JP3808134B2 - Control device for gas turbine generator - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a control device for a gas turbine generator.
[0002]
[Prior art]
In a gas turbine generator driven by a gas turbine engine, an alternating current generated by the generator is converted into a direct current in an inverter, and chopping while monitoring the inverter output voltage with a transistor. (See Japanese Patent Laid-Open No. 59-2222099).
[0003]
As shown in FIG. 11, the control device provided in this type of gas turbine generator includes a direct current detection means 60 for detecting a direct current A converted by an inverter, and a direct current voltage detection means 61 for detecting a direct current voltage V. With. A power load L is calculated from the detected DC current A and DC voltage V, and a target engine speed Nset is searched based on a map 59 set in advance according to the power load L. Thus, feedback control of the fuel injection amount is performed so as to approach the target engine rotation speed corresponding to the electric power load L, and the fuel consumption is reduced by driving at the lowest rotation speed with respect to the electric power load. .
[0004]
[Problems to be solved by the invention]
By the way, in a generator using a permanent magnet, the generated voltage varies to some extent among individual generators due to variations in the magnetization of the permanent magnet.
[0005]
Also, the generated voltage tends to increase as the temperature of the permanent magnet decreases.
[0006]
However, in consideration of all conditions in which the generated voltage fluctuates, if the DC voltage V converted by the inverter is set so as not to exceed the upper limit determined from the withstand voltage of the electronic device, the range of change in the rotational speed of the engine However, there was a problem that the efficiency of the engine deteriorated as the size of the engine decreased. Alternatively, if a sufficient range of change in the rotational speed of the engine is to be ensured, there arises a problem that the withstand voltage standard required for the electronic device is increased to increase the cost of the product.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to improve the efficiency of an engine while suppressing a withstand voltage standard required for an electronic device in a control apparatus for a gas turbine generator.
[0008]
[Means for Solving the Problems]
The control device for a gas turbine generator according to claim 1 comprises:
A generator driven by a gas turbine engine;
A rectifier circuit that converts alternating current supplied from the generator into direct current;
An output side power conversion circuit that converts a direct current supplied from a rectifier circuit into an alternating current;
In the control device for the gas turbine generator comprising:
A power load detecting means 81 for detecting the power load L;
Target engine speed setting means 82 for setting a target engine speed Nset according to the power load L;
Engine rotation speed detection means 83 for detecting the engine rotation speed N;
Engine speed control means 84 for feedback-controlling the fuel injection amount so that the engine speed N approaches the target engine speed Nset;
DC voltage detecting means 85 for detecting the DC voltage V converted by the rectifier circuit;
DC current detection means 86 for detecting DC current A converted by the rectifier circuit;
Upper limit value setting means 87 for setting an upper limit value Nlimit according to the detected engine speed N, DC voltage V and DC current A;
Engine rotation speed limiting means 88 for limiting the fuel injection amount so that the engine rotation speed N does not exceed the upper limit value Nlimit;
Is provided.
[0009]
As shown in FIG. 13, the control device for the gas turbine generator according to claim 2
A power load detecting means 81 for detecting the power load L;
Target engine speed setting means 82 for setting a target engine speed Nset according to the power load L;
Engine rotation speed detection means 83 for detecting the engine rotation speed N;
Engine speed control means 84 for feedback-controlling the fuel injection amount so that the engine speed N approaches the target engine speed Nset;
An air temperature detecting means 91 for detecting an air temperature Tin sucked into the engine;
Starting upper limit value setting means 92 for setting an engine rotation speed upper limit value Nlimit according to the air temperature Tin at the time of starting;
Time limit setting means 93 for setting a time Time for limiting the fuel injection amount by the upper limit value Nlimit according to the air temperature Tin at the time of start;
Engine speed limiting means 94 for limiting the fuel injection amount so that the engine speed N does not exceed the upper limit value Nlimit until time Time elapses after starting;
Is provided.
[0010]
[Action]
In the gas turbine generator control device according to claim 1, by performing feedback control of the fuel injection amount so as to approach the target engine speed Nset set so as to decrease as the power load L decreases, The engine is operated at a rotational speed as low as possible with respect to the power load L.
[0011]
The engine rotation speed N is limited by the upper limit value Nlimit set according to the engine rotation speed N, the DC voltage V, and the DC current A, so that the rectifier circuit does not affect the magnetization variation of the permanent magnets. The operation is performed in such a range that the converted DC voltage V does not exceed the upper limit determined from the withstand voltage of the electronic device. For this reason, the withstand voltage standard required for the electronic device can be reduced to reduce the cost of the product, and the engine speed can be increased by increasing the variation range of the engine rotation speed.
[0012]
In the gas turbine generator control device according to claim 2, the feedback control of the fuel injection amount is performed so as to approach the target engine speed Nset set so as to decrease as the power load L decreases. The engine is operated at a rotational speed as low as possible with respect to the power load L.
[0013]
Coping with the fact that the engine rotation speed N is limited by the upper limit value Nlimit over the time Time corresponding to the air temperature Tin at the time of starting, so that the power generation voltage is significantly increased due to the temperature of the permanent magnet decreasing at extremely low temperatures. The DC voltage V converted by the rectifier circuit is operated in a range not exceeding the upper limit determined from the withstand voltage of the electronic device. For this reason, the withstand voltage standard required for the electronic device can be reduced to reduce the cost of the product, and the engine speed can be increased by increasing the variation range of the engine rotation speed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0015]
As shown in FIG. 1, a gas turbine engine 1 generates a high-temperature gas by heating a compressed air sent from the compressor 2 by combusting fuel inside the compressor 2 that sucks the atmosphere and compresses it to a required pressure. Combustor 3, turbine 4 that converts the energy of combustion gas emitted from combustor 3 into mechanical work, and compressed air sent from compressor 2 to combustor 3 by the heat of exhaust gas discharged from turbine 4 And a heat exchanger 5 for heating the
[0016]
In order to adjust the amount of fuel supplied to the combustor 3, a fuel adjustment valve 6 is provided. The fuel injection amount adjusted by the fuel adjustment valve 6 is controlled by a command from the controller 7.
[0017]
A three-phase AC generator 51 is directly connected to the turbine shaft 8 of the gas turbine engine 1. The three-phase AC generator 51 uses a permanent magnet.
[0018]
As shown in FIG. 2, the output from the winding wound around the stator of the generator 51 is supplied to the electric load 28 via the inverter 22.
[0019]
In FIG. 2, reference numeral 38 denotes an auxiliary machine provided in the gas turbine engine 1. The auxiliary machine 38 includes a fuel adjustment valve 6, a fuel pump (not shown), an oil pump, a fuel stop valve, and the like.
[0020]
The inverter 22 is built in the controller 7, drives the three-phase AC generator 51 as a starting motor at the time of starting, and supplies power to the power load 28 and the auxiliary device 38 after the starting is completed.
[0021]
The rectifier circuit 23 of the inverter 22 includes transistors 26a to 26f in parallel with six diodes 23a to 23f as a switching unit.
[0022]
When starting, the base current of each of the transistors 26a to 26f is ON / OFF controlled in accordance with a command from the controller 7, so that the current from the battery 41 is sent to the winding of the generator 51, and three-phase AC power generation is performed. The machine 51 is rotated.
[0023]
After the start, the transistors 26a, 26b, 26d, 26e, and 26f are turned off by the command from the controller 7, and only the diodes 23a, 23b, 23d, 23e, and 23f are operated, and the three-phase alternating current from the generator 51 is turned into direct current. Convert to current.
[0024]
The output side power conversion circuit 24 of the inverter 22 includes four transistors 24 a to 24 d in parallel with four diodes 24 e to 24 h as a switching unit, and an output side LC filter 27 is connected to the output of the output side power conversion device 24. The electrical load 28 is connected.
[0025]
After the start is completed, the base current of the four transistors 24a to 24d is ON / OFF controlled in a predetermined order according to a command from the controller 7, so that the DC current from the start three-phase power converter 23 is a single phase predetermined Convert to voltage AC output.
[0026]
As shown in FIG. 3, the controller 7 mainly composed of a microcomputer detects a detection signal of a sensor 18 that detects the rotational speed N of the turbine shaft 8 and an air temperature detection that detects an air temperature Tin sucked into the engine, which will be described later. The detection signal of the means 63 and the detection signal of the air pressure detection means 64 for detecting the air pressure Pin taken into the engine are input, and the operation of the gas turbine 1 is controlled.
[0027]
The controller 7 includes a direct current detection means 60 that detects a direct current A converted by the rectifier circuit 23 of the inverter 22 and a direct current voltage detection means 61 that detects a direct current voltage V.
[0028]
In the controller 7, the power load L is calculated from the detected DC current A and DC voltage V, and the target engine speed Nset is set based on a map 46 set in advance according to the power load L, the air temperature Tin, and the air pressure Pin. Is searched.
[0029]
Thus, feedback control of the fuel injection amount is performed so that the engine rotation speed N approaches the target engine rotation speed Nset corresponding to the power load L air temperature Tin and the air pressure Pin, and the operation is performed at a rotation speed as low as possible with respect to the power load. Thus, fuel consumption is reduced.
[0030]
FIG. 5 is a characteristic diagram showing the relationship between the power load and the generator voltage with respect to the engine speed. The power generation voltage increases substantially in proportion to the engine rotation speed, and decreases at each engine rotation speed as the power load (current amount) increases.
[0031]
Furthermore, in the generator 21 using permanent magnets, the generated voltage varies about 10% in the individual generators 21 due to variations in the magnetization of the permanent magnets.
[0032]
FIG. 6 is a characteristic diagram showing the relationship of the DC voltage V converted by the rectifier circuit 23 of the inverter 22 with respect to the amount of power load. Due to the peak hold characteristic of the smoothing circuit constituted by the capacitor 25, the direct current voltage V has a characteristic of rapidly increasing in a region close to a no-power load. Normally, the change in the DC voltage V is converted into an AC output having a predetermined voltage via the switching unit of the output side power conversion circuit 24.
[0033]
By the way, since the inverter 22 reduces the voltage of the DC part in the capacitor 25 by the switching part of the output side power conversion circuit 24 and converts it into an AC output voltage, the voltage of the DC part in the capacitor 25 is waveform-shaped into an AC peak voltage. It is necessary to increase it to a value higher than the added voltage. If the engine speed becomes too low, even if the DC voltage V is not sufficiently obtained, the inverter 22 is controlled so that the set AC output voltage value can be obtained. As a result, the AC output voltage waveform is crushed. The voltage waveform distortion rate representing the deviation with respect to the complete sine wave becomes large.
[0034]
Further, if the withstand voltage standard of the DC circuit in the inverter 22 is increased, the cost of the product is increased, and therefore there is a demand for setting the maximum voltage as low as possible.
[0035]
For this reason, as shown in FIG. 7, the DC voltage V converted by the rectifier circuit 23 of the inverter 22 is set so as not to exceed the upper limit determined from the withstand voltage of the electronic device and the lower limit determined from the voltage waveform distortion rate. The
[0036]
FIG. 8 is a characteristic diagram showing the relationship of the generated voltage with respect to the temperature of the permanent magnet constituting the generator 21. The generated voltage increases in proportion to the decrease in the temperature of the permanent magnet. For this reason, if the DC voltage V converted by the rectifier circuit 23 of the inverter 22 is set so as not to exceed the upper limit determined from the withstand voltage of the electronic device, the change rate of the engine rotational speed becomes small and the engine efficiency is reduced. There was a problem of getting worse. Alternatively, if a sufficient range of change in the rotational speed of the engine is to be ensured, there arises a problem that the withstand voltage standard required for the electronic device is increased to increase the cost of the product.
[0037]
In response to this, the present invention includes a map 45 in which an upper limit value Nlimit is set according to the detected engine speed N, DC voltage V, and DC current A, as shown in FIG. In the map 45, the upper limit value Nlimit is set so as to decrease as the engine speed N increases. In the map 45, the upper limit value Nlimit is set so as to decrease as the DC voltage V increases. In the map 45, the upper limit value Nlimit is set so as to decrease as the direct current A increases.
[0038]
A determination unit 65 is provided as an engine rotation speed limiting unit that limits the fuel injection amount so that the engine rotation speed N does not exceed the upper limit value Nlimit. The determination means 65 outputs the upper limit value Nlimit as the final target engine speed Nset when the target engine speed Nset searched based on the map 46 is higher than the upper limit value Nlimit.
[0039]
The flowchart of FIG. 4 shows a routine for calculating the target engine speed Nset of the gas turbine engine 1 executed by the controller 7.
[0040]
This will be described. First, in step 11, the direct current A detected by the direct current detection means 60 is read.
[0041]
Subsequently, in step 12, the DC voltage V detected by the DC voltage detecting means 61 is read.
[0042]
Subsequently, in step 13, the power load L is calculated as L = A × V from the detected DC current A and DC voltage V.
[0043]
Subsequently, at step 14, the rotational speed N detected by the rotational speed sensor 18 is read.
[0044]
Subsequently, in step 15, an upper limit value Nlimit is determined in accordance with the read engine speed N, DC voltage V, and DC current A based on a preset map 45. The processing performed in step 15 constitutes an upper limit setting unit.
[0045]
Subsequently, at step 16, the air temperature Tin taken into the engine detected by the air temperature detecting means 63 is read.
[0046]
Subsequently, at step 17, the air pressure Pin sucked into the engine detected by the air pressure detecting means 64 is read.
[0047]
Subsequently, at step 18, the target engine speed Nset is determined according to the power load L, the air temperature Tin, and the air pressure Pin based on the preset map 46. The processing performed in step 18 constitutes target engine speed setting means.
[0048]
Subsequently, in step 19, the smaller one of the read target engine speed Nset and upper limit value Nlimit is set as the final target engine speed Nset in the rotation speed control unit, and this routine ends.
[0049]
In this way, the engine rotational speed N is limited by the upper limit value Nlimit corresponding to the operating conditions, so that the DC voltage V converted by the rectifier circuit 23 of the inverter 22 is not affected by the magnetization variation of the permanent magnet. It operates within the range that does not exceed the upper limit determined by the withstand voltage of the electronic device. For this reason, the withstand voltage standard required for the electronic device can be reduced to reduce the cost of the product, and the engine speed can be increased by increasing the variation range of the engine rotation speed.
[0050]
Next, the embodiment shown in FIG. 9 will be described.
[0051]
In the controller, the power load L is calculated from the detected DC current A and DC voltage V, and the map 46 set in advance according to the power load L, the air temperature Tin, and the air pressure Pin is based on the detected DC current A and DC voltage V. The target engine speed Nset is retrieved.
[0052]
By the way, when the temperature of the permanent magnet is lowered at a very low temperature of about −30 ° C., for example, the generated voltage is significantly increased. For this reason, if the DC voltage V converted by the rectifier circuit of the inverter in response to extremely low temperatures is set so as not to exceed the upper limit determined from the withstand voltage of the electronic device, the range of change in the rotational speed of the engine is reduced. There is a problem that engine efficiency deteriorates. Alternatively, if a sufficient range of change in the rotational speed of the engine is to be ensured, there arises a problem that the withstand voltage standard required for the electronic device is increased to increase the cost of the product.
[0053]
The present invention copes with this, and includes a map 50 as a starting upper limit value setting means for determining the engine rotation speed upper limit value Nlimit based on the starting air temperature Tin. In the map 50, the engine rotational speed upper limit value Nlimit is set so as to decrease as the air temperature Tin at the time of starting decreases.
[0054]
A map 51 is provided as time limit setting means for setting a time Time for limiting the fuel injection amount so that the engine rotational speed N does not exceed the upper limit value Nlimit based on the air temperature Tin at the time of starting. In the map 51, the engine rotation speed upper limit value Nlimit is set so as to decrease as the air temperature Tin at the time of start-up decreases.
[0055]
A determination unit 66 is provided as an engine rotation speed limiting unit that limits the fuel injection amount so that the engine rotation speed N does not exceed the upper limit value Nlimit. The determination means 66 outputs the upper limit value Nlimit as the final target engine speed Nset when the target engine speed Nset searched based on the map 46 is higher than the upper limit value Nlimit.
[0056]
The flowchart of FIG. 10 shows a routine for calculating the target engine speed Nset of the gas turbine engine 1 executed in the controller.
[0057]
This will be described. First, in step 21, the air temperature Tin sucked into the engine detected by the air temperature detecting means 63 is read.
[0058]
Subsequently, at step 22, the engine speed upper limit value Nlimit is determined according to the air temperature Tin at the start based on a preset map 50. The processing performed in step 22 constitutes engine speed upper limit setting means after starting.
[0059]
Subsequently, in step 23, a time Time for limiting the fuel injection amount is determined based on the preset map 51 so that the engine speed N does not exceed the upper limit value Nlimit in accordance with the air temperature Tin at the time of start. . The processing performed at step 23 constitutes engine speed limit time setting means after starting.
[0060]
Subsequently, at step 24, the air pressure Pin sucked into the engine detected by the air pressure detecting means 64 is read.
[0061]
Subsequently, in step 25, the direct current A detected by the direct current detection means 60 is read.
[0062]
Subsequently, in step 26, the DC voltage V detected by the DC voltage detecting means 61 is read.
[0063]
Subsequently, in step 27, the power load L is calculated as L = A × V from the detected DC current A and DC voltage V.
[0064]
Subsequently, at step 28, the target engine speed Nset is determined according to the power load L, the air temperature Tin, and the air pressure Pin based on the map 46 set in advance.
[0065]
Subsequently, in step 29, the smaller one of the read target engine speed Nset and upper limit value Nlimit is set as the final target engine speed Nset in the speed controller, and this routine is terminated.
[0066]
In this way, the engine speed N is limited by the upper limit value Nlimit corresponding to the air temperature Tin at the time of starting, so that the power generation voltage is significantly increased due to the temperature of the permanent magnet being lowered at an extremely low temperature. The operation is performed in such a range that the DC voltage V converted by the rectifier circuit of the inverter does not exceed the upper limit determined from the withstand voltage of the electronic device. For this reason, the withstand voltage standard required for the electronic device can be reduced to reduce the cost of the product, and the engine speed can be increased by increasing the variation range of the engine rotation speed.
[0067]
【The invention's effect】
As described above, according to the control apparatus for a gas turbine generator according to claim 1, the engine speed N is limited by the upper limit value Nlimit set according to the engine speed N, the DC voltage V, and the DC current A. Therefore, the operation is performed in a range in which the DC voltage V converted by the rectifier circuit does not exceed the upper limit determined by the withstand voltage of the electronic device, without being affected by variations in magnetization of the permanent magnet. As a result, the withstand voltage standard required for the electronic device can be lowered to reduce the cost of the product, and the engine speed can be increased by increasing the variation range of the engine rotation speed.
[0068]
According to the control device for a gas turbine generator according to claim 2, since the engine rotational speed N is limited by the upper limit value Nlimit over the time Time corresponding to the air temperature Tin at the time of starting, the permanent magnet can be used at extremely low temperatures. In response to a significant increase in the generated voltage due to a decrease in temperature, the DC voltage V converted by the rectifier circuit is operated in a range that does not exceed the upper limit determined from the withstand voltage of the electronic device. As a result, the withstand voltage standard required for the electronic device can be lowered to reduce the cost of the product, and the engine speed can be increased by increasing the variation range of the engine rotation speed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a gas turbine generator showing an embodiment of the present invention.
FIG. 2 is an electric circuit diagram.
FIG. 3 is a block diagram of the controller.
FIG. 4 is a flowchart showing control details for calculating a target engine speed Nset.
FIG. 5 is a characteristic diagram showing the relationship between the power load and the generator voltage with respect to the engine speed.
FIG. 6 is a characteristic diagram showing the relationship of DC voltage V converted by the rectifier circuit of the inverter with respect to the amount of power load. FIG. 7 is also a characteristic diagram showing the setting range of DC voltage V.
FIG. 8 is a characteristic diagram showing the relationship between the generated voltage and the temperature of a permanent magnet that also constitutes the generator.
FIG. 9 is a block diagram of a controller showing another embodiment.
FIG. 10 is a flowchart showing control details for calculating a target engine speed Nset.
FIG. 11 is a block diagram of a controller showing a conventional example.
FIG. 12 is a view corresponding to claims of the invention according to claim 1;
13 is a view corresponding to claims of the invention according to claim 2. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas turbine engine 2 Compressor 3 Combustor 4 Turbine 5 Heat exchanger 6 Fuel adjustment valve 7 Controller 10 Voltage waveform distortion rate setting switch 21 Generator 22 Inverter 23 Rectifier circuit 24 Output side power conversion circuit 28 Electric load 50 DC voltage detection means 51 DC current detection means 55 Target voltage waveform distortion rate setting means 81 Power load detection means 82 Target engine rotation speed setting means 83 Engine rotation speed detection means 84 Engine rotation speed control means 85 DC voltage detection means 86 DC current detection means 87 Upper limit value Setting means 88 Engine rotational speed limiting means 91 Air temperature detecting means 92 Starting upper limit value setting means 93 Time limit setting means 94 Engine rotational speed limiting means

Claims (2)

A generator driven by a gas turbine engine;
A rectifier circuit that converts alternating current supplied from the generator into direct current;
An output side power conversion circuit that converts a direct current supplied from a rectifier circuit into an alternating current;
In a control device for a gas turbine generator comprising:
A power load detecting means for detecting the power load L;
Target engine speed setting means for setting a target engine speed Nset according to the electric power load L;
Engine rotation speed detection means for detecting the engine rotation speed N;
Engine speed control means for feedback-controlling the fuel injection amount so that the engine speed N approaches the target engine speed Nset;
DC voltage detecting means for detecting the DC voltage V converted by the rectifier circuit;
DC current detection means for detecting DC current A converted by the rectifier circuit;
Upper limit value setting means for setting an upper limit value Nlimit according to the detected engine speed N, DC voltage V and DC current A;
Engine rotation speed limiting means for limiting the fuel injection amount so that the engine rotation speed N does not exceed the upper limit value Nlimit;
A control device for a gas turbine generator, comprising: A generator driven by a gas turbine engine;
A rectifier circuit that converts alternating current supplied from the generator into direct current;
An output side power conversion circuit that converts a direct current supplied from a rectifier circuit into an alternating current;
In a control device for a gas turbine generator comprising:
A power load detecting means for detecting the power load L;
Target engine speed setting means for setting a target engine speed Nset according to the electric power load L;
Engine rotation speed detection means for detecting the engine rotation speed N;
Engine speed control means for feedback-controlling the fuel injection amount so that the engine speed N approaches the target engine speed Nset;
An air temperature detecting means for detecting an air temperature Tin sucked into the engine;
Starting upper limit value setting means for setting an engine rotation speed upper limit value Nlimit according to the air temperature Tin at the time of starting;
Time limit setting means for setting a time Time for limiting the fuel injection amount by the upper limit value Nlimit according to the air temperature Tin at the time of start;
Engine rotation speed limiting means for limiting the fuel injection amount so that the engine rotation speed N does not exceed the upper limit value Nlimit while the time Time elapses after starting;
A control device for a gas turbine generator, comprising:

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