JP2011025799A - Power feeding system and electric propulsion ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power feeding system which is high in energy efficiency and can cope with a rapid load variation, and an electric propulsion ship. <P>SOLUTION: The system includes target loads 1 requiring power, a plurality of generators 2 for supplying power to the target loads 1, drive sources 3 for driving the respective generators 2, rechargeable batteries 4 for accumulating the power generated by the generators 2, and a control means 5 for controlling the distribution of the power generated by the generators 2 and the charge and discharge of the rechargeable batteries 4. The control means 5 controls the number of generators 2 which are driven based on workloads of the target loads 1, and, until the number of generators 2 required for the workloads of the target loads 1 are driven after the number of driven generators 2 becomes deficient with respect to the workloads of the loading target 1, the control means supplies the power to the target loads 1 by using the rechargeable batteries 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply system and an electric propulsion ship using a plurality of generators, and more particularly to a power supply system and an electric propulsion ship that can cope with a sudden load fluctuation.

  In recent years, electric propulsion ships have attracted attention from the viewpoint of reducing environmental loads and ease of speed control (see, for example, Patent Document 1 and Patent Document 2). For a ship with a relatively long navigation distance such as a ferry or a tanker, the operation schedule is determined in advance, and in general, the ship is operated in accordance with the operation schedule of departure from port → speed increase → steady operation → deceleration → call at the port. In such a ship, there is little sudden load fluctuation, and it is only necessary to control the power feeding system according to the planned operation schedule, and there is a great merit of making it an electric propulsion ship.

  Here, the electric propulsion ship described in Patent Document 1 is configured such that a capacitor (storage battery) is arranged in a power supply system so that it can be used for preliminary propulsion and for inboard supply. Moreover, the electric propulsion ship described in Patent Document 2 is configured to be used as an emergency in the case where a storage battery is disposed in a power feeding system and a generator fails.

JP 2008-24187 A Japanese Patent Laid-Open No. 11-266532

  On the other hand, dredgers, unloading dredgers, structure building ships, tugboats and tugboats, transportation auxiliary ships such as transportation ships, survey ships such as survey ships, environmental recovery ships such as oil recovery ships, special work ships, etc. The so-called work boats and boats for fishing use have been changed from diesel propulsion vessels that use diesel engines as the main engine to electric propulsion vessels because the operation schedule is not fixed and the control of the power feeding system is complicated, and it is desirable to reduce construction costs. Switching is delayed.

  For example, in a so-called tugboat, the waiting time for waiting for instructions is long, and the diesel engine is forced to operate at a low load. Here, FIG. 5 is a diagram showing the relationship between the engine load factor of the tugboat and the operating time rate. The horizontal axis represents the engine load factor (%), and the vertical axis represents the operating time rate (%). The data shown in FIG. 5 is the result of measuring the operational status of the tugboat for 30 days. As shown in FIG. 5, the tug boat is often used in a state where the engine load factor is 20% or less, and the average engine load factor is about 16%. The low-load operation of a diesel engine is inefficient in energy and tends to cause incomplete combustion of the fuel, resulting in a high environmental load. In addition, there are many occasions that require rapid load fluctuations such as sudden start and rapid acceleration from low load operation to maximum operation load, and further, energy efficiency is poor and environmental load becomes high.

  The present invention has been devised in view of the above-described problems, and an object thereof is to provide a power supply system and an electric propulsion ship that are high in energy efficiency and can cope with sudden load fluctuations.

  According to the present invention, a load object that requires electric power, a plurality of generators that supply electric power to the load object, a drive source that drives each of the generators, and an electric power generated by the generator are stored. A power supply system comprising: a secondary battery; and a control unit that controls distribution of electric power generated by the generator and charging / discharging of the secondary battery, wherein the control unit generates the power generation according to the work load. While controlling the number of driven machines, until the number of driven generators necessary for the load target work is driven after the number of driven generators is insufficient for the load target work, A power supply system is provided, wherein power is supplied to the load target by the secondary battery.

  The control means drives the number of generators required for the load target work after a certain period of time has elapsed when the number of generators driven is insufficient for the load target work. It may be configured. In addition, the control unit stops the generators of the number of drive units unnecessary for the load target work amount after a certain period of time has elapsed in which the number of drive generators exceeds the load target work amount. It may be configured as follows.

  The control means is configured to drive the required number of the generators and distribute the surplus power to the charging of the secondary battery when the charging rate of the secondary battery falls below a first reference value. May be. Further, when the charging rate of the secondary battery exceeds a second reference value that is higher than the first reference value, the control means stops the number of generators that are not required for the load target work. However, the secondary battery may be configured to be charged.

  The control unit may be configured to stop the power supply to the load target after switching the power supply to the load target from the generator to the secondary battery.

  Moreover, the said electric power feeding system is used for the electric propulsion ship by which the load object is comprised by the screw for ship propulsion and the electric motor which drives this screw, for example. Furthermore, the control means may be configured to charge the secondary battery by supplying power from the land side when the electric propulsion ship is anchored.

  According to the power supply system and the electric propulsion ship of the present invention described above, the secondary battery can supply the insufficient power generated in the time lag until the required generator is started up, so that the maximum operation from the sudden start or low load operation can be achieved. It is possible to smoothly cope with sudden load fluctuations such as sudden acceleration to the load. In addition, by controlling the number of generators to be driven according to the workload of the load target, it is possible to improve the energy efficiency of the power feeding system, and it is a load target that is likely to be forced to operate at a low load like a tugboat. Can be operated efficiently, and the environmental load can be reduced. Furthermore, since the secondary battery is charged with surplus power generated when the unnecessary generator is stopped, it is possible to effectively control the number of generators driven and charge / discharge the secondary battery.

It is a whole lineblock diagram showing the electric supply system concerning the present invention. It is a figure which shows the effect | action of a control means, (A) shows the relationship between a ship load factor, the number of generator drive, and charging / discharging of a secondary battery, (B) has shown the storage battery charging rate. FIG. 3 is a partial detail view in FIG. 2, (A) shows the A part, (B) shows the B part, (C) shows the C part, (D) shows the D part, and (E) shows the E part. It is a figure which shows the modification and application example of the electric power feeding system which concern on this invention, (A) is a 1st modification, (B) is a 2nd modification, (C) has shown the application example. It is a figure which shows the relationship between the engine load factor of a tugboat and an operation time rate.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is an overall configuration diagram showing a power feeding system according to the present invention.

  As shown in FIG. 1, a power supply system of the present invention includes a load target 1 that requires power, a plurality of generators 2 that supply power to the load target 1, and a drive source 3 that drives each generator 2. The secondary battery 4 that stores the power generated by the generator 2 and the control means 5 that controls the distribution of the power generated by the generator 2 and the charging / discharging of the secondary battery 4, The number of drives of the generator 2 is controlled according to the work load of the load target 1, and the drive required for the work load of the load target 1 after the drive number of the generator 2 is insufficient with respect to the work load of the load target 1 The secondary battery 4 is configured to supply power to the load target 1 until the number of generators 2 is driven.

  The load target 1 is a device that receives power supply and works to the outside. In the embodiment shown in FIG. 1, the load target 1 includes a ship propulsion screw S and an electric motor M that drives the screw S. Here, the case where there are two load targets 1 (for example, the case where the screw S is arranged on each of the port side and starboard side) is illustrated, but the load target 1 may be one, or three or more. There may be.

  The generator 2 is a device that converts power into electric power. Here, an AC generator is used as the generator 2, but a DC generator may be used. The larger the number of generators 2 installed, the more detailed control of the number of operating units can be performed, but the total number of generators 2 is determined by comprehensively considering the arrangement space and the operating mode. In addition, devices such as a control unit 5, a transformer 22, a power converter 23, and a charge / discharge device 24 are arranged in the power supply line 21 on the downstream side of the generator 2. The power converter 23 is a device that controls power supply to the power load target 1 and charge / discharge of the secondary battery 4 while appropriately converting AC / DC. The charging / discharging device 24 is a device that controls charging / discharging of the secondary battery 4 while appropriately converting AC / DC.

  For example, an internal combustion engine such as a diesel engine is used as the drive source 3. In the present invention, even when a diesel engine is used as the drive source 3, the diesel engine is connected to each of the plurality of generators 2, thereby driving a ship propulsion screw by one diesel engine. Compared with the conventional system, the output of a diesel engine per vehicle can be lowered. Further, since the surplus power is charged in the secondary battery 4 and the insufficient power can be supplemented by the secondary battery 4, it is necessary to vary the output of the diesel engine in accordance with the load variation of the load target 1. It is possible to operate in a state close to the rating. Therefore, the energy efficiency of the diesel engine can be improved and the environmental load can be reduced. The drive source 3 may be a steam turbine, wind power generation, thermal power generation, hydroelectric power generation, solar power generation, or the like.

  The secondary battery 4 is a device that charges surplus power generated by the generator 2 or replenishes the insufficient power of the load target 1. As the secondary battery 4, various types of batteries such as a lead storage battery, a nickel / hydrogen storage battery, and a lithium ion secondary battery can be used. For example, the secondary battery 4 is connected to the power conversion device 23 and the charge / discharge device 24 in the power supply line 21 as shown in the figure. The charging / discharging of these secondary batteries 4 is processed by the power conversion device 23 and the charging / discharging device 24 based on the command of the control means 5. Here, both the secondary battery 4 connected via the power conversion device 23 and the secondary battery 4 connected via the charging / discharging device 24 are illustrated, but the number of connected secondary batteries 4 and the connection are also shown. The location is determined by the capacity of the secondary battery 4 or the like, and a part of the secondary battery 4 in the power supply line 21 distributed to the load target 1 may be omitted, or the power supply line distributed to the load target 1 The secondary battery 4 may be omitted by connecting the secondary battery 4 to a part or all of the power supply 21 and connected via the charging / discharging device 24. Alternatively, the secondary battery 4 in the power supply line 21 distributed to the load target 1 may be omitted. The secondary battery 4 may be omitted and only the secondary battery 4 connected via the charging / discharging device 24 may be used.

  The control means 5 is a device that controls distribution of electric power generated by the generator 2, charge / discharge of the secondary battery 4, optimization of the number of generators 2 driven, and the like. The control means 5 is a so-called switchboard and control panel (or control computer), and may be configured integrally as illustrated or may be configured separately. The control means 5 is configured to supply power to the load target 1 and also to supply power to the ship.

  Here, FIG. 2 is a figure which shows the effect | action of a control means, (A) shows the relationship between an inboard load factor, the number of generator drive, and charging / discharging of a secondary battery, (B) shows a storage battery charging rate. Show. In FIG. 2 (A), the solid line shows the fluctuation of the ship load factor, and the alternate long and short dash line shows the fluctuation of the number of generators driven. The inboard load factor means the sum of the load target 1 and the load factors of the inboard power supply (the ratio of the load to the maximum load amount).

  As shown in FIG. 2A, all the generators 2 are set to be driven when the inboard load factor is 100%. In the embodiment shown in FIG. In this case, control is performed so as to bear an inboard load factor of 25% per generator 2. Therefore, in the power supply system using N generators 2, each generator 2 is controlled so as to bear a ship load factor of (100 / N)%. The control means 5 basically drives the two generators 2 when the inboard load factor exceeds 25% and controls the three generators 2 when the inboard load factor exceeds 50%. The four generators 2 are driven when the inboard load factor exceeds 75%. That is, the control means 5 is configured to control the number of driven generators 2 according to at least the workload of the load target 1.

  Further, the control means 5 basically has insufficient power in the load target 1 when the inboard load factor (solid line) exceeds the number of generators driven (dotted line) (shaded area in the figure). When power is supplied from the secondary battery 4 to the load target 1 and the inboard load factor (solid line) falls below the number of generators driven (dashed line), surplus power is generated in the power supply system. Therefore, the switch 41 and the like are controlled so as to charge the secondary battery 4. That is, the control means 5 is at least from the time when the number of driven generators 2 is insufficient with respect to the workload of the load target 1 until the number of generators 2 required for the load of the load target 1 is driven. The secondary battery 4 is configured to supply power to the load target 1.

  Hereinafter, based on FIG.2 and FIG.3, the effect | action of the control means 5 is demonstrated in time series. Here, FIG. 3 is a partial detailed view in FIG. 2, (A) is A part, (B) is B part, (C) is C part, (D) is D part, (E) is E part. , Shows.

  First, as shown in FIG. 2 (A), it is preferable to start up at least one generator 2 before starting power to the load target 1 or the like. This is because a certain time lag (for example, about several minutes) is required until the generator 2 is started up to reach the rated operation state. Of course, the required number of generators 2 may be started simultaneously with the start of power, and power may be supplied by the secondary battery 4 during the time lag.

  Now, since the inboard load factor until time t1 is 25%, one generator 2 is driven until time t1. Then, as shown in FIG. 3A, after a time x1 has elapsed from time t1 when the inboard load factor reaches 50%, the second generator 2 is started up. Further, after the time x1 has elapsed from the time when the inboard load factor reaches 75%, the third generator 2 is started up. Here, the time x2 is a time lag until the generator 2 enters the rated operation state. Therefore, the second generator 2 starts the rated operation after the time (x1 + x2) has elapsed from the time t1, and the third unit starts the rated operation slightly later than that. That is, the control means 5 drives the number of generators 2 required for the work of the load target 1 after a certain period of time has elapsed when the number of drives of the generator 2 is insufficient for the work of the load target 1. It is configured to let you.

  Further, since the inboard load factor up to time t2 is in the range of 50 to 75%, three generators 2 are driven up to time t2. Then, as shown in FIG. 3 (B), after the time y1 has elapsed from the time t2 when the inboard load factor has decreased to 50%, one generator 2 is stopped. Further, after the time y1 has elapsed from the time when the inboard load factor has decreased to 25%, the other generator 2 is stopped. That is, the control means 5 stops the generators 2 whose number of drives is unnecessary for the work of the load target 1 after a certain period of time has elapsed when the number of drives of the generator 2 exceeds the work of the load target 1. It is configured to let you. In addition, since the ship load factor finally settled in the range of 0 to 25% here, electric power is supplied by one generator 2.

  After that, the inboard load factor temporarily increased rapidly, and the inboard load factor reached 25% at time t3 and further exceeded 50%. As shown in FIG. On the other hand, since the time when the number of generators driven is insufficient is shorter than the time x1, the insufficient power is supplied by the secondary battery 4 without driving the generator 2. The set time of the time x1 varies depending on the nature of the load target 1 and the usage environment. When the ship load factor data is acquired and insufficient power is supplied by the generator 2, it is supplied by the secondary battery 4. It is preferable to distinguish between cases and calculate and set the boundary value, but it may be set based on the experience of the operator. The time x1 is set to a time of about several tens of seconds, for example.

  In addition, the inboard load factor temporarily increased rapidly, and the inboard load factor reached 25% at time t4 and further exceeded 50%. However, as shown in FIG. When the vertical movement is repeated and finally converges within the range of 25 to 50%, the time when the inboard load factor exceeds 25% exceeds the time x1, and the time when the inboard load factor exceeds 50% However, since the time x1 is not exceeded, only one generator 2 is additionally driven.

  As shown in FIG. 3E, when the secondary battery charging rate falls below the first reference value α at time t5, the surplus is generated by driving the required number of generators 2 (here, four). Electric power is distributed to the charging of the secondary battery 4, and rapid charging is performed. The required number of generators 2 to be driven at the time of the quick charging is a number that can generate surplus power while supplementing the inboard load factor at time t5 with the generator 2. Moreover, quick charge can be performed by increasing the number of drives so that more surplus power is generated. In such a control state, each generator 2 is driven immediately at time t5 regardless of the numerical value of the inboard load factor. At this time, a time lag of time x2 occurs, so that the insufficient power during this time is supplied from the secondary battery 4. Therefore, the first reference value α is the maximum underpower (time x2 × inboard load factor 100%) that can be generated when all the generators 2 are started up at the same time from a state where there is no generator 2 being driven. It must be set so that it can be charged with power that can compensate for the area of In other words, the first reference value α must be set so that the lower limit value γ of the secondary battery charging rate does not become 0 in any case.

  Then, when the secondary battery charging rate exceeds a second reference value β higher than the first reference value α, the number of generators 2 that are unnecessary for the work load 1 is stopped. In FIG. 3 (E), since the inboard load factor at time t6 when the secondary battery charging rate exceeds the second reference value β is within the range of 0 to 25%, only one generator 2 is required. Therefore, there are three unnecessary generators 2, and the driving of the three generators 2 is stopped.

  2A, when the charging rate of the secondary battery 4 is sufficiently high (eg, the second reference value β or more) and the inboard load factor is low (eg, 25% or less). Alternatively, all the generators 2 may be stopped and power may be supplied only by the secondary battery 4. In this case, the generator drive number control based on the time x1 is set not to operate.

  Also, as shown in part G of FIG. 2 (A), when power supply to the load target 1 is stopped, all the generators 2 are stopped so that unnecessary power is not generated. 1 may be switched from the generator 2 to the secondary battery 4 to stop the power supply to the load target 1. Also in this case, the generator drive number control based on the time x1 is set not to operate. Further, the time t7 at which all the generators 2 are stopped is predicted by the product of the remaining time until the time t8 at which the power supply to the load target 1 is stopped and the inboard load factor that will be required thereafter. Since the secondary battery 4 needs to be charged with power sufficient to supplement the power, the secondary battery charging rate and the remaining time until time t8 are monitored. In this case, the secondary battery charging rate control based on the first reference value α is not activated.

  According to the above-described embodiment of the power supply system according to the present invention, the insufficient power generated in the time lag (time x2) until the required generator 2 starts up can be supplied by the secondary battery 4, and sudden start and low load can be achieved. It is possible to respond smoothly and quickly to sudden load fluctuations such as sudden acceleration from driving to maximum driving load. In addition, by controlling the number of generators 2 to be driven according to the work amount of the load target 1, it is possible to improve the energy efficiency of the power feeding system, and the load target 1 that is easily forced to perform low-load operation like a tugboat. Even so, the vehicle can be operated efficiently and the environmental load can be reduced. Furthermore, the surplus power generated when the unnecessary generator 2 is stopped is charged in the secondary battery 4, thereby effectively controlling the number of driven generators 2 and charging / discharging the secondary battery 4. Can do.

  The generator 2 has a total capacity equivalent to an onboard load factor of 100%, and an imbalance with the amount of power generated by the generator 2 being driven occurs due to a sudden load fluctuation imposed on the load target 1. In addition, the secondary battery 4 is discharged during the start-up time of the generator 2 (power supply to the load target 1 and the like), and the secondary battery 4 is charged during the stop time of the generator 2, thereby By avoiding sudden load fluctuations in the machine 2, it is possible to keep the operating state with the optimal number of operating units and operating loads as long as possible. Furthermore, compared with a conventional system in which a part of the inboard load factor is simply supplemented with a storage battery, the required capacity of the secondary battery 4 can be kept low, and the construction cost and installation space can be reduced.

  Next, modified examples and application examples of the power feeding system according to the present invention will be described. Here, FIG. 4 is a figure which shows the modification and application example of the electric power feeding system which concern on this invention, (A) is a 1st modification, (B) is a 2nd modification, (C) is an application example, Is shown. In addition, the same code | symbol is attached | subjected about the same component as embodiment shown in FIG. 1, and the overlapping description is abbreviate | omitted.

  In the first modification of the power feeding system shown in FIG. 4A, the load target 1 is composed of a single ship propulsion screw S and a plurality of electric motors M that drive the screw S. As described above, the power feeding system of the present invention can be applied to an electric propulsion ship having one screw S, and the same effects as those of the above-described embodiment can be obtained. In the first modified example, it is necessary to control how much power is supplied from which electric motor M to the screw S, but such control may be performed by the control means 5 described above. You may make it carry out by the control apparatus arrange | positioned separately. Although not shown, the load target 1 has a plurality of screws S (for example, two) and a plurality of electric motors M (for example, three), and the power is distributed by the plurality of electric motors M to each of them. It may be configured to be transmitted to the screw S.

  The 2nd modification of the electric power feeding system shown to FIG. 4 (B) has shown the case where the load object 1 is the other electric power consumption apparatus 6 used other than an electric propulsion ship. The load target 1 is, for example, a cargo handling machine such as a crane or an unloader, a construction machine such as an excavator or a transport machine, a pump used in a plant or factory, an air conditioner, a transport facility, an industrial machine facility, or the like. Here, the configurations of the two generators 2, one secondary battery 4, and one power consuming device 6 are illustrated, but a plurality of secondary batteries 4 may be arranged as in the first modification. Alternatively, a plurality of power consuming devices 6 may be connected.

  The application example of the power feeding system shown in FIG. 4C illustrates an electric propulsion ship 7 to which the embodiment shown in FIG. 1 is applied. In such an application example, the load target 1 is configured by a pod-type propulsion device including a screw S and an electric motor M. Further, the generator 2 and the drive source 3 are stacked in a plurality of stages. In such an electric propulsion ship 7, the capacity and size per drive source 3 is smaller than that of a conventional diesel propulsion ship, and the connection (feeding line 21) of each component downstream of the generator 2 is wired by an electric wire. For reasons such as being possible, the degree of freedom of arrangement of each component is high, and the dead space can be reduced. Further, when the electric propulsion ship 7 is anchored at the quay, the secondary battery 4 may be charged while supplying electric power from the land side by the control means 5 and supplying power to the ship. When power can be supplied from the land side in this way, the secondary battery 4 can be charged without wastefully driving the generator 2 even when the charging rate of the secondary battery 4 at the time of berthing is low. In addition, it is possible to smoothly cope with high-load operation immediately after the start of work of the electric propulsion ship 7.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Load object 2 ... Generator 3 ... Drive source 4 ... Secondary battery 5 ... Control means 6 ... Electric power consumption apparatus 7 ... Electric propulsion ship 21 ... Feed line 22 ... Transformer 23 ... Power converter 24 ... Charging / discharging device

Claims (8)

A load target that requires power; a plurality of generators that supply power to the load target; a drive source that drives each of the generators; a secondary battery that stores the power generated by the generator; and the power generation In a power supply system having a control means for controlling distribution of electric power generated by the machine and charging / discharging of the secondary battery,
The control means controls the number of driven generators in accordance with the load target work, and the load target work after the number of generators driven is insufficient with respect to the load target work. A power supply system, wherein power is supplied to the load target by the secondary battery until the number of generators required for the quantity is driven.   The control means drives a generator having the number of drives required for the load target work after a certain period of time has passed since the state where the number of generators driven is insufficient with respect to the load target work. The power feeding system according to claim 1.   The control means stops the generators of the number of drive units unnecessary for the load target work amount after the state in which the number of drive units of the generator exceeds the load target work amount passes for a certain period of time. The power supply system according to claim 1, wherein the secondary battery is charged.   When the charging rate of the secondary battery falls below a first reference value, the control means drives the required number of the generators to distribute surplus power to the charging of the secondary battery. The power feeding system according to claim 1.   The control means, when the charging rate of the secondary battery exceeds a second reference value that is higher than the first reference value, to stop the number of generators that are unnecessary for the load target work, The power feeding system according to claim 4.   The power supply system according to claim 1, wherein the control unit switches power supply to the load target from the generator to the secondary battery, and then stops power supply to the load target.   An electric propulsion system comprising the power feeding system according to any one of claims 1 to 7, wherein the load target includes a ship propulsion screw and an electric motor that drives the screw. ship. The electric propulsion ship according to claim 7, wherein, when the electric propulsion ship is anchored, the control unit supplies electric power from the land side to charge the secondary battery.