CN219717894U - Integrated energy storage matrix type modularized multi-level converter - Google Patents
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Abstract
The utility model provides an integrated energy storage type matrix modular multilevel converter, relates to the technical field of power generation, and is used for solving the technical problems of large electric energy loss and large fluctuation of output power of a wind turbine generator. The integrated energy storage type matrix type modularized multi-level converter is connected between a generator of the fan and the boost transformer, alternating current output by the generator is of a first frequency, alternating current output by the boost transformer is of a second frequency, and the integrated energy storage type matrix type modularized multi-level converter converts the first frequency and the second frequency; the integrated energy storage type matrix modularized multi-level converter comprises a plurality of bridge arms, each bridge arm comprises a bridge arm reactor and a plurality of submodules which are connected in series, and each submodule comprises at least one energy storage battery pack. The integrated energy storage matrix type modularized multi-level converter directly performs alternating current-alternating current conversion, and reduces electric energy loss. The energy storage battery pack stores and releases electric energy, so that fluctuation of output power of the wind turbine generator can be reduced, and deviation of wind power prediction is made up.
Description
Technical Field
The utility model relates to the field of wind power generation, in particular to an integrated energy storage type matrix modular multilevel converter.
Background
Along with the increasing severity of environmental problems and energy problems, wind energy is taken as a renewable green resource, and is increasingly valued, and the power generation technology is continuously developed. In the process of power generation, electric energy generated by a generator of a fan is generally converted by a fan converter, boosted by a booster transformer and then output to a power grid. The fan converter adapts to different main shaft rotating speeds of the generator according to the wind speed, so that the generator captures the maximum wind energy, converts the electric energy generated by the generator under the action of natural wind into electric energy meeting the grid-connected requirement, and has certain fault crossing capability. However, in the above process, the electric energy loss of the fan converter is large, and the fluctuation of the output power of the wind turbine generator is large.
Disclosure of Invention
In view of the above problems, the embodiment of the utility model provides an integrated energy storage type matrix modular multilevel converter, which reduces electric energy loss and reduces fluctuation of output power of a wind turbine generator.
In order to achieve the above object, the embodiment of the present utility model provides the following technical solutions:
the embodiment of the utility model provides an integrated energy storage matrix type modularized multi-level converter, which is connected between a generator of a fan and a power grid, wherein the frequency of alternating current output by the generator is a first frequency, the frequency of alternating current output by a step-up transformer is a second frequency, and the integrated energy storage matrix type modularized multi-level converter is used for converting the first frequency and the second frequency;
the integrated energy storage matrix type modularized multi-level converter comprises a plurality of bridge arms, each bridge arm comprises a bridge arm reactor and a plurality of submodules which are connected in series, and each submodule comprises at least one energy storage battery pack.
In some possible embodiments, the bridge arm reactors are inductors.
In some possible embodiments, the plurality of sub-modules further each comprise: two first branches, a capacitor and a direct current port;
the two first branches and the capacitor are connected in parallel, the two ends of the two first branches and the two ends of the capacitor are respectively connected with the two direct current output ends of the direct current port, and the two ends of at least one energy storage battery pack are respectively connected with the two direct current input ends of the direct current port;
each first branch comprises two switching devices connected in series, and each switching device comprises a fully-controlled power electronic switch and a diode which are connected in parallel;
one of the energy storage battery packs includes a plurality of energy storage cells connected in series.
In some possible embodiments, the fully controlled power electronic switch is an insulated gate bipolar transistor or an integrated gate commutated thyristor;
when the fully-controlled power electronic switch is an insulated gate bipolar transistor, the collector of the insulated gate bipolar transistor is connected with the cathode of the corresponding diode, the emitter of the insulated gate bipolar transistor is connected with the anode of the corresponding diode, and the grid of the insulated gate bipolar transistor is connected with a peripheral circuit;
when the fully-controlled power electronic switch is an integrated gate commutated thyristor, the cathode of the integrated gate commutated thyristor is connected with the anode of the corresponding diode, the anode of the integrated gate commutated thyristor is connected with the cathode of the corresponding diode, and the gate of the integrated gate commutated thyristor is connected with a peripheral circuit.
In some possible embodiments, the generator is a doubly fed asynchronous generator, and the direct current port is a DC-DC transformer that controls charging and discharging of the corresponding energy storage battery pack.
In some possible embodiments, one end of the integrated energy storage matrix modular multilevel converter is connected to the rotor of the doubly fed asynchronous generator, and the other end is connected to the low voltage side of the step-up transformer.
In some possible embodiments, the generator is a permanent magnet generator, the dc port is a dc filter, and the capacitor controls charging and discharging of the corresponding energy storage battery pack.
In some possible embodiments, one end of the integrated energy storage matrix modular multilevel converter is connected to the stator of the permanent magnet generator, and the other end is connected to the low voltage side of the step-up transformer.
In some possible embodiments, the integrated energy storage matrix modular multilevel converter further comprises three first connection lines and three second connection lines, wherein one ends of the three first connection lines are all connected with the generator, and one ends of the three second connection lines are all connected with the low-voltage side of the step-up transformer;
the number of the bridge arms is nine, the nine bridge arms are distributed in three rows and three columns, the first ends of the three bridge arms in the same column are connected to one first connecting line, and the second ends of the three bridge arms in the same row are connected to one second connecting line.
In some possible embodiments, three of the first connection lines are respectively connected to three-phase outputs of the generator, and three of the second connection lines are respectively connected to three-phase inputs connected to the step-up transformer.
In the embodiment of the utility model, the integrated energy storage matrix type modularized multi-level converter is connected between the generator and the step-up transformer, the frequency of alternating current output by the generator is a first frequency, and the frequency of alternating current output by the step-up transformer is a second frequency so as to be transmitted to the power grid, and the integrated energy storage matrix type modularized multi-level converter is used for converting the first frequency and the second frequency, so that alternating current-alternating current conversion is directly carried out between the generator and the power grid, the conversion times of electric energy are reduced, and the loss of electric energy is reduced. The sub-module of the integrated energy storage matrix type modularized multi-level converter comprises at least one energy storage battery pack, and the energy storage battery pack is used for storing and releasing electric energy through the integrated energy storage battery pack, so that fluctuation of output power of the wind turbine generator can be reduced, fluctuation of input power to a power grid is reduced, deviation of wind power prediction can be compensated, and even the capacity of primary frequency modulation and even secondary frequency modulation is achieved.
In addition to the technical problems, technical features constituting the technical solutions, and beneficial effects brought by the technical features of the technical solutions described above, other technical problems that the integrated energy storage matrix-type modular multilevel converter provided by the embodiment of the present utility model can solve, other technical features included in the technical solutions, and beneficial effects brought by the technical features, further detailed description will be made in specific embodiments.
Drawings
In order to more clearly illustrate the embodiments of the present utility model or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an integrated energy storage matrix modular multilevel converter according to an embodiment of the present utility model;
FIG. 2 is a schematic diagram of a sub-module according to an embodiment of the present utility model;
fig. 3 is a schematic connection diagram of an integrated energy storage matrix modular multilevel converter according to an embodiment of the utility model;
fig. 4 is a schematic diagram illustrating another connection of an integrated energy storage matrix-type modular multilevel converter according to an embodiment of the utility model.
Reference numerals illustrate:
10-an integrated energy storage matrix type modularized multi-level converter;
11-bridge arms;
12-a first connection line;
13-a second connection line;
20-submodules;
21-a first branch;
22-a capacitor;
23-direct current port;
24-an energy storage battery;
25-a third connecting line;
26-fourth connecting lines;
27-a fifth connecting line;
28-a sixth connecting line;
30-a stator;
40-rotor;
50-step-up transformer.
Detailed Description
In the related art, the problems of larger electric energy loss and larger fluctuation of the output power of the wind turbine generator are solved, and the inventor researches find that the reason is as follows: a fan converter is arranged between the generator and the step-up transformer and comprises a machine side converter and a grid side converter which are connected through a direct current bus. After the electric energy of the generator is converted from alternating current to direct current to alternating current, the alternating current frequency of the generator is converted into the alternating current frequency of the power grid, and the alternating current frequency is boosted by a boosting transformer and is input into the power grid. The two conversions of electrical energy result in a larger loss of electrical energy from the generator, i.e., a larger loss of electrical energy, and the greater the electrical energy lost as the capacity of the generator is greater.
Meanwhile, the power generated by the fan converter is determined by wind energy captured by the generator, so that the fluctuation is larger, the randomness is also larger, the fluctuation of the output power of the wind turbine generator is larger, and the fluctuation of the power input into the power grid is larger. Wind power prediction is difficult to be completely accurate, and the traditional fan converter is not beneficial to peak regulation and frequency modulation of a power grid, so that installed quantity and generated energy are affected. The traditional fan converter is generally of a two-level or three-level topological structure, capacity is improved through parallel connection of a plurality of switching devices, the fan converter is easy to stop due to faults of a single switching device, and reliability is low.
In addition, when the capacity of the generator is large, two or more fan converters are often connected in parallel, and the connection complexity is further increased. The capacity is improved by increasing the current no matter the switching devices are connected in parallel or the fan converters are connected in parallel, and the loss in the transmission and conversion processes of electric energy is high.
Therefore, the embodiment of the utility model provides the integrated energy storage matrix type modularized multi-level converter which directly performs alternating current-alternating current conversion on the electric energy of the generator, so that the conversion times of the electric energy are reduced, and the loss of the electric energy is reduced. The integrated energy storage type matrix modularized multi-level converter is integrated with the energy storage battery pack, and the fluctuation of the output power of the wind turbine generator can be reduced by storing and releasing electric energy through the energy storage battery pack, so that the fluctuation of the input power to a power grid is reduced, and the deviation of wind power prediction is made up.
In order to make the above objects, features and advantages of the embodiments of the present utility model more comprehensible, the technical solutions of the embodiments of the present utility model will be described clearly and completely with reference to the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Referring to fig. 1 to 4, an embodiment of the present utility model provides an integrated energy storage matrix-type modular multilevel converter 10, wherein the integrated energy storage matrix-type modular multilevel converter 10 is connected between a generator of a fan and a step-up transformer 50. The frequency of the alternating current output by the generator is a first frequency, and the frequency of the alternating current output by the step-up transformer 50 is a second frequency. The integrated energy storage matrix type modular multilevel converter 10 is used for converting the first frequency and the second frequency, converting the first frequency of alternating current of the generator into the second frequency, and outputting the second frequency to a power grid through the step-up transformer 50 for use by a power supply network. Direct conversion of alternating current-alternating current is achieved through the integrated energy storage type matrix type modularized multi-level converter 10, and loss of electric energy is reduced.
The generator may be a generator with all output power connected to the grid through the integrated energy storage matrix modular multilevel converter 10, for example, a permanent magnet generator (including direct drive type, semi-direct drive type, etc.); it may also be a generator in which part of the output power is grid-connected via an integrated energy storage matrix modular multilevel converter 10, such as a doubly-fed asynchronous generator.
Referring to fig. 1 and 2, an integrated energy storage matrix modular multilevel converter 10 comprises a plurality of legs 11, for example 9 legs 11. Each bridge arm 11 comprises a bridge arm reactor and a plurality of sub-modules 20, the bridge arm reactor and the plurality of sub-modules 20 being connected in series.
The bridge arm reactor can be an inductance L so as to avoid the through short circuit fault of the bridge arm 11, thereby avoiding the sub-module 20 from being subjected to excessive current and ensuring the sub-module 20 to work normally. The number of sub-modules 20 is two or more, each sub-module 20 comprising at least one energy storage battery 24, the energy storage battery 24 storing and releasing electrical energy.
By arranging the energy storage battery pack 24 in the submodule 20, thereby integrating the energy storage battery pack 24 in the integrated energy storage matrix type modularized multi-level converter 10, the influence of power fluctuation of the generator on a power grid can be reduced by utilizing the energy storage battery pack 24 to store and release electric energy, deviation of wind power prediction is compensated, and even the capacity of primary frequency modulation and secondary frequency modulation is realized.
With continued reference to fig. 1 and 2, each sub-module 20 further comprises two first branches 21, a capacitor 22 and a dc port 23, i.e. the sub-module 20 is a full bridge sub-module (SM). Each first branch 21 comprises two switching devices connected in series, each switching device comprising a fully controlled power electronic switch and a diode connected in parallel. The fully controlled power electrons are shown as T1, T2, T3, T4 in fig. 2, and the diodes are shown as D1, D2, D3, D4 in fig. 2.
In some examples, the fully-controlled power electronic switch is an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor), abbreviated as IGBT), which is connected in reverse with the diode. In other examples, the fully controlled power electronic switch is an integrated gate commutated thyristor (Intergrated Gate Commutated Thyristor, IGCT for short) that is connected in reverse with the diode.
Specifically, when the fully-controlled power electronic switch is an insulated gate bipolar transistor, the collector of the insulated gate bipolar transistor is connected with the cathode of the corresponding diode, the emitter of the insulated gate bipolar transistor is connected with the anode of the corresponding diode, and the gate of the insulated gate bipolar transistor is connected with the peripheral circuit. The collector of one insulated gate bipolar transistor in the same first branch 21 is also connected to the emitter of the other insulated gate bipolar transistor and is commonly connected to an external conductor.
As illustrated in fig. 2, two insulated gate bipolar transistors in the first branch 21 are defined as a first transistor T1 and a second transistor T2, respectively, a diode corresponding to the first transistor T1 is defined as a first diode D1, and a diode corresponding to the second transistor T2 is defined as a second diode D2.
The collector of the first transistor T1 is connected with the cathode of the first diode D1, and the emitter of the first transistor T1 is connected with the anode of the first diode D1; the collector of the second transistor T2 is connected with the cathode of the second diode D2, and the emitter of the second transistor T2 is connected with the anode of the second diode D2; the first transistor T1 and the second transistor T2 are connected in series, namely, the collector of the first transistor T1 is also connected with the emitter of the second transistor T2, and an external lead is also connected between the first transistor T1 and the second transistor T2.
When the full-control power electronic switch is an integrated gate commutated thyristor, the cathode of the integrated gate commutated thyristor is connected with the anode of the corresponding diode, the anode of the integrated gate commutated thyristor is connected with the cathode of the corresponding diode, and the gate of the integrated gate commutated thyristor is connected with the peripheral circuit.
With continued reference to fig. 2, the two first branches 21 and the capacitor 22 are connected in parallel, and two ends of the two first branches 21 and the capacitor 22 are respectively connected to two dc output ends of the dc port 23. For example, after the two first branches 21 and the capacitor 22 are connected in parallel, one end of the two first branches 21 and one end of the capacitor 22 are connected to one dc output terminal of the dc port 23 via the third connection line 25, and the other end of the two first branches 21 and the other end of the capacitor 22 are connected to the other dc output terminal of the dc port 23 via the fourth connection line 26.
Two dc input terminals of the dc port 23 are respectively connected to two ends of at least one energy storage battery 24, and one energy storage battery 24 includes a plurality of energy storage batteries connected in series. When the number of the energy storage battery packs 24 is one, two ends of the energy storage battery packs 24 are respectively connected with two direct current input ends of the direct current ports 23; when the number of the energy storage battery packs 24 is greater than one, the energy storage battery packs 24 are connected in parallel, and both ends thereof are connected with two dc input ends of the dc port 23, respectively. For example, after the plurality of energy storage battery packs 24 are connected in parallel, one end of the plurality of energy storage battery packs 24 is connected to one dc input terminal of the dc port 23 via a fifth connection line 27, and the other end of the plurality of energy storage battery packs 24 is connected to the other dc input terminal of the dc port 23 via a sixth connection line 28.
The dc input and dc output of the dc port 23 are connected to the energy storage battery 24 and the capacitor 22, respectively, and charge and discharge of the energy storage battery 24 can be controlled by the dc port 23 or the capacitor 22 to store or release electric energy. On the one hand, when the generator is started, the energy storage battery pack 24 is utilized for starting, no waiting for reverse power transmission is needed, and a black start strategy can be adopted to be matched with other traditional fans, so that a grid-structured wind power plant is constructed. On the other hand, the scale of the energy storage power station matched with the wind power plant can be reduced, and even the matched energy storage power station is not built, so that the cost of the wind power plant is reduced. In addition, when the real-time electricity price is high, the wind farm can actively release the electric energy of the energy storage battery pack 24, send out the maximum power corresponding to the current wind speed, even exceed the rated power of the generator in a certain time, participate in spot market trading, and improve the economic benefit.
In some possible embodiments, the generator is a doubly-fed asynchronous generator (Double-Fed Induction Generator, DFIG for short), the DC port 23 is a DC-DC transformer, and the DC-DC transformer controls charging and discharging of the corresponding energy storage battery 24. Meanwhile, the DC-DC transformer also controls the voltage of the capacitor 22, and the voltage of the capacitor 22 can be accurately controlled at a set value. Referring to fig. 3, one end of the integrated energy storage matrix type modular multilevel converter 10 is connected to a rotor 40 of a doubly fed asynchronous generator, the other end is connected to a low voltage side of a step-up transformer 50, and a high voltage side of the step-up transformer 50 is connected to a power grid.
In other possible embodiments, the generator is a permanent magnet generator, the dc port 23 is a dc filter, and the capacitor 22 (e.g. its voltage) controls the charging and discharging of the corresponding energy storage battery 24, and the voltage value of the capacitor 22 is controlled within a certain range. Referring to fig. 4, one end of the integrated energy storage matrix type modular multilevel converter 10 is connected to the stator 30 of the permanent magnet generator, the other end is connected to the low voltage side of the step-up transformer 50, and the high voltage side of the step-up transformer 50 is connected to the power grid.
In the two embodiments, the integrated energy storage matrix type modular multilevel converter 10 can realize the conversion of alternating current within a certain range, so that the step-up transformer 50 can be not configured with a tap switch, the cost is reduced, and the probability of faults is reduced.
With continued reference to fig. 1, the number of bridge arms 11 in the integrated energy storage matrix type modular multilevel converter 10 is nine, the nine bridge arms 11 are arranged in three rows and three columns, that is, the nine bridge arms 11 are arranged in a matrix, the capacity of the integrated energy storage matrix type modular multilevel converter 10 can be greater than the capacity of a generator, the maximum design capacity thereof takes the discharge power of the energy storage battery pack 24 into consideration, and the input power of the power grid is greater than the output power of the generator.
The integrated energy storage matrix modular multilevel converter 10 further comprises three first connecting lines 12 and three second connecting lines 13, wherein one ends of the three first connecting lines 12 are connected with a generator, one ends of the three second connecting lines 13 are connected with a power grid through a step-up transformer 50, specifically, one ends of the three second connecting lines 13 are connected with a low-voltage side of the step-up transformer 50, and a high-voltage side of the step-up transformer 50 is connected with the power grid.
The integrated energy storage type matrix type modularized multi-level converter 10 is provided with 6 connecting ends, three connecting ends are connected with a generator and output alternating current of a first frequency, and the three connecting ends are the generator side of the integrated energy storage type matrix type modularized multi-level converter 10; the other three connecting ends are connected with the power grid and output alternating current of a second frequency, and the three connecting ends are the generator side of the integrated energy storage type matrix type modularized multi-level converter 10. Each first connecting line 12 is further connected to first ends of three bridge arms 11 in the same column, and each second connecting line 13 is further connected to second ends of three bridge arms 11 in the same row.
Specifically, as shown in fig. 1, the first connection line 12 is sequentially connected to the first end of the bridge arm 11 of the first row and the first column, the first end of the bridge arm 11 of the second row and the first column, and the first end of the bridge arm 11 of the third row and the first column. The second ends of the bridge arms 11 of the first row and the first column are connected to a first second connection line 13, the second ends of the bridge arms 11 of the second row and the first column are connected to a second connection line 13, and the second ends of the bridge arms 11 of the third row and the first column are connected to a third second connection line 13.
The second first connection line 12 is sequentially connected to the first end of the bridge arm 11 of the first row and the second column, the first end of the bridge arm 11 of the second row and the second column, and the first end of the bridge arm 11 of the third row and the second column. The second ends of the bridge arms 11 of the first row and the second column are connected to a first second connection line 13, the second ends of the bridge arms 11 of the second row and the second column are connected to a second connection line 13, and the second ends of the bridge arms 11 of the third row and the second column are connected to a third second connection line 13.
The third first connection line 12 is sequentially connected to the first end of the bridge arm 11 of the third column of the first row, the first end of the bridge arm 11 of the third column of the second row, and the first end of the bridge arm 11 of the third column of the third row. The second ends of the bridge arms 11 of the first row and the third column are connected to a first second connection line 13, the second ends of the second branches of the second row and the third column are connected to a second connection line 13, and the second ends of the bridge arms 11 of the third row and the third column are connected to a third second connection line 13.
In some examples, three first connection lines 12 are each connected to a three-phase output of the generator and three second connection lines 13 are each connected to a three-phase input of the connection grid. As shown in fig. 1, the three first connection lines 12 and the connection ends of the generator are respectively an a connection end, a b connection end and a c connection end, the a connection end, the b connection end and the c connection end are respectively connected with the three-phase output of the generator, and the a connection end, the b connection end and the c connection end output alternating current of a first frequency. The three second connecting wires 13 are respectively connected with the connecting ends of the power grid, namely an A connecting end, a B connecting end and a C connecting end, wherein the A connecting end, the B connecting end and the C connecting end are respectively connected with the three-phase input of the power grid, and the A connecting end, the B connecting end and the C connecting end output alternating current with second frequency.
In the embodiment of the present utility model, the integrated energy storage matrix modular multilevel converter 10 has three control targets, namely a target 1, a target 2 and a target 3. Target 1 is to send active power for the generator according to a maximum power point tracking (Maximum Power Point Tracking, abbreviated as MPPT) curve. The target 2 is to output active power of the generator according to a wind power prediction curve; or active power is sent out according to a primary frequency modulation curve or instruction. Target 3 is that the voltage of capacitor 22 in submodule 20 is kept within a certain range.
The three control targets generally adopt different control strategies and are coordinated with each other, so that the generator captures wind energy according to a Maximum Power Point Tracking (MPPT) curve and outputs active power according to a wind power prediction curve within the allowable range of the charge and discharge power and capacity of the energy storage battery pack 24. Specifically, the coordinated control strategy is:
1) The target 1 is realized by torque control or excitation control through one end (generator side) of the integrated energy storage matrix type modularized multi-level converter 10 connected with the generator, so that the generator outputs the corresponding maximum power at the current wind speed.
2) The object 2 is achieved by the integrated energy storage matrix modular multilevel converter 10 being connected to one end of the grid (grid side) by using fixed active power control. And for the permanent magnet generator, the active power command is consistent with the wind power prediction curve, and when the active power command needs to participate in grid frequency modulation, the active power command is switched into the grid frequency modulation power command. For a doubly-fed asynchronous generator, the active power command value subtracts the input power of the generator side of the integrated energy storage matrix modular multilevel converter 10 on the basis of a wind power prediction curve or a grid frequency modulation power command.
3) The implementation of the objective 3 varies depending on the manner in which the energy storage battery 24 is accessed. When the energy storage battery 24 is connected through a DC-DC transformer, i.e. the direct current port 23 is a DC-DC transformer, the target 3 is controlled by the DC-DC transformer, which can be precisely controlled at a set value. When the energy storage battery 24 is connected through the dc filter, that is, when the dc port 23 is the dc filter, the target 3 is determined by the electric quantity (State of Charge, SOC) of the energy storage battery 24, which fluctuates within a certain range.
It should be noted that the above control strategy is effective when the voltage of the capacitor in the submodule 20 and the charge/discharge power of the energy storage battery 24 are within a preset range, and when at least one of the two is not within the preset range, the control strategy needs to be switched. Specifically, when the voltage of the capacitor in the sub-module 20 exceeds the rated value in the preset range, or the maximum charge-discharge power of the energy storage battery pack 24 in the current remaining amount is smaller than the rated value in the preset range, the control target 2 is not used as the control target any more, the control strategy of the power grid side of the integrated energy storage matrix type modular multilevel converter 10 is switched to the voltage control strategy of the capacitor 22 in the stator module, and the switching mode can send a control strategy switching instruction through a higher-layer controller, or can be automatically switched through a voltage margin control strategy.
In some examples, the generator is a doubly-fed asynchronous generator, and the generator side of the integrated energy storage matrix modular multilevel converter 10 performs excitation control on the generator according to an MPPT curve; the power grid side of the integrated energy storage matrix type modularized multi-level converter 10 adopts fixed active power control, and the power command value is from a power prediction curve of the generator sent by a wind power prediction system, so that real-time active power sent by a generator stator 30 is subtracted.
In other examples, the generator is a permanent magnet generator, and the generator side of the integrated energy storage matrix modular multilevel converter 10 performs torque control on the generator according to an MPPT curve; the power grid side of the integrated energy storage matrix type modularized multi-level converter 10 adopts fixed active power control, and the power command value is from a power prediction curve of the generator sent by a wind power prediction system.
In summary, in the embodiment of the present utility model, the integrated energy-storage matrix-type modular multilevel converter 10 is connected between the generator and the step-up transformer, the frequency of the alternating current output by the generator is a first frequency, the frequency of the alternating current output by the step-up transformer to the power grid is a second frequency, and the integrated energy-storage matrix-type modular multilevel converter 10 is used for converting the first frequency and the second frequency, so that the alternating current-alternating current conversion is directly performed between the generator and the power grid, the conversion times of the electric energy are reduced, and the loss of the electric energy is reduced. The submodule 20 of the integrated energy storage matrix type modularized multi-level converter 10 comprises at least one energy storage battery pack 24, and the energy storage battery pack 24 is used for storing and releasing electric energy, so that fluctuation of output power of a wind turbine generator can be reduced, fluctuation of power input into a power grid can be reduced, deviation of wind power prediction can be compensated, and even primary frequency modulation and secondary frequency modulation can be achieved.
In this specification, each embodiment or implementation is described in a progressive manner, and each embodiment focuses on a difference from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the utility model.
Claims (10)
1. The integrated energy storage matrix type modularized multi-level converter is characterized in that the integrated energy storage matrix type modularized multi-level converter is connected between a generator of a fan and a step-up transformer, the frequency of alternating current output by the generator is a first frequency, the frequency of alternating current output by the step-up transformer is a second frequency, and the integrated energy storage matrix type modularized multi-level converter is used for converting the first frequency and the second frequency;
the integrated energy storage matrix type modularized multi-level converter comprises a plurality of bridge arms, each bridge arm comprises a bridge arm reactor and a plurality of submodules which are connected in series, and each submodule comprises at least one energy storage battery pack.
2. The integrated energy storage matrix modular multilevel converter of claim 1, wherein the leg reactors are inductors.
3. The integrated energy storage matrix modular multilevel converter according to claim 1 or 2, wherein a plurality of the sub-modules each further comprises: two first branches, a capacitor and a direct current port;
the two first branches and the capacitor are connected in parallel, the two ends of the two first branches and the two ends of the capacitor are respectively connected with the two direct current output ends of the direct current port, and the two ends of at least one energy storage battery pack are respectively connected with the two direct current input ends of the direct current port;
each first branch comprises two switching devices connected in series, and each switching device comprises a fully-controlled power electronic switch and a diode which are connected in parallel;
one of the energy storage battery packs includes a plurality of energy storage cells connected in series.
4. An integrated energy storage matrix modular multilevel converter according to claim 3, wherein the fully controlled power electronic switch is an insulated gate bipolar transistor or an integrated gate commutated thyristor;
when the fully-controlled power electronic switch is an insulated gate bipolar transistor, the collector of the insulated gate bipolar transistor is connected with the cathode of the corresponding diode, the emitter of the insulated gate bipolar transistor is connected with the anode of the corresponding diode, and the grid of the insulated gate bipolar transistor is connected with a peripheral circuit;
when the fully-controlled power electronic switch is an integrated gate commutated thyristor, the cathode of the integrated gate commutated thyristor is connected with the anode of the corresponding diode, the anode of the integrated gate commutated thyristor is connected with the cathode of the corresponding diode, and the gate of the integrated gate commutated thyristor is connected with a peripheral circuit.
5. An integrated energy storage matrix modular multilevel converter according to claim 3, wherein the generator is a doubly fed asynchronous generator, the direct current port is a DC-DC transformer, and the DC-DC transformer controls charging and discharging of the corresponding energy storage battery.
6. The integrated energy storage matrix modular multilevel converter of claim 5, wherein one end of the integrated energy storage matrix modular multilevel converter is connected to a rotor of the doubly fed asynchronous generator and the other end is connected to a low voltage side of the step-up transformer.
7. The integrated energy storage matrix modular multilevel converter of claim 3, wherein the generator is a permanent magnet generator, the dc port is a dc filter, and the capacitor controls charging and discharging of the corresponding energy storage battery pack.
8. The integrated energy storage matrix modular multilevel converter of claim 7, wherein one end of the integrated energy storage matrix modular multilevel converter is connected to a stator of the permanent magnet generator and the other end is connected to a low voltage side of the step-up transformer.
9. The integrated energy storage matrix modular multilevel converter according to claim 1 or 2, further comprising three first connection lines and three second connection lines, wherein one ends of the three first connection lines are connected to the generator, and one ends of the three second connection lines are connected to the low voltage side of the step-up transformer;
the number of the bridge arms is nine, the nine bridge arms are distributed in three rows and three columns, the first ends of the three bridge arms in the same column are connected to one first connecting line, and the second ends of the three bridge arms in the same row are connected to one second connecting line.
10. The integrated energy storage matrix modular multilevel converter according to claim 9, wherein three of the first connection lines are connected to three phase outputs of the generator, respectively, and three of the second connection lines are connected to three phase inputs of the step-up transformer, respectively.
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