Power grid frequency modulation system

Abstract

The utility model provides a power grid frequency modulation system comprising a distributed flywheel energy storage system and a phase shifter which are connected in sequence, and the phase shifter is connected to a power grid. The distributed flywheel energy storage system is used for outputting voltage required by a power grid to the phase shifter; the phase shifter is used for adjusting the phase of the voltage and outputting the phase-advanced target voltage to the power grid so as to adjust the frequency of the power grid. According to the power grid frequency modulation system, the phase shifter is connected in series, so that the output voltage phase is ahead of the voltage of the power grid side, the flywheel inertia output is achieved, the inertia support function of the flywheel on the power grid is increased, and the market application is expanded.

Description

TECHNICAL FIELD

[0001] The utility model relates to flywheel technical field especially is related to a power grid frequency modulation system. BACKGROUND

[0002] The existing flywheel energy storage system supplies power to the power grid through power electronic conversion, but because of the decoupling control of power electronics, the original inertia of the flywheel cannot pass through the power electronics, so the application range of the flywheel is limited to a very narrow application market. SUMMARY

[0003] The utility model discloses a power grid frequency modulation system, to reach flywheel inertia output, increase the inertia support of flywheel to the power grid's function, expand market application.

[0004] The utility model provides a kind of power grid frequency modulation system, comprising: the distributed flywheel energy storage system and phase shifter connected in turn, and phase shifter is connected on power grid;

[0005] Distributed flywheel energy storage system is used to output the voltage required by power grid to phase shifter;

[0006] Phase shifter is used to adjust the phase of voltage, and output target voltage ahead of phase to power grid, to adjust the frequency of power grid.

[0007] Further, the distributed flywheel energy storage system includes at least one distributed flywheel energy storage unit, and a plurality of distributed flywheel energy storage units are connected in parallel on the phase shifter.

[0008] Further, each distributed flywheel energy storage unit includes distributed flywheel energy storage device and power converter connected in turn: power converter is connected with phase shifter;

[0009] Distributed flywheel energy storage device is used to output second voltage to power converter;

[0010] Power converter is used to convert second voltage into voltage required by power grid and output to phase shifter.

[0011] Further, it further includes controller, and controller is connected with phase shifter, each power converter and each distributed flywheel energy storage device respectively.

[0012] Further, it further includes acquisition unit, and acquisition unit is connected with controller and power grid respectively;

[0013] Acquisition unit is used to determine the frequency deviation of power grid, and sends frequency deviation to controller.

[0014] Further, acquisition unit includes acquisition device, filtering device and analysis device connected in turn;Acquisition device is connected with power grid, and analysis device is connected with controller.

[0015] The acquisition device is used for acquiring the voltage of the power grid.

[0016] The filtering device is used for filtering the voltage to obtain the required voltage of the power grid.

[0017] The analysis device is used for performing frequency analysis on the required voltage of the power grid to obtain the frequency deviation of the power grid and sending the frequency deviation to the controller.

[0018] Further, each distributed flywheel energy storage device comprises a motor and a flywheel body connected in sequence; each motor is connected with the controller and the corresponding power converter, respectively.

[0019] Further, each power converter comprises an input end, a control circuit, a power switch and an output end; the input end, the control circuit and the output end of each power converter are connected in sequence, each input end is further connected with the corresponding motor, each output end is further connected with the phase shifter, and each control circuit is further connected with the controller and the corresponding power switch.

[0020] Further, the phase shifter is a synchronous phase shifter.

[0021] Further, the power converter is a bidirectional power converter.

[0022] The power grid frequency modulation system provided by the utility model, include: distributed flywheel energy storage system and phase shifter connected in sequence, phase shifter is connected on the power grid, distributed flywheel energy storage system is used for outputting the voltage required by power grid to phase shifter, phase shifter is used for adjusting the phase of voltage, and output target voltage of phase advance to power grid, so as to adjust the frequency of power grid. The power grid frequency modulation system can make the output voltage phase advance the voltage of power grid side by connecting in series phase shifter, reach flywheel inertia output, increase the inertia support function of flywheel to power grid, expand market application. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the specific embodiment of the utility model or the technical scheme in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiment or the prior art description, and obviously, the drawings in the following description are some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creative labor.

[0024] Figure 1 The structure diagram of the power grid frequency modulation system provided by the embodiment of the utility model is shown in the figure.

[0025] Figure 2 The structure diagram of another power grid frequency modulation system provided by the embodiment of the utility model is shown in the figure.

[0026] Figure 3 Another structure schematic diagram of power grid frequency modulation system provided by the utility model embodiment;

[0027] Figure 4 Another structure schematic diagram of power grid frequency modulation system provided by the utility model embodiment;

[0028] Figure 5 Another structure schematic diagram of power grid frequency modulation system provided by the utility model embodiment;

[0029] Figure 6 Another structure schematic diagram of power grid frequency modulation system provided by the utility model embodiment;

[0030] Figure 7 Another structure schematic diagram of power grid frequency modulation system provided by the utility model embodiment;

[0031] Figure 8 Another structure schematic diagram of power grid frequency modulation system provided by the utility model embodiment;

[0032] Figure 9 Another structure schematic diagram of power grid frequency modulation system provided by the utility model embodiment;

[0033] Icon:

[0034] 1-flywheel energy storage system;11-distributed flywheel energy storage unit;111-distributed flywheel energy storage device;112-power converter;1111-motor;1112-flywheel body;1121-input end;1122-control circuit;1123-power switch;1124-output end;2-phase shifter;3-power grid;4-controller;5-acquisition unit;51-acquisition device;52-filtering device;53-analysis device.

[0035] Power grid frequency modulation system DETAILED DESCRIPTION

[0036] The technical solutions of the utility model will be described clearly and completely below in combination with embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0037] In practical applications, considering the fluctuation, instability and other characteristics of the power grid (renewable energy and mains), balancing the disturbance of the power grid system, maintaining voltage stability and maintaining dynamic balance of power generation become increasingly important. In the prior art, a flywheel energy storage system is generally used to cope with various abnormalities of the power supply and improve power quality. When energy needs to be released, the high-speed rotating flywheel drives the motor to slow down and generate electricity, and the power converter outputs the power suitable for the load requirements. That is, the power is supplied to the mains system through power electronic conversion. However, due to the decoupling control of power electronics, the original inertia of the flywheel cannot pass through the power electronics. The existing flywheel technology is limited, and the inertia inside the flywheel cannot be introduced to the power grid system. Therefore, the application range of the flywheel is limited to a very narrow application market.

[0038] Therefore, the utility model embodiment provides a power grid frequency modulation system to solve the problem that the original inertia of the flywheel cannot pass through the power electronics and the application range of the flywheel is limited to a very narrow application market. The technology can be applied to power grid frequency modulation.

[0039] In order to facilitate the understanding of the embodiment, first, a power grid frequency modulation system disclosed by the utility model embodiment is introduced in detail.

[0040] Referring to Figure 1 The utility model embodiment provides a power grid frequency modulation system, which comprises: a distributed flywheel energy storage system 1 and a phase shifter 2 connected in sequence, and the phase shifter 2 is connected to a power grid 3. The distributed flywheel energy storage system 1 is used to output the voltage required by the power grid 3 to the phase shifter 2; the phase shifter 2 is used to adjust the phase of the voltage and output the target voltage with a phase lead to the power grid 3 to adjust the frequency of the power grid 3.

[0041] Figure 1 In the embodiment, there are two intersecting circles between the phase shifter 2 and the power grid 3. It can be understood that this is a wiring method of the phase shifter device. Specifically, the upper side of the two intersecting circles is connected to the power grid side, and the lower side is connected to the flywheel side.

[0042] The above-mentioned distributed flywheel energy storage system generally comprises a flywheel body, a bearing, a motor, a power converter and a vacuum chamber.

[0043] The above-mentioned phase shifter is an electronic device used to change the phase of a signal. It can delay or advance the phase of the input signal by a certain angle, so as to realize the phase adjustment of the signal and produce phase shift. The working principle of the phase shifter can be realized in many ways. One common method is to use a voltage-controlled moving feedback circuit. By adjusting the input voltage signal, the phase shifter can change the phase of its output signal. Usually, the phase shifter provides a controllable control voltage to control the desired phase shift amount.

[0044] In actual application process, a phase shifter can be connected in series in the original system (the distributed flywheel energy storage system is directly connected with the power grid), that is, a phase shifter is connected in series between the distributed flywheel energy storage system and the power grid. When charging, the motor runs as a motor through the converter to connect the external power source, drives the flywheel to accelerate to a very high speed, converts the electric energy into kinetic energy and stores it. When discharging, the motor runs as a generator, outputs electric energy through the power converter to the phase shifter, and the speed of the flywheel gradually decreases, and the kinetic energy is converted into electric energy. First, the power converter outputs electric energy suitable for the demand of the power grid, and then the phase shifter adjusts the phase of the input voltage signal to make the phase of the output voltage of the flywheel ahead of the voltage on the power grid side, so as to achieve flywheel inertia output. When the power grid system fails, the flywheel can instantaneously supplement the active power shortage of the power system, realizes the frequency modulation function of the system through the compensation function, balances the disturbance of the power grid system, and keeps the voltage on the power grid side stable. That is, through the phase shifter, the output voltage can be made to lead, and then the flywheel has the function of inertia support, increases the inertia support function of the flywheel to the power grid, expands the market application, and realizes the maximum market value of the flywheel.

[0045] The power grid frequency modulation system comprises a distributed flywheel energy storage system and a phase shifter connected in sequence, and the phase shifter is connected to the power grid. The distributed flywheel energy storage system is used for outputting the voltage required by the power grid to the phase shifter. The phase shifter is used for adjusting the phase of the voltage and outputting the target voltage with a leading phase to the power grid to adjust the frequency of the power grid. Through the series connection of the phase shifter, the output voltage can be made to lead the voltage on the power grid side, achieve flywheel inertia output, increase the inertia support function of the flywheel to the power grid, and expand the market application.

[0046] According to different adjustment requirements, the distributed flywheel energy storage system 1 can comprise a single distributed flywheel energy storage unit 11 or a plurality of distributed flywheel energy storage units 11.

[0047] Specifically, in one possible implementation, referring to Figure 2 As shown in the figure, the distributed flywheel energy storage system 1 comprises a single distributed flywheel energy storage unit 11 connected in series to the phase shifter 2.

[0048] In another possible implementation, referring to Figure 3 As shown in the figure, the distributed flywheel energy storage system 1 comprises a plurality of distributed flywheel energy storage units 11 connected in parallel to the phase shifter 2.

[0049] In actual application process, if the energy required by the power grid adjustment is small, a single distributed flywheel energy storage unit can generally provide the required electric energy, but if the energy required by the power grid adjustment is large, a plurality of distributed flywheel energy storage units are generally required to realize the output of watt-level energy.

[0050] As a possible implementation, see Figure 4 As shown in FIG. 1, each distributed flywheel energy storage unit 11 includes a distributed flywheel energy storage device 111 and a power converter 112 connected in sequence: the power converter 112 is connected with the phase shifter 2; the distributed flywheel energy storage device 111 is used to output a second voltage to the power converter 112; the power converter 112 is used to convert the second voltage into a voltage required by the power grid 3 and output to the phase shifter 2.

[0051] The above-mentioned distributed flywheel energy storage device is mainly composed of a flywheel body, a bearing and a motor. When external work is done on the flywheel, the flywheel accelerates rotation, and the energy is stored in the form of kinetic energy. When energy needs to be released, the flywheel decelerates, and the kinetic energy is converted into electrical energy output.

[0052] The above-mentioned power converter is a device that converts electrical energy from one form to another. Common forms include alternating current (AC) to direct current (DC), direct current to alternating current, low voltage to high voltage, or high voltage to low voltage, etc. Power converters are widely used in power systems, electronic devices, industrial control, etc. Power converters usually have high conversion efficiency and stability, and can stably convert input electrical energy into output electrical energy, reducing energy loss. Specifically, the power converter can adjust the parameters of the output electrical energy, such as voltage, current, frequency, etc. according to needs.

[0053] The working principle of the power converter is based on the switching characteristics of power electronic devices. By controlling the switching time and frequency of the power switch, the adjustment and conversion of the input electrical energy can be realized.

[0054] In a possible implementation, the above-mentioned power converter can adopt a bidirectional power converter.

[0055] In a possible implementation, the above-mentioned phase shifter can adopt a synchronous phase shifter.

[0056] The synchronous phase shifter adjusts the phase of the signal by adjusting the position of the rotor, and is widely used in various fields that require precise phase control. Its working principle is based on electromagnetic induction principle. The synchronous phase shifter is usually used for signal processing that needs to be synchronized with a specific frequency. It can adjust the phase of the signal while keeping the frequency unchanged. The synchronous phase shifter is usually used in systems that require precise phase control. The synchronous phase shifter can ensure that the frequency and phase of the signal remain consistent, and is suitable for scenes that require high phase control.

[0057] In practical application, the distributed flywheel energy storage device has the advantages of fast response speed, high energy conversion efficiency, no pollution, etc. A high-power pulse power source can be generated through the distributed flywheel energy storage unit, and low-carbon zero-emission and environmental protection and energy saving can be realized in the power supply process. After the distributed flywheel energy storage device outputs the second voltage to the power converter, the power converter can adjust the voltage required by the power grid according to the demand of the output power, and then output to the phase shifter.

[0058] As a possible implementation, refer to Figure 5 As shown, the controller 4 is connected with the phase shifter 2, each power converter 112 and each distributed flywheel energy storage device 111 respectively.

[0059] In practical application, the controller can control each distributed flywheel energy storage device to discharge to output power to each corresponding power converter, control each power converter to convert the input power into the required power of the power grid and output to the phase shifter, and then control the phase shifter to adjust the phase of the corresponding voltage of the required power of the power grid, advance the phase, output the target voltage with advanced phase, that is, make the output voltage advanced, and then make the flywheel have the effect of inertia support.

[0060] As a possible implementation, refer to Figure 6 As shown, the system further comprises an acquisition unit 5 connected with the controller 4 and the power grid 3 respectively; the acquisition unit 5 is used to determine the frequency deviation of the power grid 3 and send the frequency deviation to the controller 4.

[0061] The frequency deviation of the power grid can be understood as the frequency fluctuation of the power grid. If the frequency deviation is large, it is considered that the frequency fluctuation of the power grid is large; if the frequency deviation is small, it is considered that the frequency fluctuation of the power grid is small.

[0062] In practical application, the acquisition unit sends the acquired frequency deviation of the power grid to the controller, and the controller can control the flywheel energy storage unit to charge or discharge (actually the controller can judge the frequency change direction to determine the working mode of the distributed flywheel energy storage device, such as charging or discharging), so as to realize accurate adjustment of the frequency deviation. Specifically, the controller can judge whether the frequency deviation is less than 0 (equivalent to judging the frequency change direction); if the frequency deviation is less than 0, the flywheel energy storage device is discharged until the frequency deviation is 0 and the change amount of the frequency deviation per unit time is 0; at this time, it is considered that the frequency of the power grid is stable, and there is no need to continue to adjust. By determining the frequency deviation and controlling the flywheel energy storage device accordingly, the accuracy of the control can be improved.

[0063] As a possible implementation, refer to Figure 7As shown in the figure, the acquisition unit 5 comprises a collection device 51, a filtering device 52 and an analysis device 53 connected in sequence; the collection device 51 is connected with the power grid 3, and the analysis device 53 is connected with the controller 4; the collection device 51 is used for collecting the voltage of the power grid 3; the filtering device 52 is used for filtering the voltage to obtain the required voltage of the power grid 3; and the analysis device 53 is used for frequency analysis on the required voltage of the power grid 3 to obtain the frequency deviation of the power grid 3 and send the frequency deviation to the controller 4.

[0064] The collection device can adopt a voltmeter, the filtering device can adopt a filter, and the analysis device can adopt a frequency analyzer.

[0065] In actual application, the voltage signal can be collected between the main transformer and the secondary transformer of the power grid, the voltage signal is filtered to obtain a voltage signal without or with less interference, and the filtered voltage signal is subjected to frequency analysis to obtain the frequency deviation of the power grid, so as to predict the frequency change direction of the power grid.

[0066] As a possible implementation, refer to Figure 8 As shown in the figure, each distributed flywheel energy storage device 111 comprises a motor 1111 and a flywheel body 1112 connected in sequence; each motor 1111 is connected with the controller 4 and the corresponding power converter 112 respectively.

[0067] The model of the distributed flywheel energy storage device can adopt Saturn 2-FW50160, and the rated power is 500kW. The application field of the distributed flywheel energy storage device of this model generally includes new energy primary frequency modulation, micro-grid frequency modulation and voltage regulation, hybrid energy storage frequency modulation and peak shaving, etc.

[0068] The motor can adopt a bidirectional motor. The process of generating electric energy by the flywheel is realized through the bidirectional motor. The mutual conversion and storage between electric energy and the mechanical energy of the high-speed flywheel.

[0069] As a possible implementation, refer to Figure 9 As shown in the figure, each power converter 112 comprises an input end 1121, a control circuit 1122, a power switch 1123 and an output end 1124; the input end 1121, the control circuit 1122 and the output end 1124 of each power converter 112 are connected in sequence, each input end 1121 is further connected with the corresponding motor 1111, each output end 1124 is further connected with the phase shifter 2, and each control circuit 1122 is further connected with the controller 4 and the corresponding power switch 1123.

[0070] The power converter mainly comprises an input end, an output end, a power switch and a control circuit.

[0071] In the implementation process, the input end can receive the power delivered by the motor; the output end can output the transformed power; the power switch is a switch for controlling the input power, which can generally switch the circuit according to different control signals, and common power switches include transistors, MOSFETs, IGBTs, etc.; the control circuit is used for controlling the working state of the power switch, which can generally control the switching time and frequency of the switch according to the characteristics of the input power and the demand of the output power. Specifically, the input end receives the power input by the electrode, the control circuit controls the switching state of the power switch according to the demand of the output power, so that it switches at a certain frequency, thereby realizing the adjustment and transformation of the input power. When the power switch is on, the power is transmitted to the output end; when the power switch is off, the power is isolated.

[0072] According to market needs and changes, auxiliary services for supporting the inertia of the power grid are needed, and there is no synchronous machine (SM) in series in the original system; the synchronous machine is adopted in series in the application, the inertia output of the flywheel is realized, the demand of the power grid auxiliary application is made up and supplemented, the overall cost can be reduced through the design, more market share can be obtained in the auxiliary service market, and specifically, the market demand can be met in high-precision power supply services and frequency modulation markets.

[0073] The above is only a demonstrative embodiment of the utility model, and is not used to limit the protection scope of the utility model, and the protection scope of the utility model is determined by the appended claims. The special term "demonstrative" means "as an example, embodiment or illustrative". Any embodiment explained as "demonstrative" is not necessarily interpreted as superior or better than other embodiments.

[0074] In addition, the terms "first", "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included one or more features. In the description of the disclosure, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0075] The above has described various embodiments of the disclosure, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles, practical applications or improvements of technology in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

[0076] Finally, it should be noted that: apparently, the above embodiments are merely examples for clearly illustrating the utility model, and are not limited to the implementation. For ordinary skilled persons in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and impossible to exhaust all the implementation. The obvious changes or variations derived therefrom are still within the protection scope of the utility model.

Claims

1. A power grid frequency regulation system characterized by, The application relates to a distributed flywheel energy storage system and a phase shifter connected in sequence, wherein the phase shifter is connected to a power grid. The distributed flywheel energy storage system is used to output a voltage required by the power grid to the phase shifter. The phase shifter is used to adjust the phase of the voltage and output a target voltage with a phase lead to the power grid to adjust the frequency of the power grid. The distributed flywheel energy storage system comprises at least one distributed flywheel energy storage unit, and a plurality of the distributed flywheel energy storage units are connected in parallel to the phase shifter.

2. The system of claim 1, wherein, Each distributed flywheel energy storage unit comprises a distributed flywheel energy storage device and a power converter connected in sequence, wherein the power converter is connected to the phase shifter.

3. The system of claim 2, wherein, The distributed flywheel energy storage device is used to output a second voltage to the power converter. The power converter is used to convert the second voltage into a voltage required by the power grid and output the voltage to the phase shifter. A controller is further included, which is connected to the phase shifter, each power converter and each distributed flywheel energy storage device respectively.

4. The system of claim 3, wherein, An acquisition unit is further included, which is connected to the controller and the power grid respectively.

5. The system of claim 4, wherein, The acquisition unit is used to determine the frequency deviation of the power grid and send the frequency deviation to the controller. The acquisition unit comprises a collection device, a filtering device and an analysis device connected in sequence, wherein the collection device is connected to the power grid and the analysis device is connected to the controller.

6. The system of claim 5, wherein, The collection device is used to collect the voltage of the power grid. The filtering device is used to filter the voltage to obtain a voltage required by the power grid. The analysis device is used to perform frequency analysis on the voltage required by the power grid to obtain the frequency deviation of the power grid and send the frequency deviation to the controller. Each distributed flywheel energy storage device comprises a motor and a flywheel body connected in sequence, wherein each motor is connected to the controller and the corresponding power converter respectively.

7. The system of claim 6, wherein, Each power converter comprises an input end, a control circuit, a power switch and an output end, wherein the input end, the control circuit and the output end of each power converter are connected in sequence, each input end is further connected to the corresponding motor, each output end is further connected to the phase shifter, and each control circuit is further connected to the controller and the corresponding power switch.

8. The system of claim 7, wherein, The phase shifter is a synchronous phase shifter.

9. The system of claim 1, wherein, The power converter is a bidirectional power converter.

10. The system of claim 3, wherein, ​

Images