JP6334291B2 - Exciter for AC exciter - Google Patents

Description

  The present invention relates to an exciter for an AC exciter used for starting a power generator composed of a gas turbine and a generator.

  In recent years, there has been a demand for higher efficiency of power generation facilities from the viewpoint of the environment, and for this reason, combined cycle power generation using a gas turbine (GT) is increasing. Against this background, the capacity of gas turbines is increasing.

  In the gas turbine, combustion air is compressed by a rotary compressor and sent to a combustor, fuel is blown into the combustor and burned, and the turbine is rotated by high-temperature and high-pressure combustion gas generated at that time. The turbine shaft is directly connected to the compressor, and continuously transmits the compressor power to the compressor. For this reason, in starting the gas turbine, it is necessary to drive a compressor and a generator having a large resistance torque by a starting electric motor or the like until the rotational speed at which the gas turbine ignites and can operate independently is reached.

Under these circumstances, the starter motor and torque converter, which are scaled up according to the increase in capacity of the power generation equipment, are not required, and there is no voltage drop of the in-house power supply due to the start current of the motor, and the shaft dimensions can be shortened. A method of starting a gas turbine by using a variable speed inverter device to convert the frequency of a commercial power source and using the generator itself as a synchronous motor is increasing.
At this time, it is necessary to energize the field winding of the starting motor with an excitation current of about several hundred A from the turning speed (several times / min) to the rated speed. In the brushless excitation method, there is a problem that in the region where the rotational speed is low, such as several times / min, the AC generated voltage of the AC exciter is small and sufficient excitation cannot be performed. For this reason, thyristor excitation that can excite a field winding by using a slip ring regardless of the rotation speed is generally used.

  The AC exciter used in the brushless excitation method generates a magnetic flux by passing a current through the field winding, and the armature winding of the AC exciter that is directly connected to the field winding of the generator by the rotating shaft The excitation power necessary for power generation is generated by interlinking with the magnetic flux. When the AC exciter is a synchronous machine, DC is generally used as the voltage applied to this field winding, but a three-phase winding induction machine is applied as the AC exciter, and the primary field winding By using a three-phase winding and applying an AC voltage, an AC voltage is generated on the secondary side. Such excitation makes it possible to start up the variable speed inverter device, which was difficult with the conventional brushless excitation method (for example, Patent Document 1).

JP 2003-143899 A

  FIG. 21 is a circuit configuration diagram of a conventional turbine generator with a brushless exciter in which a three-phase induction machine is used as an AC exciter and the gas turbine generator can be started by a variable speed inverter. At start-up, the three-phase AC voltage generated in the armature winding 11 is rectified by the diode of the rotary rectifier 12 to become DC. The DC terminal of the rotary rectifier 12 is connected to the field winding 21 of the main generator 2 within the rotor 4, and the field winding 21 of the main generator 2 is a rotor having magnetic poles in a certain direction. 4 For this reason, a variable speed inverter 23 for starting is connected to the armature winding 22 of the main generator 2, a variable speed power source is created by using the in-house power supply 71 as an input, and the armature winding 22 of the main generator 2 is connected to the armature winding 22. If a rotating magnetic field is created and the speed is gradually increased from a low frequency, the main generator can be started as a synchronous motor without providing a special acceleration motor.

  Further, after startup and during normal operation, the excitation rectifier 43 uses the AC voltage of the permanent magnet generator (PMG) 40 as a power source and rectifies the AC to DC by the thyristor rectifier, and the field winding 18 of the AC exciter 9. As a result of the DC excitation, a three-phase AC voltage is generated in the armature winding 11 and becomes DC in the rotary rectifier 12 in the same manner as at the start-up, and a current flows in the field winding 21 of the main generator 2. A voltage is generated in the second armature winding 22, and then synchronously inserted into the system power supply 72.

  However, the excitation device of the conventional AC exciter needs to establish the excitation of the field winding of the main generator when starting up with the variable speed inverter device. Therefore, at startup, it is necessary to excite the field winding of an AC exciter using a three-phase induction machine with AC excitation, and then to perform DC excitation when the gas turbine reaches its speed near the rating by self-sustaining operation. There is. For this reason, a three-phase current regulator for activation and a thyristor and an excitation rectifier device used after activation are required as an excitation device for an AC exciter. Therefore, a contactor for switching to an AC excitation contactor and a DC excitation rectifier are essential, and there is a problem that the output circuit has a complicated configuration.

  The present invention has been made to solve the above-described problems. In the excitation by the AC exciter, the advantage of the brushless excitation generator that does not require a slip ring or a brush for supplying DC to the rotor is utilized. On the other hand, an object of the present invention is to obtain an exciter for an AC exciter having a simple configuration that can start a gas turbine with a variable speed inverter.

In order to solve the above-mentioned problems, an excitation device for an AC exciter according to the present invention supplies current to each of the field windings of a synchronous machine which is an AC exciter having two-axis field windings. A single-phase inverter composed of a plurality of switching elements, and a converter that converts alternating current into direct current and supplies direct-current power to the single-phase inverter. In the case of alternating current excitation, the single-phase inverter is operated as an inverter. In the case of DC excitation, the single-phase inverter is operated as a chopper, and excitation power is supplied to the generator by the synchronous machine.

  According to the excitation device of the AC exciter of the present invention, since the excitation device is composed of two single-phase inverters, the operation of the excitation device can be made to respond at a higher speed than the conventional current regulator, In addition, at the time of start-up, excitation can be established in the field winding of the main generator even during low-speed rotation, and the circuit can be simplified by using the same excitation device for excitation even during normal operation. is there.

The block diagram of the gas turbine electric power generation system by the alternating current exciter provided with the excitation apparatus which concerns on Embodiment 1 is shown. The circuit diagram of the single phase inverter of the excitation device which concerns on Embodiment 1 is shown. FIG. 3 is a circuit diagram illustrating an operation of a single-phase inverter to which field windings are connected in an AC excitation operation of the excitation device according to the first embodiment. It is a figure which shows the inverter operation | movement and output waveform of a single phase inverter by the PWM waveform generation method (at the time of a high voltage) in Embodiment 1. FIG. It is a figure which shows the inverter operation | movement and output waveform of a single phase inverter by the PWM waveform generation method (at the time of a low voltage) in Embodiment 1. FIG. FIG. 3 is a circuit diagram illustrating an operation of a single-phase inverter in a direct current excitation operation of the excitation device according to the first embodiment. It is a figure which shows the output waveform of the single phase inverter in the direct current excitation operation | movement of the excitation apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the operation | movement logic circuit of the single phase inverter from starting of the excitation apparatus which concerns on Embodiment 1 to rated operation. FIG. 10 is a circuit diagram illustrating an operation of a single-phase inverter in a direct current excitation operation of the excitation device according to the second embodiment. It is a figure which shows the output waveform of the single phase inverter in the direct current excitation operation | movement of the excitation apparatus which concerns on Embodiment 2. FIG. FIG. 10 is a diagram illustrating an operation logic circuit of a single-phase inverter in a direct current excitation operation of the excitation device according to the second embodiment. It is a figure which shows the operation mode logic circuit of the single phase inverter of the excitation device which concerns on Embodiment 3. FIG. It is a figure which shows the operation mode logic circuit of the single phase inverter of the excitation device which concerns on Embodiment 4. FIG. 10 is a vector diagram of excitation current in the excitation device according to Embodiment 5. FIG. 10 is a circuit diagram showing a connection between a single-phase inverter and a field winding according to a fifth embodiment. FIG. 10 is a schematic circuit configuration diagram illustrating an entire gas turbine power generation system using an AC exciter including an excitation device according to Embodiment 6. FIG. 10 is a control block circuit diagram showing a control system using an AC exciter equipped with an excitation device according to Embodiment 7. It is a figure which shows the relationship between the rotation speed of the alternating current exciter in the excitation apparatus which concerns on Embodiment 8, and an excitation frequency. It is a figure which shows operation | movement of the single phase inverter in direct current excitation operation | movement of the excitation apparatus which concerns on Embodiment 9. FIG. FIG. 20 is a diagram illustrating an operation logic circuit of a single-phase inverter in a direct current excitation operation of the excitation device according to the ninth embodiment. The block diagram of the gas turbine power generation system by the alternating current exciter provided with the conventional excitation apparatus is shown.

Embodiment 1 FIG.
In the first embodiment, as an AC exciter, a synchronous machine having two field windings of d-axis and q-axis is applied to a brushless excitation type exciter. Embodiment 1 of the present invention will be described below with reference to FIGS.
FIG. 1 is a schematic circuit configuration diagram showing an entire gas turbine power generation system using an AC exciter including the excitation device according to Embodiment 1, and FIG. 2 shows a circuit diagram of a single-phase inverter of the excitation device. FIG. 3 shows a circuit diagram of a single-phase inverter to which field windings are connected.

  First, the configuration of a gas turbine power generation system using an AC exciter including the excitation device according to Embodiment 1 will be described with reference to FIG. In FIG. 1, a gas turbine power generation system 1 using an AC exciter 9 having an excitation device 3 includes a gas turbine 27, a main generator 2 connected to a rotor 28 of the gas turbine 27 by a rotating shaft 45, and a three-phase AC. It comprises a rotary rectifier 12 that converts a current into a direct current and energizes the field winding 21 of the main generator 2, an armature winding 11, a d-axis field winding 16, and a q-axis field winding 17. The AC exciter 9 for energizing the rotary rectifier 12 with the three-phase AC current generated by the armature winding 11, the excitation device 3 for driving the AC exciter 9 when the main generator 2 is started, and the excitation device 3 And an excitation power source 73 for supplying current. Here, the rotating shaft 45 of the field 46 of the permanent magnet generator (hereinafter referred to as PMG) 40 is mechanically coupled to the armature winding 11 of the AC exciter 9. The rotary shaft 45 is also mechanically connected to the rotary rectifier 12 and the field winding 21 of the main generator 2, and these constitute a rotor 4 that rotates integrally.

  In addition, at the time of start-up, in order to drive the main generator 2 as a synchronous motor, the in-house power source 71 as a power source for energizing the armature winding 22 of the main generator 2 and the power of the in-house power source 71 can be converted. A variable speed inverter device (or thyristor starting device) 23 and a starting contactor S1 for connecting the variable speed inverter 23 and the armature winding 22 are provided.

  Further, after the start-up is completed, a system breaker S2 that connects the power generated by the armature winding 22 of the main generator 2 by the gas turbine 27 to the system, and a system interconnection transformer 24 that transforms the power in accordance with the system, And a system power source 72 which is a connection destination for transmitting the generated power.

  The excitation device 3 includes a converter 41 that converts the alternating current of the excitation power source 73 to direct current when the contactor S5 for activation is connected when the main generator 2 is activated, and further converts the direct current into alternating current to convert the d axis of the alternating current exciter 9 A single-phase inverter 31 and a single-phase inverter 32 that energize each of the field winding 16 and the q-axis field winding 17 are configured. When the d-axis field winding 16 and the q-axis field winding 17 are energized, the armature winding 11 that is the rotor of the AC exciter 9 is rotationally driven, and the main generator 2 is driven. It is activated. As shown in FIG. 2, the single-phase inverters 31 and 32 are configured by four IGBT modules 51 to 54 as switching elements. Further, DC capacitors 34 and 35 connected in series are arranged in parallel on the input side of the IGBT modules 51 to 54.

  The AC exciter 9 includes an armature winding 11 that is a rotor, a d-axis field winding 16 and a q-axis field winding 17 that are stators. As described above, the field 46 of the PMG 40 and the rotating shaft 45 are mechanically connected. After the start-up of the main generator 2 and during normal operation, the starting contactor S5 is switched to the normal contactor S6, and the field 46 of the PMG 40 is rotated by the rotation of the armature winding 11, thereby The three-phase alternating current generated in the armature 47, which is the stator of the PMG 40, is energized in the excitation device 3.

  Next, the operation of the excitation device for an AC exciter according to Embodiment 1 will be described with reference to FIGS.

1) Inverter operation (AC excitation operation) of single phase inverter of excitation device at start-up, operation of AC exciter and main generator <Operation of excitation device at start-up>
The operation of the excitation device at the time of starting the gas turbine power generation system 1 will be described. At the time of start-up, the connection state of the power source to the exciter 3 of the AC exciter 9 is such that the start contactor S5 is on (ON) and the normal contactor S6 is off (OFF).

  The converter 41 converts alternating current of the excitation power source 73 into direct current. Further, based on the direct current of converter 41, single-phase inverter 31 causes the switching elements of IGBT modules 51 to 54 to operate as inverters to generate alternating current and excite d-axis field winding 16 of alternating current exciter 9. Similarly, the single-phase inverter 32 causes the switching elements of the IGBT modules 51 to 54 to operate as inverters to generate alternating current and excite the q-axis field winding 17 of the alternating current exciter 9. Here, the d-axis field winding 16 and the q-axis field winding 17 of the AC exciter 9 have a phase difference of 90 degrees. For this reason, the phase difference between the output voltage of the single-phase inverter 31 and the output voltage of the single-phase inverter 32 is about 90 degrees as in the d-axis field winding 16 and the q-axis field winding 17 of the AC exciter 9. Has a phase difference.

<Inverter operation of single-phase inverter (AC excitation operation)>
Next, the circuits of the single-phase inverters 31 and 32 used in the excitation device 3 of the AC exciter 9 and the inverter operation (AC excitation operation) will be described. As shown in FIG. 2, the single-phase inverters 31 and 32 are each composed of four IGBT modules 51 to 54 as switching elements, and are connected in series to the input side of these IGBT module groups in order to smooth the voltage pulsation. The DC capacitors 34 and 35 are arranged in parallel. The output terminal a of the IGBT modules 51 and 52 and the output terminal b of the IGBT modules 53 and 54 are outputs, and the two single-phase inverters 31 and 32 are respectively connected to the d-axis field winding 16 and the q-axis field winding. 17 is connected.

  The IGBT modules 51, 52, 53, and 54 are configured by IGBT elements 55, 56, 57, and 58 and diode elements 59, 60, 61, and 62, respectively. That is, each IGBT module has a configuration based on a combination of one IGBT element and one diode element connected in antiparallel. The IGBT module can energize the current between the collector (C) and the emitter (E) by applying an ON signal to the gate (G).

  FIG. 3 is a circuit diagram showing the operation of the single-phase inverter to which the field winding is connected in the AC excitation operation of the excitation device at start-up, and FIG. 4 is a PWM (Pulse Width Modulation) waveform generation method (at high voltage). ) Shows an example of operating a single-phase inverter as an inverter. FIG. 4 shows an example of an output current waveform when the output voltage of the single-phase inverters 31 and 32 is large (at the time of high voltage). In FIG. 3, the d-axis field winding 16 or the q-axis field winding 17 of the AC exciter 9 is connected to the output terminals a and b of the single-phase inverters 31 and 32, respectively. Here, FIG. 4 shows a voltage waveform with reference to the midpoint 37 when the DC voltage E that is the output of the converter 41 is two series power supplies of ± (E / 2).

  As shown in FIG. 4A, the triangular wave carrier (modulated wave) signal and the output sine wave signal are compared, and when the output sine wave signal is larger than the carrier signal, the gate of the IGBT module 51 on the positive electrode side. When the output sine wave signal is small, the gate of the negative-side IGBT module 52 is turned on. The PWM waveform generated by this is shown in FIG. In FIG. 3, the IGBT module 51 and the IGBT module 54 are turned on / off at the same gate timing, and the IGBT module 52 and the IGBT module 53 are turned on / off at the same gate timing. Here, the IGBT module 51 and the IGBT module 54 (or the IGBT module 52 and the IGBT module 53) are not simultaneously turned on because a direct current is short-circuited.

  4 shows the gate signal waveforms of the IGBT module 51 and the IGBT module 54, the gate signal waveforms of the IGBT module 52 and the IGBT module 53, the voltage waveform Va of the output terminal a, the voltage waveform Vb of the output terminal b, and the output terminal a−. a voltage waveform Vab between b (voltage when the output terminal a is viewed with reference to the output terminal b), and current when the d-axis field winding 16 or the q-axis field winding 17 of the AC exciter 9 is used as a load. An example of the waveform I0 is shown.

  In FIG. 4, the voltage waveform Va at the output terminal a is (+ E / 2) when the gates of the IGBT module 51 and the IGBT module 54 are on, and the gates of the IGBT module 52 and the IGBT module 53 are on. In such a case, the voltage waveform Vb of the output terminal b becomes (+ E / 2) when the gates of the IGBT module 52 and the IGBT module 53 are ON, and the voltage waveform Vb of the output terminal b becomes the IGBT module. When the gates of 51 and IGBT module 54 are on, the voltage is (−E / 2). The voltage waveform Vab between the output terminals a and b can be calculated from Va and Vb.

  FIG. 5 shows an example in which a single-phase inverter is operated as an inverter by a PWM waveform generation method (at a low voltage). As in the case of high voltage, as shown in FIG. 5 (a), a triangular wave carrier (modulated wave) signal is compared with an output sine wave signal. The gate of the IGBT module 51 on the side is turned on, and when the output sine wave signal is small, the gate of the IGBT module 52 on the negative electrode side is turned on. The PWM waveform generated by this is shown in FIG. Here, the output sine wave signal is made smaller than the triangular wave carrier signal to obtain a gate signal.

  5 shows the gate signal waveforms of the IGBT module 51 and the IGBT module 54, the gate signal waveforms of the IGBT module 52 and the IGBT module 53, the voltage waveform Va of the output terminal a, the voltage waveform Vb of the output terminal b, and the output terminal a−. The voltage waveform Vab between b (= Va−Vb) (the voltage when the output terminal a is viewed with reference to the output terminal b), and the d-axis field winding 16 or the q-axis field winding 17 of the AC exciter 9 An example of a current waveform I0 when a load is used is shown.

  That is, by reducing the output sine wave signal, the on-period of the voltages Va and Vb is shortened, so that the fundamental frequency component of the voltage Vab (= Va−Vb) is reduced.

  In the above description, for the sake of simplicity, the midpoint 37 of the DC capacitors 34 and 35 connected in series has been described as a voltage reference. However, in an actual circuit, the operation does not change even if it is not grounded. A filter may be inserted to reduce output harmonics of the single-phase inverters 31 and 32. In addition, although the DC capacitors 34 and 35 are used as capacitors, capacitors that can be used with AC may be used.

<Operation at the time of starting the main generator>
Next, the operation at the time of starting the main generator 2 will be described. Here, in FIG. 1, the start-up contactor S5 is turned on, the normal contactor S6 is turned off, the converter 41 receives the excitation power supply 73 and converts an alternating voltage into a direct voltage, and the single-phase inverters 31 and 32 are The inverter 41 converts the DC voltage of the converter 41 into an AC voltage. By the operation of the single-phase inverters 31 and 32, AC excitation is performed from the excitation device 3 to the d-axis field winding 16 and the q-axis field winding 17 of the AC exciter 9. As a result, even in the case of a low rotational speed, a three-phase AC voltage is induced in the armature winding 11 of the AC exciter 9 and is further converted to DC by the rotary rectifier 12. Excitation can be established in the magnetic winding 21.

  Here, the main generator 2 is a synchronous machine and can also function as a synchronous motor. For this reason, if the variable speed inverter 23 is connected to the armature winding 22 of the main generator 2 and driven, the main generator 2 can be started as a synchronous motor. That is, the starting variable speed inverter 23 creates a variable speed power supply using the in-house power supply 71 as an input power supply, and gradually increases the rotating magnetic field of the armature winding 22 of the main generator 2 from a low frequency. Since the field winding 21 has already been excited by the AC exciter 9, the rotational speed of the main generator 2 increases in synchronization with the rotating magnetic field.

2) Chopper operation (DC excitation operation) of single-phase inverter of exciter after startup and normal operation, operation of AC exciter and main generator <Chopper operation of single-phase inverter (DC excitation operation)>
Next, the circuits of the single-phase inverters 31 and 32 and their chopper operations (DC excitation operations) will be described.

  FIG. 6 is a circuit diagram showing the operation of the single-phase inverter in the DC excitation operation of the excitation device during normal operation, and FIG. 7 shows the output waveform of the single-phase inverter in the DC excitation operation of the excitation device. In FIG. 6, the IGBT module 51 is turned on / off, the IGBT module 54 is always on, and the IGBT modules 52 and 53 are always off. Here, in the figure, the solid line circles indicate the on / off switching operation of the IGBT module, the solid line squares indicate the always on operation, and the broken line squares indicate the always off operation. In this circuit operation, a DC voltage is turned on / off by the IGBT element 55 of the IGBT module 51, and the voltage can be adjusted by the ratio of the ON period of the IGBT element within a certain period. Vab is a positive voltage. FIG. 7 shows waveforms when the single-phase inverter 31 or 32 is chopper-operated (plus operation) and a positive voltage (+) is output to the output terminal a and a negative voltage (−) is output to the output terminal b.

  7 shows the gate signal waveform of the IGBT module 51, the gate signal waveform of the IGBT module 54, the gate signal waveform of the IGBT module 52 and the IGBT module 53, the voltage waveform Va of the output terminal a, the voltage waveform Vb of the output terminal b, The voltage waveform Vab (= Va−Vb) between the output terminals a and b (the voltage when the output terminal a is viewed with reference to the output terminal b), and the d-axis field winding 16 or the q-axis field of the AC exciter 9 Examples of the current waveform I0 when the winding 17 is a load are shown. Here, the middle point 37 of the DC capacitor was used as a voltage reference.

  In FIG. 7, the gates of the IGBT module 52 and the IGBT module 53 are always off. The voltage waveform Va at the output terminal a is (+ E / 2) when the gate of the IGBT module 51 is on, and is (−E / 2) when it is off, and the voltage waveform at the output terminal b. Vb is a constant voltage (−E / 2). The voltage waveform Vab between the output terminals a and b can be calculated from Va and Vb. The current waveform I0 increases as the voltage waveform Vab increases to the positive side, and is constantly at a current value determined from the resistance R and the voltage V of the field windings 16 and 17.

<Operation of main generator after startup>
As described above, in FIG. 1, the main generator 2 operates as a synchronous motor at the time of start-up, but when the gas turbine 27 is ignited and operates autonomously and continuously reaches a certain rotational speed, the variable speed inverter device 23. Is stopped, the starting contactor S1 is turned off, and the excitation of the field windings 16 and 17 is stopped, so that the single-phase inverters 31 and 32 performing the AC excitation operation are stopped and the converter 41 is stopped. It becomes. Thereafter, the normal contactor S6 is turned on and the starting contactor S5 is turned off near the rated speed, whereby the input power source of the exciter 3 is changed from the excitation power source 73 to the power source generated by the armature 47 of the PMG 40. Switch. Here, a permanent magnet is used for the field 46 of the PMG 40, and three-phase AC power using the permanent magnet as a rotor is generated in the armature 47 of the PMG 40. The converter 41 uses the three-phase AC power of the PMG 40 as a power source, rectifies AC to DC, and supplies DC power to the single-phase inverters 31 and 32.

  As described above, the single-phase inverters 31 and 32 receive the direct current from the converter 41 by the chopper operation, perform DC / DC voltage conversion, and perform the d-axis field winding 16 and the q-axis field of the AC exciter 9. By exciting the magnetic winding 17 with a direct current, a three-phase alternating current is generated in the armature winding 11 and converted into a direct current by the rotary rectifier 12 in the same manner as at the start-up. 21 is energized, AC power is generated in the armature winding 22 of the main generator 2, and then synchronously inserted into the system power supply 72 via the circuit breaker S <b> 2 and the system interconnection transformer 24.

  FIG. 8 shows an operation logic circuit of the single-phase inverters 31 and 32 from the start of the main generator 2 to the rated operation. The operation logic circuit includes NOT logic 75, 76, 77 and AND logic 78, 79. The inverter operation command is output as an AND logic 78 including a NOT logic 75 for a start command, a start completion command, and a NOT logic 77 for a DC excitation on command. The chopper operation command is output as AND logic 79 of the start command NOT logic 76, the start completion command, and the DC excitation on command.

  As described above, according to the excitation device of the AC exciter according to the first embodiment, the excitation device can be shared between the AC excitation at the time of activation and the DC excitation after the activation is completed. There is no need to provide a contactor for switching the circuit after completion, a simple output circuit configuration can be achieved, and both the d-axis field excitation and the q-axis field excitation of the AC exciter can be changed at the same time, thereby improving the control accuracy. This can improve the speed and speed of control response.

  In the above description, the single-phase inverter 31 and the single-phase inverter 32 are connected so as to share the DC output of the converter 41, but a converter may be provided for each single-phase inverter. In addition, in the circuit diagram of the single-phase inverters 31 and 32, it is described that the connection point 37 (middle point) of the DC capacitors 34 and 35 connected in series is grounded. It may be ungrounded. Further, in the circuit diagram of the single-phase inverters 31 and 32, the DC capacitors 34 and 35 have been described as being disposed in the single-phase inverters 31 and 32. May be installed.

  In the above description, the switching operation has been described by the PWM (Pulse Width Modulation) method. However, it is only necessary to be able to generate a voltage between the output terminals a and b which are load terminals, and other switching methods. It may be.

  In the above description, the case where the PGM 40 is used as the generator for excitation has been described, but another generator may be used.

Embodiment 2. FIG.
FIG. 9 is a circuit diagram showing the operation of the single-phase inverter to which the field winding is connected in the DC excitation operation of the excitation device of the AC exciter according to Embodiment 2, and FIG. 10 is the DC excitation of the excitation device. The output waveform of the single phase inverter in operation is shown. The difference from the circuit diagram showing the operation of the single-phase inverter in the direct current excitation operation of the excitation device according to Embodiment 1 shown in FIG. 6 is that the IGBT module that performs the on / off switching operation is different. Since the circuit diagram of the single-phase inverter is the same as that of the first embodiment, the description thereof is omitted.

Next, the circuit of single phase inverters 31 and 32 and the chopper operation (DC excitation operation) in the second embodiment will be described.
In FIG. 9, the IGBT module 53 is turned on / off, the IGBT module 52 is always turned on, and the IGBT modules 51 and 54 are always turned off. Here, in the figure, the solid line circles indicate the on / off switching operation of the IGBT module, the solid line squares indicate the always on operation, and the broken line squares indicate the always off operation. In this circuit operation, a DC voltage is turned on / off by the IGBT element 57 of the IGBT module 53, and the voltage can be adjusted by the ratio of the ON period of the IGBT element within a certain period. Note that unlike the first embodiment, Vab is a negative voltage. FIG. 10 shows waveforms when the single-phase inverter 31 or 32 is chopper-operated (minus operation) to output a negative voltage (−) to the output terminal a and a positive voltage (+) to the output terminal b.

  FIG. 10 shows a gate signal waveform of the IGBT module 53, a gate signal waveform of the IGBT module 52, a gate signal waveform of the IGBT module 51 and the IGBT module 54, a voltage waveform Va of the output terminal a, a voltage waveform Vb of the output terminal b, The voltage waveform Vab (= Va−Vb) between the output terminals a and b (the voltage when the output terminal a is viewed with reference to the output terminal b), and the d-axis field winding 16 or the q-axis field of the AC exciter 9 Examples of the current waveform I0 when the winding 17 is a load are shown. Here, the middle point 37 of the DC capacitor was used as a voltage reference.

  In FIG. 10, the gates of the IGBT module 51 and the IGBT module 54 are always off. The voltage waveform Va at the output terminal a is always (−E / 2), and the voltage waveform Vb at the output terminal b is (+ E / 2) when the gate of the IGBT module 53 is on, and is off. In this case, the voltage is (−E / 2). The voltage waveform Vab between the output terminals a and b can be calculated from Va and Vb. The current waveform I0 decreases as the voltage waveform Vab increases to the negative side, and steadily, the current value determined from the resistance R of the d-axis field winding 16 or the q-axis field winding 17 and the voltage V Become.

  By switching the operation of each IGBT module, the voltage waveform Vab between the output terminals a and b can be set to a negative voltage, whereby the d-axis field winding 16 and the q-axis field winding 17 are changed. The exciting current flowing through the coil can be rapidly reduced and demagnetized.

  FIG. 11 shows an operation logic circuit of the single-phase inverters 31 and 32 in the DC excitation operation of the excitation device in which the chopper (plus) operation is added to the chopper (plus) operation of the first embodiment. Indicates. A comparator (comparator) 83, a NOT logic 80, and AND logics 81 and 82 are added. The logic circuit 87 is the same logic circuit as in FIG. 8, and compares the analog excitation command with the positive / negative judgment criterion (0). The output of the comparator 83 is “1” when the excitation command is larger than the positive / negative judgment criterion, and “0” when the excitation command is smaller. The chopper (plus) operation command is “1”, and is output by AND logic 81 with the chopper (plus) operation command of AND logic 79. The chopper (minus) operation command is “0”, and is output by AND logic 82 of the NOT logic 80 and the AND logic 79 chopper (plus) operation command.

  Thus, according to the excitation device of the AC exciter according to the second embodiment, the polarity of the output voltage of the single-phase inverter can be changed to the negative polarity in the chopper operation, so that the chopper operation of the first embodiment can be performed. , The exciting current can be suppressed more rapidly than when the voltage is reduced to “0” (zero) V. Thereby, excitation control can be performed at high speed, and there is an effect of improving the demagnetization characteristics of the main generator in the event of a system fault, load fluctuation, and the like.

  In the above description, the excitation command is described as analog, but the same effect can be obtained even when the signal level is digitized.

Embodiment 3 FIG.
FIG. 12 is a diagram illustrating an operation mode logic circuit of the single-phase inverter of the excitation device of the AC exciter according to the third embodiment. In the first embodiment, each single-phase inverter controls the output voltage. However, in the third embodiment, the input DC voltage of the single-phase inverter is controlled by a converter, whereby the output voltage of the single-phase inverter is controlled. It is something to control. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  As shown in FIG. 12, the operation mode logic circuit of the single-phase inverter includes a d-axis inverter operation mode logic 90, a q-axis inverter operation mode logic 91, and a converter operation mode logic 92 that receive an inverter operation command and a chopper operation command. It consists of

  At startup, an inverter gate fixing command is issued to the d-axis inverter operation mode logic 90 and the q-axis inverter operation mode logic 91 and an inverter DC control command is issued to the converter operation mode logic 92 in accordance with the inverter operation command. The IGBT module operated by the single-phase inverters 31 and 32 is made constant and the switching operation is performed with a fixed output pattern, and the DC voltage output from the converter 41 is controlled, whereby the AC excitation from the single-phase inverters 31 and 32 is performed. The AC excitation output to the d-axis field winding 16 and the q-axis field winding 17 of the machine 9 is controlled.

  In addition, after the start-up is completed and during normal operation, a chopper gate fixing command is issued to the d-axis inverter operation mode logic 90 and the q-axis inverter operation mode logic 91 and a chopper DC control command is issued to the converter operation mode logic 92 according to the chopper operation command. . Thereby, the gate voltage of the IGBT module operated by the single-phase inverters 31 and 32 is kept constant, the chopper operation is performed with a fixed pattern of 100% DC output, and the DC voltage output from the converter 41 is controlled. The DC excitation output from the inverters 31 and 32 to the d-axis field winding 16 and the q-axis field winding 17 of the AC exciter 9 is controlled.

  Thus, according to the excitation device for an AC exciter according to Embodiment 3, the control circuit for the single-phase inverter can be simplified by controlling the DC voltage input of the single-phase inverter with the converter. There is an effect of improving the voltage variation of the two-axis field winding of the AC exciter.

Embodiment 4 FIG.
FIG. 13 is a diagram illustrating an operation mode logic circuit of the single-phase inverter of the excitation device of the AC exciter according to the fourth embodiment. In the third embodiment, after the start-up is completed and during normal operation, the gate of the IGBT module for chopper operation of the single-phase inverter is set to a fixed pattern of 100% DC output, and the DC voltage input of the single-phase inverter is controlled by the converter. In the fourth embodiment, the polarity of the voltage output of the single-phase inverter is switched by switching the IGBT module that performs the chopper operation. Since other configurations are the same as those in the third embodiment, description thereof is omitted.

  As shown in FIG. 13, the operation mode logic circuit of the single-phase inverter includes an d-axis inverter operation mode logic 90 that receives an inverter operation command, a chopper (plus) operation command, and a chopper (minus) operation command, and a q-axis inverter operation. The mode logic 91, the converter operation mode logic 92, and the OR logic 88 connected to the converter operation mode logic 92 are configured.

Since the operation mode logic circuit of the single-phase inverter at the time of start-up is the same as that of the third embodiment, description thereof is omitted.
After startup is complete and during normal operation, a chopper (plus) operation command issues a chopper gate fixing command to the d-axis inverter operation mode logic 90 and the q-axis inverter operation mode logic 91, and a chopper DC control command to the converter operation mode logic 92. put out. Thereby, the gate voltage of the IGBT module to be chopper-operated by the single-phase inverters 31 and 32 is kept constant, the chopper operation is performed with a fixed pattern of 100% DC output, and the DC voltage output from the converter 41 is controlled. The DC excitation output from the inverters 31 and 32 to the d-axis field winding 16 and the q-axis field winding 17 of the AC exciter 9 is controlled.

  On the other hand, since a rapid demagnetization of the main generator 2 is required at the time of a system failure, load change, etc., the d-axis inverter operation mode logic 90 and the q-axis inverter operation are performed by a chopper (minus) operation command. A chopper gate fixing command is issued to the mode logic 91, the IGBT module to be operated by the chopper is switched, and a chopper DC control command is issued to the converter operation mode logic 92. As a result, the polarity of the voltage output of the single-phase inverters 31 and 32 can be changed from positive to negative by switching the IGBT modules that are operated by the single-phase inverters 31 and 32 (see FIGS. 6 and 8). . Thereby, a negative voltage can be applied to the d-axis field winding 16 and the q-axis field winding 17, and the main generator 2 can be rapidly demagnetized.

  As described above, according to the excitation device for an AC exciter according to the fourth embodiment, the polarity of the voltage output of the single-phase inverter can be changed to the negative polarity in the chopper operation. , The excitation current can be suppressed more rapidly than when it is reduced to “0” (zero) V, and even when the output voltage is controlled by a converter, this enables the excitation control to be performed at a high speed, resulting in a system failure. This has the effect of improving the demagnetization characteristics of the main generator at the time of load fluctuation.

Embodiment 5. FIG.
FIG. 14 is a vector diagram of the d-axis excitation current and the q-axis excitation current in the excitation device of the AC exciter according to Embodiment 5. FIG. 15 is a circuit showing a connection between a single-phase inverter and a d-axis field winding and a q-axis field winding. The difference between the single-phase inverter and the d-axis field winding and the q-axis field winding in the first to fourth embodiments is between the d-axis field winding 16 and the q-axis field winding 17. A contactor S7 for connecting the windings in series, a contactor S8 between the d-axis field winding 16 and the output side of the single-phase inverter 31, and a q-axis field winding 17 and a single-phase inverter. The contactor S9 is provided between the 32 output sides. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  As shown in FIG. 14, the excitation current of the AC exciter 9 is a vector composition of the excitation current flowing through the d-axis field winding 16 and the excitation current flowing through the q-axis field winding 17. As an AC voltage, the d-axis and q-axis have a phase of 90 °, and when the d-axis excitation current vector is 1.0 and the q-axis excitation current vector is 1.0, the combined vector is √2. It will have a phase difference of 45 ° in size.

  In the first to fourth embodiments after the start-up is completed and during normal operation, DC excitation of the d-axis field winding 16 and the q-axis field winding 17 is performed by the two single-phase inverters 31 and 32. In this case, the contactor S7 is turned off, the contactor S8 is turned on, and the contactor S9 is turned on.

  During normal operation after completion of startup, a DC current having the same value is normally supplied to the d-axis field winding 16 and the q-axis field winding 17 as the excitation current, but either the single-phase inverter 31 or 32 is supplied. In the case of failure, the gate of the IGBT element of the single-phase inverter 31 or 32 is turned off, the corresponding contactor S8 or contactor S9 is turned off, and the single-phase inverter 31 or 32 is connected to the d-axis field winding 16 or By disconnecting from the q-axis field winding 17 and turning on the contactor S7, disconnection of the failed single-phase inverter and series connection with the other field winding are performed. As a result, even when one of the single-phase inverters fails, power can be supplied to the d-axis field winding 16 and the q-axis field winding 17 and the operation can be continued.

  Furthermore, by increasing the current of the normal single-phase inverter by √2 times, the voltage of the main generator 2 can be set to the original voltage value, and normal operation can be continued.

  As described above, according to the excitation device for an AC exciter according to the fifth embodiment, when one of the single-phase inverters of the excitation device fails due to the circuit configuration in which the two field windings are connected in series. In this case, it is possible to supply power to the field winding from the other single-phase inverter, which has the effect of improving the reliability of the excitation device.

Embodiment 6 FIG.
FIG. 16 is a schematic circuit configuration diagram illustrating an entire gas turbine power generation system using an AC exciter including the excitation device according to the sixth embodiment. The difference from the excitation device in the first embodiment shown in FIG. 1 is that, as shown in FIG. 2, the single-phase inverters 31 and 32 have a DC capacitor 34 connected in series between the switching element and the converter 41 in parallel. , 35 is provided, the excitation device 30 of the sixth embodiment is provided with an electric double layer capacitor 67 capable of storing a large amount of charge between the single-phase inverters 31, 32 and the converter 41. This is the point. Other configurations are the same as those in the first embodiment, and thus description thereof is omitted.

  Due to the provision of the large-capacitance capacitor 67, with respect to the voltage drop or power loss due to an accident of the power system of the excitation power source 73, in the conventional circuit, the excitation lost in 3 ms to 10 ms, An excitation device 30 that can be excited with the same voltage for 100 milliseconds to several seconds can be obtained. This also eliminates the need to connect the PMG 40 to the main generator 2, shortening the axial length of the rotating shaft 45, and reducing the inertia (GD2) of the rotating shaft 45 during startup.

  As described above, according to the excitation device for an AC exciter according to the sixth embodiment, a large amount of capacitor is provided on the input side of the single-phase inverter. There is an effect that the field winding can be excited with the voltage as it is. In addition, there is an effect that the PMG is not required and the apparatus can be downsized by reducing the axial length of the rotating shaft.

  In the above-described embodiment, the case where an electric double layer capacitor is used as a large-capacity capacitor has been described. However, other types of capacitors may be used.

Embodiment 7 FIG.
FIG. 17 is a control block circuit diagram illustrating a control system using an AC exciter including the excitation device according to the seventh embodiment. In the first to sixth embodiments, the circuit operation of the single-phase inverter has been described. In the seventh embodiment, the entire control system using the AC exciter 9 is shown.

  In the control block circuit diagram shown in FIG. 17, current sensors 111 and 112 for detecting the currents of the d-axis field winding 16 and the q-axis field winding 17 and the voltage detector for detecting the voltage of the armature winding 22 are used. VT 113, voltage converter 114, voltage / frequency (V / F) ratio converter 115, slip ring 117 for detecting the voltage of field winding 21, voltage converter 116, adder / subtractor 105, 106, 108, 110, and 124 are provided.

  The control PI amplifiers 103, 104, 107, 109, 121 adjust characteristics such as stability and responsiveness of a control loop having a proportional (P) + integral (I) function.

  As control loops, a current control loop including control PI amplifiers 103 and 104 and gate generation circuits 101 and 102, a field voltage control loop including control PI amplifier 107, an armature voltage control PI amplifier 109, A synchronous machine armature voltage control loop constituted by a control switch 122 or a voltage / frequency (V / F) ratio control loop constituted by a control PI amplifier 121 of a voltage / frequency (V / F) ratio and a control switch 123; Built in. Normally, at the initial stage of startup, the constant field voltage control by the field voltage control loop or the constant V / F ratio control by the voltage / frequency (V / F) ratio control loop is performed. ) Generator voltage constant control is performed by an armature voltage control loop.

  Thus, according to the excitation device for an AC exciter according to the seventh embodiment, at the time of start-up, the output frequency of the single-phase inverter connected to the field winding of the AC exciter is constant, and the single-phase inverter By controlling the output voltage, that is, the voltage or current of each winding of the AC exciter, the field voltage, armature voltage / frequency or armature voltage of the AC exciter is controlled. Control can get. For this reason, there is an effect that a stable operation that does not depend on the temperature or invariability of each winding is possible.

Embodiment 8 FIG.
FIG. 18 is a diagram illustrating the relationship between the rotational speed of the AC exciter and the excitation frequency in an AC exciter including the excitation device according to the eighth embodiment.

At the time of start-up, the rotational speed of the AC exciter 9 which is a synchronous machine is ωr ′ (pu value where the rated rotational speed is 1 pu), and the excitation frequency by the single-phase inverters 31 and 32 is ωexc ′ (the rated rotational speed is 1 pu). (pu value), when the excitation direction is reversed to the rotation direction, a voltage of (ωexc ′ + ωr ′) times is induced in the armature winding 11 of the AC exciter 9. Here, since the loss of the AC exciter 9 increases as the excitation frequency increases, the excitation frequency ωexc ′ by the single-phase inverters 31 and 32 increases as the rotational frequency ωr ′ of the AC exciter 9 increases as shown in FIG. It is possible to reduce the loss by reducing it according to the above.
When ωexc ′ = ω0 ′ (rated rotational speed) −ωr ′ (rotational speed), the excitation frequency automatically becomes direct current. Therefore, there is an effect of suppressing the fluctuation at the time of switching the control from startup to normal.

  As described above, according to the excitation device for an AC exciter according to the eighth embodiment, the output frequency of the single-phase inverter connected to each field winding of the AC exciter is decreased in accordance with the increase in the rotational speed of the AC exciter. By controlling the output voltage of the single-phase inverter, that is, the voltage or current of each winding of the AC exciter in order to keep the field voltage, armature voltage / frequency or armature voltage of the AC exciter constant. There are effects of reducing loss and improving control accuracy.

Embodiment 9 FIG.
FIG. 19 is a diagram illustrating the operation of the single-phase inverter in the DC excitation operation of the excitation device according to the ninth embodiment, and FIG. 20 is the operation of the single-phase inverter in the DC excitation operation of the excitation device according to the ninth embodiment. It is a figure which shows a logic circuit.

  FIG. 20 shows a logic circuit of the chopper operation of the positive side switching element and the chopper operation of the negative side switching element of the single phase inverter. This logic circuit is composed of NOT logic 84 and AND logics 85 and 86. The chopper operation command (chopper (plus) operation command) to the positive side switching element is output by the AND logic 85 of the chopper operation command and the positive side selection command, and the chopper operation command (chopper (minus)) to the negative side switching device. Operation command) is output by AND logic 86 of the chopper operation command and the NOT logic 84 of the positive side selection command.

  In the first and second embodiments, as shown in FIG. 6, when the chopper operation operation of the single-phase inverters 31 and 32 is performed, the switching element 55 of the positive-side IGBT module 51 of the DC capacitor is switched for the chopper operation. As described above, in the ninth embodiment, during the chopper operation of the single-phase inverters 31 and 32, as shown in FIG. 19, the positive-side IGBT module 51 that performs the chopper operation every time the main generator 2 is turned on or off. The switching element 55 and the switching element 58 of the negative-side IGBT module 54 are alternately switched. Although FIG. 19 shows the case where two IGBT modules are switched, the four IGBT modules may be switched in order, and the concentration of use of specific switching elements is eased by leveling the energization time of the four switching elements. Thus, when the switching element is attached to the heat sink, it is possible to prevent the silicone grease used for improving the thermal conductivity from being dried, and to increase the maintenance cycle.

  As described above, according to the exciter for an AC exciter according to the ninth embodiment, during the chopper operation operation of the single-phase inverter, the operation is performed by periodically switching the positive-side and negative-side IGBT modules to be chopper-operated. The energization time of the switching elements to be leveled can be leveled, the temperature rise of the switching elements can be prevented, and the maintenance cycle can be lengthened.

  In the above embodiment, an IGBT element is used as a switching element used in a single-phase inverter. However, a module including elements such as a self-extinguishing transistor, GTO, and GCT may be used.

  Also, within the scope of the present invention, the embodiments can be freely combined, or the embodiments can be appropriately modified or omitted.

  Moreover, in the figure, the same code | symbol shows the same or an equivalent part.

    DESCRIPTION OF SYMBOLS 1 Gas turbine power generation system, 2 Main generators, 3, 30 Exciter, 4 Rotor, 9 AC exciter, 11 Armature winding, 12 Rotary rectifier, 16 d axis field winding, 17 q axis field winding Wire, 21 field winding, 22 armature winding, 23 variable speed inverter, 24 system interconnection transformer, 27 gas turbine, 28 rotor, 31, 32 single phase inverter, 34, 35 DC capacitor, 41 converter, 45 Rotating shaft, 67 condenser, 71 power supply in the center, 72 system power supply, 73 excitation power supply, S1 starter contactor, S2 breaker, S5 starter contactor, S6 normal contactor, 51-54 IGBT module, S7-S9 contactor.

Claims (8)

A single-phase inverter configured to supply current to each of the field windings of the synchronous machine, which is an AC exciter having two-axis field windings, and includes a plurality of switching elements ;
A converter that converts alternating current into direct current and supplies direct-current power to the single-phase inverter ,
In the case of AC excitation, the single-phase inverter is operated as an inverter, and in the case of DC excitation, the single-phase inverter is operated as a chopper, and excitation power is supplied to the generator by the synchronous machine. Exciter for the machine. Prior Symbol DC excitation, by switching the switching element to the chopper operation of the single-phase inverters, the excitation of the AC exciter according to claim 1, characterized in that to change the polarity of the output voltage of the single-phase inverter apparatus. Prior Symbol AC excitation and the direct current excitation, the voltage control switching operation of the single-phase inverters remain constant, by controlling the DC voltage output from the previous SL converter, controlling the output voltage of the single-phase inverter The excitation device for an AC exciter according to claim 1. Prior Symbol DC excitation, by switching the switching element to the chopper operation of the single-phase inverters, the excitation of the AC exciter according to claim 3, characterized in that to change the polarity of the output voltage of the single-phase inverter apparatus.   5. The single-phase inverter according to claim 1, wherein, in the DC excitation, when a malfunction occurs in one of the two single-phase inverters, the defective single-phase inverter is disconnected. Exciter for AC exciter. In the AC excitation, the output voltage or current is controlled while the output frequency of the single-phase inverter is constant, so that the field voltage of the synchronous machine, the voltage of the armature of the synchronous machine, or the voltage / frequency ratio is constant. The excitation device for an AC exciter according to any one of claims 1 to 5 , wherein the excitation device is maintained. In the AC excitation, the output frequency of the single-phase inverter is decreased in accordance with the increase in the rotational speed of the synchronous machine, and the output voltage or current is controlled, whereby the field voltage of the synchronous machine and the electric machine of the synchronous machine are controlled. exciter AC exciter according to any one of claims 1 5, characterized in that to maintain the voltage or the voltage / frequency ratio of the child constant.   In the DC excitation, the switching element to be chopper-operated is alternately switched between the switching element on the positive side of the DC voltage and the switching element on the negative side, and the use frequency of the switching element is leveled. The excitation device for an AC exciter according to claim 2 or 4.