Power supply system

Abstract

The invention discloses a power supply system which comprises a first bus, a second bus, a standby power supply unit and a control unit. The first bus is configured to be connected to a mains supply through the first switch unit, the second bus is configured to be electrically connected with a load through the second switch unit, and the first bus and the second bus are connected in series through the third switch unit; the standby power supply unit is electrically connected with the first bus through the fourth switch unit, and is electrically connected with the second bus through the fifth switch unit; when the mains supply is abnormal, the first switch unit is controlled to disconnect the mains supply, and the standby power supply unit is controlled to output electric energy to the second bus; when the standby power supply unit is abnormal, the fourth switch unit and the fifth switch unit are controlled to be disconnected, the standby power supply unit is disconnected with the first bus and the second bus, the third switch unit is controlled to be closed, and the electric energy output by the first bus is directly output to the second bus.

Description

Technical Field

[0001] The embodiments of the present invention relate to power grid technology, and in particular to a power supply system. Background Art

[0002] With the rapid development and widespread application of information technology, uninterruptible power supplies (UPSs) have become an essential component in many industries. An uninterruptible power system (UPS) is a device that provides stable power to critical equipment. It is widely used in various fields to ensure that equipment can continue to operate normally during power outages or fluctuations, avoiding data loss, equipment damage, or service interruptions. UPSs are primarily used in data centers, communications equipment, medical devices, industrial automation, transportation facilities, large-scale events, and financial trading systems.

[0003] Common UPS power supplies on the market have the following problems: they do not meet the high voltage and high power level requirements; they do not have a millisecond-level fast conversion time when the mains power fails; and when the backup power supply fails or is under maintenance, they cannot guarantee continuous power supply to the load. Summary of the Invention

[0004] The present invention provides a power supply system to achieve the purpose of solving at least one defect in the prior art.

[0005] An embodiment of the present invention provides a power supply system, comprising: a first busbar, a second busbar, a backup power supply unit, and a control unit;

[0006] The first busbar is configured to be connected to the mains through a first switch unit, the second busbar is configured to be electrically connected to the load through a second switch unit, and the first busbar and the second busbar are further connected in series through a third switch unit;

[0007] The backup power supply unit is electrically connected to the first busbar through the fourth switch unit, and the backup power supply unit is electrically connected to the second busbar through the fifth switch unit;

[0008] The control unit is configured as follows:

[0009] When the mains power is normal, the electric energy of the first bus is controlled to pass through the backup power supply unit and then be output to the second bus, and then be output to the load by the second bus;

[0010] When the mains power is abnormal, the first switch unit is controlled to disconnect the mains power, and the backup power supply unit is controlled to output electric energy to the second bus, and the second bus is used to output electric energy to the load;

[0011] When the backup power supply unit is abnormal, the fourth switch unit and the fifth switch unit are controlled to be disconnected, the backup power supply unit is disconnected from the first bus and the second bus, the third switch unit is controlled to be closed, and the electric energy output by the first bus is directly output to the second bus, and then output to the load by the second bus.

[0012] Optionally, the backup power supply unit includes a power generation unit and an energy storage unit;

[0013] The power generation unit is coupled to the first bus unit, and the energy storage unit is coupled to the first bus and the second bus;

[0014] The power generation unit is used to supply power to the load when the mains power is abnormal;

[0015] The energy storage unit is used to store part of the electric energy output to the load when the mains power or the power generation unit supplies power to the load, and to temporarily supply power to the load when the power generation unit and the mains power are switched.

[0016] Optionally, the control unit is configured as:

[0017] When the mains power is abnormal, disconnecting the mains power by controlling the first switch unit;

[0018] Controlling the energy storage unit to be in an island mode, and in the island mode, controlling the energy storage unit to output electric energy to the second bus, and outputting electric energy from the second bus to the load;

[0019] Controlling the power generation unit to start, controlling the power generation unit to perform synchronous phase locking with the output voltage of the energy storage unit, and after the synchronous phase locking is completed, controlling the energy storage unit to be placed in a grid-connected mode;

[0020] In the grid-connected mode, the electric energy of the power generation unit is controlled to pass through the energy storage unit and then be output to the second bus, and then output to the load through the second bus.

[0021] Optionally, the control unit is configured as:

[0022] When the mains power returns to normal from abnormality, the power generation unit is controlled to transfer the load power to the energy storage unit. After the load power transfer is completed, the energy storage unit is controlled to be placed in an island mode. In the island mode, the energy storage unit is controlled to output electric energy to the second bus, and the second bus is output to the load.

[0023] Controlling the power generation unit to be disconnected from the first bus;

[0024] Controlling the first switch unit to close, connecting the mains power to the first busbar;

[0025] Controlling the mains power and the output voltage of the energy storage unit to perform synchronous phase locking, and after the synchronous phase locking is completed, controlling the energy storage unit to be placed in a grid-connected mode;

[0026] In the grid-connected mode, the energy storage unit is controlled to transfer the load power to the mains. After the load power transfer is completed, the electric energy of the first bus is controlled to pass through the energy storage unit and then output to the second bus, and then output to the load by the second bus.

[0027] Optionally, it further includes a third busbar, a fourth busbar, a first transformer unit, and a second transformer unit; the fourth switch unit includes a first switch module, a second switch module, and a third switch module; and the fifth switch unit includes a fourth switch module and a fifth switch module;

[0028] The third busbar is electrically connected to the first busbar through the first switch module;

[0029] The power generation unit is electrically connected to the third busbar through the second switch module, the energy storage unit is electrically connected to the third busbar through the third switch module, and the energy storage unit is electrically connected to the fourth busbar through the fourth switch module;

[0030] The fourth busbar is electrically connected to the second busbar through the fifth switch module;

[0031] The first transformer unit is used for voltage conversion between the first bus and the third bus, and the second transformer unit is used for voltage conversion between the fourth bus and the second bus.

[0032] Optionally, the first busbar is configured with a first mains input terminal and a second mains input terminal, and the first switch unit includes a sixth switch module and a seventh switch module;

[0033] The first mains power input terminal is electrically connected to the first busbar through the sixth switch module, and the second mains power input terminal is electrically connected to the first busbar through the seventh switch module;

[0034] The first busbar is further configured with a first section switch, and the first section switch is used to isolate the first mains input terminal and the second mains input terminal.

[0035] Optionally, the second bus is configured with a first load output terminal and a second load output terminal, and the second switch unit includes an eighth switch module and a ninth switch module;

[0036] The second busbar is electrically connected to the first load output terminal through the eighth switch module, and the second busbar is electrically connected to the second load output terminal through the ninth switch module;

[0037] The second busbar is further configured with a second section switch, and the second section switch is used to isolate the first load output end and the second load output end.

[0038] Optionally, the third busbar is further electrically connected to the fourth busbar through a sixth switch unit;

[0039] The sixth switch unit is configured to temporarily connect the third busbar and the fourth busbar when the energy storage unit is disconnected from the third busbar and the fourth busbar during maintenance.

[0040] Optionally, the first busbar is configured with a first voltage monitoring unit, the second busbar is configured with a second voltage monitoring unit, the third busbar is configured with a third voltage monitoring unit, and the fourth busbar is further configured with a fourth voltage monitoring unit.

[0041] Optionally, the power generation unit is a diesel power generation unit, and the energy storage unit is a flywheel energy storage unit.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention proposes a power supply system, which is provided with a backup power supply unit. When the mains power is abnormal, it can be switched to the backup power supply unit in time to ensure continuous power supply to the load and reduce power outages caused by mains power failures. Strong fault response capability: when the backup power supply unit itself is abnormal, the system can quickly disconnect it from the bus and close the third switch unit at the same time, so that the electric energy of the first bus is directly supplied to the second bus and the load, avoiding the failure of the backup power supply unit from affecting the entire power supply system and reducing the risk of large-scale power outages caused by the failure of a single component. The control unit can flexibly control each switch unit according to the different states of the mains power and the backup power supply unit to achieve switching of multiple power supply modes. When the mains power is normal, the electric energy can be controlled to be output after passing through the backup power supply unit, and the backup power supply unit may be used to optimize the processing of the electric energy in this process; when the mains power is abnormal or the backup power supply unit is abnormal, the power supply path can be quickly adjusted to ensure power supply to the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a structural block diagram of a power supply system in an embodiment;

[0044] Figure 2 is a structural block diagram of another power supply system in an embodiment;

[0045] Figure 3 Schematic diagram of the power supply system structure in the embodiment. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0047] Figure 1 This is a structural diagram of the power supply system in the embodiment, refer to Figure 1 The power supply system includes: a first busbar, a second busbar, a backup power supply unit 100 and a control unit 200.

[0048] The first busbar is configured to be connected to the mains through the first switch unit 301 , the second busbar is configured to be electrically connected to the load through the second switch unit 302 , and the first busbar and the second busbar are further connected in series through the third switch unit 303 .

[0049] The backup power supply unit 100 is electrically connected to the first busbar through the fourth switch unit 304 , and the backup power supply unit 100 is electrically connected to the second busbar through the fifth switch unit 305 .

[0050] In this solution, the control unit 200 is configured as follows:

[0051] When the mains power is normal, the electric energy of the first bus is controlled to pass through the backup power supply unit 100 and then output to the second bus, and then output to the load by the second bus.

[0052] When the mains power is abnormal, the mains power is disconnected by controlling the first switch unit 301 , and the backup power supply unit 100 is controlled to output electric energy to the second bus, which is then output to the load.

[0053] When the backup power supply unit 100 is abnormal, the fourth switch unit 304 and the fifth switch unit 305 are controlled to be disconnected, the backup power supply unit 100 is disconnected from the first bus and the second bus, and the third switch unit 303 is controlled to be closed. The electric energy output by the first bus is directly output to the second bus, and then output to the load by the second bus.

[0054] For example, in this solution, the first bus and the second bus are set to the same potential. When the backup power supply unit 100 fails or needs to be shut down for routine maintenance, the third switch unit 303 can be controlled to close so that the first bus directly supplies power to the second bus.

[0055] For example, in this solution, when the mains power is normal and the voltage is in the normal voltage range, the first busbar supplies power to the second busbar through the backup power supply unit 100. During this process, the functions of the backup power supply unit 100 mainly include: storing part of the electric energy output by the first busbar, and outputting the electric energy other than the stored energy to the second busbar.

[0056] For example, in this solution, when the mains power is abnormal and the voltage is outside the normal voltage range, the mains power is controlled to stop outputting electrical energy to the first bus. At this time, the functions of the backup power supply unit 100 mainly include: using the stored electrical energy to supply power to the second bus, or the backup power supply unit 100 uses additional energy to generate electricity, thereby supplying power to the second bus.

[0057] For example, in this solution, when the mains power is abnormal and the backup power supply unit 100 is used to power the second bus, the mains power is switched to the backup power supply unit 100, and the delay for the backup power supply unit 100 to start normally powering the second bus is less than 10 milliseconds.

[0058] For example, in this solution, for high-voltage and high-power electricity consumption scenarios, the backup power supply unit 100 can also be designed based on a (3~10kV) flywheel energy storage system. When the flywheel energy storage system needs to be charged and stored, the mains power grid supplies power to the load while also supplying power to the flywheel energy storage system for energy storage. After the energy storage is completed, the flywheel energy storage system enters an online hot standby state. When the mains power is abnormal, it can be switched to the flywheel energy storage system for power supply.

[0059] For example, in this solution, the control unit 200 or the backup power supply unit 100 can be configured to monitor the voltage of the AC power, the first bus, the second bus, and the load, and then determine the location where the voltage anomaly occurs, and execute the corresponding control logic according to the location of the voltage anomaly (for example, disconnecting the AC power, disconnecting the backup power supply unit, etc.).

[0060] Illustratively, in this solution, according to the hardware design of the backup power supply unit 100 , the control unit 200 configures corresponding control logic to make the power supply switching delay between the mains power and the backup power supply unit 100 less than 10 milliseconds.

[0061] For example, for a flywheel energy storage system, to achieve rapid switching, the control unit 200 controls the inverter in the power conversion system to synchronize the AC power output of the flywheel energy storage system with the mains power in terms of voltage amplitude, frequency, and phase. Phase-locked loop (PLL) technology is used to track the mains power phase in real time, ensuring that the phase difference between the flywheel energy storage system output and the mains power is less than a set value (e.g., ±5°).

[0062] When the control unit 200 detects a mains power anomaly, it quickly disconnects the first switch unit 301, severing the connection between the mains power and the first busbar. The control unit 200 controls the inverter in the power conversion system, rapidly converting the mechanical energy stored in the flywheel energy storage system into electrical energy in a pre-synchronized state, and then converting it into AC power that matches the voltage, frequency, and phase of the second busbar. This completes the switchover process from the mains power to the backup power supply unit.

[0063] When an abnormality occurs in the flywheel energy storage system, the control unit 200 issues a command to quickly disconnect the fourth and fifth switch units 304 and 305, isolating the flywheel energy storage system from the first and second busbars. Simultaneously, the third switch unit 303 is closed, allowing the power from the first busbar to be directly transferred to the second busbar, allowing the mains to continue supplying power to the load.

[0064] This embodiment proposes a power supply system, which is provided with a backup power supply unit. When the mains power is abnormal, it can be switched to the backup power supply unit in time to ensure continuous power supply to the load and reduce power outages caused by mains power failures. Strong fault response capability: when the backup power supply unit itself is abnormal, the system can quickly disconnect it from the busbar and close the third switch unit at the same time, so that the power of the first busbar is directly supplied to the second busbar and the load, avoiding the failure of the backup power supply unit from affecting the entire power supply system, and reducing the risk of large-scale power outages caused by the failure of a single component. The control unit can flexibly control each switch unit according to the different states of the mains power and the backup power supply unit to achieve switching of multiple power supply modes. When the mains power is normal, the power can be controlled to be output after passing through the backup power supply unit, and the backup power supply unit may be used to optimize the power processing in this process; when the mains power is abnormal or the backup power supply unit is abnormal, the power supply path can be quickly adjusted to ensure power supply to the load.

[0065] exist Figure 1 Based on the illustrated solution, in one possible implementation, the backup power supply unit includes a power generation unit and an energy storage unit; the power generation unit is coupled to the first bus, and the energy storage unit is coupled to the first bus and the second bus.

[0066] In this solution, the power generation unit is set to supply power to the load when the mains power is abnormal.

[0067] In this solution, the energy storage unit is set to store part of the electric energy output to the load when the mains or the power generation unit supplies power to the load, and to temporarily supply power to the load when the power generation unit and the mains are switched.

[0068] In this solution, the power generation unit is assumed to have only the function of generating electricity. For example, the power generation unit can be a diesel generator unit or a gas turbine generator unit. Gas turbine generators use combustible gases such as natural gas as fuel. The combustion of these gases produces high-temperature, high-pressure gas, which drives the gas turbine's impeller to rotate, which in turn drives the generator's rotor to rotate, cutting through magnetic flux lines to generate electricity.

[0069] For example, in this solution, to ensure that the power generation unit and the energy storage unit can be connected to the grid and provide power to the load through the bus, the power generation unit and the energy storage unit can also be configured as needed:

[0070] The voltage regulator is used to monitor the output voltage of the power generation unit in real time and control the output voltage to remain stable to meet the voltage requirements when connected to the grid.

[0071] The synchronization detection device is used to detect and compare the voltage, frequency and phase of the power generation unit and the power grid in real time to determine whether the grid connection conditions are met and provide a basis for closing operations.

[0072] The filter device is used to filter the output electric energy to improve the quality of electric energy and meet the grid connection requirements.

[0073] The power factor correction device is used to adjust the power factor of the power generation unit according to the requirements of the power grid by adding or removing capacitor banks, so that it matches the power factor of the power grid, thereby improving the efficiency of power transmission and the stability of power grid operation.

[0074] In this solution, the energy storage unit is designed to have both energy storage and power generation functions. When the energy storage unit is configured to generate electricity, it uses the stored energy to generate electricity. The energy storage unit can be a flywheel energy storage system or a battery storage system.

[0075] For example, in this solution, the power generation unit is coupled to the first busbar. The output of the power generation unit can be connected to a dedicated high-voltage switchgear (equipped with circuit breakers, disconnectors, current transformers, and other equipment) via a copper cable. The output of the high-voltage switchgear is connected to the first busbar via a busbar bridge or high-voltage cable.

[0076] For example, in this solution, the energy storage unit is coupled to the first busbar and the second busbar. The motor / generator in the energy storage unit can be connected to a bidirectional converter. Specifically, the DC side of the bidirectional converter is connected to the motor / generator, while the AC side is connected to the first busbar and the second busbar, respectively, via a circuit breaker and disconnector within the high-voltage switchgear.

[0077] Voltage transformers can also be installed on the first and second busbars to monitor busbar voltages. The voltage transformers provide voltage signals for overvoltage and undervoltage protection, as well as for synchronization (detection) devices in the energy storage units.

[0078] In this solution, to ensure that the power supply switching delay between the mains and the backup power supply unit is less than 10 milliseconds, the energy storage unit is used to temporarily power the load when the mains is cut off and the power generation unit is used to supply power to the load. This serves as a transition before the power generation unit is used to supply power, thereby avoiding the problem of load power interruption caused by the startup time of the power generation unit.

[0079] Based on the above solution in which the backup power supply unit includes a power generation unit and an energy storage unit, in one possible implementation scheme, the control unit is configured as follows:

[0080] When the mains power is abnormal, disconnecting the mains power by controlling the first switch unit;

[0081] The energy storage unit is controlled to be in an island mode. In the island mode, the energy storage unit is controlled to output electric energy to the second bus, and then output to the load via the second bus.

[0082] Control the power generation unit to start, control the output voltage of the power generation unit and the energy storage unit to synchronize and lock the phase. After the synchronization and locking are completed, control the energy storage unit to be placed in the grid-connected mode;

[0083] In the grid-connected mode, the electric energy of the power generation unit is controlled to pass through the energy storage unit and then output to the second bus, and then output to the load by the second bus.

[0084] In this solution, when the mains power is abnormal, the mains power is first disconnected, and then the energy storage unit is controlled to serve as a transitional power supply device to supply power to the load. After the power generation unit is ready for power generation and grid connection, the power generation unit is controlled to supply power to the load, and the energy storage unit stops supplying power to the load.

[0085] In this solution, the control unit continuously monitors the mains voltage amplitude and frequency through voltage and frequency sensors. When the mains voltage amplitude exceeds the normal range (e.g., below 90% or above 110% of the rated value), or the frequency deviation exceeds a specified value (e.g., ±0.5Hz), the control unit determines that the mains power is abnormal.

[0086] Once a mains power anomaly is detected, the control unit immediately sends a control signal to the first switch unit. This unit typically uses a fast-acting high-voltage circuit breaker. Upon receiving the signal, the first switch unit disconnects the mains power from the system within a very short time (e.g., 5 milliseconds), preventing the abnormal mains power from damaging the system's equipment and preventing the fault from spreading further.

[0087] The energy storage unit is placed in island mode. In island mode, it outputs power to the secondary bus, which then supplies it to the load. Island mode switching logic: While disconnecting the mains power, the control unit sends a command to the battery energy storage system's bidirectional converter, switching its operating mode to island mode. In island mode, the system no longer relies on the mains' synchronization signal, but instead autonomously controls the frequency, phase, and voltage amplitude of the output power. The energy storage unit inverts DC power into AC power and precisely adjusts the output voltage and frequency based on load demand and battery characteristics.

[0088] After the energy storage unit enters island mode, the control unit immediately issues a start command to the generator unit. The generator unit's starter motor begins operating, driving the engine. During the startup process, the automatic voltage regulator and speed governor come into play, adjusting the generator output voltage to gradually stabilize it near the rated value. The speed governor controls the engine speed to ensure frequency stability.

[0089] Once the generator unit is outputting stable electrical energy, the control unit begins synchronization and phase locking. Voltage and current transformers installed on the output lines of the generator and energy storage units collect their voltage and current signals in real time. A specialized synchronization device compares the amplitude, frequency, and phase of the output voltages of the generator and energy storage units. Based on the feedback signals, the control unit adjusts the diesel generator's speed regulator and the output parameters of the battery energy storage system to gradually bring the voltage amplitude, frequency, and phase of the two closer together. Synchronization and phase locking are considered complete when the amplitude difference is less than 5%, the frequency difference is less than 0.2 Hz, and the phase difference is less than 10°.

[0090] After synchronization and phase locking are completed, the control unit sends a command to the energy storage unit to switch its operating mode from island mode to grid-connected mode. In grid-connected mode, the energy storage unit can work in conjunction with the power generation unit to achieve stable output and distribution of electrical energy.

[0091] In grid-connected mode, the control unit controls the bidirectional converter to operate in rectifier-inverter mode. A portion of the AC power output by the power generation unit passes through the rectifier section of the bidirectional converter, converting it into DC power for energy storage. The AC power from the power generation unit passes through the switching circuit of the energy storage unit to form AC power that matches the second busbar and is output to the second busbar to power the load.

[0092] Based on the above solution in which the backup power supply unit includes a power generation unit and an energy storage unit, in one possible implementation scheme, the control unit is configured as follows:

[0093] When the utility power returns to normal, the power generation unit is controlled to transfer the load power to the energy storage unit. After the load power transfer is completed, the energy storage unit is controlled to be placed in island mode. In island mode, the energy storage unit is controlled to output power to the second bus, and then output to the load from the second bus.

[0094] Controlling the power generation unit to be disconnected from the first busbar;

[0095] Control the first switch unit to close and connect the mains power to the first busbar;

[0096] Control the output voltage of the mains and the energy storage unit to perform synchronous phase locking. After the synchronous phase locking is completed, the energy storage unit is controlled to be placed in grid-connected mode;

[0097] In the grid-connected mode, the energy storage unit is controlled to transfer the load power to the mains. After the load power transfer is completed, the electric energy of the first bus is controlled to pass through the energy storage unit and then output to the second bus, and then output to the load by the second bus.

[0098] In this solution, when the mains power returns to normal, the power generation unit is first controlled to transfer the load power to the energy storage unit. The energy storage unit is then controlled to supply power to the load as a transitional power supply device. After the mains power is ready for grid connection, the mains power is controlled to supply power to the load, and the energy storage unit stops supplying power to the load.

[0099] In this solution, the control unit continuously monitors the mains voltage amplitude and frequency via a voltage sensor and a frequency sensor. When the mains voltage amplitude returns to a normal range (e.g., between 95% and 105% of the rated value) and the frequency stabilizes at a specified value (e.g., 50Hz±0.2Hz), the control unit determines that the mains power has returned to normal.

[0100] The control unit sends instructions to the generator unit, gradually reducing its output power. Simultaneously, it controls the bidirectional converter in the energy storage unit, causing it to begin increasing its output power. During this process, current sensors installed on the secondary busbar monitor the load current in real time, ensuring smooth power transfer from the diesel generator to the battery energy storage system.

[0101] Once the load power has been fully transferred to the energy storage unit, the control unit sends a command to the energy storage unit, switching its operating mode to island mode. In island mode, the bidirectional converter precisely adjusts the output voltage and frequency based on the load demand. After confirming that the load power has been fully transferred to the energy storage unit and that the energy storage unit has entered island mode and is providing stable power, the control unit sends a disconnect command to the switchgear connecting the diesel generator to the primary busbar.

[0102] After confirming that the power generation unit has been disconnected from the first busbar, the control unit sends a closing instruction to the first switch unit. After receiving the instruction, the high-voltage circuit breaker of the first switch unit closes and connects the mains power to the first busbar.

[0103] The control unit collects the voltage and current signals from the mains and energy storage unit outputs in real time through voltage and current transformers installed on the mains input and energy storage unit output lines. Simultaneously, a dedicated synchronization device is activated to prepare for phase-locked synchronization. This synchronization device compares the amplitude, frequency, and phase of the mains and energy storage unit output voltages. Based on the feedback signals, the control unit adjusts the output parameters of the bidirectional converter, such as by adjusting the inverter's trigger pulses to change the phase and amplitude of the output voltage, gradually aligning the voltage amplitude, frequency, and phase of the two. Phase-locked synchronization is considered complete when the amplitude difference is less than 3%, the frequency difference is less than 0.1 Hz, and the phase difference is less than 5°.

[0104] After synchronization and phase locking are completed, the control unit sends a command to the energy storage unit to switch its operating mode from island mode to grid-connected mode. In grid-connected mode, the energy storage unit can work in conjunction with the mains to achieve stable output and distribution of electrical energy.

[0105] In grid-connected mode, the energy storage unit is controlled to transfer load power to the mains. Once the load power transfer is complete, the power from the first bus is controlled to pass through the energy storage unit and then to the second bus, from which it is then delivered to the load. The control unit sends instructions to the energy storage unit, gradually reducing its output power until it reaches zero, and the load power is entirely borne by the mains.

[0106] After the load power is fully transferred to the mains, the control unit switches the bidirectional converter to rectifier-inverter mode. After the mains power is connected to the first bus, a portion of its AC output is converted to DC through the rectifier section of the bidirectional converter. The energy storage unit then stores energy. After the AC power from the first bus passes through its switching circuit, it is converted into AC power that matches the second bus and outputs it to the second bus, ensuring a continuous and stable supply of high-quality power to the load.

[0107] Figure 2 This is another structural block diagram of the power supply system in the embodiment, refer to Figure 2 Based on any of the foregoing schemes, in one feasible implementation scheme, the power supply system further includes a third bus, a fourth bus, a first transformer unit 41, and a second transformer unit 42; the fourth switch unit includes a first switch module 3041, a second switch module 3042, and a third switch module 3043; and the fifth switch unit includes a fourth switch module 3051 and a fifth switch module 3052.

[0108] The third busbar is electrically connected to the first busbar through the first switch module 3041 (and the first transformer unit 41 ).

[0109] The power generation unit 101 is electrically connected to the third busbar through the second switch module 3042 , the energy storage unit 102 is electrically connected to the third busbar through the third switch module 3043 , and the energy storage unit 102 is electrically connected to the fourth busbar through the fourth switch module 3051 .

[0110] The fourth busbar is electrically connected to the second busbar through the fifth switch module 3052 (and the second transformer unit 42 ).

[0111] The first transformer unit 41 is used for voltage conversion between the first busbar and the third busbar, and the second transformer unit 42 is used for voltage conversion between the fourth busbar and the second busbar.

[0112] For example, in this solution, based on the voltage level difference between the power generation unit 101, the energy storage unit 102 and the mains, the first bus, the second bus, the third bus and the fourth bus are designed to form a multi-level bus network, the first bus and the second bus are designed to have an equal potential, the first bus can be connected to high voltage electricity, and the third bus and the fourth bus are designed to have an equal potential.

[0113] By electrically connecting the power generation unit 101 and the energy storage unit 102 to the third busbar, a first transformer unit 41 is provided between the first busbar and the third busbar, and voltage conversion between the first busbar and the third busbar is achieved through the first transformer unit 41, so that the voltage level of the third busbar matches the input voltage level of the power generation unit 101 and the energy storage unit 102. A second transformer unit 42 is provided between the fourth busbar and the second busbar, and voltage conversion between the fourth busbar and the second busbar is achieved through the second transformer unit 42, so that the voltage level output to the load matches the load's power demand (high voltage, high power, etc.).

[0114] In this solution, the third busbar gathers power from multiple power generation units. The power output from these units is then distributed to the fourth busbar via the energy storage unit and further distributed to the loads. This configuration allows for more flexible power flow and facilitates the rational scheduling of power resources. The multi-busbar structure facilitates access to a variety of power sources and loads, and can flexibly adjust the flow and distribution of power according to varying operational needs.

[0115] In addition, when a fault occurs in a part of the system, by controlling the corresponding switch, the fault can be isolated in a specific bus area, preventing the fault from spreading to the entire system and improving system reliability.

[0116] Illustratively, in this solution, the first switch module 3041 is used to disconnect the first busbar and the second busbar when the mains power is abnormal, and to connect the first busbar and the third busbar when the mains power returns to normal.

[0117] Exemplarily, in this solution, the second switch module 3042 is used to connect the power generation unit 101 to the third bus when the power generation unit 101 is needed to power the load, and disconnect the power generation unit 101 from the third bus when the power generation unit 101 is not needed to power the load.

[0118] For example, in this solution, the third switch module 3043 and the fourth switch module 3051 are used to disconnect the energy storage module 102 from the power grid when the energy storage module 102 fails or needs to be shut down for routine maintenance, and to connect the energy storage module 102 to the power grid when the energy storage module 102 is operating normally.

[0119] Exemplarily, in this solution, the fifth switch module 3052 is used to disconnect the fourth bus and the second bus when the voltage on the fourth bus or the second bus is abnormal, and to connect the fourth bus and the second bus when AC power, the power generation unit 101 or the energy storage unit 102 is used to supply power to the load through the fourth bus.

[0120] Based on any of the foregoing solutions, in one possible implementation, the first busbar is configured with a first mains power input terminal and a second mains power input terminal, and the first switch unit includes a sixth switch module and a seventh switch module.

[0121] The first mains power input terminal is electrically connected to the first busbar through the sixth switch module, and the second mains power input terminal is electrically connected to the first busbar through the seventh switch module.

[0122] The first busbar is further configured with a first section switch, and the first section switch is used to isolate the first mains power input terminal and the second mains power input terminal.

[0123] In this solution, mains power flows from the first mains terminal (Feeder 1) through the sixth switch module to the first busbar. Mains power flows from the second mains terminal (Feeder 2) through the seventh switch module to the first busbar. A first sectionalizing switch is installed on both transmission lines on the first busbar to provide emergency closure in the event of equipment failure on both lines.

[0124] For example, in this solution, a voltage conversion unit (e.g., T1) and a voltage transformer (e.g., PT1) may be configured on the first mains terminal and the first busbar, respectively. A voltage conversion unit (e.g., T2) and a voltage transformer (e.g., PT2) may be configured on the second mains terminal and the first busbar, respectively.

[0125] For example, in this solution, the control unit or energy storage unit can be configured to determine whether Feeder 1 is normal by detecting the closed state of the sixth switch module on the Feeder 1 side, the normal state feedback of T1, and the current real-time voltage feedback of this section of the first busbar by PT1. Whether Feeder 2 is normal can be determined by detecting the closed state of the seventh switch module on the Feeder 2 side, the normal state feedback of T2, and the current real-time voltage feedback of this section of the first busbar by PT2.

[0126] When an abnormality is detected in a certain mains power line, the corresponding sixth switch module or seventh switch module on its side is disconnected, thereby disconnecting the abnormal power supply branch from the third bus; when the maintenance is completed and reset, the corresponding sixth switch module or seventh switch module is reclosed to achieve dual-line redundant power supply for this section.

[0127] Based on any of the foregoing solutions, in one possible implementation, the second bus is configured with a first load output terminal and a second load output terminal, and the second switch unit includes an eighth switch module and a ninth switch module.

[0128] The second busbar is electrically connected to the first load output terminal through the eighth switch module, and the second busbar is electrically connected to the second load output terminal through the ninth switch module.

[0129] The second busbar is further configured with a second section switch, and the second section switch is used to isolate the first load output end and the second load output end.

[0130] Exemplarily, in this solution, a second section switch is installed on the second busbar, which is used to isolate the sections when a load device fails or during routine operation and maintenance.

[0131] For example, in this solution, a voltage transformer (e.g., PT3) can be configured on the second bus at the first load output terminal (load1). PT3 monitors the voltage on the second bus at the first load output terminal. A voltage transformer (e.g., PT4) can be configured on the second bus at the second load output terminal (load2). PT4 monitors the voltage on the second bus at the second load output terminal.

[0132] For example, in this solution, the control unit or energy storage unit can be configured to determine whether load 1 is normal by detecting the current real-time voltage of the second bus section fed back by PT3. Determine whether load 2 is normal by detecting the current real-time voltage of the second bus section fed back by PT3.

[0133] When an abnormal load is detected on a certain line, the eighth switch module or the ninth switch module corresponding to the side is disconnected, thereby disconnecting the abnormal power supply branch from the fourth bus; when the maintenance is completed and reset, the corresponding eighth switch module or the ninth switch module is reclosed to realize dual-line redundant power supply for this section.

[0134] refer to Figure 2 In one possible implementation scheme, the third bus is also electrically connected to the fourth bus through a sixth switch unit 306 .

[0135] The sixth switch unit 306 is configured to temporarily connect the third busbar and the fourth busbar when the energy storage unit 102 is disconnected from the third busbar and the fourth busbar for maintenance.

[0136] Illustratively, in this solution, the energy storage unit 102 is configured to include a static bypass, which is configured to provide a bypass channel for power transmission, thereby enabling contactless power switching and rapid response to system requirements.

[0137] For example, in a flywheel energy storage system, during normal operation, the system's motor / generator is connected to the grid via an inverter, enabling bidirectional conversion of electrical energy. If the inverter fails, is overloaded, or requires maintenance, the power electronic switches (such as thyristors) in the static bypass quickly conduct, isolating the motor / generator from the inverter and connecting it directly to the grid. This allows the system to continue operating and avoids system downtime caused by inverter problems.

[0138] Exemplarily, in this solution, the control unit may be configured as:

[0139] When a fault in the energy storage unit is detected, the static bypass is controlled to be closed, and the sixth switch unit 306 is controlled to be closed;

[0140] After the sixth switch unit 306 is confirmed, the static bypass and the third switch module 3043 and the fourth switch module 3051 are disconnected, thereby disconnecting the electrical connection between the energy storage unit 102 and the grid and the load, facilitating troubleshooting and maintenance work.

[0141] Based on the aforementioned power supply system, which includes a first busbar, a second busbar, a third busbar and a fourth busbar, in one feasible implementation scheme, the first busbar is configured with a first voltage monitoring unit, the second busbar is configured with a second voltage monitoring unit, the third busbar is configured with a third voltage monitoring unit, and the fourth busbar is also configured with a fourth voltage monitoring unit.

[0142] Exemplarily, in this solution, the control unit can be configured to determine whether the first bus voltage is normal through the real-time voltage fed back by the first voltage monitoring unit, determine whether the second bus voltage is normal through the real-time voltage fed back by the second voltage monitoring unit, determine whether the third bus voltage is normal through the real-time voltage fed back by the third voltage monitoring unit, and determine whether the fourth bus voltage is normal through the real-time voltage fed back by the fourth voltage monitoring unit. When an abnormal bus voltage is detected, the corresponding switch module or switch unit on its side is disconnected to isolate the fault.

[0143] Based on any of the foregoing solutions, in one possible implementation, the power generation unit is a diesel power generation unit, and the energy storage unit is a flywheel energy storage unit.

[0144] Figure 3 This is a schematic diagram of the power supply system structure in the embodiment, refer to Figure 3 Based on any of the above solutions, in one possible implementation scheme, the power supply system includes:

[0145] The first busbar, the second busbar, the third busbar, the fourth busbar, the first diesel generator set G1, the second diesel generator set G2, and the flywheel energy storage system.

[0146] The first busbar is equipped with a first mains input terminal Feeder1 and a second mains input terminal Feeder2. The first mains input terminal is electrically connected to the first busbar through a first switch K11, and the second mains input terminal Feeder2 is electrically connected to the first busbar through a second switch K12. A first section switch K13 is also configured between the first mains input terminal Feeder1 and the second mains input terminal Feeder2.

[0147] The first busbar is electrically connected to the third busbar through the third switch K14, the first transformer T1, and the fourth switch K31. The first busbar is electrically connected to the third busbar through the fifth switch K15, the second transformer T2, and the sixth switch K32. The first busbar is also configured with a first voltage transformer PT1 and a second voltage transformer PT2.

[0148] The first diesel generator set G1 is electrically connected to the third busbar via the seventh switch K33, and the second diesel generator set G2 is electrically connected to the third busbar via the eighth switch K34. The third busbar is also equipped with a third voltage transformer PT11.

[0149] The third busbar is also electrically connected to the fourth busbar via a ninth switch K41.

[0150] The flywheel energy storage system includes multiple charging and discharging branches and a static bypass. Among them, one charging and discharging branch includes a thyristor switch, an electric motor / generator and a bidirectional converter. The thyristor switch and the inductor constitute a thyristor switch circuit. The third bus is connected to the fourth bus through the switch and the thyristor switch circuit. The electric motor / generator is electrically connected to the thyristor switch circuit through the bidirectional converter.

[0151] Specifically, the third bus is electrically connected to the fourth bus through the tenth switch K35, the first thyristor SW1, the inductor, and the eleventh switch K36, and the first motor / generator FW1 is electrically connected to the first thyristor switch circuit through the bidirectional converter, the transformer, and the switch.

[0152] The third bus is electrically connected to the fourth bus through the twelfth switch K37, the second thyristor SW2, the inductor, and the thirteenth switch K38. The second motor / generator FW2 is electrically connected to the second thyristor switch circuit through the bidirectional converter, the transformer, and the switch.

[0153] The third busbar is electrically connected to the fourth busbar through the fourteenth switch K39 , the third thyristor SW, and the fifteenth switch K40 , and the third thyristor SW forms a static bypass.

[0154] The fourth bus is electrically connected to the second bus through the sixteenth switch K42, the third transformer T3, and the seventeenth switch tube K18. The fourth bus is electrically connected to the second bus through the eighteenth switch K43, the fourth transformer T4, and the nineteenth switch K19. The fourth bus is also equipped with a fourth voltage transformer PT12.

[0155] The second busbar is electrically connected to the first load output terminal load1 through the 20th switch tube K20, and the second busbar is electrically connected to the second load output terminal load2 through the 21st switch tube K21. A second section switch K23 is also configured between the first load output terminal load1 and the second load output terminal load2. The second busbar is also configured with a fifth voltage transformer PT3 and a sixth voltage transformer PT4.

[0156] The first busbar is also electrically connected to the second busbar through the twenty-second switch K16 and the twenty-third switch K17.

[0157] In this embodiment, the first switch K11 and the second switch K12 are included in the first switch unit. The third switch K14, the fifth switch K15, the fourth switch K31, and the sixth switch K32 are included in the first switch module. The seventh switch K33 and the eighth switch K34 are included in the second switch module. The fourteenth switch K39, the twelfth switch K37, and the tenth switch K35 are included in the third switch module. The ninth switch K41 is included in the sixth switch unit. The eleventh switch K36, the thirteenth switch K38, and the fifteenth switch K40 are included in the fourth switch module. The sixteenth switch K42, the eighteenth switch K43, the seventeenth switch K18, and the nineteenth switch K19 are included in the fifth switch module. The twentieth switch K20 and the twenty-first switch K21 are included in the second switch unit. The twenty-second switch K16 and the twenty-third switch K17 are included in the third switch unit.

[0158] In this solution, the utility power from Feeder 1 and Feeder 2 is fed through K11 and K12, respectively, to the first busbar. A first sectionalizing switch, K13, is installed on the first busbar, connecting the two transmission lines. Normally, it is in sectionalizing mode, and is used for emergency closure in the event of equipment failure on both lines.

[0159] The downstream of the first busbar includes K14 and K15, which are transformed by their respective transformers T1 and T2, and then converged to the third busbar through K31 and K32. At the same time, PT1 and PT2 are installed on the first busbar, which are used for voltage monitoring on the first busbar.

[0160] The third busbar is the core of the system. G1, G2, flywheel energy storage system FW and the associated high-voltage switchgear are all connected to this busbar. At the same time, a PT11 is installed on the third busbar for voltage monitoring on this busbar.

[0161] Whether the mains electricity is converged to the third busbar via the first busbar, or the self-generated electricity of G1 and G2 is converged to the third busbar, it must be converged to the fourth busbar via the flywheel energy storage system FW and the associated high-voltage switchgear. The third busbar and the fourth busbar have the same potential. At the same time, a PT12 is installed on the fourth busbar for voltage monitoring on this busbar.

[0162] The downstream of the fourth busbar consists of two lines K42 and K43, which are transformed by their respective transformers T3 and T4, and then converge to the second busbar through K18 and K19. The second busbar has the same potential as the first busbar.

[0163] A second section switch K23 is installed on the second busbar on the two transmission lines to play a section isolation role when a fault occurs in one of the line equipment or during routine operation and maintenance. At the same time, a PT3 is installed on the second busbar for voltage monitoring on this busbar. The second busbar downstream supplies power to the load through the two lines K20 and K21.

[0164] The first busbar and the second busbar are connected through K16 and K17, which are used to connect the first busbar and the second busbar when the diesel generator set and the flywheel energy storage system fail or undergo operation and maintenance to ensure uninterrupted power supply to the load.

[0165] In this solution, when using mains power supply, two mains power lines are used for redundant power supply. Any one of the mains power lines can supply power to the load normally. At this time, the diesel generator set is in standby mode and the flywheel energy storage system is in online mode.

[0166] The flywheel energy storage system determines whether Feeder 1 is functioning properly by checking the closed state of K14 on Feeder 1, the normal feedback state of T1, and the current real-time voltage of this section of the first busbar fed back by PT1. The flywheel energy storage system determines whether Feeder 2 is functioning properly by checking the closed state of K15 on Feeder 2, the normal feedback state of T2, and the current real-time voltage of this section of the first busbar fed back by PT2.

[0167] When an abnormality is detected in a certain mains power line, the corresponding K31 or K32 on its side is disconnected, the connection between the abnormal power supply branch and the third bus is disconnected, and the corresponding fault information is reported; when the maintenance is completed and reset, the corresponding mains power switch K31 or K32 is reclosed to realize dual-line redundant power supply for this section.

[0168] The mains electricity flows from the third busbar through the flywheel energy storage system's SW1 and SW2 and the corresponding high-voltage switches K35, K36, K37, and K38 to the fourth busbar. At the same time, it stores energy in the flywheel energy storage system's FW1 and FW2 through the bidirectional converter and transformer. After the energy storage is completed, the flywheel energy storage system enters the online hot standby state to realize abnormal switching within the city.

[0169] All switches downstream of the fourth bus and the second bus are in the closed state, realizing dual redundant power supply in this section. If a load device fails, the abnormal power supply branch is disconnected from the fourth bus and the corresponding fault information is reported.

[0170] In this solution, when the mains power is abnormal, the control unit monitors the voltage on the third busbar in real time. If this occurs, a switchover from mains power to the diesel generator set is necessary. Diesel generator sets start slowly, so to ensure uninterrupted power supply to the load, a flywheel energy storage system is used to provide a transitional power supply during the switchover between mains power and diesel generator set power.

[0171] When the control unit detects an abnormal voltage on the third bus, it sends a command to the flywheel energy storage system to switch to VF (off-grid / island mode). The switch is completed within 10 milliseconds, and the flywheel energy storage system immediately supplies power to the downstream load. Simultaneously, the control unit closes SW1 and SW2, quickly disconnecting the flywheel energy storage system from the third bus.

[0172] The control unit sends a disconnection command to K31 and K32; after receiving the disconnection feedback from K31 and K32, the control unit sends a start command to the diesel generator set.

[0173] The flywheel energy storage system is phase-locked with the output voltage of the diesel generator set. After the synchronization is completed, the flywheel energy storage system is ready for grid-connected operation with the diesel generator. The control unit controls the closing of SW1 and SW2. At the same time, the control unit sends a PQ (grid-connected mode) working mode instruction to the flywheel energy storage system. The control unit gradually transfers the load to the diesel generator set according to the set slope, completing a seamless switch from power supply of the flywheel energy storage system to power supply of the diesel generator set.

[0174] After the load transfer is completed, the flywheel energy storage system begins to recharge and store energy.

[0175] In this solution, when the mains power returns to normal after an abnormality and the diesel generator set supplies power, the control unit continuously monitors the mains power recovery status and simultaneously determines the charging status of the flywheel energy storage system. When it detects that either of the two mains power lines has returned to normal and has remained normal for a certain period of time, and the flywheel energy storage system has also completed the energy storage operation, the system begins to switch from control unit power supply mode to mains power supply mode.

[0176] The control unit gradually transfers the load from the diesel generator set to the flywheel energy storage system at a set slope (subject to certain power requirements to avoid sudden unloading of the diesel generator set). Once the load transfer requirements are met, the control unit closes SW1 and SW2, quickly disconnecting the flywheel energy storage system from the diesel generator set.

[0177] The control unit sends a VF (off-grid / island mode) operating mode command to the flywheel energy storage system, which then supplies power to the load independently. The control unit sends a disconnect signal to the diesel generator set and detects whether K33 and K34 are in the open state.

[0178] The control unit sends a closing command to K31 or (and) K32 according to the restored mains power supply branch (detecting PT1 and PT2); the flywheel energy storage system is synchronously locked with the second bus voltage. After the synchronization is completed, it has the conditions for grid-connected operation with the mains power. After the grid-connected conditions are met, the control unit closes SW1 and SW2, and the control system sends a PQ (grid-connected mode) working mode command to the flywheel energy storage system.

[0179] The flywheel energy storage system gradually transfers the load to the mains according to the set slope, completing the seamless switch from flywheel energy storage power supply to mains power supply.

[0180] During the transfer process from diesel generator set power supply to mains power supply, if there are special circumstances that affect the transfer due to abnormal switch operation, excessive grid fluctuation, or failure of the flywheel energy storage system to synchronize with the mains power, the system will terminate the transfer to the mains power supply, resend the diesel generator set start signal, and execute the aforementioned logic of switching to the diesel generator set when the mains power is abnormal. The diesel generator set will continue to supply power, and will try to transfer to the mains power supply again after the fault is eliminated and reset.

[0181] The control unit detects the seamless switching and load transfer from the flywheel energy storage system to the mains power supply. After completion, the flywheel energy storage system starts to recharge and store energy. When the flywheel system finishes storing energy, it sends a shutdown command to the diesel generator set after a delay.

[0182] In this solution, when the flywheel energy storage system needs maintenance and the control unit detects a serious fault in the flywheel energy storage system, the control unit immediately turns off SW1 and SW2, quickly cutting off the connection between the faulty part of the flywheel energy storage system and the power grid; at the same time, it sends a closing command to SW and K41 that are in the off state.

[0183] After the control unit confirms that SW and K41 are closed, it disconnects SW to achieve seamless switching from online mode to maintenance bypass; then the control unit disconnects K35, K36, K37, K38, K39 and K40, disconnecting the electrical connection between the flywheel energy storage system and the power grid and load, to facilitate troubleshooting and maintenance work.

[0184] In this solution, power is supplied directly from the first busbar to the second busbar in critical situations. This refers to situations where the third or fourth busbar must be disconnected due to a fault or maintenance issue. In these critical situations, the control unit closes K16 and K17, allowing power to be supplied from the first busbar to the load via the second busbar.

[0185] In this solution, by configuring a flywheel energy storage system and a diesel generator set, and by using the flywheel energy storage system for power transition during the switching process from the mains to the diesel generator set, the emergency unit power supply system's rapid conversion time is improved, enabling seamless power switching in milliseconds. By configuring a multi-level busbar and using a transformer to achieve voltage conversion from the input to the output, the input voltage busbar can be connected to high voltage electricity, resolving the problem of commercial UPS power supplies not meeting the high-voltage, high-power power level requirements. In this solution, the first busbar of the power supply system is configured with multiple voltage output terminals, and the second busbar is configured with multiple voltage output terminals. The first busbar and the second busbar are also each equipped with a sectioning switch, achieving a redundant power supply line solution for the load, with high reliability. In this solution, the first busbar and the fourth busbar can also be directly connected. When the diesel generator set or flywheel energy storage system is disconnected from the grid, power is directly supplied to the second busbar via the first busbar. This allows for operation and maintenance of any power supply device while the load is continuously powered, ensuring on-site operation and product maintenance, improving product utilization efficiency, and reducing operating costs.

[0186] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A power supply system, characterized in that: include: A first busbar, a second busbar, a backup power supply unit and a control unit; The first busbar is configured to be connected to the mains through a first switch unit, the second busbar is configured to be electrically connected to the load through a second switch unit, and the first busbar and the second busbar are further connected in series through a third switch unit; The backup power supply unit is electrically connected to the first busbar through the fourth switch unit, and the backup power supply unit is electrically connected to the second busbar through the fifth switch unit; The control unit is configured as follows: When the mains power is normal, the electric energy of the first bus is controlled to pass through the backup power supply unit and then be output to the second bus, and then be output to the load by the second bus; When the mains power is abnormal, the first switch unit is controlled to disconnect the mains power, and the backup power supply unit is controlled to output electric energy to the second bus, and the second bus is used to output electric energy to the load; When the backup power supply unit is abnormal, the fourth switch unit and the fifth switch unit are controlled to be disconnected, the backup power supply unit is disconnected from the first bus and the second bus, the third switch unit is controlled to be closed, and the electric energy output by the first bus is directly output to the second bus, and then output to the load by the second bus.

2. The power supply system according to claim 1, wherein: The backup power supply unit includes a power generation unit and an energy storage unit; The power generation unit is coupled to the first bus, and the energy storage unit is coupled to the first bus and the second bus; The power generation unit is used to supply power to the load when the mains power is abnormal; The energy storage unit is used to store part of the electric energy output to the load when the mains power or the power generation unit supplies power to the load, and to temporarily supply power to the load when the power generation unit and the mains power are switched.

3. The power supply system according to claim 2, wherein: The control unit is configured as follows: When the mains power is abnormal, disconnecting the mains power by controlling the first switch unit; Controlling the energy storage unit to be in an island mode, and in the island mode, controlling the energy storage unit to output electric energy to the second bus, and outputting electric energy from the second bus to the load; Controlling the power generation unit to start, controlling the power generation unit to perform synchronous phase locking with the output voltage of the energy storage unit, and after the synchronous phase locking is completed, controlling the energy storage unit to be placed in a grid-connected mode; In the grid-connected mode, the electric energy of the power generation unit is controlled to pass through the energy storage unit and then be output to the second bus, and then output to the load through the second bus.

4. The power supply system according to claim 2, wherein: The control unit is configured as follows: When the mains power returns to normal from abnormality, the power generation unit is controlled to transfer the load power to the energy storage unit. After the load power transfer is completed, the energy storage unit is controlled to be placed in an island mode. In the island mode, the energy storage unit is controlled to output electric energy to the second bus, and the second bus is output to the load. Controlling the power generation unit to be disconnected from the first bus; Controlling the first switch unit to close, connecting the mains power to the first busbar; Controlling the mains power and the output voltage of the energy storage unit to perform synchronous phase locking, and after the synchronous phase locking is completed, controlling the energy storage unit to be placed in a grid-connected mode; In the grid-connected mode, the energy storage unit is controlled to transfer the load power to the mains. After the load power transfer is completed, the electric energy of the first bus is controlled to pass through the energy storage unit and then output to the second bus, and then output to the load by the second bus.

5. The power supply system according to claim 2, wherein: It also includes a third busbar, a fourth busbar, a first transformer unit, and a second transformer unit. The fourth switch unit includes a first switch module, a second switch module, and a third switch module. The fifth switch unit includes a fourth switch module and a fifth switch module. The third busbar is electrically connected to the first busbar through the first switch module; The power generation unit is electrically connected to the third busbar through the second switch module, the energy storage unit is electrically connected to the third busbar through the third switch module, and the energy storage unit is electrically connected to the fourth busbar through the fourth switch module; The fourth busbar is electrically connected to the second busbar through the fifth switch module; The first transformer unit is used for voltage conversion between the first bus and the third bus, and the second transformer unit is used for voltage conversion between the fourth bus and the second bus.

6. The power supply system according to claim 1, wherein: The first busbar is configured with a first mains input terminal and a second mains input terminal, and the first switch unit includes a sixth switch module and a seventh switch module; The first mains power input terminal is electrically connected to the first busbar through the sixth switch module, and the second mains power input terminal is electrically connected to the first busbar through the seventh switch module; The first busbar is further configured with a first section switch, and the first section switch is used to isolate the first mains input terminal and the second mains input terminal.

7. The power supply system according to claim 1, wherein: The second bus is configured with a first load output terminal and a second load output terminal, and the second switch unit includes an eighth switch module and a ninth switch module; The second busbar is electrically connected to the first load output terminal through the eighth switch module, and the second busbar is electrically connected to the second load output terminal through the ninth switch module; The second busbar is further configured with a second section switch, and the second section switch is used to isolate the first load output end and the second load output end.

8. The power supply system according to claim 5, wherein: The third busbar is also electrically connected to the fourth busbar via a sixth switch unit; The sixth switch unit is configured to temporarily connect the third busbar and the fourth busbar when the energy storage unit is disconnected from the third busbar and the fourth busbar during maintenance.

9. The power supply system according to claim 5, wherein: The first busbar is configured with a first voltage monitoring unit, the second busbar is configured with a second voltage monitoring unit, the third busbar is configured with a third voltage monitoring unit, and the fourth busbar is further configured with a fourth voltage monitoring unit.

10. The power supply system according to claim 2, wherein: The power generation unit adopts a diesel power generation unit, and the energy storage unit adopts a flywheel energy storage unit.

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