Method and system for adjusting output power of turbine expander of compressed air energy storage power station

Abstract

The present invention relates to the field of energy storage technology, and provides a method and system for regulating the output power of a turbine expander of a compressed air energy storage power station, the method comprising: S1 main PID controller controls the output power of the turbine expander: the input is the deviation between the actual output power of the turbine expander and the power demanded on the grid side, and the output is the calculated value of the air flow; S2 auxiliary PID controller controls the air flow entering the turbine expander through a regulating valve: the input is the sum of the deviation between the calculated value of the air flow and the actual value of the air flow and the theoretical value of the air flow, and the output is the opening of the air regulating valve at the outlet of the gas storage reservoir. The system comprises a system, including a gas storage reservoir, an air regulating valve at the outlet of the gas storage reservoir, a heat exchanger, a turbine expander, a generator, an air flow meter and a control system. The present invention adopts a cascade PID control method to quickly respond to changes in power demand, can obtain higher control accuracy, ensure the stability of the output power, and improve the power supply quality and reliability of the power system.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a method and system for regulating the output power of a turbine expander of a compressed air energy storage power station. Background Art

[0002] In extremely bad weather, renewable energy generation is severely affected, and long-term energy storage can cope with the imbalance of electricity supply and demand caused by seasonal climate or extreme weather. Compressed air energy storage, as a long-term energy storage, has the characteristics of large capacity, high safety, long service life and low construction cost. It can promote energy transformation and green and low-carbon development, and help the rapid development of new power systems.

[0003] During the energy storage stage, compressed air energy storage uses off-peak electricity, abandoned wind and solar power and other resources to convert electrical energy into high-pressure air internal energy and store it in the gas storage reservoir. During peak electricity consumption, the high-pressure air internal energy in the gas storage reservoir is converted into electrical energy. As an important part of the power system, the precise control of its power generation is crucial to the stable operation of the power system. During the power generation process, by precisely controlling the operating parameters and power generation strategy of the turbine expander, it can be ensured that the compressed air energy storage system converts the stored energy into electrical energy with the highest efficiency, thereby improving the utilization efficiency of the entire energy system.

[0004] The energy release process of the turbo expander mainly includes the start-up rush before grid connection, the power increase stage after grid connection, and the stable power output stage. In the power control process, the control system usually transmits the difference signal to the valve opening through the feedback loop according to the difference between the power command required by the grid side and the current output power, and controls the air flow entering the turbo expander by controlling the valve opening. The feedback loop usually adopts single-stage PID control, the control process is relatively simple, there is a certain lag, and the control accuracy is poor. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method and system for regulating the output power of a turbine expander in a compressed air energy storage power station, thereby effectively improving the power supply quality and reliability of the power system.

[0006] The present invention adopts the following technical solution:

[0007] On the one hand, the present invention provides a method for adjusting the output power of a turbine expander of a compressed air energy storage power station, wherein the method uses a cascade PID controller to control the output power of the turbine expander and the opening of an air regulating valve at an outlet of a gas storage reservoir, respectively, and specifically includes:

[0008] S1. Main PID controller controls the output power of the turbine expander: the input of the main PID controller is the deviation between the actual output power of the turbine expander and the power required on the grid side, and the output is the calculated value of the air flow;

[0009] S2, the auxiliary PID controller controls the air flow entering the turbine expander through the regulating valve: the input of the auxiliary PID controller is the sum of the deviation between the calculated air flow value obtained in step S1 and the actual air flow value and the theoretical air flow value, and the output is the opening of the air regulating valve at the outlet of the gas storage reservoir; the theoretical air flow value is calculated by the turbine expander model;

[0010] S3. According to the changing power demand on the grid side, the actual output power of the turbine expander and the actual value of the air flow at the corresponding moment are collected, and steps S1 and S2 are continuously repeated to realize continuous control of the turbine expander and the air regulating valve at the outlet of the gas storage reservoir.

[0011] According to the above aspects and any possible implementation, an implementation is further provided, in step S2, the turbine expander model is as follows (1):

[0012]

[0013] Where: W is the output power of the turbine expander; G is the air flow rate at the outlet of the gas storage; C p is the specific heat capacity; T is the inlet temperature of the turbine expander; π is the expansion ratio; k is the isentropic index; η is the efficiency;

[0014] The calculation method of the theoretical air flow rate is as follows: the power demanded on the grid side of the expander is used as the output power of the turbine expander, and the power demanded on the grid side of the expander, the inlet design temperature, the design expansion ratio and the design efficiency are substituted into formula (1) to obtain the theoretical air flow rate.

[0015] According to the aspects described above and any possible implementation method, an implementation method is further provided. In step S1 and step S2, the parameters of the main PID controller and the sub-PID controller include proportional coefficients, integral coefficients and differential coefficients, which are optimized using a particle swarm optimization algorithm.

[0016] According to the aspects described above and any possible implementation method, an implementation method is further provided. In step S1 and step S2, the parameters of the main PID controller and the sub-PID controller include proportional coefficients, integral coefficients and differential coefficients, which are obtained through neural network training.

[0017] On the other hand, the present invention also provides a compressed air energy storage power station turbine expander output power regulation system, including a gas storage reservoir, a gas storage reservoir outlet air regulating valve, a heat exchanger, a turbine expander, a generator, an air flow meter and a control system;

[0018] The air regulating valve at the gas storage outlet is opened, and the low-temperature and high-pressure air in the gas storage passes through the air regulating valve at the gas storage outlet, enters the heat exchanger for heat exchange, and is converted into high-pressure and high-temperature air, and then enters the turbine expander. The high-temperature and high-pressure air drives the turbine expander impeller to rotate, and then drives the generator to do work, which is converted into output power of the turbine expander;

[0019] The air flow meter is used to measure the air flow through the air regulating valve at the outlet of the gas storage reservoir;

[0020] The control system is respectively connected to the air regulating valve at the gas storage outlet and the turbine expander by signals;

[0021] The control system uses the above method to regulate and control the turbine expander and the air regulating valve at the gas storage outlet.

[0022] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the air flow meter is disposed between the air storage reservoir and the air regulating valve at the air storage reservoir outlet.

[0023] According to the aspects described above and any possible implementation, there is further provided an implementation, wherein the control system includes a main PID controller and a sub-PID controller, which are integrated into a computer.

[0024] The beneficial effects of the present invention are:

[0025] 1. In the cascade PID control method provided by the present invention, the sub-PID controller controls the air flow. By setting the sub-PID controller, the valve can respond quickly and control the air flow entering the air turbine, thereby ensuring the stability of the output power.

[0026] 2. The cascade PID control method provided by the present invention, in which the main PID controller controls the output power of the air turbine, can accurately calculate the actual value of the output power according to the power demand on the grid side, thereby improving the power supply quality and reliability of the power system.

[0027] 3. The output power regulation method provided by the present invention fully considers the physical model of the air turbine. In the auxiliary PID control process, a theoretical air flow feedforward control is set, which enables the controller to control the opening of the air flow valve in a timely and accurate manner and quickly respond to changes in power demand.

[0028] 4. By setting up a feedforward-based cascade PID control strategy, the control system can be flexibly adjusted according to different operating conditions and load conditions, and the air flow release in the gas storage tank can be controlled according to actual needs.

[0029] 5. The present invention adopts the particle swarm optimization algorithm to optimize the parameters of the main PID controller and the auxiliary PID controller, which greatly improves the control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown is a schematic diagram of a method for adjusting the output power of a turbine expander of a compressed air energy storage power station according to an embodiment of the present invention.

[0031] Figure 2 Shown is a schematic structural diagram of an output power regulation system of a turbine expander of a compressed air energy storage power station according to an embodiment of the present invention.

[0032] In the figure: 1-gas storage; 2-gas storage outlet air regulating valve; 3-heat exchanger; 4-turbine expander; 5-generator; 6-control system; 7-air flow meter. DETAILED DESCRIPTION

[0033] The specific embodiments of the present invention will be described in detail below in conjunction with specific drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated, and they can be combined with each other to achieve better technical effects.

[0034] like Figure 1 As shown, an embodiment of the present invention provides a method for adjusting the output power of a turbine expander of a compressed air energy storage power station, wherein the method uses a cascade PID controller to control the output power of the turbine expander and the opening of the air regulating valve at the outlet of the gas storage reservoir, respectively, and specifically includes:

[0035] S1. Main PID controller controls the output power of the turbine expander: the input of the main PID controller is the deviation between the actual output power of the turbine expander and the power required on the grid side, and the output is the calculated value of the air flow;

[0036] S2, the auxiliary PID controller controls the air flow entering the turbine expander through the regulating valve: the input of the auxiliary PID controller is the sum of the deviation between the calculated air flow value obtained in step S1 and the actual air flow value and the theoretical air flow value, and the output is the opening of the air regulating valve at the outlet of the gas storage reservoir; the theoretical air flow value is calculated by the turbine expander model;

[0037] S3. According to the changing power demand of the grid side, collect the actual output power of the turbine expander and the actual value of the air flow at the corresponding moment, and repeat steps S1 and S2 continuously to realize the continuous control of the turbine expander and the air regulating valve at the outlet of the gas storage reservoir.

[0038] In a specific embodiment, in step S2, the turboexpander model is as follows (1):

[0039]

[0040] Where: W is the output power of the turbine expander; G is the air flow rate at the outlet of the gas storage; C p is the specific heat capacity; T is the inlet temperature of the turbine expander; π is the expansion ratio; k is the isentropic index; η is the efficiency;

[0041] The calculation method of the theoretical air flow rate is as follows: the power demanded on the grid side of the expander is used as the output power of the turbine expander, and the power demanded on the grid side of the expander, the inlet design temperature, the design expansion ratio and the design efficiency are substituted into formula (1) to obtain the theoretical air flow rate.

[0042] In a specific embodiment, in step S1 and step S2, the parameters of the main PID controller and the sub-PID controller include proportional coefficients, integral coefficients and differential coefficients, which are optimized using a particle swarm optimization algorithm.

[0043] Each particle of the particle swarm optimization algorithm represents a set of possible PID control parameters (proportional coefficient, integral coefficient and differential coefficient), and these initial parameters constitute the search starting point of the algorithm. The fitness function is used to evaluate the optimization process. The particle swarm algorithm parameters include the number of particle swarms, the maximum number of iterations, the inertia weight, the acceleration constant, etc. These parameters control the search behavior and efficiency of the particle swarm algorithm. The output of the particle swarm optimization algorithm is the optimized optimal PID parameters (proportional coefficient, integral coefficient and differential coefficient).

[0044] In a specific embodiment, in step S1 and step S2, the parameters of the main PID controller and the sub-PID controller include a proportional coefficient, an integral coefficient and a differential coefficient, which are obtained through neural network training.

[0045] like Figure 2 As shown, an embodiment of the present invention is a compressed air energy storage power station turbine expander output power regulation system, including a gas storage reservoir, a gas storage reservoir outlet air regulating valve, a heat exchanger, a turbine expander, a generator, an air flow meter and a control system;

[0046] The air regulating valve at the gas storage outlet is opened, and the low-temperature and high-pressure air in the gas storage passes through the air regulating valve at the gas storage outlet, enters the heat exchanger for heat exchange, and is converted into high-pressure and high-temperature air, and then enters the turbine expander. The high-temperature and high-pressure air drives the turbine expander impeller to rotate, and then drives the generator to do work, which is converted into output power of the turbine expander;

[0047] The air flow meter is used to measure the air flow through the air regulating valve at the outlet of the gas storage reservoir;

[0048] The control system is respectively connected to the air regulating valve at the gas storage outlet and the turbine expander by signals;

[0049] The control system uses the above method to regulate and control the turbine expander and the air regulating valve at the gas storage outlet.

[0050] In a specific embodiment, the air flow meter is disposed between the air storage reservoir and the air regulating valve at the outlet of the air storage reservoir.

[0051] According to the aspects described above and any possible implementation, there is further provided an implementation, wherein the control system includes a main PID controller and a sub-PID controller, which are integrated into a computer.

[0052] The control system calculates the opening of the air regulating valve at the outlet of the gas storage reservoir based on the power demand value on the grid side, the actual air flow value measured by the air flow meter, and the theoretical air flow value calculated based on the turbine expander model, and adjusts the air flow entering the turbine expander.

[0053] The present invention adopts a cascade PID control method to quickly respond to changes in power demand, thereby achieving higher control accuracy, ensuring the stability of output power, and improving the power supply quality and reliability of the power system.

[0054] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A method for adjusting the output power of a turbine expander of a compressed air energy storage power station, characterized in that: The method adopts a cascade PID controller to control the output power of the turbine expander and the opening of the air regulating valve at the gas storage outlet respectively, and specifically includes: S1. Main PID controller controls the output power of the turbine expander: the input of the main PID controller is the deviation between the actual output power of the turbine expander and the power required on the grid side, and the output is the calculated value of the air flow; S2, the auxiliary PID controller controls the air flow entering the turbine expander through the regulating valve: the input of the auxiliary PID controller is the sum of the deviation between the calculated air flow value obtained in step S1 and the actual air flow value and the theoretical air flow value, and the output is the opening of the air regulating valve at the outlet of the gas storage reservoir; the theoretical air flow value is calculated by the turbine expander model; S3. According to the changing power demand on the grid side, the actual output power of the turbine expander and the actual value of the air flow at the corresponding moment are collected, and steps S1 and S2 are continuously repeated to realize continuous control of the turbine expander and the air regulating valve at the outlet of the gas storage reservoir.

2. The method for adjusting the output power of a turbine expander of a compressed air energy storage power station according to claim 1, characterized in that: In step S2, the turboexpander model is as follows: Where: W is the output power of the turbine expander; G is the air flow rate at the outlet of the gas storage; C p is the specific heat capacity; T is the turbine expander inlet temperature; π is the expansion ratio; k is the isentropic index; η is efficiency; The calculation method of the theoretical air flow rate is as follows: the power demanded on the grid side of the expander is used as the output power of the turbine expander, and the power demanded on the grid side of the expander, the inlet design temperature, the design expansion ratio and the design efficiency are substituted into formula (1) to obtain the theoretical air flow rate.

3. The method for adjusting the output power of a turbine expander of a compressed air energy storage power station according to claim 1, characterized in that: In step S1 and step S2, the parameters of the main PID controller and the sub-PID controller include proportional coefficient, integral coefficient and differential coefficient, which are optimized by particle swarm optimization algorithm.

4. The method for adjusting the output power of a turbine expander of a compressed air energy storage power station according to claim 1, characterized in that: In step S1 and step S2, the parameters of the main PID controller and the auxiliary PID controller include proportional coefficients, integral coefficients and differential coefficients, which are obtained through neural network training.

5. A compressed air energy storage power station turbine expander output power regulation system, characterized in that: The system includes a gas storage, an air regulating valve at the outlet of the gas storage, a heat exchanger, a turbine expander, a generator, an air flow meter and a control system; The air regulating valve at the gas storage outlet is opened, and the low-temperature and high-pressure air in the gas storage passes through the air regulating valve at the gas storage outlet, enters the heat exchanger for heat exchange, and is converted into high-pressure and high-temperature air, and then enters the turbine expander. The high-temperature and high-pressure air drives the turbine expander impeller to rotate, and then drives the generator to do work, which is converted into output power of the turbine expander; The air flow meter is used to measure the air flow through the air regulating valve at the outlet of the gas storage reservoir; The control system is respectively connected to the air regulating valve at the gas storage outlet and the turbine expander by signals; The control system adopts the method described in any one of claims 1 to 4 to regulate and control the turbine expander and the air regulating valve at the gas storage outlet.

6. The compressed air energy storage power station turbine expander output power regulation system according to claim 5, characterized in that: The air flow meter is arranged between the air storage reservoir and the air regulating valve at the air storage reservoir outlet.

7. The compressed air energy storage power station turbine expander output power regulation system according to claim 5, characterized in that: The control system comprises a main PID controller and a sub-PID controller, which are integrated in a computer.

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