Power supply device

Abstract

A power supply device is used for reducing cable cost and electric energy transmission loss of the power supply device. The power supply device comprises at least one rectification module, a DC bus and a controller. The input end of each rectification module is connected with an alternating current power supply, the first output end of each rectification module is connected with the first end of the direct current bus, the second output end of each rectification module is connected with the second end of the direct current bus, and the intermediate node of each rectification module is connected with the intermediate node of the direct current bus; each rectification module comprises a plurality of rectifiers which are connected in series, the first output end of each rectification module is the high-level end of the input end of the first rectifier in the plurality of internal rectifiers, and the second output end of each rectification module is the low-level output end of the last rectifier in the plurality of internal rectifiers; the direct-current bus is connected with a load; the controller is connected with each rectification module, and is used for controlling each rectification module to carry out rectification processing on the electric energy of the AC power supply and output the electric energy to the DC bus.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and more particularly to a power supply device. Background Technology

[0002] Three-wire HVDC systems are widely used in power supply scenarios such as data centers and high-tech applications due to their high efficiency and low loss. The rectifier in a three-wire HVDC system converts AC power from an external AC source into bus voltage and supplies power to downstream equipment via a DC bus with positive and negative busbars. For high-power supply scenarios, multiple rectifiers are required, and each rectifier needs at least two cables connected to the DC bus, increasing the cable cost and transmission loss of the three-wire HVDC system. Utility Model Content

[0003] The purpose of this application is to provide a power supply device for improving and reducing transmission losses and cable count in DC systems.

[0004] This application provides a power supply device that can serve as a three-phase high-voltage DC system to supply power to multiple devices that use DC power. The power supply device may include at least one rectifier module, a DC bus, and a controller.

[0005] Each rectifier module has its input terminal connected to an AC power source, its first output terminal connected to the first terminal of a DC bus, its second output terminal connected to the second terminal of the DC bus, and its intermediate node connected to the intermediate node of the DC bus. Each rectifier module includes multiple rectifiers connected in series. The first output terminal of each rectifier module is the high-level input terminal of the first rectifier among the multiple internal rectifiers, and the second output terminal of each rectifier module is the low-level output terminal of the last rectifier among the multiple internal rectifiers. The DC bus is used to connect to a load. The controller is connected to each rectifier module and controls each rectifier module to rectify the AC power and output it to the DC bus.

[0006] Using the above method, when the rectifier module rectifies the power of the external AC power supply, each rectifier connected in series can receive a portion of the power for conversion, and multiple rectifiers connected in series only need to be configured with three power transmission cables. Thus, while achieving high power supply, it can improve conversion efficiency and reduce the number of cables.

[0007] In one possible design, the power supply device also includes an energy storage device and a voltage regulation circuit.

[0008] In this design, the first terminal of the voltage regulating circuit is connected to the DC bus, and the second terminal is connected to the energy storage device. The voltage regulating circuit converts the voltage of the DC bus into the charging voltage of the energy storage device and charges the device, or converts the voltage of the energy storage device into the rated voltage of the DC bus and supplies power to the DC bus. With this design, the configured energy storage device can provide temporary power when the external AC power supply to the power supply device fails, thereby improving the power supply stability of the power supply device.

[0009] In one possible design, the controller is connected to the voltage regulating circuit. The controller is also configured to control the voltage regulating circuit to discharge the energy storage device when the voltage of the AC power supply is detected to be less than a first preset threshold, and to control the voltage regulating circuit to charge the energy storage device when the voltage of the AC power supply is detected to be greater than the first preset threshold and the remaining capacity of the energy storage device is less than a second preset threshold.

[0010] In one possible design, the controller is further configured to: control the voltage regulation circuit to discharge the energy storage device when it detects that the output power of the rectifier module in the power supply device is less than the power supply power of the load. With this design, when the power demand of the load connected to the downstream increases, causing the output power of the rectifier module connected to the AC power supply to be insufficient to meet the load's power requirements, the energy storage device can be controlled to perform power compensation, ensuring the normal operation of the load.

[0011] In one possible design, the controller is further configured to: control the voltage regulating circuit to discharge the energy storage device during a first time period, and control the voltage regulating circuit to charge the energy storage device during a second time period. With this design, the first time period corresponds to the peak electricity consumption period of the power grid, and the second time period corresponds to the off-peak electricity consumption period. This allows the energy storage device to supply power during peak power consumption periods and charge during off-peak periods, which helps alleviate the power grid's supply pressure.

[0012] In one possible design, the power supply device further includes a protection module, and the controller is connected to the protection module to control the activation and deactivation of the protection module according to the operating electrical parameters of the power supply device.

[0013] In one possible design, the protection module includes an insulation protection circuit, which includes an insulated branch connected to each phase line of the DC bus. The controller is also configured to trigger a fault alarm when the voltage at an intermediate node of the DC bus is detected to be greater than a third preset threshold.

[0014] In one possible design, the controller is further configured to: when the power supply device includes multiple rectifier modules, control the current of each rectifier module to be within a preset range. With this design, due to manufacturing limitations, when multiple rectifier modules operate in parallel, the current on each rectifier module may not be the same. This could lead to some rectifier modules exceeding their maximum allowable current, causing device failure. The controller can control the current on each rectifier module to be the same or similar, ensuring that each rectifier module receives the same power and preventing overload of any single rectifier module.

[0015] In one possible design, the power supply device further includes a switch connected in series with each rectifier module, and the controller is further configured to: when it is determined that the current or voltage of the target rectifier module is greater than a fourth preset threshold, control the switch connected to the target rectifier module to disconnect. With the above design, when a single rectifier module fails, the switch connected to the faulty rectifier module can be controlled to disconnect, thereby isolating the fault source and preventing the fault range from expanding.

[0016] In one possible design, the controller is also used to receive touch signals from the display panel and control the opening and closing of each switch according to the touch signals. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the structure of a power supply device provided in an embodiment of this application. Figure 1 ;

[0019] Figure 2 This is a schematic diagram of the structure of a rectifier module provided in an embodiment of this application;

[0020] Figure 3 A schematic diagram of the structure of a power supply device provided in an embodiment of this application. Figure 2 ;

[0021] Figure 4 This is a schematic diagram of the structure of a monitoring system provided in an embodiment of this application. Detailed Implementation

[0022] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0023] The terminology used in the implementation section of this application is only for explaining specific embodiments of this application and is not intended to limit this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0024] The following explanations of some terms used in the embodiments of this application are provided to facilitate understanding by those skilled in the art.

[0025] (1) The terms “first”, “second”, etc., used in the embodiments of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in a sequence other than those illustrated or described herein.

[0026] (2) In the embodiments of this application, “multiple” refers to two or more, and other quantifiers are similar.

[0027] (3) In the embodiments of this application, "connection" can be understood as an electrical connection or a communication connection. An electrical connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components, such as the connection between A and B. Alternatively, it can be a direct connection between A and C, and a direct connection between C and B, with A and B connected through C. A communication connection between two electrical components is a wireless connection between the two electrical components, that is, an electromagnetic connection between the two electrical components.

[0028] (4) The switching devices in this application embodiment can be one or more of various types of switching transistors, such as relays, metal oxide semiconductor field effect transistors (MOSFETs), bipolar junction transistors (BJTs), insulated gate bipolar transistors (IGBTs), silicon carbide (SiC) transistors, and silicon controlled rectifiers (SCRs). These will not be listed individually in this application embodiment. The packaging of each switching transistor can be a single-transistor package or a multi-transistor package; this application embodiment does not impose any restrictions on this. Each switching transistor can include a first terminal, a second terminal, and a control terminal. The control terminal can control the switching transistor to turn on or off according to the received PWM signal. When the switching transistor is on, current can be transmitted between the first terminal and the second terminal; when the switching transistor is off, current cannot be transmitted between the first terminal and the second terminal. Taking a MOSFET as an example, the control terminal of the switching transistor is the gate, the first terminal of the switching transistor can be the source, and the second terminal can be the drain, or the first terminal can be the drain and the second terminal can be the source.

[0029] The application scenarios of the power supply device in the embodiments of this application will be described in detail below with reference to the accompanying drawings. The power supply device provided in the embodiments of this application can be applied to DC power supply scenarios, that is, the power supply device can supply power to multiple electrical devices using DC power supply, or it can supply power to multiple electrical devices using AC power supply through an inverter.

[0030] See Figure 1 The diagram shown is a structural schematic of the power supply device provided in an embodiment of this application. Figure 1 As shown, the power supply device includes at least one rectifier module, a DC bus, and a controller.

[0031] It should be understood that, Figure 1 The power supply device shown is merely an example; power supply devices can have more than that. Figure 1 The diagram shows additional components, such as relays connected to the AC power supply or to the load, which can be configured in the power supply unit to control the relays connected to the AC power source or the load. When the power supply unit or the external AC power source fails, these relays can be controlled to disconnect, thereby cutting off the fault source and preventing the fault from spreading. Figure 1 The various components shown can be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and / or application-specific integrated circuits.

[0032] Specifically, the input terminal of each rectifier module is connected to the AC power supply, the first output terminal of each rectifier module is connected to the first terminal of the DC bus, the second output terminal of each rectifier module is connected to the second terminal of the DC bus, and the intermediate node of each rectifier module is connected to the intermediate node of the DC bus. The DC bus is used to connect to the load. A controller is connected to each rectifier module to control each rectifier module to rectify the AC power supply and output it to the DC bus. Each rectifier module includes multiple rectifiers connected in series. The first output terminal of each rectifier module is the high-level input terminal of the first rectifier among the multiple internal rectifiers, and the second output terminal of each rectifier module is the low-level output terminal of the last rectifier among the multiple internal rectifiers.

[0033] It should be noted that, Figure 1 The description takes a power supply device equipped with multiple rectifier modules and a DC bus consisting of bus capacitor C1 and bus capacitor C2 as an example. In actual applications, the power supply device may be equipped with only one rectifier module, and this application does not make specific limitations on this.

[0034] The power supply device provided in this application embodiment has one or more rectifier modules internally, and each rectifier module is connected between an external AC power source and a DC bus with positive and negative buses. Each rectifier module includes multiple rectifiers connected in series. When each rectifier module is working, each rectifier inside can receive a portion of the power output from the AC power source and output the received power after rectification. Since the rectifiers inside the rectifier module are connected in series, the conversion power of a single rectifier module is the sum of the conversion power of the multiple rectifiers inside. Furthermore, the multiple rectifiers in a single rectifier module only require three cables connected to the DC bus to achieve power transmission. Therefore, while meeting the demand for high-power power supply, the number of cables inside the power supply device can be reduced, which is beneficial for reducing cable costs and power transmission losses.

[0035] In practical applications, the power supply unit can be equipped with a housing, with the rectifier module, DC bus and controller all inside the housing. The housing is equipped with external interfaces for connecting to AC power and for connecting to loads. AC power and loads can be connected to the power supply unit through the corresponding external interfaces.

[0036] When using the power supply device provided in this application embodiment to supply power to a load, multiple electrical devices using DC power can be directly connected to the DC bus and obtain the electrical energy required for operation from the DC bus. Multiple electrical devices using AC power can be connected to the DC bus through an inverter, which can convert the voltage on the DC bus into AC power to supply power to the multiple electrical devices connected to the back end.

[0037] In practical applications, multiple rectifiers within each rectifier module are connected in series. The intermediate node of the series-connected rectifiers is connected to the intermediate node of the DC bus. Taking the DC bus as an example, which includes a +400V positive bus, a -400V negative bus, and a neutral line N, half of the rectifiers connected between the first output terminal and the intermediate node in the rectifier module are powered by the positive bus, and the other half of the rectifiers connected between the intermediate node and the second output terminal are powered by the negative bus.

[0038] It should be noted that the rectifier can adopt a circuit topology with the above-mentioned functions that is commonly used in the industry, such as H-bridge rectifier circuit and Vienna circuit. Of course, the rectifier can also be implemented using integrated chips and peripheral circuits, which is not limited here.

[0039] See Figure 2 The diagram shown illustrates one possible power supply structure when a single rectifier module comprises two rectifiers connected in series. Figure 2 As shown, the rectifier module includes rectifiers U1 and U2 connected in series. The first output terminal of rectifier U1 is connected to the positive bus BUS+, and the second output terminal of rectifier U1 is connected to the neutral line N. The first output terminal of rectifier U2 is connected to the negative bus BUS-, and the second output terminal of rectifier U2 is connected to the neutral line N.

[0040] use Figure 2 When the rectifier module structure shown is powered by the DC bus, since the input terminals of rectifiers U1 and U2 are connected in series, if the device models of rectifiers U1 and U2 are the same and the drive signals are also the same, under ideal conditions, the voltage received by rectifiers U1 and U2 is half of the AC power output. That is, rectifiers U1 and U2 receive half of the AC power and perform conversion processing respectively. Rectifier U1 uses the processed electrical energy to power the positive bus BUS+ connected to the back end, and rectifier U2 uses the processed electrical energy to power the negative bus BUS- connected to the back end.

[0041] It should be noted that, Figure 2 The rectifier module shown is only an example. In actual applications, each rectifier module may include more than two rectifiers. For example, a single rectifier module may include six rectifiers connected in series. This application does not impose any further limitations here.

[0042] In practical applications, the rectifier in the rectifier module is half composed of a switching transistor and an energy storage inductor. The operation of the rectifier can be controlled by turning the switching transistor on and off. The controller of the aforementioned switching transistor can be connected to the controller inside the power supply device. The controller can drive the switching transistor to turn on and off by sending a drive signal of the corresponding level to the connected switching device, thereby controlling the operation of the rectifier.

[0043] In some implementations, since the DC bus is powered by an external AC power source, the power supply cannot supply power to the downstream loads when the AC power source fails. To improve the power supply stability of the power supply device, see [link to relevant documentation]. Figure 3 As shown, the power supply unit also includes an energy storage device and a voltage regulating circuit connected between the energy storage device and the DC bus.

[0044] The voltage regulating circuit has its first terminal connected to the DC bus and its second terminal connected to the energy storage device. This circuit can be a bidirectional power transmission device, performing both charging and discharging operations on the energy storage device. When charging the energy storage device, the voltage regulating circuit converts the DC bus voltage to the charging voltage of the energy storage device. When discharging the energy storage device, the voltage regulating circuit converts the energy storage device voltage to the rated voltage of the DC bus and supplies power to the DC bus.

[0045] In practical applications, the voltage regulating circuit can charge the energy storage device using a portion of the AC power supply when the external AC power supply is normal, and supply power to the DC bus using the energy stored in the energy storage device when the AC power supply fails, until the AC power supply failure is resolved, thereby improving the power supply stability of the power supply device. The operation of the aforementioned voltage regulating circuit can be implemented by a controller. The controller can control the voltage regulating circuit to discharge the energy storage device when it detects that the AC power supply voltage is less than a first preset threshold, and control the voltage regulating circuit to charge the energy storage device when it detects that the AC power supply voltage is greater than the first preset threshold and the remaining capacity of the energy storage device is less than a second preset threshold. The first preset threshold can be set according to the normal operating range of the AC power supply. For example, if the normal operating range of the AC power supply is [370V, 390V], the first preset threshold can be set to 360V. Of course, other values ​​can also be used for the first preset threshold, which are not limited in this application.

[0046] In some implementations, the controller can also detect the power supply of the load. When the output power of the rectifier module in the power supply device is less than the power supply control of the load, it indicates that the power output of the AC power supply cannot meet the power supply requirements of the load. In order to ensure the normal operation of the load, the voltage regulation circuit can be controlled to discharge the energy storage device to meet the power supply requirements of the load.

[0047] In one implementation, the external power source connected to the power supply device is typically the power grid, which connects to multiple electrical devices awaiting power. During peak power consumption periods, if the power supply device continues to draw power from the grid, it may cause voltage fluctuations in the grid, affecting its normal operation. To alleviate the pressure on the power grid, the controller can control the voltage regulation circuit to discharge the energy storage device during the first time period and then control the voltage regulation circuit to charge the energy storage device during the second time period.

[0048] The first and second time periods are the peak and off-peak electricity consumption periods of the power grid, respectively. The first and second time periods can be determined by instructions issued by the power grid or by monitoring the electrical parameters operating on the power grid; this application does not impose further limitations on these determinations.

[0049] The above describes the scenario where a power supply device is configured with a single rectifier module. If the conversion power of a single rectifier module cannot meet the power requirements, multiple rectifier modules can be configured in the power supply device. These multiple rectifier modules are connected in parallel. In practical applications, due to manufacturing and other reasons, the current amplitude flowing through each rectifier module may be different, which may cause the current in some rectifier modules to exceed the normal operating current. In order to ensure the normal operation of the power supply device, the power supply control can adjust the current value of each rectifier module by controlling the conduction sequence of the switching transistors in the rectifier module and configuring a variable resistor, so that the current of each rectifier module is within a preset range.

[0050] It should be noted that configuring a variable resistor or adjusting the conduction timing of the switching transistor is only one way to share current among multiple rectifier modules. This application can also use other methods to achieve current sharing among multiple rectifier modules, which will not be described in detail here.

[0051] In some implementations, since multiple rectifiers in a rectifier module are connected in series, the entire rectifier module will fail if one rectifier in the module fails. When the power supply unit is equipped with multiple parallel rectifier modules, a corresponding switch can be configured for each rectifier module to ensure that the other rectifier modules can supply power to the DC bus normally. Each switch can be connected in series with a corresponding switch. When the controller detects a faulty target rectifier module, it can control the switch connected to the target rectifier module to disconnect, thereby disconnecting the faulty rectifier module from the normal rectifier modules and preventing the fault range from expanding.

[0052] In practical applications, the fault status of a rectifier module can be determined by detecting its electrical parameters during operation. For example, if the current of a rectifier module exceeds a fourth preset threshold, that module can be identified as the faulty target rectifier module. The fourth preset threshold can be set based on the maximum allowable current of the rectifier module during operation. For instance, if the maximum allowable current during normal operation is 50A, the fourth preset threshold can be set to 51A.

[0053] Specifically, rectifier module faults include, but are not limited to, overcurrent faults, short-circuit faults, and overvoltage faults. Power supply units are generally equipped with a monitoring system, which can consist of multiple connected detection devices used to monitor the operating status of each rectifier module. For example, the monitoring system may include voltage and current detectors connected to each rectifier module. These detectors can detect the voltage and current of each rectifier module and feed the detected values ​​back to the controller. When the controller detects that the rectifier's current or voltage value exceeds the corresponding normal operating range, it can determine that a rectifier module has failed and control the switch connected to that module to disconnect it. This disconnects the faulty rectifier module from the main circuit and other normal rectifier modules, isolating the fault source and preventing the fault from spreading further. The normal operating range corresponding to the current and voltage values ​​can be set according to the power supply unit's connection scenario and the internal configuration of the rectifier module, which will not be discussed further in this application.

[0054] In one example, when the load connected to the back end decreases, the output power of the power supply exceeds the power demanded by the load. If all rectifier modules are still controlled to operate and supply power to the load connected to the back end of the DC bus, it will result in wasted energy. To avoid wasting energy, operators can also turn off some rectifier modules via a touch display. When the controller receives a touch signal for the operation of the rectifier modules, it can control the corresponding switch to disconnect and stop the operation of some rectifier modules.

[0055] In practical applications, in addition to the fault protection of the rectifier module mentioned above, the controller can also perform other protections to achieve the safety protection of the main circuit.

[0056] In one example, the monitoring system also includes a current detector, a leakage current detector, and a voltage detector configured in the main circuit. The power supply unit is also configured with switching devices connected to the AC power supply and switching devices connected to the load. When the controller detects that the current value in the main circuit exceeds the corresponding normal operating range, it can control the switching devices connected to the AC power supply and the switching devices connected to the load to ensure the safety of other devices connected to the faulty device.

[0057] See Figure 4The diagram illustrates a possible structure of a monitoring system. The current detector module includes a first current detector for detecting the main circuit current and a second current detector corresponding to each rectifier module. Each second current detector can detect the current on its corresponding rectifier module. The voltage detector module includes a first voltage detector for detecting the main circuit voltage and a second voltage detector module corresponding to each phase line in the DC bus. Each second voltage detector can detect the voltage on its corresponding rectifier module. Both the current and voltage detector modules transmit the detected values ​​to the controller for fault diagnosis.

[0058] In practical applications, since power supply devices are generally equipped with cabinets, multiple devices in the power supply device are located inside the cabinet, and the cabinet is equipped with a power interface for connecting to AC power and a load interface for connecting to the load. When the power supply device needs to be tested for insulation, the leakage current detector can be connected to the power interface of the cabinet at one end and grounded at the other end to provide leakage current protection for the cabinet.

[0059] It should be noted that, Figure 4 The monitoring system structure shown is for illustrative purposes only. In actual applications, the number and location of detectors in the current and voltage detector modules can be configured according to the location and number of detection points in the power supply unit. Additionally, the leakage current detector detects leakage current in the power supply unit by detecting leakage current in the cabinet. Other commonly used leakage current detection methods can also be used, and the type and installation location of the leakage current detector should be configured according to the leakage current detection method. This application does not impose further limitations on this.

[0060] In one example, the power supply unit is also configured with an insulated branch connected to each phase line of the DC bus. When the controller detects that the voltage at the intermediate node of the DC bus is greater than a third preset threshold, it triggers a fault alarm to prompt the operator to perform fault repair.

[0061] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A power supply device, characterized in that, include: At least one rectifier module, DC bus, and controller; The input terminal of each rectifier module is connected to the AC power supply, the first output terminal of each rectifier module is connected to the first terminal of the DC bus, the second output terminal of each rectifier module is connected to the second terminal of the DC bus, and the intermediate node of each rectifier module is connected to the intermediate node of the DC bus. Each rectifier module includes multiple rectifiers connected in series. The first output terminal of each rectifier module is the high-level input terminal of the first rectifier among the multiple rectifiers, and the second output terminal of each rectifier module is the low-level output terminal of the last rectifier among the multiple rectifiers. The DC bus is used to connect to the load; The controller is connected to each rectifier module and is used to control each rectifier module to rectify the electrical energy of the AC power supply and output it to the DC bus.

2. The apparatus according to claim 1, characterized in that, The power supply device also includes an energy storage device and a voltage regulation circuit; The first terminal of the voltage regulating circuit is connected to the DC bus, and the second terminal of the voltage regulating circuit is connected to the energy storage device. It is used to convert the voltage of the DC bus into the charging voltage of the energy storage device and charge the energy storage device, or to convert the voltage of the energy storage device into the rated voltage of the DC bus and supply power to the DC bus.

3. The apparatus according to claim 2, characterized in that, The controller is connected to the voltage regulating circuit. The controller is also used to control the voltage regulating circuit to discharge the energy storage device when the voltage of the AC power supply is detected to be less than a first preset threshold, and to control the voltage regulating circuit to charge the energy storage device when the voltage of the AC power supply is detected to be greater than the first preset threshold and the remaining capacity of the energy storage device is less than a second preset threshold.

4. The apparatus according to claim 2, characterized in that, The controller is also configured to: when it is detected that the output power of the rectifier module in the power supply device is less than the power supply power of the load, control the voltage regulation circuit to discharge the energy storage device.

5. The apparatus according to claim 2, characterized in that, The controller is also configured to: control the voltage regulating circuit to discharge the energy storage device during a first time period, and control the voltage regulating circuit to charge the energy storage device during a second time period.

6. The apparatus according to claim 1 or 2, characterized in that, The power supply device also includes a protection module, and the controller is connected to the protection module to control the activation and deactivation of the protection module according to the operating electrical parameters of the power supply device.

7. The apparatus according to claim 6, characterized in that, The protection module includes an insulation protection circuit, which includes an insulated branch connected to each phase line of the DC bus. The controller is also used to trigger a fault alarm when the voltage at an intermediate node of the DC bus is detected to be greater than a third preset threshold.

8. The apparatus according to claim 1, characterized in that, The controller is also used to: when the power supply device includes multiple rectifier modules, control the current of each rectifier module to be within a preset range.

9. The apparatus according to claim 1, characterized in that, The power supply device also includes a switch connected in series with each rectifier module, and the controller is further configured to: when it is determined that the current or voltage of the target rectifier module is greater than a fourth preset threshold, control the switch connected to the target rectifier module to disconnect.

10. The apparatus according to claim 9, characterized in that, The controller is also used to receive touch signals from the display panel and control the opening and closing of each switch according to the touch signals.

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