Ship power grid system and power matching method thereof

Abstract

The invention discloses a ship power grid system and a power matching method thereof, and relates to the technical field of ship electric power. The method comprises the following steps: acquiring the voltage of a busbar and the current of a load branch of a ship power grid system through an analog quantity acquisition module; filtering the voltage of the busbar and the current of the load branch by adopting a preset filtering algorithm, and determining the current load rate of the ship power grid system according to the filtered voltage and current; adjusting the output power of the tandem shaft propulsion motor according to the current load rate of the ship power grid system; and the fault of the ship power grid system is identified and positioned. According to the method, power matching of the ship power grid system can be realized, reliable operation of power matching is guaranteed, and the reliability of the system is improved. And the voltage of the busbar and the current of the load branch are filtered before the load rate is calculated, so that the response capability of power matching can be improved, and the response capability and reliability of the whole system are further improved.

Description

Technical Field

[0001] The present application relates to the field of ship power technology, and in particular to a ship power grid system and a power matching method thereof. Background Art

[0002] The electric propulsion system in the ship power grid system usually uses a series shaft motor, and two propulsion motors are configured at the front and rear power stations of the ship. Since the power distribution of the series shaft propulsion motor is different under the two working conditions of the front and rear power stations being separated or connected to the grid, it is necessary to develop a power matching method suitable for different application conditions. However, the power matching strategy of the existing ship power grid system does not identify and handle faults, so the system reliability is relatively poor. Summary of the invention

[0003] Purpose of the invention: An embodiment of the present application provides a power matching method for a ship power grid system, aiming to overcome the technical problem of poor reliability of the ship power grid system in the prior art; another purpose of an embodiment of the present application is to provide a ship power grid system.

[0004] Technical solution: A power matching method for a ship power grid system described in an embodiment of the present application is applied to the ship power grid system; the ship power grid system comprises: a series shaft propulsion motor, an analog quantity acquisition module, a bus bar and a load branch;

[0005] The method comprises:

[0006] The analog quantity acquisition module is used to acquire the voltage of the busbar and the current of the load branch of the ship power grid system;

[0007] Using a preset filtering algorithm to filter the voltage of the bus and the current of the load branch, and determining the current load rate of the ship power grid system according to the filtered voltage and current;

[0008] The output power of the tandem-shaft propulsion motor is adjusted according to the current load rate of the ship's power grid system; and the fault of the ship's power grid system is identified and located.

[0009] In some embodiments, the preset filtering algorithm includes:

[0010] The target analog quantity acquisition channel is sampled for a preset number of times, and each sampling continuously collects a preset number of sampling points;

[0011] Calculate the average value of the preset number of sampling points for each sampling, and record it as a first average value;

[0012] Filter and eliminate the maximum and minimum values ​​in the first average values ​​sampled at the preset sampling times;

[0013] The average of the first average values ​​sampled at a preset number of sampling times after excluding the maximum value and the minimum value is calculated and recorded as the second average value.

[0014] In some embodiments, the calculation formula of the second average value is:

[0015]

[0016] x(K)=(x(1)+x(2)+......+x(M)) / M

[0017] P=max{x(K)+(K-1)+(K-2)+......+x(KN)}

[0018] Q=min{x(K)+(K-1)+(K-2)+......+x(KN)}

[0019] in, is the second average value; N is the preset sampling number; M is the preset number; x(i) is the first average value of the i-th sampling; P is the maximum value of the first average value sampled at the preset sampling number; Q is the minimum value of the first average value sampled at the preset sampling number; x(K) is the average value of the M sampling points collected at time K.

[0020] In some embodiments, determining the current load rate of the ship power grid system according to the filtered voltage and current includes:

[0021] Calculate the real-time power of the first type of load in the ship power grid system according to the filtered voltage and current;

[0022] Determining the maximum power of the second type of load in the ship power grid system and the rated power of the generator set in the ship power grid system;

[0023] The current load rate of the ship power grid system is calculated according to the real-time power of the first type of load, the maximum power of the second type of load and the rated power of the generator set.

[0024] In some embodiments, the current load rate is calculated as follows:

[0025]

[0026] Among them, P i is the maximum power of m second-class loads, P j is the real-time power of n first-class loads, P k is the rated power of k generator sets.

[0027] In some embodiments, the ship power grid system further includes a switch output module; and adjusting the output power of the tandem propulsion motor according to the current load rate of the ship power grid system includes:

[0028] When the current load rate of the ship power grid system is greater than or equal to a first preset load rate, a fast power limiting signal is output to the frequency converter of the tandem shaft propulsion motor through the switch output module;

[0029] When the current load rate of the ship power grid system is greater than or equal to a second preset load rate, an emergency power limiting signal is output to the frequency converter of the tandem shaft propulsion motor through the switch output module.

[0030] In some embodiments, the first preset load rate is less than the second preset load rate.

[0031] In some embodiments, the ship power grid system includes a front power station and a rear power station; the front power station and the rear power station are respectively provided with two power matching units; and the two power matching units of the front power station are mutually redundant, and the two power matching units of the rear power station are mutually redundant; the power matching unit at least includes a communication module and an optical fiber ring network;

[0032] The identifying and locating the fault of the ship power grid system includes:

[0033] When only one of the redundant power matching units has a single fault, the collected data of the normal power matching unit is obtained through the optical fiber ring network;

[0034] When a single fault occurs in the redundant power matching units at the same time, the comprehensive fault is reported to the monitoring network through the communication module;

[0035] When only one of the mutually redundant power matching units has a single fault, and the optical fiber ring networks corresponding to the mutually redundant power matching units have faults at the same time, the comprehensive fault is reported to the monitoring network through the communication module.

[0036] In some embodiments, the power matching unit further includes: a switch quantity acquisition module, the analog quantity acquisition module and a calculation module;

[0037] The single fault includes: at least one of: a disconnection fault of the switch quantity acquisition module, a disconnection fault of the analog quantity acquisition module, a downtime fault of the calculation module, and a communication fault;

[0038] The comprehensive fault includes a data calculation incomplete fault and a power matching unit fault.

[0039] In some embodiments, the identification of the single fault and the combined fault includes:

[0040] When the current value of the analog quantity collected by the analog quantity acquisition module is less than the preset current, it is determined that the analog quantity acquisition module is disconnected;

[0041] When the feedback result of the disconnection detection hardware circuit of the switch quantity acquisition module on the disconnection of the switch quantity is valid, it is determined that the switch quantity acquisition module has a disconnection fault;

[0042] When the central processing unit of the computing module has no heartbeat, it is determined that the computing module is down;

[0043] When the analog quantity data and / or the switch quantity data of the power matching unit are abnormal due to the single fault, it is determined to be the data calculation incomplete fault;

[0044] When at least one of the data calculation incomplete failure and the calculation module downtime failure occurs, it is determined that the power matching unit has a failure.

[0045] Accordingly, a ship power grid system described in an embodiment of the present application includes: a tandem propulsion motor, an analog quantity acquisition module, a bus, a load branch, a filter module, a calculation module, a power regulation module and a fault identification module;

[0046] The analog quantity acquisition module is used to collect the voltage of the busbar and the current of the load branch of the ship power grid system;

[0047] The filtering module is used to filter the voltage of the bus and the current of the load branch using a preset filtering algorithm;

[0048] The calculation module is used to determine the current load rate of the ship power grid system according to the voltage and current after filtering;

[0049] The power regulation module is used to regulate the output power of the tandem propulsion motor according to the current load rate of the ship power grid system;

[0050] The fault identification module is used to identify and locate faults in the ship power grid system.

[0051] In some embodiments, the ship power grid system further includes a front power station and a rear power station; the front power station and the rear power station are respectively provided with two power matching units; and the two power matching units of the front power station are mutually redundant, and the two power matching units of the rear power station are mutually redundant; the power matching unit at least includes a communication module and an optical fiber ring network;

[0052] The fault identification module is also used for:

[0053] When only one of the redundant power matching units has a single fault, the collected data of the normal power matching unit is obtained through the optical fiber ring network;

[0054] When a single fault occurs in the redundant power matching units at the same time, the comprehensive fault is reported to the monitoring network through the communication module;

[0055] When only one of the mutually redundant power matching units has a single fault, and the optical fiber ring networks corresponding to the mutually redundant power matching units have faults at the same time, the comprehensive fault is reported to the monitoring network through the communication module.

[0056] Beneficial effect: Compared with the prior art, the ship power grid system and its power matching method of the embodiment of the present application, the power matching method of the ship power grid system includes: collecting the voltage of the busbar of the ship power grid system and the current of the load branch through the analog quantity acquisition module; filtering the voltage of the busbar and the current of the load branch using a preset filtering algorithm, and determining the current load rate of the ship power grid system according to the voltage and current after filtering; adjusting the output power of the series shaft propulsion motor according to the current load rate of the ship power grid system; and identifying and locating the fault of the ship power grid system. Thus, the real-time load rate of the ship power grid system can be calculated by this method to adjust the output power of the system series shaft propulsion motor and realize the power matching of the ship power grid system. And identify and locate the system fault, discover the system fault in time, ensure the reliable operation of power matching, and improve the reliability of the system. And filtering the voltage of the busbar and the current of the load branch before calculating the load rate can improve the responsiveness of the power matching, thereby improving the responsiveness and reliability of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0058] Figure 1 A schematic diagram of a topological structure of a ship power grid system provided in an embodiment of the present application;

[0059] Figure 2 It is a schematic diagram of the main-standby architecture of the power matching unit provided in an embodiment of the present application;

[0060] Figure 3 It is a schematic diagram of the principle structure of a power matching unit provided in an embodiment of the present application;

[0061] Figure 4It is a schematic diagram of the communication architecture of the ship power grid system provided in an embodiment of the present application;

[0062] Figure 5 It is a schematic diagram of the structure of the distributed system provided in the embodiment of the present application;

[0063] Figure 6 Schematic diagram of the circuit principle of the relay provided in the embodiment of the present application;

[0064] Figure 7 It is a schematic diagram of the circuit structure of the switch signal acquisition and detection provided in the embodiment of the present application;

[0065] Figure 8 is a flow chart of a power matching method for a ship power grid system provided in an embodiment of the present application;

[0066] Fig. 9 It is a schematic diagram of the fault types provided in the embodiments of the present application.

[0067] Reference numerals:

[0068] 10-first power matching unit; 20-second power matching unit; 30-third power matching unit; 40-fourth power matching unit; 11-analog quantity acquisition module; 12-switch quantity acquisition module; 13-analog quantity output module; 14-switch quantity output module; 15-calculation module; 16-fault identification module; 17-communication module. DETAILED DESCRIPTION

[0069] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0070] It should be understood that although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another component. Therefore, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of the present application. As used herein, the term "and / or" includes any one of the associated listed items and all combinations of one or more.

[0071] Those skilled in the art will appreciate that the drawings are only schematic diagrams of example embodiments and may not be to scale. The modules or processes in the drawings are not necessarily required to implement the present application and therefore cannot be used to limit the scope of protection of the present application.

[0072] The electric propulsion system in the ship power grid system usually adopts a series shaft motor, and two propulsion motors are configured at the front and rear power stations of the ship respectively. Since the power distribution of the series shaft propulsion motor is different under the two working conditions of the front and rear power stations being separated or connected to the grid, it is necessary to develop a power matching method suitable for different application conditions. However, the power matching strategy of the ship power grid system in the related art does not set a fault tolerance mechanism, so the system reliability is relatively poor.

[0073] For example, patent 201911219927.3 designs a power limiting controller for an electric propulsion ship energy management system. The controller adopts a redundant design method of "network type + independent hardware" and designs different time response targets for two working conditions: power system overload and power system failure. Paper 10.16443 / j.cnki.31-1420.2015.04.005 proposes a power limiting method for floating crane ship power. This method quickly limits the power of the electric propulsion system by calculating the available power of the ship's power system. However, the research fields of the above two methods are both medium-voltage AC power systems of ships, and the propulsion motors are single-axis motors. They do not involve related research on series-axis motors under medium-voltage DC ship power systems. In addition, neither of the above two methods considers fault-tolerant mechanisms.

[0074] The paper 10.13632 / j.meee.2023.10.018 proposed a power limitation strategy for ship DC power stations. However, the response time of this method is 90ms, which is far from the application requirement of less than 10ms. At the same time, this design method does not consider the fault tolerance mechanism, which greatly reduces the reliability of power matching.

[0075] In view of this, an embodiment of the present application provides a ship power grid system and a power matching method thereof to improve the reliability of the ship power grid system.

[0076] Figure 1 A schematic diagram of the topological structure of a ship power grid system provided in an embodiment of the present application. Figure 1 , DG1~DG6 are diesel generator sets, LM1~LM4 are propulsion motors. Among them, LM1 and LM2 constitute the port side tandem shaft propulsion motor of the ship, and LM3 and LM4 constitute the starboard side tandem shaft propulsion motor of the ship. Among them, the ship power grid system includes the front power station and the rear power station. Among them, LM1 and LM3 are the motors of the front power station, and LM2 and LM4 are the motors of the rear power station. QF1~QF6 are bus tie switches, CS1~CS2 are jumper switches connecting the front and rear power stations, QM1~QM4 are the export circuit breaker switches of the propulsion motor, and QG1~QG6 are the export circuit breaker switches of the diesel generator sets. Among them, 1# busbar-4# busbar is the front power station busbar, and 5# busbar-8# busbar is the rear power station busbar.

[0077] Figure 2 Schematic diagram of the main-backup architecture of the power matching unit provided in the embodiment of the present application. In which, the front power station and the rear power station are respectively provided with two power matching units, that is, the main-backup power matching units are respectively provided. For example, please refer to Figure 2 , the front power station is provided with a first power matching unit 10 and a third power matching unit 30, and the rear power station is provided with a second power matching unit 20 and a fourth power matching unit 40. Among them, the 1# inverter and the 2# inverter are the inverters corresponding to the port tandem shaft propulsion motor, that is, the inverters corresponding to LM1 and LM2. The 3# inverter and the 4# inverter are the inverters corresponding to the starboard tandem shaft propulsion motor, that is, the inverters corresponding to LM3 and LM4. The 1# inverter and the 3# inverter are the load motors of the front power station, and the 2# inverter and the 4# inverter are the load motors of the rear power station.

[0078] The first power matching unit 10, the second power matching unit 20, the third power matching unit 30 and the fourth power matching unit 40 have the same structure. The first power matching unit 10 and the third power matching unit 30 are mutually redundant, and the second power matching unit 20 and the fourth power matching unit 40 are mutually redundant.

[0079] For details, see Figure 2 , the front power station and the rear power station are respectively equipped with two power matching units, one main and one standby. The four power matching units are connected to each other through a fiber optic ring network, and a redundant fault-tolerant mechanism is implemented in both software and hardware. Exemplarily, taking the front power station as an example, when all power matching units function normally, the calculation module corresponding to the main power matching unit (such as the second power matching unit 20) of the rear power station preferentially selects the data collected by the main power matching unit (such as the first power matching unit 10) of the front power station, and the standby power matching unit (such as the fourth power matching unit 40) of the rear power station preferentially selects the data collected by the standby power matching unit (such as the third power matching unit 30) of the front power station. When a module failure occurs in the main power matching unit of the front power station (i.e., a power matching unit failure), the calculation module of the power matching unit of the rear power station will communicate through the fiber optic ring network and select the data collected by the standby power matching unit of the front power station.

[0080] Figure 3 Schematic diagram of the principle structure of a power matching unit provided in the embodiment of the present application. Figure 3, the power matching unit includes: an analog quantity acquisition module 11, a switch quantity acquisition module 12, an analog quantity output module 13, a switch quantity output module 14, a calculation module 15, a fault identification module 16 and a communication module 17. In addition, the ship power grid system also includes a bus, a load branch, a filter module, and a power regulation module. Among them, the filter module, the power regulation module and the calculation module can be integrated in the controller or processor of the ship power grid system, for example, integrated in a control architecture composed of FPGA+ARM, and the control architecture performs filtering processing, load rate calculation and power regulation. Among them, the power matching unit is also used to realize the output of fast unloading instructions, which is not limited by the control part.

[0081] Among them, the analog quantity acquisition module 11 is used to collect the voltage of the busbar and the current of the load branch of the ship power system. The filtering module is used to filter the voltage of the busbar and the current of the load branch using a preset filtering algorithm. The calculation module 15 is used to determine the current load rate of the ship power system according to the voltage and current after filtering. The power regulation module is used to adjust the output power of the series shaft propulsion motor according to the current load rate of the ship power system. The fault identification module 16 is used to identify and locate the fault of the ship power system. Among them, the switch quantity acquisition module 12 is used to collect the on-off state of each bus switch of the ship power system, the on-off state of the jumper switch, the on-off state of the circuit breaker corresponding to the generator set, and the on-off state of the switch corresponding to the load in real time. The analog quantity acquisition module 11 collects the voltage of each busbar and the current of the load branch in real time, and performs filtering processing (it can also be performed by a separate filtering processing module. The specific setting can be made according to the actual situation, and no specific limitation is made here). Among them, the calculation module 15 is also used to identify the topology of the ship power system based on the collected state information of each switch.

[0082] Among them, the analog output module 13 is used to output the current load rate of the ship power grid system calculated by the calculation module 15 in real time. For example, the load rate (or load rate) of the grid-connected generator set in the power supply area where the tandem electric propulsion device is located calculated by the calculation module 15 is output to the tandem propulsion motor in real time to implement dynamic power limitation. The switch output module 14 is used to output the output power of the tandem propulsion motor output by the power regulation module to the frequency converter corresponding to the tandem propulsion motor. For example, the switch signal "fast power limitation" and the switch signal "emergency power limitation" are output to the frequency converter.

[0083] For example, see Figure 3The power matching unit is composed of seven parts: an analog quantity acquisition module 11, a switch quantity acquisition module 12, an analog quantity output module 13, a switch quantity output module 14, a calculation module 15, a fault identification module 16, and a communication module 17. The external system communicates with the power matching unit through the monitoring Ethernet. The switch quantity acquisition module 12 collects the on-off status signals of each circuit breaker in the ship power grid system, and sends the results to the calculation module for topology identification. The analog quantity acquisition module 11 processes the 4-20mA signal, and after data filtering, sends the processing results to the calculation module 15 for further processing. The calculation module 15 converts the calculated load rate into a 4-20mA signal and sends it to the external frequency converter device through the analog quantity output module 13. At the same time, the calculation module 15 sends the load rate over-limit and rapid unloading signals to the external frequency converter device through the switch quantity output module 14. In addition, the fault identification module 16 can detect in real time fault conditions such as analog quantity acquisition module disconnection fault, switch quantity acquisition module disconnection fault, calculation module CPU crash fault, communication fault, incomplete data calculation fault, power matching unit fault, etc., and send them to the external monitoring network through the communication module 17.

[0084] Figure 4 This is a schematic diagram of the communication architecture of the ship power grid system provided in the embodiment of the present application. In the technical solution of the embodiment of the present application, the communication mode of the ship power grid system is a dual redundant real-time control network, which has the advantages of long transmission distance and large data volume. At the same time, in order to improve the reliability of the system, when the real-time network communication is abnormal, a dual redundant CAN network is set as a backup network for the real-time control network. Please refer to Figure 4 , the first power matching unit 10 and the third power matching unit 30 of the front power station communicate through the optical fiber ring network, and the second power matching unit 20 and the fourth power matching unit 40 of the rear power station communicate through the optical fiber ring network. The first power matching unit 10 and the second power matching unit 20, as well as the third power matching unit 30 and the fourth power matching unit 40 also communicate through the optical fiber ring network. In addition, the energy management controller switch and each power matching unit communicate using a dual redundant real-time control network, which can improve the reliability of communication.

[0085] In some embodiments, the fault identification module 16 is also used for: when a single fault occurs in only one of the redundant power matching units, acquiring the collected data of the normal power matching unit through the optical fiber ring network; when a single fault occurs in the redundant power matching units at the same time, reporting the comprehensive fault to the monitoring network through the communication module; when a single fault occurs in only one of the redundant power matching units, and the optical fiber ring networks corresponding to the redundant power matching units fail at the same time, reporting the comprehensive fault to the monitoring network through the communication module.

[0086] Each power matching unit includes a communication module and an optical fiber ring network. The optical fiber ring network is used to realize internal communication, such as communication between power matching units and between a power matching unit and an upper layer. The communication module is used to realize communication between the power matching unit and the outside.

[0087] For example, see Figure 4 , when each power matching unit is operating normally, it will output its own calculation results to the corresponding frequency converter through hard wire (analog quantity + fast relay), and will also report the fault results and calculation results to the monitoring network. When the system is connected to the network, the power matching unit of the front power station needs to obtain the data of the rear power station, and the rear power station also needs to obtain the data of the front power station. At this time, it is assumed that the main power matching unit (such as the first power matching unit 10) and the main power matching unit (such as the second power matching unit 20) have priority to each other, and the backup power matching unit (such as the third power matching unit 30) and the backup power matching unit (such as the fourth power matching unit 40) have priority to each other. When only one of the redundant power matching units has a single fault, the collected data of the normal power matching unit is obtained through the optical fiber ring network corresponding to the normal power matching unit. For example, for the first power matching unit 10, when it is normal, the data of the first power matching unit 10 comes from the optical fiber ring network corresponding to the first power matching unit 10 and the optical fiber ring network corresponding to the third power matching unit 30. When a single fault occurs in the first power matching unit 10 , data of the first power matching unit 10 is derived from the optical fiber ring network corresponding to the third power matching unit 30 and the optical fiber ring network corresponding to the second power matching unit 20 .

[0088] It should be noted that the logic of the power matching unit reporting faults, for the power matching unit, the external hard-wired output port (one of the three fast relays is used to output the switch signal of the module failure), taking the analog data acquisition failure of a certain channel of the first power matching unit 10 as an example, if only the data acquisition of the first power matching unit 10 has a problem, and the data collection of the second power matching unit 20 is fine, then for the first power matching unit 10, it will only report the analog data acquisition failure of the first power matching unit 10 in the monitoring network, and the first power matching unit 10 will still work normally, but the data involved in the calculation comes from the second power matching unit 20. Only when the optical fiber ring network between the first power matching unit 10 and the second power matching unit 20 is broken, the first power matching unit 10 cannot use the data of the second power matching unit 20 (or the analog acquisition failures of the first power matching unit 10 and the second power matching unit 20 fail at the same time), will the communication module failure be reported, and a module failure signal will be hard-wired to the inverter. After receiving the signal, the inverter will assume that the load rate of the first power matching unit 10 and the hard-wired outputs of the two power limits are unreliable, and automatically switch to control by the second power matching unit 20.

[0089] When the redundant power matching units simultaneously have a single fault in the same analog quantity or switch quantity collection, the comprehensive fault is reported to the monitoring network through the communication module. At this time, the communication modules corresponding to all power matching units will report the comprehensive fault and their respective single faults to the monitoring network, thereby ensuring timely identification and response to the fault. For example, assuming that the first power matching unit 10 and the third power matching unit 30 have a single fault at the same time, the comprehensive fault is reported to the monitoring network through the communication module corresponding to at least any one of the first power matching unit 10, the second power matching unit 20, the third power matching unit 30 and the fourth power matching unit 40.

[0090] When only one of the mutually redundant power matching units has a single fault, and the optical fiber ring network corresponding to the mutually redundant power matching units fails at the same time, the comprehensive fault is reported to the monitoring network through the communication module. At this time, the communication modules corresponding to all power matching units will report the comprehensive fault to the monitoring network, thereby ensuring timely identification and response to the fault. For example, assuming that only the third power matching unit 30 has a single fault between the first power matching unit 10 and the third power matching unit 30, and the optical fiber ring network corresponding to the first power matching unit 10 fails at the same time, the comprehensive fault is reported to the monitoring network through the communication module corresponding to at least any one of the first power matching unit 10, the second power matching unit 20, the third power matching unit 30 and the fourth power matching unit 40. In this way, when a system failure occurs, the normal operation of other devices can be ensured, thereby improving the reliability of the system.

[0091] The fault identification module 16 is also used to identify and locate single faults and comprehensive faults. Single faults include disconnection faults of the switch quantity acquisition module, disconnection faults of the analog quantity acquisition module, downtime faults of the calculation module, and communication faults. Comprehensive faults include incomplete data calculation faults and power matching unit faults.

[0092] Figure 5 It is a schematic diagram of the structure of the distributed system provided in the embodiment of the present application. In the technical solution of the embodiment of the present application, data acquisition adopts a fast filtering algorithm, and combines the control architecture composed of FPGA+ARM to finally realize AD acquisition and algorithm processing, and the estimated flow time is 20~30us. At the same time, the software system adopts a distributed system to reduce the degree of coupling between system tasks. Figure 5, the system functions are divided into the following tasks: initialization task, data receiving task, data sending task, signal output task and signal acquisition task. Among them, the functions corresponding to the initialization task include: interface status initialization, bus and interface initialization, test parameter initialization and test judgment initialization. The functions of the data receiving task include: the optical fiber interface receives messages from each terminal and the Ethernet bus receives messages from each terminal. Among them, the functions of the data sending task include: the optical fiber interface sends instructions and data to each terminal, and the Ethernet male sends control instructions to each terminal. Among them, the functions of the signal output task include: 4-20mA current output and relay output. Among them, the functions of the signal acquisition task include: switch input, switch disconnection detection, 4-20mA signal acquisition, 4-20mA output signal acquisition and relay output acquisition. Among them, the implementation methods corresponding to the initialization task, data receiving task, data sending task, signal output task and signal acquisition task are: software parameter configuration, bus interface communication, bus interface communication, IO output and signal acquisition.

[0093] Figure 6 Schematic diagram of the circuit principle of the relay provided in the embodiment of the present application. For example, in the scheme of the embodiment of the present application, in the signal output design, the hardware uses a high-speed relay for output, which effectively reduces the action time of the relay and thus improves the response time of the system. For example, please refer to Figure 6 The principle of the high-speed relay is: the logic level (such as high level) is output through the output port of the FPGA, and the high level drives the high-speed relay output through the first transistor Q1. The high-speed relay action time is less than or equal to 3ms. At the same time, an alternative relay is also set to make it redundant. Figure 6 The left side in the middle is the driving circuit part of the high-speed relay, wherein the second end of the first transistor Q1, namely DOUT1, is the output port of the FPGA, outputting a logic level (high level or low level) to drive the high-speed relay (HFD42) through the first transistor Q1 circuit. Figure 6 The right side is the output circuit of the high-speed relay. Among them, DDOUT1 of the output circuit is connected to DDOUT1 of the drive circuit. The logic level of the FPGA drives the high-speed relay after passing through the drive circuit, and then outputs the switch value of OUT1+ and OUT1-.

[0094] Among them, the high-speed relay adopts a single-coil magnetic latching type to ensure that the relay will not jitter due to signal interference. The selected relay has a pair of interactive normally open and normally closed contacts, which can monitor the working status of the normally open contact by sampling the normally closed contact status.

[0095] Figure 7It is a schematic diagram of the circuit structure of the switch quantity signal acquisition and detection provided in the embodiment of the present application. In the technical scheme of the embodiment of the present application, the switch quantity input and fault diagnosis are set in the hardware setting as follows: each switch quantity input adopts 2 sets of optocoupler input circuits for acquisition, and by adjusting the resistance value of the input circuit, different optocoupler input induced currents in the three states of high, low and off can be generated to control the on and off of the optocoupler, thereby judging the state of the switch quantity. Among them, each optocoupler realizes 2-way isolated acquisition, one for the acquisition of switch quantity input, and the other for line break detection. At the same time, the switch quantity input signal is in common positive input mode.

[0096] See also Figure 7 , VIN8 is the power supply port of FPGA, Q2 is the second transistor, Q3 is the third transistor, D1 is the first diode, and D2 is the second diode. Among them, the second transistor Q2 through the first diode D1 and other matching resistors, and the third transistor Q3 through the second diode D2 and other matching resistors together constitute the driving circuit of the isolation optocoupler. Among them, AIN8 and BIN8 correspond to the output INPUT ports of the FPGA for 2-way AD acquisition respectively, and the control chip judges the on-off state of the current switch quantity through the level state sensed by these two INPUT ports. Among them, U1 is an isolation optocoupler (for example, ALP620 isolation optocoupler can be used), which is used to realize the isolated acquisition of 2-way switch quantities. ADL8 and BDL8 are 2-way acquisition points, corresponding to two optocoupler input circuits respectively, and are isolated from each other.

[0097] Figure 8 is a flow chart of a power matching method for a ship power grid system provided in an embodiment of the present application. Correspondingly, an embodiment of the present application also provides a power matching method for a ship power grid system, please refer to Figure 8 , the method comprises the following steps:

[0098] Step 110: collect the voltage of the busbar and the current of the load branch of the ship power grid system through the analog quantity collection module.

[0099] Step 120: Use a preset filtering algorithm to filter the voltage of the bus and the current of the load branch.

[0100] Among them, the preset filtering algorithm is used to filter the bus voltage and the current of the load branch, which is conducive to improving the rapid response of the current load rate of the subsequent ship power grid system, thereby improving the rapid response capability and reliability of the entire system.

[0101] Among them, the preset filtering algorithm includes: sampling the target analog quantity acquisition channel for a preset number of times, and continuously collecting a preset number of sampling points each time; calculating the average value of the preset number of sampling points for each sampling, and recording it as the first average value; screening and eliminating the maximum and minimum values ​​in the first average value sampled for the preset number of sampling times; calculating the average value of the first average value sampled for the preset number of sampling times after eliminating the maximum and minimum values, and recording it as the second average value.

[0102] The target analog acquisition channel is a specific analog quantity acquisition channel, which can be set according to actual conditions and is not specifically limited here.

[0103] The preset number of sampling times is the number of sampling times actually required, and its specific value can be set according to the actual situation, and is not specifically limited here.

[0104] The preset number is the number of sampling points collected each time, and its specific value can be set according to actual conditions, and is not specifically limited here.

[0105] Due to the complex environment and severe electromagnetic interference of the ship's DC power grid, the 4-20mA signal collected by the analog acquisition module cannot be directly used for the control strategy of the calculation module, and filtering is required. Specifically, by sampling the target analog acquisition channel multiple times, and calculating the average value of all sampling points for each sampling (i.e., the first average value), and removing the maximum and minimum values ​​from all the average values, and then calculating the average value of all the remaining first average values, the second average value is obtained, thereby removing noise and unnecessary disturbances, improving the quality of voltage and current signals, thereby improving the calculation response speed of subsequent load rates, and thus improving the responsiveness of the system.

[0106] In some embodiments, the second average value is calculated as:

[0107]

[0108] x(K)=(x(1)+x(2)+......+x(M)) / M

[0109] P=max{x(K)+(K-1)+(K-2)+......+x(KN)}

[0110] Q=min{x(K)+(K-1)+(K-2)+......+x(KN)}

[0111] in, is the second average value; N is the preset sampling number; M is the preset number; x(i) is the first average value of the i-th sampling; P is the maximum value of the first average value sampled at the preset sampling number; Q is the minimum value of the first average value sampled at the preset sampling number; x(K) is the average value of the M sampling points collected at time K.

[0112] The filtering algorithm provided in the embodiment of the present application can be applied to the filtering algorithm of the complex working conditions of the ship power grid system, and meet the performance index of the rapid response of the electric propulsion system. For example, taking a certain analog channel as an example, the filtering process is as follows:

[0113] First, for a certain analog channel, M points are collected continuously and the average value is calculated.

[0114] x(K)=(x(1)+x(2)+......+x(M)) / M

[0115] Then, find the maximum and minimum values ​​of x(K) and the average value of the previous N collected data. That is:

[0116] P=max{x(K)+(K-1)+(K-2)+......+x(KN)}

[0117] Q=min{x(K)+(K-1)+(K-2)+......+x(KN)}

[0118] Secondly, after removing the maximum and minimum values ​​of x(K) and the average values ​​of the previous N collections, find the average value of the remaining N-1 values, that is:

[0119]

[0120] Finally, The data is sent to the calculation module for subsequent load rate calculation. When the data is collected next time, the system returns to the first step and repeats the above process.

[0121] The filtering algorithm provided by the present application combines the advantages of sliding window algorithm and trimming average on the traditional average filtering algorithm, and proposes a comprehensive filtering algorithm with high efficiency, easy program implementation and fast response time, which can better adapt to the complex medium voltage DC ship power system. The algorithm has the following advantages: First, real-time response. The filtering algorithm of the present application can quickly respond to new data. When a new data point arrives, the old data is removed from the time window, and the new data point is included in the filtering algorithm, so it can respond to data in real time. (For example, the first N data collections at time K, where N is the time window). Second, the computational complexity is low. Compared with some complex time series filtering, the filtering algorithm of the present application does not introduce a large number of complex calculations, so it is more convenient for embedded systems to implement and the cost is also low. Third, it has high flexibility and can balance short-term fluctuations and smoothing effects by adjusting the length of the time window. Fourth, the filtering effect is good, and the filtering effect on some outliers and slight fluctuations is better than that of single average filtering and sliding window averaging.

[0122] Step 130: Determine the current load rate of the ship power grid system according to the filtered voltage and current.

[0123] In some embodiments, determining the current load rate of the ship power grid system based on the filtered voltage and current includes: calculating the real-time power of the first category of loads in the ship power grid system based on the filtered voltage and current; determining the maximum power of the second category of loads in the ship power grid system and the rated power of the generator set in the ship power grid system; calculating the current load rate of the ship power grid system based on the real-time power of the first category of loads, the maximum power of the second category of loads and the rated power of the generator set.

[0124] The first type of load is a common load, and the second type of load is a special load, wherein the special load is, for example, a special load such as a pulse load that requires maximum power to be reserved.

[0125] In some embodiments, the current load rate is calculated as:

[0126]

[0127] Among them, P i is the maximum power of m second-class loads, P j is the real-time power of n first-class loads, P k is the rated power of k generator sets.

[0128] The calculation formula of the real-time power of each load is:

[0129] P0=UI, where P0 is the real-time power of each load, U is the voltage of the bus after filtering, and I is the current of the load branch after filtering.

[0130] This application traverses the following Figure 1 The on / off status of each load in the topology shown is used to determine the current network units and load conditions, that is, the current system network topology status. Figure 1 , the calculation process of the current load rate is as follows: Assume that the current load rate of the power supply area where LM1 is located needs to be calculated and output through analog quantity. First, locate the busbar corresponding to the inverter of the tandem propulsion motor LM1 to be the 2# busbar. Then, determine whether the output circuit breaker QG3 corresponding to the diesel generator set DG3 on the 2# busbar is closed. If QG3 is closed, then P in the calculation formula of the current load rate k is the rated power of DG3. Next, determine whether the circuit breakers QS1 and QS2 corresponding to the special load on busbar 2# are closed at the same time. If the circuit breakers QS1 and QS2 are closed at the same time, then P i is the maximum power of 1# special load. After the equipment on 2# busbar (including generator sets for power supply and loads for power extraction) has been traversed and judged, it is determined whether QF1 is closed. If QF1 is closed, the equipment status of 1# busbar belonging to the previous power station is determined. If QF1 is open, it is determined whether QF3 is closed. If QF3 is closed, the equipment status of 1# busbar is determined. Among them, the network status of the equipment on 1# busbar and the corresponding power calculation rules are the same as those of 2# busbar, that is, if the outlet circuit breaker of the generator set on the corresponding busbar is closed, then P k For the current P k Add the rated power of the generator set on the current busbar. Special loads and ordinary loads are similar. If there is a generator on the current busbar, the corresponding P i and P j Increase in sequence. After traversing the situation of the front power station (the power station where LM1 is located) in sequence, start to judge the closing status of the left bus tie switches CS3 and CS4. If CS3 and CS4 are closed at the same time, it means that the front power station and the rear power station are in a networked operation state at this time, then starting from bus 5#, traverse the equipment conditions of bus 5#, bus 6#, bus 7# and bus 8# in sequence. Among them, the judgment method and calculation rules of bus 5#, bus 6#, bus 7# and bus 8# are similar to those of the front power station, and will not be repeated here. If CS3 and CS4 are not closed at the same time, it means that the front and rear power stations are in an off-grid operation state at this time. For LM1, it is only necessary to calculate the on-grid equipment status of the power station (ie, the front power station). The load rate calculation of the remaining power supply areas is similar to that of LM1, and will not be repeated here.

[0131] Step 140: adjust the output power of the tandem propulsion motor according to the current load rate of the ship's power grid system.

[0132] Among them, the ship power grid system also includes a switch output module.

[0133] Among them, the output power of the tandem propulsion motor is adjusted according to the current load rate of the ship's power grid system, including: when the current load rate of the ship's power grid system is greater than or equal to a first preset load rate, a fast power limiting signal is output to the frequency converter of the tandem propulsion motor through the switch output module; when the current load rate of the ship's power grid system is greater than or equal to a second preset load rate, an emergency power limiting signal is output to the frequency converter of the tandem propulsion motor through the switch output module.

[0134] The first preset load rate is smaller than the second preset load rate.

[0135] Exemplarily, the first preset load rate is 120%, and the second preset load rate is 150%.

[0136] Specifically, the load rate of the grid-connected generator set in the power supply area where the tandem electric propulsion device is located is obtained by the real-time calculation module of the analog output module and is output to the tandem propulsion motor in real time to implement dynamic power limitation. When the load rate exceeds the long-delay tripping threshold value of the generator set outlet circuit breaker (i.e., the load rate is greater than or equal to 120%), the switch output module outputs the switch signal "fast power limitation" to the propulsion inverter within 10ms, and the inverter performs fast power limitation to avoid overload and shutdown of the grid-connected generator set. When the load rate is greater than the short-delay tripping threshold value of the generator set outlet circuit breaker (i.e., the load rate is greater than or equal to 150%), the switch output module outputs the switch signal "emergency power limitation" to the propulsion inverter, and the inverter performs emergency power limitation to avoid overload and shutdown of the grid-connected generator set, thereby ensuring reliable power distribution of the system and improving the reliability of the system.

[0137] Step 150: Identify and locate the fault of the ship's power grid system.

[0138] Among them, the ship power grid system includes a front power station and a rear power station; the front power station and the rear power station are respectively provided with two power matching units; and the two power matching units of the front power station are redundant to each other, and the two power matching units of the rear power station are redundant to each other; the power matching unit at least includes a communication module and a fiber optic ring network.

[0139] Among them, the faults of the ship power grid system are identified and located, including: when a single fault occurs in only one of the redundant power matching units, the collection data of the normal power matching unit is obtained through the optical fiber ring network; when a single fault occurs in the redundant power matching units at the same time, the comprehensive fault is reported to the monitoring network through the communication module; when a single fault occurs in only one of the redundant power matching units, and the optical fiber ring networks corresponding to the redundant power matching units fail at the same time, the comprehensive fault is reported to the monitoring network through the communication module.

[0140] The power matching unit also includes: a switch quantity acquisition module, an analog quantity acquisition module and a calculation module. A single fault includes: a switch quantity acquisition module disconnection fault, an analog quantity acquisition module disconnection fault, a calculation module downtime fault and at least one of a communication fault. A comprehensive fault includes an incomplete data calculation fault and a power matching unit fault.

[0141] Fig. 9 is a schematic diagram of the fault type provided in the embodiment of this application. Fig. 9 ,The fault judgment types of the fault identification module include: analog quantity acquisition module disconnection fault, switch quantity acquisition module disconnection fault, computing module CPU crash fault, communication fault, data calculation incomplete fault and power matching unit fault.

[0142] In some embodiments, the identification of single faults and combined faults includes: when the current value of the analog quantity collected by the analog quantity acquisition module is less than the preset current, it is determined that the analog quantity acquisition module has a disconnection fault; when the disconnection detection hardware circuit of the switch quantity acquisition module feedbacks the disconnection condition of the switch quantity as valid, it is determined that the switch quantity acquisition module has a disconnection fault; when the central processing unit of the computing module has no heartbeat, it is determined that the computing module has a downtime fault; when the analog quantity data and / or the switch quantity data of the power matching unit are abnormal due to a single fault, it is determined that it is an incomplete data calculation fault; when at least one of the incomplete data calculation fault and the computing module downtime fault occurs, it is determined that the power matching unit has a fault.

[0143] Exemplarily, the preset current is 2 mA, and may also be other values, which can be set according to actual conditions and are not specifically limited here.

[0144] Exemplarily, the fault judgment strategy specifically includes: when the value of the collected 4-20mA analog quantity is less than 2mA, it is judged that the analog quantity acquisition module is disconnected. When the feedback result of the switch quantity disconnection detection hardware circuit of the switch quantity acquisition module is valid, it is judged that the switch quantity acquisition module is disconnected. When the CPU of the calculation module has no heartbeat, it is judged that the calculation module CPU is down. When the analog quantity and switch quantity data calculated by the power matching unit are abnormal due to the analog quantity acquisition module disconnection fault, the switch quantity acquisition module disconnection fault, and the calculation module CPU downtime fault, it is judged as an incomplete data calculation fault. When an incomplete data calculation fault and a calculation module CPU downtime fault occur, it is judged as a power matching unit module fault, and the fault relay is activated.

[0145] In the technical solution of the embodiment of the present application, the working principle of the power matching method of the ship power grid system is as follows: Figure 8First, the voltage of the busbar and the current of the load branch of the ship power grid system are collected through the analog quantity acquisition module. Then, the preset filtering algorithm is used to filter the voltage of the busbar and the current of the load branch. Secondly, the current load rate of the ship power grid system is determined according to the voltage and current after filtering. Finally, the output power of the series shaft propulsion motor is adjusted according to the current load rate of the ship power grid system, and the fault of the ship power grid system is identified and located. Therefore, the real-time load rate of the ship power grid system can be calculated by this method to adjust the output power of the system series shaft propulsion motor and realize the power matching of the ship power grid system. And the system fault is identified and located, the system fault is discovered in time, the reliable operation of the power matching is guaranteed, and the reliability of the system is improved. And before the load rate calculation, the voltage of the busbar and the current of the load branch are filtered, which can improve the responsiveness of the power matching, thereby improving the responsiveness and reliability of the entire system.

[0146] Compared with the related technologies, the power matching method of the ship power grid system provided by this application has the following beneficial effects: This application provides a high-reliability medium-voltage DC integrated electric tandem propulsion motor power matching method, which can fully consider the fast response time performance requirements of the tandem propulsion system for fast power limitation and emergency power limitation. In addition, this application adopts a dual-redundancy strategy of hardware and software under different faults to improve fault tolerance. The specific advantages are as follows:

[0147] First, in terms of hardware: based on the configuration of the series-shaft motor, the front and rear power stations of the ship's power grid system are cross-redundantly configured with power matching units in physical locations.

[0148] Second, in terms of interfaces: the main-backup power matching units of the front and rear power stations use optical fiber communication. On the one hand, it realizes the data redundancy backup function when a module fails, and on the other hand, it also improves the signal anti-interference performance.

[0149] Third, in terms of software: a fault identification module was designed to extract and locate the characteristics of different types of faults, improving the reliability of signal output. A digital filtering algorithm was proposed to improve the calculation accuracy of dynamic power limitation.

[0150] Fourth, in terms of functional design: First, it has the function of automatically identifying the topology of the ship's power grid system. Then, according to the identified topology of the ship's power grid system, the power distribution mode of the tandem propulsion motor is automatically switched, that is, when the power matching unit identifies that the power supply area where the two tandem propulsion motors are located is connected to the network, the power distribution ratio sent to the propulsion inverter is evenly divided; when the power matching unit is connected to the power supply area where the two tandem propulsion motors are located, the power distribution ratio sent to the propulsion inverter by the power matching unit is proportionally distributed with reference to the available power of each power station. Secondly, when the front and rear power stations are connected to the network, the power setting of the tandem propulsion motor is distributed in equal proportion.

[0151] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0152] The above is a detailed introduction to the ship power grid system and its power matching method provided in the embodiments of the present application, and the principles and implementation methods of the present application are explained by using specific examples. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​the present application; ordinary technicians in this field should understand that: they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A power matching method for a ship power grid system, characterized in that: Applied to the ship power grid system; The ship power grid system comprises: a series shaft propulsion motor, an analog quantity acquisition module, a bus bar and a load branch; The method comprises: The analog quantity acquisition module is used to acquire the voltage of the busbar and the current of the load branch of the ship power grid system; Using a preset filtering algorithm to filter the voltage of the bus and the current of the load branch, and determining the current load rate of the ship power grid system according to the filtered voltage and current; The output power of the tandem-shaft propulsion motor is adjusted according to the current load rate of the ship's power grid system; and the fault of the ship's power grid system is identified and located.

2. The power matching method of a ship power grid system according to claim 1, characterized in that: The preset filtering algorithm includes: The target analog quantity acquisition channel is sampled for a preset number of times, and each sampling continuously collects a preset number of sampling points; Calculate the average value of the preset number of sampling points for each sampling, and record it as a first average value; Filter and eliminate the maximum and minimum values ​​in the first average values ​​sampled at the preset sampling times; The average of the first average values ​​sampled at a preset number of sampling times after excluding the maximum value and the minimum value is calculated and recorded as the second average value.

3. The power matching method of a ship power grid system according to claim 2, characterized in that: The calculation formula of the second average value is: x(K)=(x(1)+x(2)+......+x(M)) / M P=max{x(K)+x(K-1)+x(K-2)+......+x(KN)} Q=min{x(K)+x(K-1)+x(K-2)+......+x(KN)} in, is the second average value; N is the preset sampling number; M is the preset number; x(i) is the first average value of the i-th sampling; P is the maximum value of the first average value sampled at the preset sampling number; Q is the minimum value of the first average value sampled at the preset sampling number; x(K) is the average value of the M sampling points collected at time K.

4. The power matching method of a ship power grid system according to claim 1, characterized in that: The determining the current load rate of the ship power grid system according to the filtered voltage and current includes: Calculate the real-time power of the first type of load in the ship power grid system according to the filtered voltage and current; Determining the maximum power of the second type of load in the ship power grid system and the rated power of the generator set in the ship power grid system; The current load rate of the ship power grid system is calculated according to the real-time power of the first type of load, the maximum power of the second type of load and the rated power of the generator set.

5. The power matching method of a ship power grid system according to claim 4, characterized in that: The calculation formula of the current load rate is: Among them, P i is the maximum power of m second-class loads, P j is the real-time power of n first-class loads, P k is the rated power of k generator sets.

6. The power matching method of a ship power grid system according to claim 1, characterized in that: The ship power grid system further includes a switch output module; the output power of the tandem propulsion motor is adjusted according to the current load rate of the ship power grid system, including: When the current load rate of the ship power grid system is greater than or equal to a first preset load rate, outputting a fast power limiting signal to the frequency converter of the tandem shaft propulsion motor through the switch output module; When the current load rate of the ship power grid system is greater than or equal to a second preset load rate, an emergency power limiting signal is output to the frequency converter of the tandem shaft propulsion motor through the switch output module.

7. The power matching method of a ship power grid system according to claim 6, characterized in that: The first preset load rate is less than the second preset load rate.

8. The power matching method of a ship power grid system according to claim 1, characterized in that: The ship power grid system includes a front power station and a rear power station; the front power station and the rear power station are respectively provided with two power matching units; and the two power matching units of the front power station are mutually redundant, and the two power matching units of the rear power station are mutually redundant; The power matching unit at least includes a communication module and an optical fiber ring network; The identifying and locating the fault of the ship power grid system includes: When only one of the redundant power matching units has a single fault, the collected data of the normal power matching unit is obtained through the optical fiber ring network; When a single fault occurs in the redundant power matching units at the same time, the comprehensive fault is reported to the monitoring network through the communication module; When only one of the mutually redundant power matching units has a single fault, and the optical fiber ring networks corresponding to the mutually redundant power matching units have faults at the same time, the comprehensive fault is reported to the monitoring network through the communication module.

9. The power matching method of a ship power grid system according to claim 7, characterized in that: The power matching unit further includes: a switch quantity acquisition module, the analog quantity acquisition module and a calculation module; The single fault includes: at least one of: a disconnection fault of the switch quantity acquisition module, a disconnection fault of the analog quantity acquisition module, a downtime fault of the calculation module, and a communication fault; The comprehensive fault includes a data calculation incomplete fault and a power matching unit fault.

10. The power matching method of a ship power grid system according to claim 8, characterized in that: The identification of the single fault and the combined fault includes: When the current value of the analog quantity collected by the analog quantity acquisition module is less than the preset current, it is determined that the analog quantity acquisition module is disconnected; When the feedback result of the disconnection detection hardware circuit of the switch quantity acquisition module on the disconnection of the switch quantity is valid, it is determined that the switch quantity acquisition module has a disconnection fault; When the central processing unit of the computing module has no heartbeat, it is determined that the computing module is down; When the analog quantity data and / or the switch quantity data of the power matching unit are abnormal due to the single fault, it is determined to be the data calculation incomplete fault; When at least one of the data calculation incomplete failure and the calculation module downtime failure occurs, it is determined that the power matching unit has a failure.

11. A ship power grid system, characterized in that: include: Serial shaft propulsion motor, analog quantity acquisition module, bus bar, load branch, filter module, calculation module, power regulation module and fault identification module; The analog quantity acquisition module is used to collect the voltage of the busbar and the current of the load branch of the ship power grid system; The filtering module is used to filter the voltage of the bus and the current of the load branch using a preset filtering algorithm; The calculation module is used to determine the current load rate of the ship power grid system according to the voltage and current after filtering; The power regulation module is used to regulate the output power of the tandem propulsion motor according to the current load rate of the ship power grid system; The fault identification module is used to identify and locate faults in the ship power grid system.

12. The ship power grid system according to claim 11, characterized in that: It also includes a front power station and a rear power station; the front power station and the rear power station are respectively provided with two power matching units; and the two power matching units of the front power station are mutually redundant, and the two power matching units of the rear power station are mutually redundant; the power matching unit at least includes a communication module and an optical fiber ring network; The fault identification module is also used for: When only one of the redundant power matching units has a single fault, the collected data of the normal power matching unit is obtained through the optical fiber ring network; When a single fault occurs in the redundant power matching units at the same time, the comprehensive fault is reported to the monitoring network through the communication module; When only one of the mutually redundant power matching units has a single fault, and the optical fiber ring networks corresponding to the mutually redundant power matching units have faults at the same time, the comprehensive fault is reported to the monitoring network through the communication module.

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