JPH11187698A - Generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply generated power of a general-purpose AC generator satisfactorily, while expensive system linkage protective device and synchronous closing device are not used and utilization factor of a dynamoelectric prime mover is not lowered, regardless of the specification of a load and furthermore, to drive a constant voltage and constant frequency general load while energy saving is practiced by utilizing frequency decline. SOLUTION: A dynamoelectric prime mover 1 is driven at a constant revolution, and a constant voltage and constant frequency power is generated by a synchronous generator 2. The generated power is supplied to a general load 5 and all the excessive power is supplied to a heat transfer machine load 12 preferentially over a power supplied from a commercial power supply 6 through a reverse-blocking type converter unit 7. Insufficient power is made up for with the power from the commercial power supply 6. When a necessary power of the general load 5 is abruptly increased, a converter unit 3 is controlled and the power from the commercial power supply 6 is immediately supplied to the heat transfer machine load 12 to avoid the frequency decrease of the heat transfer machine load 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration system and the like, in which an AC generator is linked to a rotary engine such as a gas engine, a diesel engine, a gas turbine, or a Stirling engine, and is obtained by the AC generator. The present invention relates to a power generation system configured to be able to supply generated power and power from a commercial power supply.

[0002]

2. Description of the Related Art As a power generation system of this type, a commercial power system and an AC generator driven by a rotary motor are connected to an AC system or separated from the commercial power system and a load is generated by the AC generator. Direct driving, so-called independent operation, was common.

[0003]

By the way, in general, the load often includes a device such as a fan or a motor which can reduce the driving power by lowering the rotation speed by frequency control. In order to reduce the number of rotations of such a device, in the case of independent operation, it is possible by reducing the number of rotations of the rotary type motor itself, but in the case of system interconnection, the number of rotations is reduced through an inverter. Must be lowered.

[0004] However, when the AC generator is used to drive the coupled load and attempt to reduce the driving power by changing the rotational speed (frequency change), the rotational speed of the rotary type prime mover is controlled by lowering the rotational speed. Not only does the capacity of the rotary prime mover decrease in proportion to it, but also the power of the rotary prime mover decreases significantly, and the utilization rate of the rotary prime mover decreases. Further, in that case, there is a disadvantage that a load requiring a constant frequency cannot be driven.

[0005] Further, in the case where the AC generator is connected to the system to change the rotation speed of the load by inverter driving, an expensive system connection protection device is required, and a synchronous generator is used as the AC generator. In such a case, a synchronization input device is required to match the phases of the two powers, and there is a disadvantage that the entire system becomes expensive.

The present invention has been made in view of such circumstances, and the power generation system according to the first aspect of the present invention does not use an expensive system interconnection protection device or a synchronous input device, and can reduce the load. Regardless of the specifications, while using a general-purpose AC generator, it is possible to supply the generated power satisfactorily without reducing the utilization rate of the rotary prime mover, and to save energy by using the frequency reduction ,
An object of the present invention is to drive a general load having a constant voltage and a constant frequency, and a power generation system according to the second aspect of the present invention can easily and inexpensively achieve the object of the first aspect of the invention. The purpose is to.

[0007]

According to a first aspect of the present invention, there is provided a variable frequency power generation system comprising: an AC power supply; a DC power supply; A converter unit for converting power into DC power and a reverse blocking converter unit for converting AC power to DC power and preventing backflow are connected in parallel, and on the AC side of the converter unit, linked to a rotary prime mover. An AC power generator is connected, a commercial power supply is connected to the AC side of the reverse blocking converter unit, and a device that can reduce the driving power by reducing the rotation speed is connected to the AC side of the inverter unit. A general load, which is driven at a constant voltage and a constant frequency and has a required power smaller than a rated value of the AC power generator, is connected between the device and the converter section, Power detection means for detecting the power generation amount of the power generation device, and detecting the power amount supplied to the DC side of the converter unit when the power generation amount detected by the power detection means is smaller than the rated value of the AC power generation device. Control means is provided for controlling the converter so that the amount of generated power increases until the rated value is reached, and when the amount of generated power is larger than the rated value, the detected amount of generated power decreases until the detected value falls below the rated value.

As the rotary prime mover, a gas engine, a diesel engine, a steam turbine, or the like is used. In addition, as a device that can reduce the driving power by reducing the rotation speed, a fan, a chilled / hot water pump, a compressor, an instrumentation air compressor, and the like that constitute an air conditioning system can be applied. In addition, as a general load driven at a constant voltage and a constant frequency, lighting equipment, a heater, and the like can be applied.

According to a second aspect of the present invention, there is provided a power generation system, comprising: a converter section for converting AC power to DC power on a DC side of an inverter section for converting DC power to AC power; And a reverse-blocking converter unit for converting AC power to DC power and blocking backflow in parallel, and connecting a synchronous generator interlocked to a rotary prime mover to the AC side of the converter unit, Connect a commercial power supply to the AC side of the reverse blocking converter,
On the AC side of the inverter unit, a device capable of reducing the drive power by reducing the rotation speed is connected, and between the synchronous generator and the converter unit, the synchronous power generator is driven at a constant voltage and constant frequency and the required power is controlled by the synchronous power generation. A general load smaller than the rated value of the converter is connected, and the synchronous generator is provided so that the DC side terminal voltage of the converter section is higher than the DC side terminal voltage of the reverse blocking converter section. A control means is provided for adjusting the set voltage of the automatic voltage control device and controlling the amount of power supplied to the DC side of the converter section.

[0010]

According to the configuration of the power generation system according to the first aspect of the invention, the AC power generated by the AC power generator is converted into DC power by the converter, and then converted into AC power of a variable frequency by the inverter. The load is supplied to the load in preference to the power from the commercial power supply supplied through the blocking converter unit, and the shortfall is covered by the power from the commercial power supply.

The AC power generated by the AC power generator is converted into DC power by the converter, converted into AC power by the inverter, and then supplied to equipment capable of reducing the driving power by lowering the rotation speed. The rotation speed of the equipment can be controlled regardless of the rotation speed of the type prime mover.

[0012] Further, in the case where the AC power generated by the AC power generator is converted into DC power by the converter section, the DC power is combined with DC power from a commercial power supply supplied through the reverse blocking type converter section to be combined in the AC state. As described above, it is not necessary to synchronize for phase matching, and it is also unnecessary to provide a system interconnection protection device for protecting a commercial power system using a commercial power supply.

[0013] Further, the rotary type prime mover is driven at a constant rotation speed, whereby the alternating-current power generator obtains the power generated at a constant voltage and constant frequency and supplies it to a general load. To the load via the inverter section. Here, when the power required by a general load suddenly increases due to turning on the power and the engine is likely to be overloaded, the converter section is controlled to stop the current flowing from the AC generator to the DC section. , To prevent overload,
The power from the commercial power supply is immediately supplied to the load through the reverse blocking converter section, so that a frequency drop at the load can be prevented.

Further, according to the configuration of the power generation system according to the second aspect, the automatic voltage control device is controlled so that the AC voltage on the synchronous generator side is higher than the AC voltage on the commercial power supply side. The DC voltage after the rectification by the inverter is made higher than the DC voltage after the rectification by the reverse blocking converter unit, and the electric power that is the rated value of the synchronous generator can be preferentially supplied to the load.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of a power generation system according to the present invention.
FIG. 1 is a schematic configuration diagram illustrating an embodiment, in which a synchronous generator 2 as a power generation device is interlockedly connected to a rotary prime mover (gas engine) 1.

The AC side of a converter section 3 for converting AC power into DC power is connected to the synchronous generator 2 via a first power output line 4. A general load 5 driven at a constant voltage and a constant frequency is connected to the first power output line 4. A reverse blocking converter unit 7 for converting AC power into DC power and preventing backflow is connected to a commercial power supply 6 via a second power output line 8.

The DC side of the converter section 3 and the reverse blocking type converter section 7 are respectively connected to the DC side of the inverter section 9 for converting DC power into AC power via the power line 10 and the first and second branch power lines 10a and 10b. Connected. A smoothing capacitor 11 is connected to the power line 10.

The inverter unit 9 is provided with a heat transfer device load as a device capable of reducing the driving power by lowering the rotation speed, such as a pump motor for driving a chilled water pump or a fan motor for driving a fan, which constitutes an air conditioning system. 1
2 are connected via a third power output line 13.

The rated value of the synchronous generator 2 is smaller than the minimum power required for the entire system, which is the sum of the power required by the general load 5 and the heat transfer equipment load 12, and the minimum power. It is set to generate a near electric energy. That is, a general-purpose synchronous generator 2 having a rated value close to the required minimum electric energy is selected.

The first power output line 4 is provided with power detection means 14 for detecting the power on the AC side of the converter section 3. The power detecting means 14 includes a current transducer 14
a and a voltage transducer 14b.

The current transducer 14a and the voltage transducer 14b are connected to a controller 15 as control means, and the controller 15 is connected to the converter 3. In the controller 15,
When the power generation amount detected by the power detection means 14 is smaller than the rated value of the synchronous generator 2, the switching control of the converter unit 3 is performed, and the power amount supplied to the DC side of the converter unit 3 is changed to the rated power generation amount. When the value exceeds the rated value, the detected power generation amount decreases until the detected power generation becomes equal to or less than the rated value. Thereby, the synchronous generator 2
, Can be supplied to the heat transfer equipment load 12 in preference to the electric power from the commercial power supply 6.

The power line 10 is provided with a voltmeter 16 for detecting a DC voltage. The voltmeter 16 is connected to the controller 15, and controls the switching of the converter unit 3 when the DC voltage exceeds a set value, thereby achieving synchronization. The power from the generator 2 is prevented from flowing, and the smoothing capacitor 11 is prevented from being damaged due to an increase in voltage.

With the above configuration, as shown in the graph of FIG. 2, even if the power amount P1 required by the general load 5 fluctuates, the entire amount can be covered by the generated power amount P of the synchronous generator 2. it can. Then, the surplus power amount ΔP is supplied to the heat transfer device load 12, and the difference from the power amount P 2 required by the heat transfer device load 12, that is, the insufficient power amount P
3 can be covered by the electric power from the commercial power supply 6 and can cope with a load change in the heat transfer equipment load 12.

According to the first embodiment, the following effects can be obtained. AC power from the commercial power supply 6 is a reverse blocking converter unit 7
, The reverse power flow of the generated power from the synchronous generator 2 to the commercial power source 6 can be prevented without using an expensive system interconnection protection device. The rotary motor 1 can be driven at a high-efficiency rated load to maintain the power generation efficiency of the synchronous generator 2 at a high level, and the entire amount of the generated power can be supplied to the general load 5 and the heat transfer equipment load 12. Further, since the rotation speed is maintained at the rated rotation speed, the performance of the rotary motor 2 does not decrease. In the general load 5, even if the required amount of power suddenly increases at the time of turning on the power or the like, the fact is as follows.
Is detected as a decrease in voltage or frequency and the current flowing from the synchronous generator 2 through the converter unit 3 is reduced or stopped to prevent the overload of the rotary motor 1. At that time, the synchronous generator 2
From the commercial power source 6 to supply the heat transfer device load 12 with the power of the sudden decrease in the power amount supplied to the heat transfer device load 12, so that the required power amount at the general load 5 sharply increases. And the frequency of the heat transfer device load 12 can be prevented from lowering. Since the AC power from the synchronous generator 2 is converted into DC power by the converter section 3 and the AC power from the commercial power supply 6 is converted into DC power by the reverse blocking converter section 7 and merged in a DC state. It is possible to eliminate the need for a synchronous input device as in the case of merging in a state.

FIG. 3 shows a second example of the power generation system according to the present invention.
It is a schematic block diagram showing an Example, and a different point from 1st Example is as follows. That is, the second power output line 8
The current transducer 17 is connected to the controller 15a, and the controller 15a is connected to the automatic voltage control device 2a provided in the synchronous generator 2.

In the controller 15a, while the converter unit 3 and the reverse blocking converter unit 9 (both of which can be constituted by diodes) are always energized, the current values detected by the two current transducers 14a and 17 are compared. The AC voltage input to the converter unit 3 is higher than the AC voltage input to the reverse blocking converter unit 9, that is, the DC terminal voltage of the converter unit 3 is changed to the DC side voltage of the reverse blocking converter unit 9. The set voltage of the automatic voltage control device 2a is automatically controlled so as to be higher than the terminal voltage.

Thus, the DC voltage rectified by the converter unit 3 can be maintained at a higher level than the DC voltage rectified by the reverse blocking converter unit 9, and the electric power from the synchronous generator 2 is supplied from the commercial power supply 6. Heat transfer equipment load 1 prior to electric power
2 is provided. According to the second embodiment, since the automatic voltage control device 2a provided in the synchronous generator 2 is used, there is an advantage that the configuration for priority supply described above can be reduced in cost.

FIG. 4 shows a third embodiment of the power generation system according to the present invention.
It is a schematic block diagram showing an Example, and a different point from 1st Example is as follows. That is, the controller 15 is connected to the reverse blocking converter section 7 instead of the converter section 3 to control switching of the amount of electric power supplied through the reverse blocking converter section 7, and the electric power from the synchronous generator 2 is supplied from the commercial power supply 6. The power is supplied to the heat transfer device load 12 in preference to the power. Other configurations are the same as those of the first embodiment.

In the first, second and third embodiments, the converter unit 3, the reverse blocking converter unit 7, the inverter unit 9 and the smoothing capacitor 11 are composed of a single inverter set 18 (FIG. 1, 3 and 4).

FIG. 5 is a schematic configuration diagram showing an application example of the power generation system according to the present invention. The difference from the first embodiment is as follows. That is, when the blower 19 and the fan 20 having different frequencies during stable driving are used as the heat transfer equipment loads, the individual inverter sets 18
The synchronous generator 2 is connected to the inverter set 18 and the commercial power supply 6 is connected to each inverter set 18.

The synchronous generator 2 and the two inverter sets 1
Lighting equipment 21 driven at a constant voltage and a constant frequency is connected to a first power output line portion 4a that connects the branch points to 8 and 18. Although not shown, the first power output line portion 4
a, and the first power output line portions 4b, 4b connecting the ends of the first power output line portions 4a and the converter portions 3 of the respective inverter sets 18 are provided with the same power detection means as described above. As in the first embodiment, the power generated by the synchronous generator 2 can be supplied to the heat transfer equipment load 12 in preference to the power from the commercial power supply 6.

According to this application example, when the frequency of the blower 19 and the fan 20 are individually controlled, it is possible to avoid the influence of the fluctuation of the frequency from affecting each other.

In the above embodiment, the synchronous generator 2 is used as the AC generator, but an induction generator may be used. In that case, the converter unit 3 may be configured to be capable of reverse flow, and may supply reactive power required by the induction generator.

According to the present invention, for example, a fuel cell, a solar power generation device, or the like may be connected to the power line 10 so as to use DC power obtained by power generation.

In the present invention, the rotary prime mover 1 is not limited to the gas engine as in the above-described embodiment, but may be a diesel engine, a steam turbine, a gas turbine, a Stirling engine, or the like.

[0037]

As is apparent from the above description, according to the power generation system of the first aspect of the present invention, while the power that is the rated value of the AC power generation device is preferentially supplied to the load, the shortage is eliminated. Since the power is supplied from the commercial power supply, an AC power generator having a general-purpose rated value smaller than the load required by the system can be easily selected and used, and the system can be configured at low cost. Also, since the AC power generated by the AC power generator is converted into DC power by the converter unit, and then converted into AC power by the inverter unit and supplied to the load, the driving power can be reduced by lowering the rotational speed of a part of the load. Even if the device is used, regardless of the change in the number of revolutions,
The rotary prime mover can be driven at a constant rotation speed, and regardless of the specifications of the load, the AC power efficiently generated by the AC generator can be satisfactorily supplied without reducing the utilization rate of the rotary prime mover. In addition, a general load having a constant frequency is directly connected to the output line of the AC generator, so that no inverter loss occurs. Also, since the AC power from the commercial power supply is converted to DC power through the reverse blocking converter unit, and then converted to AC power by the inverter unit and supplied to the load,
An expensive system interconnection protection device for preventing reverse power flow from the AC power generator side can be eliminated and the cost is reduced.

Further, after the AC power generated by the AC power generator is converted into DC power by the converter section, it is converted into AC power by the inverter section, and then supplied to a device capable of reducing the driving power by lowering the rotation speed. Since the rotation speed of the equipment can be controlled regardless of the rotation speed of the type prime mover, the drive power of the equipment can be reduced while maintaining the rotation type motor at a high utilization rate, and the amount of power supplied from the commercial power source is reduced as much as possible. It is economical because the consumption can be reduced well.

Further, after the AC power generated by the AC power generator is converted into DC power by the converter section, the DC power is combined with the DC power from the commercial power supply supplied through the reverse blocking type converter section. Such a synchronous input device can be eliminated, and the power generation system can be configured at lower cost.

Further, the rotary type prime mover is driven at a constant rotation speed, thereby generating power of a constant voltage and constant frequency by the AC generator and supplying the generated power to a general load. Even if it increases sharply, the increase can be covered by the generated power, and the accompanying sudden decrease in the amount of power supplied to the equipment can be covered immediately by the power from the commercial power supply. It is possible to satisfactorily supply power to the general load and drive at a constant voltage / constant frequency while preventing a decrease in the frequency of the device due to a rapid increase in the required power amount in the general load with good responsiveness.

According to the power generation system of the second aspect, since the automatic voltage control device provided in the synchronous generator is used, the power supplied from the converter can be controlled at very low cost. The same effect as that of the invention according to the first aspect can be achieved easily and at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a power generation system according to the present invention.

FIG. 2 is a graph showing a change over time in a required power amount.

FIG. 3 is a schematic configuration diagram showing a second embodiment of the power generation system according to the present invention.

FIG. 4 is a schematic configuration diagram showing a third embodiment of the power generation system according to the present invention.

FIG. 5 is a schematic configuration diagram showing an application example of the power generation system according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotary motor (gas engine) 2 ... Synchronous generator as an alternating current generator 2a ... Automatic voltage controller 3 ... Converter part 4 ... 1st electric power output line 5 ... General load 6 ... Commercial power supply 7 ... Reverse blocking type Converter section 9 ... Inverter section 12 ... Heat transfer equipment load 14 ... Power detection means 15, 15a ... Controller as control means 19 ... Blower as equipment 20 ... Fan as equipment 21 ... Lighting equipment as general load

Claims (2)

[Claims] A converter for converting AC power to DC power, and a reverse blocking converter for converting AC power to DC power and preventing a backflow, on a DC side of an inverter for converting DC power to AC power. Are connected in parallel, an AC generator connected to a rotary prime mover is connected to the AC side of the converter section, and a commercial power supply is connected to the AC side of the reverse blocking converter section. On the side, while connecting a device that can reduce the driving power by reducing the rotation speed, between the AC generator and the converter unit, driven at a constant voltage and constant frequency and the required power is higher than the rated value of the AC generator. Power detection means for detecting a power generation amount of the AC power generation device, and a power generation amount detected by the power detection means. When the value is smaller than the rated value, the amount of power supplied to the DC side of the converter unit is increased until the detected power generation reaches the rated value, and when the detected power generation amount is larger than the rated value,
Control means for controlling the converter unit so that the detected power generation amount decreases to a rated value or less. 2. A converter for converting AC power to DC power, and a reverse blocking converter for converting AC power to DC power and preventing backflow, on a DC side of an inverter for converting DC power to AC power. Are connected in parallel with each other, a synchronous generator connected to a rotary prime mover is connected to the AC side of the converter section, and a commercial power supply is connected to the AC side of the reverse blocking converter section. Side, a device that can reduce the driving power by reducing the rotation speed is connected, and between the synchronous generator and the converter unit, is driven at a constant voltage and constant frequency and the required power is higher than the rated value of the synchronous generator. Is connected so that the DC side terminal voltage of the converter unit is higher than the DC side terminal voltage of the reverse blocking converter unit. A power generation system comprising: a control unit that adjusts a set voltage of an automatic voltage control device provided in a generator to control an amount of power supplied to a DC side of the converter unit.