CN110661333A

CN110661333A - Direct-current power supply system and monitoring method thereof

Info

Publication number: CN110661333A
Application number: CN201911016751.1A
Authority: CN
Inventors: 张立强; 王潇; 季志鹏; 杨睿; 刘兰军; 金久才
Original assignee: Ocean University of China
Current assignee: Ocean University of China
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2020-01-07
Anticipated expiration: 2039-10-24
Also published as: CN110661333B

Abstract

The invention relates to a direct current power supply system and a monitoring method thereof, wherein the system comprises an external energy storage battery pack, an upper computer, a switching power supply unit, a power supply management unit and a voltage stabilizing and current divider unit; the power management unit is connected with the switching power supply unit, the external energy storage battery pack, the upper computer and the voltage stabilizing and current divider unit; the power management unit comprises a constant voltage current-limiting DC-DC unit, an auxiliary power supply unit and a main control unit; the voltage stabilizing and current divider unit comprises a DC-DC voltage stabilizing unit and a current divider unit; the switch power supply unit, the power supply management unit and the voltage stabilizing and current divider unit are all provided with detection modules so as to monitor the state of each unit; meanwhile, each detection module is communicated with the main control unit so as to carry out fault diagnosis and isolation. The direct-current power supply system is an extensible multi-voltage-level output system, adopts hardware modularization and software hierarchical design, has fault diagnosis and isolation functions, and improves the reliability and safety of the whole power supply system.

Description

Direct-current power supply system and monitoring method thereof

Technical Field

The invention belongs to the technical field of direct-current power supplies, and particularly relates to a direct-current power supply system supporting fault diagnosis and a monitoring method thereof.

Background

In marine instrument equipment, the load form is various, and in order to guarantee long-time stable operation, generally must have power management system or direct current supply unit. A common form today is an energy storage battery combined DC-DC converter architecture. The energy storage battery is generally a non-rechargeable lithium battery or a rechargeable lithium ion battery.

The non-rechargeable lithium primary battery is generally used in the fields of Argo buoys, underwater gliders and the like, the voltage level required by instrument circuits is obtained through corresponding DC-DC converters after the batteries are grouped, the whole circuit is powered, and the total power supply power is small. The lithium primary battery is discarded along with the equipment after the discharge is finished or is discarded after being recycled to the shore or the mother ship. The lithium primary battery has poor economical efficiency, and even causes certain environmental pollution due to improper disposal. Since the lithium primary battery is disposable, such power supply systems do not include monitoring of the battery, the converter or the load, and therefore accurate information of the operating state, the health state or the fault state of the power supply system itself cannot be obtained.

The lithium ion battery capable of being charged for multiple times has the advantages of high energy density, high-rate discharge and repeated charge and discharge, and is mainly used in the fields of electric propulsion of various unmanned ships, ROVs, AUVs and the like at present. The first type of direct current power supply system is similar to the first type of direct current power supply system, and after the batteries are grouped, the voltage required by a load is obtained through a DC-DC converter, so that a direct current power supply output with medium power can be provided. Such dc power systems are generally equipped with a lithium ion battery pack protection, balancing, and remaining capacity (SOC) estimation circuit, which only passively monitors the state of the lithium ion battery, and lacks monitoring of the state of each converter and load in the entire power system. Therefore, such systems also cannot obtain detailed operating state and fault state information of each component in the whole power supply system. The second type of direct-current power supply system is used for a direct-current power supply system of a large ship, a water surface or an underwater platform, is generally a direct-current micro-grid, and is very similar to a land direct-current micro-grid in structure. The direct-current power supply system is generally provided with a perfect relay protection and monitoring system, but the direct-current power supply system is generally a finished product, so that the functions of the direct-current power supply system are difficult to freely increase and decrease according to requirements of users, and the direct-current power supply system is difficult to directly use in common marine instrument equipment due to complex structure and large volume.

In addition, the working environment of marine instrument equipment is severe, and the power supply system and various loads of the marine instrument equipment are easy to break down. If the power failure can not be timely positioned and isolated, the reliability of the whole instrument and equipment can be affected. Therefore, it is necessary to research a dc power supply system with a fault diagnosis function, which can monitor each component, an energy storage battery, and various loads in a power supply system in real time, locate a fault according to monitored data, and actively isolate the fault.

Disclosure of Invention

The invention provides a direct current power supply system and a monitoring method thereof on the basis of the defects, and by adopting the system, all parts, energy storage batteries and various loads in the power supply system can be monitored in real time, fault location is carried out according to monitoring data, and fault isolation is actively carried out.

In order to achieve the aim, the invention provides a direct current power supply system which comprises a hardware part, wherein the hardware part comprises an external energy storage battery pack, an upper computer, a switching power supply unit, a power supply management unit and a voltage stabilizing and current divider unit;

the switching power supply unit comprises a switching power supply module and a switching power supply detection module, wherein the switching power supply module is used for converting alternating current input power supply voltage into direct current input bus voltage and supplying power to a direct current power supply system; the switching power supply detection module is connected with the switching power supply module and used for monitoring the state of the switching power supply;

the external energy storage battery pack is connected to a direct current input bus and used for stabilizing the voltage of the direct current input bus and supplying power to a direct current power supply system when the switch power supply module fails;

the power supply management unit is connected with the switching power supply unit, the external energy storage battery pack, the upper computer and the voltage stabilizing and current divider unit; the power management unit comprises a constant-voltage current-limiting DC-DC unit, an auxiliary power supply unit and a main control unit;

the constant-voltage current-limiting DC-DC unit comprises a constant-voltage current-limiting DC-DC conversion module and a constant-voltage current-limiting detection module; the switching power supply module is connected to a direct current input bus through the constant voltage current limiting DC-DC conversion module; the constant voltage current limiting detection module is connected with the constant voltage current limiting DC-DC conversion module and is used for monitoring the state of the constant voltage current limiting DC-DC conversion module;

the auxiliary power supply unit comprises an auxiliary power supply module and an auxiliary power supply detection module, wherein the auxiliary power supply module is connected to the output end of the constant-voltage current-limiting DC-DC conversion module and is used for supplying power to the power supply management unit and the voltage stabilizing and current divider unit when the switching power supply module and an external energy storage battery pack are in failure; the auxiliary power supply detection module is connected with the auxiliary power supply module and used for monitoring the state of the auxiliary power supply module;

the main control unit is connected with the switching power supply detection module, the constant-voltage current-limiting detection module, the auxiliary power supply detection module and the voltage-stabilizing and current-dividing unit and is used for receiving state information collected by the detection modules of the switching power supply unit, the power supply management unit and the voltage-stabilizing and current-dividing unit and carrying out fault diagnosis and isolation;

the voltage stabilizing and current dividing unit comprises a DC-DC voltage stabilizing unit and a current dividing unit; the DC-DC voltage stabilizing unit comprises at least one voltage-grade voltage stabilizing DC-DC conversion module, and each voltage stabilizing DC-DC conversion module is connected with the power supply management unit and used for outputting at least one voltage-grade direct-current voltage stabilizing power supply; the current divider unit comprises a wide voltage output current divider and at least one voltage-stabilizing output current divider; the wide-voltage output current divider is connected with the power management unit and an external wide-voltage load through a direct-current input bus; each voltage-stabilizing DC-DC conversion module is connected to an external load through a voltage-stabilizing output shunt.

Preferably, the switching power supply detection module comprises a first relay, a first relay driving module, a first voltage and current measurement module and a first single chip microcomputer module; the direct current output end of the switching power supply module is connected to the first relay; the first relay driving module is connected with the first singlechip module and the first relay and is used for controlling the on-off of the first relay; the first voltage and current measuring module is connected to the direct current output end of the switching power supply module and used for collecting output voltage and current information of the switching power supply module and transmitting the output voltage and current information to the first single chip microcomputer module.

Preferably, the constant voltage current-limiting detection module comprises a second voltage and current measurement module, a current control module and a second single chip microcomputer module; the constant-voltage current-limiting DC-DC conversion module is connected with the output end of the switching power supply module through the first relay; the second voltage and current measuring module is connected with the output end of the constant voltage current-limiting DC-DC conversion module and is used for collecting output voltage and current information of the constant voltage current-limiting DC-DC conversion module and transmitting the output voltage and current information to the second single chip microcomputer module; the current control module is connected with the second single chip microcomputer module and the constant-voltage current-limiting DC-DC conversion module and is used for controlling the current limiting value of the constant-voltage current-limiting DC-DC conversion module.

Preferably, the auxiliary power supply module comprises a first DC-DC conversion module, a UPS module, a second DC-DC conversion module, an internal energy storage battery pack, and a black start switch;

the first DC-DC conversion module is connected with a direct current input bus, the output end of the first DC-DC conversion module is connected with the input end of the UPS module, the internal energy storage battery pack is connected with the input end of the UPS module, the output end of the UPS module is connected with the black start switch, the output end of the black start switch is connected with the second DC-DC conversion module, and the second DC-DC conversion module is used for outputting auxiliary power supply voltages with different voltage levels and supplying power to the power management unit and the voltage stabilizing and current divider unit;

the auxiliary power supply detection module comprises a third voltage and current measurement module, a fourth voltage and current measurement module, a fifth voltage and current measurement module and a third single chip microcomputer module;

the third voltage and current measuring module is connected with the output end of the first DC-DC conversion module and is used for collecting output voltage and current information of the first DC-DC conversion module and transmitting the output voltage and current information to the third single chip microcomputer module; the fourth voltage and current measuring module is connected with the output end of the internal energy storage battery pack and used for acquiring output voltage and current information of the internal energy storage battery pack and transmitting the output voltage and current information to the third single chip microcomputer module; and the fifth voltage and current measuring module is connected with the output end of the black start switch and used for acquiring the output voltage and current information of the black start switch and transmitting the output voltage and current information to the third single chip microcomputer module.

Preferably, the power management unit further comprises a battery pack balancing and protecting unit; the battery pack balancing and protecting unit comprises a protection balancing module, a second relay driving module, a fourth single chip microcomputer module, a sixth voltage and current measuring module and a seventh voltage and current measuring module;

the protection balancing module is connected to a middle tap of the external energy storage battery pack and is used for detecting the voltage of the single battery and protecting and balancing; the protection balancing module is connected to the direct current input bus through the second relay; the second relay driving module is connected with the second relay and the fourth singlechip module and is used for controlling the on-off of the second relay;

the sixth voltage and current measuring module is connected with the protection balancing module and used for collecting output voltage and current information of the protection balancing module and transmitting the output voltage and current information to the fourth single chip microcomputer module;

and the seventh voltage and current measuring module is connected with a middle tap of the external energy storage battery pack and used for collecting the voltage of the middle tap of the external energy storage battery pack and transmitting the voltage to the fourth single chip microcomputer module.

Preferably, the main control unit comprises an FPGA main control module, a CAN bus module and a serial port drive module;

the CAN bus module comprises a first path of CAN bus and a second path of CAN bus; the first single chip microcomputer module, the second single chip microcomputer module, the third single chip microcomputer module and the fourth single chip microcomputer module are connected with the FPGA main control module through the first path of CAN bus; the FPGA main control module is connected with an environment monitoring module through the second CAN bus, and the environment monitoring module comprises a plurality of sensors for monitoring external environment information; the upper computer is connected to the FPGA main control module through the serial port driving module.

Preferably, the wide-voltage output current divider comprises a fifth single chip microcomputer module, a sixth single chip microcomputer module, a plurality of eighth voltage and current measuring modules, an MOS transistor driving circuit, a double MOS transistor, a fuse, an auxiliary power supply interface and a load interface;

each load output connected with the direct current input bus is subjected to switch control through double MOS tubes, and each double MOS tube is connected with the direct current input bus and is connected to an external wide voltage load through a fuse and a load interface; the MOS tube driving circuit is connected with the sixth singlechip module and each double MOS tube and is used for controlling the on-off state of each double MOS tube; the output end of each fuse is connected with an eighth voltage and current measuring module respectively, and the eighth voltage and current measuring module is used for acquiring voltage and current information of an external wide voltage load output by each load and transmitting the voltage and current information to the fifth single chip microcomputer module; an auxiliary power supply interface of the wide-voltage output current divider is connected to an auxiliary power supply output interface of the power supply management unit; the wide-voltage output current divider is connected with the FPGA main control module through the first CAN bus.

Preferably, the voltage stabilization output current divider comprises a seventh single chip microcomputer module, an eighth single chip microcomputer module, a ninth single chip microcomputer module, a plurality of ninth voltage and current measurement modules, a tenth voltage and current measurement module, a plurality of eleventh voltage and current measurement modules, an MOS transistor driving circuit, a double MOS transistor, a fuse, an ideal diode, an auxiliary power supply interface and a load interface;

each voltage-stabilizing DC-DC conversion module is connected with an ideal diode module in series to form a direct-current voltage-stabilizing bus, and the output end of each voltage-stabilizing DC-DC conversion module is connected with a ninth voltage and current measuring module respectively and used for collecting voltage and current information output by each voltage-stabilizing DC-DC conversion module and transmitting the voltage and current information to a seventh single chip microcomputer module to monitor the state of each voltage-stabilizing DC-DC conversion module; the tenth voltage and current measuring module is connected with the direct current voltage stabilizing bus and used for collecting voltage and current information of the direct current voltage stabilizing bus and transmitting the voltage and current information to the seventh single chip microcomputer module;

each load output connected with the direct-current voltage-stabilizing bus is subjected to on-off control through double MOS (metal oxide semiconductor) tubes, each double MOS tube is connected with the direct-current voltage-stabilizing bus, and then is connected with an external load through a fuse and a load interface; the MOS tube driving circuit is connected with the eighth singlechip module and each double MOS tube and is used for controlling the on-off state of each double MOS tube; the output end of each fuse is connected with one eleventh voltage and current measuring module respectively, and the eleventh voltage and current measuring module is used for collecting voltage and current information of external loads output by each load, monitoring the state of each external load and transmitting the state of each external load to the ninth singlechip module; the auxiliary power supply interface of each voltage stabilizing output current divider is connected to the auxiliary power supply output interface of the power supply management unit; each voltage stabilizing output current divider is connected with the FPGA main control module through a first CAN bus.

Preferably, the direct current power supply system further comprises a software part, wherein the software part comprises a bottom layer single chip microcomputer software module, a middle layer CAN bus communication module and a top layer FPGA software module;

the single chip microcomputer software module runs in each single chip microcomputer module of the switching power supply unit, the power supply management unit and the voltage stabilizing and current divider unit, and is used for reading voltage and current measured values in each voltage and current measuring module and performing primary fault diagnosis and fault isolation according to the voltage and current measured values in each voltage and current measuring module;

the CAN bus communication module runs among the singlechip modules of the switching power supply unit, the power supply management unit and the voltage stabilizing and current divider unit and the FPGA main control module and is used for communication between each singlechip module and the FPGA main control module;

the FPGA software module runs in the FPGA main control module and is used for polling and diagnosing the state information acquired by the detection modules of the switching power supply unit, the power supply management unit, the voltage stabilizing and current divider unit and the information of the environment monitoring module, grading faults according to the fault diagnosis information and isolating the fault modules.

The invention also provides a monitoring method of the direct-current power supply system, which comprises the following steps:

the method comprises the following steps that a black start switch is closed, the system is electrified and works, and an FPGA main control module polls state information of all parts of an external energy storage battery pack, a switch power supply unit, a power supply management unit and a voltage stabilizing and current divider unit;

if the output voltage and the output current of the switching power supply module are detected not to reach the normal value within the given time, recording the fault of the switching power supply and keeping the first relay disconnected; if the voltage of the external energy storage battery pack or the voltage of a certain monomer is detected to be abnormal, recording the fault of the external energy storage battery pack and immediately disconnecting the second relay;

if the switching power supply module is normal and the battery pack is abnormal, starting the constant-voltage current-limiting DC-DC conversion module, and simultaneously setting a current-limiting value as a maximum value; if the switching power supply is normal and the battery pack is normal, determining a current limiting value according to the voltage of the external energy storage battery pack, and then starting the constant-voltage current-limiting DC-DC conversion module;

determining the working mode of the direct-current power supply system according to the states of the switching power supply module and the external energy storage battery pack;

if the voltage of the direct current input bus is detected to be normal, the double MOS tubes of the wide voltage output current divider are started, and the direct current wide voltage power supply voltage is output; meanwhile, whether the direct-current stabilized voltage bus is normal or not is judged, if the direct-current stabilized voltage bus is normal, a double MOS (metal oxide semiconductor) tube of the stabilized voltage output current divider is started, and the voltage of the direct-current stabilized voltage supply is output;

after the system is powered on, the FPGA main control module continuously monitors voltage and current information of each component of an external energy storage battery pack, a switch power supply unit, a power supply management unit, a voltage stabilizing and current divider unit of the direct-current power supply system, judges a working mode and carries out fault diagnosis and isolation.

Compared with the prior art, the invention has the advantages and positive effects that:

the invention provides a direct current power supply system for system fault diagnosis, which adopts hardware modularization and software hierarchical design, has fault diagnosis and isolation functions, and improves the reliability and safety of the whole power supply system.

(1) The main circuit of the power supply system is provided with a switching power supply module, a constant-voltage current-limiting DC-DC conversion module, a voltage-stabilizing DC-DC conversion module, an auxiliary power supply module and an external energy storage battery pack, and the output voltage grade can be expanded or changed only by adding or replacing the DC-DC voltage-stabilizing power supply module as required without modifying the structure of a power supply management part.

(2) The power supply system adopts the internal unified CAN bus communication and hierarchical software design, the single chip microcomputer measurement and control at the bottom layer and the FPGA main control at the upper layer are layered, and the middle part is connected through the unified CAN bus communication. The software hierarchical design method reduces the difficulty of software development and communication protocol development in the system expansion or modification process.

(3) The power supply system monitors input and output voltages and currents of the modules, judges the types of faults possibly occurring in the modules by using a certain fault diagnosis algorithm, positions the faults, and isolates the fault modules by using the relays, the module enable switches and the like. Meanwhile, the voltage and the current of an external load are monitored in real time, and when the load equipment has faults such as power failure, short circuit and the like, the fault equipment is turned off in time through the MOS tube, so that the safety of a power supply system is guaranteed.

(4) The power supply system is also provided with an auxiliary power supply, so that the single chip microcomputer module, the voltage and current measuring module, the MOS drive and other monitoring modules can normally operate under the condition that the main circuit is powered off, and the main circuit can be detected, diagnosed and controlled. Due to the existence of the auxiliary power supply, the whole power supply system can be directly started and monitored through the black start switch to complete the fault diagnosis function.

Drawings

FIG. 1 is an overall block diagram of a DC power supply system of the present invention;

FIG. 2 is a detailed block diagram of the switching power supply unit and the power management unit of the DC power supply system according to the present invention;

FIG. 3 is a functional diagram of a switching power supply unit and a power management unit of the DC power supply system according to the present invention;

FIG. 4 is a circuit diagram of a voltage and current measuring module of the DC power supply system according to the present invention;

FIG. 5 is a schematic diagram of a relay drive circuit of the DC power supply system of the present invention;

FIG. 6 is a circuit diagram of a current control module of the DC power system according to the present invention;

FIG. 7 is a diagram of a CAN bus circuit configuration of the DC power supply system of the present invention;

FIG. 8 is a detailed block diagram of the voltage regulator and shunt unit of the DC power supply system of the present invention;

FIG. 9 is a structural diagram of a dual MOS transistor and a driving circuit thereof of the DC power supply system according to the present invention;

FIG. 10 is a software layer layout of the DC power system of the present invention;

FIG. 11 is a software flow diagram of a single-chip microcomputer module of the DC power supply system of the present invention;

FIG. 12 is a flow chart of FPGA module software for the DC power system of the present invention;

fig. 13 is a flow chart of power-on monitoring of the dc power system according to the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "comprises" and "comprising," and any variations thereof, in the description and claims of this invention and the above-described drawings are intended to cover non-exclusive inclusions. For example, a process, method, or system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus. Furthermore, the terms "first," "second," and "third," etc. are used to distinguish between different objects and are not used to describe a particular order.

The invention provides a multi-voltage-level direct-current power supply system supporting fault diagnosis, which is oriented to the direct-current power supply application scene of marine instruments and equipment. The direct-current power supply system has the functions of fault diagnosis and isolation, the faults of each power electronic module, each battery pack and each load are preliminarily diagnosed by monitoring the voltage, the current and partial temperature data of each power electronic module, each battery pack and each load in the direct-current power supply system, and fault parts are isolated according to the fault conditions, so that the reliability and the safety of the whole power supply system are improved.

The dc power supply system provided by the embodiment includes a hardware portion and a software portion.

Firstly, hardware design:

in the present embodiment, a hardware portion is designed in a modularized manner, and referring to fig. 1 to 9, fig. 1 is an overall block diagram of a dc power supply system, where the hardware portion includes an external energy storage battery pack, an upper computer, a switching power supply unit, a power supply management unit, and a voltage stabilizing and current divider unit.

Specifically, the method comprises the following steps:

(1) as for the switching power supply unit, referring to fig. 2, the switching power supply unit specifically includes a switching power supply module and a switching power supply detection module; the switch power supply detection module is connected with the switch power supply module and used for monitoring state information of the switch module, and comprises a first relay, a first relay driving module, a first voltage and current measurement module and a first single chip microcomputer module. The direct current output end of the switch power supply module is connected to the first relay, and the switch power supply module is used for converting alternating current input power supply voltage into direct current input bus voltage and supplying power for a direct current power supply system. The first voltage and current measuring module is connected to the direct current output end of the switch power supply module and used for collecting output voltage and current information of the switch power supply module and transmitting the output voltage and current information to the first single chip microcomputer module to monitor the output voltage and current of the switch power supply module in real time. The first relay driving module is connected with the first relay and the first single chip microcomputer module and used for controlling the on-off of the first relay.

In the embodiment, the switching power supply module adopts a wide-range alternating current input and 48V direct current output model, the input alternating voltage range is 96-264 Vac, the output maximum current is 42A, the output maximum power is 2016W, and the nominal efficiency is 92%. Current measurement adopts current detection resistance to combine the special fortune of current detection to put among the first voltage current measurement module, and voltage measurement adopts voltage divider network to combine voltage detection instrument fortune to put, and the output access high accuracy single-ended AD module is put to the fortune of current and voltage, inserts single chip module by the SPI interface, refers to as shown in fig. 4. Wherein, the amplification factor of the operational amplifier special for current detection is 20 times; the design of the current detecting resistor and the voltage dividing network depends on the range of the current and the voltage to be detected; the operational amplifier of the voltage detection instrument for measuring the voltage is of a high-resistance input type, and the specific amplification factor depends on the design; the AD module selects a high-precision multi-channel single-ended input and SPI interface type ADS1256 module, and is convenient to communicate with the single chip microcomputer module. The 5V, 12V and 3.3V power supplies required by the parts are provided by the auxiliary power supply unit.

The first relay driving module adopts an optical coupling isolation combined triode driving mode, the basic circuit structure is shown in figure 5, figure 5 shows a traditional scheme for driving a 12V relay, the low level is effective, and element selection needs to be adjusted according to specific design.

If a plurality of switching power supplies are connected in parallel, power lines and control interfaces are connected, each switching power supply module corresponds to one alternating current input interface, direct current output interfaces of all the switching power supply modules are connected together, and the first voltage and current module is used for measuring voltage and current and then is connected to the first relay.

In this embodiment, an external energy storage battery pack is further provided, and the external energy storage battery pack is a 24V lithium ion battery pack with a diagnostic interface, referring to fig. 1 and 2. The external energy storage battery pack and the switch power supply form a dual power supply, and the external energy storage battery pack is connected to the direct current input bus and used for stabilizing the voltage of the direct current input bus and supplying power to the direct current power supply system when the switch power supply module fails.

(2) For the power management unit, referring to fig. 1, fig. 2 and fig. 3, the power management unit is connected with the switching power supply unit, the external energy storage battery pack, the upper computer and the voltage stabilizing and current divider unit; the power management unit comprises a constant voltage current-limiting DC-DC unit, an auxiliary power supply unit, a battery pack balancing and protecting unit and a main control unit. Wherein:

with further reference to fig. 2, the constant voltage current-limiting DC-DC unit includes a constant voltage current-limiting DC-DC conversion module and a constant voltage current-limiting detection module. The constant voltage current-limiting detection module is connected with the constant voltage current-limiting DC-DC conversion module, is used for monitoring the state of the constant voltage current-limiting detection module, and comprises a second voltage and current measurement module, a current control module and a second single chip microcomputer module. The switching power supply module is connected to the direct current input bus through the first relay and the constant voltage current limiting DC-DC conversion module. The second voltage and current measuring module is connected with the output end of the constant-voltage current-limiting DC-DC conversion module and used for collecting output voltage and current information of the constant-voltage current-limiting DC-DC conversion module and transmitting the output voltage and current information to the second single chip microcomputer module. The current control module is connected with the second single chip microcomputer module and the constant-voltage current-limiting DC-DC conversion module and is used for controlling the current limiting value of the constant-voltage current-limiting DC-DC conversion module.

In the embodiment, the constant-voltage current-limiting DC-DC conversion module is of a Buck type, rated input DC 9-60V and output DC 3-56V are required to be adjustable, the nominal maximum power is 500W, the nominal efficiency is 97%, and a plurality of constant-voltage current-limiting DC-DC conversion modules can be directly connected in parallel. In order to improve the output power, the output interface of the constant-voltage current-limiting DC-DC conversion module can be directly connected into the direct-current bus in parallel. The constant-voltage current-limiting DC-DC conversion module interface comprises a current external control signal interface, a main chip enable control interface, an output current signal interface, an external synchronous signal interface, a spread spectrum modulation selection interface, a main chip enable interface and a GND interface. The output current of the single constant voltage current-limiting DC-DC conversion module can be directly connected to the second voltage current measurement module together with the output voltage by using the output current signal provided by the output current signal interface, as shown in fig. 2.

In this embodiment, the output voltage is fixed to the maximum allowable voltage value of the battery pack by the regulation potentiometer RX1 of the constant-voltage current-limiting DC-DC conversion module. And the current control module is used for controlling voltage for the current external control signal interface and controlling the current limiting value of the constant-voltage current-limiting DC-DC conversion module. Each constant-voltage current-limiting DC-DC conversion module needs to be equipped with a current control module, and each current control module adopts a DA module in combination with a voltage detection instrument operational amplifier, as shown in fig. 6. In the embodiment, a 16-bit high-precision digital-to-analog conversion module DAC8552 is selected as a DA module of the current control module, the output voltage is 0-5V, the amplification factor of the operational amplifier of the voltage detection instrument is determined according to the design current requirement and a current external control signal interface formula, and the power supply of the DA module and the operational amplifier of the voltage detection instrument is provided by an auxiliary power supply. The second voltage and current measurement module and the current control module are connected to an SPI (serial peripheral interface) of the second single chip microcomputer module, and the main chip enabling control interface and the main chip enabling interface are connected to a digital IO (input/output) port of the second single chip microcomputer module.

Referring to fig. 2, in this embodiment, the auxiliary power supply unit is connected to an output end of the constant voltage current-limiting DC-DC conversion module, and is configured to supply power to the switching power supply unit, the power management unit, the single chip microcomputer modules of the voltage stabilizing and shunt unit, the voltage and current measurement modules, and the MOS drivers when the switching power supply module and the external energy storage battery pack are in failure, so that the system can operate normally when the switching power supply module and the external energy storage battery pack are in failure.

The auxiliary power supply unit comprises an auxiliary power supply module and an auxiliary power supply detection module. The auxiliary power supply module comprises a first DC-DC conversion module, a UPS module, a black start switch, a second DC-DC conversion module and an internal energy storage battery pack; the auxiliary power supply detection module comprises a third voltage and current measurement module, a fourth voltage and current measurement module, a fifth voltage and current measurement module and a third single chip microcomputer module. Wherein: the first DC-DC conversion module is connected to a direct current input bus, the output end of the first DC-DC conversion module is connected with the input end of the UPS module, the internal energy storage battery pack is connected with the input end of the UPS module, the output end of the UPS module is connected with the black start switch, the output end of the black start switch is connected to the second DC-DC conversion module, and the second DC-DC conversion module is used for outputting auxiliary power supply voltages with different voltage levels and providing power supply voltages for monitoring components of the switching power supply unit, the power supply management unit and the voltage stabilizing and current divider unit. The third voltage and current measuring module is connected with the output end of the first DC-DC conversion module and used for collecting output voltage and current information of the first DC-DC conversion module and transmitting the output voltage and current information to the third single chip microcomputer module so as to monitor the first DC-DC conversion module. The fourth voltage and current measuring module is connected with the output end of the internal energy storage battery pack and used for collecting output voltage and current information of the internal energy storage battery pack and transmitting the output voltage and current information to the third single chip microcomputer module to monitor the internal energy storage battery pack. And the fifth voltage and current measuring module is connected with the output end of the black start switch and used for collecting the output voltage and current information of the black start switch and transmitting the output voltage and current information to the third single chip microcomputer module.

In this embodiment, the auxiliary power supply supplies power to the monitoring, control and communication circuits of the entire dc power supply system. The first DC-DC conversion module adopts a 24V input and 5V regulated output 30W type module K240506, and the output of the first DC-DC conversion module is monitored by a third voltage and current measurement module. The UPS module is formed by connecting a plurality of MP2636 power management modules in parallel, the input voltage range of the UPS module is 4.5-6.0V, the output voltage is 5V, a battery interface is compatible with a 3.7V lithium ion battery, the maximum charging voltage is 4.2V, and the total output power is 30W. The internal energy storage battery pack is designed to have a capacity of 10Ah by using a 3.7V parallel lithium ion battery pack, and the output of the internal energy storage battery pack is monitored by a fourth voltage and current measuring module. The black start switch is of a self-locking type, and the output of the black start switch is monitored by a fifth voltage and current measuring module. The black start switch is led out of the power supply system box by a 2-core waterproof plug. The second DC-DC conversion module comprises modules of 5V to 3.3V, 5V to 12V, 5V to +/-12V and the like, wherein: a Buck type second DC-DC conversion module is selected as a 5V to 3.3V module, and a Boost type second DC-DC conversion module is selected as a 5V to 12V and 5V to +/-12V module.

In this embodiment, the third voltage/current measurement module, the fourth voltage/current measurement module, and the fifth voltage/current measurement module are structurally identical to the first voltage/current measurement module, as shown in fig. 4, and the third voltage/current measurement module, the fourth voltage/current measurement module, and the fifth voltage/current measurement module are connected to the SPI interface of the third single chip microcomputer module.

Referring to fig. 2, the power management unit of this embodiment is further configured with a battery pack balancing and protecting unit, where the battery pack balancing and protecting unit is configured to monitor a state of an external energy storage battery pack and includes a protection balancing module, a second relay driving module, a fourth single chip module, a sixth voltage and current measuring module, and a seventh voltage and current measuring module. Wherein: and the protection balancing module is connected to a middle tap of the external energy storage battery pack and is used for detecting the voltage of the single battery and protecting and balancing the single battery. The protection balancing module is connected to the direct current input bus through a second relay; the second relay driving module is connected with the second relay and the fourth single chip microcomputer module and used for controlling the on-off of the second relay. The sixth voltage and current measuring module is connected with the protection balancing module and used for collecting output voltage and current information of the protection balancing module and transmitting the output voltage and current information to the fourth single chip microcomputer module. And the seventh voltage and current measuring module is connected with a middle tap of the external energy storage battery pack and used for acquiring the voltage of the middle tap of the external energy storage battery pack and transmitting the voltage to the fourth singlechip module.

In this embodiment, the protection balancing module is of a 100A same-mouth type, and the module needs to be connected to a middle tap of an external energy storage battery pack to detect the voltage of a single battery for protection and balancing. The protection balancing module has overcharge and over-discharge voltage protection, overcurrent protection, short-circuit protection and temperature control protection. And the protection balancing module is monitored by the sixth voltage and current measuring module and is connected to a direct current bus of the direct current power supply system through the second relay. The second relay drive is the same as the first relay drive, and both adopt an optical coupling isolation combined triode drive mode, as shown in fig. 5. The voltage of the middle tap V0-V8 of the external energy storage battery pack with the diagnosis interface is monitored by an 8-way seventh voltage and current measuring module, and the voltage is realized by an LTC6804 chip and is connected with a fourth single chip microcomputer module through an SPI interface.

With further reference to fig. 2, the power management unit of this embodiment further includes a main control unit, where the main control unit includes an FPGA main control module, a CAN bus module, a dual SD card module, and a serial port driver module. Wherein: the CAN bus module comprises a first path of CAN bus and a second path of CAN bus. The first single chip microcomputer module of the switching power supply unit, the second single chip microcomputer module, the third single chip microcomputer module and the fourth single chip microcomputer module of the power supply management unit are connected with the FPGA main control module through a first path of CAN bus. The FPGA main control module is connected with the environment monitoring module through a second path of CAN bus, and the environment monitoring module comprises a plurality of sensors for monitoring external environment information. The upper computer is connected to the FPGA main control module through the serial port driving module, and the double SD card module is connected with the FPGA main control module.

The direct current power supply system is also provided with an environment monitoring module and an external environment monitoring interface, and all the external environment monitoring modules which accord with the CAN bus communication protocol CAN be directly connected into the direct current power supply system through the external environment monitoring interface. The user can freely dispose the sensor type of environmental monitoring module according to power application environment, for example unmanned ship application can carry on humiture, vibration and the sensor that leaks, and application can carry on pressure, leak and humiture sensor etc. under water. The data are uploaded to the FPGA main control module, external environment data can be provided for the power supply system, the external environment data are fused with all module parts and load monitoring data in the power supply in the FPGA main control module, higher-level fault positioning, diagnosis and even fault prediction can be carried out, self protection is carried out through measures such as output switching-off and the like, or power-off protection is carried out on corresponding loads.

In this embodiment, the FPGA master control module selects a homemade core board based on the ALTERA Cyclone IV. The CAN bus module is divided into two paths: all the singlechip modules and the shunt interfaces are connected into a first path of CAN bus through a CAN transceiver; an external environment monitoring module is connected into a second path of CAN bus by a 4-core waterproof connector through a CAN transceiver, and the circuit structure of the two paths of CAN buses is shown in figure 7. The serial port driving module selects a TTL-to-422 serial port module, a full-duplex mode is adopted, output is isolated, and a 5-core waterproof plug is connected to an upper computer. The double SD card modules are two independent SPI interface SD card circuits and are used for data recording.

(3) As for the voltage stabilizing and current dividing unit, referring to fig. 1 and 8, the voltage stabilizing and current dividing unit includes a DC-DC voltage stabilizing unit and a current dividing unit. The DC-DC voltage stabilizing unit comprises at least one voltage-grade voltage stabilizing DC-DC conversion module, and each voltage stabilizing DC-DC conversion module is connected with the power supply management unit and used for outputting at least one voltage-grade direct-current voltage stabilizing power supply. The current divider unit comprises a wide voltage output current divider and at least one voltage-stabilizing output current divider; the wide-voltage output current divider is connected with the power management unit and an external wide-voltage load through a direct-current input bus; each voltage-stabilizing DC-DC conversion module is connected to an external load through a voltage-stabilizing output shunt.

As further shown in fig. 1 and 8, since the DC load of the marine instrument is various, and therefore the DC power supply system needs to be expanded according to the voltage requirement, the DC-DC voltage stabilizing unit in this embodiment is provided with a plurality of voltage-level voltage-stabilizing DC-DC conversion modules, and the DC-DC voltage stabilizing unit in this embodiment is specifically provided with a plurality of 24V voltage-stabilizing DC-DC conversion modules and a plurality of 12V voltage-stabilizing DC-DC conversion modules, and has three voltage levels: the battery pack has wide voltage, 24V and 12V, and the output voltage of each grade is respectively connected to a plurality of loads through a current divider. In the embodiment, the DC-DC voltage stabilizing unit requires to output a 24V voltage stabilizing power supply and a 12V voltage stabilizing power supply, so that two voltage levels of voltage stabilizing DC-DC conversion modules are selected. And selecting a C242430 module with nominal input voltage of 15-40V, nominal output of 24V and nominal maximum current of 30A to form a 24V voltage-stabilized power supply, wherein the number of the 24V voltage-stabilized DC-DC conversion modules is determined according to the load requirement. The 12V stabilized voltage power supply is formed by selecting C241230 modules with nominal input voltage of 15-40V, nominal output of 12V and nominal maximum current of 30A, and the number of the 12V stabilized DC-DC conversion modules is determined according to the load requirement. The input ends of the 24V voltage-stabilizing DC-DC conversion module and the 12V voltage-stabilizing DC-DC conversion module are connected with a DC input bus, and the output ends are connected with respective voltage-stabilizing output shunts. It should be noted that if other voltage classes are required, a voltage stabilizing DC-DC conversion module with nominal input voltage of 15-40V and corresponding output voltage and current can be selected according to load power to form a voltage stabilizing power supply.

Referring further to fig. 8, in the present embodiment, a wide voltage output shunt and a regulated voltage output shunt are provided, wherein the regulated voltage output shunt further includes a 24V regulated voltage output shunt for a 24V regulated voltage supply and a 12V regulated voltage output shunt for a 12V regulated voltage supply. Wherein: the wide voltage output splitter is used to distribute the dc input bus voltage (i.e., the external energy storage battery pack output voltage) directly to a plurality of external wide voltage loads. The voltage stabilizing output current divider is used for outputting and connecting the voltage stabilizing DC-DC conversion modules of the DC-DC voltage stabilizing units at various voltage levels in parallel and distributing the direct-current voltage stabilizing power supply of each voltage level to an external load. Specifically, the method comprises the following steps:

for the wide voltage output current divider, as further shown in fig. 8, the wide voltage output current divider includes a fifth single chip microcomputer module, a sixth single chip microcomputer module, an MOS transistor driving circuit, a dual MOS transistor, a fuse, a plurality of eighth voltage and current measurement modules, an auxiliary power supply interface, and a load interface. Wherein: each load output connected with the direct current input bus is subjected to switch control through double MOS tubes, and each double MOS tube is connected with the direct current input bus and then connected to an external wide voltage load through a fuse and a load interface. The MOS tube driving circuit is connected with the sixth singlechip module and each double MOS tube and is used for controlling the on-off state of each double MOS tube. And the output end of each fuse is connected with an eighth voltage and current measuring module respectively, and the eighth voltage and current measuring module is used for acquiring voltage and current information of the external wide voltage load output by each load and transmitting the voltage and current information to the fifth single chip microcomputer module to monitor the state of each external wide voltage load. The auxiliary power supply interface of the wide-voltage output shunt is connected to the auxiliary power supply output interface of the power supply management unit; and the wide-voltage output current divider is connected with the FPGA main control module through the first path of CAN bus.

In this embodiment, the number of load interfaces output by the wide voltage output splitter needs to be determined according to the external wide voltage load requirement. Each output is relatively independent, and fig. 8 only shows a structural diagram of three load outputs. And each eighth voltage and current measuring module is connected to the fifth singlechip module through an SPI bus. The values of the fuse and the elements of each voltage and current measuring module depend on the designed output power. The double MOS tubes are formed by directly connecting two low-conduction internal resistance N-channel MOS tubes in parallel, and a drive circuit of the double MOS tubes is of a high-side type, as shown in fig. 9.

And for the voltage stabilizing output shunt, the voltage stabilizing output shunt is used for connecting the outputs of the voltage stabilizing DC-DC conversion modules of a plurality of voltage levels of the DC-DC voltage stabilizing unit in parallel. In the embodiment, two levels of voltage stabilization output shunts are provided, and the voltage stabilization output shunts connect the outputs of the 24V or 12V voltage stabilization modules in parallel and distribute the outputs to corresponding external loads. The 24V regulated output shunt of the 24V regulated power supply will be described, and the structure of the 12V regulated output shunt is identical to that of the 24V regulated output shunt, and will not be described in detail in this embodiment.

As further shown in fig. 8, the voltage stabilizing output current divider includes a seventh single chip module, an eighth single chip module, a ninth single chip module, a MOS transistor driving circuit, a dual MOS transistor, a fuse, an ideal diode, a plurality of ninth voltage and current measuring modules, a tenth voltage and current measuring module, a plurality of eleventh voltage and current measuring modules, an auxiliary power interface, and a load interface. Because the voltage-stabilizing DC-DC conversion modules can not be directly connected in parallel, after the voltage-stabilizing output current divider is connected, the output end of each voltage-stabilizing DC-DC conversion module is respectively connected with a ninth voltage and current measuring module for collecting the voltage and current information output by each voltage-stabilizing DC-DC conversion module and transmitting the voltage and current information to the seventh single chip microcomputer module to monitor the state of each voltage-stabilizing DC-DC conversion module. Each voltage-stabilizing DC-DC conversion module is connected with an ideal diode module in series to form a direct-current voltage-stabilizing bus (24V); and the tenth voltage and current measuring module is connected with the direct-current voltage-stabilizing bus (24V) and is used for acquiring voltage and current information of the direct-current voltage-stabilizing bus (24V), transmitting the voltage and current information to the seventh single chip microcomputer module and monitoring the direct-current voltage-stabilizing bus (24V). Each load output connected with the direct current voltage-stabilizing bus (24V) is switched on and off through double MOS tubes, and each double MOS tube is connected with the direct current voltage-stabilizing bus (24V) and then is connected with an external load through a fuse and a load interface; the MOS tube driving circuit is connected with the eighth singlechip module and each double MOS tube and is used for controlling the on-off state of each double MOS tube. And the output end of each fuse is connected with an eleventh voltage and current measuring module respectively and is used for acquiring the voltage and current information of the external load output by each load, monitoring the state of each external load and transmitting the state to the ninth singlechip module. The auxiliary power supply interface of each voltage stabilizing output shunt is connected to the auxiliary power supply output interface of the power supply management unit; each voltage stabilizing output current divider is connected with the FPGA main control module through a first CAN bus.

It should be noted that, in this embodiment, the load interfaces of the regulated output shunts of different voltage classes are implemented by waterproof aviation plugs with different core numbers, so as to prevent the power problem caused by accidental misconnection of users.

In this embodiment, each of the single chip microcomputer modules of the switching power supply unit, the power supply management unit, and the voltage stabilizing and current divider unit all employs an STM32 single chip microcomputer.

For the dc power supply system provided in this embodiment, the external interfaces thereof are divided into 9 types: (1) the number of the alternating current input interfaces is consistent with that of the switching power supply modules; (2) the wide-voltage load power supply interfaces are designed according to the requirement; (3)24V load power supply interfaces, the number of which is designed according to requirements; (4) the 12V load power supply interfaces are designed according to the requirement; (5) the external monitoring interfaces are designed in quantity according to requirements; (6) 1 positive and negative electrode interfaces of the battery pack; (7) 1 battery pack diagnosis interface; (8) 1 external communication interface; (9) black start switch interface, 1. All the interfaces are realized by adopting waterproof aviation plugs.

Secondly, software design:

the software of the direct current power supply system adopts a layered design, and as shown in reference to fig. 10-12, the software part comprises a bottom layer single chip microcomputer software module, a middle layer CAN bus communication module and a top layer FPGA software module. Specifically, the method comprises the following steps:

(1) for the single chip microcomputer software module, the single chip microcomputer software runs in each single chip microcomputer module of the switching power supply unit, the power supply management unit and the voltage stabilizing and current dividing unit, and is responsible for reading AD values in each voltage and current measuring module, writing DA values in the current control module, writing first relay drive, second relay drive and MOS drive control signals, and communicating with each DC-DC conversion module.

The single chip microcomputer software mainly comprises the steps of reading voltage and current measured values, primarily diagnosing and isolating faults, sending control commands, CAN communication and the like, the flow is shown in figure 11, and specific codes are arranged in the flow chart and are slightly different according to modules connected with the single chip microcomputer modules. For example, in the first single chip microcomputer module of the switching power supply unit shown in fig. 2, reading a voltage and current measurement value of the switching power supply is in an SPI communication mode, and simultaneously, reading a TTL digital value on a communication interface of the switching power supply regarding a state of the switching power supply, if a voltage abnormality is found through diagnosis, performing fault isolation by turning off operations such as a first relay, and sending an abnormality report to an upper computer and turning off the output of the switching power supply. However, the seventh one-chip microcomputer module in the voltage stabilization output shunt shown in fig. 8 only uses the SPI interface to read the voltage and current measurement values, and has no flow of sending the control signal.

The single chip microcomputer software reads the numerical value in polling and answering communication, and each single chip microcomputer module circularly measures the numerical values of all the connecting modules, smoothes and stores the data and carries out preliminary diagnosis. The communication process with the FPGA main control module is a response type, the FPGA main control module sends out a request communication frame, each sensor on different single chip microcomputer modules has a unique address, and the single chip microcomputer modules judge whether to respond or not according to the addresses and return corresponding data. The fault diagnosis information is transmitted in a single direction and is only transmitted to the FPGA main control module by each singlechip module. The control signal is sent in a one-way communication mode, the FPGA main control module sends control requests to the single chip microcomputer modules, and the single chip microcomputer modules operate the relevant modules according to the control commands.

(2) The CAN bus communication module runs in each single chip microcomputer module of the switching power supply unit, the power supply management unit, the voltage stabilizing and current divider unit and the FPGA main control module and is used for communication between each single chip microcomputer module and the FPGA main control module. The CAN bus communication in this embodiment is based on the pseudo-MODBUS protocol, and communicates various sensor values, control signals and FPGA modules, and the data frame format is as follows:

TABLE 1 CAN COMMUNICATION PROTOCOL DATA FRAME FORMAT

Device address	Function code	Data address	Data format	CRC checking
					1 byte	1 byte	2 bytes	16 bytes	2 bytes

The fields are defined as table 2 below:

TABLE 2 definition of fields of CAN communication protocol data frame

For example: the FPGA main control module requests the measurement values of the voltage and current sensors of the auxiliary power supply external energy storage battery pack in the power management unit, and the messages are as follows:

the third singlechip module of the power management unit responds to the last message, and the returned data is as follows:

the environment monitoring module warns humidity anomaly (the specific diagnosis result is a humidity value), and the message is as follows:

the FPGA main control module sends a command of closing the No. 05 MOS tube to the voltage stabilization output current divider, and the message is as follows:

(3) the FPGA software module runs in the FPGA main control module, and is configured to summarize, store, diagnose and isolate status information of each monitoring component, information of each internal sensor, and information of the environment monitoring module of the external energy storage battery pack, the switching power supply unit, the power management unit, the voltage stabilizing and current divider unit of the dc power supply system, and perform upper computer communication, where the flow is as shown in fig. 12.

Wherein: in this embodiment, data polling is implemented by using the data polling methods shown in table 1 and table 2, and polling and summarizing the status information of all sensors and components in the dc power supply system and the information of all environment monitoring modules. The fault diagnosis and isolation adopts a fuzzy expert system algorithm, diagnoses the possible faults of each module, component and external environment in the battery pack according to the data and physical significance of each sensor, carries out classification according to the fault degree to obtain alarm and fault information, and isolates the fault module by utilizing switching devices such as a relay, an MOS tube and the like. If serious faults occur, the FPGA main control module sends fault alarm to the upper computer in time and carries out isolation in time. All sensor raw data, diagnostic data, are stored in the SD card every 5 seconds. And meanwhile, the data are packaged and uploaded to an upper computer through a serial port driving module.

Because the auxiliary power supply unit is arranged in the direct-current power supply system, the whole direct-current power supply system can independently operate without depending on alternating-current input and an external energy storage battery pack. Therefore, the black start switch for controlling the output of the auxiliary power supply unit is the only start switch of the entire system. And after the black start switch is turned on, the whole system carries out self-checking. Therefore, the present invention further provides a method for monitoring a dc power supply system according to the above dc power supply system, where a system power-on sequence and a main circuit diagnosis logic are shown in fig. 13, and the method includes:

the method comprises the following steps that a black start switch is closed, the system is electrified and works, and an FPGA main control module polls state information of all parts of an external energy storage battery pack, a switch power supply unit, a power supply management unit and a voltage stabilizing and current divider unit; and determining the working mode of the direct-current power supply system according to the states of the switching power supply module and the external energy storage battery pack, wherein the working mode judgment is shown in table 3.

In the main circuit, a switch power supply module is connected with a normally open contact of a first relay, and an external energy storage battery is connected with a normally closed contact of a second relay. If the output voltage and the output current of the switching power supply module are detected not to reach the normal value within the given time, recording the fault of the switching power supply and keeping the first relay disconnected; and if the voltage of the external energy storage battery pack or the voltage of a certain monomer is abnormal, recording the fault of the external energy storage battery pack and immediately disconnecting the second relay. The above determination is performed cyclically in the working process of the power supply system. If the switching power supply module is normal and the battery pack is abnormal (namely, the mode 2), starting the constant-voltage current-limiting DC-DC conversion module, and simultaneously setting a current-limiting value as a maximum value; if the switching power supply is normal and the battery pack is normal (namely, the mode 3), determining a current limiting value according to the voltage of the external energy storage battery pack, and then starting the constant-voltage current-limiting DC-DC conversion module.

According to the four working states shown in table 3 and the measured data of each voltage and current sensor, the working states of the direct current bus, the auxiliary power supply, the 24V direct current bus in the first voltage stabilization output shunt and the 12V direct current bus in the second voltage stabilization output shunt are judged, and whether the double MOS tubes of each voltage stabilization output shunt are started to supply power to the load is determined according to the working states. If the voltage of the direct current input bus is detected to be normal, the double MOS tubes of the wide voltage output current divider are started, and the direct current wide voltage power supply voltage is output; and meanwhile, judging whether the direct-current stabilized voltage bus is normal, if so, starting a double MOS (metal oxide semiconductor) tube of the stabilized voltage output shunt and outputting the voltage of the direct-current stabilized voltage supply.

TABLE 3 working mode determination and DC bus status

In conclusion, the direct-current power supply system provided by the invention provides convenient hardware extension and soft design, and the system is provided with an auxiliary power supply and can complete the state monitoring and communication functions of the power supply system under the condition that the main circuit is powered off. (1) The main circuit of the direct current power supply system is provided with a switching power supply, a constant voltage current-limiting DC-DC conversion module, a voltage-stabilizing DC-DC conversion module, an ideal diode module and an auxiliary power supply, and the output voltage grade can be expanded or changed without modifying the structure of a power supply management part as long as the voltage-stabilizing DC-DC conversion module is added or replaced according to needs. Each time a voltage class is expanded, a matching shunt is required, the monitoring signal on the new shunt CAN be directly connected to the first CAN bus CAN1, and a new device address is defined according to the communication protocols shown in tables 1 and 2. (2) The internal software of the direct current power supply system adopts a layered design, the measurement and control of a single chip microcomputer at the bottom layer and the FPGA main control at the upper layer are layered, and the middle parts are connected through unified CAN bus communication. The design method reduces the development difficulty and is beneficial to the collaborative development of multiple persons. Developers only need to pay attention to programming between each single chip microcomputer module and connected functional modules (such as voltage and current measurement, relay drive and the like), and although specific programs among different single chip microcomputer modules are different, communication formats of the single chip microcomputer modules to the FPGA main control module are unified. Due to the expandability of the CAN bus, if the shunt needs to be expanded, only the single chip microcomputer module in the shunt circuit needs to be connected into the first CAN bus CAN1, and if the external environment monitoring module needs to be expanded, only the new environment monitoring module needs to be connected into the second CAN bus CAN 2. No matter how the single chip microcomputer part and the external environment monitoring module are expanded, the program of the FPGA main control module is not changed, the communication part basically does not need to be changed, and only a new equipment address needs to be added. (3) In the direct-current power supply system, the input and output voltage and current of each module are monitored, the fault type possibly occurring in the module is judged and positioned by using a certain fault diagnosis algorithm, and the fault module is isolated by using a relay, a module enable switch and the like. Meanwhile, the voltage and the current of the external load are monitored in real time, faults such as power failure and short circuit of load equipment can be given, and the fault equipment is turned off in time through the MOS tube, so that the safety of a power supply system is guaranteed. Monitoring data and fault diagnosis results can be uploaded to an upper computer system through the FPGA main control module, and the upper computer system is used for displaying and alarming in real time. (4) The auxiliary power supply built in the system is also normally operated under the condition that the main circuit is powered off, and the single chip microcomputer modules, the voltage and current measuring modules, the MOS drive monitoring modules and the like can normally operate, so that the main circuit can be detected, diagnosed and controlled. The auxiliary power supply adopts an online UPS working mode, and when the direct current bus voltage of the main circuit is normal, the auxiliary power supply charges the battery pack and supplies power to the monitoring module; when the direct current bus is powered off, the auxiliary power supply is seamlessly switched to the battery for power supply, so that the normal work of the monitoring module is ensured. The auxiliary power supply can guarantee the independent operation of the system monitoring part, and can still complete the monitoring, diagnosis and communication functions when the main circuit fails, so that a user can directly monitor the data and diagnosis results of the internal part, the load and the environment monitoring module of the power supply system on the upper computer, the maintainability of the whole power supply system is improved, the reliability of the system can be improved, and the maintenance cost can be reduced. The direct-current power supply system can be further expanded into a fault Prediction and Health Management (PHM) platform of the whole marine instrument and equipment.

Claims

1. A direct current power supply system comprises a hardware part, and is characterized in that the hardware part comprises an external energy storage battery pack, an upper computer, a switching power supply unit, a power supply management unit, a voltage stabilizing and current divider unit;

2. The direct-current power supply system according to claim 1, wherein the switching power supply detection module comprises a first relay, a first relay driving module, a first voltage and current measurement module, and a first single chip microcomputer module; the direct current output end of the switching power supply module is connected to the first relay; the first relay driving module is connected with the first singlechip module and the first relay and is used for controlling the on-off of the first relay; the first voltage and current measuring module is connected to the direct current output end of the switching power supply module and used for collecting output voltage and current information of the switching power supply module and transmitting the output voltage and current information to the first single chip microcomputer module.

3. The direct-current power supply system of claim 2, wherein the constant-voltage current-limiting detection module comprises a second voltage-current measurement module, a current control module and a second single-chip microcomputer module; the constant-voltage current-limiting DC-DC conversion module is connected with the output end of the switching power supply module through the first relay; the second voltage and current measuring module is connected with the output end of the constant voltage current-limiting DC-DC conversion module and is used for collecting output voltage and current information of the constant voltage current-limiting DC-DC conversion module and transmitting the output voltage and current information to the second single chip microcomputer module; the current control module is connected with the second single chip microcomputer module and the constant-voltage current-limiting DC-DC conversion module and is used for controlling the current limiting value of the constant-voltage current-limiting DC-DC conversion module.

4. The DC power supply system of any one of claims 1-3, wherein the auxiliary power module comprises a first DC-DC conversion module, a UPS module, a second DC-DC conversion module, an internal energy storage battery pack, a black start switch;

5. The DC power supply system of claim 4, wherein the power management unit further comprises a battery pack balancing and protection unit; the battery pack balancing and protecting unit comprises a protection balancing module, a second relay driving module, a fourth single chip microcomputer module, a sixth voltage and current measuring module and a seventh voltage and current measuring module;

6. The direct-current power supply system of claim 5, wherein the main control unit comprises an FPGA main control module, a CAN bus module and a serial port drive module;

7. The direct-current power supply system according to claim 6, wherein the wide-voltage output current divider comprises a fifth single-chip microcomputer module, a sixth single-chip microcomputer module, a plurality of eighth voltage and current measuring modules, an MOS (metal oxide semiconductor) tube driving circuit, a double MOS tube, a fuse, an auxiliary power supply interface and a load interface;

8. The direct-current power supply system according to claim 7, wherein the voltage-stabilizing output current divider comprises a seventh single-chip microcomputer module, an eighth single-chip microcomputer module, a ninth single-chip microcomputer module, a plurality of ninth voltage and current measuring modules, a tenth voltage and current measuring module, a plurality of eleventh voltage and current measuring modules, a MOS (metal oxide semiconductor) tube driving circuit, a double MOS tube, a fuse, an ideal diode, an auxiliary power supply interface and a load interface;

9. The direct current power supply system of any one of claims 6 to 8, further comprising a software portion, the software portion comprising a bottom layer single chip microcomputer software module, a middle layer CAN bus communication module, a top layer FPGA software module;

10. A dc power supply system monitoring method, characterized in that the dc power supply system according to any one of claims 1 to 9 is used, comprising: