JP6542065B2 - Ship propulsion system with exhaust heat recovery system - Google Patents

Description

  The present invention relates to a ship propulsion system provided with an exhaust heat recovery system capable of stopping operation control of an axial generator / motor when switching between the assist operation and the power supply operation can not be performed.

  JP-A-2009-535258 (Patent Document 1) includes a turbine and a generator for supplying electric energy using waste heat as an energy source, and an exhaust heat for supplying electric energy generated by the generator to an electric network in the ship. A recovery system and an axial generator / motor connected to a propeller shaft are provided, and surplus electric power generated by the generator is supplied to the electric network, and surplus electric power is supplied to the axial generator / motor to supply surplus electric power. By converting it into mechanical energy for driving the propeller shaft, an assist operation is performed to assist the propulsion of the ship by the propeller shaft, and when the surplus power disappears, the shaft generator / motor is driven by the propeller shaft as a shaft generator. The power supply operation to supply the generated electrical energy to the electrical network is performed, and when the switching signal is input A ship propulsion assist system having a switching function to switch the electric and motor from the shaft generator to the motor or from the motor to the shaft generator, switching from the motor operation of the shaft generator and motor to the generator operation and generating power from the motor operation An example of a ship propulsion system with an exhaust heat recovery system is disclosed that performs a switch to machine operation without the intervention of a power management system.

  In addition, as a switching signal generation system that can be used to generate a switching signal, a control signal generation unit for giving a control signal to a controller of a shaft generator / motor, output power output from a shaft generator / motor and a shaft generator / motor Switching the shaft generator / motor from the shaft generator to the motor or from the motor to the shaft generator based on the input power input to the control unit and a control signal (a governor signal) given to the control unit for the shaft generator / motor A system comprising a switching signal generation unit for outputting a signal is sold by Taiyo Electric Co., Ltd. under the product number of SGH105BS-20. In this system, the switching signal generation unit generates a control signal until the output power or input power becomes 0 kW after the output power or input power of the shaft generator / motor becomes smaller than the predetermined switching preparation power. And a switching signal output unit for outputting a switching signal when a switching preparation time which has been determined in advance is passed.

Japanese Patent Publication No. 2009-535258

  However, as in the conventional switching signal generation system, as a control signal (i.e. governor signal) of the shaft generator and motor, the pulse width is gradually or stepwise shortened when switching from the shaft generator to the motor or from the motor to the shaft generator. If such a control signal is provided, it takes a considerably long time for the predetermined cumulative time to reach the predetermined switching preparation time, which causes a problem that rapid switching can not be performed. In addition, when the switching signal is not output from the switching signal output unit due to disconnection or failure, the switching operation can not be performed.

  An object of the present invention is to enable generation of a switching signal quickly even when an existing switching signal generation system is adopted, and further, when the switching signal is not output due to disconnection or failure, etc. It is an object of the present invention to provide a ship propulsion system provided with an exhaust heat recovery system capable of stopping the switching operation of the above.

  The ship propulsion system provided with the exhaust heat recovery system according to the present invention comprises a turbine and a generator that supply electric energy using exhaust heat as an energy source, and an exhaust that supplies electric energy generated by the generator to an electric network in the ship. It has a heat recovery system and a ship propulsion assist system. The ship propulsion assist system includes an axial generator / motor coupled to a propeller shaft, and supplies surplus electric power remaining to the axial generator / motor even if the electric energy generated by the generator is supplied to the electric network. By converting the power into mechanical energy for driving the propeller shaft, an assist operation is performed to assist the propulsion of the ship by the propeller shaft, and when there is no surplus power, the propeller shaft is used as the shaft generator / motor as a shaft generator. Power supply operation to supply the generated electric energy to the electric network, and it has a switching function to switch the shaft generator and motor from the shaft generator to the motor or from the motor to the shaft generator when the switching signal is input ing. Furthermore, the ship propulsion system provided with the exhaust heat recovery system according to the present invention can be gradually or stepwise switched when switching from the shaft generator to the motor or from the motor to the shaft generator in the drive control device for the shaft generator and motor. A control signal generating unit for giving a control signal with a shortened pulse width; a power measuring unit for measuring output power output from the shaft generator / motor and input power input to the shaft generator / motor; And a switching signal generation unit for outputting a switching signal for switching the shaft generator / motor from the shaft generator to the motor or from the motor to the shaft generator based on the output and the control signal. The switching signal generation unit accumulates and accumulates the input time of the control signal when the output power or the input power reaches 0 kW after the output power or the input power measured by the power measuring unit becomes smaller than the predetermined switching preparation power. An input time accumulation unit for storing the time and a switching signal output unit for outputting a switching signal when the accumulated time has passed a predetermined switching preparation time. In the present invention, the control signal generation unit outputs the control signal as a continuous signal for a predetermined time longer than the switching preparation time when the output power measured by the power measuring unit or the input power becomes smaller than the predetermined switching preparation power. After that, the output of the control signal is stopped. In this case, when performing the switching operation, since the continuous control signal is input to the input time accumulation unit, the cumulative time can be shortened in a shorter time than when the control signal having a short pulse width is input. Will be reached. Therefore, according to the present invention, using an existing switching signal generation system, a control signal that reduces the pulse width gradually or in stages when switching from an axial generator to a motor or from a motor to an axial generator. Even in the case of giving, after the output power or input power of the shaft generator / motor becomes smaller than the predetermined switching preparation power, accumulation time can be continuously accumulated by using the control signal as a continuous signal. . Therefore, the switching signal can be generated quickly. Even when disconnection or failure occurs in the switching signal generation unit and the switching signal is not output, the control signal as a continuous signal generated by the control signal generation unit stops at a predetermined time. As a result, even if the switching signal is not output, the control signal can be stopped to stop the switching operation of the shaft generator / motor.

  The switching preparation power is preferably a value in the range of 4% to 6% of the rated power. This is because if the switching preparation power is smaller than 4%, it takes a long time, and if it is larger than 6%, the load fluctuation becomes large. In this way, the switching operation of the shaft generator / motor can be smoothly performed without delay and without influence on the inboard frequency.

  The switching preparation time is preferably set as a time between 2 seconds and 4 seconds. The switching preparation time is based on a rule of thumb, and if the switching preparation time is too short, a malfunction of the switching operation tends to occur, and if the switching preparation time is long, a switching delay occurs.

It is a block diagram showing composition of one embodiment of a vessel propulsion system provided with an exhaust heat recovery system of the present invention. It is a flowchart which shows an example of the algorithm of the software used when implement | achieving the principal part of embodiment of FIG. 1 using a computer. FIG. 6 is a flow chart showing an algorithm of software used when executing the switching function of the shaft generator / motor using a computer. FIG. (A) is the output power when the shaft generator / motor measured by the power measuring unit is functioning as a generator or the input power when the shaft generator / motor is functioning as a motor (hereinafter referred to as output power or input A diagram used to explain the relationship of deviation between power and 0 kW, (B) shows an example of a conventional control signal (a governor signal), and (C) shows an example of implementing a switching function. It is a figure which shows the example of the control signal (governer signal) in a comparative example, and (D) is a control signal (governer signal) output from the control signal generation part at the time of implementing a switching function in embodiment of this invention. Is a diagram illustrating an example of It is a flowchart which shows an example of the algorithm of the software used when displaying the efficiency of an axial generator and motor on the display screen of a correlation display part. (A) is a figure which shows an example of a display of the rotation speed, output power or input power, and efficiency which are displayed on the display screen of a correlation display part, (B) demonstrates the example which utilizes the display of correlation. It is a figure used for. It is a flowchart which shows the algorithm of the software used when performing 0 kW control and mode control using a computer. While the generator and the shaft generator / motor are in parallel operation, the generator bears all inboard loads, and the shaft generator / motor always maintains 0 kW. While the generator and the shaft generator / motor are in parallel operation, the shaft generator / motor energizes the main generator of the surplus power of the generator and switches to the generator if the power of the generator is insufficient, and the inboard load of the shortage FIG. While the generator and shaft generator / motor are in parallel operation, the generator bears the maximum load of the ship and the shaft generator / motor load, and the shaft generator / motor boosts the main machine by the surplus power of the generator It is a figure which shows a mode that it carries out.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a ship propulsion system equipped with the exhaust heat recovery system of the present invention. FIG. 2 is a flow chart showing an example of an algorithm of software used when realizing the present invention using the main part computer of the embodiment of FIG. The flowchart of FIG. 2 assumes that the shaft generator / motor can be used as a motor.

  The ship propulsion system provided with the exhaust heat recovery system of the present embodiment includes an exhaust heat recovery system 1 and a ship propulsion assist system 3. The exhaust heat recovery system 1 includes a turbine 5 that supplies electric energy using exhaust heat as an energy source, and a generator (STG) 7 that is driven by the turbine 5 to generate electric power, and generates electric energy generated by the generator 7 Supply to the onboard electrical network 9.

  Although any generator can be used as the generator 7, in addition to the steam turbine (S / T) that recovers the thermal energy of the main exhaust gas and generates steam by the economizer to generate steam, the pressure energy of the exhaust gas itself is also used. It is preferable to use a combined power generation system combining a power turbine (P / T) that recovers and drives the The steam turbine S / T and the power turbine P / T have a turbine control system (Turbine Control System) as a control device capable of performing load sharing in accordance with the inboard power so that energy efficiency is optimized.

  The ship propulsion assist system 3 includes a shaft generator / motor (SGM) 13 connected to the propeller shaft 11. The ship propulsion assist system 3 supplies the surplus power remaining to the shaft generator / motor 13 even if the electric energy generated by the generator 7 is supplied to the electric network 9 to drive the propeller shaft 11 with the surplus power. By converting into mechanical energy, an assist operation is performed to assist the propulsion of the ship by the propeller shaft 11.

  The shaft generator / motor 13 is used as a system to generate electric power by converting rotational energy of the main machine into electric power, ie shaft power generator (SG), and supplies surplus energy to the main machine when surplus power is found in the ship's power supply. It is a system that can be used as an energizing system or motor (SM). Specifically, start-up is possible when the main machine rotational speed is, for example, 53 rpm or more, and the motor rating changes with the rotational speed. When the purpose is to improve fuel consumption, it is mainly used as a motor in a system that performs main machine energization, and main machine can be boosted with the generator 7 and the shaft generator / motor 13 operating in parallel.

  In the ship propulsion assist system according to the present embodiment, whether or not the frequency fluctuation range has become equal to or greater than a predetermined first value (for example, 0.2 Hz), and the frequency measurement unit 15 for measuring the frequency in the electric network 9 inside the ship. And the frequency fluctuation suppressing unit 19 that suppresses the frequency fluctuation by suppressing the assist operation when the frequency fluctuation width becomes equal to or more than a predetermined first value. . The frequency fluctuation suppressing unit 19 suppresses the frequency fluctuation by reducing the target load of the shaft generator / motor 13. Specifically, the frequency fluctuation suppressing unit 19 instructs the control signal generating unit 23 of the drive control device 21 that controls the drive of the shaft generator / motor 13 to reduce the target load. The control signal generation unit 23 has a pulse width gradually or stepwise when switching from the shaft generator to the motor or from the motor to the shaft generator in the drive circuit 25 of the drive control device 21 of the shaft generator / motor 13. A control signal [a control signal with variable pulse width (a governor signal)] to be shortened is provided.

  The frequency fluctuation suppressing unit 19 measures the frequency inside the ship (step ST1), and if the frequency fluctuation width in the electric network 9 becomes equal to or more than the first value due to reasons other than the assist operation (5 seconds in step ST2 in FIG. 2). If the determination of the 0.2 Hz drop performed once is Yes), the target load of the shaft generator / motor 13 is reduced to suppress the frequency fluctuation (step ST3). It is preferable that a predetermined limit (a hunting prevention limit) be provided for the amount of reduction per one cycle by the frequency variation suppression unit 19 (step ST4). In the present embodiment, since confirmation is performed once every five seconds in step ST2, it is possible to prevent the occurrence (hunting) of rapid frequency fluctuation if the reduction amount is limited. Incidentally, it is preferable to set the limit by this step ST4 to about 30% (for example, make the reduction amount 0% to 30%). The frequency fluctuation range judgment unit 17 and the frequency fluctuation suppression unit 19 are realized by steps ST1 to ST4 of the flowchart shown in FIG.

  Further, in the present embodiment, an available power amount calculation unit 27 for computing the possible power amount of the generator, a power amount limiting unit 28, and an inboard power measurement unit for measuring the inboard power used in the electrical network 9. 29. A surplus power calculation unit 31 that calculates surplus power by subtracting inboard power from the available power amount, and whether the surplus power value obtained by the surplus power calculation unit 31 is a positive value or a negative value The target power determining unit 35 determines the target load of the shaft generator / motor 13 based on the surplus power, and the first frequency fluctuation range in the electrical network increases with the target load. A target load limit unit 39 is provided which limits the target load so as not to exceed a second value (e.g. 0.18 Hz) smaller than the value (e.g. 0.2 Hz).

  In the present embodiment, since the power amount limiting unit 28 is provided to limit the amount of power that can be generated, it is possible to allow room for the power that can be used in the ship. As a result, it is possible to reduce the possibility that the assist operation generates power shortage in the ship. The possible power amount computing unit 27 is realized by step ST14 of the flowchart shown in FIG. The power amount limiting unit 28 is realized by step ST15 of the flowchart shown in FIG. The surplus power calculating unit 31 is realized by step ST6 of the flowchart shown in FIG. The surplus power value determination unit 33 is realized by step ST7 of the flowchart shown in FIG. The target load determination unit 35 is realized by step ST8 of the flowchart shown in FIG. The target load limit unit 39 is realized by steps ST10 and ST11 of the flowchart shown in FIG.

  The target load determination unit 35 determines the target load by calculation when the surplus power value determined by the surplus power value determination unit 33 (step ST7) has a positive value “+” (step ST8), and the surplus power value is negative. When the target load has a value of “−”, the target load previously determined is reduced in a range where the hunting phenomenon does not occur (step ST9). If the surplus power value is 0, the process returns to step ST6. In addition, even if the calculated surplus power has a negative value, the surplus power may have a positive value in a short time. Therefore, even when the surplus power value has a negative value, it is sufficient to reduce the assist load by reducing the target load. However, if the reduction amount of the target load is increased too much, a hunting phenomenon occurs in which the inboard frequency becomes unstable. Therefore, it is preferable to reduce the target load in the range where the hunting phenomenon does not occur. In the present embodiment, when the surplus power value has a negative value, the target load determination unit 35 determines the reduction amount of the target load so that the surplus power value having a negative value becomes 0 or a value close to 0. To do at predetermined time intervals (5 seconds). If the reduction amount of the target load is determined at predetermined time intervals, the occurrence of the hunting phenomenon can be suppressed. In the flowchart of FIG. 2, performing the above determination is described as “surplus 0 0”.

  Further, in the present embodiment, the target load determination unit 35 includes the allowable load setting unit 37 that sets the allowable load of the shaft generator / motor 13. If the allowable load of the shaft generator / motor 13 can be set by the allowable load setting unit 37, the shaft power generation can be performed by setting the allowable load of the shaft generator / motor 13 in consideration of the operation situation of the ship. The assist operation can be performed without exerting an excessive force on the machine / motor 13.

  As in the present embodiment, when the target load limit unit 39 (steps ST10 and ST11) is provided, the target load increases more than the second value (within 0.18 Hz of step ST10) set by the target load limit unit 39. It is possible to prevent the frequency fluctuation range in the electrical network 9 from becoming large. Therefore, the positive assist operation performed using the shaft generator / motor 13 can be effectively used (step ST12). Further, if the frequency fluctuation range in the electric network 9 becomes equal to or more than the first value due to reasons other than the assist operation (for example, determination of 0.2 Hz decrease in step ST2 of FIG. 2), the frequency fluctuation suppression unit 19 suppresses the assist operation. To suppress frequency fluctuations. In step ST13, it is determined whether or not there is an input of a termination command (or switching command) for the assist operation, and if the termination command (or switching command) is not input, the process returns to the start point of control. If it is detected in step ST13 that the assist operation end command (or switching command) has been input, the assist operation is ended.

  The first value which is the limit value of the frequency fluctuation range in the electric network 9 is a value of 0.2 Hz or more and 0.3 Hz or less, and the second value and the first value set by the target load limit unit 39 Preferably, the second value is determined such that the difference between Within this numerical range, the assist operation can be performed without increasing the fluctuation of the power frequency in the ship.

  Furthermore, the ship propulsion assist system 3 further includes an instantaneous power increase response unit 34 that suppresses the assist operation by the ship propulsion assist system 3 when the instantaneous electric energy in the electric network 9 in the ship becomes a predetermined value or more. There is. The instantaneous power increase handling unit 34 suppresses the assist operation by reducing the target load so as to compensate for the increase in the instantaneous power when the instantaneous power becomes equal to or greater than a predetermined value. With regard to the increase of the instantaneous power amount, even if hunting occurs, it is preferable to actively distribute power to the inside of the ship even if the target load is reduced and the assist operation is sacrificed. By providing the instantaneous power increase handling unit 34, surplus power can be used for rapid increase of instantaneous power, so that the power demand on the ship can be met. Specifically, the instantaneous power increase handling unit 34 instructs the control signal generation unit 23 of the drive control device 21 that controls the drive of the shaft generator / motor 13 to reduce the target load. The instantaneous power increase handling unit 34 is realized by steps ST21 and ST22 of the flowchart shown in FIG. If it is detected in step ST21 that the instantaneous electric energy has increased by 100 kW, then in step ST22, an instruction to reduce the target load is issued. In the present embodiment, the amount of reduction is not particularly limited. Of course, a certain limit may be added to the reduction amount. The “100 kW increase” is determined from the relationship between the output of the generator and the load, and is not limited to “100 kW” in implementing the present invention.

  In the present embodiment, the determination of the frequency variation in the frequency variation range determination unit 17 and the determination by the surplus power value determination unit 33 are performed at the same timing cycle. Therefore, it is possible to prevent the target load from being reduced redundantly. Further, the calculation of the possible power amount calculation unit 27 and the measurement by the inboard power measurement unit 29 are always performed.

  Steps ST16 to ST19 in FIG. 2 are control steps of the generator 7. Since this control step is known, the description is omitted here. In step ST16, it is determined whether the amount of power that can be generated is increased or decreased. If the amount of power that can be generated is "increase", the target load of the generator 7 is increased (step ST18), and if the amount of power that can be generated is "decrease", the target load of the generator 7 is reduced (step ST17). In step ST19, the operation of the generator (STG) 7 is controlled based on the result of step ST17 or step ST18, and the process returns to step ST14. In step ST16, if the amount of power that can be generated is "zero", the process returns to step ST14 to maintain the current state.

[Switching signal generation system]
When there is no surplus power, the ship propulsion assist system 3 performs a power supply operation of supplying the generated electrical energy to the electrical network by driving the shaft generator / motor 13 as the shaft generator by the propeller shaft 11, and the switching signal is input. Then, it has a switching function of switching the shaft generator / motor 13 from the shaft generator to the motor or from the motor to the shaft generator. The configuration of a system that specifically implements this switching function is arbitrary. Before the present embodiment is developed, when switching from the shaft generator to the motor or from the motor to the shaft generator as a control signal (a governor signal) for the shaft generator and motor as shown in FIG. 4B. There has been a switching signal generation system which gives a control signal such that the pulse width is shortened gradually or in stages, and generates a switching signal when a predetermined cumulative time reaches a predetermined switching preparation time. However, in such an existing system, it takes a considerably long time for the predetermined cumulative time to reach the predetermined switch preparation time, which causes a problem that quick switching can not be performed. In addition, when the switching signal is not output from the switching signal output unit due to disconnection or failure, the switching operation can not be performed. Therefore, in the present embodiment, even when the existing switching signal generation system is adopted, the switching signal can be generated quickly, and when the switching signal is not output due to disconnection, failure or the like, the shaft generator The motor switching operation can be stopped.

  FIG. 3 is a flowchart showing an algorithm of software used when executing the switching signal generation system having the switching function using a computer. FIG. 4A is a diagram used to explain the relationship between the output power measured by the power measurement unit 41 or the deviation between 0 kW and the input power, and FIG. 4B shows an example of a conventional control signal (a governor signal). (C) is a diagram showing an example of a control signal (a governor signal) in a comparative example when performing the switching function, and (D) is a diagram when performing the switching function in the present embodiment. It is a figure which shows the example of the control signal (governor signal) output from the control signal generation part of these. In order to realize the switching function, the vessel propulsion assist system 3 according to the present embodiment measures the output power output from the shaft generator / motor 13 and the input power input to the shaft generator / motor 13. A switching signal generation unit 43 for outputting a switching signal for switching the shaft generator / motor 13 from the shaft generator to the motor or from the motor to the shaft generator based on the output of the power measuring unit 41 and the control signal Is equipped. The switching signal generation unit 43 includes an input time accumulation unit 45 and a switching signal output unit 47. When the shaft generator / motor 13 functions as a motor, the power measuring unit 41 measures the input power supplied to the shaft generator / motor 13 through the input / output line IOL using a known power measurement technique, When the shaft generator / motor 13 functions as a generator, the output power supplied to the onboard electrical network 9 through the input / output line IOL is measured using a known power measurement technique.

  After the output time or input power of the shaft generator / motor 13 measured by the power measurement unit 41 becomes smaller than the predetermined switching preparation power (step ST22), the input time accumulation unit 45 of the switching signal generation unit 43 When the output power or input power of the generator / motor 13 is in the 0 kW state (step ST25), the input time of the control signal (the governor signal) is accumulated and stored as the accumulated time (step ST26). In addition, in step ST22 of FIG. 3, although it should originally be written as “SGM output <5% or less or SGM input <5% or less”, for convenience, it is described as SGM output <5% or less. In step ST25, although "SGM output = 0% or SGM input = 0%" should be described, for convenience, it is described as SGM output = 0%.

  Then, switching signal output unit 47 outputs a switching signal (step ST28) when the cumulative time has passed a predetermined switching preparation time (in this embodiment, cumulative 3 seconds) (step ST28), and the switching operation is ended. To do (step ST29). The switching preparation time is based on a rule of thumb, and if the switching preparation time is too short, a malfunction of the switching operation tends to occur, and if the switching preparation time is long, a switching delay occurs.

  In the present embodiment, as shown in FIG. 4 (A), the input time accumulation unit 45 predetermines the output power or input power (output power or input power of the shaft generator / motor) measured by the power measurement unit 41 in advance. When it becomes smaller than the determined switching preparation power (5%) (step ST22), a continuous signal output command is output to the control signal generator 23 (step ST23). When receiving the continuous signal output command, the control signal generation unit 23 outputs the continuous signal to the drive circuit 25 as shown in FIG. 4 (D). After the control signal generation unit 23 outputs the control signal (the governor signal) as a continuous signal to the drive circuit 25 for a predetermined time (8 consecutive seconds) longer than the switching preparation time (3 seconds cumulatively) (steps ST23 and ST24) After confirming the end of the switching operation, the control signal generation unit 23 stops the output of the control signal (the governor signal) (step ST30). Thereafter, control of the shaft generator / motor 13 returns to normal control (step ST31).

  In this case, when performing the switching operation, continuous control signals are input to the input time accumulation unit 45, so accumulation is performed in a shorter time than when a control signal having a shorter pulse width is input as in the prior art. The time comes to reach the switching preparation time. Therefore, according to the present embodiment, control is performed such that the pulse width is gradually or stepwise shortened when switching from the shaft generator to the motor or from the motor to the shaft generator using the existing switching signal generation system. Even in the case of giving a signal, the accumulation time is continuously accumulated by setting the control signal as a continuous signal after the output power or input power of the shaft generator / motor 13 becomes smaller than the predetermined switching preparation power. It can be done. Therefore, the switching signal can be generated quickly. Even when disconnection or failure occurs in the switching signal generation unit and the switching signal is not output, the control signal as a continuous signal generated by the control signal generation unit 23 stops at a predetermined time. As a result, even if the switching signal is not output, the output of the control signal can be stopped and the switching operation of the shaft generator / motor 13 can be stopped.

  The switching signal generation unit 43 and the control signal generation unit 23 execute the processes of steps ST23 and ST24 and the processes of steps ST25 to ST29 at the same time. FIG. 4D shows control signals generated in steps ST23 and ST24. In the process of steps ST25 to ST29, since a continuous signal is output as a control signal, “3 seconds” accumulation is completed within a time shorter than a predetermined time (8 seconds continuously), and a switching signal is output. Be done. However, even if disconnection or failure occurs in switching signal generation unit 43 and the switching signal is not output (the accumulation is not completed), the processes of steps ST23 and ST24 are performed in parallel, so it is longer than the switching preparation time. When the control signal continues to be output for a predetermined time (8 seconds), the control signal generator 23 stops the output of the control signal. As a result, when the switching signal is not output, the output of the control signal can be stopped to stop the switching operation of the shaft generator / motor. As a result, according to the present invention, it is possible to prevent the occurrence of a situation where the switching signal is not output and the operation of the shaft generator / motor can not be switched. Incidentally, as shown in FIG. 4C, when the control signal generator 23 continues to output a continuous signal, the output continues to abnormally rise as shown by the curve “C” in FIG. 4A.

  In the above switching operation, as a condition for mode switching, after the axis generator / motor 13 recognizes 0 kW, the control signal (the governor signal) must be accumulated for 3 seconds or more and output. However, when the control signal is interrupted, smooth switching may not be performed. However, according to the present embodiment, at the time of switching of the shaft generator / motor 13, the control signal (the governor signal) is continuously output for 8 seconds if it falls within the rated value of 5% of the motor or generator. It was decided to stop the control signal (the governor signal) at a point in time. This made it possible to switch smoothly.

  In the present embodiment, steps ST25 to ST29 are realized by using a switching system "SGH105BS-20" sold by Taiyo Electric Co., Ltd. The switching preparation power is preferably a value between 4% and 6% of the rated power. If the switching preparation power is smaller than 4%, it takes a long time, and if it is larger than 6%, the load fluctuation becomes large.

[Operation efficiency display]
In the motor, in the process of energy conversion, some energy is always lost. Therefore, the operating efficiency of the main engine excitation (SM) that fluctuates depending on the main engine rotational speed and the power load is important information that affects the fuel efficiency of the ship, and has to be constantly calculated. However, in the main switchboard (not shown), although the amount of power input to the shaft generator / motor 13 can be grasped, the amount of work to be applied to the main machine is not actually known, and the efficiency value can not be calculated. Therefore, even the ship propulsion assist system equipped with the present exhaust heat recovery system does not present information on the driving efficiency of the ship propulsion assist system to the driver of the ship. Under the present circumstances, it is a fact that the driver of the ship selects the assist mode without knowing whether the ship propulsion assist system is operated efficiently. Therefore, there is a situation where the driver does not have information for selecting the operation mode and can not select the appropriate operation mode even if the ship propulsion assist system is to have a plurality of operation modes.

  Therefore, in the present embodiment, using the test data of the shaft generator / motor 13 on land, the efficiency is calculated from the main machine rotational speed and the power load factor, and the workload of the shaft generator / motor 13 is calculated. I made it. This makes it possible to calculate and display efficiency instantly. Specifically, in the present embodiment, in order to display the efficiency of the shaft generator / motor 13 on the display screen of the monitor of the main switchboard, the output power generated by the shaft generator / motor 13 and the shaft generator / motor 13 And a rotation number measurement unit 49, an efficiency calculation unit 51, and a correlation display unit 53. FIG. 5 shows an example of an algorithm of software used when displaying the efficiency of the shaft generator / motor on the display screen of the monitor using these components.

  The rotation speed measurement unit 49 measures the rotation speed of the propeller shaft 11 when the shaft generator / motor 13 is rotating (step ST41). The efficiency calculating unit 51 calculates the rotational speed detected by the rotational speed measuring unit 49, the output power or input power measured by the power measuring unit 41 (step ST42), the rotational speed of the propeller shaft 11 and the shaft generator The efficiency of the shaft generator / motor is calculated based on the data indicating the relationship with the efficiency of the motor 13 (step ST43). The data indicating the relationship between the propeller shaft 11 and the efficiency of the shaft generator / motor 13 obtained in advance can be shop data indicated by the manufacturer of the shaft generator / motor 13 in the specification. The relationship display unit 53 can visually recognize the relationship among the number of rotations measured by the rotation number measurement unit 49, the efficiency calculated by the efficiency calculation unit 51, and the output power or input power measured by the power measurement unit 41. It displays on the monitor which is not illustrated (step ST44).

  If the efficiency of the shaft generator / motor 13 is displayed for visual recognition, a driver who does not like automatic driving can freely select a preferred operation mode in consideration of the efficiency and other situations.

  FIG. 6A shows an example of the display of the number of rotations, the output power or the input power, and the efficiency displayed on the display screen of the monitor by the correlation display unit 53. In the display of FIG. 6 (A), the relationship between each other is displayed on a monitor by a three-axis graph displaying the number of rotations on the X axis, output power or input power on the Y axis, and efficiency on the Z axis. Further, in the display of FIG. 6A, other measured values or calculated values are displayed together with the 3-axis graph. The intersection of the values of the three axes displayed by the interrelation display unit 53 relates to the current torque of the main machine driving the propeller shaft 11. In addition, if the position of this intersection is confirmed, the following can be performed. Specifically, as shown in FIG. 6 (B), when the preferred driving zone ZN set by the driver is displayed in advance on the display screen, the intersection points (R1, R2) are selected from the preferred driving zone ZN when performing the assist driving. If it is not, it is sufficient to take measures such as stopping the assist. In addition, when these three values are displayed, although the rotation speed of the main unit increases and the rotation speed of the shaft generator / motor 13 also increases, the cause is that the input power is limited when the efficiency is not improved. It can be seen at first glance that the input power is insufficient because control is being performed. In such a case, it is understood that the control may be performed in the operation mode in which the restriction on the input power is released. Also, when the sea is rough and the rotation speed of the main unit is high, the load fluctuation of the main unit becomes severe, and a phenomenon that the intersection (R1, R2) of the three-value display shakes appears. In such a state, even if the efficiency is high, a step-out or tripping phenomenon may temporarily occur in the shaft generator / motor 13 and an overcurrent may flow. Therefore, in such a situation, it is also possible to select the operation mode for stopping the assist operation in consideration of safety.

[0 kW hold at stop and selection of operation mode]
In the ship propulsion system provided with the conventional exhaust heat recovery system, before starting operation of the ship propulsion assist system, the shaft generator / motor 13 is separated from the drive control system and the ship propulsion assist system is operated. In general, the shaft generator / motor 13 is connected to a drive control system. However, when the ship propulsion assist system is operated, if the assist operation is to be started, the shaft generator / motor may perform the power supply operation.

  Therefore, in the ship propulsion assist system 3 according to the present embodiment, the output of the shaft generator / motor 13 is set to 0 kW when the assist operation or the power supply operation is not performed in the state where the generator (STG) 7 is generating power. It was decided to control the shaft generator / motor 13 so that

  Here, “control the shaft generator / motor so that the output is 0 kW state” means to control the current flowing in the winding of the shaft generator / motor 13 as close to 0 as possible. It means that the power is controlled to be in the 0 kW state (for example, in the range of 0 kW ± 2% of the rated power). In the 0 kW state, the output of the shaft generator / motor 13 is maintained close to 0 even if the rotor of the shaft generator / motor 13 is rotating. Therefore, according to the present invention, when the assist operation is started from the inactive state, the current flowing to the winding is controlled and limited, so that the situation where the power supply operation is started from the non-controlled state occurs. It can prevent. Therefore, in the present embodiment, when the assist operation is started from the state where the vessel propulsion assist system 3 is at rest, the assist operation can be reliably started. As shown in FIG. 6B, in the 0 kW state, the intersection of the three-value display is as shown by R3.

  This control is performed in the drive control device 21 based on the selection of the operation mode via the mode selection unit 55 in FIG. FIG. 7 shows an algorithm of software used to execute this control using a computer.

  Specifically, the mode selection unit 55 operates in a first operation mode in which the shaft generator / motor 13 is operated as an axis generator or motor, and in a second operation mode in which the shaft generator / motor 13 is operated as a motor. Is selectable. According to this selection, the boat propulsion assist system selects the first operation mode or the second operation mode before the first operation mode or the second operation mode is selected in the control signal generation unit 23. The axis generator / motor 13 is controlled so that the output of the axis generator / motor 13 becomes 0 kW until it is executed (steps ST51 and ST52). Specifically, the 0 kW state can be created by limiting the current flowing in the winding of the shaft generator / motor 13 as close to 0 as possible. In this way, the assist operation can be performed in the selected mode. As shown in FIG. 4A, the drive control device 21 sets a predetermined dead zone within ± 2% of the rating centering around 0 kW so that the output of the shaft generator / motor 13 becomes 0 kW. It is preferable to limit the current to Providing such a dead zone can prevent the control from becoming unstable.

  In the flowchart of FIG. 7, immediately after the parallel operation of the generator 7 and the shaft generator / motor 13, either the SM MODE as the second operation mode or the SM / SG MODE as the first operation mode is selected as the mode selection unit The selection is made manually at step 55 (step ST53). While waiting for the selection, the generator 7 bears all inboard loads, and the shaft generator and motor 13 maintains 0 kW, in order not to allow the shaft generator and motor 13 to function. FIG. 8 shows that the generator 7 bears all inboard loads while the generator 7 and the shaft generator / motor 13 are in parallel operation, and the shaft generator / motor 13 always maintains 0 kW.

  If SM / SG MODE is selected, it is judged whether or not there is surplus power (step ST57). If there is surplus power, SM operation (motor operation) is executed, and if there is no surplus power, SG operation (generator operation) Are executed (steps ST59 and ST61). That is, in the SM / SG MODE, in addition to the function of the SM MODE, the shaft generator / motor 13 is also used as a generator for the purpose of reducing the number of times of automatic backup of the diesel generator mounted on the ship. If surplus power is lost in the generator 7 and the internal load can not be absorbed only by the generator 7, the shaft generator / motor 13 is automatically switched from the motor to the generator to generate power. In addition, even if power generation is performed as a generator, if the power in the ship can not be taken over, the diesel generator mounted on the ship is automatically backed up when the surplus power below a certain level, and the shaft generator / motor 13 is automatic. Cut off. During normal voyage of the ship, this basic mode is selected. In FIG. 9, while the generator 7 and the shaft generator / motor 13 are in parallel operation, the shaft generator / motor 13 performs the main machine energization for the surplus power of the generator 7, and if the power of the generator 7 is insufficient It shows switching to cover the inboard load for the shortfall.

  When SM MODE is selected, it is judged whether or not there is surplus power (step ST65), and SM operation (motor operation) is executed only when there is surplus power (step ST67). In addition, in step ST65, if there is no surplus power in the generator 7, the axis generator / motor 13 maintains 0 kW operation. This mode is selected when the shaft generator / motor 13 is not desired to be used as a generator. In FIG. 10, while the generator 7 and the shaft generator / motor 13 are in parallel operation, the generator 7 bears the inboard load and the motor load of the shaft generator / motor 13 at maximum, and the shaft generator / motor 13 is a generator 7 Shows how to boost the main machine with the surplus power of

  When the OFF MODE (the mode in which the shaft generator / motor 13 is not used) is manually selected by the mode selection unit 55 (step ST69), the process returns to step ST51, and 0 kW retention is started again.

  The main control portion of the above embodiment can be realized using one computer (processor) and one storage device, but it may be realized by combining a plurality of computers (processors) and a plurality of storage devices. Of course it is good.

  According to the present invention, using an existing switching signal generation system, a control signal is provided such that the pulse width is reduced gradually or stepwise when switching from the auxiliary generator to the motor or from the motor to the shaft generator. Even in this case, the accumulation time can be continuously accumulated by using the control signal as a continuous signal after the output power or input power of the shaft generator / motor becomes smaller than the predetermined switching preparation power. Therefore, according to the present invention, the switching signal can be generated quickly. Even when disconnection or failure occurs in the switching signal generation unit and the switching signal is not output, the control signal as a continuous signal generated by the control signal generation unit stops at a predetermined time. As a result, even if the switching signal is not output, the control signal can be stopped to stop the switching operation of the shaft generator / motor.

DESCRIPTION OF SYMBOLS 1 Waste heat recovery system 3 Ship propulsion assist system 5 Turbine 7 Generator 9 Electric network 11 Propeller shaft 13 Axis generator and motor 15 Frequency measurement unit 17 Frequency fluctuation range judgment unit 19 Frequency fluctuation suppression unit 21 Drive control device 23 Control signal generation Unit 25 Drive circuit 27 Possible power amount computing unit 28 Power amount limiting unit 29 Inboard power measuring unit 31 Excess power computing unit 33 Excess power value judging unit 34 Instantaneous power increase handling unit 35 Target load determination unit 37 Allowable load setting unit 39 Target Load limit unit 41 Power measurement unit 43 Switching signal generation unit 45 Input time accumulation unit 47 Switching signal output unit 49 Rotation speed measurement unit 51 Efficiency calculation unit 53 Relationship display unit 55 Mode selection unit

Claims (2)

An exhaust heat recovery system comprising: a turbine and a generator for supplying electric energy using waste heat as an energy source;
An axial generator / motor connected to a propeller shaft is provided, and surplus electric power generated by the generator is supplied to the electric network and surplus electric power is supplied to the axial electric generator / motor to be supplied with the surplus electric power. By converting the propeller shaft into mechanical energy for driving the propeller shaft, an assist operation is performed to assist the propulsion of the ship by the propeller shaft, and when the surplus electric power is lost, the propeller and the motor are used as the shaft generator. A power supply operation is performed to supply electric energy generated by driving with a shaft to the electric network, and when a switching signal is input, the shaft generator / motor from the shaft generator to the motor or from the motor to the shaft generator A ship propulsion assist system having a switching function to switch;
A control signal generation unit which gives a control signal for decreasing the pulse width gradually or in stages when switching from the shaft generator to the motor or from the motor to the shaft generator to the drive control device for the shaft generator / motor; ,
A power measurement unit that measures output power output from the shaft generator / motor and input power input to the shaft generator / motor;
A switching signal generation unit for outputting the switching signal to switch the shaft generator / motor from the shaft generator to the motor or from the motor to the shaft generator based on the output of the power measuring unit and the control signal Equipped
The control signal is input when the output power or the input power becomes 0 kW after the switching signal generation unit measures the output power measured by the power measuring unit or the input power smaller than a predetermined switching preparation power. An input time accumulation unit that accumulates time and stores it as accumulated time;
The vessel propulsion system includes an exhaust heat recovery system including: a switching signal output unit that outputs the switching signal when the cumulative time has passed a predetermined switching preparation time,
When the output power measured by the power measurement unit or the input power becomes smaller than the predetermined switching preparation power, the control signal generation unit sets the control signal as a continuous signal and is longer than the switching preparation time. A vessel propulsion system comprising an exhaust heat recovery system characterized by stopping output of the control signal after time output.   The ship propulsion system provided with the exhaust heat recovery system according to claim 1, wherein the switching preparation power is a value of 4% to 6% of the rated power.

Images