Power supply system

Abstract

The utility model discloses a power supply system which comprises M energy storage devices and N grid-connected and off-grid switching devices. M is an integer greater than or equal to 2, and N is an integer greater than or equal to 1; each energy storage device comprises an energy storage converter, the direct current side of the energy storage converter is used for connecting the corresponding battery pack, and the alternating current side of the energy storage converter is connected with the alternating current bus; the first ends of the N pieces of grid-connected and off-grid switching equipment are connected with the alternating current bus, and the second ends of the N pieces of grid-connected and off-grid switching equipment are used for being connected with a power grid; the signal ends of the N pieces of grid-connected and off-grid switching equipment and the signal ends of the M pieces of energy storage equipment are connected with the synchronous bus; the AC bus is used for supplying power to load equipment. Through the power supply system, the power supply guarantee of the important load when the power supply of the power grid is unstable or the power grid fails is realized. Through the parallel configuration of the plurality of energy storage devices, not only can important load requirements of different power levels be met, but also the flexibility and expansibility of the system can be improved, and the device design time cost caused by the difference of different load power requirements can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of power supplies, in particular to a power supply system. Background Art

[0002] In areas with relatively underdeveloped power system infrastructure, power grid instability, insufficient load-carrying capacity, and frequent power outages are common. To ensure the power supply of critical loads, energy storage devices are often used in conjunction with the grid to provide uninterrupted power to these loads.

[0003] However, in different application scenarios, the power requirements of important loads may vary greatly, and it is necessary to develop energy storage devices with different powers for important loads of different power levels. Therefore, when there are many types of important loads, the time cost of designing energy storage devices will be very high. Utility Model Content

[0004] In view of this, the present invention provides a power supply system.

[0005] In a first aspect, the present invention provides a power supply system comprising M energy storage devices and N grid-connected and off-grid switching devices; M is an integer greater than or equal to 2, and N is an integer greater than or equal to 1; each of the energy storage devices comprises an energy storage converter, wherein the DC side of the energy storage converter is used to connect to a corresponding battery pack, and the AC side of the energy storage converter is connected to an AC bus;

[0006] The first ends of the N on-grid and off-grid switching devices are connected to the AC bus, and the second ends of the N on-grid and off-grid switching devices are used to connect to the power grid;

[0007] The signal terminals of the N on-grid and off-grid switching devices and the signal terminals of the M energy storage devices are connected to a synchronous bus;

[0008] The AC bus is used to supply power to load equipment.

[0009] In a possible implementation, the output powers of the M energy storage devices are the same.

[0010] In a possible implementation, the number of the energy storage devices is the same as the number of the on-grid and off-grid switching devices.

[0011] In a possible implementation, the on-grid and off-grid switching device includes a fast switching device, a first end of the fast switching device is connected to the power grid, and a second end of the fast switching device is connected to the AC bus.

[0012] In a possible implementation, the synchronization bus includes a communication synchronization bus;

[0013] The signal ends of the N on-grid and off-grid switching devices and the signal ends of the M energy storage devices are connected to the communication synchronization bus.

[0014] In a possible implementation, the synchronization bus further includes a status synchronization bus;

[0015] The signal ends of the N on-grid and off-grid switching devices and the signal ends of the M energy storage devices are also connected to the state synchronization bus.

[0016] In a possible implementation, the signal terminal of the on-grid and off-grid switching device includes a first signal terminal and a second signal terminal;

[0017] The first signal terminal of the on-grid and off-grid switching device is connected to the communication synchronization bus, and the second signal terminal of the on-grid and off-grid switching device is connected to the status synchronization bus.

[0018] In a possible implementation, the on-grid and off-grid switching device further includes a state switch; two ends of the state switch are respectively connected to the positive and negative poles of the state synchronization bus.

[0019] In a possible implementation, the second signal terminal of the on-grid and off-grid switching device is a digital signal interface.

[0020] In a possible implementation, the signal terminal of the energy storage device includes a first signal terminal and a second signal terminal;

[0021] The first signal terminal of the energy storage device is connected to the communication synchronization bus, and the second signal terminal of the energy storage device is connected to the state synchronization bus.

[0022] In a possible implementation, the second signal terminal of the energy storage device is a digital signal interface.

[0023] The utility model provides a power supply system, which includes multiple energy storage devices and at least one on-grid and off-grid switching device. Multiple energy storage devices are connected in parallel to supply power to load devices. The number of energy storage devices can be flexibly configured according to the actual power requirements of the load devices, so as to achieve power supply support for load devices of different power levels, avoiding the high cost of designing dedicated energy storage devices for a single power level in traditional methods. This enables the system to better adapt to the power change requirements in various application scenarios, thereby improving the flexibility and adaptability of the system. In addition, the connection relationship between the power grid and the load device is controlled by the on-grid and off-grid switching device in the system. When the power supply of the power grid is unstable or interrupted, the power supply source of the load device can be switched to ensure uninterrupted power supply to the load device, and also avoid the negative impact of power grid abnormalities on the power supply of the load device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1A schematic diagram of a power supply system provided by the utility model;

[0025] Figure 2 A schematic diagram of another power supply system provided by the present invention;

[0026] Figure 3 A schematic diagram of another power supply system provided by the present utility model;

[0027] Figure 4 A schematic diagram of another power supply system provided by the present invention;

[0028] Figure 5 A schematic diagram of a power supply system provided by the utility model;

[0029] Figure 6 A schematic diagram of another power supply system provided by the present invention;

[0030] Figure 7 A connection topology diagram of a state synchronization bus provided by the utility model;

[0031] Figure 8 This is a schematic diagram of an on-grid and off-grid switching process provided by the utility model. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0033] In view of the technical problems existing in the related technologies, this utility model provides a power supply system. Figure 1 and Figure 2 .

[0034] The power supply system includes M energy storage devices and N on-grid and off-grid switching devices; M is an integer greater than or equal to 2, and N is an integer greater than or equal to 1. Figure 1 The power supply system shown includes multiple energy storage devices and multiple on-grid and off-grid switching devices. Figure 2 The power supply system shown includes an on-grid and off-grid switching device and multiple energy storage devices.

[0035] The M energy storage devices are used to supply power to the load devices through the AC bus together with the grid in the grid-connected state; and are used to supply power to the load devices through the AC bus in the off-grid state.

[0036] The energy storage device includes an energy storage inverter. The DC side of the energy storage inverter is connected to the corresponding battery pack of the energy storage device, and the AC side of the energy storage inverter is connected to the AC bus. The battery pack can be built into the energy storage device or externally connected. The energy storage inverter converts the DC power provided by the battery pack into AC power, which is then used to power the load device via the AC bus.

[0037] In an embodiment of the present invention, the number of energy storage devices in the power supply system can be determined based on the power requirements of the load devices. Specifically, the value of M is determined based on the power requirements of the load devices. The sum of the output power of the M energy storage devices is at least equal to the rated power of the load devices. Multiple energy storage devices are connected in parallel via the AC bus to power the load devices, allowing the energy storage devices to meet the load devices' power requirements in an off-grid state.

[0038] The on-grid and off-grid switching device is used to control the on and off of the power grid and the AC bus. The first end of the on-grid and off-grid switching device is connected to the AC bus, and the second end of the on-grid and off-grid switching device is used to connect to the power grid. In the on-grid state, the N on-grid and off-grid switching devices all control the conduction between the power grid and the AC bus, and the power grid and M energy storage devices jointly power the load devices through the AC bus; or the power grid charges the battery packs corresponding to the M energy storage devices through the AC bus and powers the load devices. In the off-grid state, the on-grid and off-grid switching devices all control the disconnection between the power grid and the AC bus, and the M energy storage devices power the load devices through the AC bus.

[0039] The signal terminals of each on-grid and off-grid switching device and the signal terminals of each energy storage device are connected to a synchronization bus. The synchronization bus is used to synchronize the states of each on-grid and off-grid switching device and each energy storage device, allowing each energy storage device and each on-grid and off-grid switching device to operate in either a grid-connected state or an off-grid state.

[0040] In one possible implementation, the on-grid and off-grid switching device is also used to detect the operating status of the power grid. As an example, when a certain on-grid and off-grid switching device detects a power grid anomaly, it can switch from a on-grid state to an off-grid state, and synchronize the information to each energy storage device and other on-grid and off-grid switching devices via a synchronization bus, so that each energy storage device and other on-grid and off-grid switching devices switch from a on-grid state to an off-grid state. As another example, when a certain on-grid and off-grid switching device detects that the power grid has returned to normal, it can switch from an off-grid state to a on-grid state, and synchronize the information to each energy storage device and other on-grid and off-grid switching devices via a synchronization bus, so that each energy storage device and other on-grid and off-grid switching devices switch from an off-grid state to a on-grid state.

[0041] The power supply system provided by this utility model utilizes multiple energy storage devices connected in parallel to an AC busbar, which then supplies power to load devices, thereby meeting the power requirements of the load devices. In different application scenarios, the number of energy storage devices can be adjusted to meet the power requirements of different load devices, eliminating the need to develop corresponding energy storage devices for load devices of different power, thus saving energy storage device development costs.

[0042] In a possible implementation, the load device is, for example, a server, a computer, a lighting device, a medical device, a power device, an industrial production device, and the like.

[0043] In one possible implementation, the M energy storage devices can have the same output power. That is, the power supply system can utilize M energy storage devices of the same specifications. When using this power supply system to power load devices with varying power requirements, the number of energy storage devices can be adjusted based on the power requirements of the load devices. Furthermore, using energy storage devices of the same specifications simplifies management and maintenance of the energy storage devices, thereby enhancing their uniformity.

[0044] by Figure 1 and Figure 2 As shown, in Figure 2 In the power supply system shown, multiple energy storage devices correspond to one on-grid and off-grid switching device, and the grid current is integrated or blocked through the on-grid and off-grid switching device. In order to reduce the load pressure of the on-grid and off-grid switching device, the following can also be used: Figure 1 The power supply system shown in the figure. Multiple on-grid and off-grid switching devices are connected in parallel. The grid current can be fed into the AC busbar through these devices, achieving voltage division. As an implementation, the number of energy storage devices is the same as the number of on-grid and off-grid switching devices. There is a one-to-one correspondence between the energy storage devices and the on-grid and off-grid switching devices.

[0045] In the above embodiments, the on-grid and off-grid switching device is used to control the connection between the power grid and the AC busbar, thereby achieving on-grid and off-grid switching. In one possible implementation, the on-grid and off-grid switching device can achieve on-grid and off-grid switching via an internal fast switching device. Specifically, the on-grid and off-grid switching device includes a fast switching device, a first end of which is connected to the power grid, and a second end of which is connected to the AC busbar.

[0046] Fast switching devices have a certain operating delay, meaning they require a certain amount of time to switch from a closed state to an open state, or vice versa. During on-grid and off-grid switching, instantaneous switching can cause sudden current fluctuations, potentially damaging equipment. The present invention utilizes fast switching devices with a certain operating delay to reduce the current surges associated with on-grid and off-grid switching, thereby protecting equipment.

[0047] As an example, the fast switching device can be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), a Bipolar Junction Transistor (BJT), an Insulated-Gate Bipolar Transistor (IGBT), an optocoupler fast relay, etc.

[0048] In the above embodiment, each energy storage device and each on-grid and off-grid switching device can synchronize their states via a synchronization bus. Specifically, the present invention provides two implementation methods, which are described below in conjunction with the accompanying drawings.

[0049] In one possible implementation, the synchronization bus includes a communication synchronization bus. Figure 3 and Figure 4 As shown, Figure 3 For Figure 1 A topological diagram is further provided based on Figure 4 For Figure 2 A topological diagram is further provided based on the above.

[0050] The signal terminals of each on-grid and off-grid switching device and each energy storage device are connected to a communication synchronization bus. This communication synchronization bus enables state synchronization between each on-grid and off-grid switching device and each energy storage device. The communication synchronization bus is used not only for state synchronization but also for data transmission. For example, the on-grid and off-grid switching device can transmit grid information to each energy storage device via the communication synchronization bus, enabling each energy storage device to synchronize with the grid based on this grid information.

[0051] In another possible implementation, the synchronization bus includes a communication synchronization bus and a status synchronization bus. Figure 5 and Figure 6 As shown, Figure 5 For Figure 1 A topological diagram is further provided based on Figure 6 For Figure 2 A topological diagram is further provided based on the above.

[0052] The signal terminals of each on-grid and off-grid switching device and the signal terminals of each energy storage device are also connected to a state synchronization bus. The state synchronization bus includes two states: open circuit and short circuit. Furthermore, the state synchronization bus is only used for action indication; data is still transmitted via the communication synchronization bus. Compared to the communication synchronization bus, using the state synchronization bus for on-grid and off-grid state synchronization can shorten on-grid and off-grid switching delays, reduce power-off time of load devices, and ensure reliable power supply for load devices. The specific implementation process of action indication via the state synchronization bus is described in detail in the following embodiments.

[0053] Specifically, the signal end of the energy storage device includes a first signal end and a second signal end; the first signal end of the energy storage device is connected to the communication synchronization bus, and the second signal end of the energy storage device is connected to the status synchronization bus.

[0054] The first signal terminal of the energy storage device can be used for transmitting and receiving data, and the second signal terminal of the energy storage device can be used for determining the state of the state synchronization bus. In one implementation, the second signal terminal of the energy storage device is a digital imaging (DI) interface.

[0055] Specifically, the signal end of the on-grid and off-grid switching device includes a first signal end and a second signal end; wherein the first signal end of the on-grid and off-grid switching device is connected to the communication synchronization bus, and the second signal end of the on-grid and off-grid switching device is connected to the status synchronization bus.

[0056] The first signal terminal of the on-grid switching device can be used for transmitting and receiving data, and the second signal terminal of the on-grid switching device can be used for determining the state of the state synchronization bus. In one implementation, the second signal terminal of the on-grid switching device is a digital signal interface.

[0057] In a possible implementation, the on-grid and off-grid switching device further includes a state switch; both ends of the state switch are allocated with positive and negative poles connected to the state synchronization bus, specifically as follows Figure 7 As shown, Figure 7 This is a connection topology diagram of a state synchronization bus provided by the present invention. S1, S2, S3 and SN are all state switches.

[0058] The state switch can be an internal switch in the on-grid or off-grid switching device, or it can be an external switch. The second signal terminal of each on-grid or off-grid switching device is connected to the state synchronization bus through a state switch, meaning there is a one-to-one correspondence between the state switch and the on-grid or off-grid switching device. When any one of the N state switches is closed, the state synchronization bus is short-circuited; when all N state switches are open, the state synchronization bus is open. The switching action of the state switch is instantaneous.

[0059] The power supply systems provided by the above embodiments can all supply power to load devices through multiple energy storage systems in parallel, thereby saving the development cost of energy storage devices. In addition, at least one on-grid and off-grid switching device can realize on-grid and off-grid switching of the power supply system according to the state of the power grid. Figure 3-Figure 6 The power supply system provided introduces the on-grid and off-grid switching process of the power supply system.

[0060] The on-grid and off-grid switching device uses a fast-acting switching device to switch between the grid and the AC busbar. In the event of a grid anomaly, the on-grid and off-grid switching device can open the fast-acting switching device, severing the connection between the grid and the AC busbar. In the event of a grid anomaly, the on-grid and off-grid switching device can close the fast-acting switching device, restoring the connection between the grid and the AC busbar.

[0061] During the transition from grid-connected to off-grid mode, the energy storage device must enter a first transition state and then an off-grid state. In the first transition state, the energy storage device's converter disconnects the current loop from the control loop, setting the grid-connected current to zero from a preset value. It also latches the grid phase and capacitor voltage commands, saving the integrated output of the grid-connected current loop.

[0062] During the transition from off-grid to grid-connected, the energy storage device must enter a second transition state and then a grid-connected state. In the second transition state, the energy storage converter rejoins the current loop to the control loop and gradually increases the grid-connected current from 0 to a preset value.

[0063] In the first possible implementation, Figure 3 Taking the power supply system shown in the figure as an example, the off-grid switching process is as follows:

[0064] During grid operation, the fast-switch devices in each on-grid and off-grid switching device are all in the closed state, and each energy storage device operates in a grid-connected state. If a particular on-grid and off-grid switching device (using on-grid and off-grid switching device 1 as an example) determines that the grid is abnormal, on-grid and off-grid switching device 1 controls the fast-switch device 1 in the on-grid and off-grid switching device 1 to switch from the closed state to the open state, and sends a first switching instruction to each of the other on-grid and off-grid switching devices via the communication synchronization bus. The first switching instruction is used to instruct the on-grid and off-grid switching device to disconnect the grid from the load device.

[0065] After receiving the first switching instruction, each other on-grid and off-grid switching device controls the fast switching device inside it to change from a closed state to an open state. After determining that the fast switching device inside it is in the open state, each other on-grid and off-grid switching device feeds back the first completion instruction to the on-grid and off-grid switching device 1 through the communication bus.

[0066] After receiving the first completion instruction, the on-grid and off-grid switching device 1 sends a second switching instruction to each energy storage device through the communication bus. The second switching instruction is used to instruct the energy storage device to switch from the grid-connected state to the first transition state.

[0067] After receiving the second switching instruction, each energy storage device switches from the grid-connected state to the first transition state, and feeds back a second completion instruction to the grid-connected and off-grid switching device 1 via the communication bus.

[0068] When the on-grid and off-grid switching device 1 receives the second completion instruction fed back by each energy storage device and determines that the fast switching device 1 is in the disconnected state, it sends a third switching instruction to each energy storage device through the communication bus; the third switching instruction is used to instruct the energy storage device to switch from the first transition state to the off-grid state.

[0069] Each energy storage device receives the third switching instruction and switches from the first transition state to the off-grid state, thereby realizing the switch of the power supply system from the grid-connected state to the off-grid state.

[0070] When the on-grid and off-grid switching device 1 determines that the power grid has returned to normal, it sends the power grid information to each energy storage device through the communication bus.

[0071] After receiving the grid information, each energy storage device adjusts the frequency, phase and amplitude according to the grid information, achieves synchronization with the grid, and feeds back the synchronization completion information to the on-grid and off-grid switching device 1 through the communication bus.

[0072] After receiving the synchronization completion information fed back by each energy storage device, the on-grid and off-grid switching device 1 controls the fast switching device 1 to change from the open state to the closed state, and sends a fourth switching instruction to other on-grid and off-grid switching devices through the communication bus; the fourth switching instruction is used to instruct the on-grid and off-grid switching device to restore the connection between the power grid and the load device.

[0073] After receiving the fourth switching instruction, each other on-grid and off-grid switching device controls the internal fast switching device to change from the open state to the closed state. After the internal fast switching device is in the closed state, each other on-grid and off-grid switching device feeds back the third completion instruction to the on-grid and off-grid switching device 1 through the communication bus.

[0074] After receiving the third completion instruction fed back by the other on-grid and off-grid switching devices, the on-grid and off-grid switching device 1 sends a fifth switching instruction to each energy storage device through the communication bus; the fifth switching instruction is used to instruct the energy storage device to switch from the off-grid state to the second transition state, and the second transition state is the intermediate state of the energy storage device from the off-grid state to the grid-connected state.

[0075] After receiving the fifth switching instruction, each energy storage device switches from the off-grid state to the second transition state, and feeds back the fourth completion instruction to the on-grid and off-grid switching device 1 via the communication bus.

[0076] When the on-grid and off-grid switching device 1 receives the fourth completion instruction fed back by each energy storage device and determines that the fast switching device 1 is in the disconnected state, it sends a sixth switching instruction to each energy storage device through the communication bus; the sixth switching instruction is used to instruct the energy storage device to switch from the second transition state to the grid-connected state.

[0077] Each energy storage device switches from the second transition state to the grid-connected state according to the sixth switching instruction.

[0078] In the second possible implementation, Figure 4 Taking the power supply system shown in the figure as an example, the off-grid switching process is as follows:

[0079] During grid operation, the fast-acting switching devices in each on-grid / off-grid switching device are closed, and each energy storage device operates in a grid-connected state. If on-grid / off-grid switching device 1 determines that the grid is abnormal, it controls fast-acting switching device 1 from closed to open and sends a second switching instruction to each energy storage device via the communication bus.

[0080] After receiving the second switching instruction, each energy storage device switches from the grid-connected state to the first transition state, and feeds back a second completion instruction to the grid-connected and off-grid switching device 1 via the communication bus.

[0081] After receiving the second completion instruction fed back by each energy storage device, the on-grid and off-grid switching device 1 controls the fast switching device 1 to change from a closed state to an open state; and when it is determined that the fast switching device 1 is in the open state, it sends a third switching instruction to each energy storage device through the communication bus.

[0082] After receiving the second switching instruction, each energy storage device switches from the first transition state to the off-grid state.

[0083] When it is determined that the power grid has returned to normal, the grid-connected and off-grid switching device 1 sends the grid information to each energy storage device through the communication bus.

[0084] After receiving the grid information, each energy storage device achieves synchronization with the grid according to the grid information, and feeds back synchronization completion information to the on-grid and off-grid switching device 1 through the communication bus.

[0085] After receiving the synchronization completion information fed back by each energy storage device, the on-grid and off-grid switching device 1 controls the fast switching device 1 to change from an open state to a closed state, and sends a fifth switching instruction to each energy storage device through the communication bus.

[0086] After receiving the fifth switching instruction, each energy storage device switches from the off-grid state to the second transition state, and feeds back the fourth completion instruction to the on-grid and off-grid switching device 1 via the communication bus.

[0087] After receiving the fourth completion instruction fed back by each energy storage device and determining that the fast switch device 1 is in the disconnected state, the on-grid and off-grid switching device 1 sends a sixth switching instruction to each energy storage device through the communication bus.

[0088] After receiving the sixth switching instruction, each energy storage device switches from the second transition state to the grid-connected state.

[0089] In a third possible implementation, Figure 5 As an example, the power supply system shown in the figure is switched off-grid. Figure 8 As shown, N on-grid and off-grid switching devices include an on-grid and off-grid switching device 1 and an on-grid and off-grid switching device 2 as an example.

[0090] When a grid anomaly occurs, the on-grid and off-grid switching device can quickly identify the anomaly. It is assumed that on-grid and off-grid switching device 1 first identifies the grid anomaly. Once this is determined, on-grid and off-grid switching device 1 controls fast switching device 1 within on-grid and off-grid switching device 1 from a closed state to an open state. Simultaneously, it controls state switch 1 within on-grid and off-grid switching device 1 from an open state to a closed state. Because state switch 1 is closed, the state synchronization bus short-circuits. Simultaneously, on-grid and off-grid switching device 2 and the energy storage devices detect the state synchronization bus short-circuit.

[0091] After determining that the state synchronization bus is short-circuited, each energy storage device switches from the grid-connected state to the first transition state.

[0092] After determining that the state synchronization bus is short-circuited, the on-grid switching device 2 controls the fast switching device 2 in the on-grid switching device 2 to change from a closed state to an open state, and controls the state switch 2 in the on-grid switching device 2 to change from an open state to a closed state.

[0093] When on-grid switching device 1 detects that fast switching device 1 is in the off state, it controls state switch 1 from closed to open. When on-grid switching device 2 detects that fast switching device 2 is in the off state, it controls state switch 2 from closed to open. Since both state switches 1 and 2 are in the off state, the state synchronization bus is open. Simultaneously, each energy storage device can detect that the state synchronization bus is open.

[0094] When the state synchronization bus is determined to be open, each energy storage device switches from the first transition state to the off-grid state, thereby realizing the switch from the grid-connected state to the off-grid state.

[0095] When a grid anomaly occurs, the on-grid and off-grid switching device can quickly identify the anomaly. It is designed that the on-grid and off-grid switching device 2 first determines that the grid has returned to normal. Once this is determined, the on-grid and off-grid switching device 2 transmits the grid information to each energy storage device via the communication bus.

[0096] After receiving the grid information, each energy storage device achieves synchronization with the grid according to the grid information, and feeds back synchronization completion information to the on-grid and off-grid switching device 2 via the communication bus.

[0097] After receiving synchronization completion information from each energy storage device, the on-grid and off-grid switching device 2 controls the fast switching device 2 from the open state to the closed state, and controls the state switch 2 from the open state to the closed state. Since the state switch 2 is in the closed state, the state synchronization bus is short-circuited.

[0098] When it is determined that the state synchronization bus is short-circuited, each energy storage device switches from the off-grid state to the second transition state.

[0099] When determining that the state synchronization bus is short-circuited, the on-grid and off-grid switching device 1 controls the fast switching device 1 to change from an open state to a closed state, and controls the state switch 1 to change from an open state to a closed state.

[0100] When the on-grid switching device 2 detects that the fast switching device 2 is in the closed state, it controls the state switch 2 to be opened. The on-grid switching device 1 is also configured to control the state switch 1 to be opened when the fast switching device 1 is in the closed state. Both state switches 1 and 2 are in the open state, and the state synchronization bus is open.

[0101] Each energy storage device is used to convert from the second transition state to the grid-connected state when it is determined that the state synchronization bus is open, thereby realizing the conversion from the off-grid state to the grid-connected state.

[0102] In the above process, state synchronization is achieved based on a low-latency state synchronization bus, which can improve the response speed of the power supply system to grid state changes, improve the stability of the power supply system, and achieve rapid switching of the power supply source for the load equipment.

[0103] In a fourth possible implementation, Figure 6 Taking the power supply system shown in the figure as an example, the on-grid and off-grid switching process is as follows:

[0104] When a grid abnormality is detected, the on-grid switching device 1 controls the fast switching device 1 within the on-grid switching device 1 to change from a closed state to an open state, and controls the state switch 1 within the on-grid switching device 1 to change from an open state to a closed state. The state switch 1 is in the closed state, and the state synchronization bus is short-circuited.

[0105] When each energy storage device determines that the state synchronization bus is short-circuited, it transitions from the grid-connected state to the first transition state. When the on-grid / off-grid switching device 1 determines that the fast switch device 1 is in the off state, it controls the state switch 1 from the closed state to the open state. When the state switch 1 is in the off state, the state synchronization bus is open. When each energy storage device determines that the state synchronization bus is open, it transitions from the first transition state to the off-grid state.

[0106] When the grid is determined to be back to normal, the on-grid switching device 1 sends grid information to each energy storage device via the communication bus. After receiving the grid information, each energy storage device synchronizes with the grid based on the grid information and sends synchronization completion information back to the on-grid switching device 1 via the communication bus.

[0107] After receiving synchronization completion information from each energy storage device, the on-grid and off-grid switching device 1 controls the fast switching device 1 from the open state to the closed state, and controls the state switch 1 from the open state to the closed state. The state switch 1 is in the closed state, and the state synchronization bus is short-circuited.

[0108] When each energy storage device determines that the state synchronization bus is short-circuited, it transitions from the off-grid state to the second transition state. When the on-grid switching device 1 detects that the fast switching device 1 is closed, it controls the state switch 1 from the closed state to the open state. When the state switch 1 is open, the state synchronization bus is open.

[0109] When the state synchronization bus is determined to be open, each energy storage device switches from the second transition state to the grid-connected state, thereby realizing the transition from the off-grid state to the grid-connected state.

[0110] In the above embodiment, the power supply system can realize on-grid and off-grid switching through the communication synchronization bus, and can also realize on-grid and off-grid switching more efficiently through the communication synchronization bus and the status synchronization bus.

[0111] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0112] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power supply system, characterized in that: The system comprises M energy storage devices and N grid-connected and off-grid switching devices; M is an integer greater than or equal to 2, and N is an integer greater than or equal to 1; each energy storage device comprises an energy storage converter, the DC side of the energy storage converter is used to connect to a corresponding battery pack, and the AC side of the energy storage converter is connected to an AC bus; The first ends of the N on-grid and off-grid switching devices are connected to the AC bus, and the second ends of the N on-grid and off-grid switching devices are used to connect to the power grid; The signal terminals of the N on-grid and off-grid switching devices and the signal terminals of the M energy storage devices are connected to a synchronous bus; The AC bus is used to supply power to load equipment.

2. The system according to claim 1, wherein: The output powers of the M energy storage devices are the same.

3. The system according to claim 1, wherein: The number of the energy storage devices is the same as the number of the on-grid and off-grid switching devices.

4. The system according to claim 1, wherein: The on-grid and off-grid switching device includes a fast switching device, a first end of the fast switching device is connected to the power grid, and a second end of the fast switching device is connected to the AC bus.

5. The system according to claim 1, wherein: The synchronization bus includes a communication synchronization bus; The signal ends of the N on-grid and off-grid switching devices and the signal ends of the M energy storage devices are connected to the communication synchronization bus.

6. The system according to claim 5, characterized in that The synchronization bus also includes a state synchronization bus; The signal ends of the N on-grid and off-grid switching devices and the signal ends of the M energy storage devices are also connected to the state synchronization bus.

7. The system according to claim 6, characterized in that The signal terminal of the on-grid and off-grid switching device includes a first signal terminal and a second signal terminal; The first signal terminal of the on-grid and off-grid switching device is connected to the communication synchronization bus, and the second signal terminal of the on-grid and off-grid switching device is connected to the status synchronization bus.

8. The system according to claim 7, characterized in that The on-grid and off-grid switching device further comprises a state switch; both ends of the state switch are respectively connected to the positive and negative poles of the state synchronization bus.

9. The system according to claim 7, wherein: The second signal terminal of the on-grid and off-grid switching device is a digital signal interface.

10. The system according to claim 6, wherein: The signal terminal of the energy storage device includes a first signal terminal and a second signal terminal; The first signal terminal of the energy storage device is connected to the communication synchronization bus, and the second signal terminal of the energy storage device is connected to the state synchronization bus.

11. The system according to claim 10, wherein: The second signal terminal of the energy storage device is a digital signal interface.

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