Medium voltage solid state transformer for aidc, system and online replacement method

Abstract

The application relates to the technical field of power supply, in particular to a medium-voltage solid-state transformer, a system and an online replacement method suitable for AIDC. The application comprises multiple power units and mode switching devices. The AC access ends of the power units are respectively connected in parallel to an external medium-voltage AC bus through the mode switching devices. The mode switching devices have four states of pre-charging, switching on, discharging and grounding. The power units can be independently inserted into or pulled out of the transformer. The power units are provided with a first low-voltage side port and a second low-voltage side port, and the second low-voltage side port is connected with an energy storage unit. The application further discloses a power unit online replacement method, which comprises fault detection, fault exit, fault pull-out, new unit insertion and new unit input. The application realizes the online safe replacement of the power units under the premise of uninterrupted 10kV power supply, has the functions of energy storage direct connection and seamless standby power switching, the switching time is less than 4ms, and the application can meet the requirement of 99.999% power supply reliability of the AIDC data center.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, specifically to a medium-voltage solid-state transformer, system, and online replacement method suitable for AIDC. Background Technology

[0002] Scene technology In the current wave of digitalization sweeping the globe, computing power has become the core productive force of the digital economy, and the AIDC (Artificial Intelligence Data Center) industry, as a core infrastructure of the digital economy, is booming at an unprecedented pace. The rapid expansion of data center scale and the continuous increase in equipment power density have brought new challenges to power supply architecture.

[0003] The traditional power supply mode is as follows: AC 10kV bus → power frequency transformer (step-down) → AC 380V → UPS rectification and inversion → 220V AC → server rectification → server internal DC load. This mode involves multiple conversions, with each stage incurring a loss of 1% to 3%, resulting in an overall efficiency of less than 92%.

[0004] As the power consumption of a single cabinet increases from several kilowatts to tens of kilowatts or even higher, the drawbacks of traditional power supply modes—low output voltage and high current—become increasingly apparent. When the power consumption of a single cabinet increases from 8kW to 120kW and the output voltage is 220V, the current surges from approximately 36A to 545A. This enormous current generates significant heat loss in the transmission lines, resulting in severe energy waste, placing immense pressure on the power distribution system, increasing the difficulty of cable laying and switch selection, and even posing safety hazards. With the further development of the AIDC industry, this power supply mode cannot meet the demands for higher power density.

[0005] Medium-voltage solid-state transformers (MV-SSTs) are a new type of power equipment integrating power electronics and intelligent control technologies. Unlike traditional AC 10kV / 380V power frequency transformers, they can achieve efficient bidirectional energy conversion between AC 10kV power from the grid and flexible DC 800V power supply buses. They reduce volume by 70%–90% and increase efficiency to over 98.5%, thus reconstructing the underlying logic of the power system. MV-SSTs are a concrete implementation of solid-state transformers (SSTs) at voltage levels from 10kV to 35kV, serving as the power distribution entry point for high power density applications.

[0006] With the adoption of a medium-voltage solid-state transformer (SST), the typical power supply mode is as follows: 10kV medium-voltage AC power → medium-voltage solid-state transformer → 800V high-voltage DC power (HVDC) → server power supply (further step-down) → low-voltage DC power to the server. In other words, SST replaces the UPS rectification and inversion and server rectification stages in the traditional power supply mode, significantly reducing the number of conversions and improving system efficiency.

[0007] Currently, the industry mostly adopts an input series-output parallel (ISOP) architecture voltage splitting scheme to achieve MV-SST in medium and large capacity applications. This scheme completes power conversion through three stages: the first stage uses a cascaded H-bridge converter (CHB) to achieve AC 10kV voltage division and AC / DC conversion; the second stage converts low-voltage DC to high-frequency AC of tens of kHz; the third stage uses a high-frequency transformer for electrical isolation and transformation, and finally rectifies it to low-voltage DC and outputs it in parallel, as shown in the invention patent with publication number CN120433595A.

[0008] In existing technology, the structural principle of medium-voltage solid-state transformers is as follows: Figure 1 As shown: Multiple power units are connected in series on a 10kV bus, with each power unit sharing a portion of the voltage and jointly bearing the 10kV high voltage.

[0009] To address potential issues with series connection at the input stage, existing solutions employ series power unit bypass and N+1 redundancy per phase. For example, a 10kV MV-SST system has 9+1 power units connected in series, each sharing a voltage of 1000V, with a maximum voltage limit of approximately 1200V per module. When one module fails, closing its corresponding isolating switch short-circuits the module, leaving the remaining 9 modules sharing 1111V, allowing the system to continue operating normally. However, the faulty module remains within the 10kV medium-voltage line. According to medium-voltage system operating procedures, the faulty module is not de-energized or grounded, preventing its removal and replacement from the energized system. When two modules fail, the remaining 8 modules share 1250V, exceeding their operating range and rendering them unable to function properly.

[0010] Therefore, the existing MV-SST has the following disadvantages: (1) Cannot be replaced online: When the power unit fails, although it can be short-circuited by the bypass switch, the faulty module is still physically connected to the 10kV medium voltage line. According to the medium voltage power distribution safety regulations, no disassembly or replacement operation is allowed before the faulty module is completely de-energized and grounded. The whole machine must be shut down for maintenance, so online replacement is not possible.

[0011] (2) Limited redundancy: The N+1 design can only tolerate the failure of one module. When the second module fails, the remaining modules cannot support the system due to excessive voltage, and the system eventually collapses.

[0012] (3) Single output port, unable to directly support uninterrupted power supply: Existing MV-SSTs typically only have a single low-voltage DC output port with a fixed output voltage (e.g., 800V), lacking a dedicated energy storage interface, and cannot directly connect to energy storage devices such as batteries. When the mains power is interrupted, existing MV-SSTs cannot provide seamless backup power switching for downstream loads, requiring additional independent UPS or energy storage conversion devices, which increases system complexity and investment costs.

[0013] The aforementioned shortcomings mean that when existing MV-SSTs are used in AIDC data centers, a complete power outage is required for repairs in the event of a power unit failure. AIDC data centers have extremely stringent requirements for power continuity; any unplanned power outage can lead to service interruption and significant economic losses. Therefore, existing MV-SSTs are insufficient to meet the 99.999% power reliability requirement of AIDC data centers. Summary of the Invention

[0014] Purpose of the Invention: To overcome the shortcomings of the prior art, this invention provides a medium-voltage solid-state transformer and its system suitable for AIDC. By changing the topology of the power unit and other components, the power unit can be safely replaced online without interrupting the 10kV power supply. Simultaneously, it is equipped with dual low-voltage DC output ports: the first port is used for main power supply, and the second port is used for direct connection to the energy storage unit, achieving seamless switching between mains power and backup power. This invention also provides an online replacement method and system for a medium-voltage solid-state transformer suitable for AIDC.

[0015] Technical solution: According to a first aspect of the present invention, a medium-voltage solid-state transformer suitable for AIDC is provided, comprising: Multiple power units are used to convert medium-voltage AC power supplied by an external medium-voltage AC bus into DC power. Each power unit has an AC input terminal for connecting to the external medium-voltage AC bus and a DC output terminal for connecting to the output load. A mode switching device is provided, which is installed one-to-one on the connection route between the AC input terminal of each power unit and the external medium-voltage AC bus. The AC input terminal of each power unit is connected in parallel to the external medium-voltage AC bus via its respective mode switching device. The mode switching device has a pre-charge state, an on state, a discharge state, and a ground state, which are used to switch the electrical connection state between the corresponding power unit and the external medium-voltage AC bus, thereby enabling the power unit to be independently plugged in and replaced from the medium-voltage solid-state transformer.

[0016] Furthermore, including: The mode switching device is a four-position switch, corresponding to the pre-charge position, the on position, the discharge position, and the ground position, respectively. Based on the pre-charge position, the on position, the discharge position, and the ground position, a pre-charge circuit, an on circuit, a discharge circuit, and a ground circuit are formed, respectively.

[0017] Furthermore, including: The method of forming a pre-charge circuit, a connection circuit, a discharge circuit, and a grounding circuit based on the pre-charge position, the on position, the discharge position, and the grounding position respectively includes: When the AC input terminal is placed in the pre-charging position, the power unit is connected to the external medium-voltage AC bus through the first pre-charging resistor. The first pre-charging resistor is connected in series in the current path to form a pre-charging circuit. When the AC access terminal is in the ON position, the power unit is directly connected to the external medium-voltage AC bus to form a connection circuit; When the AC input terminal is set to the discharge position, the power unit is connected to ground through the discharge resistor to form a discharge circuit; When the AC input terminal is placed in the grounding position, the AC input terminal of the power unit is directly short-circuited to ground, forming a grounding loop.

[0018] Furthermore, including: The power unit further includes: The first low-voltage side port is the first DC voltage output port, which serves as the main power supply output terminal. The second low-voltage side port is the second DC voltage output port, which serves as a backup power output terminal. The first DC voltage is 800V, and the second DC voltage is 600V to 800V.

[0019] Furthermore, including: The power unit further includes a low-voltage connector, which is disposed at the rear of the power unit. The first low-voltage side port and the second low-voltage side port are respectively connected to external devices through their respective low-voltage connectors. The low-voltage connector includes at least one set of contacts, each set of contacts including a pre-charge contact and a main power contact; the pre-charge contact is connected before the main power contact when the power unit is inserted, so that the DC output bus charges the capacitor inside the power unit through the second pre-charge resistor; and is disconnected after the main power contact when the power unit is pulled out, providing a discharge path for the residual charge of the capacitor; The main power contact is connected after the pre-charge contact when the power unit is inserted, short-circuiting the second pre-charge resistor; and is disconnected before the pre-charge contact when the power unit is pulled out.

[0020] On the other hand, the present invention also provides a medium-voltage solid-state transformer system suitable for AIDC, comprising: The incoming line cabinet is located at the incoming end of the external medium-voltage AC busbar and includes a medium-voltage circuit breaker and a grounding switch. The rectifier cabinets are connected to the output terminals of the incoming line cabinets. Each rectifier cabinet is equipped with a medium-voltage solid-state transformer as described in the first aspect. The medium-voltage solid-state transformer is equipped with two or more of the power units described above. A DC output bus is used to connect the main power supply output terminal of each of the power units. An energy storage unit is used to connect to the backup power output terminal of each of the power units to provide backup power when the external medium-voltage AC bus is de-energized; A dual power supply switching module is used to switch between power supply from the medium-voltage solid-state transformer and power supply from the energy storage unit.

[0021] Thirdly, the present invention also provides an online replacement method for medium-voltage solid-state transformers suitable for AIDC. The method includes: The operating status of each power unit is detected, and a fault signal is issued when a fault is detected in a power unit; After receiving the fault signal, the fault power unit cuts off the power output, the mode switching device switches to the discharge state to release the residual charge inside the fault power unit, and switches to the ground state after the discharge is completed. The faulty power unit that is in the grounded state is disconnected from the medium-voltage solid-state transformer; The new power unit is inserted into the medium-voltage solid-state transformer, and the mode switching device switches to the pre-charging state, and the new power unit is current-limited charged through the pre-charging circuit; After pre-charging is completed, the mode switching device switches to the on state, and the new power unit is put into operation.

[0022] Furthermore, including: The step of disconnecting the faulty power unit in the grounded state from the medium-voltage solid-state transformer includes: During the unplugging process, the main power contact of the low-voltage connector disconnects first, followed by the pre-charge contact.

[0023] Furthermore, including: During the pull-out process, the main power contact of the low-voltage connector disconnects first, followed by the pre-charge contact, including: Pull the faulty power unit back from the low-voltage connector's in-place position to the pre-charge position. Since the contact end of the main power contact is shorter than the contact end of the pre-charge contact, the main power contact disconnects first, while the pre-charge contact remains in contact. The residual charge of the capacitor inside the power unit is discharged through the second pre-charge resistor. After the discharge is complete, pull the faulty power unit out completely, and the pre-charge contact then disconnects, completely isolating the faulty power unit from the DC output bus.

[0024] Furthermore, including: The insertion of the new power unit into the medium-voltage solid-state transformer includes: When inserted into the pre-charge position of the low-voltage connector, the pre-charge contact of the low-voltage connector first contacts the new power unit. After the pre-charge contact is made, the mode switching device switches to the pre-charge state and performs current-limited charging on the new power unit through the pre-charge circuit. After pre-charging is complete, the new power unit is pushed into the low-voltage connector's position, and the main power contact of the low-voltage connector makes contact. After the main power contact is made contact, the mode switching device switches to the ON state, and the new power unit is put into operation.

[0025] Furthermore, including: The method also includes: The central controller of the medium-voltage solid-state transformer sends a port configuration command to the central controller of the new power unit, configuring the first low-voltage side port as a constant voltage output mode with an output voltage of 800V, and using it as the main power supply output terminal to supply power to the DC output bus. The second low-voltage side port is configured as an adjustable output mode and connected to the energy storage unit as a backup power output terminal to realize the charging and discharging control of the energy storage unit.

[0026] Furthermore, including: The second low-voltage side port is configured as an adjustable output mode and connected to the energy storage unit as a backup power port to realize the charging and discharging control of the energy storage unit, including: When the external medium-voltage AC bus is supplying power normally, the central controller controls the second low-voltage side port to charge the energy storage unit in constant current mode or constant power mode. When the external medium-voltage AC bus is de-energized, the central controller controls the second low-voltage side port to switch to constant voltage output mode, with an output voltage of 600V to 800V. The energy storage unit supplies power to the DC output bus through the second low-voltage side port.

[0027] Fourthly, the present invention also provides an online replacement system for medium-voltage solid-state transformers suitable for AIDC, the system comprising: The signal detection module is used to detect the operating status of each power unit and to issue a fault signal when a fault is detected in a power unit. The fault unit processing module is used to cut off the power output after the fault power unit receives the fault signal, the mode switching device switches to the discharge state to release the residual charge inside the fault power unit, and switches to the ground state after the discharge is completed. The faulty power unit that is in the grounded state is disconnected from the medium-voltage solid-state transformer; The new power unit operation module is used to insert a new power unit into the medium-voltage solid-state transformer. The mode switching device switches to the pre-charging state and performs current-limited charging on the new power unit through the pre-charging circuit. After the pre-charging is completed, the mode switching device switches to the on state, and the new power unit is put into operation.

[0028] Fifthly, the present invention also provides an electronic device, comprising: a processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is in operation, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the online replacement method for a medium-voltage solid-state transformer suitable for AIDC as described in the third aspect.

[0029] In a sixth aspect, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the online replacement method for a medium-voltage solid-state transformer suitable for AIDC as described in the third aspect.

[0030] Beneficial effects: Compared with the prior art, the present invention has the following advantages: (1) Realize online replacement of power units without power outage of the whole machine: The present invention adopts power units connected in parallel to the 10kV bus on the AC side, and each power unit works independently without interference. By setting a four-position switch at the AC input terminal of the power unit, the switching device has four positions: pre-charge, on, discharge and ground. Combined with the feature that the contact end of the pre-charge contact of the low-voltage connector protrudes from the contact end of the main power contact, the electrical safety control of the power unit from connection to disconnection is realized. When a single power unit fails, it is only necessary to switch the unit to the discharge position to release the residual charge through the mode switching device, and then switch to the ground position to achieve safe isolation. Then the faulty unit is removed from the system. The remaining power units are not affected in any way. There is no need to power outage the entire solid-state transformer. This completely solves the technical problem in the prior art that the faulty module is still connected to the 10kV circuit with power even though it is bypassed, and cannot be safely disassembled and replaced.

[0031] (2) Achieving True N+X Redundancy Assurance: In this invention, N+X power units are connected in parallel, and each unit independently withstands a 10kV voltage. A faulty power unit can be completely isolated, discharged, grounded, and physically removed. During the removal and replacement process, the voltage of the remaining power units remains unchanged and unaffected, and there is no need to derating due to voltage increases. After the new unit is inserted, it starts up slowly through a pre-charge resistor, without impacting the system. The redundancy mechanism is truly effective and will not cause secondary faults due to voltage distribution imbalance. The redundancy quantity can be flexibly configured as N+1, N+2, 2N, or 2N+1, etc., according to the importance level of the load. In high-reliability scenarios such as AIDC data centers, it can ensure that the system still has complete redundancy capabilities during the replacement of any power unit failure.

[0032] (3) Dual-port output design for uninterrupted power supply: The power unit in this invention has a first low-voltage side port and a second low-voltage side port. The first port is an 800V constant voltage output for main power supply; the second port is an adjustable output of 600-800V, supporting multiple working modes such as constant voltage, constant current, and constant power, and is used to directly connect to the energy storage unit. Through the dual power switching module, when the mains power is normal, the second port charges the energy storage unit in constant current or constant power mode. When the mains power fails, the second port switches to constant voltage output mode in less than 4ms, and the energy storage unit supplies power to the DC output bus through the second port, realizing a completely seamless power switching for IT loads. Compared with the existing single-output port SST which requires additional configuration of independent UPS or energy storage conversion device, this invention simplifies the system architecture, reduces investment costs, and can directly meet the stringent requirements of AIDC data centers for power supply reliability; Therefore, in summary, through the comprehensive application of the above-mentioned technical means, this invention enables the SST system to complete the online replacement of faulty power units without power interruption, while also possessing direct energy storage connection and seamless backup power switching functions. This upgrades the SST from a single voltage conversion device into an intelligent energy router with high reliability and uninterrupted power supply capability, providing a complete solution for AIDC data centers that meets the 99.999% power availability requirement. Attached Figure Description

[0033] Figure 1 This is a schematic diagram illustrating the structural principle of a medium-voltage solid-state transformer in the prior art. Figure 2 This is a schematic diagram of the junction principle of a medium-voltage solid-state transformer suitable for AIDC provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the four-position switching switch structure described in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the pre-charge position of the low-voltage connector according to Embodiment 1 of the present invention; Figure 5This is a schematic diagram showing the placement position of the low-voltage connector according to Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the connection structure between the power unit and the rectifier cabinet back panel as described in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the application topology of the 10kV three-port energy router uninterruptible power supply system described in Embodiment 1 of the present invention in an AIDC data center. Figure 8 This is a schematic diagram of the composition of the 10kV three-port energy router uninterruptible power supply system described in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the pre-charging and discharging process of the power unit described in Embodiment 3 of the present invention; Figure 10 This is a flowchart of the online replacement method for a medium-voltage solid-state transformer suitable for AIDC as described in Embodiment 3 of the present invention; Figure 11 This is a flowchart illustrating the process of removing the faulty power unit as described in Embodiment 3 of the present invention. Figure 12 This is a flowchart of the insertion process of the new power unit as described in Embodiment 3 of the present invention; Figure 13 This is a schematic diagram of the online replacement system for a medium-voltage solid-state transformer suitable for AIDC as described in Embodiment 4 of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1: As Figure 2 As shown, this application discloses a medium-voltage solid-state transformer suitable for AIDC, comprising: Multiple power units are provided to convert medium-voltage AC power supplied by an external medium-voltage AC bus into DC power. Each power unit has an AC input terminal for connection to the external medium-voltage AC bus and a DC output terminal for connection to the output load. Figure 2 The display shows 10 corresponding power units, but this is not fixed and is set according to customer needs, but generally no less than two.

[0036] A mode switching device is provided, which is installed one-to-one on the connection route between the AC input terminal of each power unit and the external medium-voltage AC bus. The AC input terminal of each power unit is connected in parallel to the external medium-voltage AC bus via its respective mode switching device. The mode switching device has a pre-charge state, an on state, a discharge state, and a ground state, which are used to switch the electrical connection state between the corresponding power unit and the external medium-voltage AC bus, thereby enabling the power unit to be independently plugged in and replaced from the medium-voltage solid-state transformer.

[0037] In a preferred embodiment, the mode switching device is a four-position switch, corresponding to the pre-charge position, the on position, the discharge position, and the ground position, respectively. A pre-charge circuit, an on circuit, a discharge circuit, and a ground circuit are formed based on the pre-charge position, the on position, the discharge position, and the ground position, respectively.

[0038] Therefore, in conjunction with the appendix Figure 2 The structure of this solid-state transformer can be summarized as: parallel input and independent dual-port output. Specifically: 1. AC input side, i.e., 10kV busbar The 10kV three-phase AC busbar, where "3" in the diagram represents the three phase lines introduced separately, are protected by fuse FU, and are connected in parallel to the AC input terminals of each power unit U1~U10.

[0039] Each power unit is equipped with a mode switching device Q1~Q10 on its AC input side. In this embodiment, as shown... Figure 3 As shown, the mode switching device is a four-position switch with pre-charge, on, discharge, and ground positions. In the pre-charge position, the 10kV busbar charges the internal capacitor of the power unit through the pre-charge resistor R1 with current limitation; in the discharge position, the internal capacitor of the power unit releases residual charge to ground through the discharge resistor R2.

[0040] These four positions can be configured as a set of movable contacts, which are connected to the input terminal of the power unit. Driven by the operating mechanism, they can contact one of the four stationary contacts respectively, thereby switching the power unit to different working circuits.

[0041] Furthermore, in this embodiment, a pre-charge circuit, a connection circuit, a discharge circuit, and a grounding circuit are respectively formed based on the pre-charge position, the on position, the discharge position, and the grounding position, including: When the AC input terminal is placed in the pre-charging position, the power unit is connected to the external medium-voltage AC bus through the first pre-charging resistor R1. The first pre-charging resistor is connected in series in the current path to form a pre-charging circuit. When the AC access terminal is in the ON position, the power unit is directly connected to the external medium-voltage AC bus to form a connection circuit; When the AC input terminal is set to the discharge position, the power unit is connected to ground through the discharge resistor R2 to form a discharge circuit; When the AC input terminal is placed in the grounding position, the AC input terminal of the power unit is directly short-circuited to ground, forming a grounding loop.

[0042] Unlike existing medium-voltage solid-state transformer architectures, where power units are connected in series on the AC side and each module shares a portion of the voltage, in this solution, power units are connected in parallel on the AC side, and each power unit independently bears the full 10kV voltage.

[0043] 2. Power Unit Each power unit integrates an AC / DC converter, i.e., a cascaded H-bridge rectifier, responsible for rectifying 10kV AC power into DC power. The power units are connected in parallel and operate independently without interfering with each other. When a power unit fails, it can be isolated and disconnected through its corresponding mode switching device, without affecting the remaining power units.

[0044] 3. DC output side with dual-port design In this embodiment, the power unit further includes: The first low-voltage side port is the first DC voltage output port, which serves as the main power supply output terminal. The second low-voltage side port is the second DC voltage output port, which serves as a backup power output terminal. That is, each power unit outputs two independent DC power sources, and "2" in the diagram represents two DC outputs: DC Output 1: As the main power supply output terminal, it connects to the DC output bus and provides 800V constant voltage power supply to IT loads; DC Output 2: Serves as a backup power output terminal, connecting to the energy storage unit, i.e., the battery, for charge and discharge management and backup power access.

[0045] The two outputs form two independent DC buses at the system level, which respectively undertake the functions of main power supply and backup power supply.

[0046] In this embodiment, the power unit further includes a low-voltage connector, which is disposed at the rear of the power unit. The first low-voltage side port and the second low-voltage side port are respectively connected to external devices through their respective low-voltage connectors. The low-voltage connector includes at least one set of contacts, each set including a pre-charge contact and a main power contact; the pre-charge contact is connected before the main power contact when the power unit is inserted, i.e., it achieves the required charging state. Figure 4The pre-charge position allows the DC output bus to charge the capacitor inside the power unit through the second pre-charge resistor; and when the power unit is pulled out, it disconnects from the main power contact, providing a discharge path for the residual charge of the capacitor; The main power contact is connected after the pre-charge contact when the power unit is inserted, that is, to achieve the attached Figure 5 When the power unit is pulled out, the second pre-charge resistor is short-circuited in its position; and the pre-charge contact is disconnected before the power unit is pulled out.

[0047] In this embodiment, the power unit is installed on the back panel inside the rectifier cabinet, and the back panel is also equipped with connectors corresponding to the power unit. Therefore, based on the above description, as follows... Figure 6 As shown, a four-position medium-voltage switch is installed on the back panel of the rectifier cabinet, with four positions: grounding, pre-charge, connection, and discharge. The four-position medium-voltage switch has medium-voltage switch contacts for contacting the corresponding plug-in terminals at the rear of the power unit, controlling the electrical connection status between the power unit and the 10kV busbar. The rear of the power unit has plug-in terminals corresponding to the back panel, including: a medium-voltage side interface: corresponding to the medium-voltage switch contacts on the back panel, establishing a 10kV electrical connection when the power unit is pushed in; a low-voltage side 1 interface: corresponding to the first low-voltage side port; and a low-voltage side 2 interface: corresponding to the second low-voltage side port. Located at the rear of the power unit, it includes a pre-charge contact and a main power contact, with the contact end of the pre-charge contact protruding beyond the contact end of the main power contact.

[0048] Figure 6 also shows two key positions when the power unit is pushed into the backplate: Pre-charge position: The position where the power unit is shallowly pushed in. At this time, the medium-voltage switch contact is in the pre-charge position, the low-voltage connector's pre-charge contact contacts first, and the main power contact remains open, the system enters the pre-charge state. Fully inserted position: The position where the power unit is fully pushed in. At this time, the medium-voltage switch contact is in the ON position, the low-voltage connector's main power contact contacts last, and the system enters full-power operation. The timing control is achieved by controlling the physical insertion depth of the power unit to determine the contact sequence of the low-voltage connector's pre-charge contact and main power contact.

[0049] In this embodiment, in a preferred manner, the rectifier cabinet back panel is fixed to the rear of the cabinet, and the power unit is pushed in from the front of the cabinet via guide rails, gradually passing through the pre-charge position to reach the positioning position.

[0050] like Figure 7As shown, the online-swappable medium-voltage solid-state transformer (SST) system occupies a core hub position in the data center power supply architecture. Acting as an energy router, it enables intelligent scheduling and uninterrupted power supply between multiple energy inputs and load outputs. Firstly, it allows multiple input energy sources to be converted and managed internally by the SST's power electronics, achieving multi-source complementarity and seamless switching to ensure power continuity. For example: the mains power grid, connected to the SST's 10kV AC input via a 10kV cable, provides the primary power source; the photovoltaic grid, after AC / DC conversion, connects to the SST's DC bus, prioritizing the use of green energy; the wind power grid, after AC / DC conversion, connects to the SST's DC bus, complementing the photovoltaic power supply; and the generator, activated when mains power is interrupted and energy storage is insufficient, connects to the SST after AC / DC conversion, providing emergency power to the load.

[0051] Located centrally, the SST is the core device for energy routing. Its structure can be described above, and it performs the following key functions: AC / DC conversion: rectifies 10kV AC power from the mains / generator into 800V DC power; Photovoltaic / wind power integration: supports new energy DC / DC conversion and MPPT maximum power point tracking control; Energy storage interface: the second low-voltage side port is directly connected to the energy storage backup power supply, supporting bidirectional charging and discharging; Power electronic control: the built-in central controller monitors the status of each power unit in real time, realizing intelligent management functions such as current sharing control, fault detection and protection, and port configuration; Online replacement support: the power units adopt a parallel architecture and a four-position switch design, supporting online hot-swappable replacement of faulty units.

[0052] After passing through SST, the output side is for IT loads: the 800V DC output from SST is distributed to each IT cabinet, such as servers and GPU computing clusters, via the DC output bus. The DC / DC module inside the cabinet further steps down the voltage to the voltage required by the chip, such as about 1V.

[0053] Multiple IT loads are connected in parallel to the DC output bus, sharing the 800V high-voltage DC power output from SST. SST's dual power switching module can switch to the energy storage backup power supply within <4ms when the mains power is interrupted, with the IT loads completely unaware of the interruption.

[0054] In addition, the SST internal central controller in this embodiment collects operating parameters such as voltage, current, and temperature of each power unit in real time, executes logic such as current sharing control, fault detection and protection, and port configuration, and controls the switching action of power devices through drive signals. It can also communicate with the upper-level management system via Ethernet WAN or LAN to realize remote monitoring and data uploading, such as northbound transmission, fault alarms, and system scheduling, supporting intelligent operation and maintenance management of the data center.

[0055] In this embodiment Figure 7 In this configuration, energy storage backup power sources, such as high-performance lithium batteries or lead-acid battery packs, are connected to the SST via the SST's second low-voltage side port. When the mains power is normal: SST charges the energy storage unit in constant current or constant power mode; When the mains power is interrupted: the energy storage unit outputs in reverse through the second port of SST, and is boosted to 800V by DC / DC to provide uninterrupted power supply to the IT load.

[0056] Switching time: The dual power supply switching module ensures a switching time of less than 4ms, meeting the 99.999% availability requirement of AIDC data centers.

[0057] Example 2: This example also provides a medium-voltage solid-state transformer system suitable for AIDC, including: The incoming line cabinet is located at the incoming end of the external medium-voltage AC busbar and includes a medium-voltage circuit breaker and a grounding switch. The rectifier cabinets are connected to the output terminals of the incoming line cabinets. Each rectifier cabinet is equipped with a medium-voltage solid-state transformer as described in the first aspect. The medium-voltage solid-state transformer is equipped with two or more of the power units described above. A DC output bus is used to connect the main power supply output terminal of each of the power units. An energy storage unit is used to connect to the backup power output terminal of each of the power units to provide backup power when the external medium-voltage AC bus is de-energized; A dual power supply switching module is used to switch between power supply from the medium-voltage solid-state transformer and power supply from the energy storage unit.

[0058] like Figure 8 As shown, the power unit online replacement type medium voltage solid-state transformer system provided in this embodiment mainly consists of an incoming line cabinet and three rectifier cabinets, including rectifier cabinet 1, rectifier cabinet 2 and rectifier cabinet 3.

[0059] The incoming line cabinet, located at the incoming end of the external 10kV AC busbar, is the system's main input protection unit and includes at least the following: 1. Circuit breaker and grounding switch: The circuit breaker in this embodiment is used for connecting and disconnecting the 10kV incoming line, and automatically trips to protect against faults such as short circuits and overloads in the system; the grounding switch is used to ground the 10kV busbar during maintenance of the incoming line cabinet to ensure the safety of maintenance personnel.

[0060] 2. Relay protection: The relay protection device monitors the electrical quantities of the system such as voltage and current in real time. When abnormal conditions such as short circuit, overcurrent, and overvoltage occur, it issues a trip signal to cut off the fault.

[0061] 3. EMI filter, also known as electromagnetic interference filter: The EMI filter is installed at the 10kV input end to suppress electromagnetic interference generated by high-frequency switching devices inside the system from being conducted to the power grid side along the 10kV line, while preventing high-frequency interference from the power grid side from entering the system, thus meeting electromagnetic compatibility requirements.

[0062] 4. Charging Current-Limiting Resistor: The charging current-limiting resistor is connected in series between the 10kV incoming line and the power unit to limit the inrush current to the DC bus capacitor during initial system power-on or power unit insertion. The resistance value of the charging current-limiting resistor is selected based on the following criteria: under maximum inrush current conditions, it limits the charging current to the safe range allowed by the power device, typically 20% to 30% of the rated current, while ensuring that capacitor charging is completed within the pre-charging time, approximately 5 times the time constant, i.e., 60 seconds. After pre-charging is completed, the charging current-limiting resistor is short-circuited by the bypass switch and exits the working state.

[0063] 5. Discharge Current-Limiting Resistors: The three discharge current-limiting resistors corresponding to the three phases are used to release residual charge from the DC bus capacitors and internal capacitors of the power units when the power unit is disconnected or the system is shut down. The resistance value of the discharge current-limiting resistors is selected based on the following criteria: while ensuring the discharge time is not too long, the smallest possible resistance value should be selected to shorten the discharge time. At the same time, the instantaneous power withstand capability of the resistors, P = U² / R, must be greater than the instantaneous power released by the energy stored in the capacitors. After discharge, the voltage drops to a safe level, i.e., <50V.

[0064] The AC input terminals of the rectifier cabinet are connected to the output terminals of the incoming line cabinet, drawing power from the 10kV bus.

[0065] Each rectifier cabinet contains four power units: U1, U2, U3, and U-standby. U1, U2, and U3 are the operating power units, while U-standby is the backup power unit, achieving an N+1 redundancy configuration. The three rectifier cabinets together contain 12 power units, forming a complete N+X redundancy system. The AC input terminals of each power unit are connected in parallel to the 10kV bus, and the DC output terminals are connected in parallel to the DC output bus, forming a topology of parallel inputs and parallel outputs.

[0066] In this embodiment, each power unit has a rated output power of approximately 250kW, and each rectifier cabinet is configured with 3+1 power units, with a maximum output power of 840kW, i.e., 3 working units × 280kW, including overload capacity; the total output power of the 3 rectifier cabinets is 2.5MW.

[0067] Based on such Figure 8 As shown, the electrical connection path of the system is: 10kV busbar → incoming line cabinet → three parallel rectifier cabinets → power units connected in parallel in each rectifier cabinet → 800V DC output busbar → load.

[0068] In this embodiment, each power unit outputs two independent DC power supplies, namely: The first low-voltage side port: 800V constant voltage output, connected to the DC output bus, supplies power to IT loads. The second low-voltage side port: 600~800V adjustable output, connected to the energy storage unit, used for charging / discharging management and backup power access. The central controller continuously monitors the voltage, current, and other statuses of the first low-voltage side port. When a voltage drop, undervoltage, or power outage is detected at the first port, the central controller immediately determines a main power supply failure and notifies the dual power switching module. Upon receiving the command, the dual power switching module executes a first-to-last-on logic: it first issues a command to turn on the solid-state switch of the backup power circuit. At this time, the energy storage unit begins to supply power to the load through the second low-voltage side port. After confirming that the backup power circuit has been stably established, it immediately issues a command to shut down the solid-state switch of the main power supply circuit, isolating the faulty first low-voltage side port from the system. Since the action of the electronic switch is completed in microseconds, the switching time between the two power supplies is controlled within 4 milliseconds, which is much less than the power outage time that IT equipment can withstand. Therefore, the load equipment does not feel the power interruption at all. After the switching is completed, the module feeds back the result to the central controller for subsequent management.

[0069] Example 3: This example also provides an online replacement method for medium-voltage solid-state transformers suitable for AIDC, such as... Figure 10 As shown, the method includes the following steps: S1 detects the operating status of each power unit and issues a fault signal when a power unit malfunctions.

[0070] In this embodiment, the central controller detects the operating status of each power unit. When a power unit is detected to be faulty, a fault signal is issued. The judgment criteria for fault detection are divided into two cases: (1) According to the power required by the load, the theoretical value is compared with the actual measurement result. When a certain value deviates significantly, it is identified as a fault according to the judgment logic of the central controller; (2) When a certain value exceeds the allowable range of a certain component, feedback information is issued.

[0071] After receiving the fault signal, the S2 fault power unit cuts off the power output, the mode switching device switches to the discharge state, releases the residual charge inside the fault power unit, and switches to the ground state after the discharge is completed.

[0072] In this embodiment, after receiving a fault signal, the internal electronic components of the faulty power unit rapidly cut off the power output within microseconds. The mode switching device switches to the discharge state to release the residual charge inside the faulty power unit. After the discharge is complete, it switches to the ground state. After the faulty power unit cuts off the power output, the remaining power units increase their output current within a preset time and then return to the normal current.

[0073] S3 disconnects the faulty power unit, which is in the grounded state, from the medium-voltage solid-state transformer.

[0074] In this embodiment, the faulty power unit that is in a grounded state is removed from the medium-voltage solid-state transformer. During the removal process, the main power contact of the low-voltage connector disconnects first, followed by the pre-charge contact. After the faulty unit is removed, the system still maintains N+X-1 power units in operation. The redundancy is temporarily reduced by one, but it can still meet the load requirements.

[0075] S4 inserts the new power unit into the medium-voltage solid-state transformer, and the mode switching device switches to the pre-charging state, performing current-limited charging on the new power unit through the pre-charging circuit.

[0076] In this embodiment, when a new power unit is inserted into the medium-voltage solid-state transformer, the pre-charging contacts of the low-voltage connector make contact first when it is inserted into the pre-charging position. After the pre-charging contacts make contact, the mode switching device switches to the pre-charging state, and the new power unit is current-limited charged through the pre-charging circuit. The charging current is limited to a preset threshold by the charging resistor. During the pre-charging process, the capacitor voltage rises exponentially, such as... Figure 9 As shown by the curve above.

[0077] After the S5 pre-charging is completed, the mode switching device switches to the on state, and the new power unit is put into operation.

[0078] In this embodiment, after pre-charging is completed, the new power unit is pushed into its position, and the main power contact of the low-voltage connector makes contact. After the main power contact is made, the mode switching device switches to the ON state, the new power unit is put into operation, and the system returns to the N+X redundancy state. Throughout the replacement process, the DC output bus voltage fluctuation is less than ±2%, and the IT load does not perceive any power interruption.

[0079] Furthermore, in addition to the basic steps mentioned above, this method also includes the process of removing the faulty power unit and inserting the new power unit, such as... Figure 11 As shown, it also includes: Pull the faulty power unit back from the low-voltage connector's in-place position to the pre-charge position. Since the contact end of the main power contact is shorter than the contact end of the pre-charge contact, the main power contact disconnects first, while the pre-charge contact remains in contact. The residual charge of the capacitor inside the power unit is discharged through the second pre-charge resistor. After the discharge is complete, pull the faulty power unit out completely, and the pre-charge contact then disconnects, completely isolating the faulty power unit from the DC output bus.

[0080] like Figure 12As shown, when a new power unit is inserted into the pre-charge position of the low-voltage connector, the pre-charge contact of the low-voltage connector first contacts the new power unit. After the pre-charge contact is made, the mode switching device switches to the pre-charge state and performs current-limited charging on the new power unit through the pre-charge circuit. After pre-charging is complete, the new power unit is pushed into the low-voltage connector's position, and the main power contact of the low-voltage connector makes contact. After the main power contact is made contact, the mode switching device switches to the ON state, and the new power unit is put into operation.

[0081] like Figure 9 As shown, the pre-charge and discharge processes of the power unit in this embodiment have the following electrical characteristics: (a) During the pre-charging process, when the four-position switch is in the pre-charging position and the low-voltage connector is in the pre-charging position: When the power unit is inserted into the pre-charge position and the mode switch is switched to the pre-charge state, the external DC bus charges the internal capacitor of the power unit through the pre-charge resistor. The time constant of the pre-charge circuit is T≈12s, and the capacitor voltage rises exponentially from 0.

[0082] Specifically: t When the voltage is 0, the capacitor voltage is 0 and the initial charging current is at its maximum. t At time T, approximately 12 seconds later, the capacitor voltage rises to about 63.2% of its rated value, and the charging current drops to about 36.8% of its initial value. t =5T, after about 60 seconds, the capacitor voltage approaches the rated value, corresponding to the 10kV bus voltage, and the charging current approaches 0, and the pre-charging is completed; after the pre-charging is completed, the main power contact closes, the pre-charging resistor is short-circuited, and the power unit enters the full power working state.

[0083] (ii) The discharge process, i.e., when the four-position switch is in the discharge position and the low-voltage connector is in the pre-charge position: When the power unit needs to be taken out of operation, the power output is first cut off, and then the four-position switch is switched to the discharge state. The residual charge of the capacitor inside the power unit is discharged through the discharge resistor. The time constant of the discharge circuit is T≈12.1s, that is, the time constant is slightly different due to the different resistance values ​​of the discharge resistor and the charging resistor. The capacitor voltage decreases exponentially from the rated value.

[0084] Specifically, t When the voltage is 0, the capacitor voltage is at its rated value, and the initial discharge current is at its maximum. t At time T, the capacitor voltage drops to approximately 36.8% of its rated value; t When the capacitor voltage drops to near 0 at 5T, the discharge current approaches 0, and the discharge is complete.

[0085] After the discharge is complete, the four-position switch is switched to the ground state to ensure that the potential at the input terminal of the power unit is zero, thus meeting the conditions for safe disassembly.

[0086] like Figure 9 The data includes two sets of curves: the upper one is the pre-charge curve, and the lower one is the discharge curve, corresponding to the two key processes of power unit insertion and removal, respectively. The different values ​​of the charging and discharging resistors result in slight differences in the time constants: pre-charge 5T ≈ 60s, and discharge 5T ≈ 60.5s. These two curves together form the quantitative basis for the complete electrical timing sequence during online power unit replacement: pre-charge first, then placement; discharge first, then grounding.

[0087] Therefore, the discharge process (5T) is slightly longer than the pre-charge process (60.5s vs 60.0s), indicating that the time constant of the discharge circuit is slightly larger, meaning the equivalent resistance of the discharge circuit is slightly greater than the resistance of the pre-charge circuit. The difference in the values ​​of the two resistors is determined by their respective functional requirements: the pre-charge resistor needs to complete capacitor charging in a short time to shorten the insertion time, while the discharge resistor needs to limit the peak discharge current as much as possible to protect the switching devices while ensuring safe discharge.

[0088] The data in this figure are exemplary and used to illustrate the exponential variation of the pre-charge and discharge processes. They should not be construed as limiting the invention in any way. In practical applications, the time constants for pre-charge and discharge are determined by the specific resistance and capacitance values. The time constants can be adjusted by changing the resistance values ​​of the charging and discharging resistors to suit different system configurations and safety requirements.

[0089] In this embodiment, the method also includes a port configuration step, specifically: The central controller sends port configuration instructions to the new power unit, configuring the first low-voltage side port as a constant voltage output mode with an output voltage of 800V, serving as the main power supply port to supply power to the DC output bus; and configuring the second low-voltage side port as an adjustable output mode, serving as a backup power port connected to the energy storage unit to realize the charging and discharging control of the energy storage unit.

[0090] That is, the central controller of the medium-voltage solid-state transformer sends a port configuration command to the central power unit of the new power unit, configuring the first low-voltage side port as a constant voltage output mode with an output voltage of 800V, and using it as the main power supply output terminal to supply power to the DC output bus. When the external medium-voltage AC bus is supplying power normally, the central controller controls the second low-voltage side port to charge the energy storage unit in constant current mode or constant power mode. When the external medium-voltage AC bus is de-energized, the central controller controls the second low-voltage side port to switch to constant voltage output mode, with an output voltage of 600V to 800V. The energy storage unit supplies power to the DC output bus through the second low-voltage side port.

[0091] Example 4: This example also provides an online replacement system for medium-voltage solid-state transformers suitable for AIDC, such as... Figure 13 As shown, the system includes: The signal detection module is used to detect the operating status of each power unit and to issue a fault signal when a fault is detected in a power unit. The fault unit processing module is used to cut off the power output after the fault power unit receives the fault signal, the mode switching device switches to the discharge state to release the residual charge inside the fault power unit, and switches to the ground state after the discharge is completed. The faulty power unit that is in the grounded state is disconnected from the medium-voltage solid-state transformer; The new power unit operation module is used to insert a new power unit into the medium-voltage solid-state transformer. The mode switching device switches to the pre-charging state and performs current-limited charging on the new power unit through the pre-charging circuit. After the pre-charging is completed, the mode switching device switches to the on state, and the new power unit is put into operation.

[0092] The other technical features of the online replacement system for medium-voltage solid-state transformers suitable for AIDC described in this embodiment are similar to the corresponding online replacement method for medium-voltage solid-state transformers suitable for AIDC, and will not be repeated here.

[0093] This embodiment also provides an electronic device, including: a processor, a storage medium, and a bus. The storage medium stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the online replacement method for medium-voltage solid-state transformers suitable for AIDC as described in the third aspect.

[0094] Finally, this embodiment also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the online replacement method for medium-voltage solid-state transformers suitable for AIDCs as described in the third aspect.

[0095] The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0096] Through the detailed description of the above embodiments, those skilled in the art can clearly understand that each implementation can be achieved by means of software plus necessary general-purpose hardware platforms, and of course, it can also be achieved by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the prior art, can be embodied in the form of software products. These computer software products can be stored in computer-readable storage media, including read-only memory, random access memory, programmable read-only memory, erasable programmable read-only memory, programmable read-only memory, electronically erasable rewritable read-only memory, read-only optical disc or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium capable of having or storing data.

[0097] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0098] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations to the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A medium-voltage solid-state transformer suitable for AIDC, characterized in that, include: Multiple power units are used to convert medium-voltage AC power supplied by an external medium-voltage AC bus into DC power. Each power unit has an AC input terminal for connecting to the external medium-voltage AC bus and a DC output terminal for connecting to the output load. A mode switching device is provided, which is installed one-to-one on the connection route between the AC input terminal of each power unit and the external medium-voltage AC bus. The AC input terminal of each power unit is connected in parallel to the external medium-voltage AC bus via its respective mode switching device. The mode switching device has a pre-charge state, an on state, a discharge state, and a ground state, which are used to switch the electrical connection state between the corresponding power unit and the external medium-voltage AC bus, thereby enabling the power unit to be independently plugged in and replaced from the medium-voltage solid-state transformer.

2. The medium-voltage solid-state transformer suitable for AIDC according to claim 1, characterized in that, The mode switching device is a four-position switch, corresponding to the pre-charge position, the on position, the discharge position, and the ground position, respectively. Based on the pre-charge position, the on position, the discharge position, and the ground position, a pre-charge circuit, an on circuit, a discharge circuit, and a ground circuit are formed, respectively.

3. The medium-voltage solid-state transformer suitable for AIDC according to claim 2, characterized in that, The method of forming a pre-charge circuit, a connection circuit, a discharge circuit, and a grounding circuit based on the pre-charge position, the on position, the discharge position, and the grounding position respectively includes: When the AC input terminal is placed in the pre-charging position, the power unit is connected to the external medium-voltage AC bus through the first pre-charging resistor. The first pre-charging resistor is connected in series in the current path to form a pre-charging circuit. When the AC access terminal is in the ON position, the power unit is directly connected to the external medium-voltage AC bus to form a connection circuit; When the AC input terminal is set to the discharge position, the power unit is connected to ground through the discharge resistor to form a discharge circuit; When the AC input terminal is placed in the grounding position, the AC input terminal of the power unit is directly short-circuited to ground, forming a grounding loop.

4. The medium-voltage solid-state transformer suitable for AIDC according to claim 1, characterized in that, The power unit further includes: The first low-voltage side port is the first DC voltage output port, which serves as the main power supply output terminal. The second low-voltage side port is the second DC voltage output port, which serves as a backup power output terminal. The first DC voltage is 800V, and the second DC voltage is 600V to 800V.

5. The medium-voltage solid-state transformer suitable for AIDC according to claim 4, characterized in that, The power unit further includes a low-voltage connector, which is disposed at the rear of the power unit. The first low-voltage side port and the second low-voltage side port are respectively connected to external devices through their respective low-voltage connectors. The low-voltage connector includes at least one set of contacts, each set of contacts including a pre-charge contact and a main power contact; the pre-charge contact is connected before the main power contact when the power unit is inserted, so that the DC output bus charges the capacitor inside the power unit through the second pre-charge resistor; and is disconnected after the main power contact when the power unit is pulled out, providing a discharge path for the residual charge of the capacitor; The main power contact is connected after the pre-charge contact when the power unit is inserted, short-circuiting the second pre-charge resistor; and is disconnected before the pre-charge contact when the power unit is pulled out.

6. A medium-voltage solid-state transformer system suitable for AIDC, characterized in that, include: The incoming line cabinet is located at the incoming end of the external medium-voltage AC busbar and includes a medium-voltage circuit breaker and a grounding switch. A rectifier cabinet, wherein the AC input terminal of the rectifier cabinet is connected to the output terminal of the incoming line cabinet, and each rectifier cabinet is provided with a medium-voltage solid-state transformer as described in claim 4 or 5, wherein the medium-voltage solid-state transformer is provided with two or more of the power units described above. A DC output bus is used to connect the main power supply output terminal of each of the power units. An energy storage unit is used to connect to the backup power output terminal of each of the power units to provide backup power when the external medium-voltage AC bus is de-energized; A dual power supply switching module is used to switch between power supply from the medium-voltage solid-state transformer and power supply from the energy storage unit.

7. An online replacement method for a medium-voltage solid-state transformer suitable for AIDC as described in claim 6, characterized in that, The method includes: The operating status of each power unit is detected, and a fault signal is issued when a fault is detected in a power unit; After receiving the fault signal, the fault power unit cuts off the power output, the mode switching device switches to the discharge state to release the residual charge inside the fault power unit, and switches to the ground state after the discharge is completed. The faulty power unit that is in the grounded state is disconnected from the medium-voltage solid-state transformer; The new power unit is inserted into the medium-voltage solid-state transformer, and the mode switching device switches to the pre-charging state, and the new power unit is current-limited charged through the pre-charging circuit; After pre-charging is completed, the mode switching device switches to the on state, and the new power unit is put into operation.

8. The online replacement method according to claim 7, characterized in that, The step of disconnecting the faulty power unit in the grounded state from the medium-voltage solid-state transformer includes: During the unplugging process, the main power contact of the low-voltage connector disconnects first, followed by the pre-charge contact.

9. The online replacement method according to claim 8, characterized in that, During the pull-out process, the main power contact of the low-voltage connector disconnects first, followed by the pre-charge contact, including: Pull the faulty power unit back from the low-voltage connector's in-place position to the pre-charge position. Since the contact end of the main power contact is shorter than the contact end of the pre-charge contact, the main power contact disconnects first, while the pre-charge contact remains in contact. The residual charge of the capacitor inside the power unit is discharged through the second pre-charge resistor. After the discharge is complete, pull the faulty power unit out completely, and the pre-charge contact then disconnects, completely isolating the faulty power unit from the DC output bus.

10. The online replacement method according to claim 8, characterized in that, The insertion of the new power unit into the medium-voltage solid-state transformer includes: When inserted into the pre-charge position of the low-voltage connector, the pre-charge contact of the low-voltage connector first contacts the new power unit. After the pre-charge contact is made, the mode switching device switches to the pre-charge state and performs current-limited charging on the new power unit through the pre-charge circuit. After pre-charging is complete, the new power unit is pushed into the low-voltage connector's position, and the main power contact of the low-voltage connector makes contact. After the main power contact is made contact, the mode switching device switches to the ON state, and the new power unit is put into operation.

11. The online replacement method according to claim 10, characterized in that, The method also includes: The central controller of the medium-voltage solid-state transformer sends a port configuration command to the central controller of the new power unit, configuring the first low-voltage side port as a constant voltage output mode with an output voltage of 800V, and using it as the main power supply output terminal to supply power to the DC output bus. The second low-voltage side port is configured as an adjustable output mode and connected to the energy storage unit as a backup power output terminal to realize the charging and discharging control of the energy storage unit.

12. The online replacement method according to claim 11, characterized in that, The second low-voltage side port is configured as an adjustable output mode and connected to the energy storage unit as a backup power port to realize the charging and discharging control of the energy storage unit, including: When the external medium-voltage AC bus is supplying power normally, the central controller controls the second low-voltage side port to charge the energy storage unit in constant current mode or constant power mode. When the external medium-voltage AC bus is de-energized, the central controller controls the second low-voltage side port to switch to constant voltage output mode, with an output voltage of 600V to 800V. The energy storage unit supplies power to the DC output bus through the second low-voltage side port.

13. An online replacement system for medium-voltage solid-state transformers suitable for AIDC, characterized in that, The system includes: The signal detection module is used to detect the operating status of each power unit and to issue a fault signal when a fault is detected in a power unit. The fault unit processing module is used to cut off the power output after the fault power unit receives the fault signal, the mode switching device switches to the discharge state to release the residual charge inside the fault power unit, and switches to the ground state after the discharge is completed. The faulty power unit that is in the grounded state is disconnected from the medium-voltage solid-state transformer; The new power unit operation module is used to insert a new power unit into the medium-voltage solid-state transformer. The mode switching device switches to the pre-charging state and performs current-limited charging on the new power unit through the pre-charging circuit. After the pre-charging is completed, the mode switching device switches to the on state, and the new power unit is put into operation.

14. An electronic device, characterized in that, include: The device includes a processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is in operation, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the online replacement method for a medium-voltage solid-state transformer suitable for AIDC as described in any one of claims 7 to 12.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the online replacement method for a medium-voltage solid-state transformer suitable for AIDC as described in any one of claims 7 to 12.

Images