阅读说明：本技术 压缩空气储能发电装置及压缩空气储能发电方法 (Compressed air energy storage power generation device and compressed air energy storage power generation method ) 是由 佐藤隆 中道亮 于 2019-10-10 设计创作，主要内容包括：压缩空气储能发电装置(1)具备：多台压缩膨胀兼用机(14),具有利用电力制造压缩空气的功能及利用压缩空气进行发电的功能；蓄压部(10),与多台压缩膨胀兼用机(14)流体地连接,将压缩空气储存；以及控制装置(16),当产生了将充放电切换的充放电指令值时,将驱动中的第1压缩膨胀兼用机(14)停止,并且将停止中的第2压缩膨胀兼用机(14)驱动。(A compressed air energy-storage power generation device (1) is provided with: a plurality of compressors and expanders (14) having a function of producing compressed air from electricity and a function of generating electricity from the compressed air; a pressure storage unit (10) that is fluidly connected to the plurality of compressors (14) and stores compressed air; and a control device (16) which stops the 1 st compression-expansion dual-purpose machine (14) during driving and drives the 2 nd compression-expansion dual-purpose machine (14) during stopping when a charge-discharge command value for switching charge and discharge is generated.)

1. A compressed air energy storage generating set is characterized in that,

the disclosed device is provided with:

a plurality of compressors/expanders having a function of producing compressed air by using electric power and a function of generating electric power by using the compressed air;

a pressure storage unit which is fluidly connected to the plurality of compression/expansion machines and stores the compressed air; and

when a charge/discharge command value for switching charge/discharge is generated, the control device stops the 1 st compression/expansion dual-purpose machine being driven and drives the 2 nd compression/expansion dual-purpose machine being stopped.

2. The compressed air energy-storing power generation device of claim 1,

the charge/discharge command value is a predicted value or a planned value of charge/discharge.

3. A compressed air energy-storing electricity generating apparatus according to claim 1 or 2,

the control device sets fatigue amounts for the plurality of the combined compression and expansion machines, and drives the 2 nd combined compression and expansion machine in order from the one with the smaller fatigue amount when the charge/discharge command value for switching charge/discharge is generated.

4. The compressed air energy-storing power generation device of claim 3,

the fatigue amount is represented by a function based on the number of times of switching between charge and discharge.

5. A compressed air energy storage generating set is characterized in that,

the disclosed device is provided with:

a plurality of compression/expansion dual-purpose machines each having an electric power generation dual-purpose machine;

a pressure storage unit which is fluidly connected to the plurality of compression/expansion machines and stores compressed air; and

and a control device for stopping the currently operating compressor-expander and driving the currently stopped compressor-expander when a charge/discharge command value for switching charge/discharge is generated.

6. The compressed air energy-storing power generation device of claim 5,

the plurality of the compression-expansion dual-purpose machines are at least 3 compression-expansion dual-purpose machines;

the control device sets fatigue amounts for the plurality of the combined compression and expansion machines, and drives the 2 nd combined compression and expansion machine in order from the one with the smaller fatigue amount when the charge/discharge command value for switching charge/discharge is generated.

7. The compressed air energy-storing power generation device of claim 6,

the fatigue amount is represented by a function based on the number of times of switching between charge and discharge.

8. A compressed air energy storage power generation method is characterized in that,

the method comprises the following steps:

preparing a compressed air energy-storing power generation device provided with a plurality of combined compression and expansion machines having a function of producing compressed air by using electric power and a function of generating power by using the compressed air, and a pressure accumulating portion which is fluidly connected to the plurality of combined compression and expansion machines and stores the compressed air;

when a charge/discharge command value for switching charge/discharge is generated, the 1 st compression/expansion dual-purpose machine that is being driven is stopped, and the 2 nd compression/expansion dual-purpose machine that is being stopped is driven.

Technical Field

The invention relates to a compressed air energy storage power generation device and a compressed air energy storage power generation method.

Background

Power generation using renewable energy such as wind power or solar energy varies in amount according to weather. In order to smooth fluctuations in power generation amount, an energy storage device may be provided in a power plant using renewable energy, such as a wind power plant or a solar power plant. As an example of such an Energy Storage device, a Compressed Air Energy Storage (CAES) power generation device is known. The CAES power generation apparatus is an apparatus that produces and stores compressed air using electric power and generates power at appropriate times using a stored compressed air using a turbo generator or the like. The compressor/expander that includes the electric motor/generator may be a multi-stage compressor/expander that performs multi-stage compression or expansion using 1 electric motor/generator.

Patent document 1 describes an Adiabatic Compressed Air Energy Storage (ACAES) power generation device that recovers heat from Compressed Air before storing the Compressed Air and reheats the stored Compressed Air when supplying the Compressed Air to a turbine generator. The ACAES power generator recovers the heat of compression and uses it for power generation, and therefore has higher power generation efficiency than a general CAES power generator. Hereinafter, the ACAES power generator and the CAES power generator are simply referred to as CAES power generators without distinction.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-509529.

Disclosure of Invention

Problems to be solved by the invention

In the CAES power generation apparatus, a compressor/expander that can use a compressor driven by a motor as an expander driven by a generator is sometimes used from the viewpoint of installation space and the like. The compression/expansion dual-purpose machine has a motor/generator dual-purpose machine having both functions of a motor and a generator. Therefore, the compressor/expander can switch between the compression function (charging function of the CAES power generation device) and the expansion function (discharging function of the CAES power generation device) according to the situation. That is, charge and discharge can be switched.

In the CAES power generation apparatus, since temperature control and the like are involved in switching between charge and discharge, smooth switching cannot be performed in many compression/expansion machines. That is, a standby time for switching charge and discharge occurs. The standby time is preferably as short as possible because the operation efficiency of the CAES power generation apparatus is reduced. In the CAES power generation apparatus of patent document 1, a compressor/expander is not used, and there is no mention of a standby time involved in switching between charge and discharge. Therefore, in order to apply the compressor-expander to the CAES power generation apparatus of patent document 1 to achieve efficient operation, a method of shortening the standby time is required.

The invention aims to shorten the standby time of charge and discharge switching of a compression and expansion dual-purpose machine in a compressed air energy storage power generation device and a compressed air energy storage power generation method using the compression and expansion dual-purpose machine.

Means for solving the problems

The invention according to claim 1 provides a compressed air energy-storage power generation device including: a plurality of compressors/expanders having a function of producing compressed air by using electric power and a function of generating electric power by using the compressed air; a pressure storage unit which is fluidly connected to the plurality of compression/expansion machines and stores the compressed air; and a control device for stopping the 1 st compression-expansion dual-purpose machine during driving and driving the 2 nd compression-expansion dual-purpose machine during stopping when a charge-discharge command value for switching charge and discharge is generated.

According to this configuration, the standby time associated with the switching of the charge and discharge can be shortened or omitted by controlling the plurality of compression/expansion dual-purpose machines. The compressed air energy storage power generation device produces compressed air from electric power (input power), stores the compressed air in the pressure storage unit, and generates required electric power (required power) at appropriate times from the stored compressed air. If the balance between the input power and the required power changes with the passage of time, switching between charge and discharge may be required. In the above configuration, when the charge/discharge command value for switching charge/discharge is generated, the 1 st combined compression/expansion machine during driving is not used by switching charge/discharge, but the 1 st combined compression/expansion machine during driving is stopped and the 2 nd combined compression/expansion machine during stopping is driven. Since the 1 st compression/expansion dual-purpose machine can be stopped and the 2 nd compression/expansion dual-purpose machine can be started at the same time, the standby time involved in switching between charge and discharge can be omitted. Here, the term "charging" refers to the production of compressed air and the storage of the compressed air in the accumulator by using a compressor and an expander as a compressor. The discharge is a power generation in which the compressor/expander is used as an expander (power generator) and compressed air is taken out from the pressure accumulator. The charge/discharge command value is a command value for specifying a charge amount or a discharge amount for the compressed air energy storage power generation device.

The charge/discharge command value may be a predicted value or a planned value of charge/discharge.

According to this configuration, since control is performed based on the predicted value or planned value of charge and discharge, efficient control with less time delay can be performed. The predicted value or planned value of the charge/discharge may be calculated based on the past data of the same time zone, for example. In addition, when the input power is power generated by renewable energy such as solar energy or wind power, the amount of input power (amount of charge) may be predicted based on meteorological conditions. In the case where the required power is power required by equipment such as a factory, prediction may be made based on the operating time of the equipment such as a factory in the daytime or at night.

The control device may set a fatigue amount for each of the plurality of compressors and expanders, and may drive the compressors and expanders as the 2 nd compressor and expander in order from the one with the smaller fatigue amount when the charge/discharge command value for switching charge/discharge is generated.

With this configuration, the loss of the compression/expansion dual-purpose machine can be made uniform. If a specific compressor-expander is driven in a concentrated manner without making the loss uniform, the specific compressor-expander needs to be maintained early, and the maintenance frequency of the CAES power generation apparatus as a whole may increase. Therefore, in order to reduce the frequency of maintenance, it is effective to make the degree of wear uniform. The 1 st and 2 nd compressors and expanders may be 1 compressor and expander, respectively, or a plurality of compressors and expanders may be 1 unit.

The fatigue amount may be expressed as a function of the number of times of switching between charge and discharge.

According to this configuration, the fatigue amount is set based on the number of times of switching between charge and discharge, whereby the degree of wear of the compression/expansion dual-purpose machine can be made more uniform. In particular, the number of times of switching between charge and discharge is a parameter unique to a compressor and an expander that cannot be considered in a normal compressor and expander. Therefore, the loss of the compressor-expander can be accurately equalized.

The 2 nd aspect of the present invention provides a compressed air energy-storing power generation device, including: a plurality of compression/expansion dual-purpose machines each having an electric power generation dual-purpose machine; a pressure storage unit which is fluidly connected to the plurality of compression/expansion machines and stores compressed air; and a control device which stops the currently operating compressor-expander and drives the currently stopped compressor-expander when a charge/discharge command value for switching charge/discharge is generated.

According to this configuration, as described above, the standby time associated with the switching between the charge and the discharge can be shortened or omitted by controlling the plurality of compression/expansion machines.

The plurality of the compression/expansion dual-purpose machines may be at least 3 compression/expansion dual-purpose machines; the control device sets fatigue amounts for the plurality of the combined compression and expansion machines, and drives the 2 nd combined compression and expansion machine in order from the one with the smaller fatigue amount when the charge/discharge command value for switching charge/discharge is generated.

According to this configuration, the loss of the compression-expansion dual-purpose machine can be made uniform as described above.

The fatigue amount may be expressed as a function of the number of times of switching between charge and discharge.

According to this configuration, as described above, by setting the fatigue amount based on the number of times of switching between charge and discharge, the degree of loss of the compression/expansion dual-purpose machine can be made more uniform.

The 3 rd scheme of the invention provides a compressed air energy storage power generation method, which comprises the following steps: preparing a compressed air energy-storing power generation device provided with a plurality of combined compression and expansion machines having a function of producing compressed air by using electric power and a function of generating power by using the compressed air, and a pressure accumulating portion which is fluidly connected to the plurality of combined compression and expansion machines and stores the compressed air; when a charge/discharge command value for switching charge/discharge is generated, the 1 st compression/expansion dual-purpose machine that is being driven is stopped, and the 2 nd compression/expansion dual-purpose machine that is being stopped is driven.

According to this method, as described above, the standby time associated with the switching between the charge and the discharge can be omitted by controlling the plurality of compressors and expanders.

Effects of the invention

According to the present invention, in the compressed air energy-storing power generation apparatus and the compressed air energy-storing power generation method using the combined compressor and expander, the standby time involved in the switching of the charge and discharge can be omitted by controlling the plurality of combined compressor and expander.

Drawings

Fig. 1 is a schematic configuration diagram of a compressed air energy-storing power generation device according to an embodiment of the present invention.

Fig. 2 is a top view of the interior of the 1 st vessel.

FIG. 3 is an interior side view of the 1 st container.

Fig. 4 is a flowchart schematically showing control of the compressed air energy-storage power generation device.

Fig. 5 is a flowchart showing the power generation process.

Fig. 6 is a flowchart showing the charging process.

Detailed Description

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Referring to fig. 1, a Compressed Air Energy Storage (CAES) power generation apparatus 1 and a wind power plant 2 are electrically connected to a system power supply (not shown). Since the amount of power generated by the wind power plant 2 varies depending on weather or the like, the CAES power generation apparatus 1 is provided as an energy storage device for smoothing the varying amount of power to transmit power to or receive power from the grid power supply.

The CAES power generation device 1 includes a1 st container C1 having a charge/discharge function, a2 nd container C2 having a control function, a pressure accumulator 10, and a heat medium tank 12. The 1 st container C1 and the pressure accumulating portion 10 are connected via an air pipe 11. The heating medium tank 12 and the 1 st container C1 and the 2 nd container C2 are connected to each other via a heating medium pipe 13. The 1 st containers C1 are arranged in two rows along the air pipe 11. The 2 nd container C2 was arranged in 1 st row between the 1 st containers C1 in the same direction as the 1 st container C1 in the two rows. However, the arrangement is not particularly limited, and may be appropriately changed according to conditions such as terrain.

Fig. 1 conceptually shows the pressure accumulating portion 10. The pressure accumulator 10 stores compressed air. The form of the pressure storage portion 10 is not particularly limited as long as it can store compressed air, and may be, for example, a steel tank or an underground cavity. The pressure accumulating portion 10 is fluidly connected to a compressor/expander 14 (see fig. 2 and 3) in the 1 st tank C1 via an air pipe 11, as will be described later.

The heat medium tank 12 is disposed between the 1 st vessel C1 and the 2 nd vessel C2. The heat medium tank 12 may be a steel tank, for example. The heat carrier tank 12 stores a heat carrier. The type of the heating medium is not particularly limited, and may be, for example, water, oil, or the like. In the present embodiment, the heat medium flows between the two heat medium tanks 12, the 1 st vessel C1, and the 1 nd vessel C2, and the 1 closed heat medium system is configured by these. Preferably, 1 of the two heat medium tanks 12 stores a high-temperature heat medium, and the other stores a low-temperature heat medium.

The interior of the 1 st container C1 will be described with reference to fig. 2.

In the 1 st container C1, 3 compressors and expanders 14 and 3 heat exchangers 15 are housed. Specifically, 1 heat exchanger 15 is provided for 1 compression/expansion dual-purpose machine 14.

The compressor/expander 14 is a device that switches the direction of air flow by switching the inlet and outlet of air, and that doubles as a compressor driven by an electric motor as an expander driven by a generator. The compressor/expander 14 includes an electric motor/generator 14 a. In the present embodiment, the compression/expansion dual-purpose machine 14 is of a screw type and includes a pair of male and female screw rotors, not shown. The electric/power generation dual-purpose machine 14a is mechanically connected to the screw rotor. The motor/generator 14a has a function as a motor and a function as a generator, and can be switched to use. By using the electric/power generation dual-purpose machine 14a as an electric motor and rotating the screw rotor (i.e., driving the compressor), air can be compressed. The screw rotor is rotated by using compressed air (that is, the expander is driven by expanding the compressed air), and the combined motor/generator 14a can be used as a generator. Therefore, the combined compressor and expander 14 has a function of compressing air by consuming electric power from the wind power plant 2 and a function of generating electric power by using the compressed air from the pressure storage unit 5. In the present embodiment, the compression/expansion dual-purpose machine 14 may have a structure other than a screw type as long as it is a volume type.

The heat exchanger 15 has a function as a cooler for cooling the compressed air and a function as a heater for heating the compressed air, and can be switched between these functions. The heat exchanger 15 may also be of a common plate type construction, for example. When the heat exchanger 15 functions as a cooler for cooling the compressed air, the combined compression and expansion machine 14 functions as a compressor, and the high-temperature compressed air and the low-temperature heat medium compressed by the combined compression and expansion machine 14 flow into the heat exchanger 15, and the compressed air and the heated heat medium cooled after the heat exchange flow out of the heat exchanger 15. When the heat exchanger 15 functions as a heater for heating the compressed air, the combined compression and expansion machine 14 functions as a generator, and the low-temperature compressed air and the high-temperature heat medium to be supplied to the combined compression and expansion machine 14 flow into the heat exchanger 15, and the compressed air heated after the heat exchange and the cooled heat medium flow out of the heat exchanger 15.

In the 2 nd container C2, a pump for flowing a heat medium, an inverter/converter/brake resistor for changing the rotation speed of the combined compressor and expander 14, a controller 16, and the like are housed. The control device 16 is constructed of hardware such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and software installed therein. The controller 16 receives data on electric power (required electric power) requested from a factory or the like (not shown) and electric power (input electric power) from the wind power plant 2. Specifically, the control device 16 receives a value obtained by subtracting the required electric power from the input electric power as the charge/discharge command value W. The controller 16 determines whether the electric power is excessive or insufficient based on the charge/discharge command value W, and controls the operation of the CAES power generation apparatus 1. That is, based on the determination by the control device 16, switching between charging and discharging and rotational speed control of the combined compression and expansion machine 14 are performed.

The charging is to use the compression/expansion dual-purpose machine 14 as a compressor, to produce compressed air, and to store the compressed air in the pressure accumulator 10. The discharge is a power generation in which the compressor/expander 14 is used as an expander (power generator) and compressed air is taken out from the pressure accumulator 10. The charge/discharge command value W is a command value specifying a charge amount or a discharge amount for the CAES power generation apparatus 1. Based on the charge/discharge command value W, charging is performed when the input power is larger than the required power, and discharging (hereinafter also referred to as power generation) is performed when the required power is larger than the input power.

The operation control of the CAES power generation apparatus 1 according to the present embodiment will be described with reference to fig. 4 to 6.

Referring to fig. 4, if the CAES power generation apparatus 1 starts operating, the counting of time T is started from 0 (step S4-1). Then, it is determined whether or not the charge/discharge command value W is greater than 0 (step S4-2). When the charge/discharge command value W is larger than 0 (YES in step S4-2), the power generation process is executed (step S4-3). When the charge-discharge command value W is 0 or less (NO: step S4-2), the charging process is executed (step S4-4).

The charge/discharge command value W is larger than 0, and indicates that the required power from a factory or the like is larger than the input power from the wind power plant 2. At this time, even if the power is supplied directly from the wind power plant 2 to the factory or the like, the power is not generated enough. The charge/discharge command value W is a value of 0 or less, and indicates that the input power from the wind power plant 2 is larger than the required power from a factory or the like. At this time, even if power is supplied directly from the wind power plant 2 to a factory or the like, the power is excessively supplied, and therefore the excessively large amount is charged.

Referring to fig. 5, in the power generation process, first, the number of the combined compression and expansion machines 14 to be driven by the rated power generator is calculated (step S5-1). In the present embodiment, since the drive control is performed for the 1 st container C1, the number of rated drives is calculated as the number of rated driven 1 st containers C1. That is, the number of cells n of rated driving was calculated using 1 unit of 3 combined compression/expansion machines 14 in the 1 st container C1. Here, if the rated drive output of 1 cell is P, the number of cells n is calculated as the maximum integer n not exceeding the number (n = [ | W |/P ]) obtained by dividing the absolute value of the charge-discharge command value W by the output P.

Next, the fatigue amount FPi of each compressor-expander 14 is calculated (step S5-2). In the present embodiment, since the drive control is performed in accordance with the 1 st container C1 as described above, the fatigue amount FPi is calculated in accordance with the 1 st cell as described above. Thus, if the number of the 1 st containers C1 is N, since all N cells exist, the fatigue amount FPi is calculated as FP1, FP2, … …, FPN.

The fatigue amount FPi is expressed by the following equation (1) as the result of addition of the operation time function fa, the start frequency function fb, and the reversal frequency function fc.

[ numerical formula 1 ]

TCi: integral value of charging side operation output of ith unit

TGi: integral value of power generation side operation output of i-th cell

NCi: cumulative number of charging operations (as number of compressor starts) of ith unit

NGi: cumulative number of times of generator operation (as number of times of starting of generator)

GCi: the number of times of switching charge and discharge of the i-th cell.

The operating time function fa is a function integrating operating times, and includes the integrated values TCi and TGi as parameters. The operating time function fa is always continuously integrated during the continuation of operation. That is, the value is always updated to the latest value while the operation is continued. The operation time function fa may be expressed by the following equation (2) with a1 and a2 being positive constants, for example.

[ numerical formula 2 ]

。

The start frequency function fb is a function of integrating the start frequency, and includes the above-described frequencies NCi and NGi as parameters. The start frequency function fb is updated every time the compression/expansion dual-purpose machine 14 is started. The starting order function fb may be expressed by the following equation (3) with a constant value of each of a3 and a4 being positive, for example.

[ numerical formula 3 ]

。

The inversion frequency function fc is a function of accumulating inversion frequencies, and includes the switching frequency GCi as a parameter. The reverse rotation number function fc is updated every time the compressor-expander 14 starts reverse rotation. When the compressor-expander 14 is reversely started, the loss accompanying the switching of charge and discharge can be prevented by securing the predetermined stop time τ. Therefore, the inversion frequency function fc may be expressed by the following equation (4) with a5 being a positive constant, t being the time from the stop of the compressor/expander 14, and τ being a predetermined stop time. In the following equation (4), it is considered that the influence of the previous rotation direction is not present by the elapse of the predetermined stop time τ, and the function fc of the number of inversions is set to 0 after the elapse of the predetermined stop time τ.

[ numerical formula 4 ]

。

Next, the n units of the combined compression and expansion machine 14 are driven as generators at the rated drive and 1 unit is driven as a generator at the residual electric power (| W | -n × P) in order from the smaller fatigue amount FPi (step S5-3). Then, it is determined again whether or not the charge/discharge command value W is larger than 0 (step S5-4). When the charge/discharge command value W is equal to or less than 0 (NO: step S5-4), the charging is required to be reversed from the power generation, and the power generation is stopped (step S5-5). Then, referring to fig. 4, the charging process is executed (step S4-4). Note that reference sign a in fig. 4 and reference sign a in fig. 5 are connected in control processing.

Referring to fig. 5, when the charge/discharge command value W is greater than 0 (yes in step S5-4), the power generation process is continued, but the number of cells in rated drive is calculated as m (step S5-6). The method of calculating the number of cells m is the same as the method of calculating the number of cells n described above. If the number of cells n is equal to the number of cells m (n = m: step S5-7), the number of driving units of the combined compressor and expander 14 does not need to be increased or decreased, and therefore no special processing is performed. If the number of cells n is smaller than the number of cells m (n < m: step S5-7), the rated-drive compressor-expander 14 is additionally driven for m-n cells (step S5-8). At this time, additional driving is performed in order from the cell with the smaller fatigue amount FPi. If the number of cells n is larger than the number of cells m (n > m: step S5-7), the n-m number of cells of the combined compression and expansion machine 14 is stopped (step S5-9). At this time, the fatigue amount FPi is sequentially stopped from the larger one. After these processes are completed (step S5-7, step S5-8, step S5-9), the value of the number of cells m is updated as the value of the number of cells n (step S5-10).

Subsequently, it is determined whether or not the time T is equal to or greater than the predetermined value Tset (step S5-11). When the time T is equal to or longer than the predetermined time Tset (YES in step S5-11), the time T is reset to 0 and counted again (step S5-12), and the process returns to the process of calculating the fatigue amount FPi (step S5-2). By this reset, even when the charge/discharge command value W does not change, the driven combined compression/expansion machine 10 can be forcibly changed every time the predetermined time Tset elapses, and the same combined compression/expansion machine 10 can be prevented from being continuously used. Here, the predetermined time Tset is appropriately set according to the use conditions and the like, and may be set to about 24 hours, for example. When the time T is less than the predetermined time Tset (no: step S5-11), the control process waits for a fixed time Ti (step S5-13), and then returns to the process of determining whether the charge/discharge command value W is greater than 0 (step S5-4). The compressor-expander 10 requires a certain amount of time from the start to the completion of the start or from the start to the completion of the stop. For these, for example, several tens of seconds are required, and during this period, the driving compressor/expander 10 cannot be switched, and even if a control signal is transmitted, it may not be processed. Therefore, by waiting for the control process for about several tens of seconds as the fixed time Ti, it is possible to prevent the control signal that cannot be processed from being transmitted to the combined compression and expansion machine 10. Therefore, the start or stop of the compressor-expander 10 can be completed in the standby process.

Referring to fig. 6, in the charging process, first, the number of the compression-expansion dual-purpose machines 14 that are rated-driven as compressors is calculated (step S6-1). In the present embodiment, the number n of cells of the combined compression and expansion machine 14 that performs rated driving is calculated in the same manner as the power generation process. Here, if the rated drive output of 1 cell is P, the number of cells n is calculated as the maximum integer n not exceeding the number (n = [ | W |/P ]) obtained by dividing the charge-discharge command value W by the output P.

Next, the fatigue amount FPi for each unit of the compression/expansion dual-purpose machine 14 is calculated (step S6-2). The method of calculating the fatigue amount FPi is the same as in the case of the power generation process described above.

Next, the n units of the compression-expansion machines 14 are driven at the rated speed as compressors and the 1 compression-expansion machine 14 is driven by the surplus power (| W | -n × P) as compressors in order from the smaller fatigue amount FPi (step S6-3). Then, it is determined again whether or not the charge/discharge command value W is larger than 0 (step S6-4). When the charge/discharge command value W is 0 or less (NO: step S6-4), the charge is stopped because the power generation is required to be reversed from the charge (step S6-5). Then, the power generation process is executed with reference to fig. 4 (step S4-3). Note that reference symbol B in fig. 4 and reference symbol B in fig. 6 are connected in control processing.

Referring to fig. 6, when charge/discharge command value W is greater than 0 (yes: step S6-4), the charging process is continued, but the number of cells that are driven again at the rated value is calculated as m (step S6-6). The method of calculating the number of cells m is the same as the method of calculating the number of cells n described above. If the number of cells n is equal to the number of cells m (n = m: step S6-7), the number of driving units of the combined compressor and expander 14 does not need to be increased or decreased, and therefore no special processing is performed. If the number of cells n is smaller than the number of cells m (n < m: step S6-7), the rated-drive compressor-expander 14 is additionally driven for m-n cells (step S6-8). At this time, additional driving is performed in order from the smaller FPi. If the number of cells n is larger than the number of cells m (n > m: step S6-7), the n-m number of cells of the combined compression and expansion machine 14 is stopped (step S6-9). At this time, the fatigue amount FPi is sequentially stopped from the larger one. After these processes are completed (step S6-7, step S6-8, step S6-9), the value of the number of cells m is updated as the value of the number of cells n (step S6-10).

Subsequently, it is determined whether or not the time T is equal to or greater than the predetermined value Tset (step S6-11). When the time T is equal to or longer than the predetermined time Tset (YES in step S6-11), the time T is reset to 0 and counted again (step S6-12), and the process returns to the process of calculating the fatigue amount FPi (step S6-2). When the time T is less than the predetermined time Tset (no: step S6-11), the control process waits for a fixed time Ti (step S6-13), and then returns to the process of determining whether the charge/discharge command value W is greater than 0 (step S6-4). In addition, the meaning of the processing from step S6-10 to step S6-13 is the same as that of the processing from step S5-10 to step S5-13 described earlier with reference to FIG. 5.

As described above, in the present embodiment, when the charge/discharge command value W for switching charge/discharge is generated, the driving compressor-expander 14 is stopped, and the compressor-expander 14 having the smaller fatigue amount FPi is started in order. Here stopping and starting are performed simultaneously. The reversal frequency function fc used for calculating the fatigue amount FPi prevents a loss associated with switching between charge and discharge by ensuring a predetermined stop time τ when the compressor-expander 14 is started to reverse. Therefore, by using the inversion frequency function fc for calculating the fatigue amount FPi, the driving compressor-expander 14 is stopped and the stopped compressor-expander 14 is driven, instead of actually switching the charge and discharge of the driving compressor-expander 14. In order to reliably prevent the loss due to the switching, the degree of contribution of the inversion frequency function fc in the calculation of the fatigue amount FPi may be set to be greater than the other functions fa and fb.

According to the CAES power generation apparatus 1 of the present embodiment, the following advantageous operational effects can be obtained.

By appropriately controlling the plurality of compressors 14 as described above, the standby time associated with the switching between charging and discharging can be shortened or omitted. The CAES power generation apparatus 1 produces compressed air from the electric power (input power) generated by the wind power plant 2, stores the compressed air in the pressure accumulator 10, and generates required electric power (required power) at appropriate times from the stored compressed air. Since the balance between the input power and the required power changes with time, switching between charge and discharge may be required. In the configuration of the present embodiment, when the charge/discharge command value W for switching charge/discharge is generated, the driving combined compression/expansion machine 14 is stopped and the stopped combined compression/expansion machine 14 is driven, instead of switching charge/discharge of the driving combined compression/expansion machine 14 for use. Since the stop of the combined compression and expansion machine 14 and the start of the other combined compression and expansion machine 14 can be performed simultaneously, the standby time involved in the switching of charge and discharge can be omitted.

Further, since the driving of the combined compression and expansion machine 14 is controlled in accordance with the fatigue amount FPi, the degree of loss of the combined compression and expansion machine 14 can be made uniform. If the specific combined compression and expansion machine 14 is driven in a concentrated manner without making the loss degree uniform, the specific combined compression and expansion machine 14 needs to be maintained earlier, and the maintenance frequency of the CAES power generation apparatus 1 as a whole may increase. Therefore, in order to reduce the frequency of maintenance, it is effective to make the degree of wear uniform.

Further, the fatigue amount FPi is set based on the number of times of switching of charge and discharge by using the reversal frequency function fc for calculating the fatigue amount FPi. Therefore, the loss of the combined compressor and expander 14 can be made more uniform. In particular, the number of times of switching between charge and discharge is a parameter unique to the compressor/expander 14 that cannot be considered in a normal compressor or expander. Therefore, the loss of the combined compressor and expander 14 can be accurately made uniform.

As a modification of the present embodiment, the charge/discharge command value W may be a predicted value or a planned value of charge/discharge. The predicted value or planned value of the charge/discharge may be calculated based on the past data of the same time zone, for example. In addition, when the input power is the power generated by the wind power plant 2 as in the present embodiment, the amount of input power (amount of charge) may be predicted based on meteorological conditions such as the wind direction and the wind intensity. In addition, when the required power is the power required by the plant equipment as in the present embodiment, the prediction may be made based on the operating time of the plant equipment such as daytime or nighttime.

According to this modification, since control is performed based on the predicted value of charge and discharge, efficient control with less time delay can be performed.

While the present invention has been described with reference to the specific embodiments and modifications thereof, the present invention is not limited to the embodiments described above, and can be variously modified and implemented within the scope of the present invention. For example, the fatigue amount FPi may be set not for each unit but for each 1 unit of the compression/expansion dual-purpose machine 14, and the drive control may be performed for each 1 unit. The wind power plant 2 is an example of a device that supplies input power to the CAES power generation apparatus 1. That is, the input power may be supplied from any device. Preferably, from the viewpoint that the CAES power generation apparatus 1 has the capability of smoothing fluctuating power, the device that generates the input power may be a device that generates power from renewable energy. The supply force may be supplemented by a thermal power plant or the like, not limited to renewable energy. The compressor/expander that includes the electric motor/generator may be a multi-stage compressor/expander that performs multi-stage compression or expansion using 1 electric motor/generator.

Description of the reference numerals

1 compressed air energy storage generating set (CAES generating set)

2 wind power station

10 pressure accumulating part

11 air piping

12 heat carrier tank

13 heating medium piping

14 compression and expansion dual-purpose machine

14a electric/power generation dual-purpose machine

15 heat exchanger

16 control device

C1 container No. 1

C2 container No. 2.