Control method and system for cooperative starting of multiple main propulsion motors of electric propulsion ship

Abstract

The invention relates to the technical field of ship comprehensive power systems, in particular to a control method and system for cooperative starting of multiple main propulsion motors of an electric propulsion ship, the propulsion demand power of the ship is obtained in real time, the actual total output power of operated motors is monitored, and a machine increasing instruction is generated by comparing the propulsion demand power with the actual total output power and combining the power margin of a current operation unit; responding to the instruction, starting a process of circularly scanning the standby motor in sequence, and synchronously checking whether each motor meets a starting permission condition or not during scanning; when a motor meeting all conditions is scanned for the first time, a starting instruction is sent to the motor, scanning is stopped immediately, and therefore it is ensured that only one healthy standby motor is started each time. The technical problems of power grid impact, faulty unit false starting and unintelligent and unreliable starting process which are possibly caused by lack of comprehensive judgment on the real-time state of the power grid and the equipment health degree during multi-machine starting are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship integrated power system, and particularly relates to a control method and system for coordinated starting of multiple main propulsion motors of an electrically propelled ship. BACKGROUND

[0002] The ship electric propulsion system is the core power system of modern high-tech ships (such as research ships, liquefied natural gas ships, luxury cruise ships, etc.). It realizes mechanical decoupling of the prime mover (such as a diesel engine, a gas turbine) and the propeller through the power network, which brings significant advantages such as flexible layout, economic and environmental protection, excellent control, high reliability, etc. The core of the system includes a generator set, a main distribution board, a frequency converter and a propulsion motor. With the development of large-scale and high-power ships, using multiple medium-power propulsion motors in parallel to replace a single large motor has become a mainstream technical solution. This configuration can realize power redundancy, optimize energy efficiency throughout the voyage, and avoid the technical challenges of a single super large motor.

[0003] However, the parallel operation of multiple machines also brings complex technical challenges in system starting and fault management. The coordinated starting of multiple main propulsion motors is particularly critical. The ship power station has limited capacity, and a large-capacity propulsion motor will generate a huge starting current in an instant, causing voltage drop. If multiple motors start at the same time, the current superposition effect may cause the voltage drop to exceed the allowed range (usually 10%-15%), endangering sensitive equipment and even causing the entire ship to lose power. Therefore, the multiple main propulsion motors must be started in an orderly manner. In addition, when a propulsion motor or frequency converter is detected to be faulty, the system needs to automatically skip the faulty unit and select a healthy unit to operate, which is another core requirement to ensure system reliability.

[0004] Currently, the traditional coordinated starting strategy has obvious limitations: first, it lacks global optimization and fails to fully consider the real-time carrying capacity of the power grid, which may exacerbate voltage fluctuations; second, it ignores the device state and does not equally consider the historical running time, temperature rise and the presence of faulty units, which is not conducive to the service life of the equipment and the overall reliability of the system. Therefore, in the face of the trend of ship electric propulsion systems towards multiple motors, high power and intelligentization, how to design an intelligent coordinated starting control method and system that can integrate the real-time state of the power grid, operational requirements and equipment health, to ensure the stability of the power grid, and to realize the optimization of the starting process in terms of speed and reliability, and to significantly improve the continuous operation capability of the system under fault conditions, has become a key technical problem to be solved in the field. SUMMARY

[0005] The purpose of the present application is to provide a control method and system for the coordinated starting of multiple main propulsion motors of an electrically propelled ship, which solves the problems of high risk of power grid impact, inability of faulty units to automatically avoid, and unintelligent and unreliable starting process caused by the lack of comprehensive judgment of the real-time state of the power grid and the health degree of the equipment during the starting of multiple main propulsion motors in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides a control method for the coordinated starting of multiple main propulsion motors of an electrically propelled ship, comprising the following steps: real-time acquisition of the propulsion demand power of the ship and monitoring of the actual total output power of the currently running multiple main propulsion motors; comparison of the demand power with the actual total output power and comprehensive judgment in combination with the total available power margin of the currently running units, generation of an increase unit instruction when it is determined that an increase unit is needed; in response to the increase unit instruction, starting of a process of sequentially and cyclically scanning all standby main propulsion motors; in the process for each scanned standby main propulsion motor, synchronous checking of a set of starting permission conditions, the starting permission conditions including that the motor is being polled, in a shutdown standby state, in a healthy state without faults, and the system is in an automatic mode; when it is first checked that a standby main propulsion motor meets all the starting permission conditions, a starting instruction is issued to the motor and the current cyclic scanning process is immediately terminated.

[0007] wherein the real-time acquisition of the propulsion demand power of the ship and the monitoring of the actual total output power of the currently running multiple main propulsion motors specifically comprises: the demand power signal is estimated based on the propeller speed set by the bell handle according to the cubic proportional relationship between the propeller absorbed power and the speed.

[0008] wherein the comparison of the demand power with the actual total output power and the comprehensive judgment in combination with the total available power margin of the currently running units, the generation of an increase unit instruction when it is determined that an increase unit is needed, specifically comprises: the judgment logic for generating the increase unit instruction is that the demand power is continuously greater than the actual total output power, and the difference exceeds the total available power margin of the currently running units.

[0009] wherein, in response to the increase unit instruction, the process of sequentially and cyclically scanning all standby main propulsion motors is started, specifically comprising: starting the cyclic scanning process specifically comprises that the increase unit instruction triggers a clock pulse generated by an oscillation circuit, and the clock pulse is converted into multiple polling signals output in sequence and cyclically by a pulse distributor.

[0010] The termination of the current cycle scanning process is achieved by feeding the start instruction outputted successfully to a reset logic circuit, and then generating a signal to reset the oscillation circuit.

[0011] In the process for each standby main propulsion motor being scanned, a group of start permission conditions are synchronously checked, including that the motor is being polled, in a shutdown standby state, in a fault-free healthy state, and the system is in an automatic mode, specifically including: The judgment of the fault-free healthy state is based on that the motor has no fault alarm and its temperature rise does not exceed a preset safety threshold.

[0012] In the process for each standby main propulsion motor being scanned, a group of start permission conditions are synchronously checked, including that the motor is being polled, in a shutdown standby state, in a fault-free healthy state, and the system is in an automatic mode, specifically including: The checking of the group of start permission conditions is completed by logical AND operation, and when all the input signals corresponding to the conditions are simultaneously valid, it is determined that the start is allowed.

[0013] The AND gate circuit is used to receive the input signals, and its output is directly used as the start instruction.

[0014] The control system for coordinated start of multiple main propulsion motors of an electrically propelled ship includes a power decision module and a coordinated start logic module. The power decision module is configured to generate an increase machine instruction according to a comparison result of a demand power and an actual total output power of the running motors, and a power margin of the current running unit. The coordinated start logic module is connected to the power decision module and includes: A sequence controller is configured to generate a cyclic polling signal sequence. A plurality of parallel motor control channels, each corresponding to a main propulsion motor, are configured to receive the polling signal, the running state signal, the health state signal and the control mode signal of the corresponding motor, and output a start instruction. An interlock feedback unit is configured to send a lock signal to the sequence controller to interrupt the current polling sequence after the start instruction is outputted by any of the motor control channels.

[0015] The application discloses a control method and system for cooperative starting of multiple main propulsion motors of an electrically propelled ship. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced.

[0017] Figure 1 is a unit starting flowchart of the first embodiment of the application.

[0018] Figure 2 is a multiple motor and multiple propeller model diagram of the first embodiment of the application.

[0019] Figure 3 is a unit number increasing instruction principle diagram of the first embodiment of the application.

[0020] Figure 4 is a cooperative starting control principle diagram of the first embodiment of the application.

[0021] Figure 5 is a step flowchart of the control method for cooperative starting of multiple main propulsion motors of an electrically propelled ship of the first embodiment of the application.

[0022] Figure 6 is a principle block diagram of the control system for cooperative starting of multiple main propulsion motors of an electrically propelled ship of the second embodiment of the application.

[0023] In the figure: 201-power decision module, 202-cooperative starting logic module, 203-sequence controller, 204-motor control channel, 205-interlock feedback unit. DETAILED DESCRIPTION

[0024] Embodiments of the present application are described below in detail, examples of which are shown in the accompanying drawings, the embodiments described below by reference to the drawings are exemplary, and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0025] The first embodiment of the present application is: Please refer to Figures 1 to 5 The present application provides a control method for cooperative starting of multiple main propulsion motors of an electrically propelled ship, comprising the following steps: S101: Real-time acquisition of the propulsion demand power of the ship, and monitoring of the actual total output power of the currently running multiple main propulsion motors; S102: Comparison of the demand power with the actual total output power, and comprehensive judgment in combination with the total available power margin of the current running unit, generation of an increase unit instruction when it is determined that the unit needs to be increased; S103: In response to the increase unit instruction, starting of a process of sequentially circulating scanning of all standby main propulsion motors; S104: In the process for each scanned standby main propulsion motor, a set of starting permission conditions are synchronously checked, the starting permission conditions including that the motor is being polled, in a shutdown standby state, in a fault-free healthy state, and the system is in an automatic mode; S105: When a standby main propulsion motor is first checked to satisfy all the starting permission conditions, a starting instruction is issued to the motor and the current circulating scanning process is immediately terminated.

[0026] Specifically, the present application is an integrated circuit, and proposes a control method for cooperative starting of multiple main propulsion motors based on an electrically propelled ship. Thus, the power grid impact is avoided, the propulsion continuity of the power system is maintained, the stability of the ship power grid and the power system is ensured, and the operation efficiency of the power system is improved. Most of the current electrically propelled ships adopt a multiple motor and multiple propeller driving mode, i.e., one motor drives one propeller, and 2-4 of them are more common, Figure 2 (a) is a double motor and double propeller type, Figure 2 (b) is a three motor and three propeller model.

[0027] To achieve the above object, the present application provides the following technical solutions: (1) Formation of an increase unit instruction: As Figure 2 When the ship needs to increase the propeller driving power due to the need for acceleration, resistance increase caused by severe sea conditions, etc., its electric propulsion system may need to increase the number of running units. The present application designs a principle diagram for increasing the number of units, as shown in Figure 3 .

[0028] Figure 3In this circuit, OR is an OR gate that receives speed signals from the control panel, central control room, and locomotive telegraph handle. K is an integrated operational amplifier circuit.

[0029] Once the command to increase the number of generators is issued, which main propulsion motor will be put into operation? (2) Coordinated start-up control: For multi-engine, multi-propeller ship electric propulsion systems, coordinated start-up control is required under various operating conditions. Firstly, when an additional engine command is issued, if there are more than two standby units, coordinated start-up is necessary. Secondly, when the ship sets sail, coordinated start-up is required to prevent excessive current from being generated and impacting the power grid due to the simultaneous start-up of multiple main propulsion motors.

[0030] Electric propulsion boats often use a combination of 2-4 motors and propellers. This invention focuses on a power propulsion system with 4 main propulsion motors and designs a coordinated starting scheme for it. Figure 4 In the diagram, FF is a trigger, SO is a thyristor oscillator circuit, CP is a pulse distributor, NG is a NOR gate, and ABCD represents four AND gates. The input X0 of the four AND gates comes from the CP pulse distributor; the input X1 signal comes from the stator voltage transformer of the main propulsion motor, representing the stator voltage signal. When there is voltage on the stator, X1 signal is 0; when there is no voltage on the stator, X1 signal is 1; the input X2 represents a blocking signal, which includes situations such as motor malfunction or excessive motor temperature rise. When there is a motor malfunction or the motor temperature rises above a threshold, X2 signal is 0; when there is no motor malfunction or the temperature rise is normal, X2 signal is 1; the input X3 represents the main propulsion motor control mode. X3 signal is 1 during automatic control and 0 during manual control. The outputs of the four AND gates control the starters of the four main propulsion motors M1-M4 respectively.

[0031] In practice: (1) Increase aircraft command: Figure 3 In this paper, to simplify the description of the objects, we assume that the main propulsion motors have the same model, rated power, and other parameters. Let the rated power of each main propulsion motor be... The number of main propulsion motors currently in operation is q. Using a power calculation module (such as the domestically produced Uni-Trend clamp-on power meter UT390C, or a combination of voltage and current transformers), the current total output power of the q units can be calculated. ( This represents the output power of the i-th main propulsion motor. A standard 0-5V DC voltage signal is obtained through a power transmitter (e.g., paired with a current transformer and a Changchen Instrument FPPF series three-phase power transmitter). ), and then the potential UB at point B in the figure can be obtained (i.e. The signal is sent to the inverting input terminal of the integrated operational amplifier circuit K via resistor R1.

[0032] According to Figure 3 The current propeller required to absorb the power, the estimated basis for the propeller to absorb the power P and its speed n is proportional to the third power, namely: (1) In formula (1), P represents the power absorbed by the propeller, n represents the speed of the propeller (at the same speed as the main propulsion motor, or fixed ratio). Therefore, the current state of the propeller can also be estimated by the bell handle speed setting value to absorb the power. Through the power transmitter, a 0-5V DC voltage signal is obtained, that is, the potential of point A , the potential Reflects the current propeller required to absorb the power, the signal is sent to the K in-phase input terminal through the electronic .

[0033] Figure 3 K is an integrated operational amplifier circuit, which amplifies the voltage difference from points A and B, and the output voltage is According to the principle of integrated operational amplifier circuit, the expression is as follows: (2) In formula (2), if >0, it means that the current propeller required to absorb the power is greater than the total power actually output by the q main propulsion motor.

[0034] Let: (3) In formula (3), represents the maximum total power that the q main propulsion motor can output, represents the total power actually output by the q main propulsion motor, represents the power that the q main propulsion motor can still output under the premise of no load. The is converted into a voltage signal through a power transmitter (the circuit principle before the operational amplifier circuit K is the same, which is omitted here), that is, the in the figure, when > That is, the machine command is issued.

[0035] (2) Cooperative start: Assume Figure 4 ​The main propulsion motor M1, M2 in the middle is in the running state, M3, M4 is in standby. If the propeller load increases at this time, the power system output power needs to be increased, that is, a main propulsion motor needs to be put into work, the S end of the flip-flop FF (optional model 74LS00) will receive the instruction to increase the machine (low level effective), so that FF output 1, Figure 4 The thyristor oscillator circuit (for example: MCR100-6 thyristor + 10kΩ resistor + CBB220.47μF / 100V capacitor + 2N2647 single transistor + current limiting resistor + 12V-24V power supply, etc.) SO oscillates, and the pulse distributor (for example, use chips CD4017, CD4014, etc.) CP Y3Y2Y1Y0 outputs 1000, 0100, 0010, 0001 signals.

[0036] 1) Pulse 1000 signal: When the first pulse output by the CP pulse distributor makes the Y3Y2Y1Y0 four pins 1000, that is, the 1 signal on the Y3 pin is sent to the X0 channel of the AND gate (optional CD4082B, 74LS21, etc.) A; The 0 signals of Y2Y1Y0 three pins are sent to the X0 channels of AND gates B, C, and D respectively. Although the X0 signal channel of the Y3 pin on the current CP sent to the AND gate A is a 1 signal, but since the current M1 is in the running state, the X1 channel signal representing the voltage signal is 0, that is, the output of the AND gate A is 0, which will not give the unit M1 start-up instruction.

[0037] 2) Pulse 0100: The principle is the same as pulse 1000, and the output of AND gate B is 0, which will not give the unit M2 start-up instruction.

[0038] 3) Pulse 0010: When the first pulse output by the CP pulse distributor makes the Y3Y2Y1Y0 four pins 0010, that is, the 1 signal on the Y1 pin is sent to the X0 channel of the AND gate C; The 0 signals of Y3Y2Y0 three pins are sent to the X0 channels of AND gates A, B, and D respectively. Make the 4 input signals of AND gate C all 1, output 1, start unit M3. When AND gate C outputs 1 signal to start unit M3, the signal is sent to NAND gate (optional CD4002B, 74HCT4002, etc.) NG, so that the output of NAND gate is 0 signal, which is sent to the reset end R of flip-flop FF, so that FF output 0, thyristor oscillator SO stop working. When the unit M3 is powered on, the stator end establishes voltage and starts, the input end X1 of the AND gate C will be 0, making the output of the AND gate C 0, making the output of the NAND gate NG 1 again, and the R end of the flip-flop FF jumps from the original 0 signal to the current 1 signal, preparing for the start of the next unit.

[0039] 4) Pulse 0001: When the pulse 0010 is issued to start the unit M3, the unit M3 is in a fault state, i.e. the signal of X2 of the AND gate C is 0, the command to start the unit M3 cannot be issued. The thyristor oscillator SO continues to oscillate, and the next pulse 0001 of the pulse distributor CP will start the unit M4.

[0040] Note: ① Figure 4 The number of the unit is arbitrarily assumed; ② The signal of the input X1 of the AND gate ABCD can be more than one, and the combination of voltage, current, speed or torque signals can be used.

[0041] Based on the principle of integrated circuits, by designing a comprehensive management algorithm that integrates real-time power grid evaluation, equipment state monitoring and task demand response, the optimization of the rapidness and reliability of the starting process of the standby unit of the main propulsion motor of the ship is realized under the premise of ensuring the stability of the power grid, and the continuous operation ability and intelligent level of the system under fault conditions are significantly improved, which provides theoretical support and technical basis for the design of the propulsion system of the new generation of intelligent ships.

[0042] The second embodiment of the application is: Based on the first embodiment, please refer to Figure 6 The control system for the multi-main-propulsion-motor cooperative starting of the electric ship of the embodiment comprises a power decision module 201 and a cooperative starting logic module 202.

[0043] For the specific embodiment, the power decision module 201 is used to generate an increase-unit command according to the comparison result of the demand power and the actual total output power of the running motor, and the power margin of the current running unit; The cooperative starting logic module 202 is connected to the power decision module 201 and comprises: A sequence controller 203 is used to generate a circulating polling signal sequence; A plurality of parallel motor control channels 204, each corresponding to one main propulsion motor, are used to receive the polling signal, the running state signal, the health state signal and the control mode signal of the corresponding motor, and output a starting command; An interlocking feedback unit 205 is used to send a locking signal to the sequence controller 203 to interrupt the current polling sequence after any of the motor control channels 204 outputs a starting command.

[0044] The control system of the electric ship multi-main propulsion motor cooperative starting of the embodiment is used. After the system is powered on, the power decision module 201 continuously monitors the propeller demand power set by the telegraph handle and the actual total output power of the multiple main propulsion motors that have been put into operation. Through comparison and power margin calculation, the machine increasing instruction is generated when it is determined that the power needs to be increased. The instruction triggers the start of the sequence controller 203 in the cooperative starting logic module 202, the sequence controller 203 triggers the built-in thyristor oscillation circuit to generate a pulse sequence, and generates a circulating polling signal through a pulse distributor. These polling signals are sent to each motor control channel 204 in parallel, each channel synchronously receives the running state feedback signal of the corresponding motor, the health state signal representing the fault and temperature rise, and the system automatic / manual control mode signal, and checks through the AND gate logic. When all input signals of a channel meet the valid conditions at the same time, the channel immediately outputs the starting instruction to drive the corresponding motor to start. At the same time, after the interlocking feedback unit 205 receives the starting instruction, it immediately sends a locking signal to the sequence controller 203, so that it is reset and stops the current polling, ensuring that only one motor starts at the same time. The system realizes intelligent decision and selection based on real-time power demand and equipment state through hardware logic, effectively avoids the impact of multiple machine starting on the power grid, and can automatically avoid faulty units, thereby significantly improving the reliability, speed and overall intelligence level of the system in the premise of ensuring the stability of the power grid.

[0045] The above only discloses one or more preferred embodiments of the application, and cannot limit the scope of the application. Those skilled in the art can understand that the implementation of all or part of the above-mentioned embodiments is still within the scope of the application.

Claims

1. A control method for the coordinated starting of multiple main propulsion motors in an electric propulsion vessel, characterized in that, Includes the following steps: The system can acquire the ship's propulsion power requirements in real time and monitor the actual total output power of the multiple main propulsion motors currently in operation. The required power is compared with the actual total output power, and a comprehensive judgment is made in combination with the total available power margin of the currently operating units. When it is determined that additional units need to be added, an additional unit instruction is generated. In response to the aforementioned booster command, a process of sequentially scanning all standby main propulsion motors is initiated; In the process for each scanned standby main propulsion motor, a set of start-up permission conditions are simultaneously verified. The start-up permission conditions include: the motor is being polled, it is in a standby state, it is in a fault-free healthy state, and the system is in automatic mode. When a standby main propulsion motor is found to meet all the aforementioned start-up permission conditions for the first time, a start-up command is issued to the motor and the current cyclic scanning process is immediately terminated.

2. The control method for coordinated starting of multiple main propulsion motors in an electric propulsion vessel as described in claim 1, characterized in that, The system acquires the ship's propulsion power requirements in real time and monitors the actual total output power of the multiple main propulsion motors currently in operation, specifically including: The required power signal is estimated based on the propeller speed set by the telegraph handle, according to the cubic relationship between the power absorbed by the propeller and the speed.

3. The control method for coordinated starting of multiple main propulsion motors in an electric propulsion vessel as described in claim 1, characterized in that, The required power is compared with the actual total output power, and a comprehensive judgment is made in conjunction with the total available power margin of the currently operating units. When it is determined that additional units are needed, an addition command is generated, specifically including: The judgment logic for generating the additional unit instruction is: the demand power is continuously greater than the actual total output power, and the difference exceeds the total available power margin of the currently operating unit.

4. The control method for coordinated starting of multiple main propulsion motors in an electric propulsion vessel as described in claim 1, characterized in that, In response to the aforementioned booster command, a process of sequentially scanning all standby main propulsion motors is initiated, specifically including: The specific steps for initiating the cyclic scanning process are as follows: the boost instruction triggers an oscillation circuit to generate a clock pulse, and the pulse distributor converts the clock pulse into multiple polling signals that are output sequentially and cyclically.

5. The control method for coordinated starting of multiple main propulsion motors in an electric propulsion vessel as described in claim 4, characterized in that, Terminating the current cyclic scanning process is achieved by feeding back the successfully output start command to a reset logic circuit, which in turn generates a signal to reset the oscillation circuit.

6. The control method for coordinated starting of multiple main propulsion motors in an electric propulsion vessel as described in claim 1, characterized in that, In the process for each scanned standby main propulsion motor, a set of start-up permission conditions are simultaneously verified. These conditions include: the motor is being polled, it is in a standby state, it is in a fault-free healthy state, and the system is in automatic mode. Specifically, these conditions include: The criteria for determining that the motor is in a fault-free and healthy state are that the motor has no fault alarm and its temperature rise does not exceed the preset safety threshold.

7. The control method for coordinated starting of multiple main propulsion motors in an electric propulsion vessel as described in claim 1, characterized in that, In the process for each scanned standby main propulsion motor, a set of start-up permission conditions are simultaneously verified. These conditions include: the motor is being polled, it is in a standby state, it is in a fault-free healthy state, and the system is in automatic mode. Specifically, these conditions include: The verification of the set of start-up permission conditions is completed through a logical AND operation. When the input signals corresponding to all conditions are valid at the same time, it is determined that start-up is allowed.

8. The control method for coordinated starting of multiple main propulsion motors in an electric propulsion vessel as described in claim 7, characterized in that, The input signal is received using an AND gate circuit, and its output is directly used as a start command.

9. A control system for the coordinated starting of multiple main propulsion motors in an electric propulsion vessel, used to implement the method as described in claim 1, characterized in that, Includes a power decision module and a cooperative start-up logic module; The power decision module is used to generate a generator addition command based on the comparison between the required power and the actual total output power of the running motors, as well as the power margin of the currently running units. The coordinated start-up logic module, connected to the power decision module, includes: Sequence controller, used to generate a cyclic polling signal sequence; Multiple parallel motor control channels, each corresponding to a main propulsion motor, are used to receive polling signals, the corresponding motor's operating status signals, health status signals, and control mode signals, and output start commands; An interlock feedback unit is used to send a locking signal to the sequence controller to interrupt the current polling sequence after any of the motor control channels outputs a start command.

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