JP2012085468A - Power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately absorb output fluctuations of a photovoltaic power generation apparatus and prevent reductions in power generation efficiency by increasing responsiveness to the output fluctuations of the photovoltaic power generation apparatus.SOLUTION: A power generation system includes: a secondary excited induction generator 5 having a stator 5b having a primary winding connected to a power system 3 and a rotor 5a having a secondary winding; an engine GE for driving the rotor 5a; a first power converter 6 having an AC side connected to the primary winding; a second power converter 7 having an AC side connected to the secondary winding; a power storage device 8 connected to a DC section 9 connecting a DC side of the first power converter 6 and a DC side of the second power converter 7; and control means 10 for performing engine output control of controlling the operation of the engine to increase/decrease an engine output and performing charge/discharge control of controlling the operation of the first power converter 6 to charge/discharge the power storage device 8 in accordance with primary winding side power of the secondary excited induction generator 5.

Description

  The present invention provides a power generation system in which a solar power generator is connected to a power system to which a power load is connected via a solar power converter, and the power generated by the solar power generator can be supplied to the power load. About.

  In the power generation system as described above, for example, as shown in FIG. 3, the solar power generation device PV is connected to the power system 3 via the DC / DC converter 1 and the solar power generation power conversion device 2. The DC power generated by the solar power generation device PV is converted into AC power by the solar power generation power conversion device 2 and is supplied to the power load 4 freely.

Recently, due to increasing environmental awareness, the introduction of systems using solar power generation as described above has been progressing, and in the future, a large amount of solar power generation devices may be promoted from the viewpoint of reducing CO2 emissions. There is sex. Since the amount of power generated by the solar power generation device is affected by the amount of sunlight, it greatly changes due to changes in weather. Therefore, when a large amount of photovoltaic power generation devices are introduced at the end of the power system, it is necessary to provide a power supply device for absorbing output fluctuations of the photovoltaic power generation devices.
On the other hand, in recent years, introduction of an engine cogeneration system using a gas engine using natural gas as a fuel has been promoted from the viewpoint of environment and economy. Therefore, as shown by the dotted line in FIG. 3, it is considered that the engine cogeneration system EC is combined with the system using solar power generation to absorb the output fluctuation of the solar power generation apparatus by the engine cogeneration system EC. It is done.

As an engine cogeneration system, a system using a synchronous generator that drives a synchronous generator by an engine is known. In the system using this synchronous generator, in order to output a constant frequency (50 [Hz] or 60 [Hz]) by the synchronous generator, the rotational speed of the engine is restricted to the constant rotational speed, and the output is When it is reduced from the rating, the power generation efficiency is greatly reduced.
Therefore, as an engine cogeneration system, in order to change the output while preventing a decrease in power generation efficiency, it is considered to use a system using a secondary excitation induction generator that drives the secondary excitation induction generator with the engine. (For example, refer to Patent Document 1). In the system described in Patent Document 1, even when the output is reduced from the rated value by controlling the frequency of the alternating current supplied to the secondary winding of the secondary excitation induction generator, a constant frequency (50 [Hz] or 60 [Hz]), while being output, the engine can be operated at a good rotational speed from the viewpoint of efficiency, and a reduction in power generation efficiency can be prevented.

JP 2006-101633 A

  As described above, when the engine cogeneration system is combined with a system using solar power generation, the engine output in the engine cogeneration system is controlled so that the output fluctuation is absorbed when the output of the solar power generation apparatus fluctuates. Will do. However, it takes a certain amount of time until the engine output can actually be changed after the engine operation is controlled to change the engine output to a desired engine output. That is, there is a response delay. Therefore, the response of the output change of the engine cogeneration system is poor with respect to the output fluctuation of the solar power generation apparatus that fluctuates in a relatively short time, and it becomes difficult to effectively absorb the output fluctuation of the solar power generation apparatus. It was.

  The present invention has been made paying attention to such a point, and its purpose is to improve the response to the output fluctuation of the solar power generation apparatus, appropriately absorb the output fluctuation of the solar power generation apparatus, and generate power. The point is to provide a power generation system capable of preventing a decrease in efficiency.

In order to achieve this object, a characteristic configuration of a power generation system according to the present invention is that a solar power generation device is connected to a power system to which a power load is connected via a solar power conversion device, and the solar power generation device In the power generation system that can freely supply the power generated by the power load,
A secondary excitation induction generator having a stator having a primary winding connected to the electric power system and a rotor having a secondary winding, an engine for driving the rotor, and an AC side on the primary winding Connect the connected first power converter, the second power converter whose AC side is connected to the secondary winding, the DC side of the first power converter and the DC side of the second power converter A power storage device connected to the direct current section, and engine output control for controlling the operation of the engine so as to increase or decrease the engine output, and according to the power on the primary winding side in the secondary excitation induction generator And a control means for performing charge / discharge control for controlling the operation of the first power converter so as to charge / discharge the power storage device.

When the output of the solar power generation device fluctuates, the control means performs engine output control and charge / discharge control so as to absorb the output fluctuation of the solar power generation device by increasing / decreasing the engine output and charging / discharging the power storage device. It can be performed.
For example, when the output of the photovoltaic power generation device fluctuates to the lower side, when the control means performs engine output control, the engine output is increased so as to absorb the fluctuation to the lower side. The power on the primary winding side in the secondary excitation induction generator increases with the increase. However, since it takes time until the engine output actually increases, the increase in the power on the primary winding side in the secondary excitation induction generator is delayed with respect to the decrease in the output of the photovoltaic power generation apparatus. Therefore, by performing charge / discharge control by the control means, secondary excitation induction is performed in order to discharge the power storage device so as to compensate for the short time output fluctuation that cannot be absorbed by the engine output control among the output fluctuation of the photovoltaic power generation device. The operation of the first power converter can be controlled to increase the power supplied to the primary winding side of the generator.

  In this way, for a short time output fluctuation that cannot be absorbed by the engine output control while absorbing the output fluctuation of the photovoltaic power generation device due to the increase or decrease of the engine output by the engine output control, the charging / discharging control of the power storage device is charged. It can be compensated by electric discharge. Therefore, it is possible to improve the responsiveness to the output fluctuation of the solar power generation apparatus, appropriately absorb the output fluctuation of the solar power generation apparatus, and prevent the power generation efficiency from decreasing.

  The power generation system according to the present invention can be additionally provided with respect to an existing system in which a system using solar power generation that can freely supply power generated by the solar power generation apparatus to an electric power load is already introduced. Therefore, it is possible to provide a useful power generation system that can appropriately absorb the output fluctuation of the photovoltaic power generation apparatus and effectively prevent a decrease in power generation efficiency while effectively utilizing the existing system.

  A further characteristic configuration of the power generation system according to the present invention is that, in the engine output control, the control means increases or decreases the engine output according to the difference between the power between the power system and the power load and the target power. In the charge and discharge control, based on the difference between the power and the target power between the power system and the power load, and the power on the primary winding side in the secondary excitation induction generator, The charge / discharge amount of the power storage device is controlled such that the power between the power system and the power load becomes the target power.

  When the output fluctuation of the photovoltaic power generator occurs, the power between the power system and the power load fluctuates, so there is a difference between the power and the target power according to the magnitude of the output fluctuation of the photovoltaic power generator. Will occur. Therefore, according to this characteristic configuration, in the engine output control, the control means controls the increase / decrease amount of the engine output in accordance with the difference between the power between the power system and the power load and the target power. The engine output can be increased or decreased to appropriately absorb the output fluctuation of the device. When the engine output increases or decreases, the power on the primary winding side of the secondary excitation induction generator also fluctuates, so the power fluctuation on the primary winding side of the secondary excitation induction generator is the actual increase or decrease of the engine output. It becomes the size according to. Therefore, the difference between the power and the target power between the power system and the power load and the power fluctuation on the primary winding side in the secondary excitation induction generator is a short time that cannot be absorbed by the engine output control. A difference corresponding to the magnitude of the output fluctuation occurs. Therefore, according to this characteristic configuration, in charge / discharge control, based on the difference between the power and the target power between the power system and the power load, and the power on the primary winding side in the secondary excitation induction generator, By controlling the charge / discharge amount of the power storage device so that the power between the power system and the power load becomes the target power, the power storage device can be appropriately compensated for short-term output fluctuations that cannot be absorbed by engine output control. Charge / discharge amount can be controlled.

  According to a further characteristic configuration of the power generation system according to the present invention, the control means controls the operation of the engine so as to increase the engine output when the power storage amount of the power storage device is less than a lower limit set amount. A charging operation for controlling the operation of the first power converter so as to charge the power storage device with the power on the primary winding side in the secondary excitation induction generator can be executed, and a power storage amount of the power storage device is an upper limit When the amount exceeds the set amount, the operation of the engine is controlled so as to reduce the engine output, and the electric power discharged from the power storage device is supplied to the primary winding side of the secondary excitation induction generator. Further, the discharge operation for controlling the operation of the first power converter can be executed.

According to this characteristic configuration, when the storage amount of the power storage device is less than the lower limit set amount, the control unit can perform the charging operation to charge the power storage device. Since the power charged in the power storage device can be used by the control means to perform charge / discharge control, the power stored in the power storage device can be appropriately charged while effectively using the charged power. Can do.
When the power storage amount of the power storage device is equal to or greater than the upper limit set amount, the control unit can perform a discharge operation to discharge from the power storage device. In the discharge operation, the power discharged from the power storage device is supplied to the primary winding side of the secondary excitation induction generator, so that the power discharged from the power storage device can be supplied to the power load, Discharge can be performed. When power discharged from the power storage device is supplied to the primary winding side of the secondary excitation induction generator, the power on the primary winding side of the secondary excitation induction generator increases by that amount, but the engine output Therefore, it is possible to prevent the electric power on the primary winding side in the secondary excitation induction generator from increasing more than necessary.

The figure which shows schematic structure of the electric power generation system which concerns on this invention The graph which shows the change of an output when the output fluctuation of a solar power generation device arises in the electric power generation system concerning the present invention. The figure which shows schematic structure of the conventional power generation system

An embodiment of a power generation system according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, in the power generation system 100, each of a plurality of photovoltaic power generation devices PV is connected to a power system 3 via a DC / DC converter 1 and a photovoltaic power conversion device 2. . The power generation system 100 is configured to convert DC power generated by the photovoltaic power generation device PV into AC power by the photovoltaic power conversion device 2 and supply it to the power load 4 that consumes power. . FIG. 1 shows an example in which two photovoltaic power generation devices PV are provided and three power loads 4 are provided. As the electric power load 4, various electric power devices that consume electric power can be applied. For example, there are an indoor unit, an outdoor unit, an electric lamp, and the like included in the air conditioning equipment.

  In such a power generation system, the output of the photovoltaic power generator PV varies due to changes in the weather, so it is necessary to absorb the output variation. Therefore, in the power generation system according to the present invention, an engine cogeneration system EC is provided to absorb the output fluctuation of the solar power generation device PV.

  The engine cogeneration system EC includes a secondary excitation induction generator (double-feed winding induction generator) 5, a gas engine GE, a first power converter 6, a second power converter 7, and a power storage device 8. And is configured. The engine cogeneration system EC controls the operation of the gas engine GE so as to increase or decrease the engine output of the gas engine GE, and also controls the operation of the first power converter 6 and the second power converter 7. (Corresponding to control means) is provided.

  The secondary excitation induction generator 5 generates power (three-phase AC power) of the same frequency (for example, 50 [Hz] or 60 [Hz]) as the power system (commercial power system) 3 and uses the power as power. It is configured to be freely supplied to the load 4 and the power system 3. The secondary excitation induction generator 5 includes a stator 5b (stator) having a primary winding (not shown) and a rotor 5a (rotor) having a secondary winding (not shown). . The primary winding included in the stator 5 b is connected to the power system 3 and the power load 4. On the other hand, the secondary winding included in the rotor 5 a is connected to the power system 3 and the power load 4 via the second power converter 7, the DC unit 9, and the first power converter 6.

  Regarding the secondary excitation induction generator 5, the primary winding side included in the stator 5b is referred to as "primary side of the secondary excitation induction generator", and the secondary winding side included in the rotor 5a is referred to as "secondary excitation induction generator". Secondary side ". Therefore, the frequency of the power (voltage, current) on the primary side of the secondary excitation induction generator 5 is the frequency of the power supplied to the power load 4 and the power system 3.

  The gas engine GE is mechanically connected to the rotor 5a of the secondary excitation induction generator 5, and rotationally drives the rotor 5a. The output shaft of the gas engine GE is directly connected so as to rotate integrally with the rotor 5a, and the rotational speed of the gas engine GE and the rotational speed of the rotor 5a are configured to be equal. The gas engine GE is, for example, an engine that uses city gas as fuel, and is provided as a drive source for a cogeneration system that can supply both electric power and heat. Incidentally, it is possible to replace the gas engine GE with an engine using gasoline, light oil, heavy oil or the like as fuel.

  The AC side (the upper side in FIG. 1) of the first power converter 6 is connected to the stator 5b (primary winding) of the secondary excitation induction generator 5, and to the power system 3 and the power load 4. ing. The direct current side (the lower side in FIG. 1) of the first power converter 6 is connected to the direct current unit 9. The AC side (lower side in FIG. 1) of the second power converter 7 is connected to the rotor 5a (secondary winding) of the secondary excitation induction generator 5. The DC side of the second power converter 7 (upper side in FIG. 1) is connected to the DC unit 9. Each of the first power converter 6 and the second power converter 7 converts the DC power on the DC side into AC power (reverse conversion) and supplies it to the AC side, and the AC power on the AC side. It is configured to be able to perform both of the function as a converter that converts (forward-converts) into DC power and supplies it to the DC side. The first power converter 6 and the second power converter 7 are configured to include a plurality of (for example, six) switching elements, for example.

  The DC unit 9 is a part that connects the DC side of the first power converter 6 and the DC side of the second power converter 7. A power storage device 8 is connected to the DC unit 9. The power storage device 8 is configured by, for example, a storage battery, an electric double layer capacitor, or the like, and can supply and discharge power to the DC unit 9 and can be charged by receiving supply of power from the DC unit 9. Composed.

  Although not shown in FIG. 1, the power generation system 100 includes a switch that connects and disconnects the primary winding included in the stator 5 b and the power system 3, and outputs a predetermined frequency component. A filter, a transformer, or the like to be removed is also provided at a desired location as necessary.

  The engine cogeneration system EC is a system having a high degree of freedom with respect to the frequency (voltage, current frequency) of the generated power. Since this point is a well-known technique as described in Patent Document 1, a detailed description thereof will be omitted and will be briefly described.

The frequency of the generated power of the engine cogeneration system EC (primary side voltage induced on the primary side of the secondary excitation induction generator 5) is f1, the rotation frequency of the rotor 5a is f0, and the secondary winding of the rotor 5a. If the frequency of the alternating current (alternating voltage) supplied to the secondary winding to excite the wire is f2, “f1 = f0 + f2”.
Here, the rotational frequency f0 of the rotor 5a is obtained from “f0 = m × n / 120” where the rotational speed of the rotor 5a is m [rpm] and the number of magnetic poles of the secondary excitation induction generator 5 is n. .

  For example, when the rotation speed of the rotor 5a is 1100 [rpm] and the number of magnetic poles of the secondary excitation induction generator 5 is “6”, the rotation frequency f0 of the rotor 5a is 55 [Hz]. Therefore, in this case, if the control device 10 controls the second power converter 7 and supplies an AC current (AC voltage) having a frequency of 5 [Hz] to the secondary winding (f2 = 5 [Hz]). AC power having a frequency of 60 [Hz] can be obtained. Conversely, if the control device 10 controls the second power converter 12 to extract an AC current (AC voltage) having a frequency of 5 [Hz] from the secondary winding (f2 = −5 [Hz]), AC power with a frequency of 50 [Hz] can be obtained.

  As described above, even when the gas engine GE is operated at a constant rotational speed that is favorable in terms of efficiency, and the rotational speed of the rotor 5a is constant, the alternating current supplied to the secondary winding of the rotor 5a is reduced. The frequency f1 of the generated power can be changed by changing the frequency f2 (as described above, a negative value is obtained when an alternating current is extracted from the secondary winding). As a result, the output of the engine cogeneration system EC can be changed while the gas engine GE can be operated under efficient operating conditions. Therefore, the power generation efficiency can be maintained at a high level even in the partial load operation in which the output of the engine cogeneration system EC is reduced below the rating.

  In the power generation system 100 according to the present invention, an engine cogeneration system EC is provided to absorb the output fluctuation of the solar power generation device PV. The control device 10 that controls the operation of the engine cogeneration system EC performs engine output control for controlling the operation of the gas engine GE so as to increase or decrease the engine output, and the primary of the stator 5b in the secondary excitation induction generator 5 It is configured to perform an output fluctuation absorption operation in which charge / discharge control is performed to control the operation of the first power converter 6 so as to charge / discharge the power storage device 8 according to the power on the winding side. In order to perform the output fluctuation absorption operation, the control device 10 includes an engine output control unit 11 that performs engine output control and a charge / discharge control unit 12 that performs charge / discharge control.

  In the engine output control in the output fluctuation absorbing operation, the engine output control unit 11 determines the engine output according to the difference between the power between the power system 3 and the power load 4 and the target power (for example, zero or any constant value). The amount of increase / decrease is controlled. A first current detection point D1 between the power system 3 and the power load 4 is provided with a first current sensor 13 for detecting the magnitude and direction of the current at the first current detection point D1. The engine output control unit 11 obtains a target difference between the current detected by the current sensor 13 (power between the power system 3 and the power load 4) and the target current (target power), and absorbs the target difference. Therefore, the operation of the gas engine GE is controlled so as to increase or decrease the engine output by the determined increase / decrease amount.

If the output of the photovoltaic power generator PV fluctuates to the lower side while the current at the first current detection point D1 is the target current, the power supplied from the power system 3 increases, so the first current detection point D1 Current increases from the target current. Therefore, when the current detected by the first current sensor 13 is larger than the target current, the engine output control unit 11 determines the engine corresponding to the target difference between the current detected by the first current sensor 13 and the target current. The operation of the gas engine GE is controlled so as to obtain an increase in output and increase the engine output by the obtained increase.
On the other hand, the output of the photovoltaic power generator PV fluctuates to the increasing side while the current at the first current detection point D1 is the target current, and the current detected by the first current sensor 13 is higher than the target current. When it becomes smaller, the engine output control unit 11 obtains a reduction amount of the engine output according to the target difference between the current detected by the first current sensor 13 and the target current, and the engine output is calculated by the obtained reduction amount. The operation of the gas engine GE is controlled in order to lower the engine.

  In the charge / discharge control in the output fluctuation absorption operation, the charge / discharge control unit 12 determines the difference between the power between the power system 3 and the power load 4 and the target power, and the stator 5b in the secondary excitation induction generator 5. Based on the power on the primary winding side, the charge / discharge amount of the power storage device 8 is controlled so that the power between the power system 3 and the power load 4 becomes the target power. At the second current detection point D2 on the primary winding side of the stator 5b in the secondary excitation induction generator 5, a second current sensor 14 for detecting the magnitude and direction of the current is provided. The charge / discharge control unit 12 detects the current detected by the first current sensor 13 based on the difference between the current detected by the first current sensor 13 and the target current and the current detected by the second current sensor 14. The charge / discharge amount of the power storage device 8 is determined so that the current becomes the target current, and the operation of the first power converter 6 is controlled to charge / discharge from the power storage device 8 by the determined charge / discharge amount. .

When the current detected by the first current sensor 13 is larger than the target current, the charge / discharge control unit 12 calculates the target difference between the current detected by the first current sensor 13 and the target current, and the determination The amount of discharge of the power storage device 8 for compensating for the difference between the target difference and the current detected by the second current sensor 14 is obtained, and the stator 5b in the secondary excitation induction generator 5 is obtained from the power storage device 8 by the calculated amount of discharge. First power conversion so as to function as an inverter that converts the DC power of the DC section 9 into AC power and supplies it to the primary winding of the stator 5b in the secondary excitation induction generator 5 The operation of the machine 6 is controlled.
Conversely, when the current detected by the first current sensor 13 is smaller than the target current, the charge / discharge control unit 12 obtains the target difference between the current detected by the first current sensor 13 and the target current, In order to obtain the charge amount of the power storage device 8 for absorbing the difference between the obtained target difference and the current detected by the second current sensor 14, secondary excitation is performed so that the power storage device 8 is charged by the obtained charge amount. The operation of the first power converter 6 is controlled so as to function as a converter that converts the AC power of the primary winding of the stator 5 b in the induction generator 5 to DC power and supplies it to the DC unit 9.

  Fig.2 (a) has shown the change of the output when the output of the solar power generation device PV fluctuates in the power generation system 100 according to the present invention. P1 indicated by a solid line in the figure is a power generation output of the solar power generation device PV, P2 indicated by a thick dotted line in the figure is an output command value of an engine output commanded to the gas engine GE, and P3 indicated by a thin dotted line in the figure Is the actual engine output of the gas engine GE, and P4 indicated by the alternate long and short dash line in the figure indicates the output of the power storage device 8.

  When the power generation output P1 of the solar power generation device PV fluctuates to the lower side, the engine output control unit 11 performs the engine output control so that the output command value P2 is increased so as to increase the engine output by the fluctuation amount to the lower side. Commanded to gas engine GE. However, since it takes some time until the engine output is actually increased, the actual engine output P3 increases with a delay with respect to the decrease in the power generation output P1. Therefore, the charge / discharge control unit 12 performs charge / discharge control to increase the output P4 of the power storage device 8 so as to compensate for the delay of the engine output P3 with respect to the decrease in the power generation output P1. Therefore, the increase in engine output P3 and the increase in output P4 of power storage device 8 can absorb the fluctuation in power generation output P1 toward the decrease side. As described above, by performing the engine output control and the charge / discharge control, after the fluctuation amount to the decrease side of the power generation output P1 is absorbed, only the increase of the engine output by the engine output control leads to the decrease side of the power generation output P1. Output fluctuations can be absorbed. Therefore, the control device 10 controls the operation of the first power converter 6 so that the charge / discharge amount of the power storage device 8 becomes zero, and decreases the output P4 of the power storage device 8 as the engine output P3 increases. ing.

  FIG.2 (b) has shown the change of the output when the output of the solar power generation device PV is fluctuate | varied to the increase side in the electric power generation system 100 which concerns on this invention. P1 indicated by a solid line in the figure is a power generation output of the solar power generation device PV, P2 indicated by a thick dotted line in the figure is an output command value of an engine output commanded to the gas engine GE, and P3 indicated by a thin dotted line in the figure Is the actual engine output of the gas engine GE, and P4 indicated by the alternate long and short dash line in the figure indicates the output of the power storage device 8.

  When the power generation output P1 of the solar power generation device PV fluctuates to the increase side, the engine output control unit 11 performs engine output control, so that the output command value P2 is set so as to decrease the engine output by the variation to the increase side. Commanded to gas engine GE. However, since it takes a certain amount of time for the engine output to actually decrease, the actual engine output P3 decreases with a delay with respect to the increase in the power generation output P1. Therefore, the charge / discharge control unit 12 performs charge / discharge control to reduce the output P4 of the power storage device 8 so as to compensate for the delay of the engine output P3 with respect to the increase of the power generation output P1. Therefore, the fluctuation of the power generation output P1 to the increase side can be absorbed by the decrease of the engine output P3 and the decrease of the output P4 of the power storage device 8. Here, FIG. 2B shows a state where the power storage device 8 is charged because the output P4 of the power storage device 8 is on the negative side. As described above, by performing the engine output control and the charge / discharge control, after the fluctuation to the increase side of the power generation output P1 is absorbed, the power generation output P1 is increased only by the decrease of the engine output by the engine output control. Output fluctuations can be absorbed. Therefore, the control device 10 controls the operation of the first power converter 6 so that the charge / discharge amount of the power storage device 8 becomes zero, and increases the output P4 of the power storage device 8 as the engine output P3 decreases. ing.

  In this way, the engine output control unit 11 performs engine output control so that the charge / discharge control unit 12 performs charge / discharge control while controlling the engine output so as to absorb the output fluctuation of the photovoltaic power generator PV. By performing the above, the power storage device 8 can be charged / discharged so as to absorb a short time output fluctuation of the solar power generation device PV that cannot be absorbed by the engine output control. Therefore, the engine cogeneration system EC can change the output with high responsiveness to the output fluctuation of the solar power generation device PV, and can appropriately absorb the output fluctuation of the solar power generation device PV.

  In addition to the output fluctuation absorption operation for controlling the operation of the engine cogeneration system EC so as to absorb the output fluctuation amount of the solar power generation device PV, the control device 10 is charged in the power storage device 8 and charged. A discharge operation for discharging from the power storage device 8 can be executed.

  When the amount of power stored in power storage device 8 is less than the lower limit set amount, control device 10 performs a charging operation. In this charging operation, the control device 10 controls the operation of the gas engine GE so as to increase the engine output, and the power on the primary winding side of the stator 5b in the secondary excitation induction generator 5 is supplied to the power storage device 8. It is comprised so that the action | operation of the 1st power converter 6 may be controlled so that it may charge. In the charging operation, since the engine output is increased, the power on the primary winding side of the stator 5b in the secondary excitation induction generator 5 is larger than the power for absorbing the output fluctuation of the photovoltaic power generator PV. Thus, surplus power exists. Therefore, the control device 10 converts the AC power of the primary winding of the stator 5b in the secondary excitation induction generator 5 into DC power and supplies it to the DC unit 9 in order to charge the power storage device 8 with the surplus power. The operation of the first power converter 6 is controlled so as to function as a converter.

  When the power storage amount of power storage device 8 is equal to or greater than the upper limit set amount, control device 10 performs a discharge operation. In this discharge operation, the control device 10 controls the operation of the gas engine GE so as to reduce the engine output, and the electric power discharged from the power storage device 8 is used as the primary winding of the stator 5b in the secondary excitation induction generator 5. The operation of the first power converter 6 is controlled to be supplied to the line side. In the discharge operation, since the engine output is reduced, the power on the primary winding side of the stator 5b in the secondary excitation induction generator 5 is smaller than the power for absorbing the output fluctuation of the photovoltaic power generator PV. Thus, there will be insufficient power. Therefore, the control device 10 converts the DC power of the DC unit 9 into AC power and supplies it to the primary winding of the stator 5b in the secondary excitation induction generator 5 in order to discharge the insufficient power from the power storage device 8. The operation of the first power converter 6 is controlled so as to function as an inverter.

  As described above, the engine cogeneration system EC can start the system in a state where it is connected to the electric power system 3, and the control device 10 can operate the gas engine even when it is not connected to the electric power system 3. The engine cogeneration system EC is activated (independently activated) by using the electric power supplied from the power storage device 8 by driving the GE and controlling the operations of the first power converter 6 and the second power converter 7. It is configured to be possible. Therefore, even when a power failure or the like occurs in the power system 3, the control device 10 drives the gas engine GE in the state where the connection with the power system 3 is released by a switch or the like not shown, and the first The engine cogeneration system EC can be activated using the power supplied from the power storage device 8 by controlling the operation of the power converter 6 and the second power converter 7. Thereby, although illustration is abbreviate | omitted, even when a power failure etc. arise in the electric power grid | system 3 when an electric power load is connected to the primary winding side in the stator 5b of the secondary excitation induction generator 5, The engine cogeneration system EC can be activated and the output of the engine cogeneration system EC can be supplied to a power load connected to the primary winding side of the stator 5b of the secondary excitation induction generator 5.

[Another embodiment]
(1) In the above embodiment, when the control device 10 performs engine output control and charge / discharge control, current is detected as power using the current sensors 13 and 14, but instead of this configuration, voltage is used as power. Can also be detected.

(2) In the above embodiment, the control device 10 includes the engine output control unit 11 that performs engine output control and the charge / discharge control unit 12 that performs charge / discharge control. It can also comprise so that both control and charging / discharging control may be performed.

  In the present invention, a solar power generation device is connected to a power system to which a power load is connected via a solar power converter, and the power generated by the solar power generation device can be freely supplied to the power load. It is possible to adapt to various power generation systems that can improve the responsiveness to the output fluctuation of the solar power generation apparatus, appropriately absorb the output fluctuation of the solar power generation apparatus, and prevent a decrease in power generation efficiency.

DESCRIPTION OF SYMBOLS 3 Electric power system 4 Electric power load 5 Secondary excitation induction generator 5a Rotor 5b Stator 6 1st power converter 7 2nd power converter 8 Electric power storage apparatus 9 DC part 10 Control apparatus (control means)
GE gas engine (engine)
PV solar power generator

Claims (3)

A solar power generation device is connected to a power system to which a power load is connected via a solar power conversion device, and a power generation system that can freely supply power generated by the solar power generation device to the power load,
A secondary excitation induction generator having a stator having a primary winding connected to the electric power system and a rotor having a secondary winding, an engine for driving the rotor, and an AC side on the primary winding Connect the connected first power converter, the second power converter whose AC side is connected to the secondary winding, the DC side of the first power converter and the DC side of the second power converter A power storage device connected to the direct current section, and engine output control for controlling the operation of the engine so as to increase or decrease the engine output, and according to the power on the primary winding side in the secondary excitation induction generator A power generation system provided with control means for performing charge / discharge control for controlling the operation of the first power converter so as to charge / discharge the power storage device.   The control means controls an increase / decrease amount of the engine output according to a difference between a power and a target power between the power system and the power load in the engine output control, and in the charge / discharge control, the power system The power between the power system and the power load is based on the difference between the power between the power load and the target power and the power on the primary winding side in the secondary excitation induction generator. The power generation system according to claim 1, wherein a charge / discharge amount of the power storage device is controlled to be the target power.   The control means controls the operation of the engine so as to increase the engine output when the storage amount of the power storage device is less than a lower limit set amount, and the primary winding side in the secondary excitation induction generator If the power storage device can be charged to control the operation of the first power converter so as to charge the power storage device, and the power storage amount of the power storage device is greater than or equal to the upper limit set amount, the engine output is reduced. And controlling the operation of the first power converter so as to supply the electric power discharged from the power storage device to the primary winding side of the secondary excitation induction generator The power generation system according to claim 1, wherein the power generation system is configured to be able to execute an operation.

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