the fourth switch can be connected to the negative input end of the target grid. The second end of the fourth switch can be connected to the second end of the voltage detection module.

[0065] In the implementation, the second switch module being disconnected from the second connection can include: the third switch and the fourth switch being both disconnected. The second switch module being connected to the second connection can include: the third switch and the fourth switch being both connected.

[0066] That is, the third switch and the fourth switch can be both disconnected when the power generation assembly is not generating electricity. When the power generation assembly is generating electricity, and the voltage value on both sides of the target power grid is less than the grid-connected voltage threshold, the third switch and the fourth switch can be switched to the closed state. When the power generation assembly is generating electricity, and the voltage value is greater than or equal to the grid-connected voltage threshold, the first switch and the second switch can be kept in the closed state to connect the second connection.

[0067] The third switch and the fourth switch in the second switch module provide a basis for disconnecting the second connection and connecting the second connection, and thus provide a basis for improving the safety of the power supply circuit.

[0068] The structure of the voltage detection module will be described in detail below.

[0069] Figure 4 A structure diagram of a voltage detection module provided in the present application is shown in FIG. 3. As a possible implementation, the voltage detection module can include a voltage sampling unit and an isolation unit. Figure 4

[0070] The second end of the first switch module and the first end of the second switch module can be connected to the first end of the voltage sampling unit. The third end of the first switch module and the second end of the second switch module can be connected to the second end of the voltage sampling unit. The third end of the voltage sampling unit can be connected to the first end of the isolation unit. The second end of the isolation unit can be connected to the first end of the control module.

[0071] The voltage sampling unit can be used to sample the voltage on both sides of the target power grid to obtain the initial voltage on both sides of the target power grid.

[0072] Figure 5 A structure diagram of a voltage sampling unit provided in the present application is shown in FIG. 4. As a possible implementation, the voltage sampling unit can include a first resistor, a second resistor, and a first amplification subunit. Figure 5

[0073] The second end of the first switch module and the first end of the second switch module can be connected to the first end of the first resistor. The second end of the first resistor and the first end of the second resistor can be connected to the first end of the first amplification subunit. The second end of the first amplification subunit can be connected to the first end of the isolation unit. The third end of the first switch module and the second end of the second switch module can be connected to the second end of the second resistor.​​

[0074] The first and second resistors mentioned above can serve as sampling resistors for sampling voltage from both sides of the target power grid. The first amplification subunit mentioned above can be used to amplify the voltage obtained from the voltage sampling from both sides of the target power grid to obtain the initial voltage mentioned above.

[0075] For example, the first amplification subunit described above can be any existing operational amplifier, and this application does not limit it. This application also does not limit the resistance value of the first resistor, the resistance value of the second resistor, or the voltage amplification factor of the first amplification subunit.

[0076] Through the first and second resistors mentioned above, the power supply circuit can sample voltage from both sides of the target power grid. The sampled voltage can be amplified by the first amplification subunit to obtain the initial voltage, which is then input to the isolation unit. This allows the isolation unit to determine whether to isolate the target power grid from the control module based on the magnitude of the initial voltage, further improving the safety of the power supply circuit.

[0077] The aforementioned isolation unit can be used to isolate the target power grid from the control module when the initial voltage is zero, and to determine the voltage values ​​on both sides of the target power grid based on the initial voltage.

[0078] Figure 6 This is a schematic diagram of an isolation unit provided in this application. Figure 6 As shown, in some embodiments, the isolation unit may include: a first optocoupler diode, a second optocoupler diode, and a third optocoupler diode.

[0079] The second terminal of the aforementioned first amplification subunit can be connected to the negative terminal of the first optocoupler diode. The positive terminal of the first optocoupler diode can be connected to the first output terminal of the target power grid. The first terminal of the aforementioned first amplification subunit can be connected to the negative terminal of the second optocoupler diode. The positive terminals of the second and third optocouplers can both be grounded. The negative terminal of the third optocoupler diode can be connected to the first terminal of the control module.

[0080] In this embodiment, the anode of the first optocoupler diode is connected to the first output terminal of the target power grid, enabling the target power grid to provide a positive operating voltage to the first optocoupler diode. In some embodiments, the anode of the first optocoupler diode can also be connected to the first output terminal of the target power grid via a voltage conversion module. This voltage conversion module can convert the voltage at the first output terminal of the target power grid into the operating voltage required for the anode of the first optocoupler diode.

[0081] The first and second optocoupler diodes generate different brightness according to the voltage on both sides of the target power grid, and the third optocoupler diode generates different current according to the brightness, so that the voltage value input to the control module changes with the current. When the initial voltage is zero, the first and second optocoupler diodes are not bright, and the voltage across the third optocoupler diode is zero, so the voltage value input to the control module is zero, thereby achieving isolation between the target power grid and the control module (i.e., isolation between the target power grid and the control module when the target power grid is powered off), and further improving the safety of the power supply circuit.

[0082] It should be understood that the isolation unit can also achieve "isolating the target power grid from the control module when the initial voltage is zero, and determining the voltage value on both sides of the target power grid according to the initial voltage" through other existing circuits, which is not limited in the present application.

[0083] In some embodiments, the voltage detection module can further include a second amplification unit, the negative electrode of the third optocoupler diode is connected to the first end of the control module through the second amplification unit.

[0084] The second amplification unit amplifies the voltage across the third optocoupler diode to obtain an amplified voltage as the voltage value on both sides of the target power grid.

[0085] Through the second amplification unit, the voltage across the third optocoupler diode is amplified and output to the control module as the voltage value on both sides of the target power grid, so that the control module can determine whether the voltage value is less than the grid-connected voltage threshold based on the amplified voltage, improving the accuracy of the control module in making the determination, and further improving the accuracy of the control module in controlling the first and second switch modules based on the determination result, thereby further improving the safety of the power supply circuit.

[0086] Alternatively, in some embodiments, the negative electrode of the third optocoupler diode of the isolation unit can also be directly connected to the first end of the control module.

[0087] In some embodiments, the third end of the first amplification subunit can be connected to the first output end of the target power grid. The target power grid can be used to provide the working voltage of the first amplification subunit for the first amplification subunit. The second amplification unit can also be connected to the third end of the control module. The control module can be used to provide the working voltage of the second amplification unit for the second amplification unit.

[0088] Optionally, the third end of the first amplification subunit can be directly connected with the first output end of the target power grid, for example. Alternatively, the third end of the first amplification subunit can also be connected with the first output end of the target power grid through a voltage conversion module or the like. The voltage conversion module can convert the voltage value of the first output end of the target power grid into the working voltage of the first amplification subunit, so that the first amplification subunit can work.

[0089] Optionally, the second amplification unit can be directly connected with the third end of the control module. Alternatively, the second amplification unit can also be connected with the third end of the control module through a voltage conversion module or the like. The voltage conversion module can convert the voltage value of the third end of the control module into the working voltage of the second amplification unit, so that the second amplification unit can work.

[0090] In the embodiment, the voltage sampling unit in the voltage detection module can sample the voltage on both sides of the target power grid to obtain the initial voltage on both sides of the target power grid. The isolation unit can isolate the target power grid from the control module when the initial voltage is zero, further improving the safety of the power supply circuit. By determining the voltage value on both sides of the target power grid through the initial voltage, the voltage value can be output to the control module to realize the monitoring of the target power grid in the isolated state.

[0091] Taking the above target power grid as a direct current power grid, the above power generation assembly as a photovoltaic power generation assembly, and the above control module as a control system as an example, Figure 7 Another structure schematic diagram of a power supply circuit is provided in the present application. As shown in Figure 7 , wherein DC+ represents the positive output end of the power generation assembly; DC- represents the negative output end of the power generation assembly. DC_O+ represents the positive end of the direct current power grid; DC_O- represents the negative end of the direct current power grid. V DC O is the first end of the control module.

[0092] K1 represents the above first switch; K2 represents the above second switch; K3 represents the above third switch; K4 represents the above fourth switch. R4 represents the above first resistor, and R5 represents the above second resistor. U2 represents the above first amplification subunit. U1 represents the isolation unit, which can be a linear optocoupler, and U3 can be used to represent the second amplification unit.

[0093] As shown in Figure 7 , wherein C1 is an anti-oscillation capacitor, and R2 is a current-limiting resistor (which can be used to protect the optocoupler diode in U1). R3 is also a resistor, which can be used to adjust the amplification factor of U3.

[0094] In addition, the Vcc' end of the U2 is connected with the first output end of the target DC grid. The target DC grid can be used to provide the working voltage of the first amplification subunit for the first amplification subunit (or in other words, the DC grid can be used as the primary working power supply of the U3). The 5V interface of the U1 is connected with the anode of the first optocoupler diode, and can be connected with the first output end of the target DC grid. The Vcc end of the U3 can be connected with the third end of the control module. The control module can be used to provide the working voltage for the U3.

[0095] It should be understood that Figure 7 The control module is not shown, and the connection relationship between each device and the control module. For example, the connection relationship between different devices and the control module can refer to the structure described in any of the foregoing embodiments, and will not be described here.

[0096] Based on the power supply circuit as shown in Figure 7 When the photovoltaic cell assembly does not generate electricity, the control system (i.e. the aforementioned control module) is not powered, and K1-K4 are all initially disconnected, so that the photovoltaic cell assembly and the control system are physically disconnected from the external DC grid regardless of whether the external DC grid has power.

[0097] When the photovoltaic cell assembly starts to generate electricity, the control system starts to work, keeps K1 and K2 disconnected, and closes K3 and K4. The optocoupler primary of the linear optocoupler can work (the diode is bright) or not work (the diode is not bright) according to whether the external DC grid has power.

[0098] If the external DC grid (i.e. the DC grid) has no power or the voltage does not reach the grid-connection condition (i.e. the aforementioned voltage value is less than the grid-connection voltage threshold), K1 and K2 are disconnected, K3 and K4 are closed, and the control system always monitors the state of the external DC grid until the voltage values on both sides of the DC grid reach the grid-connection condition.

[0099] If the voltage of the external DC grid reaches the grid-connection condition, the control system can control K1, K2, K3 and K4 to be closed, and the DC power generated by the photovoltaic cell assembly is connected to the external DC grid through the control of the control system.

[0100] In the embodiment, the four-switch isolation circuit topology described above allows the photovoltaic cell assembly to be physically isolated from the external DC grid when the photovoltaic cell assembly does not generate electricity. When the external DC grid has no power or does not meet the grid-connection condition, the power generated by the photovoltaic cell assembly is not grid-connected and is physically isolated. In other words, when either the photovoltaic cell assembly or the DC grid loses power, the two are physically isolated, the anti-islanding function is realized, and the cost of the power supply circuit is reduced. Furthermore, the optocoupler detection circuit in the power supply circuit described above can also realize the monitoring of the external DC grid in the isolated state.

[0101] The application also provides a power utilization device. The power utilization device can include the power supply circuit according to any one of the preceding embodiments. For example, the power utilization device can be a photovoltaic water heater, an air conditioner, or any other power utilization device.

[0102] So far, the technical solution of the application has been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the application, and the technical solutions after the changes or replacements will all fall within the protection scope of the application.

Claims

1. A power supply circuit, characterized in that, The power generation device includes: a power generation component and a control module. The power supply circuit includes: a first switch module, a voltage detection module, and a second switch module. A first terminal of the first switch module is connected to the output terminal of the power generation component. A second terminal of the first switch module and a first terminal of the second switch module are both connected to the first terminal of the voltage detection module. A third terminal of the first switch module and a second terminal of the second switch module are both connected to the second terminal of the voltage detection module. A third terminal of the second switch module is connected to the input terminal of the target power grid. A third terminal of the voltage detection module is connected to the first terminal of the control module. A second terminal of the control module is connected to the fourth terminals of the first switch module and the second switch module. When the power generation component is not generating electricity, the first switch module is used to disconnect the first connection between the power generation component and the first switch module; the second switch module is used to disconnect the second connection between the target power grid and the second switch module; When the power generation component generates electricity, the voltage detection module is used to detect the voltage values ​​on both sides of the target power grid and output the voltage values ​​to the control module; the control module is used to control the first switch module to disconnect the first connection and control the second switch module to connect the second connection when the voltage value is less than the grid connection voltage threshold.

2. The power supply circuit according to claim 1, characterized in that, The first switch module includes: a first switch and a second switch, wherein a first terminal of the first switch is connected to the positive output terminal of the power generation component, and a second terminal of the first switch is connected to the first terminal of the voltage detection module; a first terminal of the second switch is connected to the negative output terminal of the power generation component, and a second terminal of the second switch is connected to the second terminal of the voltage detection module; disconnecting the first connection by the first switch module includes: both the first switch and the second switch being disconnected; And / or, The second switch module includes a third switch and a fourth switch. The first terminal of the third switch is connected to the positive input terminal of the target power grid, and the second terminal of the third switch is connected to the first terminal of the voltage detection module. The first terminal of the fourth switch is connected to the negative input terminal of the target power grid, and the second terminal of the fourth switch is connected to the second terminal of the voltage detection module. Disconnecting the second connection using the second switch module includes both the third and fourth switches being open. Connecting the second connection using the second switch module includes both the third and fourth switches being closed.

3. The power supply circuit according to claim 1 or 2, characterized in that, The voltage detection module includes: a voltage sampling unit and an isolation unit; The second terminal of the first switch module and the first terminal of the second switch module are both connected to the first terminal of the voltage sampling unit; the third terminal of the first switch module and the second terminal of the second switch module are both connected to the second terminal of the voltage sampling unit; the third terminal of the voltage sampling unit is connected to the first terminal of the isolation unit; and the second terminal of the isolation unit is connected to the first terminal of the control module. The voltage sampling unit is used to sample the voltage on both sides of the target power grid to obtain the initial voltage on both sides of the target power grid; The isolation unit is used to isolate the target power grid from the control module when the initial voltage is zero, and to determine the voltage values ​​on both sides of the target power grid based on the initial voltage.

4. The power supply circuit according to claim 3, characterized in that, The voltage sampling unit includes: a first resistor, a second resistor, and a first amplification subunit; The second terminal of the first switch module and the first terminal of the second switch module are both connected to the first terminal of the first resistor; the second terminal of the first resistor and the first terminal of the second resistor are both connected to the first terminal of the first amplification subunit; the second terminal of the first amplification subunit is connected to the first terminal of the isolation unit; the third terminal of the first switch module and the second terminal of the second switch module are both connected to the second terminal of the second resistor. The first amplification subunit is used to amplify the voltage obtained from voltage sampling from both sides of the target power grid to obtain the initial voltage.

5. The power supply circuit according to claim 4, characterized in that, The isolation unit includes: a first optocoupler diode, a second optocoupler diode, and a third optocoupler diode; The second terminal of the first amplification subunit is connected to the negative terminal of the first optocoupler diode, and the positive terminal of the first optocoupler diode is connected to the first output terminal of the target power grid; the first terminal of the first amplification subunit is connected to the negative terminal of the second optocoupler diode; the positive terminals of the second optocoupler diode and the third optocoupler diode are both grounded; the negative terminal of the third optocoupler diode is connected to the first terminal of the control module.

6. The power supply circuit according to claim 5, characterized in that, The voltage detection module further includes: a second amplification unit, wherein the negative terminal of the third optocoupler diode is connected to the first terminal of the control module through the second amplification unit; The second amplification unit is used to amplify the voltage across the third optocoupler diode to obtain the amplified voltage as the voltage value on both sides of the target power grid.

7. The power supply circuit according to claim 6, characterized in that, The third terminal of the first amplification subunit is connected to the first output terminal of the target power grid; the target power grid is used to provide the operating voltage of the first amplification subunit. The second amplification unit is also connected to the third terminal of the control module; the control module is used to provide the operating voltage of the second amplification unit.

8. The power supply circuit according to claim 1 or 2, characterized in that, When the power generation component generates electricity, the control module is also used to control the first switch module to conduct the first connection and control the second switch module to conduct the second connection when the voltage value is greater than or equal to the grid-connected voltage threshold.

9. The power supply circuit according to claim 1 or 2, characterized in that, The power generation component is a photovoltaic power generation component; the photovoltaic power generation component outputs direct current, and the target power grid is a direct current power grid.

10. An electrical appliance, characterized in that, The electrical equipment includes a power supply circuit as described in any one of claims 1-9.

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