CN113922400B - New energy support machine with energy storage device arranged through electrical connection and control method - Google Patents
New energy support machine with energy storage device arranged through electrical connection and control method Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/30—Arrangements for balancing of the load in a network by storage of energy using dynamo-electric machines coupled to flywheels
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
- H02J3/241—The oscillation concerning frequency
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/16—Mechanical energy storage, e.g. flywheels or pressurised fluids
Abstract
The invention discloses a new energy support machine with an energy storage device arranged through electrical connection and a control method thereof. This new forms of energy support machine includes: the system comprises a double-fed asynchronous motor, a direct-current exciter and an energy storage device; the rotor of the double-fed asynchronous motor is mechanically connected with the rotor of the direct-current exciter; the energy storage device includes: the inertia element is mechanically connected with a rotor of the synchronous motor; the stator of the dc exciter is electrically connected to the stator of the synchronous machine. The new energy support machine provided by the invention is provided with the direct-current exciter and the energy storage device in sequence from the rotor of the double-fed asynchronous motor in an electrical connection mode, inertia elements arranged in the energy storage device are effectively utilized to increase the inertia of the new energy support machine, and the inertia support capability of the new energy support machine to an alternating-current power grid is improved.
Description
Technical Field
The invention belongs to the technical field of operation and control of power systems, and particularly relates to a new energy support machine with an energy storage device arranged through electrical connection and a control method thereof.
Background
Under the condition that the permeability of new energy in China is higher and higher, the inertia support of the power system mainly depends on the inertia time constant of a conventional synchronous unit. Although the new energy unit can also provide certain inertia support for the system, the new energy unit is not popularized and used in a power grid at present. Moreover, when the frequency change rate is too high, the frequency change protection of the grid-connected new energy source unit acts, so that the new energy source unit is disconnected, and the frequency fluctuation condition of the system is further worsened.
The synchronous phase modulator is widely arranged in the extra-high voltage direct current converter station. When the frequency of a power grid is disturbed, the rotor of the synchronous phase modulator provides certain inertia support for the system, inhibits the rapid change of the frequency and strives for time for primary frequency modulation. However, the inertia support of the synchronous condenser is not controllable and cannot participate in the primary tuning task of the system.
Therefore, how to provide a fast and correct reactive response in the transient process of voltage jump on the premise of realizing the steady-state voltage regulation of the power system and adjust the inertia and primary frequency modulation of the power system is a problem to be solved urgently in the operation and control of the power system at present.
At present, a new energy support machine of an alternating current power grid is connected to a new energy station grid-connected point, and inertia support and primary frequency modulation capability provided for the alternating current power grid cannot meet the requirements of operation and control of a power system.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a new energy support machine, a system and a control method for arranging an energy storage device through electrical connection, so as to solve the problem that the inertia support capability provided by the existing new energy support machine for an alternating current power grid cannot meet the operation and control requirements of a power system.
In a first aspect, the present invention provides a new energy support machine with an energy storage device disposed through electrical connection, comprising: the system comprises a double-fed asynchronous motor, a direct-current exciter and an energy storage device; the rotor of the double-fed asynchronous motor is mechanically connected with the rotor of the direct-current exciter; the energy storage device includes: the inertia element is mechanically connected with a rotor of the synchronous motor; the stator of the dc exciter is electrically connected to the stator of the synchronous machine.
Further, the number of pole pairs of the direct current exciter is p2, and the number of pole pairs of the synchronous motor is p 3;
the rotating speed of the rotor of the double-fed asynchronous motor is N1At a rotational speed N of the rotor of the synchronous machinemComprises the following steps:
Nm= N1*p2/ p3。
further, still include: a machine side converter, a grid side converter; the rotor of the double-fed asynchronous motor is also electrically connected with the machine side converter; the stator of the double-fed asynchronous motor is electrically connected with the alternating current power grid; and the grid-side converter is electrically connected with the alternating current power grid and provides direct current voltage for the machine-side converter.
Further, when the rotating speed of the rotor of the doubly-fed asynchronous motor is increased, the rotating speed of the inertia element is increased, the rotational kinetic energy of the inertia element is increased, and the stator of the doubly-fed asynchronous motor absorbs active power from the alternating current power grid; when the rotating speed of the rotor of the double-fed asynchronous motor is reduced, the rotating speed of the inertia element is reduced, the rotational kinetic energy of the inertia element is reduced, and the stator of the double-fed asynchronous motor injects active power into the alternating current power grid.
Further, the inertia element is disposed within a vacuum chamber; and/or the inertia element is supported in rotation by a magnetic levitation system.
Further, the rotor of the dc exciter is made of a permanent magnet.
Further, still include: a main transformer; and the stator of the double-fed asynchronous motor is electrically connected with the alternating current power grid through the main transformer.
Further, still include: an excitation transformer; the grid-side converter is electrically connected with the alternating current power grid through the exciting transformer.
In a second aspect, the present invention provides a new energy support machine system, comprising: the new energy support machine of the first aspect; the system comprises a collecting device and an active control unit; when the new energy support machine executes a primary frequency modulation task, the acquisition device is used for acquiring the frequency of an alternating current power grid and the rotating speed of a rotor of a double-fed asynchronous motor of the new energy support machine, and the active control unit is used for generating an active power regulation instruction according to the frequency of the alternating current power grid and the rotating speed of the rotor of the double-fed asynchronous motor; and the machine side converter of the new energy support machine is used for responding to the active power regulation instruction, regulating the rotating speed of the rotor of the double-fed asynchronous motor and further regulating the frequency of the alternating current power grid.
In a third aspect, the present invention provides a control method of a new energy support machine, for controlling the new energy support machine according to the first aspect; the control method comprises the following steps: when a primary frequency modulation task is executed, generating an active power regulation instruction according to the acquired alternating current power grid frequency and the rotating speed of the rotor of the double-fed asynchronous motor of the new energy support machine; and sending the active power regulation instruction to the new energy support machine, so that the new energy support machine executes the active power regulation instruction to absorb active power from an alternating current power grid or inject active power into the alternating current power grid, and further regulate the frequency of the alternating current power grid.
The new energy support machine provided by the invention is provided with the direct-current exciter and the energy storage device in sequence from the rotor of the double-fed asynchronous motor in an electrical connection mode, inertia elements arranged on the energy storage device are effectively utilized to increase the inertia of the new energy support machine, and the inertia support capability of the new energy support machine to an alternating-current power grid is improved.
Different from a mechanical connection mode of gear transmission, the new energy support machine is provided with the energy storage device with the inertia element in an electrical connection mode, mechanical abrasion is reduced, and the service life and the reliability of the new energy support machine are integrally improved.
The new energy support machine has larger inertia support capacity, an alternating current power grid is connected to a new energy station grid-connected point, and the problem of frequency adjustment caused by insufficient inertia in a new energy collection area in the existing power system can be solved.
Drawings
A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:
fig. 1 is a schematic structural view of a new energy support machine according to a preferred embodiment of the present invention;
fig. 2 is a schematic view illustrating the composition and connection of a frequency converter of the new energy supporting machine according to the preferred embodiment of the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the invention and to fully convey the scope of the invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
The rotor described below includes both the machine body and the windings thereon. The stator described below includes both the machine body and the windings thereon.
For an alternating current grid system, a primary frequency modulation function is one of means for dynamically ensuring the active power balance of the grid. Specifically, the active power in the power grid is adjusted along with the change of the power grid frequency, so that the control of the power grid frequency is realized.
Specifically, a certain type of new energy support machine connected in parallel at a new energy grid connection point has two typical working modes:
1) when the grid frequency f>fnIn time, the new energy support machine as a whole absorbs active power from the ac grid, the speed N of the rotor of its doubly-fed asynchronous machinerIs increased by Nr>Nn. In this case, the double-fed asynchronous machine is operated in the super-synchronous motor mode, the stator-side power flow direction of which is from the ac power supply system into the double-fed asynchronous machine, where N isnIs the rated speed, f, of the rotor of the doubly-fed asynchronous machinen Is a rated value of the grid frequency.
2) When the grid frequency f<fnIn the meantime, the new energy supporting machine integrally releases active power to the power grid, and the rotating speed N of the rotor of the doubly-fed asynchronous motorrDecrease by Nr<Nn(ii) a In this case, the doubly-fed asynchronous machine is operated in a subsynchronous generator mode, the stator-side power flow of which is from the stator of the doubly-fed asynchronous machine into the ac grid.
That is, after the increase of the grid frequency is detected, the new energy support machine is put into use, and active power is quickly absorbed from the grid by the new energy support machine, so that the grid frequency can be quickly adjusted to fall within the safety range of the grid frequency deviation. Or after the reduction of the power grid frequency is detected, the new energy support machine is put into the power grid, and active power is quickly released into the power grid by the new energy support machine, so that the power grid frequency can be quickly adjusted to be increased to be within the safety range of the power grid frequency deviation, and the problem of frequency adjustment of a new energy convergence area in the existing power system due to insufficient inertia is solved.
In the above way, the new energy support machine utilizes the increase or decrease of the kinetic energy of the rotor by adjusting the rotating speed of the rotor of the doubly-fed asynchronous motor to quickly release active power into the power grid or quickly absorb the active power from the power grid so as to provide primary frequency modulation capability for the power grid.
However, the inertia of the rotor of the doubly-fed asynchronous motor in the new energy support machine is limited, the adjustable range of the rotating speed of the rotor is limited, and the inertia support requirement required by safe and efficient grid-connected operation of a new energy station is difficult to meet.
On the other hand, mechanical energy storage has a relatively wide application. The application forms of the mechanical energy storage comprise pumped storage, compressed air energy storage and rotational inertia energy storage. In general, the rotational inertia energy storage stores or releases energy by releasing or storing mechanical energy of an inertia element (generally, a cylinder made of a solid material, which is also called a flywheel because the rotational speed of the cylinder is generally high) rotating at a high speed, such as the rotational kinetic energy of the flywheel.
One possible approach is therefore to modify the rotor of a doubly-fed asynchronous machine such that it has a mechanical connection interface adapted to the gear drive and is connected to the flywheel by means of the gear drive. At this time, the rotation speed of the flywheel can be further increased by utilizing the large speed-increasing ratio of the gear transmission, so that the rotation kinetic energy of the flywheel can be further increased. However, the mechanical abrasion of gear transmission is large, the failure rate is high when the new energy supporting machine runs for a long time (such as 15-30 years), and the overall reliability of the new energy supporting machine is reduced by adopting the gear transmission in combination with the use scene that the new energy supporting machine needs to run for a long time.
As shown in fig. 1, the new energy support machine according to the embodiment of the present invention is used for accessing an ac grid at a new energy site grid-connected point, and includes: doubly-fed asynchronous machines, dc exciters, such as multi-pole dc exciters, energy storage devices, i.e. high-speed flywheel energy storage; the energy storage device includes: an inertia element, namely a flywheel, a synchronous machine, which is mechanically connected to the rotor of the synchronous machine; the rotor of the double-fed asynchronous motor is mechanically connected with the rotor of the direct-current exciter; the stator of the dc exciter is electrically connected to the stator of the synchronous machine.
The new energy support machine provided by the invention is provided with the direct-current exciter and the energy storage device in sequence from the rotor of the double-fed asynchronous motor in an electrical connection mode, inertia elements arranged in the energy storage device are effectively utilized to increase the inertia of the new energy support machine, and the inertia support capability of the new energy support machine to an alternating-current power grid is improved.
Different from a mechanical connection mode of gear transmission, the new energy support machine is provided with an energy storage device with larger inertia from a rotor of a double-fed asynchronous motor in an electrical connection mode, so that mechanical abrasion is reduced, and the service life and the reliability of the new energy support machine are integrally improved.
The new energy support machine has larger inertia support capacity, an alternating current power grid is connected to a new energy station grid-connected point, and the problem of frequency adjustment caused by insufficient inertia in a new energy collection area in the existing power system can be solved.
When the system is subjected to rapid frequency change due to unbalanced power, the new energy support machine inhibits the frequency change of the power system by injecting or absorbing active power into or from the power grid, and provides inertia support for the power system so as to increase the frequency regulation capacity of the new energy station.
When the new energy support machine obtains active power and energy from the alternating current power grid, the rotor of the double-fed asynchronous motor works at a rated rotating speed NnAnd the rotor of the direct current exciter is driven to rotate, and the rotating speed of the rotor is continuously increased. When the rotor of the direct current exciter works above the rated rotating speed, the direct current exciter is in a direct current generator state. The rotor magnetic pole of the dc exciter rotates to generate a rotating magnetic field. The stator of the dc exciter cuts the magnetic lines of force to generate ac power. The alternating current generated by the direct current exciter is connected into a stator of the synchronous motor. At this time, the rotor of the synchronous motor operates above the rated rotation speed, and the rotation speed is continuously increased, so that the synchronous motor is in a motor state. The rotor of the synchronous machine drives the inertia element mechanically connected thereto at a continuously increasing rotational speed, so that the energy taken by the new-energy-source support machine from the ac power grid is stored in such a way that the rotational kinetic energy of the inertia element increases.
When the new energy support machine releases active power and energy to the alternating current power grid, the rotating speed of the inertia element is below the rated rotating speed and is continuously reduced, and the energy is released in a mode that the rotating kinetic energy of the inertia element is reduced. At this time, the rotor of the synchronous motor operates below the rated rotation speed, and the rotation speed is continuously reduced, so that the synchronous motor is in a generator state. The alternating current generated by the stator of the synchronous machine is connected to the stator of the direct current exciter. The stator of the dc exciter takes ac power from the stator of the synchronous machine to which it is connected. The rotor magnetic pole of the dc exciter rotates to generate a rotating magnetic field. The rotor of the DC exciter works below the rated speed, and the DC exciter is in a DC motor state. At this time, the rotor of the direct current exciter drives the rotor of the doubly-fed asynchronous motor to rotate, and the rotating speed is continuously reduced.
In the above, the description of the actions of the inertia element, the synchronous motor, the dc exciter, and the doubly-fed asynchronous motor as the execution element in the typical scenario when the new energy support machine participates in the primary frequency modulation is described.
In the concrete implementation, the rotating speed of the rotor of the double-fed asynchronous motor is controlled by the frequency converter. The synchronous motor and the direct current exciter can also be provided with auxiliary elements for realizing control of excitation and the like, and the description is omitted.
As shown in fig. 1, the double-fed asynchronous machine provided with the new energy support machine comprises a stator (the active power absorbed or released by the stator is denoted as P)s) And rotor (active power absorbed or released by the rotor is recorded as Pr). During the response of the power system to an unbalanced power disturbance, the new energy support machine as a whole absorbs or injects electrical energy from or into the power system.
Specifically, new forms of energy supporting machine system includes new forms of energy supporting machine, controlling means, collection system. The control device comprises an active control unit, wherein the active control unit is used for generating an active power regulation instruction and controlling a machine side converter to execute the active power regulation instruction so as to enable a stator of the double-fed asynchronous motor to absorb active power and energy from a power grid and enable an energy storage device to store the active power and energy absorbed by the stator from the power grid by increasing rotating speed and kinetic energy; or the stator of the double-fed asynchronous motor releases active power and energy to the power grid, and the energy storage device releases the active power and energy provided to the power grid by reducing the rotating speed and kinetic energy.
As shown in fig. 1, the double-fed asynchronous machine is a wound-rotor asynchronous machine. The stator of the double-fed asynchronous motor is connected with the secondary side of the main transformer, and the primary side of the main transformer is connected with the alternating current power grid. In steady state operation, the current frequency of the stator of the doubly-fed asynchronous machine is the same as the frequency of the alternating current network.
In specific implementation, the rotor of the dc exciter is mechanically connected, for example, coaxially connected, for example, by a key (flat key or spline) or by a coupling, to the rotor of the doubly-fed asynchronous motor, so that the rotation speed of the rotor of the dc exciter is the same as the rotation speed of the rotor of the doubly-fed asynchronous motor, and there is no rotation speed difference between the two.
The stator of the synchronous machine is electrically connected (e.g., by a cable or copper bar) to the stator of the dc exciter, and thus the frequency of the rotating field of the stator of the synchronous machine is the same as the frequency of the rotating field of the stator of the dc exciter.
The rotational speed of the stator rotating field of the multi-pole dc exciter = rotor rotational speed x number of pole pairs of the multi-pole dc exciter. In particular embodiments, the excitation current of the multi-pole dc exciter may be generated by a dc voltage applied to the rotor by an external excitation power source; or may be produced by the rotor itself, which is made of permanent magnets. At the moment, the direct current exciter is a permanent magnet exciter, an exciting winding and a direct current exciting power supply are not needed, the structure is simple, and the operation is more reliable.
The direct-current exciter is simple in structure and low in cost, and provides a high-efficiency way for the energy exchange between the inertia elements and an alternating-current power grid by using the stored mechanical kinetic energy of the inertia elements.
As shown in fig. 1, the doubly-fed asynchronous machine is ac-excited with the stator windings on the outside and the rotor inside the stator windings. The double-fed asynchronous motor is horizontally installed; correspondingly, the direct current exciter is also horizontally installed. However, both the flywheel and the synchronous motor are vertically mounted, and for example, the flywheel with a larger radial size is positioned below the synchronous motor. The double-fed asynchronous motor adopts horizontal installation, is favorable for realizing dynamic balance, and reduces the manufacturing, installation and debugging cost.
Specifically, the number of pole pairs of the direct current exciter is p2, and the number of pole pairs of the synchronous motor is p 3; the rotating speed of the rotor of the double-fed asynchronous motor is N1At a speed of N of the rotor of the synchronous machinem:
Nm= N1*p2/ p3。
As shown in fig. 1, the energy storage device includes a flywheel and a synchronous motor as inertia elements. The flywheel is coaxially connected with the rotor of the synchronous motor, for example, through a key (flat key or spline) or through a coupling, and there is no difference in rotation speed between the flywheel and the rotor of the synchronous motor. The flywheel rotational speed is therefore in a fixed ratio to the rotational speed of the rotor of the doubly-fed asynchronous machine, i.e. has a fixed transmission ratio.
If the stator of the synchronous motor adopts a pair of pole pairs, namely p3= 1; of synchronous machinesRotational speed N of rotor and flywheelmComprises the following steps: n is a radical ofm= N1*p2。
Therefore, when the number of pole pairs of the dc exciter and the number of pole pairs of the synchronous machine are reasonably arranged, the rotational speed N of the rotor and the flywheel of the synchronous machinemIs the rotational speed N of the rotor of a doubly-fed asynchronous machine1If a larger rotational inertia is used in combination with a larger angular velocity, a larger mechanical energy storage, such as an energy level of several hundreds of KWh, can be achieved. In addition, it is also possible to provide a larger reserve of kinetic energy, i.e. a larger energy storage capacity, with a relatively small moment of inertia.
In the flywheel rotating at a high speed, a large amount of kinetic energy can be stored. When a primary frequency modulation task is responded, more kinetic energy can be released in a shorter time and injected into an alternating current power grid; or absorb active power from an alternating current power grid, and convert the active power into rotational kinetic energy to be stored.
In the above, the number of pole pairs of the direct-current exciter and the number of pole pairs of the synchronous motor are utilized, and the direct-current exciter and the synchronous motor are used as the transmission ratio changing module, so that the transmission ratio between the flywheel and the rotating speed of the rotor of the doubly-fed asynchronous motor can be flexibly adjusted. Compared with a gear transmission scheme, the mechanical friction is less, so that the operation efficiency is higher, and the operation reliability is higher.
In specific implementation, in order to reduce the weight of the flywheel and increase the radial dimension of the flywheel so as to increase the energy storage capacity of the energy storage device to the maximum extent, the flywheel can be made of carbon fiber materials so as to increase the structural strength and the rotational inertia of the flywheel.
In specific implementation, considering that the air resistance is relatively large when the high-speed flywheel runs, the vacuum chamber is arranged outside the high-speed flywheel, so that the high-speed flywheel runs in a vacuum environment to reduce air friction.
In particular, the magnetic suspension system may be arranged to take account of the friction loss of the high-speed flywheel, so that the high-speed flywheel is supported by the magnetic suspension system for rotation, thereby reducing the friction loss.
As shown in fig. 1, the new energy support machine includes a frequency converter. As shown in fig. 2, the frequency converter comprises a grid-side converter and a machine-side converter connected in sequence. The grid-side converter is an AC-DC link, and the machine-side converter is a DC-AC link. As shown in fig. 1, the machine-side converter is also connected to the rotor of the doubly-fed asynchronous machine, and the rotational speed of the rotor is changed by changing the excitation of the rotor.
Specifically, the grid-side converter and the machine-side converter are all fully-controlled converters. In the new energy support machine, a grid-side converter adopts constant direct-current voltage control and constant reactive power control; and the machine side converter adopts constant active power and constant reactive power for control. Control targets and control commands for specific direct voltage, reactive power and/or active power are generated by the control device.
The new energy support machine may further include a main transformer. The main transformer is used for transforming the voltage of the alternating current power grid to a voltage value matched with the stator of the double-fed asynchronous motor.
In specific implementation, in order to reduce the voltage level of the frequency converter, the new energy support machine can be further provided with an exciting transformer. Although the addition of the exciting transformer increases the procurement cost, the procurement cost of the frequency converter can be reduced by reducing the voltage level of the converter.
And recording the frequency f of the alternating current power grid. The rotating speed of a rotor of the doubly-fed asynchronous motor is recorded as N1Then its reduced frequency is f1. Note that the three-phase AC frequency connected to the machine side converter is f2Then, the following relationship exists: f = f1±f2。
As shown in fig. 1, the new energy support machine system further includes a collection device 1 and a collection device 2. The acquisition device 1 mainly acquires three-phase current voltage, three-phase alternating current, phase angle, frequency, active power, reactive power and other electric quantities of an alternating current power grid. The acquisition device 2 mainly acquires the rotating speed of the double-fed asynchronous motor, the multi-pole direct-current exciter and the high-speed flywheel, the three-phase voltage and current on the stator side, the active power, the reactive power, the phase angle and other electric quantities, the three-phase voltage and current on the rotor side, the active power, the reactive power, the phase angle, the angle of the rotor and the electric quantities of the converter direct-current side voltage and current and other electric quantities, and sends the electric quantities to the control device.
The control device comprises an active control unit. An active control unit of the control device generates an active power adjusting instruction according to the received primary frequency modulation instruction, and the frequency converter, such as a machine side converter, responds to the active power adjusting instruction to control the change of the rotating speed of a rotor of the double-fed asynchronous motor, so that the rotating speed of the direct-current exciter is changed, and further the rotating speed of the energy storage device is changed.
For example, after the energy storage device is started and reaches a steady state, the synchronous motor is maintained at a constant rotation speed, and waits for receiving a control signal for energy release or energy storage.
In the starting stage or the increased energy storage state, the external electric energy drives the synchronous motor to operate, the synchronous motor drives the flywheel to rotate in an accelerating mode, the flywheel stores the energy in the form of kinetic energy, the energy storage process of converting the electric energy into mechanical energy is completed, and the energy is stored in the flywheel rotating at a high speed.
When the energy storage capacity is reduced, namely energy is released, the flywheel rotating at high speed drives the synchronous motor to generate electricity, the generated electric energy is injected into an alternating current power grid through the direct current synchronous exciter and the double-fed asynchronous motor, and the energy release process from mechanical energy to electric energy conversion is completed.
In the above way, through the electric-magnetic field coupling, the flywheel and the synchronous motor do not need to be separately designed with a special control device, and the multi-pole direct-current exciter does not need to be separately designed with a special control device, so that the system complexity is reduced, and the reliability is improved. The new energy support machine adjusts inertia, active power and energy through the arrangement of the direct-current exciter and the energy storage device and through the rotation speed control of the rotor of the double-fed asynchronous motor, and further increases the inertia support capacity.
As shown in fig. 1, the new energy support machine according to the embodiment of the present application is configured to access an ac power grid at a grid-connected point of a new energy station (not shown in the figure), where the new energy station accesses the ac power grid at the grid-connected point.
During specific implementation, a plurality of new energy supporting machines can be arranged for a certain new energy station according to the inertia supporting requirement of the alternating current power grid.
The control method of the new energy support machine comprises the following steps: when a primary frequency modulation task is executed, an active power adjusting instruction is generated according to the obtained alternating current power grid frequency and the rotating speed of a rotor of the doubly-fed asynchronous motor, and a frequency converter executes the active power adjusting instruction, so that the new energy support machine absorbs active power from an alternating current power grid or injects the active power into the alternating current power grid, and the alternating current power grid frequency is adjusted. See CN111193273B and CN111262254B for detailed control methods.
The new energy support machine provides inertia support for a power grid, and increases the frequency adjustment capacity of the new energy station. When the frequency of the power grid is changed rapidly due to unbalanced power, the support machine can provide inertia support capability and frequency adjustment capability for the power grid rapidly, stably and accurately.
After the new energy support machine is arranged on an electric power system, the forward regulation effect is generated on the frequency of an electric power grid, the phenomenon that the electric power system carries out load shedding protection action or generator tripping protection action due to sudden rising or sudden falling of the frequency is avoided, the phenomenon that a new energy station is disconnected from a network or an electric load is disconnected from the network is avoided, and the operation stability and the economical efficiency of a high new energy permeability electric network can be effectively improved.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The invention has been described above by reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a// the [ device, component, etc ]" are to be interpreted openly as at least one instance of a device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
Claims (10)
1. The utility model provides a set up energy memory's new forms of energy support machine through electrical connection which characterized in that includes:
the double-fed asynchronous motor, the direct current exciter and the energy storage device;
the rotor of the double-fed asynchronous motor is mechanically connected with the rotor of the direct-current exciter;
the energy storage device includes: the inertia element is mechanically connected with a rotor of the synchronous motor;
the stator of the dc exciter is electrically connected to the stator of the synchronous machine.
2. The new energy support machine of claim 1,
the number of pole pairs of the direct current exciter is p2, and the number of pole pairs of the synchronous motor is p 3;
the rotating speed of the rotor of the double-fed asynchronous motor is N1At a rotational speed N of the rotor of the synchronous machinemComprises the following steps:
Nm= N1*p2/ p3。
3. the new energy support machine of claim 2,
further comprising: a machine side converter and a grid side converter;
the rotor of the double-fed asynchronous motor is also electrically connected with the machine side converter;
the stator of the double-fed asynchronous motor is electrically connected with an alternating current power grid;
the grid-side converter is electrically connected with an alternating current power grid and provides direct current voltage for the machine-side converter.
4. The new energy support machine of claim 3,
when the rotating speed of a rotor of the doubly-fed asynchronous motor is increased, the rotating speed of the inertia element is increased, the rotational kinetic energy of the inertia element is increased, and a stator of the doubly-fed asynchronous motor absorbs active power from the alternating current power grid;
when the rotating speed of the rotor of the double-fed asynchronous motor is reduced, the rotating speed of the inertia element is reduced, the rotational kinetic energy of the inertia element is reduced, and the stator of the double-fed asynchronous motor injects active power into the alternating current power grid.
5. The new energy support machine according to any one of claims 1 to 4,
the inertia element is arranged in the vacuum chamber; and/or
The inertia element is supported for rotation by a magnetic levitation system.
6. The new energy support machine according to any one of claims 1 to 4,
the rotor of the direct current exciter is made of permanent magnets.
7. The new energy support machine according to any one of claims 1 to 4,
further comprising: a main transformer;
and the stator of the double-fed asynchronous motor is electrically connected with an alternating current power grid through the main transformer.
8. The new energy support machine of claim 3,
further comprising: an excitation transformer;
and the grid-side converter is electrically connected with an alternating current power grid through the exciting transformer.
9. The utility model provides a new forms of energy support machine system which characterized in that includes:
the new energy support machine of any one of claims 1 to 8;
the system comprises a collecting device and an active control unit;
when the new energy support machine executes a primary frequency modulation task, the acquisition device is used for acquiring the frequency of an alternating current power grid and the rotating speed of a rotor of a double-fed asynchronous motor of the new energy support machine,
the active control unit is used for generating an active power regulation instruction according to the alternating current power grid frequency and the rotating speed of the rotor of the double-fed asynchronous motor;
and the machine side converter of the new energy support machine is used for responding to the active power regulation instruction, regulating the rotating speed of the rotor of the double-fed asynchronous motor and further regulating the frequency of the alternating current power grid.
10. A control method of a new energy supporting machine, characterized by controlling the new energy supporting machine according to any one of claims 1 to 8; the control method comprises the following steps:
when a primary frequency modulation task is executed, generating an active power regulation instruction according to the acquired alternating current power grid frequency and the rotating speed of the rotor of the double-fed asynchronous motor of the new energy support machine;
and sending the active power regulation instruction to the new energy support machine, so that the new energy support machine executes the active power regulation instruction to absorb active power from an alternating current power grid or inject active power into the alternating current power grid, and further regulate the frequency of the alternating current power grid.
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| DE102018204787A1 (en) * | 2018-03-28 | 2019-10-02 | Siemens Aktiengesellschaft | Double-fed asynchronous machine with flywheel as phase shifter and energy storage |
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| EP2154769A1 (en) * | 2008-08-11 | 2010-02-17 | Siemens Aktiengesellschaft | Device for supplying power to a system |
| CN112910015A (en) * | 2021-01-18 | 2021-06-04 | 哈尔滨工业大学 | Permanent magnet excitation active and reactive power control system |
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Application publication date: 20220111 Assignee: NARI TECHNOLOGY Co.,Ltd. Assignor: CHINA ELECTRIC POWER RESEARCH INSTITUTE Co.,Ltd. Contract record no.: X2024980001768 Denomination of invention: New energy support machine and control method for setting up energy storage devices through electrical connections Granted publication date: 20220211 License type: Common License Record date: 20240131 |