Propulsion system, control program, and control method for vessel

Abstract

To provide a propulsion system, a control program, and a control method for a vessel capable of reducing environmental load while responding to propulsion force required in various situations in a vessel capable of driving a propulsion propeller either by an engine or a motor generator.SOLUTION: A propulsion system for a vessel: has a process circuit for a controller configured to be executed by switching between a first control mode and a second control mode; in the first control mode, drives a propulsion propeller by output of an engine when a vessel speed index value is a reference value or more and drives the propulsion propeller by output of a motor generator with the engine in a stopped state when the vessel speed index value is less than the reference value; and in the second control mode, drives the propulsion propeller by output of the engine by controlling to maintain the rotational number of the engine to a prescribed rotational number regardless of the vessel speed index value, and controls a power converter to generate power by the motor generator using excessive output of the engine.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a propulsion system, a control program, and a control method for a ship.

Background Art

[0002] There is known a ship capable of driving a propulsion propeller by either an engine or an electric generator. For example, Patent Document 1 below describes a control method in which an engine propulsion mode using only the driving force of the engine as the propulsion force of the ship and a hybrid propulsion mode using the driving forces of the engine and the electric generator as the propulsion force of the ship are selectively executed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a ship capable of driving a propulsion propeller by either an engine or an electric generator as in Patent Document 1 above, there is room for improvement in realizing a ship propulsion system with a low environmental load while coping with the propulsion force required in various situations.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a ship propulsion system, a control program, and a control method that can reduce the environmental load while coping with the propulsion force required in various situations in a ship capable of driving a propulsion propeller by either an engine or an electric generator.

Means for Solving the Problems

[0006] A propulsion system according to one aspect of the present disclosure includes an engine mechanically connected to a propulsion propeller, a motor generator mechanically connected to the engine, capable of generating electricity using the driving force of the engine, and capable of transmitting power to the propulsion propeller, a power converter electrically connected to the motor generator, and a controller for controlling the engine and the power converter based on a propulsion force command value. The propulsion system of a ship is characterized in that the controller includes a processing circuit, and the processing circuit is configured to be able to switch between and execute a first control mode and a second control mode. In the first control mode, a ship speed index value including the ship speed, the propulsion force command value, or a ship speed target value based on the propulsion force command value is obtained. When the ship speed index value is equal to or greater than a predetermined reference value, the engine is controlled to drive the propulsion propeller by the output of the engine. When the ship speed index value is less than the reference value, the power converter is controlled to drive the propulsion propeller by the output of the motor generator with the engine stopped. In the second control mode, regardless of the ship speed index value, the rotational speed of the engine is controlled to be maintained at a predetermined rotational speed, the propulsion propeller is driven by the output of the engine, and the power converter is controlled to generate electricity with the motor generator using the surplus output of the engine obtained by subtracting the propulsion force required to set the rotational speed of the engine to the predetermined rotational speed from the propulsion force command value.

[0007] A control program according to another aspect of the present disclosure is a control program for a vessel including an engine mechanically connected to a propulsion propeller, a motor-generator mechanically connected to the engine and capable of generating electricity using the driving force of the engine and transmitting power to the propulsion propeller, a power converter electrically connected to the motor-generator, and a controller that controls the engine and the power converter based on a propulsion force command value, wherein the control program causes the controller to acquire a vessel speed index value including a vessel speed, the propulsion force command value, or a vessel speed target value based on the propulsion force command value, and when the vessel speed index value is equal to or greater than a predetermined reference value, to generate power by using an output of the engine. The control mode is switched between a first control mode in which the engine is controlled to drive the propulsion propeller, and when the speed index value is less than the reference value, the power converter is controlled to drive the propulsion propeller with the output of the motor-generator while the engine is stopped, and a second control mode in which the engine speed is controlled to maintain a predetermined speed regardless of the ship speed index value, the propulsion propeller is driven with the output of the engine, and the power converter is controlled to generate electricity with the motor-generator using surplus output of the engine, calculated by subtracting the propulsion force required to make the engine speed the predetermined speed from the propulsion force command value.

[0008] A control method according to another aspect of the present disclosure is a control method for a vessel including an engine mechanically connected to a propulsion propeller, a motor-generator mechanically connected to the engine and capable of generating electricity using the driving force of the engine and transmitting power to the propulsion propeller, a power converter electrically connected to the motor-generator, and a controller that controls the engine and the power converter based on a propulsion force command value, the control method comprising: acquiring a vessel speed index value including a vessel speed, the propulsion force command value, or a vessel speed target value based on the propulsion force command value; and driving the propulsion propeller with an output from the engine when the vessel speed index value is equal to or greater than a predetermined reference value. and a second control mode in which the power converter is controlled to maintain the rotational speed of the engine at a predetermined rotational speed regardless of the ship speed index value, drive the propulsion propeller with the output of the engine, and generate electricity with the motor generator using surplus output of the engine, calculated by subtracting the propulsive force required to make the rotational speed of the engine the predetermined rotational speed from the propulsive force command value. [Effects of the Invention]

[0009] According to the present disclosure, in a vessel in which the propulsion propeller can be driven by either an engine or a motor-generator, it is possible to reduce the environmental load while responding to the propulsive force required in various situations. [Brief explanation of the drawings]

[0010]

Figure 1

Figure 2

[0011] Hereinafter, embodiments will be described in detail with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference numerals throughout all the drawings, and redundant descriptions thereof are omitted.

[0012] [Embodiment] FIG. 1 is a block diagram showing a schematic configuration of a propulsion system of a ship according to an embodiment of the present disclosure. The ship in this embodiment is a hybrid propulsion ship that can use an engine 3 and an electric generator 4 as power sources for driving a propulsion propeller 2.

[0013] The propulsion system 1 in this embodiment includes a propulsion propeller 2, an engine 3, an electric generator 4, and a first power converter 7. The propulsion propeller 2 is a variable pitch propeller configured to be able to change the blade angle according to a propulsion force command value.

[0014] The engine 3 is a gas engine that generates driving force using fuel including fuel gas obtained by vaporizing liquefied natural gas. Note that the engine 3 may be a gas dedicated combustion engine that exclusively burns fuel gas obtained by vaporizing liquefied natural gas, a dual fuel engine that can switch between combustion of fuel gas and liquid fuel such as heavy oil, or a diesel engine that uses liquid fuel as fuel.

[0015] The engine 3 and the electric generator 4 are mechanically connected to the propulsion propeller 2 via a speed reducer 5. The electric generator 4 is electrically connected to the first power converter 7. The first power converter 7 is interposed between the DC wiring 6 and the electric generator 4. The electric generator 4 can transmit power to the propulsion propeller 2 by generating power from the power supplied through the DC wiring 6. At this time, the first power converter 7 converts the DC voltage in the DC wiring 6 into an AC voltage and outputs it to the electric generator 4. Further, the electric generator 4 can also generate electricity using the driving force of the engine 3 and supply power to the DC wiring 6. At this time, the first power converter 7 converts the AC voltage generated by the electric generator 4 into a DC voltage and outputs it to the DC wiring 6.

[0016] Furthermore, a capacitor 9 is connected to the DC wiring 6. The capacitor 9 is a secondary battery, a capacitor, or the like, and may include a power converter such as a DC-DC converter that converts the DC voltage of the DC wiring 6 into a predetermined DC voltage. Also, an AC wiring 11 is connected to the DC wiring 6 via a second power converter 10. The second power converter 10 converts the DC voltage of the DC wiring 6 into an AC voltage and outputs it to the AC wiring 11, and converts the AC voltage of the AC wiring 11 into a DC voltage and outputs it to the DC wiring 6. Electrical equipment within the ship may be connected to the AC wiring 11 or the DC wiring 6.

[0017] According to such a propulsion system 1, the propulsion force of the ship can be generated cooperatively between the engine 3, which is a mechanical propulsion unit, and the motor generator 4, which is an electric propulsion unit. Also, according to the propulsion system 1, the surplus of the propulsion force generated by the engine 3 can be recovered as electric power by the motor generator 4 and supplied to the AC wiring 11 or stored in the capacitor 9.

[0018] The propulsion system 1 includes a controller 14. The controller 14 includes a processing circuit 15 that performs various signal processes. The processing circuit 15 has a computer such as a microcontroller, a personal computer, or a PLC (Programmable Logic Controller). More specifically, the processing circuit 15 includes a processor, a memory, and peripheral circuits. The processor includes, for example, a CPU or an MPU. The memory includes a ROM, a RAM, a register, a non-volatile storage, and the like. The peripheral circuits include input / output interfaces and the like. The controller 14 is connected to an operation input device 16 that operates the hybrid propulsion ship. The controller 14 may be connected to a monitor that displays the control state or a speaker that outputs sound.

[0019] Note that the functions of the elements disclosed in this specification can be executed using a circuit or processing circuit including a general-purpose processor, a dedicated processor, an integrated circuit, an ASIC (Application Specific Integrated Circuits), a conventional circuit, and / or a combination thereof configured or programmed to execute the disclosed functions. Since a processor includes transistors and other circuits, it is regarded as a processing circuit or a circuit. In this specification, a circuit, unit, means, or section is hardware that executes the listed functions or hardware programmed to execute the listed functions. The hardware may be the hardware disclosed in this specification or other known hardware programmed or configured to execute the listed functions. When the hardware is a processor considered to be a type of circuit, the circuit, unit, or means is a combination of hardware and software, and the software is used for the configuration of the hardware and / or the processor.

[0020] A control program for controlling a controlled object is stored in the memory of the controller 14. The controller 14 controls the controlled object based on the control program. The controlled objects of the controller 14 include the propulsion propeller 2, the engine 3, and the first power converter 7. The controller 14 may be configured as one controller that controls these components 2, 3, 7 or may be configured by two or more controllers. Further, the controller 14 may be configured to be able to control the capacitor 9, the second power converter 10, or a load connected to the AC wiring 11.

[0021] The controller 14 controls the blade angle of the propulsion propeller 2, the output of the engine 3, and the first power converter 7 based on the propulsion force command value Fo. The propulsion force command value Fo is input from the operation input device 16. The operation input device 16 can be constituted by, for example, an operation lever or an operation handle for operating the speed adjustment of the ship and the switching between forward and reverse. For example, the operation lever is configured such that the position where the maximum amount of operation in the first direction corresponds to the maximum ship speed on the forward side, the position where the maximum amount of operation in the second direction opposite to the first direction corresponds to the maximum ship speed on the reverse side, and the neutral position corresponds to a ship speed of 0.

[0022] The operation input device 16 generates a propulsion force command value Fo that is larger as the ship speed corresponding to the operation position of the operation lever is higher. The processing circuit 15 generates a blade angle target value Wo for the propulsion propeller 2 based on the propulsion force command value Fo. The processing circuit 15 generates a blade angle target value Wo such that the blade angle increases as the propulsion force command value Fo increases. For example, when the operation lever is in the position in the first direction, a blade angle target value Wo with a positive blade angle is generated, and when the operation lever is in the position in the second direction, a blade angle target value Wo with a negative blade angle is generated.

[0023] In addition, in the present embodiment, the propulsion system 1 includes a blade angle sensor 17 that detects the blade angle of the propulsion propeller 2. The controller 14 acquires the value detected by the blade angle sensor 17 and performs feedback control so that the blade angle of the propulsion propeller 2 becomes the blade angle target value Wo.

[0024] Furthermore, the controller 14 controls the rotational speed of the engine 3 according to the propulsion force command value Fo. The processing circuit 15 generates an engine rotational speed target value Eo from the propulsion force command value Fo. The controller 14 controls the engine 3 so that the rotational speed of the engine 3 maintains the engine rotational speed target value Eo.

[0025] Furthermore, the controller 14 controls the first power converter 7 in accordance with the power conversion command value. For example, when the propulsion force command value Fo is smaller than the engine speed target value Eo while the engine 3 is operating, the controller 14 controls the first power converter 7 to generate electricity by rotating the motor generator 4 with the power of the difference, and to supply the power generated by the motor generator 4 to the DC wiring 6. The power supplied from the first power converter 7 to the DC wiring 6 is supplied to the AC wiring 11 via the second power converter 10. The surplus power is supplied from the DC wiring 6 to the capacitor 9 and stored in the capacitor 9.

[0026] Furthermore, when the engine 3 is stopped, the controller 14 supplies the electric power stored in the capacitor 9 to the motor generator 4 and controls the first power converter 7 to transmit the output of the motor generator 4 to the propulsion propeller 2.

[0027] In this way, the controller 14 controls the operation or stop of the engine 3 in combination with the operation or power generation of the motor generator 4. In this embodiment, the processing circuit 15 of the controller 14 is configured to be able to switch between a first control mode and a second control mode.

[0028] 2 is a diagram showing the operating states of the engine, motor generator, and capacitor according to the boat speed index value in the first control mode and the second control mode of this embodiment. In the first control mode, the processing circuit 15 acquires the boat speed index value Vc and performs control according to the boat speed index value Vc. The boat speed index value Vc includes the boat speed, the propulsive force command value Fo, or a boat speed target value calculated based on the propulsive force command value Fo.

[0029] The ship speed is obtained from a ship speed measuring device 19 installed on the ship. For example, the ship speed measuring device 19 includes a water speed indicator, a compass, and a wind direction and speed indicator. Alternatively, the ship speed measuring device 19 may include a position acquiring device that acquires the position of the ship. The position acquiring device includes a Global Navigation Satellite System (GNSS) such as GPS. In this case, the ship speed measuring device 19 can calculate the ship speed from changes in the ship's position. The propulsion force command value Fo is obtained from the operation input device 16.

[0030] In the first control mode, when the vessel speed index value Vc is equal to or greater than a predetermined reference value Vr, the processing circuit 15 controls the engine 3 so as to drive the propulsion propeller 2 with the output of the engine 3. While the engine 3 is operating in the first control mode, the processing circuit 15 controls the engine 3 so as to maintain the rotation speed of the engine 3 at a predetermined rotation speed. Furthermore, the processing circuit 15 controls the propulsion propeller 2 so as to change the blade angle based on the thrust command value Fo.

[0031] While the engine 3 is operating in the first control mode, if the propulsive force command value Fo is greater than the propulsive force required to make the rotation speed of the engine 3 a predetermined rotation speed, the processing circuit 15 controls the first power converter 7 to make the motor generator 4 generate electricity with the engine output power corresponding to the difference. The engine output power difference is supplied to the motor generator 4 as power to generate electricity, causing the motor generator 4 to generate electricity, and the electricity generated by the motor generator 4 is supplied to the DC wiring 6. The electricity generated by the motor generator 4 is supplied to electrical equipment on the ship as onboard power. Excess electricity is supplied to the capacitor 9, which is charged.

[0032] In the first control mode, when the vessel speed index value Vc is less than the reference value Vr, the processing circuit 15 stops the engine 3. Furthermore, the processing circuit 15 controls the first power converter 7 to supply power to the motor generator 4 while the engine 3 is stopped, and to drive the propulsion propeller 2 with the rotational output of the motor generator 4. At this time, the power stored in the capacitor 9 is supplied to the motor generator 4 and also to electrical equipment on board the vessel.

[0033] For example, if the operating position of the control lever for setting the propulsive force command value Fo in the operation input device 16 is divided into five stages—STOP, D.SLOW, HALF, FULL, and Nav. FULL—in order of decreasing ship speed target values corresponding to the forward propulsive force command value Fo, the reference value Vr of the ship speed index value Vc set as the propulsive force command value Fo or the ship speed target value may be set to the ship speed index value corresponding to FULL. In this case, the engine 3 is stopped from STOP until just before FULL, and is started from FULL to Navigation FULL. Alternatively, the reference value Vr may be set to the ship speed target value corresponding to HALF, or to a predetermined position between HALF and FULL.

[0034] When the ship speed is low, reducing the engine 3 speed accordingly will cause the engine 3 to operate in a low load range, which may result in a decrease in the thermal efficiency of the engine 3. In particular, when the engine 3 is a gas engine that uses vaporized liquefied gas such as liquefied natural gas as fuel, it is generally difficult to frequently change the engine speed. Furthermore, in gas engines, combustion becomes unstable in the low load range, resulting in the generation of a lot of unburned gas, which can make continuous operation difficult.

[0035] Therefore, in the first control mode, when the ship speed index value Vc is low, such as when the ship is sailing in a bay, the engine 3 is stopped and the motor generator 4 generates the propulsive force for the ship. Furthermore, by maintaining the engine speed at a predetermined speed and using the surplus driving force to power the motor generator 4, the engine 3 is operated only in the range where the thermal efficiency of the engine 3 is high, and the energy efficiency of the entire ship can be improved. This makes it possible to reduce fuel gas consumption and realize a ship with a low environmental impact.

[0036] However, even when the ship speed index value Vc is low, such as when navigating in the bay, there may be cases where high propulsion force is required when making an emergency departure for danger avoidance or in rough sea conditions. In such cases, the processing circuit 15 is switched from the first control mode to the second control mode. In the present embodiment, the operation input device 16 includes a switch 18 for starting the execution of the second control mode.

[0037] Note that the switch 18 may be configured as a physical switch such as a push button switch, or when the operation input device 16 includes a touch panel capable of touch input operations, it may be configured as a virtual switch displayed on the touch panel. The switch 18 may be configured as a switch in which the off state corresponds to the first control mode and the on state corresponds to the second control mode. Alternatively, the switch 18 may include a first switch for executing the first control mode and a second switch for executing the second control mode, and may be configured such that the first switch and the second switch are selectively selected.

[0038] By operating the switch 18, an execution command for the second control mode is transmitted from the operation input device 16 to the controller 14. In the second control mode, the processing circuit 15 controls the engine 3 to maintain the rotational speed of the engine 3 at a predetermined rotational speed regardless of the ship speed index value Vc. The propulsion propeller 2 is driven by the output at the predetermined rotational speed of the engine 3. Further, the processing circuit 15 controls the propulsion propeller 2 to change the blade angle based on the propulsion force command value Fo.

[0039] Note that the engine rotational speed in the second control mode may be the same as or different from the engine rotational speed in the first control mode. That is, the processing circuit 15 controls the engine 3 to maintain the first engine rotational speed when the ship speed index value Vc is equal to or higher than the reference value Vr in the first control mode, and controls the engine 3 to maintain a second engine rotational speed different from the first engine rotational speed in the second control mode.

[0040] Furthermore, the processing circuit 15 controls the first power converter 7 to generate power with the motor generator 4 using the surplus output of the engine 3 obtained by subtracting the propulsion force required to set the rotational speed of the engine 3 to a predetermined rotational speed from the propulsion force command value Fo. The power generated by the motor generator 4 is supplied as shipboard power to electrical equipment within the ship. The surplus power is supplied to the capacitor 9, and the capacitor 9 is charged.

[0041] The operation of the switch 18 can be executed independently of the operation of the operation lever for setting the propulsion force command value Fo at the operation input unit 16. Therefore, for example, the switch 18 can be operated before the start of the ship's voyage to perform the switching to the second control mode in advance. In this case, when the operation lever is positioned at a desired operation position from the stop position, the processing circuit 15 controls the engine 3 and the first power converter 7 in the second control mode from the beginning. Furthermore, after the start of the voyage in the first control mode, it is also possible to switch to the second control mode during the voyage by operating the switch 18.

[0042] According to the above configuration, by executing the first control mode, it is possible to perform low environmental load navigation in which the propulsion propeller 2 is driven by the output of the motor generator 4 in the low speed range, while increasing the propulsion force by using the output of the engine 3 by switching to the second control mode as needed. Therefore, in a ship capable of driving the propulsion propeller 2 by either the engine 3 or the motor generator 4, it is possible to reduce the environmental load while corresponding to the propulsion force required in various situations.

[0043] In addition, since the switching of the control mode can be executed by operating the switch 18, when the user desires the output from the engine 3, the start-up process of the engine 3 can be immediately executed regardless of the control state at that time in the propulsion system 1. Further, since the switch 18 can be operated before the start of the ship's navigation to switch to the second control mode in advance, in the case where poor sea conditions are assumed before the start of navigation, etc., the time required for switching the control mode from navigation by the output from the motor generator 4 to navigation by the output from the engine 3 can be eliminated. Therefore, the time until the required ship speed is reached can be shortened.

[0044] Note that the second control mode ends by an operation to return the switch 18 to the first control mode. In addition to or instead of this, the processing circuit 15 may automatically return from the second control mode to the first control mode when the ship stops, that is, when the ship speed becomes 0. Alternatively, the processing circuit 15 may automatically return from the second control mode to the first control mode when the system is restarted after the system power is turned off by a predetermined system termination operation. Alternatively, the processing circuit 15 may automatically return from the second control mode to the first control mode when the operation position of the operation lever for setting the propulsion force command value Fo in the operation input device 16 is in the stop position. Further, instead of automatic return, a notification device such as a warning lamp or a monitor connected to the controller 14 or the operation input device 16 may notify that the second control mode is being maintained.

[0045] After the second control mode is executed, if a predetermined condition is satisfied, automatic return to the first control mode can suppress the unnecessary continuous execution of the second control mode. Usually, the first control mode is executed as a normal mode with high environmental performance, and the second control mode is executed only when necessary, so that it is possible to prevent the environmental performance of the ship from being wasted.

[0046] Furthermore, in the present embodiment, the second control mode can be executed even without an operation on the switch 18. The processing circuit 15 acquires the navigation environment data of the ship from the navigation environment acquirer 20, and starts the execution of the second control mode when the acquired navigation environment data satisfies a predetermined condition. The navigation environment data includes data such as wind speed or wave height. The wind speed is acquired from an anemometer or the like installed on the ship. The wave height is acquired from wave condition information indicating the distribution of the wave height or the like. The predetermined condition is satisfied, for example, when the wind speed is equal to or higher than the wind speed reference value or when the wave height is equal to or higher than the wave height reference value.

[0047] Alternatively, a two-dimensional condition determination may be performed by combining wind speed levels and wave height levels that are level-divided into multiple levels in a matrix form. For example, when the wind speed level and the wave height level are each level-divided into five levels, the processing circuit 15 may determine that a predetermined condition is satisfied regardless of the other level when the wind speed is at the highest wind speed level 5 or the wave height is at the highest wave height level 5. Further, the processing circuit 15 may determine that a predetermined condition is satisfied if either one of the wind speed level and the wave height level is 4 and the other level is 2 or higher. Further, the processing circuit 15 may determine that a predetermined condition is satisfied if both the wind speed level and the wave height level are 3.

[0048] Thus, when it is determined that the sea state has deteriorated based on the acquired navigation environment data, the second control mode in which the ship is navigated by the engine 3 even in the low speed range is automatically executed. Therefore, appropriate propulsion force can be generated without the user having to judge the deterioration of the sea state. Thereby, the maneuverability of the ship when the sea state deteriorates can be improved.

[0049] Further, the processing circuit 15 acquires the charge rate data of the capacitor 9, and when the value of the acquired charge rate data of the capacitor 9 becomes equal to or less than a predetermined reference value, it starts executing the second control mode. The charge rate data of the capacitor 9 is acquired from the charge rate acquirer 21. For example, the charge rate acquirer 21 includes a voltage detector that detects the voltage of the capacitor 9. The state of charge (SOC) of the capacitor 9 is estimated from the voltage of the capacitor 9 detected by the voltage detector. Thereby, even when the charge rate of the capacitor 9 unexpectedly decreases, the second control mode is automatically executed. In the second control mode, navigation is performed by the engine 3, and power generation is performed by driving the motor generator 4 with the surplus driving force, so that the capacitor 9 can be charged while ensuring the propulsion force of the ship.

[0050] When automatically shifting to the second control mode as described above, a notification device such as a warning lamp or a monitor connected to the controller 14 or the operation input device 16 may notify that the second control mode is being executed. Further, after automatically shifting to the second control mode, when a predetermined condition determined based on the navigation environment data is no longer satisfied, or when the charge rate exceeds the reference value, the processing circuit 15 may control to automatically return to the first control mode. Alternatively, the processing circuit 15 may automatically return from the second control mode to the first control mode when the ship stops, when the system is restarted, or when the operation position of the operation lever for setting the propulsion force command value Fo is located at the stop position.

[0051] As described above, the embodiments of the present disclosure have been described, but the present disclosure is not limited to the above embodiments, and various improvements, changes, and modifications are possible without departing from the spirit thereof.

[0052] [Other Embodiments] For example, in the above-described embodiment, as opportunities for switching from the first control mode to the second control mode, three examples were shown: when there is an operation input to switch 18, when the navigation environment data satisfies a predetermined condition, and when the value of the remaining amount data of the capacitor becomes equal to or less than a predetermined reference value. However, the propulsion system 1 only needs to include at least one of the above three modes, and other modes may not be necessary.

[0053] In addition, in the above-described embodiment, an example was shown in which the motor generator 4 generates electricity in the second control mode, but it is not limited to this. That is, in the second control mode, the processing circuit 15 can also use the output of the motor generator 4 in addition to the output of the engine 3 as the propulsion force of the propulsion propeller 2. For example, in the second control mode, when the difference between the ship speed and the ship speed target value is equal to or greater than a predetermined value, the processing circuit 15 may control to drive the propulsion propeller 2 with an output obtained by adding the output of the motor generator 4 to the output at a predetermined rotation speed of the engine 3. Thereby, the ship speed of the ship can reach the ship speed target value earlier. In addition, the variations in the combination of the operating state of the motor generator 4 and the operating state of the engine 3 can be increased, and appropriate control can be executed for the propulsion force required in various situations.

[0054] In addition to or instead of this, the processing circuit 15 may execute a control mode in which, in the first control mode, the output of the motor generator 4 is used as the propulsion force of the propulsion propeller 2 in addition to the output of the engine 3. For example, in the first control mode, when the ship speed index value Vc is equal to or greater than the reference value Vr and the difference between the ship speed and the ship speed target value is equal to or greater than a predetermined value, the processing circuit 15 may control to drive the propulsion propeller 2 with an output obtained by adding the output of the motor generator 4 to the output at a predetermined rotation speed of the engine 3.

[0055] Furthermore, in the above embodiment, the engine 3 and the motor-generator 4 are connected in parallel to the propulsion propeller 2 via the reduction gear 5, but this is not limiting. For example, the propulsion system 1 may include an intermediate shaft type motor-generator 4 in which the rotor of the generator is fixed to an intermediate shaft connected between the output shaft of the engine 3 and the rotation shaft of the propulsion propeller 2.

[0056] In the above embodiment, the propulsion system 1 is illustrated as being equipped with a controllable pitch propeller as the propulsion propeller 2, but the propulsion system may also be equipped with a propulsion propeller with a fixed blade angle. In this case, the engine speed when driving the propulsion propeller 2 with the output of the engine 2 may be varied in accordance with the ship speed index value Vc.

[0057] The control program in the above embodiment may be configured as a program product that is provided by downloading from an external computer or recorded on a recording medium, or may be configured as a computer product with the control program pre-installed.

[0058] Summary of this disclosure [Item 1] A propulsion system according to one aspect of the present disclosure is a propulsion system for a vessel including an engine mechanically connected to a propulsion propeller, a motor-generator mechanically connected to the engine and capable of generating electricity using the driving force of the engine and transmitting power to the propulsion propeller, a power converter electrically connected to the generator, and a controller that controls the engine and the power converter based on a propulsion force command value, wherein the controller includes a processing circuit, and the processing circuit is configured to be executable by switching between a first control mode and a second control mode, and in the first control mode, acquires a vessel speed index value including a vessel speed, the propulsion force command value, or a vessel speed target value based on the propulsion force command value, and controls the vessel speed index value. When the speed index value is equal to or greater than a predetermined reference value, the engine is controlled to drive the propulsion propeller with the output of the engine, and when the speed index value is less than the reference value, the power converter is controlled to drive the propulsion propeller with the output of the motor-generator while the engine is stopped, and in the second control mode, the engine is controlled to maintain the rotation speed of the engine at a predetermined rotation speed regardless of the ship speed index value, the propulsion propeller is driven with the output of the engine, and the power converter is controlled to generate electricity with the motor-generator using the surplus output of the engine, calculated by subtracting the propulsion force required to make the rotation speed of the engine the predetermined rotation speed, from the propulsion force command value.

[0059] According to the above configuration, by executing the first control mode, the propulsion propeller is driven by the output of the motor-generator at low speeds, enabling navigation with a low environmental impact, while by switching to the second control mode as needed, the propulsive force can be increased using the output of the engine. Therefore, in a vessel that can drive the propulsion propeller by either the engine or the motor-generator, the environmental impact can be reduced while responding to the propulsive force required in various situations.

[0060] [Item 2] The propulsion system of Item 1 includes a switch for starting the execution of the second control mode, and the processing circuit may start the execution of the second control mode based on an operation input to the switch. According to this, since the switching of the control mode can be executed by operating the switch, when the user desires the output by the engine, the starting process of the engine can be immediately executed regardless of the control state at that time in the propulsion system.

[0061] [Item 3] In the propulsion system of Item 1 or 2, the processing circuit may acquire the navigation environment data of the ship and start the execution of the second control mode when the acquired navigation environment data satisfies a predetermined condition. According to this, when it is determined that the weather has deteriorated based on the acquired navigation environment data, the second control mode for navigating by the engine even in a low-speed range is automatically executed. Therefore, appropriate propulsion force can be generated without the user having to judge the deterioration of the weather. Thereby, the maneuverability of the ship when the weather deteriorates can be improved.

[0062] [Item 4] Any of the propulsion systems of Items 1 to 3 includes a capacitor that can be charged by the electric power generated by the motor generator, and the processing circuit acquires the charge rate data of the capacitor and starts the execution of the second control mode when the value of the acquired charge rate data becomes equal to or less than a predetermined reference value. According to this, even when the charge rate of the capacitor unexpectedly decreases, the second control mode is automatically executed. In the second control mode, navigation is performed by the engine, and power generation is performed by driving the motor generator with the surplus driving force, so that the capacitor can be charged while ensuring the propulsion force of the ship.

[0063] [Item 5] In any of the propulsion systems according to Items 1 to 4, in the second control mode, when the difference between the ship speed and the target ship speed is equal to or greater than a predetermined value, the propulsion propeller may be driven by the output obtained by adding the output of the motor generator to the output of the engine at the predetermined rotational speed of the engine. Thereby, the ship speed of the ship can reach the target ship speed quickly.

[0064] [Item 6] In any of the propulsion systems according to Items 1 to 5, the propulsion propeller is a variable pitch propeller whose blade angle can be changed, and the processing circuit controls the engine so as to maintain the rotational speed of the engine at the predetermined rotational speed, and controls the propulsion propeller so as to change the blade angle based on the propulsion force command value.

[0065] [Item 7] A ship control program according to another aspect of the present disclosure includes an engine mechanically connected to a propulsion propeller, a motor generator mechanically connected to the engine, capable of generating electricity using the driving force of the engine, and capable of transmitting power to the propulsion propeller, a power converter electrically connected to the generator, and a controller for controlling the engine and the power converter based on a propulsion force command value. The control program causes the controller to acquire a ship speed index value including the ship speed, the propulsion force command value, or a target ship speed based on the propulsion force command value, control the engine to drive the propulsion propeller by the output of the engine when the ship speed index value is equal to or greater than a predetermined reference value, and control the power converter to drive the propulsion propeller by the output of the motor generator with the engine stopped when the ship speed index value is less than the reference value. The control program is executed by switching between a first control mode and a second control mode. In the second control mode, regardless of the ship speed index value, the rotational speed of the engine is controlled to be maintained at a predetermined rotational speed, the propulsion propeller is driven by the output of the engine, and the power converter is controlled to generate electricity by the motor generator using the surplus output of the engine obtained by subtracting the propulsion force required to change the rotational speed of the engine from the predetermined rotational speed from the propulsion force command value.

[0066] [Item 8] A method for controlling a ship according to another aspect of the present disclosure includes an engine mechanically connected to a propulsion propeller, a motor generator mechanically connected to the engine, capable of generating electricity using the driving force of the engine, and capable of transmitting power to the propulsion propeller, a power converter electrically connected to the generator, and a controller for controlling the engine and the power converter based on a propulsion force command value. The method is a method for controlling a ship, which acquires a ship speed index value including a ship speed, the propulsion force command value, or a ship speed target value based on the propulsion force command value, controls the engine to drive the propulsion propeller by the output of the engine when the ship speed index value is equal to or greater than a predetermined reference value, and controls the power converter to drive the propulsion propeller by the output of the motor generator with the engine stopped when the ship speed index value is less than the reference value. The method switches between and executes a first control mode and a second control mode. In the first control mode, when the ship speed index value is less than the reference value, the power converter is controlled to drive the propulsion propeller by the output of the motor generator with the engine stopped. In the second control mode, regardless of the ship speed index value, the engine speed is controlled to be maintained at a predetermined speed, the propulsion propeller is driven by the output of the engine, and the power converter is controlled to generate electricity by the motor generator using the surplus output of the engine obtained by subtracting the propulsion force required to change the engine speed from the propulsion force command value to the predetermined speed.

Explanation of Signs

[0067] 1 Propulsion system 2 Propulsion propeller 3 Engine 4 Motor generator 7 First power converter (power converter) 9 Battery 14 Controller 15 Processing circuit 18 Switch

Claims

1. An engine mechanically connected to a propulsion propeller, An electric generator mechanically connected to the engine, capable of generating electricity using the driving force of the engine and capable of transmitting power to the propulsion propeller, A power converter electrically connected to the electric generator, A propulsion system for a ship comprising a controller that controls the engine and the power converter based on a propulsion force command value, The controller includes a processing circuit, The processing circuit, Is configured to be able to execute by switching between a first control mode and a second control mode, In the first control mode, a ship speed index value including the ship speed, the propulsion force command value, or a ship speed target value based on the propulsion force command value is acquired, and when the ship speed index value is equal to or greater than a predetermined reference value, the engine is controlled to drive the propulsion propeller by the output of the engine, and when it is less than the reference value, the power converter is controlled to drive the propulsion propeller by the output of the electric generator with the engine stopped, In the second control mode, regardless of the ship speed index value, the engine speed is controlled to be maintained at a predetermined speed, the propulsion propeller is driven by the output of the engine, and the power converter is controlled to generate electricity with the electric generator using the surplus output of the engine obtained by subtracting the propulsion force required to change the engine speed from the propulsion force command value to the predetermined speed. Propulsion system.

2. It is provided with a switch for starting the execution of the second control mode, The processing circuit starts the execution of the second control mode based on an operation input to the switch. The propulsion system according to claim 1.

3. The processing circuit, Acquires navigation environment data of the ship, When the acquired navigation environment data satisfies a predetermined condition, the execution of the second control mode is started. The propulsion system according to claim 1 or 2.

4. It is provided with a storage battery that can be charged by the power generated by the electric generator, The processing circuit, Acquires the charge rate data of the storage battery, When the value of the acquired charge rate data becomes equal to or less than a predetermined reference value, the execution of the second control mode is started. The propulsion system according to claim 1 or 2.

5. In the second control mode, when the difference between the ship speed and the target ship speed is equal to or greater than a predetermined value, the propulsion propeller is driven by an output obtained by adding the output of the motor generator to the output of the engine at the predetermined rotational speed of the engine, according to the propulsion system of claim 1 or 2.

6. The propulsion propeller is a variable pitch propeller capable of changing the blade angle, The processing circuit, controls the engine so as to maintain the rotational speed of the engine at the predetermined rotational speed, and controls the propulsion propeller so as to change the blade angle based on the propulsion force command value, according to the propulsion system of claim 1 or 2.

7. An engine mechanically connected to a propulsion propeller, a motor generator mechanically connected to the engine, capable of generating electricity using the driving force of the engine, and capable of transmitting power to the propulsion propeller, a power converter electrically connected to the motor generator, and a controller for controlling the engine and the power converter based on a propulsion force command value. A control program for a ship, comprising: The control program causes the controller to acquire a ship speed index value including the ship speed, the propulsion force command value, or a target ship speed based on the propulsion force command value, control the engine to drive the propulsion propeller by the output of the engine when the ship speed index value is equal to or greater than a predetermined reference value, and control the power converter to drive the propulsion propeller by the output of the motor generator with the engine stopped when the ship speed index value is less than the reference value; a first control mode; regardless of the ship speed index value, control to maintain the rotational speed of the engine at a predetermined rotational speed, drive the propulsion propeller by the output of the engine, and control the power converter to generate electricity with the motor generator using the surplus output of the engine obtained by subtracting the propulsion force required to set the rotational speed of the engine to the predetermined rotational speed from the propulsion force command value; a second control mode; and execute by switching between the two control modes. A control program.

8. An engine mechanically connected to a propulsion propeller, a motor generator mechanically connected to the engine, capable of generating electricity using the driving force of the engine, and capable of transmitting power to the propulsion propeller, a power converter electrically connected to the motor generator, and a controller for controlling the engine and the power converter based on a propulsion force command value. A control method for a ship, comprising: Obtain a ship speed index value including the ship speed, the propulsion force command value, or a ship speed target value based on the propulsion force command value, and control the engine to drive the propulsion propeller by the output of the engine when the ship speed index value is equal to or greater than a predetermined reference value, and control the power converter to drive the propulsion propeller by the output of the motor generator with the engine stopped when the ship speed index value is less than the reference value; and a first control mode, Regardless of the ship speed index value, control to maintain the engine speed at a predetermined speed, drive the propulsion propeller by the output of the engine, and generate power with the motor generator using the surplus output of the engine obtained by subtracting the propulsion force required to set the engine speed to the predetermined speed from the propulsion force command value. A control method that switches between and executes a second control mode for controlling the power converter.

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