Power supply circuit and electric equipment

Abstract

The invention belongs to the technical field of power generation, and particularly relates to a power supply circuit and electric equipment. The problem that an existing power supply circuit is poor in safety is solved. 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 the output end of the power generation assembly. The second switch module is connected with the input end of the 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, the first connection between the power generation assembly and the first switch module is disconnected; the second connection between the target power grid and the second switch module is disconnected; when the power generation assembly generates power and the voltage value, detected by the voltage detection module, of the two sides of the target power grid is smaller than a grid-connected voltage threshold value, the control module controls the first switch module to disconnect the first connection and controls the second switch module to connect the second connection. Through the arrangement, the safety of the power supply circuit is improved.

Description

Technical Field

[0001] The present application belongs to the field of power generation technology, and specifically relates to a power supply circuit and power-consuming equipment. Background Art

[0002] Green renewable energy power generation methods such as solar photovoltaic power generation (abbreviated as photovoltaic power generation) and wind power generation are gaining more and more attention. Taking photovoltaic power generation as an example, when using the existing photovoltaic power generation power supply circuit, there is a loss of electric energy (such as the power loss of the DC inversion process on the power generation side and the power loss of the AC rectification process on the power consumption side). In order to reduce the power loss of the power supply circuit, some existing implementation methods propose to directly connect the DC power output by the photovoltaic cell assembly in parallel to the power supply circuit on the power consumption equipment of the DC power grid.

[0003] However, the existing power supply circuit has a high potential safety hazard. Summary of the invention

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

[0005] 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;

[0006] 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 conduct the second connection when the voltage value is less than the grid-connected voltage threshold.

[0007] In the preferred technical solution of the power supply circuit, the first switch module includes: a first switch, and a second switch, wherein the first end of the first switch is connected to the positive electrode of the output end of the power generation component, and the second end of the first switch is connected to the first end of the voltage detection module; the first end of the second switch is connected to the negative electrode of the output end of the power generation component, and the second end of the second switch is connected to the second end of the voltage detection module; the first switch module disconnects the first connection, including: the first switch and the second switch are both disconnected;

[0008] and / or,

[0009] The second switch module includes: a third switch and a fourth switch, wherein a first end of the third switch is connected to a positive pole of an input end of the target power grid, and a second end of the third switch is connected to a first end of the voltage detection module; a first end of the fourth switch is connected to a negative pole of an input end of the target power grid, and a second end of the fourth switch is connected to a second end of the voltage detection module; disconnecting the second connection by the second switch module includes: both the third switch and the fourth switch are disconnected; and connecting the second connection by the second switch module includes: both the third switch and the fourth switch are closed.

[0010] In the preferred technical solution of the above power supply circuit, the voltage detection module includes: 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 to the 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 to the second end of the voltage sampling unit; the third end of the voltage sampling unit is connected to the first end of the isolation unit; the second end of the isolation unit is connected to the first end of the control module;

[0012] The voltage sampling unit is used to sample the voltages at both sides of the target power grid to obtain the initial voltages at both sides of the target power grid;

[0013] The isolation unit is used to isolate the target power grid from the control module when the initial voltage is zero, and determine voltage values ​​at both sides of the target power grid according to the initial voltage.

[0014] In the preferred technical solution of the above power supply circuit, the voltage sampling unit includes: a first resistor, a second resistor, and a first amplifying subunit;

[0015] The second end of the first switch module and the first end of the second switch module are both connected to the first end of the first resistor; the second end of the first resistor and the first end of the second resistor are both connected to the first end of the first amplifying subunit; the second end of the first amplifying subunit is 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 are both connected to the second end of the second resistor;

[0016] The first amplifying subunit is used to amplify the voltage obtained by sampling the voltages at both sides of the target power grid to obtain the initial voltage.

[0017] In the preferred technical solution of the above power supply circuit, the isolation unit includes: a first photocoupler diode, a second photocoupler diode, and a third photocoupler diode;

[0018] The second end of the first amplifying subunit is connected to the cathode of the first optocoupler diode, and the anode of the first optocoupler diode is connected to the first output end of the target power grid; the first end of the first amplifying subunit is connected to the cathode of the second optocoupler diode; the anode of the second optocoupler diode and the anode of the third optocoupler diode are both grounded; the cathode of the third optocoupler diode is connected to the first end of the control module.

[0019] In the preferred technical solution of the above power supply circuit, the voltage detection module further includes: a second amplifying unit, the cathode of the third optical coupling diode is connected to the first end of the control module through the second amplifying unit;

[0020] The second amplifying unit is used to amplify the voltage across the third optical coupler diode to obtain the amplified voltage as the voltage value across the target power grid.

[0021] In the preferred technical solution of the above power supply circuit, the third terminal of the first amplifying subunit is connected to the first output terminal of the target power grid; the target power grid is used to provide the first amplifying subunit with the working voltage of the first amplifying subunit;

[0022] The second amplifying unit is also connected to the third end of the control module; the control module is used to provide the second amplifying unit with an operating voltage of the second amplifying unit.

[0023] In the preferred technical solution of the above-mentioned power supply circuit, when the power generation component generates electricity, the control module is also used 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 above power supply circuit, 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.

[0025] In a second aspect, the present application provides an electrical device, wherein the electrical device comprises a power supply circuit as described in any one of the first aspects above.

[0026] It is understandable to those skilled in the art that, in the power supply circuit and power-consuming equipment provided by the present application, when the power generation component is not generating electricity, the first connection between the power generation component 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 above-mentioned power supply circuit, when the power generation component is not generating electricity, regardless of whether the target power grid has electricity, the target power grid will be physically isolated from the power generation component, thereby avoiding the situation where there is still current in the circuit between the target power grid and the power generation component, thereby improving the safety of the power supply circuit. When the power generation component generates electricity, the voltage value on both sides of the target power grid can be detected by the voltage detection module. Through the control module, when the voltage value is less than the grid-connected voltage threshold, the first switch module can be controlled to disconnect the above-mentioned first connection, and the second switch module can be controlled to conduct the above-mentioned second connection. Through the above-mentioned power supply circuit, it can be achieved that when the target power grid has no electricity or the voltage does not meet the grid-connected conditions, the power generation component is isolated from the target power grid, avoiding the problem that the power generation component is still connected to the target power grid when the target power grid loses power, thereby avoiding the risk of electric shock to the user, and improving the safety of the power supply circuit. By controlling the second switch module to conduct the above-mentioned 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, and continuously monitor the voltages on both sides of the target power grid, thereby further improving the safety of the power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The preferred implementation of the power supply circuit of the present application is described below with reference to the accompanying drawings and in combination with the power supply circuit. The accompanying drawings are:

[0028] Figure 1 It is a structural schematic diagram of an existing photovoltaic power supply circuit;

[0029] Figure 2 A schematic diagram of the structure of a power supply circuit provided in this application;

[0030] Figure 3 A schematic diagram of the structure of another power supply circuit provided in this application;

[0031] Figure 4 A schematic diagram of the structure of a voltage detection module provided in this application;

[0032] Figure 5 A schematic diagram of the structure of a voltage sampling unit provided in this application;

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

[0034] Figure 7 A schematic diagram of the structure of another power supply circuit provided in the present application. DETAILED DESCRIPTION

[0035] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the present application and are not intended to limit the scope of protection of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0036] Secondly, it should be noted that in the description of the present application, terms such as "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present application.

[0037] In addition, it should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0038] Green renewable energy power generation methods such as solar photovoltaic power generation (abbreviated as photovoltaic power generation) and wind power generation are gaining more and more attention. Taking photovoltaic power generation as an example, Figure 1 FIG. 1 is a schematic diagram of the structure of an existing photovoltaic power supply circuit. Figure 1 As shown, in the existing photovoltaic power generation power supply circuit, an inverter and an AC rectifier are connected between the photovoltaic cell assembly and the power-consuming equipment. The inverter can invert the direct current output by the photovoltaic cell assembly and then output it to the AC rectifier on the power-consuming side, so as to realize the long-distance transmission of electric energy. The AC rectifier can rectify the AC output by the inverter into DC power that can be used by the power-consuming equipment.

[0039] When using the existing photovoltaic power supply circuit, there are two processes of power loss, one is the DC inversion process on the power generation side, and the other is the AC rectification process on the power consumption side. In other words, the existing photovoltaic power supply circuit has the problem of large power loss.

[0040] In order to reduce the power loss of the power supply circuit, some existing implementations have also proposed a method of directly connecting the direct current output by the photovoltaic cell assembly in parallel to the power consumption equipment of the direct current grid.

[0041] However, when using the existing power supply circuit, if the DC grid loses power (for example, for maintenance), the user (for example, circuit maintenance personnel) may be electrocuted because the photovoltaic cell assembly is still connected to the DC grid. When the photovoltaic cell assembly is not generating electricity, if the DC grid has other power supplies, current may still exist in the circuit between the DC grid and the photovoltaic cell group, thus posing a safety hazard.

[0042] Taking into account the above-mentioned problems existing in the existing power supply circuit, the present application proposes a power supply circuit in which there is no power transmission in the power supply circuit when the power consumption side is powered off or the power generation side is not generating electricity, so as to improve the safety of the power supply circuit.

[0043] The technical solution of the present application is described in detail below in conjunction with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail 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 switch module, a voltage detection module, and a second switch module. Among them, the first end of the first switch module can be connected to the output end of the power generation component. The second end of the first switch module and the first end of the second switch module can both be connected to the first end of the voltage detection module. The third end of the first switch module and the second end of the second switch module are both connected to the second end of the voltage detection module. The third end of the second switch module can be connected to the input end of the target power grid. The third end of the voltage detection module can be connected to the first end of the control module. The second end of the control module can be connected to the fourth end of the first switch module and the fourth end of the second switch module.

[0045] It should be understood that the present application does not limit the type of the above power generation component. Exemplarily, the power generation component can be, for example, a photovoltaic power generation component, or a wind power generation component or any other existing power generation component.

[0046] Optionally, taking the above-mentioned power generation component as a photovoltaic power generation component as an example, the output of the photovoltaic power generation component can be direct current. The corresponding above-mentioned target power grid can be a direct current power grid. When the target power grid is a direct current power grid, the power-consuming equipment in the direct current power grid can be direct current power-consuming equipment. Exemplarily, the direct current power-consuming equipment can be any power-consuming equipment such as a water heater, an air conditioner, etc., and this application does not limit this. In this implementation, the power generation component can be directly connected in parallel to both sides of the direct current power grid without the need for inversion or rectification, thereby reducing power loss.

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

[0048] For example, Figure 2 As shown, the connection between the first end of the first switch module and the output end of the power generation component may include, for example: the positive electrode connection end in the first end of the first switch module is connected to the positive electrode of the output end of the power generation component. The negative electrode connection end in the first end of the first switch module is connected to the negative electrode of the output end of the power generation component.

[0049] For example, Figure 2 As shown, the connection between the third terminal of the second switch module and the input terminal of the target power grid may include, for example: the positive connection terminal in the third terminal of the second switch module is connected to the positive pole of the input terminal of the target power grid. The negative connection terminal in the third terminal of the second switch module is connected to the negative pole of the input terminal of the target power grid.

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

[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] Exemplarily, taking the above-mentioned power generation component providing the control module with a working voltage as an example, when the power generation component is not generating electricity, the above-mentioned control module is powered off. After the control module is powered off, the first switch module and the second switch module can be restored to an initial state. Among them, the initial state can be that the above-mentioned first connection is disconnected, and the above-mentioned second connection is disconnected. Through the above-mentioned method, it is achieved that regardless of whether the target power grid has electricity, 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] When the power generation component generates electricity, the voltage detection module can be used to detect the voltage value on both sides of the target power grid and output the voltage value to the control module. The control module can be used to control the first switch module to disconnect the first connection and control the second switch module to conduct the second connection when the voltage value is less than the grid voltage threshold.

[0054] It should be understood that the present application does not limit the number of electrical devices included in the target power grid, nor the types of electrical devices (such as air conditioners, water heaters, etc.).

[0055] Optionally, if the above voltage value is less than the grid-connected voltage threshold, it means that the target grid has no electricity or the voltage does not meet the grid-connected conditions. Therefore, by controlling the first switch module to disconnect the above first connection when the voltage value on both sides of the target grid is less than the grid-connected voltage threshold, the power generation component is isolated from the target grid, thereby avoiding the problem that the power generation component is still connected to the target grid when the target grid loses power, thereby avoiding the risk of electric shock to the user and improving the safety of the power supply circuit. By controlling the second switch module to conduct the above second connection, the control module can continue to determine whether the voltage value on both sides of the target grid is less than the grid-connected voltage threshold, and continue to monitor the voltage on both sides of the target grid, further improving the safety of the power supply circuit.

[0056] Exemplarily, the above-mentioned grid-connected voltage threshold may be pre-stored in the control module, for example.

[0057] In this embodiment, when the power generation component is not generating electricity, the first connection between the power generation component 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 above-mentioned power supply circuit, when the power generation component is not generating electricity, regardless of whether the target power grid has electricity, the target power grid will be physically isolated from the power generation component, thereby avoiding the situation where there is still current in the circuit between the target power grid and the power generation component, thereby improving the safety of the power supply circuit. When the power generation component is generating electricity, the voltage value on both sides of the target power grid can be detected by the voltage detection module. Through the control module, when the voltage value is less than the grid voltage threshold, the first switch module can be controlled to disconnect the above-mentioned first connection, and the second switch module can be controlled to conduct the above-mentioned second connection. Through the above-mentioned power supply circuit, when the target power grid has no electricity or the voltage does not meet the grid connection conditions, the power generation component can be isolated from the target power grid, avoiding the problem that the power generation component is still connected to the target power grid when the target power grid loses power, thereby avoiding the risk of electric shock to the user, and improving the safety of the power supply circuit. By controlling the second switch module to conduct the above-mentioned 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, and continuously monitor the voltages on both sides of the target power grid, thereby further improving the safety of the power supply circuit.

[0058] As a possible implementation, when the power generation component generates electricity, the control module can also be used 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 means that the target grid voltage meets the grid-connected condition. Then, the first connection and the second connection in the power supply circuit are turned on, so that the target grid is powered by the power generation component.

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

[0061] As a possible implementation, Figure 3 This is a schematic diagram of another power supply circuit provided in this application. Figure 3 As shown (it should be understood Figure 3 The control module is not shown in the figure), the first switch module may include: a first switch, and a second switch. The first end of the first switch may be connected to the positive electrode of the output end of the power generation component. The second end of the first switch may be connected to the first end of the voltage detection module. The first end of the second switch may be connected to the negative electrode of the output end of the power generation component. The second end of the second switch may be connected to the second end of the voltage detection module.

[0062] In this implementation, the aforementioned first switch module disconnecting the first connection may include: both the first switch and the second switch are disconnected. That is, when the power generation component is not generating electricity, the first switch and the second switch may both be disconnected. When the power generation component is generating electricity, and the voltage value on both sides of the target power grid is less than the grid-connected voltage threshold, the first switch and the second switch remain disconnected. When the power generation component is generating electricity, and the above voltage value is greater than or equal to the above grid-connected voltage threshold, optionally, the first switch and the second switch may be closed to conduct the above first connection.

[0063] The first switch and the second switch in the first switch module provide a foundation for disconnecting the first connection and conducting the first connection, thereby providing a foundation for improving the safety of the power supply circuit.

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

[0065] In this implementation, the second switch module disconnecting the second connection may include: both the third switch and the fourth switch are disconnected. The second switch module connecting the second connection may include: both the third switch and the fourth switch are closed.

[0066] That is, when the power generation component is not generating electricity, the third switch and the fourth switch may both be opened. When the power generation component is generating electricity, and the voltage values ​​on both sides of the target power grid are less than the grid-connected voltage threshold, the third switch and the fourth switch may be switched to a closed state. When the power generation component is generating electricity, and the voltage value is greater than or equal to the grid-connected voltage threshold, optionally, the first switch and the second switch may remain in a closed state to conduct the second connection.

[0067] The third switch and the fourth switch in the second switch module provide a foundation for disconnecting the second connection and conducting the second connection, thereby providing a foundation for improving the safety of the power supply circuit.

[0068] The structure of the voltage detection module is described in detail below:

[0069] Figure 4 This is a schematic diagram of the structure of a voltage detection module provided in this application. Figure 4 As shown, as a possible implementation, the voltage detection module may include: a voltage sampling unit, and an isolation unit.

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

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

[0072] Figure 5 This is a schematic diagram of the structure of a voltage sampling unit provided in this application. Figure 5 As shown, in some embodiments, the voltage sampling unit may include: a first resistor, a second resistor, and a first amplifying subunit.

[0073] Wherein, the second end of the first switch module and the first end of the second switch module may 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 may be connected to the first end of the first amplifying subunit. The second end of the first amplifying subunit may 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 may be connected to the second end of the second resistor.

[0074] The first resistor and the second resistor may be used as sampling resistors for sampling voltages from both sides of the target power grid. The first amplifying subunit may be used to amplify the voltages obtained by sampling voltages from both sides of the target power grid to obtain the initial voltage.

[0075] Exemplarily, the first amplifying subunit may be any existing operational amplifier, which is not limited in the present application. The resistance value of the first resistor, the resistance value of the second resistor, the voltage amplification factor of the first amplifying subunit, etc. are not limited in the present application.

[0076] Through the first resistor and the second resistor, the power supply circuit can sample voltage from both sides of the target power grid. The sampled voltage can be amplified by the first amplifying subunit, and the initial voltage can be input to the isolation unit after being obtained, so that the isolation unit can 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 isolation unit can be used to isolate the target power grid from the control module when the initial voltage is zero, and determine the voltage values ​​at both sides of the target power grid according to the initial voltage.

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

[0079] The second end of the first amplifying subunit may be connected to the cathode of the first optocoupler diode. The anode of the first optocoupler diode may be connected to the first output end of the target power grid. The first end of the first amplifying subunit may be connected to the cathode of the second optocoupler diode. The anode of the second optocoupler diode and the anode of the third optocoupler diode may both be grounded. The cathode of the third optocoupler diode may be connected to the first end of the control module.

[0080] The anode of the first optocoupler diode is connected to the first output terminal of the target power grid, so that the target power grid can provide a positive working voltage for 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 through a voltage conversion module. The voltage conversion module can convert the voltage of the first output terminal of the target power grid into the working voltage required by the anode of the first optocoupler diode.

[0081] Through the above-mentioned isolation unit, the first optocoupler diode and the second optocoupler diode generate brightness of different intensities according to the voltage change on both sides of the target power grid. The third optocoupler diode can generate currents of different magnitudes according to the brightness, so that the magnitude of the voltage value input to the control module changes with the magnitude of the current. When the initial voltage is zero, the first optocoupler diode and the second optocoupler diode are not lit, so that the voltage across the third optocoupler diode is zero, and therefore the magnitude of the voltage value input to the control module is zero, thereby isolating the target power grid from the control module (that is, isolating the target power grid from the control module when the target power grid loses power), 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 values ​​on both sides of the target power grid based on the initial voltage" through other existing circuits, for example, and the present application does not limit this.

[0083] In some embodiments, the voltage detection module may further include: a second amplifying unit, the cathode of the third photocoupler diode is connected to the first end of the control module through the second amplifying unit;

[0084] The second amplifying unit is used to amplify the voltage across the third optical coupling diode to obtain the amplified voltage as the voltage value across the target power grid.

[0085] Through the above-mentioned second amplification unit, the voltage across the third optocoupler diode can be 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 judge whether the voltage value is less than the grid-connected voltage threshold based on the amplified voltage, thereby improving the accuracy of the control module in making the judgment, and further improving the accuracy of the control module in controlling the above-mentioned first switch module and the second switch module based on the judgment result, thereby further improving the safety of the power supply circuit.

[0086] Alternatively, in some embodiments, the cathode of the third optocoupler diode of the isolation unit may also be directly connected to the first end of the control module, for example.

[0087] In some embodiments, the third terminal of the first amplifying subunit may be connected to the first output terminal of the target power grid. The target power grid may be used to provide the first amplifying subunit with an operating voltage of the first amplifying subunit. The second amplifying unit may also be connected to the third terminal of the control module. The control module may be used to provide the second amplifying unit with an operating voltage of the second amplifying unit.

[0088] Optionally, the third terminal of the first amplifying subunit may be directly connected to the first output terminal of the target power grid, for example. Alternatively, the third terminal of the first amplifying subunit may also be connected to the first output terminal of the target power grid via a voltage conversion module, etc. The voltage conversion module may convert the voltage value of the first output terminal of the target power grid into the operating voltage of the first amplifying subunit, so that the first amplifying subunit can operate.

[0089] Optionally, the second amplifying unit may be directly connected to the third terminal of the control module. Alternatively, the second amplifying unit may also be connected to the third terminal of the control module via a voltage conversion module, etc. The voltage conversion module may convert the voltage value of the third terminal of the control module into an operating voltage of the second amplifying unit, so that the second amplifying unit can operate.

[0090] In this 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. The voltage value on both sides of the target power grid is determined by the initial voltage, and the voltage value can be output to the control module to realize the monitoring of the target power grid in the isolated state.

[0091] For example, the target power grid is a DC power grid, the power generation component is a photovoltaic power generation component, and the control module can also be called a control system. Figure 7 This is a schematic diagram of the structure of another power supply circuit provided by the present application. Figure 7 As shown, DC+ represents the positive output terminal of the power generation component; DC- represents the negative output terminal of the power generation component. DC_O+ represents the positive pole of the DC grid; DC_O- represents the negative pole of the DC grid. V DC O is the first terminal of the control module.

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

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

[0094] In addition, the Vcc' terminal of U2 is connected to the first output terminal of the target power grid. The target power grid can be used to provide the first amplifier subunit with the working voltage of the first amplifier subunit (or the DC power grid can be used as the primary working power supply of U3). The 5V interface of U1 is the positive electrode of the first optocoupler diode, which can be connected to the first output terminal of the target power grid. The Vcc terminal of U3 can be connected to the third terminal of the control module. The control module can be used to provide the working voltage for U3.

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

[0096] Based on Figure 7 In the power supply circuit shown, when the photovoltaic cell assembly is not generating electricity, the control system (that is, the aforementioned control module) has no power, and K1 to K4 are all disconnected in the initial state, and will be physically disconnected from the photovoltaic cell assembly and the control system 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, keeping K1 and K2 open and closing K3 and K4. The optocoupler primary of the linear optocoupler can work (the diode is on) or not work (the diode is not on) depending on whether there is power in the external DC grid.

[0098] If the external DC grid (that is, the DC grid) has no power or the voltage does not meet the grid-connected conditions (that is, the aforementioned voltage value is less than the grid-connected voltage threshold), K1 and K2 are disconnected, K3 and K4 are closed, and the control system continues to monitor the state of the external DC grid until the voltage values ​​on both sides of the DC grid meet the grid-connected conditions.

[0099] If the external DC grid voltage reaches the grid-connected 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 controlled by the control system and connected to the external DC grid.

[0100] In this embodiment, the above-mentioned four-switch isolation circuit topology is used to achieve physical isolation from the external DC power grid when the photovoltaic cell assembly is not generating electricity. When the external DC power grid is out of power or does not meet the grid connection conditions, the electricity generated by the photovoltaic cell assembly is not connected to the grid and physical isolation is achieved. In other words, when either the photovoltaic cell assembly or the DC power grid loses power, the two sides are physically isolated, an anti-islanding function is achieved, and the cost of the power supply circuit is reduced. Furthermore, the optocoupler detection circuit in the above-mentioned power supply circuit can also realize the monitoring of the external DC power grid in the isolated state.

[0101] The present application also provides an electrical device. The electrical device may include the power supply circuit described in any of the above embodiments. Exemplarily, the electrical device may be any electrical device such as a photovoltaic water heater, an air conditioner, etc., and the present application does not limit this.

[0102] So far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A power supply circuit, characterized in that: The power generation device includes: a power generation component and a control module, and the power supply circuit includes: a first switch module, a voltage detection module, and a second switch module; the first end of the first switch module is connected to the output end of the power generation component; the second end of the first switch module and the first end of the second switch module are both connected to the first end of the voltage detection module, and the third end of the first switch module and the second end of the second switch module are both connected to the second end of the voltage detection module; the third end of the second switch module is connected to the input end of the target power grid; the third end of the voltage detection module is connected to the first end of the control module, and the second end of the control module is connected to the fourth end of the first switch module and the fourth end of 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 conduct the second connection when the voltage value is less than the grid-connected 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 end of the first switch is connected to the positive electrode of the output end of the power generation component, and a second end of the first switch is connected to the first end of the voltage detection module; a first end of the second switch is connected to the negative electrode of the output end of the power generation component, and a second end of the second switch is connected to the second end of the voltage detection module; the first switch module disconnects the first connection, including: both the first switch and the second switch are disconnected; and / or, The second switch module includes: a third switch and a fourth switch, wherein a first end of the third switch is connected to a positive pole of an input end of the target power grid, and a second end of the third switch is connected to a first end of the voltage detection module; a first end of the fourth switch is connected to a negative pole of an input end of the target power grid, and a second end of the fourth switch is connected to a second end of the voltage detection module; disconnecting the second connection by the second switch module includes: both the third switch and the fourth switch are disconnected; and connecting the second connection by the second switch module includes: both the third switch and the fourth switch are 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 end of the first switch module and the first end of the second switch module are both connected to the 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 to the second end of the voltage sampling unit; the third end of the voltage sampling unit is connected to the first end of the isolation unit; the second end of the isolation unit is connected to the first end of the control module; The voltage sampling unit is used to sample the voltages at both sides of the target power grid to obtain the initial voltages at 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 determine voltage values ​​at both sides of the target power grid according to 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 amplifying subunit; The second end of the first switch module and the first end of the second switch module are both connected to the first end of the first resistor; the second end of the first resistor and the first end of the second resistor are both connected to the first end of the first amplifying subunit; the second end of the first amplifying subunit is 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 are both connected to the second end of the second resistor; The first amplifying subunit is used to amplify the voltage obtained by sampling the voltages at 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 photocoupler diode, a second photocoupler diode, and a third photocoupler diode; The second end of the first amplifying subunit is connected to the cathode of the first optocoupler diode, and the anode of the first optocoupler diode is connected to the first output end of the target power grid; the first end of the first amplifying subunit is connected to the cathode of the second optocoupler diode; the anode of the second optocoupler diode and the anode of the third optocoupler diode are both grounded; the cathode of the third optocoupler diode is connected to the first end of the control module.

6. The power supply circuit according to claim 5, characterized in that: The voltage detection module further includes: a second amplifying unit, through which the cathode of the third optical coupling diode is connected to the first end of the control module; The second amplifying unit is used to amplify the voltage across the third optical coupler diode to obtain the amplified voltage as the voltage value across the target power grid.

7. The power supply circuit according to claim 6, characterized in that: The third terminal of the first amplifying subunit is connected to the first output terminal of the target power grid; the target power grid is used to provide the first amplifying subunit with an operating voltage of the first amplifying subunit; The second amplifying unit is also connected to the third end of the control module; the control module is used to provide the second amplifying unit with an operating voltage of the second amplifying 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 further 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 device, characterized in that: The electrical equipment comprises the power supply circuit as described in any one of claims 1 to 9.

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