Control Method of DC Power Supply and Related Devices

Abstract

The present invention provides a control method and related device for a DC power supply. The method includes: monitoring whether the communication between the main monitoring unit and the slave monitoring unit fails; if the communication between the main monitoring unit and the slave monitoring unit does not fail, switching the working mode to the master-slave control mode; if the communication between the main monitoring unit and the slave monitoring unit fails, switching the working mode to the independent control mode, which can avoid the problem of system out-of-control caused by the communication failure between two cabinets.

Description

Technical Field

[0001] The present invention relates to the technical field of power supplies, and in particular, to a control method for a DC power supply and related devices. Background Art

[0002] The core of the power supply system architecture of a data center is an uninterruptible power supply system (UPS). The main devices that make up this system are an AC UPS (Uninterruptible Power System) or a DC HVDC (High Voltage Direct Current). To meet the power supply requirements of different reliability levels in the data center, different uninterruptible power supply architecture solutions are currently used in the industry.

[0003] To ensure the power supply reliability of a medium-voltage direct supply power source, it is currently usually considered to add a bus tie device on the low-voltage side of two rectifier cabinets to improve the reliability of the equipment. The bus tie on the low-voltage side is divided into an AC bus tie and a DC bus tie. For the DC bus tie structure, the existing control method will cause the system to get out of control when the communication between the two cabinets fails. Summary of the Invention

[0004] In view of this, the present invention provides a control method for a DC power supply and related devices, which can solve the problem that the system gets out of control due to the communication failure between two cabinets in the prior art.

[0005] In a first aspect, an embodiment of the present invention provides a control method for a DC power supply. The DC power supply includes a DC bus tie device, a main power supply device, and at least one slave power supply device. The main power supply device includes a main rectifier cabinet, a main battery module, and a main monitoring unit; the slave power supply device includes a slave rectifier cabinet, a slave battery module, and a slave monitoring unit;

[0006] The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus tie device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet;

[0007] The method is applied to the main monitoring unit and includes:

[0008] Monitoring whether the communication between the main monitoring unit and the slave monitoring unit fails;

[0009] If the communication between the main monitoring unit and the slave monitoring unit does not fail, then switch the working mode to the master-slave control mode;

[0010] In the master-slave control mode, calculate the preset voltage value for the current cycle based on the sum of the actual battery current of the master battery module and the actual battery current of the slave battery module in the current cycle; and control the output voltage of the master rectifier cabinet and the output voltage of the slave rectifier cabinet based on the preset voltage value for the current cycle.

[0011] If the communication between the master monitoring unit and the slave monitoring unit fails, switch the working mode to the independent control mode.

[0012] In the independent control mode, calculate the preset voltage value for the current cycle based on the actual battery current of the master battery module and the actual value of the bus connection current of the bus connection segment in the current cycle, and control the output voltage of the master rectifier cabinet based on the preset voltage value for the current cycle.

[0013] In a second aspect, an embodiment of the present invention provides a control device for a DC power supply. The DC power supply includes a DC bus connection device, a main power supply device, and at least one slave power supply device. The main power supply device includes a main rectifier cabinet, a main battery module, and a main monitoring unit; the slave power supply device includes a slave rectifier cabinet, a slave battery module, and a slave monitoring unit.

[0014] The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus connection device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet.

[0015] The control device of the DC power supply is applied to the main monitoring unit and includes:

[0016] A communication monitoring module for monitoring whether the communication between the main monitoring unit and the slave monitoring unit fails.

[0017] A master-slave control switching module for switching the working mode to the master-slave control mode if the communication between the main monitoring unit and the slave monitoring unit does not fail.

[0018] A master-slave control module for calculating the preset voltage value for the current cycle based on the sum of the actual battery current of the master battery module and the actual battery current of the slave battery module in the master-slave control mode; and controlling the output voltage of the master rectifier cabinet and the output voltage of the slave rectifier cabinet based on the preset voltage value for the current cycle.

[0019] An independent control switching module for switching the working mode to the independent control mode if the communication between the main monitoring unit and the slave monitoring unit fails.

[0020] An independent control module, which is used to calculate a preset voltage value for the current cycle based on the actual battery current of the main battery module and the actual value of the bus tie current of the bus tie section in the current cycle in the independent control mode, and control the output voltage of the main rectifier cabinet based on the preset voltage value of the current cycle.

[0021] In a third aspect, an embodiment of the present invention provides a control method for a DC power supply. The DC power supply includes a DC bus tie device, a main power supply device, and at least one slave power supply device. The main power supply device includes a main rectifier cabinet, a main battery module, and a main monitoring unit; the slave power supply device includes a slave rectifier cabinet, a slave battery module, and a slave monitoring unit;

[0022] The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus tie device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet;

[0023] The method is applied to the slave monitoring unit and includes:

[0024] Monitoring whether the communication between the slave monitoring unit and the main monitoring unit fails;

[0025] If the communication between the main monitoring unit and the slave monitoring unit does not fail, the working mode is switched to the master-slave control mode;

[0026] In the master-slave control mode, sending the actual battery current of the slave battery module to the main monitoring unit so that the main monitoring unit calculates a preset voltage value according to the actual battery current of the slave battery module; obtaining the preset voltage value, and controlling the output voltage of the slave rectifier cabinet based on the preset voltage value;

[0027] If the communication between the main monitoring unit and the slave monitoring unit fails, the working mode is switched to the independent control mode;

[0028] In the independent control mode, calculating the difference between the actual battery current of the slave battery module and the set value of the equalizing charge current to obtain a battery current difference; obtaining the actual value of the bus tie current of the bus tie section between the two rectifier cabinets in the current cycle, calculating a preset voltage value for the current cycle based on the battery current difference and the actual bus tie current value in the current cycle, and controlling the output voltage of the slave rectifier cabinet based on the preset voltage value of the current cycle.

[0029] Fourth aspect, an embodiment of the present invention provides a main monitoring unit, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method in any possible implementation manner of the above first aspect are implemented.

[0030] Fifth aspect, an embodiment of the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the method in any possible implementation manner of the above first aspect are implemented.

[0031] Sixth aspect, an embodiment of the present invention provides a DC power supply, which includes: a DC bus connection device, a main power supply device, and at least one slave power supply device. The main power supply device includes a main rectifier cabinet, a main battery module, and the main monitoring unit described in the above fourth aspect; the slave power supply device includes a slave rectifier cabinet, a slave battery module, and a slave monitoring unit;

[0032] The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus connection device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet.

[0033] The beneficial effects of the embodiment of the present invention compared with the prior art are as follows:

[0034] In the embodiment of the present invention, by monitoring whether the communication between the main monitoring unit and the slave monitoring unit fails; if the communication between the main monitoring unit and the slave monitoring unit does not fail, the working mode is switched to the master-slave control mode; if the communication between the main monitoring unit and the slave monitoring unit fails, the working mode is switched to the independent control mode, which can avoid the problem of system out-of-control caused by communication failure between the two cabinets. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a schematic structural diagram of a DC power supply provided by an embodiment of the present invention;

[0037] Figure 2 It is another schematic structural diagram of a DC power supply provided by an embodiment of the present invention;

[0038] Figure 3It is a schematic diagram of the communication method of the DC power supply provided by the embodiments of the present invention;

[0039] Figure 4 It is a schematic diagram of the implementation process of the control method of the DC power supply provided by the embodiments of the present invention;

[0040] Figure 5 It is a schematic diagram of the structure of the control device of the DC power supply provided by the embodiments of the present application;

[0041] Figure 6 It is a schematic diagram of the main monitoring unit provided by the embodiments of the present invention;

[0042] Figure 7 It is a control block diagram of the master-slave control mode provided by the embodiments of the present invention;

[0043] Figure 8 It is a control block diagram of the independent control mode provided by the embodiments of the present invention;

[0044] Figure 9 Schematic diagram of the structure of the DC power supply including multiple monitoring devices provided by the embodiments of the present invention. Detailed implementation manners

[0045] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will be described through specific embodiments with reference to the accompanying drawings.

[0047] Figure 1 and Figure 2 respectively show the schematic diagrams of the structures of the DC power supplies (including one slave power supply device) provided by the embodiments of the present invention. Figure 9 Shows the schematic diagram of the structure of another DC power supply (including multiple slave power supply devices) provided by the embodiments of the present invention. Refer to Figure 1 , Figure 2 and Figure 9 , the DC power supply includes a DC bus connection device, a main power supply device, and at least one slave power supply device. The main power supply device includes a main rectifier cabinet, a main battery module, and a main monitoring unit; the slave power supply device includes a slave rectifier cabinet, a slave battery module, and a slave monitoring unit;

[0048] The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus coupler device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet.

[0049] As Figure 1 , Figure 2 or Figure 9 shown, the structures of all power supply devices are the same. In practical applications, any power supply device can be used as the main power supply device, and other power supply devices can be used as slave power supply devices. Specifically, the main power supply device further includes a main phase-shifting transformer and a main power distribution unit, and the slave power supply device further includes a slave phase-shifting transformer and a slave power distribution unit. Specifically, for the main power supply device, the commercial power is connected to the high-voltage side of the main phase-shifting transformer, the low-voltage side of the main phase-shifting transformer is connected to the AC terminal of the main rectifier cabinet, the DC output terminal of the main rectifier cabinet is respectively connected to the main battery module and the main power distribution unit, and the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet are connected through the DC bus coupler device. The structural connection relationship of the slave power supply device is the same as that of the main power supply device and will not be elaborated here.

[0050] Among them, the DC bus coupler device includes a DC bus coupler device in the form of normally closed air switch and a DC bus coupler device in the form of normally closed fuse. As Figure 1 shown, the DC bus coupler device in the form of normally closed air switch includes an air switch K1, and the air switch is in the normally closed state. As Figure 2 shown, the DC bus coupler device in the form of normally closed fuse is a fuse PUSE.

[0051] In a possible embodiment, as Figure 3 shown, the DC power supply further includes a first relay; both the main monitoring unit and the slave monitoring unit include RS485 communication interfaces and CAN communication interfaces;

[0052] The main monitoring unit is communicatively connected to the main rectifier cabinet through its corresponding CAN communication interface, the slave monitoring unit is communicatively connected to the slave rectifier cabinet through its corresponding CAN communication interface, the RS485 communication interface of the main monitoring unit is connected to the RS485 communication interface of the slave monitoring unit; the CAN communication interface of the main monitoring unit is connected to the CAN communication interface of the slave monitoring unit through the first relay.

[0053] Specifically, both the main monitoring unit and the slave monitoring unit are provided with 2 RS485 communication interfaces and one CAN communication interface, as Figure 3As shown, the RS485A communication interface is used to realize the information interaction between the touch screen and the monitoring unit, enabling the touch screen to display the parameter information of this power supply device and the bus-coupler status at the same time. The CAN communication interface is used to communicate with the rectifier module, and the RS485B communication interface is used to communicate with the monitoring unit of another power supply device.

[0054] Specifically, each power supply device corresponds to a touch screen, which is used to communicate with the corresponding monitoring unit via RS485A to display the following items: the on / off status of the DC bus-coupler device, the type of the DC bus-coupler device, the breaker switch status of the normally-closed breaker-type DC bus-coupler device, the opening and closing forms of the breaker switch of the DC bus-coupler device, the cabinet number of the power supply device, and the status information of the main power supply device and the slave power supply device of the DC bus-coupler. Among them, both the opening and closing forms of the breaker switch of the DC bus-coupler device include automatic and manual.

[0055] Specifically, the data communication between two power supply devices can use RS485 communication or CAN line communication. Since using CAN line communication will connect all the communication of the rectifier modules between two rectifier cabinets together, doubling the occupancy rate of the CAN bus and posing a risk of data loss. Therefore, in this embodiment, RS485 communication is preferred. Although the communication rate of the RS485B communication interface is relatively low, considering that the control of the battery current belongs to slow-loop control, RS485 communication can meet the control requirements.

[0056] During the task of data transmission between two power supply devices by the RS485B communication interface, the main monitoring unit sends data, including: the local status, the bus voltage of the bus-coupler section, the actual battery current, the preset equalizing charge current, the load current, the total current of the rectifier modules, the number of operating rectifier modules, the battery status, the system comprehensive fault bit, the AC status, the cabinet number of the slave power supply device, and the preset voltage value, a total of 12 data. The RS485B communication uses a baud rate of 9600, the length of the transmitted data is 29 bytes (24 data bytes), and the data transmission time is 30 ms. Therefore, the sending cycle of RS485B is set to once every 50 ms.

[0057] Specifically, the first relay is a normally-closed relay; the dry contact of the RS485 communication interface of the main monitoring unit is connected to one normally-closed contact of the first relay, and the dry contact of the RS485 communication interface of the slave monitoring unit is connected to the other normally-closed contact of the first relay. When the RS485 communication interface fails, the dry contact of the RS485 communication interface disconnects, and after the first relay is powered off and closes, the CAN communication interfaces of the main and slave monitoring units establish a communication connection.

[0058] When the above DC bus-coupler device is operating normally, the main power supply device and the slave power supply device are output-connected in series, and information exchange can be carried out between the main power supply device and the slave power supply device during operation. When any one of the municipal power supplies experiences an abnormal power outage, the other can directly supply power to the load through the bus-coupler section to ensure power supply continuity.

[0059] Specifically, for the main and slave power supply devices for bus-coupling, the winding angles of their phase-shifting transformers can be the same, or they can be stagger-connected in parallel to form a 72-pulse configuration. From the perspective of usage, the output ripple of the stagger-connected parallel 72-pulse configuration is smaller than that of the 36-pulse connection with the same angle. To ensure consistency in the structural form, fuse PUSE and current Hall sensor HL are configured in both the main and slave rectifier cabinets on the bus-coupler section. The current Hall sensor is used to collect the actual value of the bus-coupler current on the bus-coupler section and send it to the monitoring unit inside the cabinet.

[0060] Specifically, both the main rectifier cabinet and the slave rectifier cabinet include multiple rectifier modules, and the multiple rectifier modules are connected in parallel for output.

[0061] See Figure 4 , which shows the implementation flowchart of the control method for the DC power supply provided by the embodiment of the present invention. This control method is applied to the main monitoring unit and is described in detail as follows:

[0062] S101: Monitor whether the communication between the main monitoring unit and the slave monitoring unit fails.

[0063] In this embodiment, the main monitoring unit and the slave monitoring unit respectively and real-time monitor whether the communication with the other party fails.

[0064] S102: If the communication between the main monitoring unit and the slave monitoring unit does not fail, switch the working mode to the master-slave control mode.

[0065] In this embodiment, if the main monitoring unit monitors that the communication with the slave monitoring unit does not fail, and the slave monitoring unit also monitors that the communication with the main monitoring unit does not fail, then both the main monitoring unit and the slave monitoring unit switch the working mode to the master-slave control mode. In the master-slave control mode, the main monitoring unit is used to uniformly control the main power supply device and the slave power supply device, and the slave monitoring unit executes the commands of the main monitoring unit.

[0066] S103: In the master-slave control mode, calculate the preset voltage value for the current cycle based on the sum of the actual battery currents of the main battery module and the slave battery module in the current cycle; and control the output voltages of the main rectifier cabinet and the slave rectifier cabinet based on the preset voltage value for the current cycle.

[0067] In the master-slave control mode, the master monitoring unit controls the operation of the master rectifier cabinet and the slave rectifier cabinet. Specifically, when the system is running normally, the master monitoring unit periodically sends the self-status data of the main power supply device to the slave monitoring unit. After receiving the status data of the master monitoring unit, the slave monitoring unit sends its own data to the master monitoring unit.

[0068] In this embodiment, the control period of a single power supply device can be 10 ms. If the main power supply device uses communication to collect the current data of the slave power supply device and then performs control, the 10-ms control period is relatively fast, which may cause data asynchronization. Considering that the battery current management belongs to slow-loop control, the control period in this embodiment can be changed to 100 ms.

[0069] Specifically, the master monitoring unit collects the actual battery current of the main battery module through a Hall current sensor. The slave monitoring unit collects the actual battery current of the slave battery module through a Hall current sensor and sends the actual battery current of the slave battery module to the master monitoring unit.

[0070] In this embodiment, Figure 7 shows the control block diagram in the master-slave control mode provided by this embodiment, as Figure 7 shown. After obtaining the actual battery current of the main battery module and the actual battery current of the slave battery module, add the actual battery current of the main battery module in the current period to the actual battery current of the slave battery module to obtain the sum of the actual battery currents I bat_fb_t , subtract the sum of the preset equalizing charging currents I bat_ret_t in the current period from the sum of the actual battery currents I bat_fb_t to obtain the difference between the two, and input the difference into the first PI controller to obtain the first voltage value; subtract the first voltage value in the current period from the preset voltage value in the previous period to obtain the preset voltage value U ret in the current period.

[0071] In a possible embodiment, after obtaining the first voltage value, the specific implementation process of determining the preset voltage value based on the first voltage value may further include:

[0072] If the actual battery current of the main battery module in the current period is greater than the preset equalizing charging current, or the actual battery current of the slave battery module in the current period is greater than the preset equalizing charging current, then use the actual battery current greater than the preset equalizing charging current as the first actual battery current, and calculate the difference between the first actual battery current and the preset equalizing charging current to obtain the single-group current difference;

[0073] Perform PI calculation on the single-group current difference to obtain the compensation voltage;

[0074] Subtract the first voltage value and the compensation voltage of the current cycle from the preset voltage value of the previous cycle respectively to obtain the preset voltage value of the current cycle.

[0075] In this embodiment, since the method provided in this embodiment regards the main battery module and the slave battery module as a whole, when the battery capacity difference between the main and slave battery modules is large, there will be a situation where the charging current of a single group of batteries is relatively high. Therefore, this embodiment can add the above-mentioned current limiting logic for a single group of batteries to avoid the situation where the charging current of a single group of batteries is relatively high.

[0076] S104: If the communication between the main monitoring unit and the slave monitoring unit fails, switch the working mode to the independent control mode.

[0077] S105: In the independent control mode, calculate the difference between the actual battery current of the main battery module and the equalizing charge current set value to obtain the battery current difference; based on the battery current difference and the actual value of the busbar connection current of the current cycle, calculate the preset voltage value of the current cycle, and control the output voltage of the main rectifier cabinet based on the preset voltage value of the current cycle.

[0078] In this embodiment, if the main monitoring unit detects that the communication with the slave monitoring unit fails, it will switch its own working mode to the independent control mode. At the same time, if the slave monitoring unit detects that the communication with the main monitoring unit fails, it will switch its own working mode to the independent control mode. In the independent control mode, the slave monitoring unit also controls the slave power supply device according to the control logic of S105. Since each monitoring unit performs independent control, there is no longer a distinction between the main and slave among the power supply devices in the independent control mode.

[0079] In a possible embodiment, the specific implementation process of S105 includes:

[0080] S201: Calculate the difference between the actual battery current and the equalizing charge current set value to obtain the battery current difference;

[0081] S202: Determine whether the actual value of the busbar connection current meets the preset conditions;

[0082] S203: If the actual value of the busbar connection current meets the preset conditions, calculate the busbar connection reference value of the current cycle based on the actual value of the busbar connection current;

[0083] S204: Based on the battery current difference and the busbar connection reference value of the current cycle, calculate the preset voltage value of the current cycle.

[0084] In a possible embodiment, the specific implementation process of S204 includes:

[0085] Input the battery current difference into the second PI controller to obtain the second voltage value of the current cycle;

[0086] Subtract the second voltage value of the current cycle from the preset voltage value of the previous cycle to obtain a preset voltage difference;

[0087] Add the preset voltage difference to the bus tie reference value to obtain the preset voltage value of the current cycle.

[0088] Specifically, Figure 8 The control block diagram in the independent control mode provided by this embodiment is shown. As Figure 8 shown, this embodiment uses the equalizing charge current set value I bat_ret minus the actual battery current I bat_fb of the current cycle to obtain the battery current difference of the current cycle, and then input the battery current difference into the second PI controller to obtain the second voltage value of the current cycle.

[0089] In this embodiment, as Figure 8 shown, the preset condition is that the absolute value of the actual bus tie current I bus_fb is greater than the preset current value I bus_H . If the actual bus tie current satisfies the preset condition, subtract the actual bus tie current I bus_ret from the bus tie current set value I bus_fb to obtain the bus tie current difference of the current cycle; input the bus tie current difference into the third PI controller to obtain the bus tie reference value of the current cycle. If the actual bus tie current does not satisfy the preset condition, set the bus tie reference value to zero.

[0090] After obtaining the bus tie reference value, subtract the second voltage value of the current cycle from the preset voltage value of the previous cycle to obtain a preset voltage difference; add the preset voltage difference to the bus tie reference value to obtain the preset voltage value U ret .

[0091] Through the above method, this embodiment can determine the working mode of the monitoring unit based on the communication situation of the two power supply devices. In the master-slave control mode, the master monitoring unit controls the master and slave power supply devices. Even if the mains power of one power supply device is cut off, the master monitoring unit can still obtain the battery current of this power supply device to achieve the control of the total battery current of the two-cabinet power supply device, thereby avoiding the problem of system out-of-control caused by the mains power failure of one circuit; in the independent control mode, when the bus tie section current does not satisfy the preset condition, the control of the bus bar current can be supplemented on the basis of the equalizing charge logic, so as to ensure that the bus tie section current is zero and avoid the problem of overcurrent of the battery current, thereby avoiding the problem of system out-of-control caused by the communication failure between the two cabinets.

[0092] In a possible embodiment, the specific implementation process of S101 includes:

[0093] If the RS485 communication between the main monitoring unit and the slave monitoring unit fails, control the first relay to switch from the open state to the closed state, so that the main monitoring unit and the slave monitoring unit are connected through CAN communication;

[0094] If a CAN communication connection is established between the main monitoring unit and the main rectifier cabinet, no CAN communication connection is established between the main monitoring unit and the slave rectifier cabinet, and no CAN communication connection is established between the main monitoring unit and the slave monitoring unit, it is determined that the communication between the main monitoring unit and the slave monitoring unit fails;

[0095] If a CAN communication connection is established between the main monitoring unit and the main rectifier cabinet, no CAN communication connection is established between the main monitoring unit and the slave monitoring unit, and a communication connection is established between the main monitoring unit and the slave rectifier cabinet, it is determined that the communication between the slave monitoring unit and the slave rectifier cabinet fails.

[0096] In this embodiment, the communication failure modes of the DC power supply include the following:

[0097] 1. The RS485 communication between the main monitoring unit and the slave monitoring unit fails.

[0098] 2. The CAN communication between the main monitoring unit and the slave monitoring unit fails.

[0099] 3. The CAN communication between the main monitoring unit and the main rectifier cabinet fails.

[0100] 4. The CAN communication between the slave monitoring unit and the slave rectifier cabinet fails.

[0101] 5. The CAN communication between the main monitoring unit and the slave rectifier cabinet fails.

[0102] 6. The CAN communication between the slave monitoring unit and the main rectifier cabinet fails.

[0103] Specifically, for the above several communication failure modes, if the RS485 communication between the main monitoring unit and the slave monitoring unit fails, control the first relay to close, so that the main monitoring unit and the slave monitoring unit are connected through CAN communication.

[0104] If a CAN communication connection has been established between the main monitoring unit and the main rectifier cabinet, the CAN communication between the main monitoring unit and the slave monitoring unit fails, and the CAN communication between the main monitoring unit and the slave rectifier cabinet fails, it is determined that the communication between the main monitoring unit and the slave monitoring unit fails, and the main monitoring unit switches to the independent control mode; at this time, if the slave monitoring unit detects that the CAN communication between the main monitoring unit and the slave monitoring unit fails, the CAN communication between the slave monitoring unit and the slave rectifier cabinet is normally connected, and the CAN communication between the slave monitoring unit and the main rectifier cabinet fails, it is determined that the communication between the main monitoring unit and the slave monitoring unit fails, and the slave monitoring unit switches its working mode to the independent control mode. If the slave rectifier cabinet has not established a communication connection with both the slave monitoring unit and the main monitoring unit, the slave rectifier cabinet operates in a monitoring failure state, and the slave rectifier cabinet controls its output voltage based on a preset monitoring failure voltage. At this time, if the main monitoring unit operates in the independent control mode, the main monitoring unit controls the output voltage of the main rectifier cabinet based on the Figure 8 control logic in it. The control logic can ensure that the voltage of the bus tie section approaches zero. Therefore, the voltage output by the main rectifier cabinet in the independent control mode is also close to the monitoring failure voltage, thus ensuring the stable operation of the entire DC power supply system.

[0105] If the main monitoring unit detects that a CAN communication connection has been established between the main monitoring unit and the main rectifier cabinet, no RS485 communication connection or CAN communication connection has been established between the main monitoring unit and the slave monitoring unit, and a communication connection has been established between the main monitoring unit and the slave rectifier cabinet. It is determined that the communication between the slave monitoring unit and the slave rectifier cabinet fails, then the main monitoring unit and the slave monitoring unit operate in the master-slave control mode. The main monitoring unit controls the operation of the main power supply device and the slave power supply device. And because the slave monitoring unit cannot communicate with the slave rectifier cabinet, after obtaining the preset voltage value, the main monitoring unit directly sends the preset voltage value to the slave rectifier cabinet through CAN communication, and other information is still received and sent by the slave monitoring unit.

[0106] If the main monitoring unit detects that no CAN communication connection has been established between the main monitoring unit and the main rectifier cabinet, while a communication connection has been established between the main monitoring unit and the slave monitoring unit, the main monitoring unit sends this information to the slave monitoring unit. The slave monitoring unit detects that no CAN communication connection has been established between the main monitoring unit and the main rectifier cabinet, and a communication connection has been established between the slave monitoring unit and the main rectifier cabinet, and a communication connection has been established between the slave monitoring unit and the slave rectifier cabinet. It is determined that the communication between the main monitoring unit and the main rectifier cabinet fails. At this time, the slave monitoring unit acts as the main monitoring unit and operates in the master-slave control mode to uniformly control the operation of the main power supply device and the slave power supply device. And because the main monitoring unit cannot communicate with the main rectifier cabinet, after obtaining the preset voltage value, the slave monitoring unit directly sends the preset voltage value to the main rectifier cabinet through CAN communication.

[0107] In a possible embodiment, the method further includes:

[0108] If the communication between the slave monitoring unit and the slave rectifier cabinet fails, the working mode is switched to the master-slave control mode, and in the master-slave control mode, the output voltage of the master rectifier cabinet and the output voltage of the slave rectifier cabinet are controlled based on the preset voltage value of the current cycle, including:

[0109] Sending the preset voltage value to the main rectifier cabinet so that the main rectifier cabinet controls the output voltage based on the preset voltage value;

[0110] The preset voltage value is sent to the slave rectifier cabinet so that the slave rectifier cabinet controls the output voltage based on the preset voltage value.

[0111] In this embodiment, when the data transmission of the master-slave monitoring unit is switched to CAN communication, the execution cycle is 10ms, and data is still sent periodically. At this time, the CAN line will connect all the rectifier modules of the two rectifier cabinets and the master-slave monitoring units together. Once switched to CAN communication, the master monitoring unit sends the preset voltage value to the slave rectifier cabinet, and other information is still sent and received by the monitoring units of each power supply device.

[0112] Since the preset voltage values ​​received by each rectifier module are sent by the main monitoring unit when CAN communication is adopted, the main monitoring unit cannot distinguish between the main rectifier cabinet and the slave rectifier cabinet. This embodiment can distinguish the rectifier modules of the two power supply devices by adding cabinet numbers. Specifically, the rectifier module of the main power supply device is not marked with the cabinet number, and the rectifier module of the slave power supply device is marked with the cabinet number. In this way, when the monitoring unit sends information such as the preset voltage value to the rectifier module, the cabinet number is marked on the sent information; the rectifier module with a cabinet number only processes the information with the same cabinet number, and the rectifier module without a cabinet number processes the information without a cabinet number. In this way, the current equalization in the cabinet is achieved.

[0113] Furthermore, the cabinet number stored inside the rectifier module can be configured on-site when the system is powered on for the first time. After a power supply device is set as a slave power supply device, the slave monitoring unit corresponding to the slave power supply device sends the cabinet number to all rectifier modules in its slave rectifier cabinet, and at the same time queries the cabinet numbers of all rectifier modules in its slave rectifier cabinet. After determining that the cabinet number is correct, the cabinet number is manually solidified. After solidification, the slave monitoring unit only processes and displays the rectifier module information with the cabinet number. The rectifier module with incorrect cabinet number is determined to be offline. The master monitoring unit only processes and displays the rectifier module information without cabinet number. In this way, the independence of the display information of the master and slave rectifier cabinets is achieved.

[0114] In a possible implementation manner of the present invention, if the monitoring unit detects that the Hall current sensor fails, the actual battery current cannot be accurately obtained. At this time, to prevent the system from being in an out-of-control state, the preset voltage value of the power supply device with the failed Hall current sensor is directly set to the monitoring failure voltage.

[0115] In an embodiment of the present application, the main monitoring unit can adjust the preset voltage value of the main rectifier cabinet every preset time period to determine whether there is current flowing through the bus tie section. If there is no current flowing through the bus tie section, it is determined that the bus tie section fuse is blown. Once the bus tie fuse is blown, the system switches to the control logic of independent equal charging of the two cabinets.

[0116] In an embodiment of the present application, if the monitoring unit of a certain power supply device fails, the normally operating monitoring unit can be used as the main monitoring unit. The main monitoring unit directly communicates with the rectifier cabinet in the voltage device with the failed monitoring unit through CAN communication to achieve the control of the power supply device with the failed monitoring unit.

[0117] In a possible embodiment, an embodiment of the present invention provides a control method for a DC power supply. The method is applied to the slave monitoring unit and includes:

[0118] Monitoring whether the communication between the slave monitoring unit and the main monitoring unit fails;

[0119] If the communication between the main monitoring unit and the slave monitoring unit does not fail, switch the working mode to the master-slave control mode;

[0120] In the master-slave control mode, send the actual battery current of the slave battery module to the main monitoring unit so that the main monitoring unit calculates the preset voltage value according to the actual battery current of the slave battery module; obtain the preset voltage value, and control the output voltage of the slave rectifier cabinet based on the preset voltage value;

[0121] If the communication between the main monitoring unit and the slave monitoring unit fails, switch the working mode to the independent control mode;

[0122] In the independent control mode, calculate the difference between the actual battery current of the slave battery module and the equal charging current set value to obtain the battery current difference; obtain the actual value of the bus tie current of the bus tie section between the two rectifier cabinets in the current cycle, and calculate the preset voltage value of the current cycle based on the battery current difference and the actual value of the bus tie current of the current cycle, and control the output voltage of the slave rectifier cabinet based on the preset voltage value of the current cycle.

[0123] Specifically, the slave monitoring unit is used to accept the unified control of the master monitoring unit in the master-slave control mode. Its main functions are data transceiver and communication monitoring. The specific control logic of the slave monitoring unit in the independent control mode is as Figure 8 shown.

[0124] Through the above solution, this embodiment can control the DC power supply to operate in different working modes under different communication conditions, thereby ensuring the stable and normal operation of the DC power supply and avoiding system out-of-control caused by communication failure.

[0125] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0126] The following is the device embodiment of the present invention. For the details not described in detail, reference can be made to the corresponding method embodiment above.

[0127] Figure 5 The structural schematic diagram of the control device of the DC power supply provided by the embodiment of the present invention is shown. The control device of the DC power supply is applied to the master monitoring unit. For the sake of convenience of description, only the parts related to the embodiment of the present invention are shown and are described in detail as follows:

[0128] As Figure 5 shown, the control device 100 of the DC power supply includes:

[0129] A communication monitoring module 110, configured to monitor whether the communication between the master monitoring unit and the slave monitoring unit fails;

[0130] A master-slave control switching module 120, configured to switch the working mode to the master-slave control mode if the communication between the master monitoring unit and the slave monitoring unit does not fail;

[0131] A master-slave control module 130, configured to calculate a preset voltage value for the current cycle based on the sum of the actual battery current of the master battery module and the actual battery current of the slave battery module in the master-slave control mode; and control the output voltage of the master rectifier cabinet and the output voltage of the slave rectifier cabinet based on the preset voltage value for the current cycle;

[0132] An independent control switching module 140, configured to switch the working mode to the independent control mode if the communication between the master monitoring unit and the slave monitoring unit fails;

[0133] An independent control module 150 is configured to, in the independent control mode, calculate a preset voltage value for the current cycle based on the actual battery current of the main battery module and the actual value of the bus tie current in the current cycle of the bus tie section, and control the output voltage of the main rectifier cabinet based on the preset voltage value for the current cycle.

[0134] In a possible embodiment, the communication monitoring module 110 includes:

[0135] If the RS485 communication between the main monitoring unit and the slave monitoring unit fails, control the first relay to switch from the open state to the closed state, so that the main monitoring unit and the slave monitoring unit are connected through CAN communication;

[0136] If a CAN communication connection is established between the main monitoring unit and the main rectifier cabinet, no CAN communication connection is established between the main monitoring unit and the slave rectifier cabinet, and no CAN communication connection is established between the main monitoring unit and the slave monitoring unit, it is determined that the communication between the main monitoring unit and the slave monitoring unit fails;

[0137] If a CAN communication connection is established between the main monitoring unit and the main rectifier cabinet, no CAN communication connection is established between the main monitoring unit and the slave monitoring unit, and a communication connection is established between the main monitoring unit and the slave rectifier cabinet, it is determined that the communication between the slave monitoring unit and the slave rectifier cabinet fails.

[0138] In a possible embodiment, the control device 100 of the DC power supply further includes a first master-slave control module, which is configured to:

[0139] If the communication between the slave monitoring unit and the slave rectifier cabinet fails, switch the working mode to the master-slave control mode, and in the master-slave control mode, the control of the output voltage of the main rectifier cabinet and the output voltage of the slave rectifier cabinet based on the preset voltage value for the current cycle includes:

[0140] Send the preset voltage value to the main rectifier cabinet, so that the main rectifier cabinet controls the output voltage based on the preset voltage value;

[0141] Send the preset voltage value to the slave rectifier cabinet, so that the slave rectifier cabinet controls the output voltage based on the preset voltage value.

[0142] In a possible embodiment, the independent control module 150 includes:

[0143] A battery current difference calculation unit, configured to calculate the difference between the actual battery current and the equalizing charge current setting value to obtain a battery current difference;

[0144] A condition judgment unit for judging whether the actual value of the bus-tie current meets a preset condition;

[0145] A bus-tie reference value calculation unit for calculating the bus-tie reference value of the current cycle based on the actual value of the bus-tie current if the actual value of the bus-tie current meets the preset condition;

[0146] A preset voltage value calculation unit for calculating the preset voltage value of the current cycle based on the battery current difference and the bus-tie reference value of the current cycle.

[0147] In a possible embodiment, the preset voltage value calculation unit includes:

[0148] Inputting the battery current difference into a second PI controller to obtain the second voltage value of the current cycle;

[0149] Subtracting the second voltage value of the current cycle from the preset voltage value of the previous cycle to obtain a preset voltage difference;

[0150] Adding the preset voltage difference to the bus-tie reference value to obtain the preset voltage value of the current cycle.

[0151] The control device of the DC power supply provided in this embodiment can be used to execute the embodiments of the control method of the DC power supply above. The implementation principle and technical effects are similar, and will not be elaborated here in this embodiment.

[0152] Figure 6 It is a schematic diagram of a monitoring unit provided by an embodiment of the present invention. As Figure 6 shown, the main monitoring unit 6 of this embodiment includes: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60. When the processor 60 executes the computer program 62, the steps in the above embodiments of the control method of each DC power supply are implemented, such as Figure 4 the steps S101 to S105 shown. Alternatively, when the processor 60 executes the computer program 62, the functions of each module / unit in the above device embodiments are implemented, such as Figure 5 the functions of the modules 110 to 150 shown.

[0153] Exemplarily, the computer program 62 can be divided into one or more modules / units. The one or more modules / units are stored in the memory 61 and executed by the processor 60 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and these instruction segments are used to describe the execution process of the computer program 62 in the main monitoring unit 6.

[0154] The main monitoring unit 6 may be a computing device such as a desktop computer, a notebook, a palm computer, or a cloud server. The main monitoring unit 6 may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art can understand that Figure 6 These are merely examples of the main monitoring unit 6 and do not constitute a limitation on the main monitoring unit 6. It may include more or fewer components than those shown in the figure, or combine certain components, or have different components. For example, the monitoring unit may further include input / output devices, network access devices, a bus, etc.

[0155] The so-called processor 60 may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0156] The memory 61 may be an internal storage unit of the main monitoring unit 6, such as the hard disk or memory of the main monitoring unit 6. The memory 61 may also be an external storage device of the main monitoring unit 6, such as a plug-in hard disk equipped on the main monitoring unit 6, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. Further, the memory 61 may also include both the internal storage unit and the external storage device of the main monitoring unit 6. The memory 61 is used to store the computer program and other programs and data required by the monitoring unit. The memory 61 may also be used to temporarily store data that has been output or is to be output.

[0157] Those skilled in the art can clearly understand that, for the convenience and conciseness of description, only the above-mentioned division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of this application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0158] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0159] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0160] In the embodiments provided by the present invention, it should be understood that the disclosed device / monitoring unit and method can be implemented in other ways. For example, the device / monitoring unit embodiments described above are only illustrative. For example, the division of the above-mentioned module or unit is only a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in electrical, mechanical or other forms.

[0161] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0162] In addition, in each embodiment of the present invention, each functional unit can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0163] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, all or part of the processes in the above-described embodiment methods of the present invention can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-described embodiments of the control method for each DC power supply can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0164] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A control method for a DC power supply, characterized in that, The DC power supply includes a DC bus coupling device, a main power supply device, and at least one slave power supply device. The main power supply device includes a main rectifier cabinet, a main battery module, and a main monitoring unit; the slave power supply device includes a slave rectifier cabinet, a slave battery module, and a slave monitoring unit; The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus coupling device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet; The method is applied to the main monitoring unit and includes: Monitoring whether the communication between the main monitoring unit and the slave monitoring unit fails; If the communication between the main monitoring unit and the slave monitoring unit does not fail, switch the working mode to the master-slave control mode; In the master-slave control mode, calculate the preset voltage value for the current cycle based on the sum of the actual battery currents of the main battery module and the slave battery module in the current cycle; and control the output voltages of the main rectifier cabinet and the slave rectifier cabinet based on the preset voltage value for the current cycle; If the communication between the main monitoring unit and the slave monitoring unit fails, switch the working mode to the independent control mode; In the independent control mode, calculate the preset voltage value for the current cycle based on the actual battery current of the main battery module and the actual value of the bus coupling current of the bus coupling section in the current cycle, and control the output voltage of the main rectifier cabinet based on the preset voltage value for the current cycle; The calculating the preset voltage value for the current cycle based on the actual battery current of the main battery module and the actual value of the bus coupling current of the bus coupling section in the independent control mode includes: Calculate the difference between the actual battery current and the equalizing charge current setting value to obtain the battery current difference; Judge whether the actual value of the bus coupling current meets the preset condition; If the actual value of the bus coupling current meets the preset condition, calculate the bus coupling reference value for the current cycle based on the actual value of the bus coupling current; if the actual value of the bus coupling current does not meet the preset condition, set the bus coupling reference value to zero; Calculate the preset voltage value for the current cycle based on the battery current difference and the bus coupling reference value for the current cycle.

2. The control method of the DC power supply according to claim 1, wherein The DC power supply further includes a first relay; both the main monitoring unit and the slave monitoring unit include RS485 communication interfaces and CAN communication interfaces; The main monitoring unit is communicatively connected to the main rectifier cabinet through its corresponding CAN communication interface, the slave monitoring unit is communicatively connected to the slave rectifier cabinet through its corresponding CAN communication interface, and the RS485 communication interface of the main monitoring unit is connected to the RS485 communication interface of the slave monitoring unit; the CAN communication interface of the main monitoring unit is connected to the CAN communication interface of the slave monitoring unit through the first relay; The monitoring whether the communication between the main monitoring unit and the slave monitoring unit fails includes: If the RS485 communication between the main monitoring unit and the slave monitoring unit fails, control the first relay to switch from the off state to the on state, so that the main monitoring unit and the slave monitoring unit are connected through CAN communication; If a CAN communication connection is established between the main monitoring unit and the main rectifier cabinet, no CAN communication connection is established between the main monitoring unit and the slave rectifier cabinet, and no CAN communication connection is established between the main monitoring unit and the slave monitoring unit, it is determined that the communication between the main monitoring unit and the slave monitoring unit fails; If a CAN communication connection is established between the main monitoring unit and the main rectifier cabinet, no CAN communication connection is established between the main monitoring unit and the slave monitoring unit, and a communication connection is established between the main monitoring unit and the slave rectifier cabinet, it is determined that the communication between the slave monitoring unit and the slave rectifier cabinet fails.

3. The control method of the DC power supply according to claim 2, characterized in that, The method further includes: If the communication between the slave monitoring unit and the slave rectifier cabinet fails, switch the working mode to the master-slave control mode, and in the master-slave control mode, controlling the output voltage of the main rectifier cabinet and the output voltage of the slave rectifier cabinet based on the preset voltage value of the current cycle includes: Sending the preset voltage value to the main rectifier cabinet, so that the main rectifier cabinet controls the output voltage based on the preset voltage value; Sending the preset voltage value to the slave rectifier cabinet, so that the slave rectifier cabinet controls the output voltage based on the preset voltage value.

4. The control method of the DC power supply according to claim 1, characterized in that, Calculating the preset voltage value of the current cycle based on the battery current difference and the bus tie reference value of the current cycle includes: Inputting the battery current difference into a second PI controller to obtain the second voltage value of the current cycle; Subtracting the second voltage value of the current cycle from the preset voltage value of the previous cycle to obtain a preset voltage difference; Adding the preset voltage difference and the bus tie reference value to obtain the preset voltage value of the current cycle.

5. A control method for a DC power supply, characterized in that, The DC power supply includes a DC bus tie device, a main power supply device and at least one slave power supply device. The main power supply device includes a main rectifier cabinet, a main battery module and a main monitoring unit; the slave power supply device includes a slave rectifier cabinet, a slave battery module and a slave monitoring unit; The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus tie device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet; The method is applied to the slave monitoring unit and includes: Monitoring whether the communication between the slave monitoring unit and the main monitoring unit fails; If the communication between the main monitoring unit and the slave monitoring unit does not fail, switch the working mode to the master-slave control mode; In the master-slave control mode, sending the actual battery current of the slave battery module to the main monitoring unit, so that the main monitoring unit calculates the preset voltage value according to the actual battery current of the slave battery module; obtaining the preset voltage value, and controlling the output voltage of the slave rectifier cabinet based on the preset voltage value; If the communication between the main monitoring unit and the slave monitoring unit fails, the working mode is switched to the independent control mode; In the independent control mode, calculate the difference between the actual battery current of the slave battery module and the equalizing charge current set value to obtain the battery current difference; obtain the actual value of the bus tie current of the bus tie section between the two rectifier cabinets in the current cycle, and calculate the preset voltage value of the current cycle based on the battery current difference and the actual value of the bus tie current of the current cycle, and control the output voltage of the slave rectifier cabinet based on the preset voltage value of the current cycle; The obtaining the actual value of the bus tie current of the bus tie section between the two rectifier cabinets in the current cycle, and calculating the preset voltage value of the current cycle based on the battery current difference and the actual value of the bus tie current of the current cycle includes: Judge whether the actual value of the bus tie current meets the preset conditions; If the actual value of the bus tie current meets the preset conditions, calculate the bus tie reference value of the current cycle based on the actual value of the bus tie current; if the actual value of the bus tie current does not meet the preset conditions, set the bus tie reference value to zero; Calculate the preset voltage value of the current cycle based on the battery current difference and the bus tie reference value of the current cycle.

6. A control device for a DC power supply, characterized in that, The DC power supply includes a DC bus tie device, a main power supply device and at least one slave power supply device, the main power supply device includes a main rectifier cabinet, a main battery module and a main monitoring unit; the slave power supply device includes a slave rectifier cabinet, a slave battery module and a slave monitoring unit; The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus tie device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet; The control device of the DC power supply is applied to the main monitoring unit and includes: A communication monitoring module for monitoring whether the communication between the main monitoring unit and the slave monitoring unit fails; A master-slave control switching module for switching the working mode to the master-slave control mode if the communication between the main monitoring unit and the slave monitoring unit does not fail; A master-slave control module for calculating the preset voltage value of the current cycle based on the sum of the actual battery currents of the main battery module and the slave battery module in the current cycle in the master-slave control mode; and controlling the output voltages of the main rectifier cabinet and the slave rectifier cabinet based on the preset voltage value of the current cycle; An independent control switching module for switching the working mode to the independent control mode if the communication between the main monitoring unit and the slave monitoring unit fails; An independent control module for calculating the preset voltage value of the current cycle based on the actual battery current of the main battery module and the actual value of the bus tie current of the bus tie section in the independent control mode, and controlling the output voltage of the main rectifier cabinet based on the preset voltage value of the current cycle; The independent control module is specifically used for: In the independent control mode, calculate the difference between the actual battery current and the equalizing charge current set value to obtain the battery current difference; Judge whether the actual value of the bus tie current meets the preset conditions; If the actual value of the bus tie current meets the preset conditions, calculate the bus tie reference value for the current period based on the actual value of the bus tie current; if the actual value of the bus tie current does not meet the preset conditions, set the bus tie reference value to zero; Calculate the preset voltage value for the current period based on the battery current difference and the bus tie reference value for the current period.

7. A main monitoring unit, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 4.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the steps of the method according to any one of claims 1 to 4 above are implemented.

9. A DC power supply, characterized in that, Including: A DC bus tie device, a main power supply device, and at least one slave power supply device. The main power supply device includes a main rectifier cabinet, a main battery module, and a main monitoring unit according to claim 7; the slave power supply device includes a slave rectifier cabinet, a slave battery module, and a slave monitoring unit; The DC output terminal of the main rectifier cabinet is connected to the main battery module; the DC output terminal of the slave rectifier cabinet is connected to the slave battery module, and the DC bus tie device is connected between the DC output terminals of the main rectifier cabinet and the slave rectifier cabinet.

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