CN205595802U - A and web frame for compressed air energy storage system - Google Patents

Abstract

The utility model discloses an and web frame for compressed air energy storage system, loop through during motor side converter, DCDC converter, grid -connected inverter insert AC electric network its characterized in that including the electric energy of energy storage equipment: and the web frame be equipped with and loop through motor side inner ring controller and motor behind the state information of motor side real -time collect motor of outer loop controller and motor side converter and incline the PWM generator and incline motor rotation number, direct current side voltage, the quick -witted terminal voltage of converter to the motor and control, since the above structure is adopted, the utility model discloses ensure that the load characteristics when the energy storage of compressed air energy storage system is stable, conversion efficiency is high to when the electric wire netting is in the load low ebb, realize the extensive storage of electric energy.

Description

A grid-connected structure for compressed air energy storage system

technical field

The utility model relates to the technical field of compressed air energy storage, in particular to a grid-connected structure for a compressed air energy storage system.

Background technique

Compressed air energy storage (CAES) uses high-pressure air to store electricity. During the energy storage process, the electricity drives the compressor (or directly driven by mechanical energy) to compress the air and store it in the air storage chamber; during the energy release process, the high-pressure air is released to expand and do work, driving the generator to output electricity.

Compared with other energy storage technologies, the compressed air energy storage system has the characteristics of low investment, low operation and maintenance costs, fast dynamic response, flexible operation mode, high economic performance, low environmental pollution, and small footprint, and has gradually attracted the attention of various countries. . Developed countries such as Germany, the United States, Japan, and Italy all have compressed air energy storage power stations under construction. my country's vigorous development of compressed air energy storage technology has important strategic significance in terms of economy, society and national security, and it can promote the rapid development of my country's smart grid-related industries and major equipment manufacturing technologies.

However, the current shortage and deficiency in the basic theory and experimental system research of compressed air energy storage, and the current research on compressed air energy storage systems have not yet broken through key technologies such as grid connection, which severely restricts the further development of compressed air energy storage systems.

Aiming at the above problems, a new grid-connected structure is provided to ensure that the compressed air energy storage system has stable load characteristics and high conversion efficiency during energy storage, and realizes large-scale storage of electric energy when the grid is in a low load.

Utility model content

The technical problem to be solved by the utility model is to provide a grid-connected structure for the compressed air energy storage system, to ensure that the compressed air energy storage system has stable load characteristics and high conversion efficiency during energy storage, and when the power grid is at a low load, Realize large-scale storage of electric energy.

In order to achieve the above purpose, the technical solution of this utility model is a grid-connected structure for compressed air energy storage system, including the electric energy of the energy storage equipment through the motor side converter, DC/DC converter, grid-connected inverter The inverter is connected to the AC power grid, and it is characterized in that: the grid-connected structure is equipped with a motor-side outer-loop controller to collect the state information of the motor and the motor-side converter in real time, and then passes through the motor-side inner-loop controller and the motor The side PWM generator controls the motor speed, DC side voltage, and machine terminal voltage of the motor side converter; the grid-connected structure is equipped with a voltage and power calculation unit to collect the voltage and power of the AC grid in real time and send them to the outside of the grid. The loop controller generates a reference signal to the grid-connected inner loop controller, and the grid-connected inner-loop controller regulates the current of the grid-connected inverter through the grid-connected PWM generator; the grid-connected structure is equipped with an outer loop controller to collect and store After the voltage signal of the energy equipment, the parameter reference signal is sent to the inner loop controller, and the inner loop controller regulates the current of the DC/DC converter through the PWM generator.

The motor-side inner-loop controller outputs a reference signal to the motor-side outer-loop controller.

The grid-connected inner loop controller collects current information of the AC grid.

The inner loop controller collects the current information of the energy storage device in real time.

A grid-connected structure for a compressed air energy storage system. Due to the adoption of the above-mentioned structure, the utility model ensures that the compressed air energy storage system has stable load characteristics and high conversion efficiency during energy storage, and realizes electric energy when the grid is in a low load. large-scale storage.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail;

Fig. 1 is a connection schematic diagram of a grid-connected structure for a compressed air energy storage system of the present invention;

Fig. 2 is a schematic diagram of the connection of the motor-side converter in the grid-connected structure of the compressed air energy storage system of the present invention;

Fig. 3 is a schematic diagram of the connection of the grid-connected inverter in the grid-connected structure of the compressed air energy storage system of the present invention;

Fig. 4 is a connection schematic diagram of a DC/DC converter in a grid-connected structure of a compressed air energy storage system according to the present invention;

In Figure 1-4, 1. Converter on the motor side; 2. DC/DC converter; 3. Grid-connected inverter; 4. Energy storage equipment; 5. AC power grid; 6. Outer loop controller on the motor side ; 7. Motor side inner loop controller; 8. Motor side PWM generator; 9. Grid-connected outer loop controller; 10. Grid-connected inner loop controller; 11. Grid-connected PWM generator; 12. Outer loop controller ; 13. Inner loop controller; 14. PWM generator; 15. Voltage and power calculation unit.

detailed description

AC compressed air energy storage system mainly includes compressed air energy storage system and flywheel energy storage system. Both of these energy storage systems need to be coupled with motors, and AC motors are often used in power system applications. Therefore, these two energy storage systems are classified as AC energy storage systems. The structure of the AC distributed energy storage system is similar in that it absorbs or sends out power through the AC motor; the system generally uses high-speed permanent magnet synchronous motors, induction motors, etc., and needs to rectify and reverse high-frequency AC power. After the transformation, it becomes the alternating current of industrial frequency and is connected to the grid.

Since the AC energy storage system is generally coupled with a high-speed motor, it needs to be connected to the grid after being rectified and inverted by a power electronic device. A typical grid-connected structure consists of a motor-side converter and a grid-connected inverter. A DC/DC converter is added to the converter and grid-connected inverter, and its main function is to boost the DC output voltage of the converter on the motor side.

Specifically as shown in Figures 1-4, the utility model includes the electric energy of the energy storage device 4 connected to the AC power grid 5 through the motor-side converter 1, DC/DC converter 2, and grid-connected inverter 3 in sequence. It is characterized in that: the grid-connected structure is provided with a motor-side outer loop controller 6 to collect the state information of the motor and the motor-side converter 1 in real time, and then through the motor-side inner-loop controller 7 and the motor-side PWM generator 8 to control the motor The motor speed, DC side voltage, and machine terminal voltage of the side converter 1 are controlled; the grid-connected structure is provided with a voltage and power calculation unit 15 to collect the voltage and power of the AC grid 5 in real time and send them to the grid-connected outer loop controller 9 Generate a reference signal to the grid-connected inner loop controller 10, and the grid-connected inner-loop controller 10 regulates the current of the grid-connected inverter 3 through the grid-connected PWM generator 11; the grid-connected structure is provided with an outer loop controller 12 After collecting the voltage signal of the energy storage device 4, the parameter reference signal is sent to the inner loop controller 13, and the inner loop controller 13 regulates the current of the DC/DC converter 2 through the PWM generator 14.

The inner loop controller 7 on the motor side outputs a reference signal to the outer loop controller 6 on the motor side. The grid-connected inner-loop controller 10 collects current information of the AC grid 5 . The inner loop controller 13 collects the current information of the energy storage device 4 in real time.

The control system of the motor side converter 1 mainly controls the motor, and the permanent magnet synchronous motor is mostly used in the compressed air energy storage system, and only the control during discharge needs to be considered. Generally speaking, regardless of the type of motor used in the AC energy storage system and the working mode, the motor-side converter 1 can adopt a double-loop control structure. According to different control objectives, the outer loop controller 6 on the motor side can control electrical quantities such as motor speed, DC side voltage, and machine terminal voltage, and obtain the reference signal from the inner loop controller 7 on the motor side; the inner loop generally adopts PI control The converter controls the motor current and generates the modulation signal for the converter.

There are many types of grid-connected inverters 3. According to the nature of the DC side power supply, they can be divided into voltage-type inverters and current-type inverters; according to the number of phases of the output voltage, they can be divided into single-phase inverters and three-phase inverters. Phase inverters and multi-phase inverters; in addition, they can also be classified according to the number of output voltage levels, voltage waveform type, frequency, and whether there is isolation. The control structure of the grid-connected inverter 3 adopts a double-loop control structure, in which the grid-connected outer loop controller 9 is mainly used to reflect different control purposes, and generates the current reference signal of the inner loop, and the dynamic response is relatively slow; the grid-connected inner loop controller 10 It mainly performs fine and fast current regulation, and the dynamic response is fast.

When the application scenarios of the energy storage system are different, the grid-connected inverter 3 needs to adopt different control strategies, and the difference in control strategies is mainly reflected in the outer loop control of the inverter. Common outer-loop control methods for energy storage grid-connected inverters include: constant power control (PQ control), constant voltage and constant frequency control (V/f control), and droop control (Droop control). The main function of constant power control is to make the active and reactive power output by the inverter follow the power reference value, and its essence is to control the active power and reactive power separately after decoupling. The function of constant voltage and constant frequency control is to keep the amplitude and frequency of the AC voltage at the outlet of the inverter unchanged by adjusting the output power of the inverter. It is generally used in the case of independent operation of the microgrid. Droop control is a control method for simulating the "power-frequency static characteristics" of generator sets. It uses the principle that the active power and reactive power injected into the AC grid are linearly related to the voltage phase angle and amplitude. There are two basic types of droop control: The method: control the output power by adjusting the voltage frequency and amplitude; control the voltage frequency and amplitude by adjusting the output power.

Compared with the inverter, the control of the DC/DC converter 2 involves direct current flow and does not involve coordinate transformation, which is relatively simple. The control of the DC/DC converter 2 also adopts a double-loop structure. The outer loop controller 12 generates reference signals for the inner loop according to different control purposes, and the inner loop controller 13 performs rapid current regulation.

The utility model provides a sharp tool for realizing the flexible interaction of the whole process of "source-network-load" with its good power supply characteristics and load characteristics. When used as load energy storage, when compressed air is used for energy storage, the load characteristics are stable and the conversion efficiency is high. Especially when the output of wind power and photovoltaic power is large and the power grid is at a low load, large-scale storage of electric energy can promote the development of new energy power generation and avoid The waste of resources such as abandoning wind and photovoltaics is of positive significance; and when wind power and photovoltaics have no output and the power grid is at peak load, the quick response will make up for the power gap for the power grid, provide continuous and stable power, and ensure the safe and stable operation of the power grid.

The utility model has been exemplarily described above in conjunction with the accompanying drawings. Obviously, the specific implementation of the utility model is not limited by the above method, as long as the various improvements made by the technical solution of the utility model are adopted, or directly applied to other occasions without improvement All are within the protection scope of the present utility model.

Claims (4)

1., for a grid connected structure for compressed-air energy-storage system, the electric energy including energy storage device (4) passes sequentially through motor side Current transformer (1), DC/DC changer (2), combining inverter (3) are linked in AC network (5), it is characterised in that: described also Web frame is provided with outside motor side and leads to successively after the status information of ring controller (6) motor in real time and motor side current transformer (1) Cross ring controller (7) and motor side PWM generator (8) in motor side to the motor speed of motor side current transformer (1), DC side electricity Pressure, set end voltage are controlled；Described grid connected structure is provided with voltage power computing unit (15) Real-time Collection AC network (5) Voltage and power be transported to grid-connected outer ring controller (9) and produce reference signal to grid-connected interior ring controller (10), grid-connected interior Ring controller (10) carries out electric current regulation by grid-connected PWM generator (11) to combining inverter (3)；Described grid connected structure sets Ring controller (13) in parameter reference signal is sent into after having outer ring controller (12) to gather the voltage signal of energy storage device (4), interior Ring controller (13) carries out electric current regulation by PWM generator (14) to DC/DC changer (2).

A kind of grid connected structure for compressed-air energy-storage system the most according to claim 1, it is characterised in that: described In motor side, ring controller (7) output reference signal is to the outer ring controller (6) of motor side.

A kind of grid connected structure for compressed-air energy-storage system the most according to claim 1, it is characterised in that: described Grid-connected interior ring controller (10) gathers the current information of AC network (5).

A kind of grid connected structure for compressed-air energy-storage system the most according to claim 1, it is characterised in that: described The current information of interior ring controller (13) Real-time Collection energy storage device (4).