JP3834481B2 - Cogeneration system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cogeneration system, and more particularly to a configuration of a rotor of a generator provided in the cogeneration system, and a configuration of an inverter that adjusts generated power from the generator.
[0002]
[Prior art]
In recent years, a commercial power system of an external commercial power source and a generator power system of a generator are connected to a power transmission system to a power consuming device (load) to cover the power demand of the power consuming device (load) and generate power as a result of power generation. Cogeneration systems that recover exhaust heat generated by a machine and perform heat exchange of water using the recovered heat are widely used.
The generated power is controlled to become demand power together with commercial power by an inverter provided inside the cogeneration system. Such a control system is called a grid-connected system because a generated power system and a commercial power system are linked to each other.
[0003]
A gas engine, a diesel engine, or the like is applied to the generator, and an inverter having a capacity corresponding to the output of the generator is provided.
[0004]
[Problems to be solved by the invention]
Since the inverter described above corresponds to the output of the generator, a high-output generator is inevitably required to be equipped with a large inverter, which increases the cost of the cogeneration system.
In view of the above problems, the present invention proposes a technique that enables the provision of an inverter having a smaller capacity than the generator capacity.
[0005]
[Means for Solving the Problems]
The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
That is, as described in claim 1, a power transmission system in which a commercial power system of an external commercial power source and a generator power system of a generator are connected, and the power demand of the power consuming equipment is covered from the power transmission system, A heat generation system that recovers waste heat generated by a generator by a heat recovery device and performs heat exchange of water, wherein the generator includes a plurality of armature windings and outputs from each armature winding. The three-phase AC output is supplied via an inverter having the same number of armature windings as the U-phase-O-phase-W phase of the single-phase commercial power system or the U-phase-V phase of the three-phase commercial power system. -It is connected to the W phase.
[0006]
Further, according to claim 2, a load current detection current transformer is provided in each phase of the single-phase or three-phase commercial power system to which the three-phase AC output is connected, and the load current detection current transformer is provided. The inverter calculates the power value of the commercial power system detected by the control, and the inverter controls the output power of the generated power system to the power consuming device.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
1 is a circuit diagram of a cogeneration system in which a generator is provided with two armature windings, FIG. 2 is a circuit diagram of a cogeneration system in which a generator is provided with a plurality (n) of armature windings, and FIG. FIG. 3 is a circuit diagram of a cogeneration system showing an embodiment in which an inverter output is connected to a three-phase commercial power system.
[0008]
[Configuration of cogeneration system]
First, a cogeneration system 1 according to the present invention will be described with reference to FIG. FIG. 1 shows an embodiment in a single-phase three-wire commercial power system (U-phase, V-phase, W-phase, O-phase (neutral wire)). In the figure, for convenience of explanation, U phase, W phase, and O phase (neutral wire) shall be shown.
The cogeneration system 1 mainly includes a prime mover 2, a generator 3, an exhaust heat recovery facility 4, a control device 5, and inverters 6a and 6b.
[0009]
A radiator fan 7 is provided in the vicinity of the prime mover 2. And the circulating cooling water 8 of the prime mover 2 is heat-exchanged with the return hot water (circulated hot water 9) from a heat consumption apparatus (not shown) in the exhaust heat recovery equipment 4.
The prime mover 2 includes a starter 10, and power is supplied to the starter 10 from a power transmission system U 3 and W 3 (including a generated power system U 2 and W 2) described later via a transformer 11.
[0010]
The generator 3 includes a rotor (not shown) having a field winding excited by a DC power source on a rotary shaft 12 connected to a drive shaft of the prime mover 2, and an armature winding provided in a stator (not shown). The three-phase outputs 30a and 30b are taken out from the wires 20a and 20b. Thus, the configuration of the generator 3 may be a rotating field type in which the armature windings 20a and 20b are provided on the stator side, and in addition, the armature in which the armature windings 20a and 20b rotate. It can be a field type.
[0011]
The three-phase outputs 30a and 30b from the generator 3 are rectified and smoothed by the diodes 21a and 21b and the capacitors 22a and 22b, and are connected to the DC input portions of the inverters 6a and 6b. The generated power systems U2 and W2 are output from the inverters 6a and 6b.
[0012]
The motor 2, the generator 3, the exhaust heat recovery facility 4, and the inverters 6a and 6b, which are the main components of the cogeneration system 1 described above, are controlled by the control device 5. Furthermore, the system of the cogeneration system 1 is configured to be managed by an operation indicator 28 and a remote operation indicator 29 for displaying / changing the operation state of the control device 5.
[0013]
[Configuration of grid connection]
FIG. 1 shows an embodiment in which the system is connected to a single-phase three-wire commercial power system.
A commercial power system U1 (U phase), W1 (W phase), O1 (neutral line) of a single-phase three-wire 200V is drawn from the external commercial power source 40. The generated power systems U2 and W2 from the cogeneration system 1 are connected in parallel to the commercial power systems U1 and W1 (U phase and W phase). The power of the commercial power systems U1, W1, and O1 and the generated power systems U2 and W2 is transmitted to the power consuming devices (loads) 24, 24, and so on through the power transmission systems U3, W3, and O3.
[0014]
The commercial power systems U1 and W1 are provided with load current detecting current transformers (current transformers) CT1 and CT2.
With the load current detection current transformers CT1 and CT2, the power value of the commercial power system U1 and W1 is calculated by one inverter 6a among the plurality of inverters 6a and 6b. The inverter 6a calculates the total output of the inverters 6a, 6b supplied to the power consuming devices 24, 24,... So that the power value of the commercial power system U1, W1 is constant. The output divided by the number (2 in the embodiment of FIG. 1, n in the embodiment of FIG. 2) is calculated.
The plurality of inverters 6a and 6b are communicated by the multi-drop method, and the inverter 6a that calculates the power value of the commercial power system U1 and W1 transmits the output set value to the other inverter 6b. Then, the inverter 6b performs output control so as to match the output set value from the inverter 6a.
[0015]
A specific example of the operation of the cogeneration system 1 performed by the above grid interconnection will be described below.
(1) When the power consumption of the power consuming device increases, the power demand in the power transmission systems U3 and W3 increases, and the amount of power flowing through the commercial power systems U1 and W1 increases accordingly.
And the increase value of the electric energy of the commercial power grids U1 and W1 is calculated by the inverter 6a from the load current detection current transformers CT1 and CT2.
The inverter 6a controls to increase the outputs of the inverters 6a and 6b.
[0016]
(2) When the power consumption of the power consuming device decreases, the power demand in the power transmission systems U3 and W3 decreases, and the amount of power flowing through the commercial power systems U1 and W1 decreases accordingly.
The inverter 6a calculates the decrease value of the electric energy of the commercial power system U1 and W1 from the load current detection current transformers CT1 and CT2.
The inverter 6a controls the inverters 6a and 6b so as to reduce the total output of the inverters 6a and 6b.
[0017]
[Configuration of multiple windings of generator armature]
As shown in FIG. 1, the generator 3 has a configuration in which two armature windings 20a and 20b are provided for one rotor.
Note that the present invention is not limited to this embodiment, and two armature windings 20a and 20b may be formed in one stator, and one each of the two armature windings 20a and 20b. A rotor may be configured.
Moreover, in the illustration of the armature windings 20a and 20b shown in FIGS. 1 and 2, the symbol of the generator is used in order to express clearly that it is a power generation unit.
[0018]
With the above configuration, as shown in FIG. 1, the three-phase outputs 30a and 30b are separately taken out from the armature windings 20a and 20b, and the three-phase outputs 30a and 30b are respectively connected to the diodes 21a and 21b and the capacitor. It is rectified and smoothed by 22a and 22b and connected to the DC input section of the inverters 6a and 6b. Then, the outputs from the inverters 6a and 6b are integrated to form one generated power system U2 and W2 as the entire cogeneration system 1.
[0019]
FIG. 2 shows an example in which the above configuration is simplified and the number of armature windings is n (plural).
In this example, n (plural) armature windings 20a, 20b,... Are provided on the rotating shaft, and the three-phase output 30a is provided so as to correspond to the respective armature windings 20a, 20b,. , 30b, diodes 21a, 21b, capacitors 22a, 22b, and inverters 6a, 6b,.
In addition, about the detail of the structure in the generator 3, it is the same as that of the example at the time of comprising the said two armature winding.
[0020]
[Effects of using multiple windings for the generator armature]
In the embodiment shown in FIG. 1, since the armature windings 20a and 20b are configured in two, the total value of the power generated by both the armature windings 20a and 20b is the value of the generated power system U2 and W2. Output. That is, the output of each of the armature windings 20a and 20b is half (1/2) the output of the case where the generator 3 is constituted by one armature winding.
[0021]
Correspondingly, the amount of electric power (capacity) supported by the inverters 6a and 6b only needs to correspond to the output of each armature winding 20a and 20b. Compared to the capacity of the inverter, it may be half (1/2). That is, it is possible to apply (equipment) to the inverters 6a and 6b that are smaller, less costly, and capable of stable output of small electric power than the inverter provided with a single armature winding. It can be done.
[0022]
Furthermore, if one of the two inverters 6b is in a disconnected state, only the output of the inverter 6a is obtained, so that the power with a half (1/2) capacity compared to the case of a single inverter. (Low power) output is possible. In other words, even when the power consumption of the load is small (a very small amount), the excess power is not output, and the reverse power flow problem does not occur.
[0023]
In the embodiment shown in FIG. 2, the output of each armature winding 20 a, 20 b... Is 1 / n compared to the case where the generator 3 is constituted by one armature winding. The inverters 6a, 6b,... Can be applied with a 1 / n capacity compared to the case of a single armature winding, and output a smaller amount of power (1 / n). Is possible.
[0024]
[Design of cogeneration system specifications]
By selecting the number of armature windings 20, 20..., It is possible to design the cogeneration system 1 that has the above-described effects and supports power generation in a wide range from low output to high output.
For example, the larger the number of armature windings 20..., The smaller the power capacity managed by the inverters 6, 6. It will be possible. However, in selecting the number, it goes without saying that the complexity and cost due to multiple parts (multiple configurations) are taken into consideration.
In addition, the specification of the minimum output and maximum output of the generator can be changed depending on the number of armature windings 20, 20..., So if each component of the cogeneration system is unified, Since it is only necessary to select the number of each component according to the output specifications, it is possible for the manufacturer to greatly reduce costs in terms of production and stock of each component, as well as for customers. It is possible to provide a cogeneration system with specifications that meet the demands of customers.
[0025]
[Example of connecting inverter output to a three-phase commercial power system]
FIG. 3 shows an embodiment in which inverter outputs U2, V2, and W2 are connected to a three-phase commercial power system U1, V1, and W1, and power is supplied to three-phase loads 50, 50, and so on.
In this embodiment, three-phase inverter outputs U2, V2, and W2 are output from the inverters 6a and 6b, and connected to the U-phase, V-phase, and W-phase of the three-phase commercial power system U1, V1, and W1.
Further, the calculation of the power consumption of the loads 50, 50,... Is performed from the load current detection current transformers CT1, CT2, CT3 provided in the three-phase commercial power systems U1, V1, W1, respectively, by inverters 6a, 6b. It is done by taking in.
As described above, the cogeneration system of the present invention can be applied not only to the above-described single-phase commercial power system but also to a three-phase commercial power system.
[0026]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained. That is, as in claim 1, a power transmission system in which a commercial power system of an external commercial power supply and a power generation power system of a generator are connected, covers the demand power of power consuming equipment from the power transmission system, and accompanies power generation A cogeneration system that recovers exhaust heat generated by a generator by an exhaust heat recovery device and performs heat exchange of water, wherein the generator includes a plurality of armature windings and is output from each armature winding The three-phase AC output is supplied to the U-phase-O-phase-W phase of the single-phase commercial power system or the U-phase-V-phase-W phase of the three-phase commercial power system through the inverters provided in the same number as the armature windings. For example, when the number of armature windings is n (two or more natural numbers), the output of each armature winding constitutes a generator with one armature winding. Compared to the case, the output is 1 / n. In the inverter to which the output is input, a 1 / n capacity capacitor can be applied as compared with the case where the armature winding is configured by one, and thus the cost can be reduced.
[0027]
Further, according to claim 2, a load current detection current transformer is provided in each phase of the single-phase or three-phase commercial power system to which the three-phase AC output is connected, and the load current detection current transformer is provided. The inverter calculates the power value of the commercial power system detected by the inverter, and the inverter controls the output power of the generated power system to the power consuming equipment. Therefore, a small amount of power (1 / n) is generated by the small capacity inverter. It becomes possible to output stably, and it becomes possible to prevent the reverse power flow to a commercial power system.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a cogeneration system in which a generator includes two armature windings.
FIG. 2 is a circuit diagram of a cogeneration system in which a generator is provided with a plurality (n) of armature windings.
FIG. 3 is a circuit diagram of a cogeneration system showing an embodiment in which an inverter output is connected to a three-phase commercial power system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cogeneration system 2 Engine 3 Generator 4 Waste heat recovery equipment 6a, 6b Inverter 20a, 20b Armature winding 30a, 30b Three-phase output 40 External commercial power supply

Claims (2)

A power transmission system connecting the commercial power system of the external commercial power supply and the generator power system of the generator is configured to cover the demand power of the power consuming equipment from the power transmission system, and exhaust heat generated by the generator accompanying power generation is exhausted. A cogeneration system in which heat is recovered by a heat recovery device and water is exchanged. The generator includes a plurality of armature windings, and a three-phase alternating current output from each armature winding is an armature Cogeneration system connected to U phase-O phase-W phase of single-phase commercial power system or U phase-V phase-W phase of three-phase commercial power system through inverters equipped with the same number of windings . Provide a load current detection current transformer in each phase of the single-phase or three-phase commercial power system to which the three-phase AC output is connected, and the power value of the commercial power system detected by the load current detection current transformer The cogeneration system according to claim 1, wherein the inverter calculates the output power, and the inverter controls the output power of the power generation system to the power consuming device.

Images