Power unit system control unit

Abstract

To reduce rotational frequency of a gas turbine for a short time when lowering output power of the gas turbine.SOLUTION: When output power of a gas turbine 16 is lowered, if relation between rotational frequency and target output power of the gas turbine 16 satisfies a predetermined condition, a control device 40 for a power unit system 10 lowers the output power of the gas turbine 16 to the target output power and then, decelerates the gas turbine 16 to target rotational frequency. If the relation between the rotational frequency and the target output power of the gas turbine 16 satisfies a predetermined condition, the control device decelerates the gas turbine 16 to the target rotational frequency and then, lowers the output power of the gas turbine to the target output power.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control device for a power unit system.

Background Art

[0002] Patent Document 1 below discloses a control device for a gas turbine generator. In the gas turbine generator, a generator is driven by a gas turbine. Thereby, the generator generates electricity. When increasing the amount of power generated by the generator, the control device reduces the load on the generator by causing the battery to supply power to the load. While the load on the generator is reduced, the rotational speed of the gas turbine is increased. Thereafter, the control device increases the output power of the gas turbine to increase the amount of power generated by the generator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology disclosed in Patent Document 1 above, when increasing the output power of the gas turbine, the rotational speed of the gas turbine can be increased in a short time. However, there is room for improvement in reducing the rotational speed of the gas turbine in a short time when reducing the output power of the gas turbine.

[0005] An object of the present invention is to solve the above-described problems.

Means for Solving the Problems

[0006] An aspect of the present invention is a control device for a power unit system comprising a gas turbine having a compressor and a turbine rotating integrally with the compressor, a generator driven by the gas turbine, and a battery for storing the electricity generated by the generator, wherein the control device comprises: a requested power generation setting unit for setting the requested power generation to the generator; a fuel injection amount setting unit for controlling the amount of fuel injected into the combustion chamber of the gas turbine; a target rotational speed setting unit for setting the target rotational speed of the gas turbine with respect to the target output power of the gas turbine; and a condition determination unit for determining whether the relationship between the rotational speed of the gas turbine and the target output power satisfies predetermined conditions, wherein when the output power of the gas turbine is to be reduced, and the relationship between the rotational speed of the gas turbine and the power satisfies the predetermined conditions, the requested power generation setting unit reduces the requested power generation, and the fuel injection In cases where the injection amount setting unit reduces the injection amount to lower the output power of the gas turbine to the target output power, and then the requested power generation setting unit maintains the requested power generation, and the fuel injection amount setting unit reduces the injection amount to decelerate the rotational speed of the gas turbine to the target rotational speed and lower the output power of the gas turbine, if the relationship between the rotational speed of the gas turbine and the target output power does not satisfy the predetermined conditions, the requested power generation setting unit maintains the requested power generation, and the fuel injection amount setting unit reduces the injection amount to decelerate the rotational speed of the gas turbine to the target rotational speed, and then the requested power generation setting unit reduces the requested power generation, and the fuel injection amount setting unit reduces the injection amount to lower the output power of the gas turbine to the target output power. [Effects of the Invention]

[0007] The present invention makes it possible to reduce the rotational speed of a gas turbine in a short amount of time when reducing the output power of the gas turbine. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing the configuration of the power unit system, drive unit, and control unit. [Figure 2] Figure 2 is a block diagram showing the configuration of the hybrid controller. [Figure 3] Figure 3 is a graph showing the operating range of the gas turbine. [Figure 4] Figures 4A and 4B are diagrams illustrating the concept of first output power reduction control. [Figure 5] Figure 5 is a graph showing the shift in the operating point of the gas turbine. [Figure 6] Figures 6A and 6B are diagrams illustrating the concept of second output power reduction control. [Figure 7] Figure 7 is a graph showing the shift in the operating point of the gas turbine. [Figure 8] Figure 8 is a graph showing the shift in the operating point of the gas turbine. [Figure 9] Figure 9 is a table comparing the time required to reduce the output power of a gas turbine to the target output power. [Figure 10] Figure 10 is a flowchart showing the output power reduction control process. [Modes for carrying out the invention]

[0009] [First Embodiment] [Overall structure] Figure 1 is a schematic diagram showing the configuration of the power unit system 10, the drive unit 12, and the control unit 14.

[0010] The power unit system 10 includes a gas turbine 16, a generator 18, a converter 20, and a battery 22. The gas turbine 16 generates rotational energy, which drives the generator 18. The generator 18 generates electricity when driven by the gas turbine 16. The converter 20 converts the alternating current power generated by the generator 18 into direct current power and outputs it. The battery 22 stores a portion of the electricity generated by the generator 18.

[0011] The gas turbine 16 includes a compressor 24, a combustion chamber 26, and a turbine 28. Air drawn in from the intake port 30 is compressed in the compressor 24. The compressed, high-pressure air is sent to the combustion chamber 26. In the combustion chamber 26, fuel is injected into the high-pressure air and the fuel is burned. This generates high-temperature, high-pressure gas in the combustion chamber 26. This gas rotates the turbine 28. The energy of the high-temperature, high-pressure gas is converted into rotational energy by the turbine 28 and extracted by the output shaft 32. A portion of this rotational energy is also used to rotate the compressor 24.

[0012] The drive unit 12 includes an inverter 34 and an electric motor 36. The inverter 34 converts the DC power supplied from the converter 20 or battery 22 into AC power and outputs it to the electric motor 36. The electric motor 36 is driven by the power supplied from the inverter 34.

[0013] The control unit 14 includes an SOC acquisition unit 38, a hybrid controller 40, and an electric motor controller 42. The SOC acquisition unit 38 acquires the State of Charge (SOC) of the battery 22. The hybrid controller 40 controls the gas turbine 16 and the converter 20 based on the requested power input from the electric motor controller 42 and the SOC of the battery 22 input from the SOC acquisition unit 38. This controls the output power and rotational speed of the gas turbine 16. The hybrid controller 40 corresponds to the control device of the present invention. The electric motor controller 42 controls the inverter 34 based on the generated power of the generator 18 input from the hybrid controller 40 and the SOC of the battery 22 input from the SOC acquisition unit 38 via the hybrid controller 40. This controls the output power and rotational speed of the electric motor 36.

[0014] [Hybrid Controller Configuration] Figure 2 is a block diagram showing the configuration of the hybrid controller 40.

[0015] The hybrid controller 40 has an arithmetic unit 44 and a storage unit 45. The arithmetic unit 44 is a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), for example. The arithmetic unit 44 has a fuel injection amount setting unit 46, a required power generation power setting unit 47, a target rotation speed setting unit 48, and a condition determination unit 49. The fuel injection amount setting unit 46, the required power generation power setting unit 47, the target rotation speed setting unit 48, and the condition determination unit 49 are realized by a program stored in the storage unit 45 being executed by the arithmetic unit 44. At least a part of the fuel injection amount setting unit 46, the required power generation power setting unit 47, the target rotation speed setting unit 48, and the condition determination unit 49 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). At least a part of the fuel injection amount setting unit 46, the required power generation power setting unit 47, the target rotation speed setting unit 48, and the condition determination unit 49 may be realized by an electronic circuit including discrete devices.

[0016] The storage unit 45 is composed of a volatile memory (not shown) and a non-volatile memory (not shown) which are computer-readable storage media. The volatile memory is, for example, a RAM (Random Access Memory) or the like. The non-volatile memory is, for example, a ROM (Read Only Memory), a flash memory, or the like. Data and the like are stored in the volatile memory, for example. Programs, tables, maps, and the like are stored in the non-volatile memory, for example. At least a part of the storage unit 45 may be provided in the above-described processor, integrated circuit, or the like.

[0017] The fuel injection amount setting unit 46 sets the fuel injection amount into the combustion chamber 26 of the gas turbine 16. Based on the injection amount set in the fuel injection amount setting unit 46, fuel is injected into the combustion chamber 26 of the gas turbine 16.

[0018] The power generation request setting unit 47 sets the power generation request for the generator 18. The converter 20 adjusts the power generation load of the generator 18 according to the power generation request. The rotational speed of the gas turbine 16 is controlled by adjusting the amount of fuel injected into the combustion chamber 26 of the gas turbine 16 and the power generation load of the generator 18. For example, if the amount of fuel injected decreases while the power generation load is maintained, the rotational speed of the gas turbine 16 will decrease.

[0019] The target rotational speed setting unit 48 sets the target rotational speed of the gas turbine 16. The target rotational speed is set according to the target output power. The relationship between the target output power and the target rotational speed will be described in detail later.

[0020] The condition determination unit 49 determines whether the relationship between the rotational speed of the gas turbine 16 and the target output power satisfies predetermined conditions. These predetermined conditions will be described in detail later.

[0021] [Gas turbine operating range] Figure 3 is a graph showing the operating range of the gas turbine 16. The horizontal axis of the graph in Figure 3 represents the rotational speed of the gas turbine 16. The vertical axis of the graph in Figure 3 represents the output power of the gas turbine 16.

[0022] The misfire line shown in Figure 3 indicates the minimum output power of the gas turbine 16 relative to its rotational speed. If the operating point, determined by the rotational speed and output power of the gas turbine 16, is located below the misfire line, a misfire may occur in the combustion chamber 26, potentially causing the gas turbine 16 to stop. The maximum output power line shown in Figure 3 indicates the maximum output power of the gas turbine 16 corresponding to its rotational speed. If the operating point of the gas turbine 16 is located above the maximum output power line, the compressor 24 may stall, potentially causing the gas turbine 16 to stop. Alternatively, if the operating point of the gas turbine 16 is located above the maximum output power line, the temperature of the gas supplied to the turbine 28 may become too high. Therefore, the operating point of the gas turbine 16 must be located within the movable range between the misfire line and the maximum output power line.

[0023] The SFC (Specific Fuel Consumption) best line shown in Figure 3 represents the relationship between the output power and rotational speed of the gas turbine 16 that results in the best fuel consumption rate. For example, to maintain the output power of the gas turbine 16 at P3 [W], the greater the rotational speed of the turbine 28 than N2, the greater the amount of fuel that needs to be injected into the combustion chamber 26. To maintain the output power of the gas turbine 16 at P3 [W], the less the rotational speed of the turbine 28 than N2, the greater the amount of fuel that needs to be injected into the combustion chamber 26. Based on the SFC best line, the target rotational speed for the target output power is set.

[0024] [Gas turbine power reduction control] The target output power of the gas turbine 16 is determined according to the required output power of the electric motor 36. That is, if the required output power of the electric motor 36 decreases, the target output power also decreases. When the target output power decreases, the hybrid controller 40 performs output power reduction control to reduce the output power of the gas turbine 16.

[0025] If the relationship between the rotational speed of the gas turbine 16 and the target output power satisfies predetermined conditions, the hybrid controller 40 performs first output power reduction control. On the other hand, if the relationship between the rotational speed of the gas turbine 16 and the target rotational speed does not satisfy predetermined conditions, the hybrid controller 40 performs second output power reduction control.

[0026] The predetermined condition is that the virtual operating point is located above the misfire line. The virtual operating point is determined by the rotational speed of the gas turbine 16 and the target output power at the start of the power reduction control.

[0027] Even if the relationship between the rotational speed of the gas turbine 16 and the target output power satisfies the aforementioned predetermined conditions, the hybrid controller 40 may perform a second output power reduction control if the rotational speed of the gas turbine 16 at the start of output power reduction control is N3 [rpm] or less. When the rotational speed of the gas turbine 16 is N3 [rpm] or less, the operating point of the gas turbine 16 at the start of output power reduction control is located in the narrow movable region shown in Figure 3.

[0028] In the first power reduction control, the hybrid controller 40 reduces the output power of the gas turbine 16 to a target output power, and then reduces the rotational speed of the gas turbine 16 to a target rotational speed. On the other hand, in the second power reduction control, the hybrid controller 40 reduces the rotational speed of the gas turbine 16 to a target rotational speed, and then reduces the output power of the gas turbine 16 to a target output power.

[0029] [Regarding the first output power reduction control] The first output power reduction control will be described below. Figures 4A and 4B are diagrams illustrating the concept of the first output power reduction control. Figure 4A is a graph showing the time variation of the target output power of the gas turbine 16, the output power (actual output power) of the gas turbine 16, and the required power generation of the generator 18. Figure 4B is a graph showing the time variation of the target rotational speed of the gas turbine 16 and the rotational speed (actual rotational speed) of the gas turbine 16. Figures 4A and 4B conceptually illustrate the time variation of each element.

[0030] At time t1, the target output power decreases. Consequently, the target rotational speed decreases. After time t1, the requested power generation setting unit 47 gradually reduces the requested power generation. At the same time, the fuel injection amount setting unit 46 gradually reduces the fuel injection amount. As a result, the actual output power gradually decreases. In this case, due to the inertia of the rotational elements of the gas turbine 16, the rotational speed of the gas turbine 16 hardly changes.

[0031] At time t2, the actual output power decreases to the target output power. From time t2 onward, the requested power generation setting unit 47 maintains the requested power generation power. At this time, the fuel injection amount setting unit 46 further reduces the fuel injection amount. As a result, the rotational speed of the gas turbine 16 decreases.

[0032] At time t3, the actual rotational speed decreases to the target rotational speed. At time t3, the requested power generation setting unit 47 maintains the requested power generation, while the fuel injection amount setting unit 46 maintains the fuel injection amount. As a result, the hybrid controller 40 can set the output power of the gas turbine 16 to the target output power and the rotational speed of the gas turbine 16 to the target rotational speed.

[0033] The first power reduction control will be explained using the operating point of the gas turbine 16. Figure 5 is a graph showing the movement of the operating point of the gas turbine 16. The horizontal axis of the graph in Figure 5 represents the rotational speed of the gas turbine 16. The vertical axis of the graph in Figure 5 represents the output power of the gas turbine 16. The arrows in Figure 5 indicate the direction of movement of the operating point of the gas turbine 16.

[0034] At the start of power reduction control, the output power of the gas turbine 16 is P6 [W], and the rotational speed of the gas turbine 16 is N1 [rpm]. In this case, the operating point of the gas turbine 16 is located at point Q1. The target output power is P3 [W], and the target rotational speed for the target output power is N2 [rpm]. In this case, the operating point of the gas turbine 16 is located at point Q2.

[0035] The virtual operating point, determined by the target output power P3 [W] and the rotational speed N1 [rpm] of the gas turbine 16 at the start of output power reduction control, is located at point Q3. The virtual operating point Q3 is located above the misfire line. Therefore, the first output power reduction control is implemented.

[0036] In the first power reduction control, the requested power generation setting unit 47 first reduces the requested power generation, and the fuel injection amount setting unit 46 reduces the fuel injection amount. As a result, the output power of the gas turbine 16 decreases. In this case, the rotational speed of the gas turbine 16 hardly changes due to the inertia of the rotating elements of the gas turbine 16. As a result, the operating point of the gas turbine 16 moves from point Q1 to point Q3.

[0037] When the output power of the gas turbine 16 drops to the target output power P3 [W], the requested power generation setting unit 47 maintains the requested power generation, while the fuel injection amount setting unit 46 further reduces the fuel injection amount. When the fuel injection amount decreases, the output power of the gas turbine 16 temporarily decreases, and the gas turbine 16 decelerates. However, as the gas turbine 16 decelerates, the operating point of the gas turbine 16 approaches the SFC best line, and the output power of the gas turbine 16 recovers. Therefore, with the output power of the gas turbine 16 being maintained to some extent, the operating point of the gas turbine 16 moves from point Q3 towards point Q2.

[0038] When the rotational speed of the gas turbine 16 reaches the target rotational speed N2 [rpm], the requested power generation setting unit 47 maintains the requested power generation, and the fuel injection amount setting unit 46 maintains the fuel injection amount. As a result, the operating point of the gas turbine 16 is located at point Q2.

[0039] [Regarding the control of the second output power reduction] The second output power reduction control will be explained below. Figures 6A and 6B are diagrams illustrating the concept of the second output power reduction control. Figure 6A is a graph showing the time variation of the target output power of the gas turbine 16, the output power (actual output power) of the gas turbine 16, and the required power generation of the generator 18. Figure 6B is a graph showing the time variation of the target rotational speed of the gas turbine 16 and the rotational speed (actual rotational speed) of the gas turbine 16. Figures 6A and 6B conceptually illustrate the time variation of each element.

[0040] At time t4, the target output power decreases. Consequently, the target rotational speed decreases. From time t4 onward, the requested power generation setting unit 47 maintains the requested power generation power. At this time, the fuel injection amount setting unit 46 gradually reduces the fuel injection amount. As a result, the actual output power gradually decreases, and the gas turbine 16 gradually decelerates.

[0041] At time t5, the actual rotational speed decreases to the target rotational speed. After time t5, the requested power generation setting unit 47 gradually decreases the requested power generation. At this time, the fuel injection amount setting unit 46 further reduces the fuel injection amount. As a result, the actual output power gradually decreases. In this case, due to the inertia of the rotating elements of the gas turbine 16, the rotational speed of the gas turbine 16 hardly changes.

[0042] At time t6, the actual output power decreases to the target output power. At time t6, the requested power generation setting unit 47 maintains the requested power generation power, while the fuel injection amount setting unit 46 maintains the fuel injection amount. As a result, the hybrid controller 40 can set the output power of the gas turbine 16 to the target output power and the rotational speed of the gas turbine 16 to the target rotational speed.

[0043] The second output power reduction control will be explained using the operating point of the gas turbine 16. Figure 7 is a graph showing the movement of the operating point of the gas turbine 16. The horizontal axis of the graph in Figure 7 represents the rotational speed of the gas turbine 16. The vertical axis of the graph in Figure 7 represents the output power of the gas turbine 16. The arrows in Figure 7 indicate the direction of movement of the operating point of the gas turbine 16.

[0044] At the start of power reduction control, the output power of the gas turbine 16 is P6 [W], and the rotational speed of the gas turbine 16 is N1 [rpm]. In this case, the operating point of the gas turbine 16 is located at point Q1. The target output power is P2 [W], and the target rotational speed for the target output power is N3 [rpm]. In this case, the operating point of the gas turbine 16 is located at point Q4.

[0045] The virtual operating point, determined by the target output power P2 [W] and the rotational speed N1 [rpm] of the gas turbine 16 at the start of output power reduction control, is located at point Q5. The virtual operating point Q5 is located below the misfire line. Therefore, the second output power reduction control is implemented.

[0046] In the second output power reduction control, first, the requested power generation setting unit 47 maintains the requested power generation while the fuel injection amount setting unit 46 reduces the fuel injection amount. Subsequently, the requested power generation setting unit 47 reduces the requested power generation. As a result, the output power of the gas turbine 16 decreases and the gas turbine 16 decelerates. Consequently, the operating point of the gas turbine 16 shifts from point Q1 to point Q4.

[0047] [Regarding the time required for output power reduction control] As mentioned above, the first output power reduction control is performed when the virtual operating point is located above the misfire line, and not when the virtual operating point is located below the misfire line. The reason for this is that when the virtual operating point is located below the misfire line, the time required for the first output power reduction control is longer than the time required for the second output power reduction control.

[0048] The following describes the first output power reduction control when the virtual operating point is located below the misfire line.

[0049] Figure 8 is a graph showing the movement of the operating point of the gas turbine 16. The horizontal axis of the graph in Figure 8 represents the rotational speed of the gas turbine 16. The vertical axis of the graph in Figure 8 represents the output power of the gas turbine 16. The arrows in Figure 8 indicate the direction of movement of the operating point of the gas turbine 16.

[0050] At the start of power reduction control, the output power of the gas turbine 16 is P6 [W], and the rotational speed of the gas turbine 16 is N1 [rpm]. In this case, the operating point of the gas turbine 16 is located at point Q1. The target output power is P2 [W], and the target rotational speed for the target output power is N3 [rpm]. In this case, the operating point of the gas turbine 16 is located at point Q4.

[0051] The virtual operating point of the gas turbine 16, determined by the target output power P2 [W] and the rotational speed N1 [rpm] of the gas turbine 16 at the start of output power reduction control, is located at point Q5. This virtual operating point Q5 is located below the misfire line.

[0052] In the first power reduction control, the requested power generation setting unit 47 first reduces the requested power generation, and the fuel injection amount setting unit 46 reduces the fuel injection amount. As a result, the output power of the gas turbine 16 decreases. In this case, the rotational speed of the gas turbine 16 hardly changes due to the inertia of the rotating elements of the gas turbine 16. As a result, the operating point of the gas turbine 16 moves from point Q1 to point Q6. The operating point Q6 is located above the misfire line.

[0053] After the operating point of the gas turbine 16 moves to point Q6, the requested power generation setting unit 47 maintains the requested power generation, while the fuel injection amount setting unit 46 further reduces the fuel injection amount. When the fuel injection amount decreases, the output power of the gas turbine 16 temporarily decreases, and the gas turbine 16 decelerates. However, as the gas turbine 16 decelerates, the operating point of the gas turbine 16 approaches the SFC best line, and the output power of the gas turbine 16 recovers. Therefore, with the output power of the gas turbine 16 being maintained, the operating point of the gas turbine 16 moves from point Q6 towards point Q7.

[0054] After the operating point of the gas turbine 16 moves to point Q7, the requested power generation setting unit 47 reduces the requested power generation, and the fuel injection amount setting unit 46 reduces the fuel injection amount. As a result, the operating point of the gas turbine 16 moves from point Q7 to point Q8. The operating point Q8 is located above the misfire line.

[0055] After the operating point of the gas turbine 16 moves to point Q8, the requested power generation setting unit 47 maintains the requested power generation, while the fuel injection amount setting unit 46 further reduces the fuel injection amount. When the fuel injection amount decreases, the output power of the gas turbine 16 temporarily decreases, and the gas turbine 16 decelerates. However, as the gas turbine 16 decelerates, the operating point of the gas turbine 16 approaches the SFC best line, and the output power of the gas turbine 16 recovers. Therefore, with the output power of the gas turbine 16 being maintained, the operating point of the gas turbine 16 moves from point Q8 towards point Q4.

[0056] If the virtual operating point is located below the misfire line, the first power reduction control takes longer to reduce the output power of the gas turbine 16 to the target output power than the second power reduction control. As a result, the generator 18 generates more power than is consumed by the electric motor 36, leading to a problem of excessive surplus power.

[0057] Figure 9 is a table comparing the time required to reduce the output power of the gas turbine 16 to the target output power. Figure 9 shows the time required for the first output power reduction control and the time required for the second output power reduction control. In the "Condition" column of Figure 9, "Saved" indicates that the condition that the virtual operating point is located above the misfire line is met. In the "Condition" column of Figure 9, "Not Saved" indicates that the condition that the virtual operating point is located above the misfire line is not met.

[0058] As shown in Figure 9, if the condition that the virtual operating point is located above the misfire line is met, the time required for the first output power reduction control is shorter than the time required for the second output power reduction control. On the other hand, if the condition that the virtual operating point is located above the misfire line is not met, the time required for the first output power reduction control is longer than the time required for the second output power reduction control.

[0059] [Regarding the process of controlling output power reduction] Figure 10 is a flowchart showing the output power reduction control process. Output power reduction control is performed in the hybrid controller 40 from the time the gas turbine 16 is started until it is stopped.

[0060] In step S1, the hybrid controller 40 starts the power unit system 10. Then, the process proceeds to step S2.

[0061] In step S2, the hybrid controller 40 determines whether the power unit system 10 is functioning correctly. If the power unit system 10 is functioning correctly (step S2: YES), the process proceeds to step S3. If an abnormality occurs in the power unit system 10 (step S2: NO), the process proceeds to step S15.

[0062] In step S3, the hybrid controller 40 determines whether or not there is a request for a power reduction. If there is a request for a power reduction (step S3: YES), the process proceeds to step S4. If there is no request for a power reduction (step S3: NO), the process returns to step S2. If the target power is lower than the output power of the gas turbine 16, the hybrid controller 40 determines that there is a request for a power reduction.

[0063] In step S4, the condition determination unit 49 determines whether the operating point of the gas turbine 16 is located in the narrow movable region. If the operating point of the gas turbine 16 is located in the narrow movable region (step S4: YES), the process proceeds to step S10. If the operating point of the gas turbine 16 is not located in the narrow movable region (step S4: NO), the process proceeds to step S5.

[0064] In step S5, the condition determination unit 49 determines whether the virtual operating point of the gas turbine 16 is located above the misfire line. If the virtual operating point is located above the misfire line (step S5: YES), the process proceeds to step S6. If the virtual operating point is located below the misfire line (step S5: NO), the process proceeds to step S10.

[0065] Furthermore, if the virtual operating point is located on the misfire line, the system may proceed to step S6. Alternatively, if the virtual operating point is located on the misfire line, the system may proceed to step S10.

[0066] In steps S6 to S9 below, the first output power reduction control is performed. In step S6, the hybrid controller 40 reduces the output power of the gas turbine 16. After that, the process proceeds to step S7.

[0067] In step S7, the hybrid controller 40 determines whether the output power of the gas turbine 16 has reached the target output power. If the output power of the gas turbine 16 has reached the target output power (step S7: YES), the process proceeds to step S8. If the output power of the gas turbine 16 has not reached the target output power (step S7: NO), the process returns to step S6.

[0068] In step S8, the hybrid controller 40 reduces the rotational speed of the gas turbine 16. Then, the process proceeds to step S9.

[0069] In step S9, the hybrid controller 40 determines whether the rotational speed of the gas turbine 16 has reached the target rotational speed. If the rotational speed of the gas turbine 16 has reached the target rotational speed (step S9: YES), the process proceeds to step S14. If the rotational speed of the gas turbine 16 has not reached the target rotational speed (step S9: NO), the process returns to step S8.

[0070] In the following steps S10 to S13, second output power reduction control is performed. In step S10, the hybrid controller 40 reduces the rotational speed of the gas turbine 16. Then, the process proceeds to step S11.

[0071] In step S11, the hybrid controller 40 determines whether the rotational speed of the gas turbine 16 has reached the target rotational speed. If the rotational speed of the gas turbine 16 has reached the target rotational speed (step S11: YES), the process proceeds to step S12. If the rotational speed of the gas turbine 16 has not reached the target rotational speed (step S11: NO), the process returns to step S10.

[0072] In step S12, the hybrid controller 40 reduces the output power of the gas turbine 16. Then, the process proceeds to step S13.

[0073] In step S13, the hybrid controller 40 determines whether the output power of the gas turbine 16 has reached the target output power. If the output power of the gas turbine 16 has reached the target output power (step S13: YES), the process proceeds to step S14. If the output power of the gas turbine 16 has not reached the target output power (step S13: NO), the process returns to step S12.

[0074] In step S14, the hybrid controller 40 determines whether or not there is a request to stop the gas turbine 16. If there is a request to stop the gas turbine 16 (step S14: YES), the process proceeds to step S15. If there is no request to stop the gas turbine 16 (step S14: NO), the process returns to step S2.

[0075] In step S15, the hybrid controller 40 shuts down the power unit system 10. After that, the output power reduction control is terminated.

[0076] [Effects and Effects] If the output power of the gas turbine 16 is greater than the target output power, the generator 18 will generate more power than is consumed by the electric motor 36, resulting in surplus power. This surplus power is used to charge the battery 22. However, if the surplus power becomes excessive, there is a risk of overcharging the battery 22. Increasing the capacity of the battery 22 can suppress overcharging, but this presents the problem of increasing the size of the battery 22.

[0077] Therefore, in this embodiment, when reducing the output power of the gas turbine 16, if the virtual operating point is located above the misfire line, the hybrid controller 40 performs a first output power reduction control. On the other hand, if the virtual operating point is located below the misfire line, the hybrid controller 40 performs a second output power reduction control. This shortens the time required to reduce the output power of the gas turbine 16 to the target output power. As a result, the amount of surplus power can be suppressed. Consequently, overcharging of the battery 22 can be suppressed. In addition, the battery 22 can be made smaller.

[0078] Furthermore, the present invention is not limited to the embodiments described above, and various configurations can be taken without departing from the spirit of the invention.

[0079] [Invention obtained from the embodiment] The inventions that can be understood from the above embodiments are described below.

[0080] A control device (40) for a power unit system (10) comprising a gas turbine (16) having a compressor (24) and a turbine (28) that rotates integrally with the compressor, a generator (18) driven by the gas turbine, and a battery (22) for storing the electricity generated by the generator, wherein the control device comprises a demand power generation setting unit (47) for setting the demand power generation to the generator, a fuel injection amount setting unit (46) for controlling the amount of fuel injected into the combustion chamber (26) of the gas turbine, a target rotational speed setting unit (48) for setting the target rotational speed of the gas turbine for the target output power of the gas turbine, and a condition determination unit (49) for determining whether the relationship between the rotational speed of the gas turbine and the target output power satisfies predetermined conditions, wherein when the output power of the gas turbine is reduced, and the relationship between the rotational speed of the gas turbine and the target output power satisfies the predetermined conditions, the demand power generation setting unit determines whether the required power generation setting unit satisfies predetermined conditions When the power request is reduced and the fuel injection amount setting unit reduces the injection amount, thereby reducing the output power of the gas turbine to the target output power, and then the requested power generation setting unit maintains the requested power generation and the fuel injection amount setting unit reduces the injection amount, thereby decelerating the rotational speed of the gas turbine to the target rotational speed and reducing the output power of the gas turbine, if the relationship between the rotational speed of the gas turbine and the target output power does not satisfy the predetermined conditions, the requested power generation setting unit maintains the requested power generation and the fuel injection amount setting unit reduces the injection amount, thereby decelerating the rotational speed of the gas turbine to the target rotational speed, and then the requested power generation setting unit reduces the requested power generation and the fuel injection amount setting unit reduces the injection amount, thereby reducing the output power of the gas turbine to the target output power. This suppresses battery overcharging. It also allows for a smaller battery.

[0081] In the control device for the power unit system described above, at least one of the predetermined conditions may be that the virtual operating point, determined by the target output power and the rotational speed of the gas turbine before the output power of the gas turbine is reduced, is located above a predetermined misfire line that shows the relationship between the rotational speed of the gas turbine and the output power. This can suppress battery overcharging and allow for a smaller battery. [Explanation of Symbols]

[0082] 10…Power unit system 16…Gas turbine 18...Generator 22...Battery 24... Compressor 28... Turbine 40…Hybrid controller (control device) 46...Fuel injection amount setting unit 47...Required power generation setting unit 48...Target rotation speed setting unit 49...Condition determination unit

Claims

[Claim 1] A gas turbine having a compressor and a turbine that rotates integrally with the compressor, A generator driven by the aforementioned gas turbine, A battery for storing the electricity generated by the aforementioned generator, A control device for a power unit system, A power generation power setting unit that sets the required power generation power for the generator, A fuel injection amount setting unit that controls the amount of fuel injected into the combustion chamber of the gas turbine, A target rotational speed setting unit sets a target rotational speed for the gas turbine in relation to the target output power of the gas turbine, A condition determination unit that determines whether the relationship between the rotational speed of the gas turbine and the target output power satisfies predetermined conditions, Equipped with, The predetermined condition is that the virtual operating point, determined by the target output power and the rotational speed of the gas turbine before the output power of the gas turbine is reduced, is located above the misfire line, which is a predetermined relationship between the rotational speed of the gas turbine and the output power. When reducing the output power of the gas turbine, and the relationship between the rotational speed of the gas turbine and the target output power satisfies the predetermined conditions, The steps include: reducing the requested power generation setting unit to the requested power generation and reducing the fuel injection amount setting unit to the injection amount, thereby reducing the output power of the gas turbine to the target output power while maintaining the rotational speed of the gas turbine at the rotational speed before the reduction in the output power of the gas turbine; The steps include: reducing the rotational speed of the gas turbine to the target rotational speed while maintaining the output power of the gas turbine at the target output power by having the requested power generation setting unit maintain the requested power generation and the fuel injection amount setting unit reduce the injection amount; The first output reduction control is performed to carry out the following: When reducing the output power of the gas turbine, if the relationship between the rotational speed of the gas turbine and the target output power does not satisfy the predetermined conditions, The steps include: reducing the output power of the gas turbine and slowing down the rotational speed of the gas turbine to the target rotational speed by having the requested power generation setting unit maintain the requested power generation and the fuel injection amount setting unit reduce the injection amount; The steps include: reducing the requested power generation setting unit to the requested power generation and reducing the fuel injection amount setting unit to the injection amount, thereby reducing the output power of the gas turbine to the target output power and maintaining the rotational speed of the gas turbine at the target rotational speed; A control device for a power unit system that performs a second output reduction control.

Images