阅读说明：本技术 一种变速恒频压缩空气储能发电系统 (Variable-speed constant-frequency compressed air energy storage power generation system ) 是由 刘冲 王团结 宋晓辉 李毅 杨胜林 何信林 张文斌 倪继文 杨世强 张钢 谭祥帅 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种变速恒频压缩空气储能发电系统,包括高温压缩机组、储气装置、透平发电机组、变速恒频控制系统、循环冷却水系统以及回热系统；所述高温压缩机组利用低谷电能将空气压缩成高压状态的压缩空气,将高压低温的压缩空气注入储气装置,所述储气装置与透平发电机组相连；所述回热系统用于满足透平发电机组做工的工质温度；所述循环冷却水系统用于压缩机出口气体的二次换热以及高压透平进气的初加热。所述变速恒频控制系统用于将空气透平发电机组输出的机械能通过发电机/电动机运行在发电机状态向外输出变速的电能,将高质量电能输送至电网。从而补偿释能阶段因透平转速波动造成的网侧频率波动,实现变速恒频输出。(The invention discloses a variable-speed constant-frequency compressed air energy storage power generation system which comprises a high-temperature compressor unit, a gas storage device, a turbine generator set, a variable-speed constant-frequency control system, a circulating cooling water system and a heat regeneration system, wherein the high-temperature compressor unit is connected with the gas storage device through a pipeline; the high-temperature compressor unit compresses air into high-pressure compressed air by utilizing valley electric energy, and injects the high-pressure low-temperature compressed air into the air storage device, and the air storage device is connected with the turbine generator unit; the heat regenerative system is used for meeting the working medium temperature of the turbine generator set; and the circulating cooling water system is used for secondary heat exchange of the gas at the outlet of the compressor and primary heating of the high-pressure turbine inlet gas. The variable-speed constant-frequency control system is used for outputting variable-speed electric energy to the outside when mechanical energy output by the air turbine generator set runs in a generator state through a generator/motor and transmitting high-quality electric energy to a power grid. Therefore, the network side frequency fluctuation caused by the fluctuation of the turbine rotating speed in the energy release stage is compensated, and the variable-speed constant-frequency output is realized.)

1. A variable-speed constant-frequency compressed air energy storage power generation system is characterized by comprising a high-temperature compressor unit, a gas storage device (5), a turbine generator set, a variable-speed constant-frequency control system, a circulating cooling water system and a heat regeneration system;

the high-temperature compressor unit compresses air into high-pressure compressed air by utilizing valley electric energy, the high-pressure low-temperature compressed air is injected into the air storage device (5), and the air storage device (5) is connected with the turbine generator set;

the heat regenerative system is used for meeting the working medium temperature of the turbine generator set;

and the circulating cooling water system is used for secondary heat exchange of the gas at the outlet of the compressor and primary heating of the high-pressure turbine inlet gas.

The variable-speed constant-frequency control system is used for enabling mechanical energy output by the air turbine generator set to operate in a generator state through the generator/motor (1) to output variable-speed electric energy outwards, and transmitting high-quality electric energy to a power grid.

2. The variable speed constant frequency compressed air energy-storage power generation system according to claim 1, wherein the inlet of the air storage device (5) is connected with a high temperature compressor unit, the high temperature compressor unit is connected with the synchronous generator/motor (1) through an SSS clutch (4-1) between the motor and the compressor, the outlet of the air storage device (5) is connected with a turbine generator unit, and the turbine generator unit is connected with the synchronous generator/motor (1) through an SSS clutch (4-2) between the generator and the turbine.

3. The variable-speed constant-frequency compressed air energy-storage power generation system according to claim 1, wherein the high-temperature compressor unit comprises a first-stage high-temperature compressor (2-1) and a second-stage high-temperature compressor (2-2), a circulating cooling water pump (13) is arranged between the first-stage high-temperature compressor (2-1) and the second-stage high-temperature compressor (2-2), and an inlet of the first-stage high-temperature compressor (2-1) is connected with the atmosphere through an air filter screen (15-1).

4. The variable-speed constant-frequency compressed air energy-storage power generation system of claim 1, wherein the turbine generator set comprises a first-stage air turbine (3-1) and a second-stage air turbine (3-2), the exhaust gas of the second-stage air turbine (3-2) enters the first-stage air turbine (3-1) for doing work after being subjected to heat exchange through an oil-gas heat exchanger (9-1), and the exhaust gas of the first-stage air turbine (3-1) is exhausted into the atmosphere after passing through an emptying silencer (19).

5. The variable-speed constant-frequency compressed air energy-storage power generation system according to claim 4, characterized in that a compressed air outlet of the air storage device (5) is sequentially provided with a water-gas heat exchanger (11), an air dryer (14-3) and a turbine air inlet filter screen (15-3), gas heated by the turbine air inlet filter screen (15-3) and high-temperature heat conduction oil from an outlet of the high-temperature heat storage device (7) exchange heat through an oil-gas heat exchanger (9-2), the heat-absorbed high-temperature high-pressure air enters a second-stage air turbine (3-2) for working, and an air filter screen (15-2) is arranged between the compressed air outlet of the air storage device (5) and the water-gas heat exchanger (11).

6. The variable-speed constant-frequency compressed air energy-storage power generation system according to claim 1, wherein the heat recovery system comprises a low-temperature heat storage device (6), an oil-gas heat exchanger I (8-1), an oil-gas heat exchanger II (8-2), a high-temperature heat storage device (7), an oil-gas heat exchanger III (9-1) and an oil-gas heat exchanger IV (9-2) which are sequentially connected, the low-temperature heat storage device (6) is used for storing low-temperature heat transfer oil, the oil-gas heat exchanger I (8-1) is arranged at the downstream of the first-stage high-temperature compressor (2-1), the upstream of the second-stage high-temperature compressor (2-2), the oil-gas heat exchanger II (8-2) is arranged at the downstream of the second-stage high-temperature compressor (2-2), the upstream of the gas storage device (5), the oil-gas heat exchanger I (8-1) and the oil-gas heat exchanger II (8-2) utilize the low-temperature heat transfer oil to recover pressure generated in the process of compressing air of the high-temperature compressor set The heat-reducing and high-temperature heat storage device (7) stores high-temperature heat conduction oil, the oil-gas heat exchanger III (9-1) is arranged at the downstream of the second-stage air turbine (3-2) and at the upstream of the first-stage air turbine (3-1), the oil-gas heat exchanger IV (9-2) is arranged at the downstream of the gas storage device (5) and at the upstream of the high-pressure compressor, and the oil-gas heat exchanger III (9-1) and the oil-gas heat exchanger IV (9-2) utilize the high-temperature heat conduction oil to heat compressed air released by the gas storage device (5) and are used for meeting the working medium temperature for turbine work.

7. The variable-speed constant-frequency compressed air energy-storage power generation system according to claim 1, wherein the circulating cooling water system comprises a water-gas heat exchanger (10) arranged at the downstream of the oil-gas heat exchanger (8) and at the upstream of the air storage device (5) and used for absorbing low-temperature waste heat generated after heat transfer oil at the outlet of the compressor is conducted, so as to complete secondary heat exchange on gas at the outlet of the compressor, a water-gas heat exchanger (11) arranged at the downstream of the compressed air storage device (5) and at the upstream of the oil-gas heat exchanger (9) and used for exchanging heat on high-pressure cold air from the outlet of the air storage device (5) and primarily heating the compressed air entering the second-stage air turbine (3-2), and a mechanical ventilation cooling tower (16) connected with the water-gas heat exchanger (10) so as to achieve gas-water separation and remove water vapor doped in the compressed air.

8. The system according to claim 1, wherein the variable speed constant frequency compressed air energy storage power generation system comprises a generator side switch (20), the synchronous generator/motor (1) is connected to a four-quadrant converter (21) through the generator side switch (20) to realize constant frequency control, and the electric energy with output constant frequency is filtered through a phase-shifting transformer (22) and finally connected to a main transformer (24) through a grid side switch (23).

Technical Field

The invention belongs to the technical field of electric energy storage, and particularly relates to a variable-speed constant-frequency compressed air energy storage power generation system.

Background

In the process of vigorously developing new energy such as wind, light and the like, the adverse effect is gradually highlighted. On one hand, the output of the new energy has the characteristics of volatility and intermittence, is not beneficial to the stable operation of a power grid, and seriously influences the grid connection of wind-solar power generation; on the other hand, the rapidly increased installed capacity of renewable energy and the generation form of distributed energy bring greater challenges to new energy consumption and power grid frequency modulation and peak regulation, the power grid operation is increasingly complex, and in the areas with high clean energy penetration levels such as northwest, northeast and the like, the problems of wind and light abandonment are serious, and the consumption situation of renewable energy is severe. The energy storage system can quickly and flexibly adjust the system power, so that various energy storage devices are applied to the power system and are one of effective means for solving the problems.

The energy storage has the biggest advantages of being chargeable and dischargeable, high in response speed, obvious in effect in primary frequency modulation, and suitable for power type application. The existing large-capacity electric energy storage technology applied as an electric quantity type is still immature, mature pumped storage and chemical battery energy storage can only meet the requirements of full-load discharge for 2-4 hours, the unit cost of a pumped storage power station discharging for 4 hours is about 1.6 times that of a thermal power unit, and the unit cost of the chemical battery energy storage with the 4-hour discharge capacity is about 2 times that of the thermal power unit. The development of the pumped storage power station is gradually gentle due to factors such as site construction conditions, potential ecological environment and the like. In addition, the lithium ion battery uses combustible materials, thereby increasing the probability of accidents. Therefore, the potential safety hazard of battery energy storage becomes an important factor restricting the development of the battery. In recent years, Compressed Air Energy Storage (CAES) has attracted great attention from large-scale enterprises and research institutions at home and abroad due to the advantages of large capacity, long service life, high response speed and the like.

Advanced adiabatic compressed air energy storage (AA-CAES) is a clean energy storage technology that abandons the fuel afterburning link of the conventional CAES technology by recycling air compression heat energy. AA-CAES has the characteristics of high efficiency, low cost and the like, is one of the main trends in the technical field of CAES at present, and the working principle of the AA-CAES is shown in figure 1. During energy storage, the AA-CAES drives a compressor by utilizing waste wind (light), off-peak electricity and the like, recovers compression heat through an adiabatic compression (compression system), and decouples stored air pressure potential energy (a gas storage reservoir) and compressed heat energy (a heat storage system); when releasing energy, the air pressure potential energy and the compression heat energy are coupled to release energy to generate power by utilizing the compression heat energy through adiabatic expansion (turbine system).

However, variations in environmental conditions (e.g., ambient temperature and pressure) can result in off-design operation of the system. The non-design operation enables the CAES system to be always in a non-steady state operation state, and brings difficulty to the optimal operation and control of the system. Research shows that unsteady state operation has obvious influence on the energy efficiency of the system; secondly, research shows that in the later energy release stage, along with the reduction of the air pressure in the air storage tank, the opening degree of the regulating valve is gradually increased to deviate from the regulating characteristic range, and at the moment, the rotating speed of the turbine and the outlet frequency of the generator fluctuate to a large extent.

Disclosure of Invention

In order to overcome the technical problem, the invention provides a variable-speed constant-frequency compressed air energy storage power generation system, which is used for transmitting high-quality electric energy to a power grid, so that the grid side frequency fluctuation caused by the fluctuation of the rotating speed of a turbine in the energy release stage is compensated, and the variable-speed constant-frequency output is realized.

In order to achieve the purpose, the invention adopts the technical scheme that:

a variable-speed constant-frequency compressed air energy storage power generation system comprises a high-temperature compressor unit, a gas storage device, a turbine generator unit, a variable-speed constant-frequency control system, a circulating cooling water system and a heat regeneration system;

the high-temperature compressor unit compresses air into high-pressure compressed air by utilizing valley electric energy, and injects the high-pressure low-temperature compressed air into the air storage device, and the air storage device is connected with the turbine generator unit;

the heat regenerative system is used for meeting the working medium temperature of the turbine generator set;

the circulating cooling water system is used for secondary cooling of the gas at the outlet of the compressor and primary heating of the gas storage device, namely the inlet gas of the high-pressure turbine. The cold end of the circulating cooling water system adopts a mechanical ventilation cooling tower and is provided with a variable frequency motor for regulation. After being pressurized by a circulating cooling water pump 13, the compressed air is respectively sent to a water-gas heat exchanger 10-1 at the outlet of the first-stage compressor and a water-gas heat exchanger 10-2 at the outlet of the multi-stage compressor and is used for secondarily cooling the high-temperature compressed air at the outlet of the oil-gas heat exchanger. The heat exchange between the circulating cooling water after heat absorption and the compressed air from the outlet of the air storage device is carried out through the water-gas heat exchanger 11 (heat release process), and the circulating cooling water after heat release finally returns to the mechanical ventilation cooling tower to complete the whole circulation.

The variable-speed constant-frequency control system is used for enabling mechanical energy output by the air turbine generator set to be operated in a generator state through the generator/motor 1 to output variable-speed electric energy outwards, achieving constant-frequency output through control over the converter, and transmitting high-quality electric energy to a power grid.

The inlet of the gas storage device 5 is connected with a high-temperature compressor unit, the high-temperature compressor unit is connected with a synchronous generator/motor 1 through an SSS clutch 4-1 between a motor and a compressor, the outlet of the gas storage device 5 is connected with a turbine generator set, and the turbine generator set is connected with the synchronous generator/motor 1 through an SSS clutch 4-2 between a generator and a turbine.

The high-temperature compressor unit comprises a first-stage high-temperature compressor 2-1 and a second-stage high-temperature compressor 2-2, a circulating cooling water pump 13 is arranged between the first-stage high-temperature compressor 2-1 and the second-stage high-temperature compressor 2-2, and an inlet of the first-stage high-temperature compressor 2-1 is connected with the atmosphere through an air filter screen 15-1.

The turbine generator set comprises a first-stage air turbine 3-1 and a second-stage air turbine 3-2, exhaust gas of the second-stage air turbine 3-2 enters the first-stage air turbine 3-1 to do work after being subjected to heat exchange through an oil-gas heat exchanger 9-1, and exhaust gas of the first-stage air turbine 3-1 is exhausted into the atmosphere after passing through an exhaust silencer 19.

The compressed air outlet of the air storage device 5 is sequentially provided with a water-gas heat exchanger 11, an air dryer 14-3 and a turbine air inlet filter screen 15-3, gas heated by the turbine air inlet filter screen 15-3 and high-temperature heat conducting oil from the outlet of the high-temperature heat storage device 7 exchange heat through an oil-gas heat exchanger 9-2, heat-absorbed high-temperature and high-pressure air enters a second-stage air turbine 3-2 for working, and the air filter screen 15-2 is arranged between the compressed air outlet of the air storage device 5 and the water-gas heat exchanger 11.

The heat recovery system comprises a low-temperature heat storage device 6, an oil-gas heat exchanger I8-1, an oil-gas heat exchanger II8-2, a high-temperature heat storage device 7, an oil-gas heat exchanger III9-1 and an oil-gas heat exchanger IV9-2 which are connected in sequence, wherein the low-temperature heat storage device 6 is used for storing low-temperature heat transfer oil, the oil-gas heat exchanger I8-1 is arranged at the downstream of a first-stage high-temperature compressor 2-1 and at the upstream of a second-stage high-temperature compressor 2-2, the oil-gas heat exchanger II8-2 is arranged at the downstream of the second-stage high-temperature compressor 2 and at the upstream of a gas storage device 5, the oil-gas heat exchanger I8-1 and the oil-gas heat exchanger II8-2 recover compression heat generated in the air compression process of a high-temperature compressor set by using the low-temperature heat transfer oil, the high-temperature heat storage device 7 stores high-temperature heat transfer oil, the oil-gas heat exchanger III9-1 is arranged at the downstream of a second-stage air turbine 3-2 and at the upstream of a first-stage air turbine 3-1, the oil-gas heat exchanger IV9-2 is arranged at the downstream of the gas storage device 5 and at the upstream of the high-pressure compressor, and the oil-gas heat exchanger III9-1 and the oil-gas heat exchanger IV9-2 heat compressed air released by the gas storage device 5 by using high-temperature heat conduction oil so as to meet the working medium temperature for turbine work.

The circulating cooling water system comprises a water-gas heat exchanger 10 which is arranged at the lower reaches of the oil-gas heat exchanger 8 and at the upper reaches of the air storage device 5 and used for absorbing low-temperature waste heat generated after heat exchange of heat conduction oil at the outlet of the compressor and completing secondary heat exchange of gas at the outlet of the compressor, a water-gas heat exchanger 11 which is arranged at the lower reaches of the compressed air storage device 5 and at the upper reaches of the oil-gas heat exchanger 9 and used for exchanging heat of high-pressure cold air from the outlet of the air storage device 5 and primarily heating the compressed air entering the second-stage air turbine 3-2, and a mechanical ventilation cooling tower 16 connected with the water-gas heat exchanger 10, so that gas-water separation is realized, and water vapor doped in the compressed air is removed.

The variable speed constant frequency control system comprises a generator side switch 20, a synchronous generator/motor 1 is connected into a four-quadrant converter 21 through the generator side switch 20 to realize constant frequency control, electric energy with output constant frequency is filtered through a phase-shifting transformer 22, and finally is connected into a main transformer 24 through a power grid side switch 23.

The invention has the beneficial effects that:

the invention relates to a synchronous motor, a compressor and an air turbine which are connected on the same main shaft through two SSS clutches by utilizing a four-quadrant converter, and an energy storage process and an energy release process form a complete system, wherein the energy storage stage comprises the following steps: the converter controls the motor to operate at a first quadrant time, namely the synchronous motor is in a state of storing energy by compressing air with the compressor, so that the conversion of electric energy-potential energy in the compressed air is realized; energy release stage: the converter at the first stage controls the synchronous motor to operate in an electric state to drag the turbine to increase the speed, and enables the rotating speed of the shafting to reach a target rotating speed value according to the set rotating speed and the increasing speed, so that the loss of stored energy in the flushing and rotating process is reduced, and the stability of the turbine in the flushing and rotating process is improved. And in the second energy release stage, along with the introduction of compressed air into the turbine, the synchronous motor is gradually switched from a motor state to a generator state, and the smooth reverse of the power is realized by utilizing the control of the converter. In the later energy release stage, along with the reduction of the air pressure in the air storage tank, the opening of the regulating valve is gradually increased to deviate from the regulating characteristic range, at the moment, the rotating speed of the turbine and the outlet frequency of the generator fluctuate greatly, and at the moment, the converter coordination control system participates in regulation to compensate the network side frequency fluctuation caused by the fluctuation of the rotating speed of the turbine, so that variable-speed constant-frequency output is realized.

Drawings

FIG. 1 is a schematic diagram of a prior art AA-CAES system.

Fig. 2 is a diagram of a variable speed constant frequency compressed air energy storage power generation system according to the invention.

In the figure, 1: a synchronous generator/motor; 2-1: a first stage high temperature compressor; 2-2: a second stage high temperature compressor; 3-1: a first stage air turbine; 3-2: a second stage air turbine; 4-1: SSS clutch between motor and compressor; 4-2 SSS clutch between generator and turbine; 5: a gas storage device; 6: a low temperature heat storage device; 7: a high temperature heat storage device; 8: oil-gas heat exchanger (cooler) 9: oil gas heat exchangers (regenerators); 10:

water-gas heat exchanger (recooler), 11: water-gas heat exchangers (preheaters); 12: a heat-conducting oil pump; 13: a circulating cooling water pump; 14: an air dryer; 15: an air screen; 16:

a ventilated cooling tower; 17: a low pressure bypass valve; 18: a high pressure bypass valve; 19: a muffler; 20: a generator side switch; 21: a four-quadrant converter; 22: a phase-shifting transformer; 23:

a grid side switch; 24: a main transformer.

Detailed Description

The present invention will be described in further detail with reference to examples.

As shown in fig. 1 and 2, the compressed air energy storage power generation system includes a high-temperature compressor unit, an air storage device 5, a turbine generator unit, a variable-speed constant-frequency control system, a circulating cooling water system, and a regenerative system.

The inlet of the gas storage device 5 is connected with a high-temperature compressor unit, the high-temperature compressor unit is connected with a synchronous generator/motor 1 through an SSS clutch 4-1 between the motor and the compressor, the high-temperature compressor unit operates in a motor mode to compress air in an energy storage stage, and high-pressure air compressed by the high-temperature compressor unit is stored in the gas storage device 5; the outlet of the gas storage device 5 is connected with a turbine generator set, the turbine generator set is connected with a synchronous generator/motor 1 through an SSS clutch 4-2 between a generator and a turbine, and the turbine generator set runs in a generator mode in an energy release stage to release energy release and internal energy to do work.

Shafting setting: in the compression stage, a main shaft of a motor/generator 1 is separated from a main shaft of a turbine generator set by an SSS clutch 4-1 between the motor and a compressor, the motor/generator 1 is connected with a multi-stage compressor through an SSS clutch 4-2 between the generator and the turbine to be used as an energy storage power supply in the compression stage, the multi-stage compressor is connected with a first-stage high-temperature compressor 2-1 through a reduction gearbox, and the reduction gearbox adopts a fixed transmission ratio. Providing an energy storage power supply for the first-stage high-temperature compressor 2-1; meanwhile, a first-stage air turbine 3-1 (a low-pressure turbine LT) and a second-stage air turbine 3-2 (a high-pressure turbine HT) are coaxially connected, in the working stage of the turbines, a motor/generator main shaft and a compressor main shaft are separated by an SSS clutch 4-2 between a generator and the turbines, the second-stage air turbine 3-2 is connected with a synchronous generator/motor 1 through the SSS clutch 4-1 between the motor and the compressor, and power is generated through the generator in the working process of the turbines. The compressor and the turbine can independently operate in the energy storage and release stages through the engagement/disengagement of the two SSS clutches;

wherein the regenerative system includes: 8-1 parts of an oil-gas heat exchanger I (cooler), 8-2 parts of an oil-gas heat exchanger II (cooler), 7 parts of a high-temperature heat storage device (high-temperature heat conduction oil storage tank), 9-1 parts of an oil-gas heat exchanger III (heat regenerator), 9-2 parts of an oil-gas heat exchanger IV (heat regenerator) and 6 parts of a low-temperature heat storage device (low-temperature heat conduction oil storage tank);

the low-temperature heat storage device 6, the oil-gas heat exchanger I (cooler) 8-1, the oil-gas heat exchanger II (cooler) 8-2, the high-temperature heat storage device 7, the oil-gas heat exchanger III (heat regenerator) 9-1 and the oil-gas heat exchanger IV (heat regenerator) 9-2 are sequentially connected, and the outlet of the oil-gas heat exchanger IV (heat regenerator) 9-2 is sequentially connected with the low-temperature heat storage device 6;

the low-temperature heat storage device 6 stores low-temperature heat conduction oil; the oil-gas heat exchanger I (cooler) 8-1 is arranged at the downstream of the first-stage high-temperature compressor 2-1, the upstream of the second-stage high-temperature compressor 2-2, the oil-gas heat exchanger II (cooler) 8-2 is arranged at the downstream of the second-stage high-temperature compressor 2-2, and the upstream of the gas storage device 5. The oil-gas heat exchanger I8-1 and the oil-gas heat exchanger II8-2 recover compression heat generated in the air compression process of the high-temperature compressor set by using low-temperature heat conduction oil; the high-temperature heat storage device 7 stores high-temperature heat conduction oil; the oil-gas heat exchanger III (a heat regenerator) 9-1 is arranged at the downstream of the second-stage air turbine 3-2 (a high-pressure turbine) and at the upstream of the first-stage air turbine 3-1 (a low-pressure turbine), the oil-gas heat exchanger IV (a heat regenerator) 9-2 is arranged at the downstream of the gas storage device 5 and at the upstream of the high-pressure compressor, and the oil-gas heat exchanger III9-1 and the oil-gas heat exchanger IV9-2 utilize high-temperature heat conduction oil to heat compressed air released by the gas storage device 5 so as to meet the working medium temperature for turbine working.

Wherein, recirculating cooling water system includes: and the water-gas heat exchanger (recooler) 10 is arranged at the downstream of the oil-gas heat exchanger (cooler) 8 and at the upstream of the gas storage device 5 and is used for absorbing low-temperature waste heat of the outlet of the compressor after heat exchange of heat conduction oil so as to complete secondary heat exchange of gas at the outlet of the compressor. A water-gas heat exchanger (preheater) 11 downstream of the compressed air storage device 5 and upstream of the oil-gas heat exchanger (regenerator) 9, for exchanging heat with the high-pressure cold air from the outlet of the storage device 5, and primarily heating the compressed air entering the high-pressure turbine. And a mechanical draft cooling tower 16 connected with the water-gas heat exchanger (recooler) 10 to realize gas-water separation and remove water vapor doped in the compressed air.

Wherein, four quadrant converter system includes: the generator side switch 20 may control the IEGT and the grid side switch 23 may control the IEGT. An energy storage stage: the motor is controlled to operate in a first quadrant time by the four-quadrant converter 21, namely the synchronous motor is in a state of compressing air and storing energy by a compressor, at the moment, a grid side switch 23IEGT is in rectification operation, a generator side switch 20IEGT is in inversion operation and is used as a variable frequency power supply of the compressor motor; energy release stage: the converter of the first stage controls the synchronous motor to operate in an electric state to drag the turbine to increase the speed, and enables the rotating speed of the shafting to reach a target rotating speed value according to the set rotating speed and the increasing speed. With the introduction of compressed air into the turbine, the synchronous machine is gradually switched from the motor state to the generator state, and at the moment, the power reversal is realized by the control of the converter. In the initial stage of energy release, the speed regulating system of the turbine can control the system to output in a constant speed and constant frequency operation mode. In the later energy release stage, along with the reduction of the air pressure in the air storage tank, the opening of the regulating valve is gradually increased to deviate from the regulating characteristic range, at the moment, the rotating speed of the turbine and the outlet frequency of the generator fluctuate greatly, and at the moment, the converter coordination control system participates in regulation to compensate the network side frequency fluctuation caused by the fluctuation of the rotating speed of the turbine, so that variable-speed constant-frequency output is realized.

The network side of the frequency converter is connected to the power grid through a phase-shifting transformer 22 for suppressing harmonic waves generated in the operation of the converter. Mainly the effect of low order harmonics of high amplitude.

Fig. 2 is a preferred embodiment of a variable speed constant frequency compressed air energy storage power generation system according to the present invention.

Specifically, in this embodiment, the compression stage: the high-temperature compressor set comprises a synchronous generator/motor 1 and a first-stage compressor 2-1 and a second-stage high-temperature compressor 2-2 which are connected in series, wherein an inlet of the first-stage high-temperature compressor 2-1 is connected with the atmosphere through an air filter screen 15-1, and the high-temperature compressor set compresses air into compressed air in a high-pressure state by utilizing valley electric energy. The pressurized compressed air sequentially passes through an oil-gas heat exchanger (cooler) 8-1, a water-gas heat exchanger (recooler) 10-1 and an air dryer 14-1, the primarily pressurized, cooled and dried air enters a second-stage high-temperature compressor 2-2, high-temperature and high-pressure air at the outlet of the second-stage high-temperature compressor 2-2 sequentially passes through the oil-gas heat exchanger (cooler) 8-2, the water-gas heat exchanger (recooler) 10-2 and the air dryer 14-2 to release heat, and finally the high-pressure and low-temperature compressed air is injected into the air storage device 5.

The combined turbine does work: high-pressure low-temperature compressed air from the air storage device 5 firstly enters a water-gas heat exchanger (preheater) 11 for primary heating after passing through an air filter screen 15-2, the heated air passes through an air dryer 14-3 and a turbine air inlet filter screen 15-3 and then exchanges heat with high-temperature heat conduction oil from the outlet of a high-temperature heat storage device 7 through an oil-gas heat exchanger (regenerator) 9-2, the high-temperature high-pressure air after heat absorption enters a second-stage air turbine 3-2 (high-pressure turbine) for acting, the exhaust gas of the second-stage air turbine 3-2 (high-pressure turbine) enters a first-stage air turbine 3-1 (low-pressure turbine) for acting after heat exchange through an oil-gas heat exchanger (regenerator) 9-1, and the exhaust gas of the first-stage air turbine 3-1 (low-pressure turbine) finally enters the atmosphere after passing through an exhaust silencer 19.

The circulating cooling water from the ventilation cooling tower 16 is pressurized by a circulating cooling water pump 13 and then enters a water-gas heat exchanger (recooler) 10 to absorb low-temperature waste heat at the outlet of the compressor after heat transfer of heat-conducting oil, so that secondary heat exchange of gas at the outlet of the compressor is completed, the circulating cooling water after heat absorption enters a water-gas heat exchanger (preheater) 11 to exchange heat with high-pressure cold air from the outlet of the gas storage device 5, and the compressed air entering a second-stage air turbine 3-2 (high-pressure turbine) is primarily heated.

The variable speed constant frequency control system: mechanical energy output by the combined air turbine generator set is changed in speed outwards when the generator/motor 1 operates in a generator state, the mechanical energy is connected to the four-quadrant converter 21 through the generator side switch 20 to achieve constant frequency control, the output constant frequency electric energy is filtered through the phase-shifting transformer 22, and finally is connected to the main transformer 24 through the power grid side switch 23, and finally high-quality electric energy is transmitted to a power grid.

The variable-speed constant-frequency compressed air energy storage power generation system described in the above embodiment utilizes the four-quadrant converter 21 to link the synchronous motor, the compressor and the air turbine on the same main shaft through two SSS clutches, and the energy storage process and the energy release process form a complete system, and the energy storage stage is as follows: the converter controls the motor to operate at a first quadrant time, namely the synchronous motor is in a state of storing energy by compressing air with the compressor, so that the conversion of electric energy-potential energy in the compressed air is realized; energy release stage: the converter at the first stage controls the synchronous motor to operate in an electric state to drag the turbine to increase the speed, and enables the rotating speed of the shafting to reach a target rotating speed value according to the set rotating speed and the increasing speed, so that the loss of stored energy in the flushing and rotating process is reduced, and the stability of the turbine in the flushing and rotating process is improved. And in the second energy release stage, along with the introduction of compressed air into the turbine, the synchronous motor is gradually switched from a motor state to a generator state, and the smooth reverse of the power is realized by utilizing the control of the converter. In the later energy release stage, along with the reduction of the air pressure in the air storage tank, the opening of the regulating valve is gradually increased to deviate from the regulating characteristic range, at the moment, the rotating speed of the turbine and the outlet frequency of the generator fluctuate greatly, and at the moment, the converter coordination control system participates in regulation to compensate the network side frequency fluctuation caused by the fluctuation of the rotating speed of the turbine, so that variable-speed constant-frequency output is realized.

The specific embodiments described in this example are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.