JP5496561B2 - Marine propulsion device - Google Patents

Description

  The present invention includes a first propeller that is attached to a hull and driven by a main engine, and is pivotally attached to the outside of the hull to form a counter-rotating system with the first propeller, and is driven by an electric motor. The present invention relates to a marine propulsion device (tandem type and hybrid type counter-rotating system) including a second propeller, and more particularly to control of an electric motor that drives a second propeller.

  Recently, in order to improve the propulsion efficiency of a ship, a counter-rotating system is used for an electric propulsion ship or the like. As shown in FIG. 8A, the single propeller generates both rotational flow and axial flow behind the propeller 100, but only the axial flow contributes to propulsion. The energy of the rotating flow shown does not contribute to the propulsion.

  However, as shown in FIG. 8B, in the counter rotating propeller, the rotation directions of the front propeller 201 and the rear propeller 202 are opposite to each other, and the energy of the rotational flow of the front propeller 201 is recovered by the rear propeller 202. It is possible to improve propulsion efficiency by rectifying the directional flow, eliminating energy loss due to the rotating flow, and leaving only the axial flow B behind.

  FIG. 9 shows an example of a marine propulsion device designed to improve the propulsion efficiency by such a contra-rotating propeller. This marine propulsion device 50 is known as a hybrid type counter-rotating system. A front propeller 4 driven by a main engine 9 is provided on the stern 3 of the hull 2, and the front propeller 4 is disposed outside the hull 2. A pod propulsion device 5 having a rear propeller 6 driven by an electric motor 15 is arranged in tandem at the rear.

  As shown in FIG. 9, the front propeller 4 is connected to a main engine 9 (engine) inside the hull 2 via a speed reducer 8 and a drive shaft 7. The pod propulsion device 5 includes a strut 11 that is pivotally mounted on a platform 10 provided at the bottom of the stern 3 of the hull 2 about a vertical axis, a pod 12 that is attached to the strut 11, and a pod 12 The rear propeller 6 and the front propeller 4 constitute a counter-rotating propeller. The rear propeller 6 and the front propeller 4 are attached to the front end of the front propeller 4 and opposed to the front propeller 4. An electric motor 15 for the pod propulsion device 5 is arranged inside the stern 3 of the hull 2, and further inside the strut 11 and the pod 12 via the drive shaft 16 and the gear box 17 on the platform 10. The rear propeller 6 can be driven through a transmission mechanism (not shown). The pod propulsion device 5 can be turned around a vertical axis by a hydraulic motor (not shown).

  As shown in FIG. 9, the marine propulsion device 50 includes a plurality of generators 21 and a plurality of auxiliary engines 20 that respectively drive the plurality of generators 21 on the ship. The electric power generated by the generator 21 is sent to the inverter 51 through the distribution board 22, and the electric motor 15 is driven by the control of the inverter 51 and is also supplied to the inboard equipment through the distribution board 22. How many of the auxiliary engines 20 among the plurality of auxiliary engines 20 are driven is determined by the total electric energy that is the sum of the electric power consumed by the electric motor 15 and the inboard power consumed by the inboard equipment, When the total electric power becomes larger than the permissible limit per generator 21 driven by one auxiliary engine 20, the second and subsequent auxiliary engines 20 are sequentially started to obtain the required total electric energy. Proper power generation is performed.

  In this marine propulsion device 50, the electric motor 15 that drives the rear propeller 6 is controlled by the inverter 51 as described above. In this control, the rotation of the electric motor 15 is taken into consideration with the load balance with the front propeller 4. A rotational speed control method is used in which the number is set and the speed of the rear propeller 6 is controlled.

  As a method for controlling the electric motor, torque control is also known in addition to the rotational speed control used in the marine propulsion device 50. For example, Patent Document 1 below discloses torque control of an electric motor for the purpose of performing an operation adapted to acceleration / deceleration characteristics required by a load, such as alleviating an impact on a machine during a sudden stop. Patent Document 2 listed below discloses a torque control technique for an electric motor in an electric propulsion ship for the purpose of avoiding excessive increase in power consumption during turning, cavitation, etc., or damage to the motor or battery. Is disclosed.

JP-A-52-22713 JP-A-8-258793

  According to the conventional marine propulsion device 50 shown in FIG. 9 which is a hybrid type counter-rotating system, the propulsion efficiency is improved by the counter-rotating effect, and two types of propulsion means including the main engine 9 and the electric motor 15 are provided. Therefore, even if one system breaks down, there is an advantage that normal navigation is possible with the other system. However, the rotational speed of the electric motor 15 is controlled by the inverter 51. was there.

  In a stormy weather, if a racing phenomenon occurs in which the propeller repeatedly enters and leaves underwater due to the influence of waves, the rotation of the rear propeller 6 varies due to sudden load fluctuations. For example, when the rear propeller 6 comes out of the water, the load decreases, so the rotation increases. When the rear propeller 6 enters the water, the load increases, and the rotation decreases. When the load fluctuation is severe, the power generating auxiliary engine 20 responds to the load fluctuation, causing a phenomenon (hunting) in which the fuel rack for controlling the fuel injection amount suddenly moves in the fuel injection device. In addition, the fuel rack may be finely operated within a small moving range (jiggle), resulting in premature wear of the fuel rack and its related parts.

  Further, in the marine propulsion device of the hybrid counter rotating system, it is necessary to balance the load between the front propeller 4 and the rear propeller 6 in order to improve the propulsion efficiency. For example, when the ship speed is set to a certain value, in order to balance the load between the front propeller 4 and the rear propeller 6, an operation for adjusting the output ratios of the propellers 4 and 6 to be the same is performed. However, in order to do so, it is necessary to adjust the two speed levers for controlling the propellers 4 and 6, respectively. If the output ratio of one propeller is changed, the output ratio of the other propeller will be affected and change. Therefore, the adjustment work is not easy. If the output ratio of the front propeller 4 is larger than the output ratio of the rear propeller 6, the electric motor 15 may be in a regenerative state as will be described later. Conversely, the output ratio of the rear propeller 6 is the output ratio of the front propeller 4. If it is larger than, cavitation may occur in the rear propeller 6.

  Further, for example, when the outputs of the front propeller 4 and the rear propeller 6 are lowered during deceleration, the rear propeller 6 driven by the electric motor 15 is controlled by the inverter 51 so that the number of revolutions is reduced. It does not drop immediately, and tries to sail with inertia. For this reason, the electric motor 15 is rotated by the rear propeller 6 that has received the water flow. When the electric motor 15 rotates above the commanded rotational speed, the electric motor 15 falls into a regenerative behavior that acts as a generator, and the electric motor 15 generates power. As a result, the current flows backward toward the machine 21. As described above, regeneration may also occur when the output ratio of the front propeller 4 is too large compared to the output ratio of the rear propeller 6. In such a case, there is no problem as long as the ship is fully equipped with a power storage system, but in other cases, it is necessary to radiate energy with a resistor in a regenerative state. However, there is an allowable amount in the resistor, and it is inevitable that trouble will occur if the resistor is exceeded, and the operator should be careful in maneuvering the ship or adjusting the load balance to avoid such inconvenience. It was necessary to devote a lot to the work, which was very complicated.

  Next, according to the conventional marine propulsion device 50 shown in FIG. 9 which is a hybrid type counter-rotating system, the plurality of auxiliary engines 20 and the generator 21 satisfy the electric demand. As described above, the electric motor If the total power amount, which is the sum of the power consumed by the power 15 and the power in the ship, increases, the number of the auxiliary engines 20 and the generators 21 to be driven is sequentially increased as necessary. There are no particular restrictions on the number of auxiliary engines 20 and generators 21. However, according to the knowledge of the inventors of the present invention, it is considered that the following problems are caused by the driving method of the auxiliary engine and the generator in the conventional hybrid type counter rotating system.

  FIG. 10 shows a conventional marine propulsion device 50 that is a hybrid type counter-rotating system. The total amount of electric power consumed by the electric motor 15 and the electric power in the ship, the auxiliary engine 20 operating at that time, and The load in operation is schematically displayed. Although there are four auxiliary engines 20 and four generators 21 in FIG. 9, two auxiliary engines 20 and generators 21 are illustrated as shown in FIG. In FIG. 10, the left figure on the left side of the white arrow shows the case where the total amount of electricity can be covered by the amount of electricity generated by one generator, and the right figure on the right side shows the amount of electricity generated by one generator. It shows the case of exceeding.

  Conventionally, when the total amount of electric power increases, the number of driven auxiliary engines 20 and generators 21 is sequentially increased as necessary. For this reason, when shifting from the state of the left figure of FIG. 10 to the state of the right figure, that is, from the state where the total electric energy is within the permissible limit per generator 21, the total electric energy is When the permissible limit per vehicle is exceeded, the second auxiliary engine 20 (power generation auxiliary machine 2) is started in addition to the first auxiliary engine 20 (power generation auxiliary machine 1). This state is an inefficient state in which the two power generation auxiliary machines 20 each bear a total power amount slightly exceeding the permissible limit per generator 21 with a load of half or less. When two auxiliary engines 20 are operated at such a low load in this way, not only the fuel consumption deteriorates, but also carbon adheres to the combustion chamber of the auxiliary engine 20 or the exhaust valve blows out. It will cause wear and damage.

  Further, when the total power amount that is the sum of the power consumed by the electric motor 15 and the inboard power fluctuates, for example, in the vicinity of the allowable power generation amount of one generator 21, the second generator 21 and the auxiliary engine 20 Repeated activation and stop. Even in such an operating state, the fuel consumption is deteriorated, and the generator 21 and the auxiliary engine 20 themselves are worn and damaged.

  Further, in the conventional marine propulsion device 50 that is a hybrid type counter-rotating system, the front propeller 4 is driven by the main engine 9, and the pod propulsion device 5 having the rear propeller 6 may be used as a rudder. is there. In such a case, a constant low torque is applied to the electric motor 15 that drives the rear propeller 6. If no torque is applied to the electric motor 15 of the rear propeller 6 in such a boat maneuvering method, the rear propeller 6 will rotate in accordance with the direction in which the ship travels, but the load received from the water flow is not necessarily constant. This is because a phenomenon called chattering in which the gear of the drive mechanism of the rear propeller 6 rattles occurs. Therefore, it is necessary to apply a constant torque to the rear propeller 6 that is idled by the front propeller 4 by the electric motor 15 and to control it to rotate in accordance with the traveling direction.

  However, when the pod propulsion device 5 is used as a rudder in this way, the electric motor 15 of the rear propeller 6 has no power consumption other than applying a certain low torque to prevent chattering as described above. There is a problem that the load of the auxiliary engine 20 that drives one generator 21 that supplies electric power is low and fuel consumption is poor.

  The present invention aims to solve the above-described conventional problems, and in a hybrid type counter-rotating system, the fuel consumption is good, the parts of the auxiliary engine are hardly consumed, and the load adjustment of the front propeller and the rear propeller is adjusted. The object is to provide a marine propulsion device that is easy.

The marine propulsion device described in claim 1 is:
A first propeller provided at the stern of the hull;
A main engine provided on the hull for driving the first propeller;
The first propeller and the counter-rotating propeller are configured outside the stern of the hull so as to face the first propeller, and the swivel is pivotable about a swivel axis parallel to the vertical direction. A second propeller attached to the hull;
An electric motor provided on the hull to drive the second propeller;
A plurality of generators provided on the hull for supplying electric power to the electric motor, and a plurality of auxiliary engines for driving the plurality of generators, respectively,
Yes, and the torque control for driving the electric motor by the command torque to a propulsion device for a row cormorants舶 by inverters,
In the torque control, by giving a constant torque limit to the drive command signal given to the inverter, the total electric power that is the sum of the electric power of the electric motor and the electric power in the ship is controlled so as not to exceed a predetermined allowable limit. It is characterized by that.

The marine propulsion device according to claim 2 is the marine propulsion device according to claim 1 ,
The torque limit given to the drive command signal is defined by a ratio of electric power of the electric motor or a ratio of electric power in the ship in the total electric power, and the ratio is set in a plurality of stages. The torque limit can be arbitrarily set by selecting the ratio according to demand.

The marine propulsion device according to claim 3 is the marine propulsion device according to claim 1 or 2 ,
The inverter has a function of performing rotation speed control for driving the electric motor at a commanded rotation speed, and sets the control mode of the electric motor by the inverter to either the torque control or the rotation speed control. It is configured so that it can be used.

According to the marine propulsion device described in claim 1, a counter rotating system is constituted by a front propeller driven by a main engine and a rear propeller driven by an electric motor, and electric power is supplied to the electric motor and inboard equipment. In a marine propulsion device that performs a plurality of generators and auxiliary engines, since the electric motor is driven by torque control of an inverter, regeneration does not occur even if the rotational speed of the electric motor increases due to navigation conditions, and A navigation situation in which the rotational speed of the electric motor decreases and the electric motor reverses to cause regeneration can hardly occur. Therefore, even if the ship is not equipped with a power storage system, the operator does not have to worry about the occurrence of regeneration, and there is a wide range in which the load balance between the front propeller and the rear propeller can be set to increase propulsion efficiency. Therefore, adjustment work becomes easy. In other words, if the torque of the electric motor that drives the rear propeller is set to be constant, it is possible to perform appropriate ship maneuvering by adjusting the output of the front propeller once, and it is necessary to frequently adjust the load balance. Nor. In addition, according to torque control, the load of the rear propeller does not fluctuate greatly even if there is a sudden load fluctuation due to the racing phenomenon in stormy weather, and the fuel rack of the fuel injection device is unlikely to cause hunting or jiggle. There is no premature wear of parts.
According to the marine propulsion device described in claim 1, in addition to the above effects, in the torque control, by giving a constant torque limit to the drive command signal given to the inverter, the electric power of the electric motor It is possible to control so that the total amount of power that is the sum of the power in the ship does not exceed a predetermined allowable limit. Therefore, for example, if the permissible limit per generator is a predetermined permissible limit, the total amount of power is limited within the range of power that can be generated by one generator, and only one auxiliary engine has fuel efficiency. It is possible to improve the fuel consumption by driving in an optimal load state with low wear and avoid the wear of the auxiliary engine due to the drive in the low load region. When using a pod propulsion device with a rear propeller exclusively as a rudder, when applying a constant low torque to the rear propeller to prevent chattering from occurring in the drive system of the rear propeller In order to improve the overall fuel efficiency, it is possible to drive a single generator that achieves this power consumption with optimal fuel consumption, low wear and optimal load conditions, and to suppress the output of the front propeller driven by the main engine. Is obtained.

According to the marine propulsion device described in claim 2 , in addition to the effect of the marine propulsion device according to claim 1 , the torque limit given to the drive command signal is set, for example, as a ratio of the electric power in the ship in the total electric energy. It can be set in multiple stages according to For example, the power demand on the ship can be set relatively low, such as 30% of the power that can be generated by one generator (allowable limit), or relatively high as 60%, This can be selected according to the actual power demand in the ship. If the onboard power demand is about 30%, setting the torque limit at this stage will consume approximately 30% of the onboard power out of the power that can be generated by one generator (allowable limit). The remaining 70% is consumed by electric power of the electric motor, and one auxiliary engine can be driven in a state of good fuel consumption in the optimum load state. Also, if the power demand on the ship reaches about 60%, if the torque limit is set at this stage, 60% of the power that can be generated by one generator (allowable limit) will be consumed by the ship power. The remaining 30% is consumed by electric power of the electric motor, and similarly to the case of 30%, one auxiliary engine can be driven in an optimum load state with good fuel consumption. To the extent that the power consumption of the ship increases and the output of the electric motor decreases, it is only necessary to increase the thrust of the forward propeller by increasing the load on the main engine. Even in this case, the effect of improving the fuel consumption can be obtained as a whole.

According to the marine propulsion device described in claim 3 , in addition to the effect of the marine propulsion device according to claim 1 or 2 , the control mode of the electric motor by the inverter is set to either torque control or rotation speed control. There is an effect that can be set by switching. Thus, in the case of a ship maneuvering situation such as when entering and leaving a port where responsiveness is particularly required, the control mode of the electric motor can be switched from torque control to rotation speed control to achieve the object. In other words, in torque control, the inverter controls the torque by giving a torque command signal suitable for the target value torque to the electric motor, and the actual rotational speed detected by the sensor is applied to the inverter as in the rotational speed control. Unlike the control method with good followability that achieves the target speed by feedback, the mode is slightly less responsive.Therefore, when maneuvering when entering or leaving a port that requires responsiveness, It is possible to cope with the changeover switch by switching the control mode of the electric motor by the inverter to the rotational speed control.

1 is a schematic structural diagram of a marine propulsion device according to a first embodiment of the present invention. It is a circuit diagram of the limiter provided in the alarm panel in the marine propulsion device of the first embodiment. In order to explain the operation when the limiter function and limit value provided on the alarm panel are selected in the marine propulsion device of the first embodiment, a handle notch (0 to 10) indicating the operation amount of the speed control lever, It is a graph which shows the condition where a boundary value is added to a torque command signal with a limiter while showing the relationship of the torque command signal which an inverter outputs corresponding to this. When the inboard power demand of the marine propulsion device, which is a hybrid counter-rotating system, is about 30% of the allowable limit of one generator, the total power amount that is the sum of the power consumed by the electric motor and the inboard power FIG. 2 is a diagram schematically showing an auxiliary engine operating at that time and a load during the operation, and a left diagram showing a conventional example in which torque limit control is not performed, and the marine vessel of the first embodiment performing torque limit control It is a figure shown by contrasting the right figure showing a propulsion device. When the inboard power demand of the marine propulsion device that is a hybrid type counter-rotating system is about 60% of the allowable limit of one generator, the total power amount that is the sum of the power consumed by the electric motor and the inboard power FIG. 2 is a diagram schematically showing an auxiliary engine operating at that time and a load during the operation, and a left diagram showing a conventional example in which torque limit control is not performed, and the marine vessel of the first embodiment performing torque limit control It is a figure shown by contrasting the right figure showing a propulsion device. In the marine propulsion device of the first embodiment, a diagram schematically showing the total electric power that is the sum of the electric power consumed by the electric motor and the in-board electric power, the auxiliary engine that is operating at that time, and the load that is being operated. The figure on the right shows the case where the onboard power demand is about 30% or about 60% of the allowable limit of one generator and the limit-free case (when no limit is applied). is there. In the marine propulsion device that is a hybrid type counter-rotating system, when the front propeller is the main propeller and the rear propeller is used as a rudder, the total electric energy that is the sum of the electric power consumed by the electric motor and the inboard power, and FIG. 2 is a diagram schematically showing the auxiliary engine operating at that time and the load during the operation, and a left diagram showing a conventional example in which torque limit control is not performed, and the marine propulsion of the first embodiment performing torque limit control It is a figure shown contrasting the right figure which shows an apparatus. (A) is a perspective view illustrating the energy of propulsion by a rotating flow of a single propeller, and (b) is a perspective view illustrating the energy of propulsion by a counter rotating propeller. FIG. 2 is a schematic structural diagram of a conventional marine propulsion device that is a hybrid counter-rotating system. In a conventional marine propulsion system that is a hybrid type counter-rotating system, the total electric power that is the sum of the electric power consumed by the electric motor and the in-board electric power, the auxiliary engine that is operating at that time, and the load during the operation are schematically shown The left figure which shows the case where it is operating within the permissible limit per generator, and the right figure which shows the case where it exceeds the permissible limit per generator It is a figure which compares and shows.

  A marine propulsion device 1 according to the present embodiment shown in FIG. 1 has a first propeller 4 disposed on the stern 3 of a hull 2 and a pod propulsion having a second propeller 6 behind the first propeller 4. This is an azimuth thruster of a hybrid type counter-rotating system in which the apparatus 5 is arranged in tandem and the counter-rotating propeller is constituted by the first and second propellers 4 and 6.

  As shown in FIG. 1, a first propeller 4, which is a forward propeller, is attached to a drive shaft 7 inside the hull 2, and this drive shaft 7 is connected to a main engine 9 (diesel via a reducer 8. Engine).

  As shown in FIG. 1, the pod propulsion device 5 is attached to a platform 10 provided at the bottom of the stern 3 of the hull 2 so as to be rotatable around a vertical axis. First, the pod propulsion device 5 has a substantially plate-like strut 11 disposed behind the first propeller 4 in a space below the stern 3. The strut 11 is attached to the platform 10 so as to be pivotable about a vertical axis, and can be set in an arbitrary direction by being pivoted by a hydraulic motor (not shown). Further, the pod propulsion device 5 is disposed facing the pod 12 which is a housing attached to the substantially central portion of the strut 11 and the front first propeller 4 attached to the front end portion of the pod 12. A rear second propeller 6 is provided. An electric motor 15 for driving the pod propulsion device 5 is disposed inside the stern 3 of the hull 2. The electric motor 15 is connected to the second propeller 6 via a drive shaft 16 and a gear box 17 on the platform 10 and further via a transmission mechanism (not shown) inside the strut 11 and the pod 12. Thus, the second propeller 6 can be driven in the opposite direction to the first propeller 4.

  As shown in FIG. 1, the electric motor 15 that drives the pod propulsion device 5 is supplied with electric power from a generator 21 that is driven by the auxiliary engine 20. The auxiliary engine 20 in this example is a diesel engine as in the main engine. In this example, the auxiliary engine 20 and the generator 21 are installed as a set, and in particular, the output of each set of the auxiliary engine 20 and the power generation capacity of the generator 21 are the same. However, the output of the auxiliary engine 20 and the power generation capacity of the generator 21 are not necessarily the same between the groups, and the number of sets of the auxiliary engine 20 and the generator 21 to be installed is not limited to four. It is sufficient that there are a plurality of sets, that is, two or more sets. The main points such as the output order of the auxiliary engine 20 and the generator 21, the number of installed sets, and the driving order when increasing the number of sets to be driven according to the power demand are the power consumption of the electric motor 15 and It can be arbitrarily determined according to the power demand in the ship. In particular, if the driving order in the case of increasing the number of driven auxiliary engines 20 and generators 21 in accordance with the power demand is appropriately changed, the auxiliary engines 20 and the generators 21 of all the sets are evenly distributed. It is avoided that an excessive load is applied to the specific set of auxiliary engine 20 and the generator 21 to cause wear.

  As shown in FIG. 1, the electric power from each generator 21 is supplied to each facility in a ship as a ship power supply via a switchboard. The switchboard 22 has a function of automatically starting and stopping each auxiliary engine 20 according to the total amount of electric power that is the sum of the electric power consumed in the ship and the electric motor 15, and the auxiliary engine 20 and the generator The number of operating units is adjusted.

  The inverter 23 shown in FIG. 1 is a control means for the electric motor 15 and controls the electric motor 15 by selecting either the rotational speed control or torque control mode, and from the generator 21 driven by the auxiliary engine 20. Electric power can be supplied to the electric motor 15 in the selected control mode. The control by the inverter 23 is performed by an alarm panel 24 installed in the engine room of the ship and a speed control lever 25 installed in the steering room of the bridge. The lever 25 can be provided not only in the wheelhouse but also in the wing.

  As shown in FIG. 1, the drive command signal output from the lever 25 is input to the limiter 26 of the alarm panel 24. In this example, after torque control is adopted for control of the electric motor 15 by the inverter 23, torque limit control is performed in which the limiter 26 provides a torque limit to the drive command signal from the lever 25.

  The torque limit control by the limiter 26 refers to the electric power of the electric motor 15 by applying a constant torque limit (limit value) to the drive command signal given from the lever 25 to the inverter 23 in the torque control of the electric motor 15 by the inverter 23. It means that control is performed so that the total power amount, which is the sum of the power in the ship, does not exceed a predetermined allowable limit. Here, as the predetermined allowable limit, an allowable limit of the amount of electric power that can be generated by one generator 21 is set. That is, when the electric motor 15 is torque controlled during steering, even if the amount of operation of the lever 25 is increased, the drive command signal output from the lever 25 is a current value after a certain value exceeding the limit. The torque command signal given to the electric motor 15 by the inverter 23 receiving this drive command signal is also limited, so that the total power amount does not exceed the amount of power generated by one generator 21. Thus, torque control is performed.

FIG. 2 shows the configuration of the limiter 26 arranged between the lever 25 and the inverter 23. The configuration other than the limiter 26 of the alarm panel 24 shown in FIG. 1 is omitted in FIG. The limiter 26 applies different torque limits to the drive command signal sent from the lever 25, limiters 1 and 2 set to different limit values, switches 28a and 28b for selecting them, and a torque limit for the drive command signal. The control means is connected in parallel so that the switch 28c of the stage of 100% torque that is sent to the inverter 23 as it is without being given is alternatively turned on. The set value of each limiter can be freely set by the regulators 27a and 27b such as variable resistors.
The limiter 26 shows an example of a hardware configuration for setting a desired torque limit to perform torque limit control, but an equivalent function can be realized by a microcontroller and software.

  Each torque limit in the first stage and the second stage of the limiter 26 is defined in accordance with the ratio of the power in the ship to the total power amount. The consumption of inboard power other than the power used by the electric motor 15 used for propulsion is calculated by dividing it when the demand is relatively low and when it is relatively high, or is obtained by experiment. Based on the result, when the power consumption of the ship is small, about 30% of the power that can be generated by one generator 21 can be used as the ship power. Is set to one stage so that the electric motor 15 can be used.

  FIG. 3 is a diagram showing a relationship between an operation amount (horizontal axis, handle notch) based on the number of notches of the handle and a torque command signal (vertical axis) sent from the inverter 23 to the electric motor 15. In the case of the first stage shown in FIG. 2, the torque command signal increases by the operation of the lever 25, but is saturated in a line corresponding to about 70% or less of the electric energy by one generator 21. Accordingly, at this time, about 30% of the amount of power that can be generated by one generator 21 can be used as inboard power. At this time, only one auxiliary engine 20 is driven.

  Similarly, when the amount of inboard power consumption is large, approximately 60% of the amount of power that can be generated by one generator 21 can be used as inboard power. A two-stage torque limit was set so that the motor 15 could be used.

  In the case of the two stages shown in FIG. 3B, the torque command signal is increased by the operation of the lever 25, but the amount of electric power by one generator 21 is reduced earlier than in the case of FIG. Saturates at a line corresponding to 40% or less. Accordingly, at this time, about 60% of the amount of electric power that can be generated by one generator 21 can be used as the inboard power. At this time, only one auxiliary engine 20 is driven.

  The 100% stage is a case where no torque limit is applied, and the drive command signal from the lever 25 passes directly through the limiter 26 and is directly applied to the inverter 23, so that the torque command signal that the inverter 23 gives to the electric motor 15. Increases in accordance with the operation of the lever 25 without any particular limitation.

  As shown in FIG. 3C, in the case of 100%, the torque command signal increases in proportion to the operation amount of the lever 25. As a result, if the total amount of electric power, which is the sum of the electric power of the electric motor 15 and other inboard power, increases, the number of sets of the auxiliary engine 20 and the generator 21 to be driven increases as needed by the control by the switchboard 22. It will be done.

The torque limit control of the limiter 26 performed in the torque control will be described in more detail with reference to FIGS.
FIG. 4 is a diagram showing the total amount of power and the load state of each auxiliary engine 20 (power generation auxiliary machines 1 and 2) when the onboard power demand is relatively small at about 30% in the torque control of the electric motor 15. The left figure on the left side of the white arrow shows the case where the limit is not limited, and the right figure shows the case where one stage of the limiter 26 is selected in this example.

  In the case where the limit shown in the left diagram is not applied, if the total power exceeds the power generation capacity (allowable limit) of one generator 21, the auxiliary engine 20 is driven by 2 to drive the second generator 21. The platform starts. That is, the power demand is slightly higher than the amount of power generated by one generator 21, but in order to cover this, the two auxiliary engines 20 (power generation auxiliary machines 1 and 2) are each loaded at a low load factor of less than half. It is driven, fuel consumption is bad, and each auxiliary engine 20 is also worn out.

  As shown in the right diagram of FIG. 4, when one stage of the limiter 26 is selected in this example under substantially the same conditions as the left diagram, the total power is the power generation capacity (allowable limit) of one generator 21. Therefore, the second auxiliary engine 20 does not start, and the power demand that does not exceed the amount of power generated by one generator 21 is reduced to one auxiliary engine 20 (power generation). The auxiliary machine 1) is driven by a high load factor of about 80%, which is good for fuel efficiency and wear of each auxiliary engine 20 is small.

  FIG. 5 is a diagram showing the total electric energy and the load state of each auxiliary engine 20 (power generation auxiliary machines 1 and 2) when the onboard power demand is relatively high at about 60% in the torque control of the electric motor 15. The left figure shows the case where the limit is not limited, and the right figure shows the case where two stages of the limiter 26 are selected in this example.

  In the case of not limiting the limit shown in the left figure, the total power greatly exceeds the power generation capacity (allowable limit) of one generator 21, and two auxiliary engines are used to drive the second generator 21. 20 is driven. In other words, while the power demand is about 1.5 times the amount of power generated by one generator 21, two auxiliary engines 20 (power generation auxiliary machines 1 and 2) are each loaded with a low load of about half. Therefore, the fuel efficiency is poor, and each auxiliary engine 20 is also worn out.

  As shown in the right diagram of FIG. 5, when two stages of the limiter 26 are selected in this example under substantially the same conditions as the left diagram, the total power is the power generation capacity (allowable limit) of one generator 21. Therefore, the second auxiliary engine 20 does not start, and the power demand that does not exceed the amount of power generated by one generator 21 is reduced to one auxiliary engine 20 (power generation). The auxiliary machine 1) is driven by a high load factor of about 80%, which is good for fuel efficiency and wear of each auxiliary engine 20 is small.

  Thus, according to the torque limit control method in the torque control of this example, the consumption state of the inboard power is confirmed with a meter such as the switchboard 22 and the limit stage corresponding to this is selected with the limiter 26, and the inverter 23, the torque control of the electric motor 15 is performed, so that the auxiliary engine 20 is always operated in an optimum load state with good fuel consumption and low wear, and maintenance of the auxiliary engine 20 and improvement of the fuel consumption can be achieved. The optimum load state with good fuel consumption and low wear varies depending on the structure and scale of the engine, but it is generally considered that the load factor is in the range of 60% to 90%.

  On the other hand, by adding a torque limit to the electric motor 15 that drives the rear second propeller 6, there is a concern about a decrease in ship speed, but according to the tandem type and hybrid type counter-rotating system of this example, Since the range of adjustment of the load balance between the front and rear propellers 4 and 6 that provides high propulsion efficiency is wide, the output of the main engine 9 that drives the front first propeller 4 can be increased as necessary during normal navigation. Even when the torque of the second propeller 6 at the rear is lowered, the desired ship speed can be obtained with the high propulsion efficiency by increasing the output of the main engine 9. Thus, according to the marine propulsion device of this example, even if the output of the main engine 9 is increased, it is better to operate the auxiliary engine 20 in the optimum load state by limiting the torque by the electric motor 15 as a whole. The fuel economy of will improve.

  However, when the ship speed is insufficient due to the navigation situation or the like and a high output of the electric motor 15 is required, the ship maneuvering is given priority over the fuel efficiency, and the 100% torque stage (switch 28c) of the limiter 26 may be selected. it can. FIG. 6 is a diagram showing the total electric energy and the load state of each auxiliary engine 20 (power generation auxiliary machines 1 and 2) in the torque control of the electric motor 15, and the left figure is under control by the first or second limit stage. The figure which shows a state and the right figure are figures which show the state under control by the 100% stage (namely, when a limit is not restrict | limited) of the limiter 26. FIG.

  In the case of one stage or two stages of the limiter 26 shown in the left diagram of FIG. 6, the total power is limited and is below the power generation capacity (allowable limit) of one generator 21. In order to drive, only one auxiliary engine 20 (power generation auxiliary machine 1) is driven in an optimal load state. Therefore, the fuel consumption is good and the wear of the auxiliary engine 20 is small. In addition, when there is a concern about a decrease in ship speed in this state, as described above, it is possible to obtain a sufficient ship speed while maintaining good fuel consumption by increasing the output of the main engine 9.

  In the case of the limiter 26 shown in the right diagram of FIG. 6 in the 100% stage (limit free), the power consumption of the electric motor 15 is not limited, so the total power exceeds the power generation capacity (allowable limit) of one generator 21. In order to drive the two generators 21, the two auxiliary engines 20 (power generation auxiliary machines 1 and 2) are driven in a low load state with a load factor of about 50%. If such a control state is taken, the fuel consumption is deteriorated as compared with the case where the limiter 26 is controlled in one or two stages, but the output by the electric motor 15 can also be increased. It is possible to obtain

Further, in the marine propulsion device of this example, the propulsive force is obtained by the front first propeller 4 driven by the main engine 9, and the pod propulsion device 5 that drives the rear second propeller 6 by the electric motor 15. May take a ship maneuvering method that is used exclusively as a rudder. As described above, in such a case, a certain low torque is applied to the electric motor 15 that drives the rear second propeller 6, and the rear second propeller 6 is driven by a load received from the water flow or the like. It prevents chattering from occurring in the drive mechanism. However, as described above, in such a driving method, the electric motor 15 of the rear second propeller 6 has no power consumption other than a constant low torque for preventing chattering. There is a problem that the load of the auxiliary engine 20 that drives one generator 21 is low and fuel consumption is poor.
Specifically, in the case where a pod propulsion device having a propulsive force with a first propeller at the front and a pod propulsion device having a second propeller at the rear is used exclusively as a rudder, for example, a fish school in a fishing boat May be searched. In such a case, the captain is focused on tracking the school of fish instructed by the fisherman, so he cannot concentrate on subtle operations such as simultaneously controlling the output of the main engine and electric motor, Therefore, the second propeller at the rear side applies a low torque of, for example, about 15% including the above-mentioned meaning of preventing chattering. However, as shown in this example, one stage of the limiter 26 is selected and about 30%. If the torque limit of the low load state is applied, the master can achieve better fuel efficiency than before even if the ship maneuvered by only the control adjustment of the main engine.
Further, as another specific example in which the pod propulsion device having a propulsive force with the first propeller at the front and the pod propulsion device having the second propeller at the rear is used exclusively as a rudder, for example, the sea is rough. The situation may be concentrated on steering. Even in such a case, as in the case of fish school search on a fishing boat, it is impossible to concentrate on a delicate operation such as performing output control of the main engine and the electric motor at the same time, so the second propeller on the rear side prevents chattering as described above. For example, a torque as low as 15% is applied. However, if one stage of the limiter 26 is selected and a torque limit in a low load state of about 30% is applied as in the present example, Similarly, even if the captain concentrates on the control adjustment only for the main engine, he can achieve better fuel efficiency than before. In any case, there is no worry of cavitation at low load.
Therefore, in the marine propulsion device 1 of the present example, when a marine vessel maneuvering method is employed in which the first propeller 4 in front is driven by the main engine 9 and the pod propulsion device 5 of the electric motor 15 is exclusively used as a rudder, In the torque control of the electric motor 15, the limiter 26 is set to one or two stages, the torque applied to the second propeller 6 at the rear is raised to the maximum torque limit, and thereby the auxiliary engine 20 that drives the generator 21 is optimized. Driving in a loaded state is preferable for improving fuel efficiency.

  FIG. 7 shows that in the torque control of the electric motor 15, the power demand on the ship is relatively small at about 30%, and the total power amount and the auxiliary engines 20 (power generation auxiliary machines) when the pod propulsion device 5 is exclusively used as a rudder. 1 and 2), the left diagram shows a case where no limit is limited, and the right diagram shows a case where one or two stages of the limiter 26 are selected in this example.

  When the limit restriction shown in the left diagram of FIG. 7 is not performed, the power consumption of the electric motor 15 is low, so that the total power is less than half of the power generation capacity (allowable limit) of one generator 21. The first unit is driven in a low load region of about 50%. For this reason, fuel consumption is low, and each auxiliary engine 20 is also worn out.

  As shown in the right diagram of FIG. 7, when the limit is limited in this example, the power consumption of the electric motor 15 is set higher, so the total power is the power generation capacity (allowable limit) of one generator 21. Therefore, the auxiliary engine 20 that is driven is only the first unit, and is driven at an optimal load state of about 80%. For this reason, fuel consumption is good and the wear of each auxiliary engine 20 is small.

  Thus, in the ship maneuvering method in which the first propeller 4 in front is driven by the main engine 9 and the pod propulsion device 5 of the electric motor 15 is exclusively used as a rudder, the limit is limited as shown in the right diagram of FIG. Since the torque applied to the rear second propeller 6 is larger than that during constant low torque control when the limit is not limited, the boat speed increases, but the front first propeller 4 is driven. The ship speed can be controlled by reducing the output of the main engine 9. Moreover, the fuel consumption as a whole is not deteriorated.

  In this example, the inverter 23 shown in FIG. 1 can control the rotational speed of the electric motor 15 as well as the torque control described above. In the rotational speed control, the inverter 23 that has received the drive command signal from the lever 25 gives the corresponding rotational speed command signal to the electric motor 15 so that the electric motor 15 is driven by feedback control at the commanded rotational speed. This is a control method.

  As shown in FIG. 1, a control state changeover switch 30 is provided in the alarm panel 24 provided with the limiter 26. If the control state changeover switch 30 is switched, a control state command signal corresponding to the switched control mode is input to the inverter 23, the inverter 23 shifts to the designated control mode, and the control mode of the inverter 23 is changed to torque control and rotation. Any number control can be set.

The control state changeover switch 30 has a function of alternatively closing a torque contact and a rotation contact connected in parallel to the drive command signal output from the lever 25.
When the control state changeover switch 30 is set to torque control, only the torque contact shown in FIG. 1 is closed, and the drive command signal from the lever 25 is limited via the closed torque contact. 26, the torque limit of the stage selected by the limiter 26 is added and sent to the inverter 23 to be used for torque control.

  When the control state changeover switch 30 is set to the rotational speed control, only the rotary contact is closed among the torque contact and the rotary contact shown in FIG. 1, and the drive command signal from the lever 25 passes through the closed rotary contact. Without being subjected to a torque limit, it is given to the inverter 23 as it is and used for rotational speed control.

  In the embodiment described above, the total electric energy is controlled so as not to exceed a predetermined allowable limit. As the predetermined allowable limit, an allowable amount of electric power that can be generated by one generator 21 is set. A limit was set. However, the predetermined permissible limit does not necessarily need to be the amount of power of one generator 21, for example, the total amount of power of two generators 21 is the predetermined permissible limit, and the third and subsequent units Limit control that suppresses starting of the auxiliary engine 20 may be performed.

Further, in the embodiment described above, the torque control by the limiter 26 has two stages of one stage and two stages. However, a torque limit can be set in any plural stages of three stages or more, and a volume or the like can be set. The torque limit may be adjusted steplessly using the adjusting means.
In the embodiment described above, each torque limit in the first stage and the second stage of the limiter 26 is defined in accordance with the ratio of the power in the ship to the total power amount, but the electric motor power in the total power amount. It can also be defined corresponding to the ratio of. For example, when a large amount of electric power is expected to be consumed by the electric motor, a torque limit is set so that about 70% of the amount of electric power that can be generated by one generator 21 can be used by the electric motor. When it is expected that less power is generated, about 30% of the amount of power that can be generated by one generator 21 can be used by an electric motor.

As described above, according to the marine propulsion device 1 of this example, the following effects can be obtained.
That is, in the marine propulsion device of the tandem and hybrid type counter-rotating system, the electric motor 15 that drives the rear propeller 6 is controlled by the torque control of the inverter 23, so that regeneration does not occur and the burden on the operator is reduced. The Further, since the range in which the load balance between the front propeller 4 and the rear propeller 6 can be set so as to increase the propulsion efficiency is widened, the adjustment work becomes easy, and it is not necessary to readjust frequently during the maneuvering. Further, according to the torque control, the load on the rear propeller 6 does not fluctuate greatly even if there is a sudden load fluctuation depending on the navigation situation, the fuel rack of the fuel injection device is less likely to cause hunting or jiggle, and the parts are worn. It becomes difficult to do.

  Further, in the torque control, since a control to give a constant torque limit to the drive command signal given to the inverter 23 is performed, the total power amount is limited within the range of power that can be generated by one generator 21, Only one auxiliary engine 20 is driven in an optimal load state to improve fuel efficiency, and wear of the auxiliary engine 20 due to driving in a low load region can be avoided.

  Further, in the case of adopting a boat maneuvering method in which the pod propulsion device 5 having the rear propeller 6 is exclusively used as a rudder, a constant is applied to the rear propeller 6 to prevent chattering from occurring in the drive system of the rear propeller 6. When applying low torque, chattering can be prevented by driving one generator 21 that covers this power consumption in an optimal load state with good fuel consumption and suppressing the output of the front propeller 4 driven by the main engine 9. As a result, the overall effect of improving fuel efficiency can be obtained.

  Further, since the torque limit given to the drive command signal in the limiter 26 is set in a plurality of stages according to the ratio of the power in the ship to the total power, the torque limit can be selected according to the actual demand for power in the ship. Regardless of which stage is selected, one auxiliary engine 20 can be driven in an optimal load state with good fuel efficiency, and an effect of improving fuel efficiency can be obtained. Note that the amount of power consumed in the ship increases and the output of the electric motor 15 decreases, so the load on the main engine 9 may be increased to increase the thrust by the propeller 4 in the front. The effect is obtained.

  In addition, since the control mode of the electric motor 15 by the inverter 23 can be arbitrarily switched to either torque control or rotation speed control, the control of the electric motor 15 is performed in a ship maneuvering situation where responsiveness is particularly required. The object can be achieved by switching the mode from torque control to rotational speed control.

DESCRIPTION OF SYMBOLS 1 ... Marine propulsion apparatus 2 ... Hull 3 ... Stern 4 ... 1st propeller (front propeller)
5 ... Pod propulsion device 6 ... Second propeller (rear propeller)
DESCRIPTION OF SYMBOLS 9 ... Main engine 15 ... Electric motor 20 ... Auxiliary engine 21 ... Generator 23 ... Inverter 24 ... Alarm panel 26 ... Limiter 30 ... Control state changeover switch

Claims (3)

A first propeller provided at the stern of the hull;
A main engine provided on the hull for driving the first propeller;
The first propeller and the counter-rotating propeller are configured outside the stern of the hull so as to face the first propeller, and the swivel is pivotable about a swivel axis parallel to the vertical direction. A second propeller attached to the hull;
An electric motor provided on the hull to drive the second propeller;
A plurality of generators provided on the hull for supplying electric power to the electric motor, and a plurality of auxiliary engines for driving the plurality of generators, respectively,
Yes, and the torque control for driving the electric motor by the command torque to a propulsion device for a row cormorants舶 by inverters,
In the torque control, by giving a constant torque limit to the drive command signal given to the inverter, the total electric power that is the sum of the electric power of the electric motor and the electric power in the ship is controlled so as not to exceed a predetermined allowable limit. A marine propulsion device characterized by that. The torque limit given to the drive command signal is defined by a ratio of electric power of the electric motor or a ratio of electric power in the ship in the total electric power, and the ratio is set in a plurality of stages. The marine propulsion device according to claim 1 , wherein the torque limit can be arbitrarily set by selecting the ratio according to demand. The inverter has a function of performing rotation speed control for driving the electric motor at a commanded rotation speed, and sets the control mode of the electric motor by the inverter to either the torque control or the rotation speed control. marine propulsion device according to claim 1 or 2, characterized by being configured to allow.

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