Load access identification detection circuit and energy storage device

Abstract

The application provides a load access identification detection circuit and an energy storage device. The load access identification detection circuit is suitable for an alternating current output module and comprises a power supply unit, a first switch unit, a first voltage division unit, a second voltage division unit, a sampling unit and a control unit. After a load is connected, the connected load and the first voltage division unit, the second voltage division unit and the first discharge unit and the second discharge unit form a voltage division circuit to jointly divide voltage, so that the voltage on the second voltage division unit changes when the load is connected or not connected, and the sampling voltage value also changes according to whether the load is connected or not. Therefore, no matter what type of load the alternating current output module is connected to, the control unit can confirm whether the alternating current output module is connected to a load according to the sampling voltage value, without the need to provide different load access identification detection circuits for different types of loads, thereby effectively reducing the cost of load identification.

Description

Technical Field

[0001] This application relates to the field of load identification technology, specifically to a load access identification and detection circuit and an energy storage device. Background Technology

[0002] In related technologies, mobile energy storage devices are typically equipped with an AC output switch. When a user needs AC power, they manually close the AC output switch to allow the mobile energy storage device to output AC power. When AC power is not needed, they manually open the AC output switch to stop the mobile energy storage device from outputting AC power, thus preventing no-load losses caused by outputting AC power under no-load conditions, and even potential electrical safety issues. However, manually controlling AC power supply can negatively impact the user experience.

[0003] To improve safety and user experience, it's necessary to automatically detect and identify the load connection status of the AC output interface of mobile energy storage devices, thereby automatically controlling the AC power output based on the identification results. Currently, the common practice is to modify the physical structure of the AC output interface by adding physical identification to the interface. Based on the identification result, an electrical signal is generated, allowing the mobile energy storage device to identify whether a load is connected to the AC output interface. However, AC output interfaces come in various types and can even be compatible with different socket types of loads. Therefore, multiple different detection circuits are needed to detect load insertion. Clearly, this approach is too costly and the circuitry is too complex. Summary of the Invention

[0004] In view of this, this application provides a load access identification and detection circuit and an energy storage device, which can realize load access identification when any type of load is accessed without setting up multiple detection circuits, thereby reducing the cost of load access identification for AC output modules.

[0005] This application provides a load access identification and detection circuit suitable for an AC output module. The AC output module includes a first live wire terminal, a second live wire terminal, a neutral wire terminal, a first discharge unit, and a second discharge unit. The first live wire terminal, the second live wire terminal, and the neutral wire terminal are used to connect to a load. The first discharge unit is connected between the first live wire terminal and the neutral wire terminal. The second discharge unit is connected between the second live wire terminal and the neutral wire terminal. The load access identification and detection circuit includes a power supply unit, a first switching unit, a first voltage divider unit, a second voltage divider unit, a sampling unit, and a control unit. The output terminal of the power supply unit is connected to the first terminal of the first switching unit. The second end of the first switching unit is used to connect to one of the first live wire terminal and the second live wire terminal; the first voltage divider unit is connected between the first live wire terminal and the second live wire terminal; the second voltage divider unit is connected between the neutral wire terminal and ground; the sampling unit is connected to the second voltage divider unit and is used to collect the voltage on the second voltage divider unit and output the sampled voltage value; the control unit is connected to the output terminal of the sampling unit and to the control terminal of the first switching unit; the control unit is used to turn on the first switching unit when performing a load access identification operation, and determine whether the AC output module is connected to a load based on the change of the sampled voltage value.

[0006] In the above embodiment, when the control unit performs the load access identification operation, it controls the first switching unit to turn on. The power supply unit provides voltage to the voltage divider circuit formed by the first voltage divider unit, the second voltage divider unit, and the first and second bleeder units in the AC output module. The sampling unit collects the voltage on the second voltage divider unit and outputs the sampled voltage value. When the AC output module is connected to different types of loads, the connected load and the voltage divider circuit perform voltage division together, causing the voltage on the second voltage divider unit to change when there is a load connected and when there is no load connected. The sampled voltage value also changes depending on whether there is a load connected. Therefore, regardless of the type of load connected to the AC output module, the control unit can confirm whether the AC output module is connected to a load based on the sampled voltage value. This eliminates the need to set up a corresponding load access detection circuit for each type of load access, simplifies the load access identification circuit structure, and effectively reduces the cost of load identification for the AC output module.

[0007] In one embodiment, the control unit is further configured to connect to an inverter unit, the input terminal of which is configured to receive DC power, and the output terminal of which is connected to the first live wire terminal, the second live wire terminal, and the neutral wire terminal; the control unit is further configured to: when it is determined that the AC output module is connected to the load, control the inverter unit to work to convert the DC power into AC power to power the load; and when it is determined that the AC output module is not connected to the load, control the inverter unit to stop working.

[0008] In one embodiment, the load access identification and detection circuit further includes multiple second switching units, wherein the first live wire terminal, the second live wire terminal, and the neutral wire terminal are respectively connected to the output terminal of the inverter unit through at least one second switching unit; the control unit is further configured to: when it is determined that the AC output module is connected to a load, determine the connection state between the load and the first live wire terminal, the second live wire terminal, and the neutral wire terminal based on the sampled voltage value; and control the corresponding second switching unit to turn on according to the connection state, so as to provide the AC power converted by the inverter unit to the load.

[0009] In one embodiment, the control unit is further configured to: after determining that the AC output module has an access load based on the change in the sampled voltage value, control the first switching unit to disconnect.

[0010] In one embodiment, the power supply unit includes a flyback circuit. The input terminal of the flyback circuit is connected to a DC bus or a power supply to receive DC power. The output terminal of the flyback circuit is connected to the first terminal of the first switching unit. The flyback circuit is used to convert the DC power into voltage and provide the converted voltage to the first live wire terminal or the second live wire terminal.

[0011] In one embodiment, the control unit is further configured to: detect the output power of the inverter unit; when the output power is lower than a preset threshold, control the inverter unit to stop working and perform the load access identification operation; when it is determined that the AC output module is connected to the load, control the inverter unit to work again to supply power to the load.

[0012] In one embodiment, the control unit is further configured to: when the output power is lower than a preset threshold and it is determined that the AC output module is connected to the load, perform the load access identification operation at a preset time interval until the number of times the load access identification operation is performed is greater than a preset number or the output power is greater than the preset threshold.

[0013] In one embodiment, the control unit is further configured to: reset the number of load access identification operations to zero when the number of load access identification operations exceeds a preset number or the output power exceeds the preset threshold.

[0014] In one embodiment, the first discharge unit, the second discharge unit, the first voltage divider unit, and the second voltage divider unit have different impedances.

[0015] A second aspect of this application provides an energy storage device, including an AC output module and a load access identification and detection circuit as described above. Attached Figure Description

[0016] Figure 1 This is a functional module diagram of the AC output module and the load access identification and detection circuit provided in the embodiments of this application.

[0017] Figure 2 This is a functional module diagram of the AC output module and the load access identification and detection circuit provided in another embodiment of this application.

[0018] Figure 3 This is a functional module diagram of the AC output module and the load access identification and detection circuit provided in another embodiment of this application.

[0019] Figure 4 This is a schematic diagram of the circuit structure of an AC output module and a load access identification and detection circuit provided in an embodiment of this application.

[0020] Figure 5 This is a schematic diagram of the equivalent circuit structure of the AC output module connected to an L1 / N type load in an embodiment of this application.

[0021] Figure 6 This is a schematic diagram of the equivalent circuit structure of the AC output module connected to an L2 / N type load in an embodiment of this application.

[0022] Figure 7 This is a schematic diagram of the equivalent circuit structure of the AC output module connected to an L1 / L2 type load in an embodiment of this application.

[0023] Figure 8 This is a schematic diagram of the functional modules of an energy storage device provided in an embodiment of this application. Detailed Implementation

[0024] It should be noted that the terms "first" and "second" in the specification, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0025] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0026] Some embodiments will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] In mobile energy storage devices equipped with AC output interfaces, to improve the safety of use and enhance the user experience, it is necessary to automatically detect and identify the load connected to the AC output interface, and then automatically control the AC power output based on the identification results. It can be understood that mobile energy storage devices can be purely energy storage devices, or they can be electronic devices with energy storage functions, such as air conditioners, refrigerators, and self-moving devices with battery packs.

[0028] Currently, by adding physical identification to the AC output interface of mobile energy storage devices, and generating an electrical signal based on the identification result, the mobile energy storage device can identify whether a load is connected to the AC output interface based on the electrical signal. The AC output interface of mobile energy storage devices can be of various types, or it can be compatible with various types of sockets. In this case, multiple detection circuits are needed to realize the insertion detection of the load, which is too costly and the circuitry is quite complex.

[0029] To address this, this application provides a load access identification and detection circuit that enables load access identification when any type of load is connected to the AC output module, thereby reducing the cost of load access identification for AC output modules.

[0030] Next, with reference to the accompanying drawings, we will describe the load access identification and detection circuit provided in this application. This load access identification and detection circuit is applicable to AC output modules and is used to identify whether a load is connected to the AC output module. In some embodiments, the load identification and detection circuit provided in this application can be disposed in an energy storage device having an AC output module.

[0031] Please see Figure 1 , Figure 1This is a functional block diagram of an AC output module 10 and a load access identification and detection circuit 20 provided in an embodiment of this application. Specifically, the AC output module 10 includes a first live wire terminal L1, a second live wire terminal L2, a neutral wire terminal N, a first discharge unit 11, and a second discharge unit 12. The first live wire terminal L1, the second live wire terminal L2, and the neutral wire terminal N are used for connection to a load. The first discharge unit 11 is connected between the first live wire terminal L1 and the neutral wire terminal N. The second discharge unit 12 is connected between the second live wire terminal L2 and the neutral wire terminal N.

[0032] The AC output module 10 may include multiple AC output interfaces of different types. The first live wire terminal L1, the second live wire terminal L2, and the neutral wire terminal N can be connected to different types of AC output interfaces through different connecting wires. For example, the AC output interface types may be L1 / N / PE type interface, L1 / N type interface, L2 / N / PE type interface, L2 / N type interface, L1 / L2 / N type interface, L1 / L2 / N / PE type interface, etc., to adapt to corresponding types of loads. For example, the L1 / N / PE type interface adapts to loads with L1 / N / PE type plugs, and the L2 / N / PE type interface adapts to loads with L2 / N / PE type plugs, etc.

[0033] Of course, the AC output module 10 may also include only one type of AC output interface, such as an L1 / L2 / N / PE type interface. This AC output interface is also compatible with loads with L1 / N type plugs, loads with L2 / N type plugs, and loads with L1 / L2 type plugs, etc. In this embodiment, the load access identification and detection circuit 20 can identify the load access of the AC output module 10 for any of the above types of loads, thereby reducing the cost of load access identification.

[0034] The load access identification and detection circuit 20 includes a power supply unit 21, a first switching unit 22, a first voltage divider unit 23, a second voltage divider unit 24, a sampling unit 25, and a control unit 26.

[0035] The output terminal of the power supply unit 21 is connected to the first terminal of the first switching unit 22. The second terminal of the first switching unit 22 is used to connect to one of the first live wire terminals L1 and L2. Figure 1 For example, the second end of the first switch unit 22 is used to connect to the first live wire terminal L1.

[0036] The first voltage divider unit 23 is connected between the first live wire terminal L1 and the second live wire terminal L2, and the second voltage divider unit 24 is connected between the neutral wire terminal N and ground. The sampling unit 25 is connected to the second voltage divider unit 24 and is used to acquire the voltage on the second voltage divider unit 24 and output the sampled voltage value. The first discharge unit 11, the second discharge unit 12, the first voltage divider unit 23, and the second voltage divider unit 24 can have different impedances, thereby forming different voltage division voltages.

[0037] The control unit 26 is connected to the output terminal of the sampling unit 25 and to the control terminal of the first switching unit 22. The control unit 26 is used to turn on the first switching unit 22 when performing a load connection identification operation, and to determine whether the AC output module 10 is connected to a load based on changes in the sampled voltage value. The first switching unit 22 may include a controllable switch, such as a relay, a switching transistor, etc.

[0038] In this embodiment, the control unit 26 in the load access identification and detection circuit 20 controls the first switching unit 22 to turn on when performing the load access identification operation. The power supply unit 21 provides voltage to the voltage divider circuit formed by the first voltage divider unit 23, the second voltage divider unit 24, and the first discharge unit 11 and the second discharge unit 12 in the AC output module 10. The sampling unit 25 collects the voltage on the second voltage divider unit 24 and outputs the sampled voltage value. When the AC output module 10 is connected to different types of loads, the connected load and the voltage divider circuit perform voltage division together, so that the voltage on the second voltage divider unit 24 will change when there is a load connected and when there is no load connected. The sampled voltage value will also change depending on whether there is a load connected. Therefore, no matter what type of load is connected to the AC output module 10, the control unit 26 can confirm whether the AC output module 10 is connected to a load based on the sampled voltage value. Thus, it is not necessary to set up a corresponding load access detection circuit for each type of load access, simplifying the load access identification circuit structure. Therefore, the load access identification and detection circuit 20 in this embodiment has a simple structure and can effectively reduce the cost of load identification of the AC output module 10.

[0039] In one embodiment, the voltage division ratio of the first voltage divider unit 23 and the second voltage divider unit 24 can be set so that the voltage on the sampling unit 25 has a certain voltage change threshold when there is a load connected and when there is no load connected. This allows for accurate identification of whether there is a load connected based on the voltage, thereby avoiding misjudgment due to small voltage changes and improving the accuracy of load connection identification.

[0040] In this embodiment, when the AC output module 10 includes multiple AC output interfaces of different types, the control unit 26 of the load access identification and detection circuit 20 can identify whether a load is connected to the AC output module 10 based on the sampled voltage value, regardless of which AC output interface is connected to a load. Similarly, when the AC output module 10 includes only one type of AC output interface, the control unit 26 of the load access identification and detection circuit 20 can identify whether a load is connected based on the sampled voltage value, regardless of the type of load connected to that AC output interface.

[0041] Understandably, the control unit 26 can also be used to control the first switching unit 22 to disconnect after determining that the AC output module 10 has a load connected based on changes in the sampled voltage value. After the first switching unit 22 is disconnected, the power supply unit 21 no longer provides voltage to the first live wire terminal L1 or the second live wire terminal L2, so the second voltage divider unit 24 has no voltage, and thus the sampled voltage value output by the sampling unit 25 is 0. The control unit 26 then stops performing the load connection identification operation. This prevents the control unit 26 from repeatedly performing the load connection identification operation after determining that the AC output module 10 has a load connected, thereby reducing power consumption.

[0042] In some embodiments, such as Figure 2 As shown, the control unit 26 can also be connected to the inverter unit 30. The input terminal of the inverter unit 30 is used to receive DC power, and the output terminal of the inverter unit 30 is connected to the first live wire terminal L1, the second live wire terminal L2, and the neutral wire terminal N. The control unit 26 is also used to control the inverter unit 30 to operate to convert DC power to AC power to supply power to the load when it is determined that the AC output module 10 is connected to a load. When it is determined that the AC output module 10 is not connected to a load, the control unit 26 controls the inverter unit 30 to stop operating to reduce power consumption.

[0043] Therefore, after determining whether the AC output module 10 is connected to a load based on the sampled voltage value, the control unit 26 can control whether the inverter unit 30 operates according to the load connection status. Specifically, when a load is detected, the inverter unit 30 is controlled to operate to supply power to the load; when no load is detected, the inverter unit 30 is controlled to stop operating to prevent power loss due to no-load AC output. Based on this design, it can automatically identify whether the AC output module 10 is connected to a load and automatically control the AC output of the inverter unit 30 based on the identification result, thereby improving the user experience and power safety.

[0044] It is understandable that when the inverter unit 30 stops working, the first discharge unit 11 and the second discharge unit 12 can also provide a discharge path for the electrical energy stored in the inverter unit 30 to improve the safety of the circuit.

[0045] Further, please refer to Figure 3 The load connection identification and detection circuit 20 may further include multiple second switching units. These multiple second switching units include second switching unit 27a, second switching unit 27b, and second switching unit 27c. The first live wire terminal L1, the second live wire terminal L2, and the neutral wire terminal N are respectively connected to the output terminal of the inverter unit 30 via second switching units 27a, second switching unit 27b, and second switching unit 27c. Based on this, the control unit 26 is also used to determine the connection state between the load and the first live wire terminal L1, the second live wire terminal L2, and the neutral wire terminal N based on the sampled voltage value when it is determined that the AC output module 10 is connected to a load, and then control the corresponding second switching units 27a, second switching unit 27b, and second switching unit 27c to conduct according to the connection state, so as to provide the AC power converted by the inverter unit 30 to the load.

[0046] Different types of loads have different equivalent impedances when connected to the AC output module. Furthermore, the voltage division methods between the load and the first voltage divider unit 23, the second voltage divider unit 24, the first bleeder unit 11, and the second bleeder unit 12 are also different. Therefore, the voltage across the second voltage divider unit 24, i.e., the corresponding sampled voltage value, will vary depending on the type of load connected. The control unit 26 can then determine the type of load connected based on the sampled voltage value, and determine the connection status between the load and the first live wire terminal L1, the second live wire terminal L2, and the neutral wire terminal N. Based on the determined connection status, it controls the switching on and off of the corresponding second switch units 27a, 27b, and 27c, thereby enabling the inverter unit 30 to supply power to the load through the conducting second switch units, thus reducing the no-load loss of the inverter unit 30.

[0047] Figure 4 This is a circuit diagram of a specific embodiment. (Participate) Figure 4 In this embodiment, the second switch unit 27a includes a second controllable switch K2, the second switch unit 27b includes a third controllable switch K3, and the second switch unit 27c includes a fourth controllable switch K4.

[0048] When the load is determined to be a load type with an L1 / L2 type plug, that is, the load is connected to the first live wire terminal L1 and the second live wire terminal L2, the control unit 26 controls the second controllable switch K2 and the third controllable switch K3 connected to the first live wire terminal L1 and the second live wire terminal L2 to be turned on. When the load is determined to be a load type with an L1 / N type plug pair, that is, the load is connected to the first live wire terminal L1 and the neutral wire terminal N, the control unit 26 controls the second controllable switch K2 connected to the first live wire terminal L1 and the neutral wire terminal N to be turned on. When the load is determined to be a load type with an L2 / N type plug, that is, the load is connected to the second live wire terminal L2 and the neutral wire terminal N, the control unit 26 controls the third controllable switch K3 connected to the second live wire terminal L2 and the neutral wire terminal N to be turned on.

[0049] It is understandable that the second switching unit may include a controllable switch, such as a relay, a switching transistor, etc.

[0050] In one embodiment, the first live wire terminal L1, the second live wire terminal L2, and the neutral wire terminal N are respectively connected to the output terminal of the inverter unit 30 through two second switching units. The two second switching units are connected in series. When it is necessary to disconnect the corresponding line, only one of the second switching units needs to be turned off, thereby preventing the problem of circuit shutdown failure when one of the second switching units fails, and improving the safety performance and reliability of the circuit.

[0051] In some embodiments, when the inverter unit 30 is operating, the control unit 26 is also used to detect the output power of the inverter unit 30. The control unit 26 can identify the load status of the AC output module 10 based on the output power. The control unit 26 can calculate the output power by detecting the current and voltage at the output terminal of the inverter unit 30. However, when the load connected to the AC output module 10 is a low-power load, the output current of the inverter unit 30 is very small, making it difficult to accurately detect the output power of the inverter unit 30. This can lead to a situation where the detected power is too low, resulting in a misjudgment that the load has been removed, causing the control unit 26 to control the inverter unit 30 to stop operating. In other words, when the AC input module is connected to a low-power load, the control unit 26 cannot identify whether the AC output module 10 is connected to a load based on the output power of the inverter unit 30, which may lead to a misjudgment of the load connection and control the inverter unit 30 to stop supplying power to the load.

[0052] To address this issue, the control unit 26 in the load access identification and detection circuit 20 provided in this embodiment can also be used to control the inverter unit 30 to stop working and perform a load access identification operation when the output power is lower than a preset threshold. Upon determining that the AC output module 10 is connected to a load, the control unit 26 restarts the inverter unit 30 to supply power to the load, thereby preventing the situation where the output power is too low and the load is mistakenly identified as removed, leading to a halt in power supply to the load. In this embodiment, although power supply to the load is initially stopped, the load access identification operation is restarted. The operation takes a short time, allowing the inverter unit 30 to be controlled promptly upon detecting a load, thus ensuring a stable power supply to the load.

[0053] The preset threshold is the power threshold used by control unit 26 to determine whether the system is in an unloaded state. When the output power of inverter unit 30 is lower than the preset threshold, control unit 26 will determine that there is no load connected and the system is in an unloaded state. The preset threshold can be set according to the actual performance of control unit 26, for example, it can be set to 15W, 10W, etc.

[0054] Therefore, when the output power of the inverter unit 30 is lower than the preset threshold, the inverter unit 30 is controlled to stop working and perform a load connection identification operation. The control unit 26 controls the first switch unit 22 to turn on and determines whether the AC output module 10 is connected to a load based on the sampled voltage value. When it is determined that the AC output interface is connected to a load, the inverter unit 30 is controlled to work again to supply power to the load. This prevents the control unit 26 from making a misjudgment of the load connection identification of the AC output module 10 based on the output power, and further improves the accuracy of the load connection identification of the AC output module 10.

[0055] It is understandable that when the control unit 26 determines that there is no load connected to the AC output module 10 based on the sampled voltage value, the inverter unit 30 does not need to supply power to the load. Therefore, the control unit 26 does not perform any other actions, keeping the inverter unit 30 in a stopped state.

[0056] Furthermore, in order to prevent the inverter unit 30 from operating under no-load conditions due to the control unit 26 failing to detect and identify the switch from a low-power load connection to a load removal state (i.e., from a light load to an unloaded state), the control unit 26 in this embodiment is also used to perform a load connection identification operation at a preset time interval when the output power is lower than a preset threshold and it is determined that the AC output module 10 is connected to a load, until the number of times the load connection identification operation is performed is greater than a preset number or the output power is greater than a preset threshold.

[0057] It is understandable that when a load connection identification operation determines that no load is connected to the AC output module 10, the control unit 26 controls the inverter unit 30 to stop working. This prevents the inverter unit 30 from operating under no-load conditions due to the inability to promptly identify low-power loads when they are unplugged. Additionally, when it is determined that no load is connected to the AC output module 10, the recorded number of load connection identification operations can be reset to zero.

[0058] The preset time interval and preset number of times can be set according to actual application needs. For example, the preset time interval can be set to 1 hour, half an hour, etc., and the preset number of times can be set to 12 times, 24 times, 30 times, etc.

[0059] In some embodiments, the control unit 26 can also be used to reset the number of load access identification operations to zero when the number of load access identification operations exceeds a preset number or the output power exceeds a preset threshold.

[0060] The fact that the number of load connection identification operations exceeds a preset number indicates that the AC output module 10 has been connected to a load for an extended period. Therefore, subsequent load connection identification operations are unnecessary, and the control unit 26 can directly maintain the inverter unit 30 operating to supply power to the load. When the output power of the inverter unit 30 exceeds a preset threshold, the control unit 26 can identify whether the AC output module 10 is connected to a load based on the output power, thus also eliminating the need for additional load connection identification operations. Therefore, in both cases, load identification operations can be discontinued, and the recorded number of operations can be reset to zero.

[0061] For example, such as Figure 4 As shown, Figure 4 This is a schematic diagram of the circuit structure of a load access identification and detection circuit 20 connected to an AC output module 10, as provided in an embodiment of this application.

[0062] In this example, the AC output module 10 includes L1 / L2 / N type AC output interfaces, which can be used to connect L1 / N type, L2 / N type, and L2 / L1 type loads.

[0063] Power supply unit 21 may include a flyback circuit, the input of which is used to connect to the positive and negative DC buses. Figure 4 The BUS+ and BUS- shown or the power supply (not shown) are used to receive DC power. The output of the flyback circuit is connected to the first terminal of the first switching unit 22, and the flyback circuit is used to convert DC power and provide the converted voltage to the first live wire terminal L1.

[0064] Specifically, the flyback circuit may include a transformer Tr, a flyback switch Q0, a diode D1, and a flyback capacitor C1. One end of the primary winding of the transformer Tr is connected to the positive DC bus BUS+ or the positive terminal of the power supply, and the other end of the primary winding is connected to the first terminal of the flyback switch Q0. The second terminal of the flyback switch Q0 is connected to the negative DC bus BUS-. One end of the secondary winding of the transformer Tr is connected to the anode of the diode D1. The cathode of the diode D1 is connected to one end of the flyback capacitor and the first switching unit 22. The other end of the flyback capacitor C1 is connected to the other end of the secondary winding. By controlling the on and off states of the flyback switch Q0, in conjunction with the transformer Tr, diode D1, and flyback capacitor C1, the DC current from the positive and negative DC buses (BUS+, BUS-) or the power supply is converted into voltage and supplied to the first live wire terminal L1.

[0065] The switching on and off of the flyback switch Q0 can be controlled by the control unit 26 or other controllers; this application does not impose any restrictions on this. The output voltage value after voltage conversion via the flyback circuit can be set according to actual needs, such as 3.3V, 5V, etc.

[0066] In some embodiments, when the load access identification and detection circuit 20 is installed in a device or apparatus having an AC output module 10, the flyback circuit can be inherently installed in the device or apparatus to provide the required voltage to other circuits, control chips, etc., in the device or apparatus, thereby eliminating the need to add additional components to the device or apparatus and further reducing costs. Of course, if the flyback circuit inherently installed in the device or apparatus cannot output the voltage required by the first live wire terminal L1 or the second live wire terminal L2, a winding that meets the requirements can be added to the original flyback circuit to enable the flyback circuit to output the required voltage to the first live wire terminal L1.

[0067] The first discharge unit 11 may include a first discharge resistor R1, which is connected between the first live wire terminal L1 and the neutral wire terminal N. The second discharge unit 12 may include a second discharge resistor R2, which is connected between the second live wire terminal L2 and the neutral wire terminal N. The first discharge resistor R1 and the second discharge resistor R2 can be set according to actual application requirements, for example, they can be 4*51kΩ, etc.

[0068] The first voltage divider unit 23 may include a first voltage divider resistor R3, which is connected between the first live wire terminal L1 and the second live wire terminal L2. The second voltage divider unit 24 may include a second voltage divider resistor R4, which is connected between the neutral wire terminal N and ground.

[0069] The first switching unit 22 may include a first controllable switch K1. The first end of the first controllable switch K1 is connected to the cathode of the diode D1 in the flyback circuit, and the second end of the first controllable switch K1 is connected to the first live wire terminal L1. The first controllable switch K1 is controlled to be turned on and off by the control unit 26. Of course, the second end of the first controllable switch K1 may also be connected to the second live wire terminal L2.

[0070] The sampling unit 25 may include a differential operational amplifier. The first and second input terminals of the differential operational amplifier are connected across the second voltage divider resistor R4, and the output terminal of the differential operational amplifier is connected to the control unit 26. The differential operational amplifier is used to acquire the voltage across the second voltage divider resistor R4 and amplify the acquired voltage as a sampled voltage value, which is then output to the control unit 26. Due to the amplification effect of the differential operational amplifier on the acquired voltage, the accuracy of voltage detection across the second voltage divider resistor R4 can be improved. The control unit 26 can also determine whether a load is connected based on the sampled voltage value. Therefore, the accuracy of the control unit 26 in determining whether the AC output module 10 is connected to a load can be improved.

[0071] The inverter unit 30 may include a first bridge arm, a second bridge arm, a third bridge arm, a fourth bridge arm, a first inductor Li1, and a second inductor Li2. The first bridge arm is connected between the positive and negative DC buses (BUS+, BUS-). The first bridge arm includes a first switch Q1 and a second switch Q2 connected in series. The first end of the first switch Q1 is connected to the positive DC bus BUS+. The second end of the first switch Q1 is connected to the first end of the second switch Q2 and is also connected to the first end of the first inductor Li1. The second end of the second switch Q2 is connected to the negative DC bus BUS-. The second end of the first inductor Li1 serves as the first output terminal of the inverter unit 30 and is connected to the first live wire terminal L1 via a second controllable switch K2.

[0072] The second bridge arm is also connected between the positive and negative DC buses. The second bridge arm includes a third switch Q3 and a fourth switch Q4 connected in series. The first end of the third switch Q3 is connected to the positive DC bus BUS+. The second end of the third switch Q3 is connected to the first end of the fourth switch Q4 and is connected to the first end of the second inductor Li2. The second end of the fourth switch Q4 is connected to the negative DC bus BUS-. The second end of the second inductor Li2 serves as the second output terminal of the inverter unit 30 and is connected to the second live wire terminal L2 through the third controllable switch K3.

[0073] Two bus capacitors are connected in series between the positive and negative DC buses (BUS+ and BUS-). These two bus capacitors are C2 (positive) and C3 (negative). C2 is connected to the positive DC bus BUS+, and C3 is connected to the negative DC bus BUS-. The third bridge arm is connected between the midpoint of the first bridge arm (the connection point of the first switch Q1 and the second switch Q2) and the midpoint of the two bus capacitors (the connection point of the positive and negative bus capacitors C2 and C3). The third bridge arm includes a fifth switch Q5 and a sixth switch Q6 connected in series, with the fifth and sixth switches arranged in opposite directions. The first end of the fifth switch Q5 is connected to the midpoint of the first bridge arm, and the second end of the fifth switch Q5 is connected to the second end of the sixth switch Q6 and serves as the third output terminal of the inverter unit, connected to the neutral terminal N via a fourth controllable switch K4. The first end of the sixth switch Q6 is connected to the midpoint of the two bus capacitors. The first and third bridge arms together form a single-phase T-shaped three-level circuit topology.

[0074] The fourth bridge arm connects the midpoint of the second bridge arm (i.e., the connection point of the third switch Q3 and the fourth switch Q4) and the midpoint of the two bus capacitors. The fourth bridge arm includes a seventh switch Q7 and an eighth switch Q8 connected in series, with the seventh and eighth switches arranged in opposite directions. The first end of the seventh switch Q7 is connected to the midpoint of the first bridge arm, and the second end of the seventh switch Q7 is connected to the second end of the eighth switch Q8, serving as the third output terminal of the inverter unit. This second end is connected to the neutral terminal N via a fourth controllable switch K4. The first end of the eighth switch Q8 is connected to the midpoint of the two bus capacitors. The second and fourth bridge arms together form a single-phase T-shaped three-level circuit topology, connected to the second live terminal L2 and the neutral terminal N via the third and fourth controllable switches K3 and K4, respectively. Additionally, the inverter unit 30 may include an output capacitor C4, which is connected between the second live terminal L2 and the neutral terminal N.

[0075] In some embodiments, a midpoint balancing circuit is further provided on the other side of the two bus capacitors relative to the inverter unit 30. The midpoint balancing circuit includes a fifth bridge arm and a third inductor Li3. The fifth bridge arm includes a ninth switch Q9 and a tenth switch Q10 connected in series. The first terminal of the ninth switch Q9 is connected to the positive DC bus BUS+, and the second terminal of the ninth switch Q9 is connected to the first terminal of the tenth switch Q10 and the first terminal of the third inductor Li3. The second terminal of the third inductor Li3 is connected to the midpoint of the two bus capacitors, and the second terminal of the tenth switch Q10 is connected to the negative DC bus BUS-. The midpoint balancing circuit is used to balance the voltage across the bus capacitors.

[0076] The control terminals of each switching transistor in the inverter unit 30 can be connected to the control unit 26. When the control unit 26 controls the inverter unit 30 to operate, it can output control signals to the control terminals of each switching transistor in the inverter unit 30 to control the switching on and off of each transistor, thereby converting DC power into AC power. Of course, the inverter unit 30 can also be equipped with a separate controller to control the switching on and off of each switching transistor. When the inverter unit 30 needs to operate, the control unit 26 can send a trigger signal to the controller. The controller outputs control signals according to the trigger signal to control each switching transistor of the inverter unit 30, thereby enabling the inverter unit 30 to operate.

[0077] The embodiments of this application do not limit the specific circuit structure of the inverter unit 30. For example, only two bridge arms may be set, or other inverter circuit topologies with multi-phase output may be set. Each phase of the inverter circuit topology may be connected to the first live wire terminal L1, the second live wire terminal L2 and the neutral wire terminal N through the second switching unit, etc.

[0078] The control unit 26 may include a DSP chip. The DSP chip is connected to the control terminal of the first controllable switch K1 to control the on / off state of the first controllable switch K1. The DSP chip is also connected to the output terminal of the sampling unit 25 to receive the sampled voltage value. Of course, the control unit 26 can be configured according to actual needs. It can be an integrated control chip or device, or it can be an independently configured chip or device that can perform calculation and control, such as a microcontroller unit (MCU), etc.

[0079] Figures 4 to 7 The equivalent circuit diagrams for AC output module 10 with no load connected, L1 / N type load connected, L2 / N type load connected, and L1 / L2 type load connected are shown below. Figures 4 to 7 This explains the working principle of the load access identification and detection circuit 20 provided in this application.

[0080] like Figure 4 As shown, when the AC output module 10 has no load connected and the control unit 26 performs a load connection identification operation, the control unit 26 controls the first controllable switch K1 to turn on, and the power supply unit 21 provides voltage to the first live wire terminal L1. At this time, the voltage across the second voltage divider resistor R4 is:

[0081]

[0082] Among them, V cc It is the voltage provided by the power supply unit 21 to the first live wire terminal L1.

[0083] Sampling unit 25 will V i0 After amplification, the sampled voltage value is output to the control unit 26.

[0084] like Figure 5 As shown, when the AC output module 10 is connected to an L1 / N type load, the L1 / N type load is connected between the first live wire terminal L1 and the neutral wire terminal N. At this time, if the control unit 26 performs a load connection identification operation, the control unit 26 controls the first controllable switch K1 to turn on, and the power supply unit 21 provides voltage to the first live wire terminal L1. The voltage across the second voltage divider resistor R4 is:

[0085]

[0086] At this time, sampling unit 25 will V i1 After amplification, the sampled voltage value is output to the control unit 26, where R L1 This is the equivalent resistance of an L1 / N type load.

[0087] like Figure 6 As shown, when the AC output module 10 is connected to an L2 / N type load, the L2 / N type load is connected between the second live wire terminal L2 and the neutral wire terminal N. At this time, if the control unit 26 performs a load connection identification operation, the control unit 26 controls the first controllable switch K1 to turn on, and the power supply unit 21 provides voltage to the first live wire terminal L1. The voltage across the second voltage divider resistor R4 is:

[0088]

[0089] At this time, sampling unit 25 will V i2 After amplification, the sampled voltage value is output to the control unit 26, where R L2 This is the equivalent resistance of an L2 / N type load.

[0090] like Figure 7 As shown, when the AC output module 10 is connected to an L1 / L2 type load, the L1 / L2 type load is connected between the first live wire terminal L1 and the second live wire terminal L2. At this time, if the control unit 26 performs a load connection identification operation, the control unit 26 controls the first controllable switch K1 to turn on, and the power supply unit 21 provides voltage to the first live wire terminal L1. The voltage across the second voltage divider resistor R4 is:

[0091]

[0092] At this time, sampling unit 25 will V i3 After amplification, the sampled voltage value is output to the control unit 26, where R L3 This is the equivalent resistance of the L1 / L2 type load.

[0093] Therefore, regardless of the type of load connected to the AC output module 10, the voltage across the second voltage divider resistor R4 will be different compared to when the AC output module 10 is not connected to a load, resulting in a different sampling voltage value output by the sampling unit 25. Thus, the control unit 26 can determine whether the AC output module 10 is connected to a load based on the sampling voltage value.

[0094] When the control unit 26 determines that there is a load connected to the AC output module 10, it controls the second controllable switch K2 to turn on and the inverter 31 in the inverter unit 30 to work, so that the AC power converted by the inverter unit 30 can be provided to the load.

[0095] Furthermore, when the AC output module 10 is connected to different types of loads, the voltage across the second voltage divider resistor R4 will also be different, meaning the sampling voltage value output by the sampling unit 25 will also be different. Therefore, the control unit 26 can also determine what type of load the AC output module 10 is connected to based on the specific sampling voltage value, and thus determine which terminal of the AC output module 10 the connected load is connected to, thereby controlling the corresponding second switching unit to turn on and provide the AC power converted by the inverter unit 30 to the connected load.

[0096] It is understood that this application also provides an energy storage device.

[0097] like Figure 8 As shown, Figure 8 This is a functional block diagram of an energy storage device 100 provided in an embodiment of this application. The energy storage device 100 includes an AC output module 10 and a load access identification and detection circuit 20 as described above.

[0098] By using the load access identification and detection circuit 20, the AC output module 10 in the energy storage device 100 can determine whether there is a load access regardless of the type of load connected. This eliminates the need to set up a corresponding load access detection circuit for each type of load access, simplifies the structure of the load access identification circuit, and reduces the cost of load identification of the AC output module 10 by the energy storage device 100.

[0099] In some embodiments, the energy storage device 100 may further include an energy storage battery (not shown in the figure). The energy storage battery can be connected to the input terminal of the power supply unit 21 of the identification and detection circuit 20 via a DC bus connection to the load, or it can be directly connected to the input terminal of the power supply unit 21.

[0100] Furthermore, the energy storage battery can also be connected to the input terminal of the inverter unit 30 via a DC bus to provide DC power to the inverter unit 30.

[0101] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A load access identification and detection circuit, characterized in that, This is applicable to AC output modules; the AC output module includes a first live wire terminal, a second live wire terminal, a neutral wire terminal, a first bleeder unit, and a second bleeder unit; the first live wire terminal, the second live wire terminal, and the neutral wire terminal are used for connection to a load; the first bleeder unit is connected between the first live wire terminal and the neutral wire terminal; the second bleeder unit is connected between the second live wire terminal and the neutral wire terminal; the load access identification and detection circuit includes a power supply unit, a first switching unit, a first voltage divider unit, a second voltage divider unit, a sampling unit, and a control unit; The output terminal of the power supply unit is connected to the first terminal of the first switch unit; the second terminal of the first switch unit is used to connect to one of the first live wire terminal and the second live wire terminal. The first voltage divider unit is connected between the first live wire terminal and the second live wire terminal; The second voltage divider unit is connected between the neutral terminal and ground; The sampling unit is connected to the second voltage divider unit and is used to collect the voltage on the second voltage divider unit and output the sampled voltage value; The control unit is connected to the output terminal of the sampling unit and to the control terminal of the first switching unit; the control unit is used to turn on the first switching unit when performing a load access identification operation, and to determine whether the AC output module is connected to a load based on the change in the sampled voltage value.

2. The load access identification and detection circuit as described in claim 1, characterized in that, The control unit is also configured to connect to an inverter unit, the input terminal of which is used to receive DC power, and the output terminal of which is connected to the first live wire terminal, the second live wire terminal, and the neutral wire terminal; the control unit is also configured to: When the AC output module is connected to the load, the inverter unit is controlled to convert the DC power to AC power to supply power to the load. When it is determined that the AC output module is not connected to the load, the inverter unit is controlled to stop working.

3. The load access identification and detection circuit as described in claim 2, characterized in that, It also includes multiple second switching units, wherein the first live wire terminal, the second live wire terminal and the neutral wire terminal are respectively connected to the output terminal of the inverter unit through at least one second switching unit; The control unit is also used for: When it is determined that the AC output module is connected to a load, the connection status between the load and the first live wire terminal, the second live wire terminal and the neutral wire terminal is determined according to the sampled voltage value; The second switching unit is turned on according to the connection status to provide the AC power converted by the inverter unit to the load.

4. The load access identification and detection circuit as described in claim 1, characterized in that, The control unit is also used for: After determining that the AC output module has a connected load based on the change in the sampled voltage value, the first switching unit is controlled to disconnect.

5. The load access identification and detection circuit as described in any one of claims 1 to 4, characterized in that, The power supply unit includes a flyback circuit. The input terminal of the flyback circuit is used to connect to a DC bus or a power supply to receive DC power. The output terminal of the flyback circuit is connected to the first terminal of the first switching unit. The flyback circuit is used to convert the DC power into voltage and provide the converted voltage to the first live wire terminal or the second live wire terminal.

6. The load access identification and detection circuit as described in claim 2, characterized in that, The control unit is also used for: Detect the output power of the inverter unit; When the output power is lower than a preset threshold, the inverter unit is controlled to stop working and the load connection identification operation is performed; when it is determined that the AC output module is connected to the load, the inverter unit is controlled to work again to supply power to the load.

7. The load access identification and detection circuit as described in claim 6, characterized in that, The control unit is also used for: When the output power is lower than a preset threshold and it is determined that the AC output module is connected to the load, the load connection identification operation is performed at preset time intervals until the number of times the load connection identification operation is performed is greater than a preset number or the output power is greater than the preset threshold.

8. The load access identification and detection circuit as described in claim 7, characterized in that, The control unit is also used for: When the number of load access identification operations exceeds a preset number or the output power exceeds the preset threshold, the number of load access identification operations is reset to zero.

9. The load access identification and detection circuit according to claim 1, characterized in that, The first discharge unit, the second discharge unit, the first voltage divider unit, and the second voltage divider unit have different impedances.

10. An energy storage device, characterized in that, It includes an AC output module and a load access identification and detection circuit as described in any one of claims 1 to 9.

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